To see the other types of publications on this topic, follow the link: Biogas potentials.
Dissertations / Theses on the topic 'Biogas potentials'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Biogas potentials.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Liu, Yang. "Greenalgae as a substrate for biogas production - cultivation and biogas potentials." Thesis, Linköping University, Linköping University, Department of Water and Environmental Studies, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57987.
Full textAbstract:
Algae is regarded as a good potential substrate for biogas production, due to high cells productivity, low cellulose and zero lignin content. Two parts were included in this study: first, cultivations of micro-algae (Chlorella sorokiniana and Tetraselmis suecica) at two different nitrate concentrations, also the effect of addition of CO2 on algae grow was investigated in this first part. Second, batch fermentations of the cultivated micro-algae as well as a powder Chlorella (obtained from Raw Food Shop) and a dry mix filamentous algae (collected in the pounds in the park at the back of the Tema-building and then dried) were performed. In this part also effects of thermo-lime pretreatment (room temperature, 80oC, 105oC and 120oC) on the algae biogas potentials was investigated.
Both strains of micro-algae cultured at low nitrate gave more CH4 yield: 319 (±26) mL and 258 (±12) mL CH4 per added gVS was obtained during the degradation of Chlorella sorokiniana grown at 0.4mM-N and 2mM-N level, respectively. For Tetraselmis suecica 337 (±37) mL and 236 (±20) mL CH4 per added gVS was obtained at 2.4mM-N and 12mM-N level, respectively. Powder Chlorella gave the highest biogas production (719 ±53 mL/added gVS) and CH4 yields (392 ±14 mL/added gVS), followed by the dry filamentous algae (661 ±20 mL biogas and 295 ±9 mL CH4 per added gVS) and Tetraselmis suecica (12 mM-N; 584 ±7 mL biogas and 295 ±9 mL CH4 per added gVS).
A negative effect of lime treatment at room temperature on CH4 yield of algal biomass was obtained. Lime treatment at 120oC showed the fastest degradation rate for Tetraselmis suecica and powder Chlorella during the initial 5 days of incubation.
Chlorella sorokiniana and Tetraselmis suecica cultures flushed with biogas containing 70% and also CO2 enriched air (5% CO2) did not increase cells growth (measured as OD600) if compared to references grown under air. On the contrary, a clearly inhibition effect on the algal cells growth was observed in some cultures.
2
Miranda, Nicole. "Meta-analysis of GHG mitigation potentials of the application of anaerobic digestion in dairy farms." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:d613759f-8f42-494e-8e95-e977a5fc41b4.
Full textAbstract:
Dairy farms can apply anaerobic digestion (AD) as a manure management system, while producing renewable energy. Ultimately, this can reduce greenhouse gas (GHG) emissions. There is much research work that has quantified the changes in emissions due to AD. However, important methodologies such as the Intergovernmental Panel on Climate Change (IPCC) Guidelines, rely only on a small sample of the accumulated scientific findings in the field. This thesis improves the robustness of these methodologies by applying data-driven techniques to estimate values of the energy output of AD systems and their consequent effect in GHG emissions. For this purpose, meta-analyses techniques are applied to mathematically combine metrics from 155 non-standardised research publications (i.e. with different boundaries, scopes and functional units). As a first step, a novel database is created by systematically searching for relevant articles and assessing them against defined criteria. The database is divided in two parts. Given that the offset of GHGs is highly dependent on the energy output of AD system, empirical methane yields (i.e. key metric of AD performance) are collected in Part I of the database. GHG released from different farm activities are input to Part II of the database. To quantify the change in emissions from these activities, standard baseline and AD scenarios are defined. The second step of the meta-analysis consists of applying uni- and multi-variate tests to the database. For Part I, methane yields are analysed in terms of type of digesters. From the batch digesters, new maximum methane yields are proposed based on the combined results of 42 peer reviewed articles. These results offer better estimates than default values of methane yields from the 2007 Guidelines of the IPCC, which only consider two studies. For continuously stirred tank digesters and semi-continuous digesters lower methane yields are revealed. Multi-variate analysis of methane yields together with operating conditions and manure composition, enable the identification of clusters. These groups of variables can be useful to build potential AD scenarios in dairy farms. For Part II of the database, relative changes in emissions between the activities in the standardised baseline and AD scenarios, are examined. It is found, through meta-analysis, that replacing raw manure by anaerobically-treated manure (i.e. digestate) in storage tanks and for field- application, mitigates baseline emissions by 38.7% and 6.9%, respectively. These relative changes can be used to estimate emissions from digestate, being more specific and evidence-based than the current methodology from the IPCC. In addition, relative changes found for offset of fossil fuels by biogas generated in the AD scenarios indicate a reduction of baseline emissions by 9.0%. Only methane leaks from digesters significantly increase the baseline emissions (by 7.4%). Finally, results found by meta-analyses of methane yields and changes in emissions are applied to four dairy farm case studies. The work presented in the case studies demonstrates the benefits of enhancing the robustness of methods to estimate the effect of AD on GHG emissions from dairy farms.
3
Kincl, Karel. "Potential of Biomass and Biogas Energy Projects in the Czech Republic." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-73156.
Full textAbstract:
The aim of my Master Thesis is to provide the reader a holistic picture about the current situation on the renewable energy market, specifically in the area of biomass energy. Firstly, the complex research, which had been conducted by the European Union, Czech government and individual research groups, was examined to make a comprehensive overview about the Czech energy mix of renewable sources. Secondly, the biomass energy fundamentals were elaborated in more details to provide the reader solid insights into the biomass origins, methods of energy conversion as well as its current market circumstances. Next, the financing structure of biomass energy projects together with SWOT analysis on biomass was conducted based on the personal work experience from the Department of Renewable Energy Financing at xxxxxxxxxx bank and the available analytical materials. Consequently, the recommendations for potential biomass investors were concisely described together with the market prediction and possible outlook that was suggested based on the previous analysis.
4
Barth, Matthias. "Erschließung von Biogaspotenzialen aus Überschussschlamm mit Hilfe der Kombination aus Desintegration und anaerober Schlammstabilisierung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-89275.
Full textAbstract:
Auf Grund der Zielstellungen des Klimaschutzes und den Szenarien der Ressourcenverfügbarkeit sowie der Energiekostenentwicklung wird das Energiemanagement bei der Betriebsführung von Abwasser- und Schlammbehandlungsanlagen an Bedeutung gewinnen, wobei die Maßnahmen des Energiemanagements mit den grundlegenden Zielen der Abwasser- und Schlammbehandlung zu vereinen sind. Zentrale Elemente des Energie-managements stellen die Nutzung eines breiten Energiespektrums und der Einsatz energieeffizienter Betriebsführungen, Techniken und Technologien dar. Eine Möglichkeit betriebstechnischer Optimierungen besteht in der Anwendung der Verfahrenskombination aus Desintegration und anaerober Schlammstabilisierung.
Seit 10 – 15 Jahren wurde intensiv auf dem Gebiet der Klärschlammdesintegration geforscht, ohne dass allgemeingültige Aussagen über die Möglichkeiten der Desintegration ermittelt wurden. Anlässlich der dargestellten Sachlage und eigener Forschungsarbeiten auf dem Gebiet der Klärschlammdesintegration entstand die Idee zur vorliegenden Arbeit.
Die Arbeit gibt in einer Literaturrecherche einen umfangreichen Überblick vorhandener Untersuchungen zur Verfahrenskombination Klärschlammdesintegration und anaerobe mesophile Schlammstabilisierung. Zu den untersuchten Desintegrationsapparaten und techniken gehören Rührwerkskugelmühle, Ultraschallhomogenisator, Hochdruck-homogenisator, Lysatzentrifuge, thermische Vorbehandlung, Hochleistungspulstechnik, Ozonbehandlung und die Kombination von thermischer Vorbehandlung mit Säuren- bzw. Laugenaufschluss.
Zur Verbesserung der für die Auswertungen benötigten Datenbasis wurden labortechnische Untersuchungen zur anaerob mesophilen bzw. zur anaerob thermophilen Überschussschlammstabilisierung sowie zur Verfahrenskombination von Überschussschlammdesintegration mit anaerob mesophiler bzw. anaerob thermophiler Schlammstabilisierung durchgeführt Zur Desintegration wurden eine Rührwerkskugelmühle PE 075 (Fa. Netzsch-Feinmahltechnik), eine Fliehkraftkugelmühle S 100 (Retsch GmbH), ein Ultraschallhomogenisator UP 400S (Fa. Dr. Hielscher GmbH) eingesetzt sowie ein thermischer Aufschluss bei 75 °C und eine Kombination von thermischem Aufschluss bei 75 °C mit anschließender Unterdruckentspannung durchgeführt.
Die vorliegende Arbeit beinhaltet eine umfangreiche Bewertung der Verfahrenskombination Überschussschlammdesintegration mit anschließender anaerob mesophiler Schlammstabilisierung. Speziell wurden in diesem Zusammenhang gezielte Untersuchungen zu variierenden Klärschlammqualitäten, Milieubedingungen der anaeroben Stabilisierung (Verweilzeit, Temperatur) und Desintegrationsverfahren (mechanisch, niederthermisch) durchgeführt. Die Auswertungen zeigen, dass die Wirkung dieser Verfahrenskombination maßgeblich durch die anaerobe Abbaubarkeit der Referenzüberschussschlämme bestimmt wird, wobei sich der relative Einfluss der Desintegration mit steigendem Stabilisierungsgrad der Überschussschlämme erhöht. Als Grenze des organischen Abbauverhaltens von desintegrierten Überschussschlämmen kann von einem GV Abbau 59 % bzw. von einem zufuhrspezifischen Biogasanfall von 467 Nl/kg GVZu ausgegangen werden. Die aus der Desintegration resultierende Steigerung des anaeroben Abbauverhaltens von Überschussschlämmen bedingt einen Anstieg der CSBmf- bzw. NH4-N-Prozesswasserbelastung. Für die PO4-P- bzw.- Pges,mf-Anteile des Prozesswassers war kein Zusammenhang nachweisbar.
Für die Verfahrenskombination Überschussschlammdesintegration mit anschließender anaerob mesophiler Schlammstabilisierung werden neben dem Einsatz zur Verbesserung des anaeroben Abbauverhaltens von Überschussschlämmen Anwendungsmöglichkeiten zur Sanierung überlasteter Faulbehälter bzw. zur Minimierung notwendiger anaerober Reaktionsvolumina aufgezeigt. Entsprechend der Ergebnisse dieser Arbeit ist durch eine vorgeschaltete Überschussschlammdesintegration eine Verkürzung der anaeroben Stabilisierungszeit von 16 – 24 d auf 7 – 12 d möglich, ohne dass eine Verminderung des organischen Abbaus von Überschussschlämmen toleriert werden muss.
Gesonderte Auswertungen befassen sich mit der Wirkung der Desintegration auf die anaerobe Abbaubarkeit der im Überschussschlamm enthaltenen Stoffgruppen Fette, Kohlenhydrate und Eiweiße. Es ist festzustellen, dass das anaerob mesophile Abbauverhalten einzelner im Überschussschlamm gebundener Stoffgruppen infolge einer Vorbehandlung durch Desintegrationsverfahren nicht/oder nur unwesentlich verändert wird.
Im weiteren Verlauf der Arbeit wurden Nomogramme zur Prognose des Desintegrations-einflusses auf das anaerob mesophile Abbauverhalten von Überschussschlämmen erarbeitet, die es dem planenden Ingenieur bzw. dem Betriebsingenieur gestatten, die Auswirkungen eines Einsatzes der Kombination von Überschussschlammdesintegration und anaerob mesophiler Stabilisierung zu bewerten. Die Darstellungen ermöglichen eine Spezifizierung nach dem Grad der mechanischen Abwasserbehandlung und des in der biologischen Abwasserbehandlung praktizierten Gesamtschlammalters. Die Prognosemöglichkeiten umfassen den für desintegrierte Überschussschlämme bei der anaerob mesophilen Schlamm-stabilisierung auftretenden GV Abbau, den zufuhrspezifischen Biogasanfall sowie die resultierende CSBmf- und NH4-N-Prozesswasserbelastung. In Abhängigkeit der Verfahrens- und Betriebsführung der Abwasserbehandlung führt die Desintegration im Mittel zu einer maximalen absoluten Veränderung des GV-Abbaus bzw. des zufuhrspezifischen Biogas¬anfalls von Überschussschlämmen von 13 % bzw. 90 l/kg GVZu. Die Spannweiten der CSBmf- bzw. NH4-N-Prozesswasserbelastung betragen 0,5 – 6,5 % bzw. 3,0 – 18,0 % der Frachten des Kläranlagenzulaufes.
Die vorliegende Arbeit enthält erstmals Ergebnisse zur Verfahrenskombination Überschussschlammdesintegration mit anschließender anaerob thermophiler Schlammstabilisierung. Gemäß den Versuchsauswertungen werden das anaerobe Abbauverhalten von Überschussschlämmen unter thermophilen Milieubedingungen und die daraus resultierenden Prozess-wasserbelastungen durch eine vorgeschaltete Überschussschlammdesintegration nur unwesentlich beeinflusst.
Abschließend ordnet die Arbeit das Leistungsvermögen der Verfahrenskombination Über-schussschlammdesintegration + anaerob mesophile Schlammstabilisierung gegenüber anderen Optimierungsmöglichkeiten der anaeroben Schlammstabilisierung ein. Die Untersuchungen zeigen, dass durch einen Wechsel des Temperaturniveaus der anaeroben Schlammstabilisierung vom mesophilen in den thermophilen Bereich der unter mesophilen Bedingungen erreichbare GV Abbau bzw. zufuhrspezifische Biogasanfall unbehandelter Überschussschlämme ähnlich beeinflusst werden kann, wie es durch die Kombination von Überschussschlammdesintegration und anschließender anaerober mesophiler Schlammstabilisierung möglich ist. Gleichzeitig ist bei der anaerob thermophilen Stabilisierung unbehandelter Überschussschlämme gegenüber der anaerob mesophilen Stabilisierung desintegrierter Überschussschlämme eine höhere Prozesswasserbelastung zu erwarten.
5
Granato, Eder Fonzar [UNESP]. "Análise de viabilidade técnica e econômica da biodigestão anaeróbia da vinhaça." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/141880.
Full textAbstract:
Submitted by EDER FONZAR GRANATO null (eder1962granato@gmail.com) on 2016-07-18T15:30:51Z
No. of bitstreams: 1
TESE EDER FONZAR GRANATO 1962 com ficha.pdf: 2663771 bytes, checksum: 91f29e8fd5aa752f16fc4d9ab7721195 (MD5)Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-07-19T20:46:25Z (GMT) No. of bitstreams: 1 granato_ef_dr_bot.pdf: 2663771 bytes, checksum: 91f29e8fd5aa752f16fc4d9ab7721195 (MD5)
Made available in DSpace on 2016-07-19T20:46:25Z (GMT). No. of bitstreams: 1 granato_ef_dr_bot.pdf: 2663771 bytes, checksum: 91f29e8fd5aa752f16fc4d9ab7721195 (MD5) Previous issue date: 2016-05-25
O Brasil produz anualmente 30 bilhões de litros de etanol de cana de açúcar com previsão do Ministério de Minas e Energia de atingir 36 bilhões de litros em 2024. A vinhaça é o resíduo líquido, rico em potássio e matéria orgânica que resulta da destilação do etanol, na proporção de 10 a 15 litros de vinhaça para cada litro de etanol. Disposto indevidamente, pode trazer sérios riscos para o ambiente devido ao alto potencial poluidor. Os estados de São Paulo, Paraná e Mato Grosso do Sul, possuem normas específicas sobre disposição desse resíduo, mas não atingem por completo o objetivo de controlar e mitigar os problemas, pois a disposição final da vinhaça se resume unicamente na fertirrigação sem qualquer outro tratamento. No presente trabalho, realizado no Laboratório de Biomassa do Departamento de Engenharia Rural da Faculdade de Ciências Agrárias e Veterinárias da UNESP de Jaboticabal, analisou-se a biodigestão anaeróbia da vinhaça, caracterizando-se a produção de biogás e a redução do potencial poluidor. Para tanto, foram efetuados estudos de viabilidade técnica da biodigestão anaeróbia da vinhaça analisando os parâmetros: neutralização do pH da vinhaça, utilização do reciclo e estabilização da temperatura da vinhaça. Para os três parâmetros citados foram registrados e analisados dados referentes a: produção de biogás (m3), composição do biogás (% de CH4 e CO2) e redução do potencial poluidor da vinhaça após biodigestão anaeróbia (DQO). No que diz respeito a produção do biogás, os resultados considerados relevantes foram na correção do pH (aumento de 97,5%) e no aquecimento do afluente (aumento de 79%). Em relação a composição do biogás, obteve-se, aumento de 9% de metano redução de 3,6% de dióxido de carbono quando se aquece o afluente. Quando se utiliza reciclo a redução de DQO aumentou em 50% e o aquecimento do afluente permitiu aumentou a redução em 62%, demonstrando a viabilidade técnica do presente estudo. Para se determinar a viabilidade econômica foram efetuados estudos referentes a: Demonstração do Fluxo de Caixa, Valor Presente Liquido, Taxa Interna de Retorno e Payback Descontado. Em relação ao Valor Presente Liquido, o resultado obtido foi de R$ 2.179.331,76, maior que zero. A Taxa Interna de Retorno foi de 8%, maior que 7,5% (Taxa Atrativa Mínima). O retorno do investimento pelo cálculo do Payback Descontado será em 5,54 anos, provando assim que o projeto é viável economicamente.
The Brazil annually produces 30 billion liters of ethanol from sugar cane with the Ministry of Mines and Energy forecast to reach 36 billion liters in 2024. The stillage is the liquid waste, rich in potassium and organic matter resulting from the distillation of ethanol in the proportion of 10 to 15 liters of vinasse per liter of ethanol. Willing improperly, can pose serious risks to the environment due to the high pollution potential. The states of São Paulo, Paraná and Mato Grosso do Sul, have specific rules on disposal of this waste, but do not reach completely in order to control and mitigate the problems because the final disposal of vinasse comes down solely in fertigation without any other treatment . In this study, conducted at the Laboratory of Biomass Department of Rural Engineering of the Faculty of Agricultural and Veterinary Sciences of Jaboticabal UNESP, analyzed the anaerobic digestion of vinasse, characterizing the production of biogas and reduce the pollution potential. Therefore, technical feasibility studies of anaerobic digestion of vinasse were made by analyzing the parameters: pH neutralization of vinasse, use of recycling and stabilization of vinasse temperature. For the three mentioned parameters were recorded and analyzed data for: biogas production (m3), biogas composition (% CH4 and CO2) and reduced pollution potential of vinasse after anaerobic digestion (COD). As regards the production of biogas, the results were considered significant at pH correction (increase of 97.5%) and heating the influent (79% increase). For biogas composition was obtained, an increase of 9% methane 3.6% reduction of carbon dioxide when heated affluent. When COD reduction using recycled increased by 50% and heating affluent allowed increased the reduction by 62%, demonstrating the technical feasibility of this study. To determine the economic feasibility studies were made regarding: Cash Flow Statement, Net Present Value, Internal Rate of Return and Discounted Payback. Regarding the Net Present Value, the result was of R$ 2,179,331.76, greater than zero. The internal rate of return was 8%, higher than 7.5% (rate Attractive Minimum). The return on investment by calculating the Discounted Payback will be 5.54 years, thus proving that the project is economically viable.
6
Almansour, Essam. "Bilans énergétiques et environnementaux de filières biogaz : approche par filière-type." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14469/document.
Full textAbstract:
La méthanisation émerge comme une technique efficace pour la production énergétique ainsi que le traitement des résidus organiques. Une analyse de la méthanisation dans les différentes filières sélectionnées est menée par une démarche reposant sur la définition de filières-type, renseignées à partir d'enquêtes techniques auprès des installations existantes et des professionnels. Ces filières-type nous permettent d’étudier globalement les bilans énergétiques et environnementaux de la digestion anaérobie pour la comparer avec d’autres procédés en utilisant l’approche par analyse du cycle de vie. Énergétiquement, un potentiel important de plus de 11 Mtep/an est estimé à partir des ressources disponibles dans les filières retenues. Les ressources agricoles contribuent à une part importante de ce potentiel. Les déchets résiduaires des industries agroalimentaires complètent ce potentiel sachant que la quantité des déchets méthanisables est importante sur le territoire français. Environnementalement, le biogaz valorisé procure un avantage à la méthanisation devant la filière de comparaison. Les résultats des études comparatives d’ACV sont sensibles à la méthode d’analyse d’impact retenue par rapport à leur sensibilité à certains aspects. Les résultats d’ACV sont aussi sensibles à la définition des filières et alors définir d’autres filières lorsque des interrogations subsistent est une perspective importante à ne pas négligerAnaerobic digestion is emerging as an efficient technology for energy production as well as for of organic residues treatment. An analysis of the anaerobic digestion in different chosen procedures is led by an approach based on the standard procedures definition, filled from technical investigations with existing installations and professionals. These standard procedures allow us to study the overall energy and environmental balance sheets of anaerobic digestion in order to compare it with other processes by using the approach of life cycle assessment. Energetically, an important potential for more than 11 Mtoe/year is estimated from available resources in chosen procedures. Agricultural resources contribute to a significant portion of this potential. The residual waste from food industries completes this potential knowing that the amount of waste processed with anaerobic digestion is important on the french territory. Environmentally, the biogas recovered is advantageous to anaerobic digestion against comparison procedures. The results of comparative studies of LCA are sensitives to the impact assessment method adopted in relation to their sensitivity to certain aspects. The LCA results are also sensitives to the definition of procedures and define other procedures, when we have doubts, remains an important perspective not to be neglected
7
Khayi, Noureddine. "Uthållig avloppsrening : Biogas potential på avloppsvatten." Thesis, KTH, Industriell ekologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-149484.
Full textAbstract:
Projektet genomfördes vid IVL Svenska Miljöinstitutet i Hammarby Sjöstadsverk i samarbete med Kungliga Tekniska Högskolan (KTH). Syftet med detta projekt är att jämföra biogas potential mellan tre olika förbehandlingsmetoder av avloppsslam före rötningen, dessa metoder är djup och lätt frysning samt uppvärmning av slammet. Rötningsprocesser kan göras vid olika temperatur, olika inmatningshastighet och olika antal steg. Oavsett exakt utformning innebär rötningen fyra steg: hydrolys, fermentering, anaerob oxidation och metanbildning. Vid rötningen produceras metangas vilken används till uppgradering för att producera fordonsbränsle, värmeproduktion, elproduktion och fackling. Det har visat sig att förbehandlingsmetoderna har en stor potential för att utöka gas produktionen genom förbehandling av avloppsvattensslam före en anaerob rötning som utfördes i laboratorieskala med hjälp av ”Automatisk Metan Potential Test System(AMPTS II). Experimentet visade på lovande resultat, det har skett en ökning av metanutbytet på två av dem testade metoderna i jämförelse med det obehandlade slammet och ett referensprov med bara inocolum. Försöket avslutades efter 35 dagarsrötning, den optimala metanpotentialen som erhålls var 0,25 Nm3 CH4/kg VS framställd av djupfrystslam och 0,21 Nm3 CH4/kg VS producerad av uppvärmt slam, detta betyder en förbättring på biogas potential med 34 respektive 16 procent men lättfryst slam procentuella minskningen av metan potential ligger på 21 procent mot det obehandlade slammet. 1 Nm3 biogas motsvarar cirka 1 liter bensin som ger lika lång körsträcka, men är något billigare, bilarna får dessutom en 5–10 dB lägre bullernivå, detta uppfattas som hälften så bullrigt som ett dieseldrivet (Stockholm Vatten, 2004) På grund av att det krävs stora anläggningar och mycket slam för att få lönsamhet i verksamheten är rötningen av avloppsslam idag koncentrerad till storstadsregionerna. Genom att röta avloppsslammet minskar mängderna som behöver gå till deponi och klimatvinster kan göras då biogas ses som klimatneutral till skillnad från fossila bränslen. Att investera i biogasutvinning innebär även en ekonomisk risk då distributionsnätet inte är helt utvecklat och konsumenters intresse för bränsleformen ur ett mer långsiktigt perspektiv är svårbedömt. Det finns dock flera goda exempel på lönsamma anläggningar, ett sådant är i Stockholm där reningsverken idag levererar biogas till SL:s bussar vilket ger tystare gator och mindre partiklar i stadsmiljön (SL, 2010). Trots att det finns en del frågetecken kring exakt hur stor potential för produktionen är och att en ökning troligen samverkar med en ökad vilja att satsa på bränslet både från myndigheter, företag och enskilda konsumenter finns det en framtid för rötningen. Rötningen av avloppsslam för att producera biogas bör inte ses som en enskild energikälla utan snarare som ett komplement och ett sätt att utnyttja de resurser vi har för att skapa ett mer hållbart samhälle. Därför är satsningar och investeringar för att utveckla produktion och distribution av biogas från rötning vid avloppsreningsverk väl motiverade och bör uppmuntras.The project was carried out at the Swedish Environmental Research Institute in Hammarby Sjöstadsverk in collaboration with the Royal Institute of Technology (KTH). The purpose of this project is to compare the biogas production based on different methods of pretreatment of sewage sludge before digestion. The digestion process can be done at different temperature, different feed rate and different number of steps. Whatever the precise formulation involves digestion of four steps: hydrolysis, fermentation, anaerobic oxidation and methane formation. Upon digestion produced methane gas which is used to upgrade to produce vehicle fuel, heat, power generation and flaring. There is a potential to expand gas production by those methods in this project, tested for pretreatment of wastewater sludge prior to anaerobic digestion in a laboratory scale using Automatic Methane Potential Test system ( AMPTS II).The experiment showed promising results; there has been an increase in methane yield in comparison with untreated sludge and reference samples with only inoculums. The experiment ended after 35 days of digestion, the optimum methane potential obtained was 0.25 Nm 3 CH4/kg VS made of deep frozen sludge and 0.21 Nm 3 CH4/kg VS produced by the heated sludge this means that deep freezing enhances the biogas potential with 34 % and the heating of the sludge by 16 % but easily frozen sludge had less methane potential than the untreated sludge by 21 %. Because of the need for a large facilities and much sludge to get a profitable operation, the anaerobic digestion of sewage sludge is now concentrated in the metropolitan areas. By digesting sewage sludge reduces the amounts that need to go to landfill and climate gains can be achieved when biogas is seen as carbon neutral, unlike fossil fuels. Investing in biogas production also involves a financial risk when the distribution network is not fully developed, and consumer interest in fuel form from a longer term perspective is difficult to assess. However, there are several good examples of profitable plants; one is in Stockholm, where treatment plants currently supply biogas to SL's buses for quieter streets and less particles in the urban environment. Although there are some questions about how exactly great potential for production and that an increase is likely interacts with an increased willingness to invest in the fuel from authorities, companies and individual consumers, there is a future for digestion. Anaerobic digestion of sewage sludge to produce biogas should not be viewed as a single energy source, but rather as a supplement and a way to exploit the resources we have for creating a more sustainable society. Therefore, initiatives and investments to develop the production and distribution of biogas from anaerobic digestion at wastewater treatment plants well justified and should be encouraged.
8
Olsson, Alexander. "A Comparative Study of Swedish and Chinese Biogas Production with a Brief Economical Feasibility Analysis." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-150785.
Full textAbstract:
This Master of Science and Engineering thesis in Chemical Engineering treats biogas production in China. The thesis is divided into two parts. The first part contains an energy potential and situation analysis of biogas in China and a comparison with the situation in Sweden. The biogas potential in China is 950-2180 TWh depending on source. Specially, the potential from fish waste is 11 TWh. Part 1 also includes batch experiments where co-digestion of corn straw and swine manure is performed using substrate from Dajugezhuang in Tianjin. The experiments were executed at Tianjin Academy of Environmental Science. The experiments do not show a significant reduction in COD when co-digesting manure with straw and are connected with uncertainty. The experiments should be executed again with the recommendations given in this report. It is discovered that the inoculum affects the C:Nratio a lot. When co-digesting experiments are being performed, an inoculum that have a C:N-ratio close to the desired must be used. This is due to that the organic loading rate must be kept low. Part 2 of this thesis is an economical feasibility analysis and market investigation of biogas in China. A model is created using excel, where economic data from biogas plants in China are used to estimate the profit of producing biogas in China. The model indicates that the most feasible choice is to upgrade the biogas and inject it to the gas grid. This is due to the lower investment cost for an upgrading unit compared to an electricity-generating unit. The model uses electricity and gas prices from different provinces in China. Guangdong is the province with the highest electricity price and Ningxia the province with the lowest electricity price. The gas price in Guangdong is also high, but highest in Guangxi and Yunnan. The lowest gas price is found in Ningxia. Part 2 also discuss problems with the current situation for biogas producers in China. Investment subsidies from the government instead of product subsidies has led to a situation where China has over 30 million biogas reactors, but very low yield. The current situation means low incentives for selling the products from anaerobic digestion, biofertilizers, bio-methane, electricity and heat. The grid connection limit on electricity generators of >500 kW limits the number of grid-connected plants to less than 10. viDetta examensarbete i kemiteknik behandlar biogasproduktion i Kina. Examensarbetet är uppdelat i två delar. Den första delen innehåller en energipotential och nulägesanalys av biogas i Kina och en jämförelse med situationen i Sverige (kapitel 1). Biogas potentialen i Kina är 950-2180 TWh beroende på olika källor. Speciellt är potentialen från fiskarens 11 TWh. Del 1 omfattar även satsvisa utrötningsförsök där samrötning av majshalm och svingödsel sker med hjälp av substrat från Dajugezhuang i Tianjin. Experimenten utfördes vid Tianjin Academy of Environmental Science. Experimenten visar inte en signifikant minskning av COD vid samrötning av grisgödsel med halm och försöken är behäftade med osäkerhet. De bör därför genomföras igen efter de rekommendationer som ges i denna rapport. Det upptäcks att den ymp som används påverkar C:N-kvoten mycket. När samrötningsexperiment genomförs, ska en ymp som har en C:N-kvot nära den önskade för försöket användas. Detta beror på att den organiska belastningen måste hållas låg. Del 2 i detta examensarbete är en feasibility-analys och marknadsundersökning av biogas i Kina. En modell skapades i Excel, där ekonomiska data från biogasanläggningar i Kina används för att uppskatta resultatet att producera biogas i Kina. Modellen visar att det mest ekonomiska sättet att använda biogasen är att uppgradera den och injicera det till gasnätet. Detta beror på den lägre investeringskostnaden för en uppgraderingsanläggning jämfört med ett elkraftverk. Modellen använder el- och gaspriser från olika provinser i Kina. Guangdong är provinsen med det högsta elpriset och Ningxia provinsen med det lägsta elpriset. Gaspriset i Guangdong är också hög, men högst i Guangxi och Yunnan. Det lägsta priset på gas finns i Ningxia. Del 2 diskuterar också problem med den nuvarande situationen för biogasproducenter i Kina. Investeringsstöd från staten i stället för subventioner av produkterna har lett till en situation där Kina har över 30 miljoner biogasreaktorer, men mycket lågt utbyte i reaktorerna. Den nuvarande situationen innebär få incitament för försäljning av produkterna från rötningsprocessen, bio-gödsel, bio-metan, el och värme. Den nätanslutningsgräns som finns för elproducenterna på >500 kW, begränsar antalet nätanslutna anläggningar i Kina till mindre än 10 stycken. vii
9
Shi, Chen. "Potential Biogas Production from Fish Waste and Sludge." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171807.
Full textAbstract:
In order to decrease the pollution of the marine environment from dumping fish waste and by-catch, alternative use for co-digestion with sludge in anaerobic condition was studied. The purpose of this project is to optimize the methane potential from adjustment of the proportion among mixed substrates. Ten groups of different proportions among fish waste, by-catch and sludge were conducted with AMPTS II instrument under mesophilic condition (37 ± 0.5 ºC), by means of the principle of BMP test. The ratio of inoculums and mixed substrate was set as 3:2. The optimal MP obtained after an experiment with 13 days digestion was 0.533 Nm3 CH4/kg VS from the composition of sludge, by-catch and fish waste as 33 %, 45 % and 22 %. It was improved by 6 % and 25.6 %, to compare with the previous studies by Almkvist (2012) and Tomczak-Wandzel (personal communication, February 2012) respectively.
10
Lopes, Alice do Carmo Precci. "Biogas production potential from kraft pulp mill sludge." Universidade Federal de Viçosa, 2017. http://www.locus.ufv.br/handle/123456789/10437.
Full textAbstract:
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-05-30T13:10:23Z
No. of bitstreams: 1
texto completo.pdf: 2018178 bytes, checksum: f542263170df07213000e3e4bebf72ed (MD5)Made available in DSpace on 2017-05-30T13:10:23Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2018178 bytes, checksum: f542263170df07213000e3e4bebf72ed (MD5) Previous issue date: 2017-03-28
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O processo de fabricação da polpa celulósica kraft demanda elevada quantidade de água e energia. Embora a indústria gere parte de sua própria energia pela queima do licor negro na caldeira de recuperação e biomassa residual na caldeira de biomassa, a indústria ainda é dependente de energia elétrica e combustíveis fósseis adicionais. Devido ao aumento da tarifa de energia, a indústria de celulose tem sido motivada a aumentar sua eficiência energética, tornando-se autossuficiente. A produção de biogás a partir do lodo gerado na estação de tratamento de efluentes da indústria constitui uma potencial alternativa de gerenciamento dos resíduos e produção de energia. O objetivo principal desta dissertação foi avaliar o potencial da produção de biogás a partir dos lodos primário e secundário provenientes da indústria de celulose kraft branqueada. A dissertação foi estruturada em 5 Capítulos desenvolvidos em forma de artigos científicos. O Capítulo 1 apresentou uma revisão de literatura sobre os processos de produção de celulose kraft e de biogás, bem como um panorama sobre legislações brasileiras relacionadas à implantação de biodigestores. Foi concluído que há pouco estudo relativo à digestão anaeróbia de lodo de celulose kraft. Adicionalmente, apesar de o Brasil apresentar um grande potencial de produção de biogás, o país ainda carece de incentivos governamentais no setor. O Capítulo 2 objetivou (i) identificar a melhor relação substrato/inóculo (2/1, 1/1 e 0.4 g VS substrato /g VS inóculo ); (ii) identificar o melhor tipo de inóculo (lodo de UASB ou lodo de UASB + estrume); e (iii) estimar o potencial de substituição da energia elétrica demandada pelo sistema de aeração da estação de tratamento de efluentes da indústria de celulose kraft branqueada a partir do biogás produzido. Para tanto, foram utilizados como substratos o lodo primário (PS), lodo secundário (SS) e a mistura de ambos (MIX). Os resultados mostraram que o lodo secundário possuiu maior potencial de produção de biogás para uma relação 1/1 g VS substrato /g VS inóculo , utilizando lodo de UASB como inóculo. O estrume aumentou a produção de metano do lodo primário para relação S/I 1/1, porém pré-tratamentos devem ser testados de modo a aumentar a biodegradabilidade do substrato. Por fim, o biogás produzido apresentou potencial de substituir 23% daxi demanda de energia elétrica da estação de tratamento de efluentes. O Capítulo 3 objetivou (i) estimar o potencial de produção de biogás em condições termofílicas a partir do PS, SS e MIX; (ii) calibrar o modelo de digestão anaeróbia desenvolvido por Rajendran et al. (2014); e (iii) determinar a melhor composição do lodo e a influência de adição de nitrogênio no sistema de digestão anaeróbia a partir de simulações numéricas. Foi identificado que (i) a máxima produção de metano foi atingida pelo lodo secundário em 30 dias (46.9 NmL CH4/g VS); (ii) o modelo de digestão anaeróbia foi aplicável para lodo de celulose kraft após ajustes; (iii) a melhor composição de lodo foi de 21.62% de carboidratos, 61,67% de lipídeos e 16.72% de proteínas. A adição de nitrogênio aumentou a produção de metano para o PS e o MIX, mas reduziu para o SS. Os Capítulos 4 e 5 foram desenvolvidos por estudantes intercambistas como parte do programa Living Lab Biobased Brazil. Os objetivos do Capítulo 4 foram ajustar o modelo de Rajendran et al. (2014) para a condição mesofílica e simular o uso do biogás em forma de eletricidade e calor. A partir da simulação foi possível produzir 88 GJ/d de calor e 148 kW de potência elétrica. Além disso, a partir do ajuste do modelo de Rajendran et al. (2014) para a condição mesofílica, foram propostas melhorias para o modelo. Por fim, o Capítulo 5 objetivou apresentar potenciais alternativas para o gerenciamento do lodo de celulose kraft pós-digestão anaeróbia, utilizando a ferramenta de Análise de Multi-Critério simplificada. A partir das alternativas avaliadas (aterro sanitário, aplicação no solo, compostagem, incineração, pirólise/gaseificação e produção de algas), a compostagem se apresentou como a melhor opção.
The kraft pulping process is energy intensive. Although the mill generates part of its own energy by burning the black liquor in the recovery boiler and wooden biomass in the biomass boiler, it still relies on additional electricity and fossil fuel sources. Due to an energy price increase, the pulp industry has been driven to optimize its energy efficiency and self-sufficiency. One attractive industrial opportunity is to produce biogas from sludge using the anaerobic digestion technology. Thus, the main objective of this dissertation was to evaluate the potential of biogas production from bleached kraft pulp mill primary and secondary sludges. The dissertation was structured in 5 Chapters written as scientific papers. Chapter 1 presented a literature review about kraft pulp mills, biogas production, and legislations related to the implantation of biodigesters. It was concluded that there are still very few studies related to the anaerobic digestion of kraft pulp mill sludges. Additionally, although Brazil has great potential for biogas production, the country still faces barriers related to political incentives. Chapter 2 aimed at (i) identifying the best substrate to inoculum ratio (2/1, 1/1, and 0.4 g VS substrate /g VS inoculum ); (ii) identifying the best inoculum type (UASB sludge and UASB sludge + cow dung); and (iii) estimating the potential of substituting the electricity demand of the mill’s effluent treatment plant (ETP) aeration system. The substrates used consisted of primary (PS) and secondary (SS) sludges, and the mixture (MIX) between PS and SS. The results showed that the SS presented the highest methane production, with an optimal ratio of 1 g VS substrate /g VS inoculum using UASB sludge as inoculum. Cow dung increased the methane production of the PS for S/I = 1/1, but pre-treatment of PS should be tested to increase the substrate biodegradability. Finally, the methane yield led to a potential substitution of 23% of the ETP electricity demand. Chapter 3 aimed to (i) estimate potential biogas production under thermophilic conditions for the same substrates; (ii) calibrate the anaerobic digestion model developed by Rajendran et al. (2014); and (iii) simulate the best sludge composition and the influence of nitrogen addition on anaerobic digestion system. It was found that the (i) the maximum methane yield was achieved with theix secondary sludge at 30 days (46.9 NmL CH4/g VS); (ii) the applied anaerobic digestion model was applicable for the kraft pulp mill sludge after minor adjustments; (iii) optimal sludge composition was found to be 21.62% carbohydrates, 61.67% lipids and 16.72% proteins. The addition of nitrogen increased the methane yield for PS and MIX, but decreased it for SS. Chapters 4 and 5 were the result of work developed by bachelor exchange students as part of the Living Lab Biobased Brazil Program. Chapter 4 aimed to adjust the Rajendran et al. (2014) model for mesophilic conditions and simulate biogas use in the form of electricity and heat. From the simulation, a potential heat production of 88 GJ/d and electric power of 148 kW was found. From Chapter 4, possibilities for improving the Rajendran et al. (2014) model were proposed. Finally, Chapter 5 aimed at giving an insight into the possible alternatives for managing the anaerobically digested kraft pulp mill sludge using a simplified Multi- Criteria Decision Analysis tool. From the analyzed alternatives (landfill, land application, composting, incineration, pyrolysis/gasification and algae production), composting appeared to be the most suitable alternative.
11
Björklund, Simon, and Niklas Öhman. "Biogas opportunities in Curitiba : Analysis of business potential for biogas production from municipal solid waste." Thesis, KTH, Energiteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211698.
Full textAbstract:
The Brazilian city ofCuritiba produces 2 500 tons of MSW (municipal solid waste) per day that is landfilled.In an effort to find a more sustainable solution for waste management, the objective of this study was to investigate the potential for producing biogas from anaerobic digestion by analyzing the feasibility of small-scale decentralized biogas production as well as centralized production at commercialscale. A field study was carried out to map specific local circumstances and togather data by interviews and literature. Different methods of attaining the organic waste were reviewed and the options for biogas production were evaluated by comparing the highest investment cost admissible for a positive netpresent value of a prospective investment with estimations of investment costs from literature sources. Small-scale decentralized biogas production was found to be the most economically and socially viable option. For centralized production, the results were inconclusive but indicated the potential of profitable business cases. It is estimated that wet digestion in a floating-drum ortubular digester is most suitable for small scale applications while acontinuously dry digestion system is best suited for large scale biogasproduction in Curitiba. The sensitivity analysis showed that the amount oforganic waste available as well as the price of sold products had the biggest economic impact in the scenarios. It was found that any implementation of controlled anaerobic digestion would decrease the total global warming potential of the waste management system. It is recommended that the municipality proceed with and expand a pilot project at Mercado Regional, as well as exploring possibilities for more efficient waste collection, along with gathering more specific data on compositions and quantities for different waste flows. The study was carried out in the scope of a cooperation between KTH, the Swedish EnvironmentalProtection Agency, Municipality of Curitiba and local universities in Paraná,Brazil.Den brasilianska staden Curitiba producerardagligen 2 500 ton MSW (municipal solid waste) som i dagsläget deponeras. Isyfte att hitta en mer hållbar lösning för avfallshantering ämnade denna studieundersöka potentialen för biogasproduktion via rötning genom att analyseragenomförbarheten av småskalig decentraliserad biogasproduktion samtcentraliserad produktion i kommersiell skala. En fältstudie genomfördes för attkartlägga specifika lokala omständigheter och samla in data genom intervjueroch litteratur. Olika metoder för insamling av organiskt avfall granskades ochalternativen för biogasproduktion utvärderades genom att jämföra de högstatillåtna investeringskostnaderna för ett positivt nettonuvärde av en framtidainvestering med uppskattade investeringskostnader från litteraturkällor.Småskalig decentraliserad biogasproduktion visade sig vara det bästaalternativet från ett ekonomiskt och socialt perspektiv. För centraliseradproduktion var resultaten tvetydiga men indikerade att en lönsam affärsmodellpotentiellt kunde utarbetas. Rötning av substrat med hög fuktighetshalt i en“floating-drum” reaktor eller en tub-formad reaktor bedöms vara bäst lämpat förbiogasproduktion i liten skala emedan ett kontinuerligt system för rötning avtorra substrat bedöms som det bästa alternativet för storskaligbiogasproduktion. Känslighetsanalysen visade att mängden insamlat organisktavfall samt priset på slutprodukterna hade störst påverkan på det ekonomiskautfallet. Studien påvisade även att en implementering av en rötningsanläggningskulle minska växthuspotentialen i avfallshanteringssystemet oavsett skala. Detrekommenderas att kommunen fortsätter med och utvecklar ett pilotprojekt iMercado Regional, samt undersöker möjligheterna för effektivare sophämtning ochsamlar mer specifika data om sammansättning och kvantitet för olika sopflöden. Arbetetutfördes som ett led i samarbetet mellan KTH, svenska Naturvårdsverket,Curitiba kommun och lokala universitet i Paraná, Brasilien.
12
Rodriguez, Chiang Lourdes Maria. "Methane potential of sewage sludge to increase biogas production." Thesis, KTH, VA-teknik, Vatten, Avlopp och Avfall, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96294.
Full textAbstract:
Sewage sludge is treated with the biological process of anaerobic digestion in which organic material of a substrate is degraded by microorganisms in the absence of oxygen. The result of this degradation is biogas, a mixture mainly of methane and carbon dioxide. Biochemical Methane Potential tests are used to provide a measure of the anaerobic degradability of a given substrate. This study aims to determine the methane potential in Sjöstadsverket’s sludge this will moreover determine the viability of recycling the digested sludge back into the anaerobic system for further digestion. Batch digestion tests were performed in both Sjöstadsverket’s (S1) and Henriksdal’s (H2) sludge, for a reliable comparison. An inoculum to substrate ratio of 2:1 based on VS content was used and BMP tests presented results that S1 and H2 in the 20 days of incubation produced 0.29 NLCH4/gVS and 0.33 NLCH4/gVS respectively. A second experiment considering the same amount of substrate (200ml) and inoculum (200ml) for each sample, showed that Control S1 had a higher methane potential than Control H2, 0.31 NL/gVS and 0.29 NL/gVS respectively. All the samples containing Sjöstadsverket’s inoculum presented a higher volume of total accumulated gas (measured in Normal Liters), however methane potentials are low. Results demonstrated that methane production in samples S1 and Control S1 was originating from the grams of VS in the inoculum itself after depletion of all the soluble organic material in the substrate. This suggested that Sjöstadsverket’s sludge can endure a higher organic load rate and that the digested sludge still has potential to produce biogas, hence the recycling of this can enhance the biogas production in the digestion system.
13
Wang, Dongcan. "Comparative analysis of development potential for biomass- vs coal-fired powerplants in Henan province,China." Thesis, KTH, Energiteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211707.
Full textAbstract:
Coal-fired power plants’ typically large capacity and relatively low electricity generation costs in the Chinese power market can be compared with their typically low specific thermal efficiency and older age on average. At the same time, the environment pollution caused by local coal-fired power plants has started to receive due attention. Sustainable renewable energy sources and the application of effective conversion technologies for those has become a top priority of China's current energy strategy. Biomass in general and anaerobic biogas in particular can be regarded as clean, locally available renewable energy resources. Replacing coal with biomass-derived energy is especially relevant for certain locations in China. For the case of Henan province, work has already been undertaken by the local authorities for the proper estimation of the biomass potential and the selection of most applicable energy conversion technologies with the lowest environmental footprint to replace aging coal-fired plants with various biomass-based power generation facilities.Kolkraftverkens typiska stora kapacitet och relativt låga elproduktionskostnader på den kinesiska elmarknaden kan jämföras med deras typiskt låga specifika verkningsgrader och äldre ålder i genomsnitt. Samtidigt har miljöföroreningarna som orsakas av lokala kolkraftverk börjat uppmärksammas på riktigt i Kina. Hållbara förnybara energikällor och tillämpningen av effektiv konverteringsteknik för dessa har blivit en topprioritet för Kinas nuvarande energistrategi. Biomassa i allmänhet och anaerobisk biogas (rötgas) i synnerhet kan betraktas som rena och lokalt tillgängliga förnybara energiresurser. Byte av kol mot biobränslen blir särskilt relevant för vissa platser i Kina. När det gäller Henanprovinsen har en del arbete redan gjorts av de lokala myndigheterna för en korrekt uppskattning av biomasspotentialen och en analys av de mest tillämpliga teknologier för omvandling av bioenergi med lägsta miljöpåverkan som ersätter åldrande koleldade anläggningar med olika biobränslen.
14
White, Jeanette. "Biogas generation potential of coconut copra in the anaerobic digestion process." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2011. http://hdl.handle.net/10092/5680.
Full textAbstract:
Pacific Island Countries (PICs) currently rely heavily on imported, expensive and unsustainable fossil fuels as their primary source for energy production. Establishing an alternative energy source from local resources would therefore have considerable benefits for many Island communities. Coconut copra is high in biodegradable organic carbon and is found growing abundantly in PICs. One alternative use for this local resource would potentially be the conversion of the coconut copra into a valuable and useful energy source through biological processes, such as anaerobic digestion.
The purpose of this research was to investigate the biogas generation potential of coconut copra as a carbon source using anaerobic digestion processes. Both batch and continuously stirred reactors (CSTRs) in addition to the environmental and operating variables that affect the production of biogas were investigated in order to optimize methane production and increase the overall conversion efficiencies of organic matter to methane.
The results suggest that coconut copra is amenable to anaerobic digestion due to the high theoretical methane yields from the substrate’s high lipid content. However, the optimal organic loading rate (OLR) was limited to within a narrow range of 3.6-6 g VS (2.4 - 4 g VS/L Reactor) for the batch reactors and a maximum of 0.420 L CH4/ g VS was achieved at an OLR of 3.6 g VS. OLRs exceeding 15 g VS resulted in low pH values and negligible methane production due to substrate overloading. High average methane yields of 0.708 L CH4/ g VS•day were also successfully achieved for the CSTRs and increased mixing was observed to have an improved effect on methane production. However, the addition of nitrogen and phosphorus supplements failed to increase biological activity and ultimately resulted in the accumulation of ammonia to concentrations toxic to methanogenic bacteria. The failure of an accelerated CSTR start-up procedure also reinforced the requirement for a gradual and steady acclimated period for anaerobic digestion of this particular substrate.
15
Norr, Patrik. "Analysis and assessment of biogas production potential in Sweden for 2050." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-393916.
Full textAbstract:
The world is about to shift from fossil fuel dependency to independency. The national agenda of Sweden has put forth future goals of becoming a zero net greenhouse gas emitter by the year 2045 and before that, having an 80 % fossil fuel independent transportation fleet by 2030. In order to achieve these goals, the form of energy used in the transport sector needs to be changed into a more renewable solution. Biogas could be part of the solution. The aim of this report has been to review earlier research regarding the future biogas potential in Sweden and to examine how realistic and practically feasible these are. Three of the substrates that has shown the highest future potential according to earlier research; energy crops, manure and black liquor has been chosen for investigating their future potential. Interviews was made with biogas researcher in Sweden as well as government employees working with biogas and other biofuels. Scenario building was another method used were the report have created four future scenarios with varying optimistically future economic and technical outcomes using more practical limitations and restrictions. The result was a combined future potential of between 0,42 – 77,54 TWh/annually from all three substrates using the values and information gathered from the interviewers regarding how to calculate the potential. The result shows that depending on how lucrative the future financial support systems and subsidies as well as how efficient the technical breakthroughs will be, biogas can become a large contributor to the transport sectors transition in becoming less fossil fuel dependent.
16
Msibi, Sunset Siphamandla. "Potential for domestic biogas as household energy supply in South Africa." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/57495.
Full textAbstract:
Domestic biogas technology is a clean, renewable form of energy that is accessible to lowincome
households through anaerobic digestion of readily available organic waste. The
objective of this desktop study was to determine the amount of biogas required for substitution
of conventional domestic fuels (fuelwood, paraffin and coal), to quantify the health benefits
from reduced indoor air pollution due to such a substitution and to evaluate the availability of
feedstock for adoption of domestic biogas technology in South Africa.
The energy demand by low?income South African households for cooking with fuelwood was
calculated to be 27 MJ/day and the total energy demand to be 68 MJ/day. Approximately 80%
of the total energy is used for cooking, water heating and space heating and approximately 20%
is used for lighting. To meet the energy demand for cooking (27 MJ/day) with fuelwood with a
thermal efficiency of 13%, it was calculated that 2 500 L/day/household of biogas is required
which is in line with studies conducted in India and China. In order to meet the total energy
demand of 68 MJ/day by low?income South African households, it was calculated that biogas of
approximately 6 250 L/day/household is required of which 5 000 L/day/household is used for
cooking, water heating and space heating and also 1 250 L/day/household for lighting. A
photovoltaic (PV) solar home system is recommended for lighting in rural households instead of
using the inefficient biogas lamps which often pose a safety risk to the household members.
Complete substitution of fuelwood used for cooking with 2 500 L of biogas per day results in
cost savings of R904 per household per annum which is 4.3% savings of the average household
income and translates to a gross national annual cost savings of approximately R 1.5 billion.
Complete substitution of fuelwood as a source of energy results in cost savings of R1 808 per
household per annum which is 8.6% of the household income and translates to a gross national
annual cost savings of R4 ? 5 billion.
In terms of burden of disease and mortalities, it was determined that fuelwood use in South
African households results in 702 790 and 22 365 attributable disability?adjusted life years
(DALYs) lost and mortalities respectively. It was also determined that 50% of the attributable
DALYs lost and mortalities from solid fuel use can be avoided by substitution of fuelwood used
for cooking with 2 500 L of biogas per day per household whereas complete substitution of
fuelwood with biogas can result in the avoidance of approximately 85.4% of total DALYs lost
and mortalities from solid fuel use.
It terms of feedstock availability, it was determined that there is potential for domestic biogas
technology utilising cattle and pigs waste as feedstock. Due to access to sufficient cattle dung, it
was determined that approximately 613 662 households can potentially benefit from 2 500
L/day capacity biogas digester installations fed with cattle dung. Approximately 131 392
households can potentially benefit from 5 000 or 6 250 L/day capacity biogas digester
installations fed with cattle dung. The number of households that have access to sufficient pigs
waste to benefit from installations of 2 500 or 5 000 or 6 250 L/day capacity biogas digesters
fed with pig waste are 12 089. Due to the number of chickens required and the average number
of chickens kept by South African households, it can be deduced that it is not feasible to
operate a biogas digester fed solely with chicken waste. It was also determined that South
African households do not generate sufficient human excreta and food waste to feed a biogas
digester of a sufficiently large size. It is therefore recommended that community digesters in
peri?urban areas/informal settlements be co?fed with 1:1 mixture of sewage and food waste. It
is also recommended that the households interchangeably utilize the biogas from the
community digester for cooking purposes.
Non?sewered households with access to on?site water supply generate sufficient greywater for
feeding a domestic biogas digester. This is therefore recommended over drinking water. Nonsewered
households with access to off?site water supply generate insufficient greywater for
feeding biogas digesters of 5 000 L/day and 6 250 L/day capacity. It is therefore recommended
that in non?sewered households with access to off?site water supply greywater be augmented
with harvested storm water or water from nearby rivers, dams and streams.
Since the present work is a desktop study, it is recommended that a pilot scale study be
launched to confirm the findings of this study regarding the quantity of biogas required to
substitute conventional domestic fuels as well as the feasibility of domestic biogas technology
in low?income South African households or at community level.Dissertation (MSc)--University of Pretoria, 2015.
tm2016
Chemical Engineering
MSc
Unrestricted
17
Tcha-Thom, Maglwa. "Recherche d'une filière durable pour la méthanisation des déchets de fruits et d'abattoirs du Togo : Evaluation du potentiel agronomique des digestats sur les sols de la région de la Kara." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0061/document.
Full textAbstract:
La digestion anaérobie, procédé d’énergie renouvelable, constitue un atout indéniable de récupération des flux matière et énergie des déchets en réponse aux enjeux du développement durable. Ainsi, la présente étude a pour objectif de contribuer à la compréhension des mécanismes qui gouvernent l’environnement réactionnel de digestion en anaérobie et les effets des digestats sur la matrice bio-physico-chimique des sols à vocation agricole. Le développement des tests de lixiviation en réacteurs contrôlés aérobie et anaérobie, les modes de mobilisation du contenu organo-minéral des substrats et la valorisation du biogaz pour l’équarrissage des bêtes ont été réalisés. Les verrous techniques et physico-chimiques entachant la digestion anaérobie des déchets d’ananas ont été levés et optimisés grâce à des co-substrats notamment les bouses de vache et les cendres. Les digestats ont été apportés sur des sols agricoles, des sols des zones de forêts et des milieux sans matière organique ni argiles et ont permis de déceler les limites d’utilisation des digestats et les interactions avec les fractions organiques et minérales du sol. Cette étude montre ainsi, l’importance de développer la filière de méthanisation pour une élimination durable des déchets organiquesAnaerobic digestion, a renewal energy process, constitutes an undeniable asset of material and energy flows recovering in response to sustainable development issues. Thus, the aim of this current study was to contribute to the understanding of mechanisms that govern the reactive environment of anaerobic digestion and the effects of digestates on the biophysico- chemical matrix of agricultural soils sector. The running of leaching tests in aerobic and anaerobic controlled reactors, organo-mineral mobilizations patterns of the substrates and the valorization of biogas in slaughtered animals knackering have been realized. The physicochemical and technical locks tarnishing the pineapple wastes anaerobic digestion have been lifted and optimized through the co-substrates including cattle manure and ashes. The digestates have been brought on agricultural soils, forests areas soils and medium free of organic matter and clays and allowed to detect the limits of digestates uses and the interactions with organic and mineral fractions of soils. This study, thus show, the importance to develop the anaerobic digestion sector for a sustainable removal of organic wastes
18
Wistrand, Rickard. "Biogas ett alternativt fordonsbränsle : Nyckelfaktorer för utveckling och ökat användande." Thesis, Department of Thematic Studies, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-967.
Full textAbstract:
Dagens samhälle är beroende av olja i olika former, och det råder stor osäkerhet om hur länge oljan kommer att räcka i den takt som den förbrukas idag. 1997 utarbetades Kyoto-överenskommelsen för att minska utsläppen av koldioxid. Under år 2003 kom EU: s biodrivmedelsdirektiv 2003/30, som sätter upp riktlinjer för ett ökat användande av alternativa bränslen.
Mitt syfte har varit att åskådliggöra biogasens framtida potential för som ett alternativtbränsle till bensin och diesel, samt att undersöka vad som krävs och vad som görs för att öka biogasproduktionen för att få ett utökat användande för att uppnå målen med EU: s biodrivmedelsdirektiv 2003/30. Uppsatsen har byggts på intervjuer med representanter från SvenskBiogas, Energimyndigheten, Svenskt Gastekniskt Center och JTI (Institutet för jordbruks- och miljöteknik). Vidare har även biodrivmedelsdirektivet legat till grund i uppsatsen, samt vetenskapliga artiklar och ett antal forskningsrapporter som har använts för att underbygga resultaten i uppsatsen.
Resultatet i uppsatsen visade att den teoretiska framtida potentialen för biogasdrivna fordon, kommer att ligga någonstans mellan 10-17 TWh/år. Dessa beräkningar förutsätter att jordbrukssektorn är villig att odla grödor på den mark som ligger i träda, samt är beroende av hur stor andel av restprodukter från de övriga delarna av jordbrukssektorn som samlas in. Om enbart odlingar av marken som ligger i träda inkluderas, kommer biogas motsvarande 10-12 TWh/år produceras, vilket skulle motsvara 15 % av allt fordonsbränsle. Dessa substrat kan komma att börja användas i större skala längre fram i tiden. Men på kortare sikt är det framför allt avfall från slakterier, restauranger och till viss del jordbrukssektorn som kommer att ligga till grund för att uppnå målen med biodirektivet. Effektiviseringar är något som bör göras för att öka effektiviteten, säkerheten och mängden producerad biogas. Resultatet visade också att hushållsavfall eventuellt kommer att bli intressant att börja röta i större skala för att öka biogasproduktionen.
Rötning av restprodukter och av andra biologiska substrat genererar stora mängder rötrester som bör komma tillbaka till åkrarna, eftersom den innehåller mycket näring som skulle kunna användas på åkrarna som jordförbättringsmedel. Generellt sett rötas olika substrat samtidigt i dagens anläggningar, vilket genererar en rötrest som kan innehålla ämnen som är skadliga och inte bör komma ut på åkrarna. Detta medför att bönderna inte vill använda det. Problemet måste lösas (på något sätt) innan den eventuella biogasproduktionen av grödor från jordbrukssektorn kan starta i större skala, vilket också gäller rötning av hushållsavfall.
En slutsats som kan dras är att om den nämnda biogasproduktionsökningen ska kunna genomföras, kommer inställningen hos staten, länsstyrelserna och kommunerna ha stor betydelse. Framför allt kommer jordbrukssektorns inställning bli avgörande. På lite längre sikt kommer även allmänhetens inställning till en utökad biogasproduktion komma att vara av stor betydelse eftersom det är där hushållsavfallet finns.
19
Malmros, Peter. "Biogaspotential hos rejektfraktionen från biogasanläggningen Kungsängens gård." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-157977.
Full textAbstract:
Den totala biogasproduktionen i Sverige 2009 var 1,4 TWh och 22 % av biogasen producerades i samrötningsanläggningar. Sedan 2005 är det förbjudet att deponera organiskt avfall, vilket har gjort att produktionen från samrötningsanläggningar har ökat de senaste åren. Den totala biogaspotentialen i Sverige är ungefär 15 TWh och där står lantbruket för över 70 %. Avloppsslam, avfall från livsmedelsindustrin och matavfall står för den resterande delen. Det är även dessa tre råvarugrupper som har störst lönsamhet med dagens teknik. Av dessa råvarugrupper finns den största kvarvarande potentialen hos matavfall. Problemet med matavfall är att det ofta innehåller föroreningar som måste sorteras bort för att inte orsaka driftstörningar. Detta orsakar ofta problem på grund av att organiskt material hamnar i rejektet. Kungsängens gård är en samrötningsanläggning som producerar biogas från olika typer av organiska restprodukter. Under 2009 behandlades 7 536 ton material, av detta var 58 % matavfall. Av inkommande material sorterades 938 ton ut och lämnade anläggningen som rejekt. Under 2011 förväntas mängden inkommande material öka. Dessutom förväntas andelen matavfall öka till 90 % vilket kommer att ge ännu större rejektmängder. Syftet med detta examensarbete var att genom analyser och satsvisa utrötningsförsök bestämma den kemiska sammansättningen samt metanpotentialen hos de olika rejektfraktionerna från biogasanläggningen Kungsängens gård. En utredning gjordes för att undersöka vilka möjligheter och tekniker som potentiellt skulle kunna användas för att framställa biogas av rejektet och också vilka möjligheter som finns för att effektivisera befintlig utrustning. Resultatet från utrötningsförsöken visade att metanpotentialen för de olika rejektfraktionerna var hög och kan jämföras med vad som kan förväntas av källsorterat matavfall. Om rejektet som producerades under 2010 skulle användas för biogasproduktion skulle denna metanpotential motsvara 10 % av den totala biogasproduktionen vid Kungsängens gård under 2010. Utredningen visar att det bästa alternativet för att röta rejektet i sitt befintliga skick är satsvis torrötning. Osäkerheten kring torrötning är dock stor på grund av att det i Sverige inte finns några torrötningsanläggningar och därmed är kunskapsnivån relativt låg.The biogas production in Sweden in 2009 was 1,4 TWh and 22 % of the biogas was produced in co-digestion plants. Since 2005 it is prohibited to deposit organic waste and this has resulted in an increased biogas production from this type of waste materials in recent years. The total biogas potential in Sweden is approximately 15 TWh and 70 % of that comes from agriculture wastes. Sewage sludge, waste from food industry and food waste accounts for the rest. It is also these three commodity groups that have the greatest profitability with today's technology. Among these groups, food waste have the largest remaining biogas potential. The problem with food waste is that it often contains impurities that must be sorted out in order to avoid operational problems. The out sorting process often causes problems and typically organic material is lost in the reject fraction. The biogas plant Kungsängens gård is a co-digestion plant that produces biogas from different types of organic residues. In 2009 about 7 536 tons of material were treated, of which 58 % was food waste. Of the incoming material 938 tons were sorted out as reject. In 2011 the amount of incoming material is expected to increase. In addition, the proportion of food waste is expected to increase to 90 %, which will result in even larger amounts of reject. The purpose of this study was to perform analysis and batch digestion experiments to determine the chemical composition and methane potential of the reject from the biogas plant Kungsängens gård. An investigation was also made to examine methods and technologies that potentially could be used to produce biogas from the reject. The results from the batch digestion experiments showed that the methane potential of the different reject fractions was high and it can be compared with what might be expected of source separated food waste. If the reject that was produced in 2010 would be used for biogas production, this methane potential is equal to 10 % of the total production of biogas at Kungsängens gård in 2010. The investigation shows that dry fermentation with a batch system is the only technology that potentially could produce biogas from the reject in its existing form. There are no dry fermentation plants in Sweden and therefore the level of knowledge is relatively low. Because of that it is hard to estimate the profitability and efficiency of dry fermentation plants.
20
Ffolliott, Peter F., Wayne T. Swank, William H. Banzhaf, David R. Betters, Warren P. Clary, J. W. McMinn, and W. H. McNab. "Potentials of Noncommercial Forest Biomass for Energy." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/310782.
Full text
21
Kiesel, Andreas [Verfasser], and Iris [Akademischer Betreuer] Lewandowski. "The potential of miscanthus as biogas feedstock / Andreas Kiesel ; Betreuer: Iris Lewandowski." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2020. http://d-nb.info/1212509382/34.
Full text
22
Olivas, Nathaniel Manuel. "Two-Phase Anaerobic Digestion to Reduce the NOx Emission Potential of Biogas." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1516.
Full textAbstract:
Anaerobic digestion can be used to decrease the mass of organic wastes to be disposed of while producing useful biogas (CH4 and CO2) for heat or power production, but in air basins with strict emissions limits, biogas combustion is difficult to implement due to the high costs of controlling NOx emissions. NOx production can be minimized by blending H2 gas with CH4 at a volume ratio of 15:85 H2:CH4, which allows burning at ultra-lean air-to-fuel ratios. For biogas systems, a potential low-cost NOx control strategy is to produce H2-CH4 mixtures through two-phase anaerobic digestion, where two digester tanks are operated in series, with the first one producing a majority H2 and the second CH4. The resulting mixture of H2, CH4, and CO2 should combust with low NOx emissions. Furthermore, in theory, if the biogas from the second-phase is sparged through the first-phase, H2 would be stripped from the first-phase liquid medium, and H2 production would be more thermodynamically favored, possibly increasing H2 production.
Laboratory experiments were used to determine the optimal conditions to generate biogas with a 15:85 H2:CH4 ratio using two phase digestion with glucose as the substrate. Specifically, the objectives of this thesis were to (1) determine the optimal conditions for operating the first-phase to produce H2, (2) determine the sparging rate required to achieve 15:85 H2:CH4 in the biogas, and (3) operate the first and second-phases together with second-phase biogas being sparged through first-phase medium to achieve 15:85 H2:CH4. The results from each of these objectives are described below.
(1) The optimal conditions for H2 production in the first-phase were an organic loading rate of 22.9 g COD/L-day (chemical oxygen demand) and a hydraulic residence time of 12 hours. The resulting pH in the first-phase was 6.11 when operated under these conditions. Optimized hydrogen production in the first phase resulted in the generation of 1.02 ± 0.13 L H2/Ldigester-day, which can also be expressed as 0.61 ± 0.10 mol H2/mol glucoseconsumed, 0.42 ± 0.06 mol H2/mol glucoseintroduced, 1.06 ± 0.16 mol H2/mol CODdestroyed, and 0.06 ± 0.01 mol H2/mol CODintroduced.
(2) Initial sparging experiments were conducted using nitrogen (N2) to represent second-phase biogas. The rates tested ranged from 1- 30 L N2/Lfirst-phase digester-hr. A 1.1 L gas/L-hr sparging rate was projected to result in a 15:85 H2:CH4 ratio. The projection was made using a power regression model (R2 = 0.99) of sparging rate vs. hydrogen content results, assuming the sparged N2 was replaced with typical biogas (60% CH4 and 40% CO2).
(3) When both phases were integrated, the second-phase produced enough gas to sparge at only 0.28 L gas/Lfirst-phase digester-hr, which was far less than the optimal 1.1 L gas/Lfirst-phase digester-hr sparging rate. A non-optimal H2:CH4 ratio of 15:12 was obtained at the 0.28 L gas/L-hr sparging rate. Insufficient CH4 was generated due to the low organic loading provided to the second-phase.
Although the 1.1 L gas/L-hr sparging rate was not tested in an integrated system, the results obtained from the 0.28 L gas/L-hr sparging rate differed from what was predicted by the nitrogen sparging model by only 14%. Therefore, the model was fairly accurate (at least at a low flow rate of 0.28 L gas/L-hr) and could still be valid for the predicted optimal flow rate of 1.1 L gas/L-hr.
For future two-phase digestion studies, biogas production from the second-phase can be increased by adding more substrate to the second-phase or by using fixed-film digesters to possibly increase the number density of methanogens. It is also recommended to digest practical waste feedstocks, and possibly digest different feedstocks in the first and second-phases. Also, the effects of carbon dioxide on the combustion characteristics and NOx emissions of hydrogen-methane mixtures in biogas need to be researched.
23
Hansen, David. "Beskrivning av Kolmårdens stallgödsel : Hantering och biogaspotential." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-24433.
Full textAbstract:
Stallgödsel består av spillning, gödselvatten, urin och strömaterial. Miljö- och hälsoskadliga ämnen kan också förekomma i form av antibiotikarester eller patogener. Det är därför viktigt att gödselhanteringen sköts på korrekt sätt för att undvika att de skadliga ämnena vållar miljö- och hälsoproblem. Naturliga ämnen som kväve och fosfor förekommer också i stallgödsel bidrar till miljöeffekter som övergödning eller försurning vid felaktig gödselhantering. Miljöeffekterna drabbar i sin tur ekosystem och de konsekvenser som uppstår är bland andra fiskdöd och giftalgblomningar i vattendrag. Examensarbetet kommer att belysa de ekologiska och sociala fördelarna som Kolmården skulle kunna erhålla om de byter gödselhanteringssystem från gödselspridning till rötning. Dessutom kommer Kolmårdens nuvarande stallgödselhantering att beskrivas, aspekter som kan påverka biogaspotentialen att presenteras och den teoretiska mängden biogas som kan utvinnas ur stallgödseln att beräknas. Det första som genomfördes i examensarbetet var att dela in Kolmårdens djur i olika djurgrupper för att kunna utföra beräkningar på biogaspotentialen. Totalt tre djurgrupper figurerar i examensarbetet och de är: fågel, icke-idisslare och idisslare samt allätare och rovdjur När djuruppdelningen var slutförd påbörjades litteraturstudien för att få fram aktuellt material att använda i studien och förbereda de intervjufrågor som sedan användes i samband med ett studiebesök på Kolmården. Stallgödseln som uppkommer i djurparken mockas från djurens hägn och stall varje dag för att sedan lagras på mindre gödselplattor. Dessa töms sedan tre gånger i veckan av entreprenörer som fraktar stallgödseln till en central gödselplatta innan den sprids på arrenderad mark eller överförs till en lantbruksentreprenör. Stallgödseln på Kolmården har teoretisk sett en potential att kunna täcka nära hälften av djurparkens årliga energibehov. Aspekter som påverkar biogasutbytet är föda, strömaterial, näringsinnehåll och antibiotika.Manure consist of feces, manure water, urine and stray material. Environmental and health harmful substances can also occur in manure. That is why it is important that the manure management is handled in a correct way to avoid the harmful substances that are likely to cause environmental and health problems. Natural substances are also a part of the manure and those are nitrogen and phosphorus and they could cause environmental effects as eutrophication and acidification with insufficient manure management. The environmental effects could affect ecosystems and the consequences could appear as that fishes are dying and poisonous algal blooms in watercourses. The bachelor thesis will illustrate the ecological and social benefits that Kolmården could achieve if they are replacing the current manure management which is manure spreading with anaerobic digestion. Besides that the current manure management will be described in more depth, aspects that could affect the biogas potential will be presented and the theoretical amount of biogas of the manure will be calculated. The first step that was completed in the thesis were to divide Kolmården’s animals into different animal groups that later could be used in the calculations of the biogas potential. Totally there are three animal groups in this thesis and they are: fowl, non-ruminant and omnivore and beast of prey. When dividing the animals was completed the search for literature began with the purpose to get up-to-date material that could be used in the thesis and to prepare the interview questions for the study visit at Kolmården. The amount of manure that emerge in the zoo is mucked from the animal’s pens and stables every day to be stored in small manure storage places. Those are emptied three times a week and freighted to a central storage place before the manure is spread on tenancy land or transferred to a farmer. The theoretical biogas potential from the manure at Kolmården can cover almost half of the energy need in a year. Aspects as food, straw material, nutrition content and antibiotics can affect the biogas yield.
24
Alander, Johanna, and Adam Nylin. "Feasibility study for producing and using biogas in Chisinau, Moldova." Thesis, Linköpings universitet, Industriell miljöteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157694.
Full textAbstract:
More and more people live in cities, cities that both present opportunities, in terms of potential sustainable growth and challenges, for example regarding insufficient infrastructure and waste management. There are several examples on initiatives to make cities reach their sustainability potential; one is to turn municipal organic waste, MOW, and sewage sludge into biogas and use it to produce electricity and/or heat or to upgrade it to biomethane and use it as a fuel in for example public transport or feed it to a gas grid. This study has focused on the potential and feasibility of producing and using biogas/biomethane as well as the remains from the production process, called digestate, in Chisinau, the capital of Moldova. For the most feasible options an indication of the environmental improvement and economic performance was also estimated. The study included biogas produced from municipal organic waste, sewage sludge and methane collected at landfills. For the areas of use, electricity or heat produced from biogas was included as well as using biomethane in public transport or feeding it to the gas grid and to use the digestate as biofertilizer. Since multiple factors needs to be considered in order to adequately assess the potential and feasibility a multi-criteria approach was used for developing a framework based on an early assessment tool for biomethane solutions in the urban context. In summary it is indicated that there are good conditions for biogas production in Chisinau with biogas production from sewage sludge being included in the ongoing rehabilitation of the largest wastewater facility and methane collection from the largest landfill historically being part of the operations and planned (although not confirmed) to soon be part of these again. However, the largest potential is for municipal organic waste where the main impediments relates to financial issues and to some extent legislation that indirectly favour short term landfilling. When investigating the possible use of the digestate as biofertilizer the outlooks are considerably less promising than for the supply side. Despite the fact that the law explicitly allows the use of digestate (both from MOW and sewage sludge) the lack of knowledge within the farmer community result in a low or non-existent customer demand. Regarding the possible use of biogas/biomethane it was concluded that electricity production is the most feasible option and heat generation placing as the second most feasible. Feeding the gas to the grid appears more difficult and the least likely option is for the biogas to be used within public transport. Overall it is in general technically possible to use the gas in terms of infrastructure and there is some demand, especially for electricity and heat. The biggest inhibitory factors are rather institutional since biogas in general is overlooked or not prioritized in the strategies leading to a shortcoming in economical instruments or funds and to some extent in the legislation. This thesis is complemented by an executive summary with the same name, both in English and translated to Romanian.
25
Wollak, Birte. "Determination of the methane potential of blue mussels." Thesis, Linnéuniversitetet, Institutionen för bygg- och energiteknik (BE), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-27098.
Full textAbstract:
The aim of this study was to evaluate the methane potential of 35 kg of blue mussels in a batch amanaerobic two-stage dry digestion system (pilot-scale), which consists of aleach bed reactor (LB) and an up-flow anaerobic sludge blanket reactor (UASB). We monitored the process daily by measuring temperature, pH, COD, VFA, NH4+ gas flow rate and gas content. The temperature was approximately 30 C in the LB and 36 C in the UASB reactor. The applied OLR was 1.5 g COD/l*d. After 37 days process run, we obtained a total methamne yield of 0.64 Nm3 respectively 0.29 Nm3/kg VS, of that 70% in the LB reactor and 30% in the UASB reactor.
26
Lönnqvist, Tomas. "Biogas in Swedish transport – a policy-driven systemic transition." Doctoral thesis, KTH, Energiprocesser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206578.
Full textAbstract:
The thesis analyzes the conditions for biogas in the Swedish transport sector. Biogas can contribute to the achievement of Sweden’s ambitious targets of decreased emissions of greenhouse gases and an increased share of renewables in the transport sector, a sector that encompasses the major challenges in the phase-out of fossil fuels. Biogas development has stagnated during recent years and there are several factors that have contributed to this. The use of biogas in transport has developed in niches strongly affected by policy instruments and in this thesis, the progress is understood as a policy-driven systemic transition. Biogas has (started to) become established at the regime level and has begun to replace fossil fuels. The major obstacles for continued biogas development are found to be the stagnated vehicle gas demand, the low predictability of Swedish policy instruments, and electric car development. Moreover, the current prolonged period of low oil prices has also contributed to a lack of top-down pressure. A large share of the cheap and easily accessible feedstock for conventional biogas production is already utilized and an increased use of vehicle gas could enable a commercial introduction of forest-derived methane. However, the technologies to produce forest-derived methane are still not commercial, although there are industrial actors with technological know-how. Future biogas development depends on how the policy framework develops. Policy makers should consider the dynamics of biogas as a young sociotechnical system where different system fronts develop at a varying pace. Currently the demand side is lagging behind. However, it is necessary to maintain predictable policy support throughout the entire biogas value chain, since the system fronts that lag can vary over time. The low predictability of Swedish policy instruments indicates that policy makers should exercise care in their design to create a more robust policy framework moving forward.QC 20170508
27
Mezzullo, William G. "An interdisciplinary assessment of biogas production and the bioenergy potential within the South West of England." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527139.
Full textAbstract:
There is a growing need to reduce the use of fossil fuels for energy. A twofold reason exists for this: firstly these resources are finite; secondly the utilisation of these resources releases greenhouse gases which are known to contribute towards climate change. The rise in global population and energy use per person is adding to the unsustainable use of fossil fuels. There is the potential to reduce fossil fuel consumption in the South West of England. The region’s abundant natural resources could be used to reduce the overreliance on energy from fossil fuels. A key natural and renewable resource within the region is the availability of biomass. Bioenergy is a form of energy, derived from biomass. Bioenergy has the capability to displace the use of fossil fuels. Additionally, it has the potential to reduce the effect of climate change by absorbing carbon dioxide during the biomass production period. It has the possibility of being integrated into existing infrastructure and is one of the few renewable technologies which can satisfy an array of end-use energy requirements. This thesis highlights a unique method of assessing the potential of bioenergy in the South West of England using a multi appraisal technique. The initial assessment within this thesis has examined the resource availability of bioenergy based on biomass feedstock. Whilst quantifying the overall availability, constraints have been examined to determine the realisable potential of biomass as an energy source. The analysis has then assessed the drivers and barriers of bioenergy development within the region and contextualised this for the UK in general. Following the selection of a single bioenergy pathway (biogas production from anaerobic digestion), the technology has been assessed using a multi appraisal methodology. This methodology has involved the use of net-energy analysis, environmental life cycle assessment and financial investment assessments. The thesis demonstrates that the region has a notable resource availability of biomass. However, a number of barriers to development have been found which could impede the utilisation of this energy source. The selected bioenergy pathway of biogas from anaerobic digestion was found to eliminate some of these barriers. Assessing the potential of biogas using multi appraisal techniques highlighted that this pathway could, in some cases, offer positive environmental, energy and financial benefits.
28
Tesfaye, Tefera Tadious. "Potential for biogas production fromslaughter houses residues in Bolivia : Systematic approach and solutions to problems related to biogas production at psychrophilic temperature." Thesis, KTH, Energi och klimatstudier, ECS, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48101.
Full textAbstract:
Residues from slaughter houses offer an abundant resource in Bolivia. The residues can beused for biogas production with biofertilizer as a bi-product. These resources are, however,currently not being used. Instead, they are released in water systems, implying heavycontamination, e.g., on the Lake Titicaca in western Bolivia. Severe environmental effects areobserved in the lake and connected water systems. The residues from slaughter houses are animportant part of the problem. If the contamination continues, important environmental values willbe lost. Information around the resource is scarce, since no extensive inventory has been carried out. It isestimated that officially registered slaughter houses in the four major cities of Bolivia aloneproduce over 75 tons of organic residues per day. This flow of residues has increased since theworld market for animal fodder based on blood dropped significantly. In addition, there is littleexperience of biogas production in cold environments at that altitude, almost4000 meters over sea level. Production of biogas from waste is one of the most common methods to generate energy and at thesame time best waste reduction methods. Biogas production can be practiced favoring one theextremities, that is, either for the purpose of energy production or waste reduction. In this thesis, the focus is on waste reduction, that is the slaughter houseresidues. Nevertheless, the ultimate outcome is always to reduce as much waste as possible and, atthe same time, generate profitable energy. There are many technological and financial challenges that have to be addressed to see the completerealization of the biogas concept. Therefore, this master thesis focus on producing biogas fromresidues of slaughter houses in the greater area around Lake Titicaca and studies whichtechnological issues have to be solved. Furthermore, analyzing how the biogas segment can befurther developed in Bolivia according to the appropriate technology selection is alsoinvestigated.
29
Duong, Sutina. "Systematic Assessment of Straw as Potential Biogas Substrate in Co-digestion with Manure." Thesis, Linköpings universitet, Industriell miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-111438.
Full textAbstract:
This work was carried out at Biogas Research Center (BRC) and the company Biogas in Vadstena. The aim was to systematically evaluate new substrates for biogas production. In particular, this case investigated the potential of straw in co-digestion with manure and slurry from pig, chicken and dairy. Straw is interesting to evaluate since it is second generation biomass and available in a large quantity. Also, anaerobic digestion (AD) of manure is beneficial because it deals with the spontaneous methane emission and leads to a better manure handling. Goals within the EU as well as in Sweden have been set up to reduce greenhouse gas emissions from fossil fuel and to produce more renewable energy. The methodology used is outlined by BRC in which a number of key areas, such as description of biomass, amount biomass, gas yield, technology, economy, environmental performance and energy system, competing interests and institutional factors, have been evaluated through literature studies and case study Biogas in Vadstena. Based on the results an overall judgment is done to determine the potential of straw. The result shows that straw is not appropriate to digest solely because of high TS, high carbon content and lack of nutrients. Straw also has lignocellulosic structures, which are difficult to break down. Especially lignin limits the biodegradability. Mechanical, thermal, chemical and biological pretreatments can increase the availability and biodegradability in the straw. In some cases pretreatment can also increase the methane potential. However, straw works well as a carbon complement in co-digestion with manure, which is a nitrogen-rich substrate. There are technologies available for AD of straw and manure for the whole biogas process, from transportation and pretreatment to digestion and upgrading. Although, there is space for further development of pretreatment and upgrading technology. The economic calculations show that it is profitable to use straw with manure in a farm-based biogas plant for vehicle gas production. Furthermore, the calculations of the energy show that biogas production is energy efficient with energy input/output ratio of 18-23%. Besides production of biogas, the digestate could be used as an environmentally friendly fertilizer. In summary, it is possible to produce biogas from straw together with manure, and this is beneficial from both an environmental and economic perspective.Detta examensarbete har utförts i samarbete med Biogas Research Center (BRC) och företaget Biogas i Vadstena. Målet med examensarbetet var att systematiskt utvärdera nya substrat för biogasproduktion. Specifikt för det här fallet var att undersöka potentialen för halm i samrötning med gödsel och flyt från svin, höns och nöt. Halm är intressant att utvärdera då det tillhör andra generationens biomassa och finns tillgängligt i stor mängd. Även rötning av gödsel är givande då den spontana metanemissionen uteblir och det ger en bättre gödselhantering. Det har satts upp mål inom såväl EU som i Sverige att mer förnybart bränsle bör produceras för att minska växthusgasutsläppen från fossila bränslen. Metodiken som använts har framarbetats av BRC. Det innebär att substrat granskas utifrån ett flertal nyckelområden, såsom beskrivning och mängd biomassa, gasutbyte, synergieffekter, teknik, ekonomi, miljöpåverkan och energisystem, konkurrerande intressen och institutionella faktorer. Dessa har utvärderats genom litteraturstudier och studie av fallet Biogas i Vadstena. Utifrån resultatet görs en övergripande bedömning av substratet. Resultatet visar att halm inte är lämpligt att röta enskilt på grund av högt TS-värde, högt kolinnehåll och att den är näringsfattig. Halm består även till stor del av lignocellosa-strukturer som är svåra att bryta ned, i synnerhet lignin. Mekaniska, termiska, kemiska och bioglogiska förbehandlingar kan öka tillgängligheten och nedbrytbarheten av halm. Det kan även öka metanpotentialen i vissa fall. Däremot fungerar halm bra som ett komplement i samrötning med gödsel som är ett kväverikt substrat. Det finns teknik för rötning av halm för hela biogasprocessen, från transport, förbehandling och rötning till uppgradering. Dock finns utrymme för tekniken att utvecklas ytterligare. De ekonomiska beräkningarna visar att det är lönsamt att använda halm tillsammans med gödsel i en jordbruksbaserad biogasanläggning för fordonsgasproduktion. Vidare visar beräkningar för energisystemet att biogasproduktion är energieffektiv med energi input/output-kvot på 18-23%. Förutom fordonsgas produceras även biogödsel som är ett miljövänligt alternativ till konstgjord gödsel. Sammanfattningsvis, det är möjligt att producera biogas av halm tillsammans med gödsel och det är fördelaktigt ur en såväl miljömässigt som ekonomiskt perspektiv.
30
Khorshidi, Kashani Azar. "Application of Various Pretreatment Methods to Enhance Biogas Potential of Waste Chicken Feathers." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19567.
Full textAbstract:
Chicken feathers are the most abundant keratinous biomass in the world. Disposal of thehuge and increasing volume of waste feathers presents as a major concern for poultryindustry. On the other hand, energy and material recovery of this valuable protein sourceis an important issue for organic solid waste treatment and bioenergy generation.Anaerobic digestion is an environmentally and economically promising alternativeprocess for biogas production of waste feathers.In this study in order to enhance the methane potential of batch anaerobic digestion ofchicken feathers this waste was treated by various kinds of pretreatments includingthermal, thermo-chemical, enzymatic, thermo-enzymatic and chemo-enzymatic methods.Also the effect of different treatment conditions on the methane yield was investigated.As a whole, thermo-chemical pretreatment with lime (Ca(OH)2) rendered the mostsignificant effect on enhancement of the chicken feathers methane potential. In particularlime treated triplicate samples under treatment condition of 40g TS feather/l water, 0.1gCa (OH)2 /g TS feather, 100°C and 30 min produced the highest amount of methane (anaverage maximum volume of 480 Nml/g VS, which is about 96.8% of the theoreticalmethane potential of protein), during 50 days of anaerobic incubation. Increasing theoperational parameters such as feather concentration, lime loading, temperature andreaction time improved the feathers solublisation resulting in a higher soluble chemicaloxygen demand (SCOD) concentration of the samples but inserted negative impacts onthe anaerobic digestion performance. Although other pretreatment methods improved theSCOD concentrations of the feathers too, compared to the lime treatment those methodsdidn’t show considerable effects on the enhancement of methane yield from the chickenfeathers. Thermo-enzymatic, enzymatic, and thermal pretreated triplicate samplesproduced an average maximum of 185 Nml/g VS, 154 Nml/g VS, and 143 Nml/g VS(37.3%, 31%, 28.8% of the theoretical methane potential) respectively, during 33 days of50 days of anaerobic incubation. Especially, chemo-enzymatic pretreated sample showednegative methane potential of only 41 Nml/g VS, i.e. 8% of the theoretical methanepotential. Consequently, lime pretreatment under the above recommended conditions canbe suggested for hydrolysis of chicken feathers to achieve significant enhancement of itsmethane potential.
31
Langley, Kyle Anthony. "Potential benefits and experienced challenges of small household biogas-digesters for rural households." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1021268.
Full textAbstract:
Access to renewable energy supplies is a critical foundation for sustainable development and poverty alleviation. Anaerobic biogas-digesters also referred to as bio-digesters, have been identified as one of the leading technologies with regards to assisting in improving energy access for remote rural areas that still remain dependent upon biomass usage. This thesis assesses the potential feasibility of bio-digesters for rural households in South Africa by focusing on the experiences of a remote and rural community in Eastern Cape. A standardised survey was used to capture household details and energy use patterns of households with 180 interviews being conducted. Field observations were also conducted on the five bio-digesters installed in the community over a three month period. Despite the predominance of electrification in the community, households were heavily reliant upon biomass in the form of fuelwood and cattle dung to supplement their energy needs. Households supplemented their energy usage with alternative energy sources such as LPG gas and paraffin, especially during periods when electricity was unavailable or deemed too expensive. Initial knowledge of bio-digester technology in the community was non-existent, however with the installation of bio-digesters within the targeted villages, social learning was observed. Despite low temperatures bio-digesters continued to function throughout the study period, though malfunctions did occur and gas production did not reach optimal levels. Primary challenges encountered were the lack of financial subsidies for wide-spread adoption; the limited technical capacity of the community to conduct repairs and minimal gas production due to a build-up of ligneous materials within the gas chamber of the bio-digesters. Bio-digesters were found to provide significant benefits for households and further studies into maximising their effectiveness for rural South African households are recommended.
32
Forkman, Tova. "Biogaspotential vid samrötningav mikroalger och blandslam från Västerås kommunala reningsverk." Thesis, Sveriges lantbruksuniversitet, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-232954.
Full textAbstract:
Because of the increasing trends in energy consumption and increased environmental awareness, greater focus has been placed on improvement and development of renewable energy sources. An already proven and accepted method is biogas production from anaerobic digestion at municipal wastewater treatment plants. In the waste water treatment process solid material and dissolved pollutants are separated from the water, forming a sludge. The sludge is separated from the process and stabilized during anaerobic digestion or aerobic aeration. Most often, mesophilic anaerobic digestion is used. Because of degradation by microorganisms, biogas with a high content of methane is formed during the digestion. To optimize the process different studies with co-digestion with sludge and other substrate have been made. It has been showed, in earlier research studies, that co-digestion with microalgae and sewage sludge results in a synergistic effect with increased biogas production. As the microalgae are microorganisms which use photosynthesis they contain stored energy from sun light. The stored energy will be available when the microalgae are digested in mesophilic conditions. In contrast to other biomass suitable for co-digestion microalgae have the advantage of being able to grow in waste water and reduce the pollutants in the water phase. Cultivation of microalgae will therefore not compete with the cultivation of food production and at the same time has the possibility to decrease the electricity- and heat consumption at the wastewater treatment plants. The aim of this study was to investigate how a possible synergetic effect between microalgae and sewage sludge effects the biogas production and the process stability. The microalgae was cultivated in municipal waste water from the WWTP in Umeå (Sweden) and the sludge was collected from the WWTP in Västerås (Sweden). The fermenters used was of the type DOLLY© and the active volume was 5 dm3. The temperature in the fermenters was kept at 37 °C and the study was divided into two periods. During the first period the hydraulic retention time was 15 days and the organic loading rate 2.4 g VS dm-3 d-1. During the second period the hydraulicretention time was kept at 10 days and the organic loading rate was 3.5 g VS dm-3 d-1. The result showed an increase with 54.6 % in methane production per reduced VS in the fermenter with co-digestion compared to the fermenter where only sludge was digested. Period one showed the highest increase. The result also showed a good process stability for both fermenters during the whole experiment. This study shows that there are reasons for continued investigations about co-digestion with microalgae and sewage sludge for an increased biogas production.På grund av ökande el- och värmeförbrukning och ökat miljöengagemang har större fokus lagts på förbättring och utveckling av förnyelsebara källor för el- och värmeproduktion. En redan beprövad och accepterad metod för framställning av förnyelsebar energi är från biogasproduktion vid kommunala reningsverk. Vid rening av avloppsvatten avskiljs fasta partiklar och lösta föroreningar och bildar ett slam som separeras från vattnet. Slammet kan sedan stabiliseras anaerobt genom rötning eller aerobt genom luftning. En ofta använd metod vid konventionella reningsverk är mesofil anaerob rötning. Vid rötningen bryts material ner av mikroorganismer och genererar biogas som framförallt innehåller metan och koldioxid. För att optimera en sådan process och därmed kunna utvinna mer gas har det tidigare undersökts hur samrötning med olika material påverkar biogasproduktionen. Det har visat sig i forskningsförsök att samrötning med mikroalger och orötat blandslam ger en synergieffekt och mer biogas produceras. Mikroalgerna innehåller lagrad energi från solljus, då de är fotosyntesiserande organismer. Den lagrade energin har visat sig bli tillgänglig vid mesofil anaerob nedbrytning. Till skillnad från annan biomassa som undersökts för samrötning kan mikroalgerna odlas på avloppsreningsverken och fungera som en del av reningsprocessen då mikroalgerna tar upp näringsämnen ur vattnet de växer i. På det sättet undviks konkurrens om odlingsmark för livsmedel och så blir reningsprocessen på avloppsreningsverken mer el- och värmeeffektiv. Syftet med studien var att undersöka om eventuell synergieffekt mellan mikroalgerna och slammet påverkar biogasproduktionen och processtabiliteten vid mesofil anaerob rötning. Mikroalgerna som användes var odlade på mekaniskt renat spillvatten från Umeås reningsverk och slammet som användes hämtades ifrån Västerås reningsverk. Rötkamrarna som användes var av modellen DOLLY© med en aktiv volym på 5 dm3. Temperaturen i rötkamrarna hölls kring 37°C och studien var uppdelad i två perioder. Under period ett var den hydrauliska uppehållstiden 15 dygn och den organiska belastningen 2,4 g VS dm-3 d-1, medan period två hade en hydraulisk uppehållstid på 10 dygn och en organisk belastning på 3,5 g VS dm-3 d-1. Resultaten visade att metangasproduktionen per tillförd mängd organiskt material var lägre vid samrötning jämfört med rötning av enbart slam. Metangasproduktionen per reducerad mängd organiskt material ökade med upp till 54,6 % vid samrötningen jämfört med rötning av enbart slam. Period ett gav upphov till den största ökningen. Processen hölls stabil även vid inblandning av mikroalger, under både period ett och två. Studien visar att det finns ett underlag för fortsatta studier kring samrötning av mikroalger och slam för en ökad biogasproduktion.
33
Gunnarsson, Helene. "Livscykelanalys: Förbränning av hushållsavfall kontra biogas : miljömässiga och ekonomiska perspektiv med utgångspunkt i Oskarshamns kommun." Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-27413.
Full textAbstract:
Är det möjligt att reducera utsläppen av växthusgaser och samtidigt nå en hållbar utveckling? Regionförbundet i Kalmar län antog utmaningen 2006 och är därmed en föregångsregion i arbetet med detta. Till år 2030 är målet att Kalmar län ska bli en fossilbränslefri region. Den största potentialen anses finnas inom nya alternativ till fordonsbränsle. Hushållens sopor innehåller organiskt matavfall som skulle kunna bli fordonsgas. Allt fler biogasmackar öppnas och gasen har vunnit framgång i takt med att kollektivtrafiken gjort satsningar. I Oskarshamns kommun sker i dagsläget ingen utsortering av organiskt matavfall. Hushållsavfallet skickas tillsammans med det organiska matavfallet till förbränning med energiutvinning i Linköping. Syftet med min studie är att göra en utvärdering av miljöpåverkan utifrån två scenarier; förbränning av allt hushållavfall jämfört med att producera biogas av matavfallet och förbränna resterande. Detta sett utifrån potentialen för området i Oskarshamns kommun. Syftet är även att titta på ekonomiska aspekter. Detta är en livscykelanalys där två metoder har använts, Global Warming Potential med ett 100 års perspektiv samt ReCiPe Endpoint. Den funktionella enheten är 1 ton hushållsavfall. Genom att röta det organiska hushållsavfallet och förbränna det övriga kan man minska miljöpåverkan till 74,6 % jämfört med att förbränna allt tillsammans. Växthusgaserna minskar då med 780 kg koldioxidekvivalenter per ton hushållsavfall. Den främsta miljövinsten blir i form av minskande klimatförändringar men att det fordrar ganska omfattande ekonomiska investeringar.Is it possible to reduce greenhouse gas emissions while achieving sustainable development? The Regional Council in Kalmar County accepted the challenge in 2006 and is thus a leading region in this work. By 2030, the goal is that Kalmar shall become a fossil fuel free region. The greatest potential is considered to be the new alternative to vehicle fuel. Household waste includes organic waste that could become fuel for vehicles. An increasing number of biogas stations have opened and the gas has been successful as the public transports have made investments. In Oskarshamn is there no current sorting of organic waste. Household waste is sent along with the organic food waste to incineration with energy recovery in Linköping. The purpose of my study is to evaluate the environmental impact based on two scenarios: the burning of all household waste compared to producing biogas from food waste and burn the remaining. This is seen by the potential of the area in Oskarshamn. Also examining the economic perspective there is. This is a LCA where two methods were used, the Global Warming Potential with a 100-year perspective and ReCiPe Endpoint. The functional unit is 1 ton of waste. By digesting the organic waste and burning the rest, one can reduce the environmental impact to 74, 6 % compared to burning it all. The greenhouse gases then will decrease by 780 kg carbon dioxide equivalent per ton household waste. The main environmental benefits are in terms of reducing climate change, but it requires quite a significant financial investment
34
Christiansson, Samuel. "Potentialen för spillvärmeuppvärmda växthus i Sverige : ur ett hållbarhetsperspektiv." Thesis, KTH, Centrum för hälsa och byggande, CHB, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-104312.
Full textAbstract:
Sammanfattning Denna studie är en delstudie i ett större växthusprojekt som drivs av KTH Centrum för Hälsa och Byggande i Haninge utanför Stockholm. Projektet inbegriper ett integrerat spillvärme- och växthussystem med besöks- och forskningsändamål, placerat i anslutning till en reningsanläggning och ett naturbruksgymnasium. Studiens primära syften är att undersöka spillvärmepotentialen och potentialen för uppvärmning av växthus med spillvärme i Sverige. De sekundära syftena är att undersöka vilka hållbarhetsaspekter som kan identifieras som viktiga för spillvärme-växthus-system och att göra en idé- och informationssammanställning för dem som vill bygga spillvärme-växthus-system, med bland annat tips om hur produktpriser kan beräknas, vilka nyckeltal som kan användas för energikalkyler och vilka användningsområden som finns med ett växthus. Rapporten får ett visst fokus på livsmedels- och tomatodling, eftersom både tidigare studier och den fallstudie som ingår i rapporten handlade om detta. Studiens avsikt är dock att förespråka för en bredare syn på växthusanvändning. Studien visar att det finns stora spillvärmepotentialer bland särskilt högtempererade spillvärmekällor på västkusten och medeltempererade spillvärmekällor i Stockholmsområdet, eftersom dessa områden har både god spillvärmepotential och stor befolkning. Växthus kan byggas nära spillvärmekällan och kräver inte lika höga ingångstemperaturer som exempelvis fjärrvärmenäten, vilket gör spillvärme-växthus-system mer flexibla än spillvärme-fjärrvärme-system. Studien visar på viktiga fysiska, ekonomiska och organisatoriska förutsättningar för att bygga spillvärme-växthus-system, att det finns biologiska, sociala och kulturella potentialer med växthusen och vidare att det finns flera intressanta hållbarhetsaspekter med spillvärme-växthus-system, särskilt om de byggs rätt från början. Så gjordes i Habo, där studiens fallstudie gjordes. I Habo drivs ekologisk växthusodling med hjälp av spillvärme från en närliggande och elproducerande biogasanläggning, där de organiska resurserna består av gödsel och godisrester från en lokal godisindustri. Hela spillvärme-växthus-systemet är småskaligt och i stort sett kretsloppsanpassat. Modellen rekommenderas starkt både för projektet i Haninge och var helst man funderar på att bygga spillvärme-växthus-system, eftersom det överallt finns och alltid kommer att finnas tillgång på organiskt avfall. Energistudier visar att det finns stor potential i det organiska avfallet, särskilt från jordbruk
35
Ertem, Funda Cansu. "IMPROVING BIOGAS PRODUCTION BY ANAEROBIC DIGESTION OF DIFFERENT SUBSTRATES : Calculation of Potential Energy Outcomes." Thesis, Högskolan i Halmstad, Ekologi och miljövetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-15944.
Full textAbstract:
Global energy demand is rapidly increasing. In contrast, fossil fuel reserves are decreasing. Today, one of the major challenge is energy supply for the future. Furthermore, effects of global warming cannot be neglected anymore. Alternative energy sources such as biogas should be developed. The biomass has huge biogas potential. However, arable area in the world is limited. Therefore, substrate which will be used for biogas production should be chosen carefully. The objective of this study was to determine the biogas yields of different substrates. For this reason; red algae, green algae, mixture of brown and red algae, mixture of sugar beets and sugar beet leaves, mixture of straw and sugar beet leaves, mixture of maize and sugar beet leaves, straw, maize and ensiled ley were chosen to conduct a lab-based anaerobic digestion experiment. Biogas production and composition in mesophilic (37 OC) conditions during 25 days were measured and compared. The measurements were performed in a system consisting of 32, 1000 ml glass bottles with rubberstoppers. Potential energy production and energy requirements of each substrate were calculated. Methane yields ranged between 65.8 – 578.9 m3. t-1 VS (Volatile Solids). Whilst the highest methane yield was obtained from sugar beets, the lowest methane yields were obtained from the co-digestion of sugar beets and sugar beet leaves. The highest total energy potential for Sweden was obtained from ensiled ley and the lowest energy potential was obtained from maize. Sugar beet leaves were not good co-substrates, when they were digested with sugar beets, since they resulted in a decline in the methane yields. The highest total energy requirements for cropping and digestion were calculated for sugar beets. The lowest total energy requirements for cropping and digestion were calculated for ensiled ley. In the present study, digestion of sugar beets is suggested as good substrates for biogas production in Sweden, since it is more economical and helpful to solve the food&energy challenge. Although algae did not yield as much biogas as crops, they are interesting for biogas production since algae are considered a problem on the beaches and their high growth rates and abundance make them attractive for use in energy production. Due to lack of information, further studies are needed about economical aspects of algae for using in biogas plants.
36
Lindmark, Jesper, and Lundqvist Oscar. "Can organic waste provide sustainable fuel and energy in Rio de Janeiro? : An Early Assessment of waste-based biogas solutions in Rio de Janeiro, Brazil." Thesis, Linköpings universitet, Industriell miljöteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165774.
Full textAbstract:
Sustainable waste management remains a great challenge for many cities throughout the world. Landfilling is worldwide the most common way of treating municipal solid waste (MSW) and landfilling of organic matter releases the high potent gas methane, which contributes to global warming. If the biogas instead is collected, either from landfills or produced in a more optimal and controlled environment, it can be used as a fuel to substitute fossil fuels. In this thesis, these sorts of systems are referred to as biogas solutions. In Brazil, the eight largest economy in the world and by far the largest economy in Latin America, landfilling of MSW is essentially the only way MSW is disposed of. Rio de Janeiro, the second largest city of Brazil, have had long issues with waste management, with up until 2012 deposing waste to one of the largest open landfills in the world. This study was done in collaboration with Biogas Research Center (BRC): a national biogas competence center with interests in the Brazilian biogas sector as well as contacts with the Federal University of Rio de Janeiro. Furthermore, as Swedish organic waste management practices are globally in the front edge, the Swedish perspective of waste management combined with local knowledge, could be valuable to find more efficient means of managing residues. Before initiating an actual biogas project, it is reasonable to perform an early assessment. This thesis aimed to perform an early assessment of the biogas sector in Rio, which was carried out by utilizing a multi-criteria framework. The framework consists of four categories (potential, feasibility, economic- and environmental performance), 14 key areas and 59 sub-questions, which helped gather, structure and assess information. An eight-week field study in Rio de Janeiro was part of the study. The results show that no full separation of organic content is performed as source in Rio, which is why the study included the waste streams of mixed MSW (disposed in landfills) and partly sorted organic waste (approximately 85 % organic content; referred to as Waste with High Organic Content, WHOC). Sewage sludge from wastewater treatment plants was excluded from the study to enable a focus on MSW. Potential and feasibility are significantly higher for MSW compared to WHOC, although the authors argue WHOC (or even fully sorted organic waste) have substantial growth opportunities. The landfill receives approximately 1.2 million tonnes of organic wet waste per year and provides a biogas yield of 140 million Nm3 / year (50 – 55 % CH4); whereas 26 – 42 thousand tonnes of dry matter (DM) per year can be collected from WHOC, with a biogas yield potential of 6.6 – 19.5 million Nm3 / year (55 – 63 % CH4). The feasibility analysis showed that all key areas – competing applications, legislation and infrastructure – except economic instruments, are better rated for biogas production from MSW compared to WHOC. The most feasible area of use for the biogas in Rio de Janeiro was deemed to inject the gas in into the grid. The indicated environmental performance shows that injection of biogas to the gas grid reduces GHG emissions with 68 %; and for every tonne of DM digestate, approximately 8 kg phosphorous and 36 kg nitrogen can be replaced. The economic performance shows that biogas production from the landfill is more cost-efficient than from a bioreactor, however none of the biogas productions in Rio de Janeiro is profitable, which usually is expected of a waste management system. The study concludes with identifying several challenges the biogas sector in Rio will be facing: a lack of supply of biogas and no plan in action for increasing demand; economic challenges indicating need for investment support; and a lack of value chain for biofertilizers. The results of the study can hopefully provide stakeholders with a better understanding of opportunities and challenges with biogas solutions in Rio de Janeiro municipality, that ultimately can increase the chance for successful implementation in the region.Hållbar avfallshantering är fortsatt en stor utmaning för många städer runtom i världen. Deponering är globalt sett det vanligaste sättet att göra sig av med fast kommunalt avfall och deponering av organiskt avfall avger den potenta gasen metan, som bidrar till global uppvärmning. Om biogasen istället samlas upp, antingen från deponin eller produceras i en mer optimal miljö, kan gasen istället användas som bränsle för att substituera fossila bränslen. I denna rapport kallas denna typen av system för biogaslösningar. I Brasilien, världens åttonde största ekonomin och den avsevärt största ekonomin i Latinamerika, hanteras fast kommunalt avfall i princip endast genom deponering. Rio de Janeiro, Brasiliens nästa största stad, har länge haft problem med avfallshantering, som fram tills 2012 slängde allt sitt avfall i en av världens största öppna deponier. Denna studie genomfördes i samarbete med Biogas Research Center (BRC): ett nationellt kompetenscenter inom biogas med intresse av den Brasilianska biogassektorn, samt med kontakter till det federala universitetet i Rio. Eftersom Sverige ur ett globalt perspektiv ligger i framkant vad gäller hantering av organiskt avfall, kan den svenska synvinkeln av avfallshantering kombinerat med lokal kunskap vara värdefull för att hitta effektivare avfallshanteringssystem. Innan man genomför ett skarp biogasprojekt är det klokt att göra en förstudie. Denna uppsats syftar till att genomföra en förstudie av biogassektorn i Rio de Janeiro, som uträttades med hjälp av ett multi-kriterieramverk. Ramverket består av fyra kategorier (potential, genomförbarhet, samt ekonomisk- och miljömässig prestanda), 14 nyckelområden samt 59 underfrågor. Ramverket användes för att assistera i insamlandet, strukturerandet och utvärderandet av information. En fältstudie på åtta veckor i Rio de Janeiro var en del av studien. Resultatet visar att ingen fullständig separering av organiskt avfall sker i Rio, vilket är orsaken till att studien inkluderar avfallsströmmarna blandat kommunalt avfall (som deponeras; benämns MSW) och delvis sorterat organiskt avfall (innehåller 85 % organiskt innehåll; benämns WHOC). Avloppsslam exkluderades från studien för att fokusera på fast kommunalt avfall. Potentialen och genomförbarheten är markant högre för MSW jämfört med WHOC, dock skall det understrykas att tillväxtpotentialen för WHOC är stor vilket ej framgår av siffrorna. Deponin mottager årligen nära 1.2 miljoner ton organiskt avfall (inkl. vatten) som ger en biogasutdelning på 140 miljoner Nm3 / år (50 – 55 % CH4); medan WHOC har en potential på 26 – 42 tusen ton (torrvikt) per år med en biogasutdelning på 6.6 – 19.5 miljoner Nm3 / år (55 – 63 % CH4). Genomförbarhetsanalysen för avfallsströmmarna visade att alla nyckelområden förutom ekonomiska instrument var värderade högre för MSW jämfört med WHOC. Studien visar vidare att det mest genomförbara användningsområdet för biogasen är injektion till gasnätet. Miljömässiga prestandan visar att substituering av naturgas med biogas kan sänka växthusgasutsläpp med 68 %, och för varje ton (torrvikt) av rötrester kan ca 8 kg fosfor och 36 kg kväve ersättas. Ekonomiska prestandan visar att biogasproduktion från deponi är mer kosteffektivt än i en bioreaktor, samt att ingen av biogaslösningarna är lönsamma, vilket kan väntas av en avfallshanteringslösning. Studien avslutas med att identifiera en rad utmaningar som biogassektorn i Rio ställs inför: en avsaknad på tillgång av biogas och ingen aktiv plan för att öka produktionen; ekonomiska utmaningar som indikerar ett behov av investeringsstöd; en brist på värdekedja för biogödsel. Resultatet av studien kan förhoppningsvis ge intressenter en bättre förståelse för vilka möjligheter och utmaningar som biogaslösningar ställs inför i Rio de Janeiro kommun – som i förlängningen kan öka möjligheterna för framgångsrika implementeringar av biogasprojekt i regionen.
37
Poudel, Bishnu Chandra. "Carbon Balance Implications Of Forest Biomass Production Potential." Doctoral thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-22075.
Full textAbstract:
Forests in boreal and temperate forest-ecosystems have an important function since they sequester atmospheric carbon by uptake of carbon-dioxide in photosynthesis, and transfer and store carbon in the forest ecosystem. Forest material can be used for bio-fuel purposes and substitute fossil fuels, and supply wood products, which can replace carbon- and energy-intensive materials. Therefore it is vital to consider the role of forests regarding today´s aim to mitigate climate change. This thesis assess (i) how climate change affects future forest carbon balance, (ii) the importance of different strategies for forest management systems, and biomass production for the carbon balance, (iii) how the use of forest production affect the total carbon balance in a lifecycle perspective, and (iv) how the Swedish carbon balance is affected from the standpoint of both the actual use of forest raw material within Sweden and what Swedish forestry exports. The analysis was made mainly in a long-term perspective (60-300 year) to illustrate the importance of temporal and also the spatial perspective, as the analysis includes stand level, landscape level, and national level. In this thesis, forestry was considered a system. All activities, from forest regeneration to end use of forest products, were entities of this system. In the evaluation, made from a systems perspective, we used life-cycle analysis to estimate carbon stock in different system flows. Different forest management systems and forest production were integrated in the analyses. Different forest management scenarios were designed for the Swedish forest management in combination with the effect of future climate change; (i) intensive forest practice aiming at increased growth, (ii) increased forest set-aside areas, changes in forest management systems for biomass production, and (iii) how the use of forest production affect the total carbon balance (construction material, bioenergy and other domestic use). The results showed that future climate changes and intensive forest management with increased production could increase the biomass production and the potential use of forest raw material. This has a positive effect on carbon storage for the forest carbon stock, litter production and carbon storage in the ground etc. and help mitigating carbon-dioxide. Increased forest set-aside areas can increase the short-term carbon stock in forest ecosystems, but will reduce the total long-term carbon balance. The net carbon balance for clear-cut forestry did not differ significantly from continuous-cover forestry, but was rather a question of level of growth. Most important, in the long term, was according to our analysis, how forest raw material is used. Present Swedish forestry and use of forest raw material, both within Sweden and abroad, reduce carbon-dioxide emissions and mitigate climate change. The positive effect for the total carbon balance and climate benefit take place mostly abroad, due to the Swedish high level of export of wood products and the higher substitution effects achieved outside Swedish borders. One strategy is to increase production, harvest and change the use of Swedish forest raw material to replace more carbon intensive material, which can contribute to significant emission reduction. Carbon-dioxide mitigation, as a result of present Swedish forestry, was shown to be almost of the same level as the total yearly emission of greenhouse gases. The total carbon benefit would increase if the biomass production and felling increased and if Swedish wood products replaced carbon intensive materials.This thesis shows also that, by changing forest management, increase the growth and the use of forest raw material and export of forest material we can contribute to even larger climate benefits. In a long-term perspective, the substitution effects and replacement of carbon- and energy-intensive materials are of greater significance than carbon storage effects in forests. A more production oriented forestry needs to make balances and increase the prerequisite for biological diversity, improve recreation possibilities, and protect sensitive land areas and watersheds.Climate benefits, from Swedish forestry, are highly dependent on policy decision-making and how that can steer the direction for the Swedish forestry.
38
Groode, Tiffany Amber 1979. "Biomass to ethanol : potential production and environmental impacts." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43144.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references.
This study models and assesses the current and future fossil fuel consumption and greenhouse gas impacts of ethanol produced from three feedstocks; corn grain, corn stover, and switchgrass. A life-cycle assessment approach with an integrated Monte Carlo uncertainty analysis is applied to each of these three bioethanol pathways. Incorporating a Monte Carlo uncertainty analysis within a life-cycle model enables one to account for system variability within the agricultural, technological, and geographic arenas. This results in a range of energy and greenhouse gas impacts rather than previous single-valued estimates. This uncertainty analysis brings greater clarity to the ethanol debate through evaluating the probability of previously published life-cycle assessment net energy results, from reports such as Farrell, Wang, Shapouri, and Pimentel. Lifecycle assessment net energy results show corn grain ethanol to have a positive value when DDGS coproducts are included within the assessment boundary and a slightly negative value when they are not. The system net energy value and GHG emissions are also sensitive to system input assumptions and geographic location. For lignocellulosic ethanol produced from corn stover and switchgrass, a positive net energy value and reduced GHG emissions are seen when compared to gasoline. In addition to net energy results and system GHG emissions, the petroleum displacement and land use impacts for an expanding and evolving ethanol industry are also evaluated.Corn grain, corn stover, and switchgrass-based ethanol potential production levels are also analyzed. It was determined that 55-65 billion liters per year of corn grain ethanol could potentially be produced in the next 10 years, consuming 30% of future US corn grain production. Corn stover and switchgrass have the potential to produce 25-35 and 10-20 billion liters per year of ethanol, respectively.
(cont) These ethanol production results were then applied to assess the feasibility and environmental impact of achieving the new Renewable Fuels Standard, of producing 136 billion liters of renewable fuels by 2022. This study concluded that while the scale is potentially feasible from these three feedstocks, the timeline to achieve this scale would be very challenging given the cellulosic ethanol technological and economic advances that are still needed.
by Tiffany A. Groode.
Ph.D.
39
Brereton, Nicholas James Beresford. "SRC willow development, biomass composition and biofuel potential." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6920.
Full textAbstract:
The aims of this PhD were to examine nitrogen allocation and partitioning in Short Rotation Coppice (SRC) willow in regard to tree development and to investigate biomass composition and cell wall structure for the purpose of assessing and understanding biofuel potential. To address these topics four major experiments were performed and are presented in the thesis. An investigation of SRC willow development and nitrogen dynamics was conducted as a pot trial comprising 14 different genotypes from a willow mapping population. The genotypes were selected on the extremity and consistency of their field biomass yields. Fertiliser enriched with the stable isotope nitrogen 15 was applied as a means of nitrogen surveillance. One of the findings was that higher biomass yielding varieties of SRC willow had increased nitrogen-use-efficiency yet less (or later) nitrogen remobilisation in the autumn. The recalcitrance of the cell wall to enzymatic saccharification was assessed across 138 field-grown genotypes of the same willow mapping population. The aim was to identify any relationships between glucose yield and several biomass yield traits and to identify any quantitative trait loci (QTL) associated with enzymatic saccharification. Four QTL associated to enzymatic saccharification were identified and no relationship was found between glucose and biomass yield traits. A third experiment aimed to modify cell wall composition and structure of a single cultivar of willow grown in a pot trial. Tension wood, fibre cells containing an extra cell wall layer unique to angiosperms, and cellulose synthesis inhibited phenotypes were both induced. These modifications were accomplished through chemical and environmental treatments during development and their impact on composition and cell wall recalcitrance was assessed. Tension wood formation was found to increase glucose yields. The final main experiment used 35 of the UK’s leading biomass yielding willow varieties, grown in the field, to assess not only the variation in composition and enzymatic saccharification but also to identify any relationships between these two traits and a variety of morphological traits. The final part of the experiment investigated how variation in these traits interacted with dilute acid pretreatment. Surprisingly lignin content did not significantly correlate with cell wall recalcitrance to enzymatic saccharification. Another important finding was that enzymatic saccharification without the pretreatment correlated with enzymatic saccharification after the pretreatment. General introduction and general materials and methods chapters are included. A final summary discussion chapter is also included in order to address the overall impact of these findings on biofuel potential.
40
Huggett, David Alan John. "Potential insect pests of the biomass crop Miscanthus." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/7180.
Full text
41
Caille, L'Etienne Thibault. "Potential for Biogas Production from Residues of a Slaughter House at High Altitude in Bolivia." Thesis, KTH, Energi och klimatstudier, ECS, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-62238.
Full textAbstract:
The potential for biogas production with residues of a slaughter house in the climatic conditions of LaPaz has been determined during the master’s thesis. The project was carried out at a pilot plantconsisting of three tubular biodigesters made of polyethylene. The study showed that there is strong potential for biogas and biofertilizer production from residues ofslaughter houses at high altitude and cold climate in Bolivia, even by using blood which is the majorcomponent responsible of the water contamination. This production led to avoid water contamination,to limit the greenhouse effect by limiting the methane release into the atmosphere due to uncontrolledwaste management, and to improve the agriculture yields through the use of organic fertilizer. After afirst period of investigation, new parameters of operation of the pilot plant were defined in order tooptimize the biogas and biofertilizer production. But the tubular biodigesters made of polyethylenecould difficultly be further developed at industrial scale. Thus the final part of the project consisted in the design of a new type of low-cost pilot plant whichcould solve the environmental burden caused by slaughter houses residues in all Bolivia, whilegenerating more economical benefits from the biogas and biofertilizer production. This pilot plant wasintended to be further scaled-up and developed in all Bolivia if the new investigation carried out afterthe master’s thesis would give satisfactory results. The estimations of industrial plants based on theresults of the pilot plant of Achachicala showed that the slaughter houses could work only by usingbiogas resulting from the anaerobic digestion of their residues, while generating important amounts ofbiofertilizer which would be a source of important economical benefits.
42
Naik, Linus. "An investigation of the potential and the limitations of small-scale biogas in urban Africa." Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/30788.
Full textAbstract:
Continuing urbanisation in Sub-Saharan Africa provides many development challenges including; energy provision, waste management and sanitation. On-site biogas has the potential to provide renewable energy to meet primary energy needs, whilst also addressing waste management and possibly sanitation. In urban settings, up to 50% of the municipal waste in urban can comprise organic waste which typically remains an untapped energy source, while the total waste volume continually increases with population growth. Whilst some countries (including Ethiopia and Uganda) have support via national government and/or foreign investment for biogas deployment, their focus is on rural biogas for agricultural waste, not urban biogas for municipal waste. This thesis investigates the case for small-scale biogas as a technology to assist sustainable urban development through understanding factors which will ensure operational success to safeguard investment. The factors investigated were productivity, stability and the need for remote monitoring. The research was divided into three distinct phases which occurred chronologically. The first phase was observational and developmental, in which one biogas unit in a semi-controlled environment was monitored. Some initial insight into the factors which caused instability (in this case, the addition of simple carbohydrates) as well as two methods of mitigation of instability (namely addition of lime and a cessation of feed) were noted for future investigation. Also, in this phase, a mobile phone application, called the “Biogas Monitoring Tool” was developed and refined, accompanied by a monitoring methodology to collect information on measured variables which were considered to inform productivity and stability of small-scale biogas units. Of the variables mentioned, the laboratory method of evaluation of two in particular (pH and temperature) was replaced with more practical and rudimental measuring techniques. The appropriateness of the replacements was statistically analysed, evaluated and found to be acceptable for the intended purposes. The second phase of research involved the widespread rollout of the Biogas Monitoring Tool developed in the first phase. The platform was used to gather data from ten small-scale biogas units across southern Africa to further investigate and analyse the factors which affected the productivity and stability of smallscale biogas units. Readings of pH, burn time, pressure, mass and type of feed were captured through the Biogas Monitoring Tool over twelve months. The analysis showed episodes of instability of biogas units linked to changing feeding regimes of simple carbohydrates, organic loading rates as well as changes in feed ratios/frequency. In terms of productivity of the biogas units, seasonal fluctuations in the five units which were monitored over the winter months was evident, as well as potential underutilization of biogas produced. Furthermore, it was noted that there was better utilisation of gas for institutional installations compared to domestic installations. It was also shown that in five of the biogas units, the stability of the unit had an influence on the quality of gas produced, and it was indicative that it had an influence on the quantity of gas produced. For the third and final phase of research, theories developed from insight gleaned in second phase were tested on one biogas unit in a controlled environment. There were three sets of experiments conducted on this unit which had a pre-determined feeding regime. Also, the biogas stove was burned daily until the biogas ran out, to quantify the productivity of the biogas unit. Firstly, a stepwise addition of the organic fraction of municipal solid waste was introduced into the feeding regime. In this case, it was demonstrated that the organic fraction of municipal solid waste can in fact be the sole feed-stock for biogas unit, with the proviso that there was appropriate knowledge support which includes quick mitigation strategies for periods of instability. Secondly, the effect of pre-treatment of the organic fraction of municipal solid waste was investigated. It was found here that the pre-treatment did appear to improve the stability of the biogas unit, a consideration which may be significant for potential widespread adoption of the technology. Finally, the effect of temperature on gas production was confirmed and quantified, with higher average temperatures showing higher gas production. In conclusion, it was found that all the small-scale units which formed part of this research showed episodes of instability. When considering this technology for energy provision for urban development, there are important considerations around feedstock variability by way of feed type, volume, and frequency affect the stability of these unit. With reference to productivity, it was shown, not only that temperature naturally does affect gas production, but also that the productivity is linked to the stability. Furthermore, it was deemed that the type of setting (institutional versus domestic) was in fact more significant than the ambient temperature or the feeding regime when considering gas use and gas utilisation as indicators of productivity. Finally, with regard to knowledge support via remote monitoring, it was shown that simple and practical measurements were able to provide insight into factors which affected productivity and stability of small-scale biogas units. The final phase further utilised the remote monitoring tool to actively manage the operation of the biogas unit and quickly mitigate instability. Thus, small-scale biogas has the potential to be adopted as technology for energy provision in urban development. The limitations of the application are that waste-based biogas would meet only an portion of the total energy requirement in any particular urban area and that based on the findings of this research, all units are subject to periods of instability. There are various mitigation strategies for instability, some of which involve active management, which may be supplied remotely.
43
Vanyaza, Sidwell Luvo. "Assessment of the potential contribution of biogas to mitigation of climate change in south africa." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9074.
Full textAbstract:
Includes bibliographical references.South Africa has its fair share in the global greenhouse gas (GHG) emissions, with recorded 2010 emissions per capita of 10tons/year. This is caused by the energy supply of the country which relies heavily on fossil fuels to drive its energy intensive economy. If this continues under “business as usual”, consequences like water and food shortage may be exacerbated. The waste sector has a share of 3 in national GHG emissions. These are caused by methane from biogas produced through anaerobic digestion of organic waste. The objective of this study was to assess the potential contribution that can be achieved in reducing the national GHG emissions by converting waste emissions into useful energy or capturing and destroying them. Three waste resources were investigated because of their abundance in the country: municipal solid waste, municipal wastewater and livestock manure. The national picture of municipal waste was extrapolated from the waste data available in 7 metros in the country (City of Cape Town, Johannesburg, Tshwane, Ekurhuleni, EThekwini, Nelson Mandela Bay, and Buffalo City municipalities). Projected GDP and population growths were used as indicators for extrapolating the national data. The total national organic waste derived from these waste categories was used to estimate their emission share in national GHG emissions and biogas generation in terms of methane production from each waste type. This was forecasted from 2010 to 2025. The methane gas production was optimised by assuming different waste combinations like: municipal solid waste and wastewater, wastewater and livestock manure, and remaining wastewater. In addition, the possible amount of electricity or heat produced from this biogas was estimated. This useful energy was used to evaluate the emission reduction potential (ERP) in the national GHG emissions of the country under “growth without constraints”. All these computations were performed by using MS Excel software. It was found that the total organic waste predicted during this period varied from 12 to 17Mton, with the waste emissions share being about 2 of the national GHG emission. Methane generated from this waste was about 644-1075Mm3 while the total optimal methane generated from these waste combinations was estimated to be 1770- 2650Mm3. In addition, 673-1123GWh of electricity and 1255-2150GWh of heat could be produced (without optimization) from methane over the same period of the forecast. For optimal methane production, the possible useful energy was estimated to be 1362-2037GWh of electricity and 2894- 4362GWh of heat. The ERP of methane capture and conversion to useful energy was about 2.1- 2.5. It is concluded that a) capturing and utilisation of methane gas from waste contributes to the reduction of the GHG emissions, b) optimisation of biogas production from waste increase methane yield and therefore useful energy, and c) the best contribution of biogas in climate change mitigation in South Africa would come from the optimal production of methane from waste.
44
Thrän, Daniela, Katja Bunzel, Ulrike Seyfert, Vanessa Zeller, Marcel Buchhorn, Klaus Müller, Bettina Matzdorf, et al. "Final Report Global and Regional Spatial Distribution of Biomass Potentials." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-137748.
Full textAbstract:
The German Government’s Integrated Energy and Climate Programme (IEKP) and the National Biomass Action Plan set ambitious targets for the further development of bioenergy until 2020. The share of energy from biomass is supposed to reach 8 % and 9.7 % of the total power consumption and of the total heat usage, respectively. The share of biofuels on the total consumption of fuels for transportation should rise up to 12 % (energetic) by 2020. This project aims to assess the possibilities of achieving the IEKP targets for bioenergy in a regional and global context. On a regional as well as global level, the potentials of different biomasses were determined in different development scenarios until 2020. Furthermore, the extent to which remote sensing could contribute in improving the spatial specification of biomass resources and whether it could be used as a monitoring system for the early detection of land use changes was investigated. On the regional level, the spatial implications of energetic biomass use was analysed with regard to environmental impacts and land use conflicts. Depending on their significance of spatial impacts, instruments of spatial planning were assessed in order to steer the supply of bioenergy. [... from Executive Summary]
45
Thrän, Daniela, Katja Bunzel, Ulrike Seyfert, Vanessa Zeller, Marcel Buchhorn, Klaus Müller, Bettina Matzdorf, et al. "Final Report Global and Regional Spatial Distribution of Biomass Potentials." DBFZ Deutsches Biomasseforschungszentrum, 2011. https://slub.qucosa.de/id/qucosa%3A4324.
Full textAbstract:
The German Government’s Integrated Energy and Climate Programme (IEKP) and the National Biomass Action Plan set ambitious targets for the further development of bioenergy until 2020. The share of energy from biomass is supposed to reach 8 % and 9.7 % of the total power consumption and of the total heat usage, respectively. The share of biofuels on the total consumption of fuels for transportation should rise up to 12 % (energetic) by 2020. This project aims to assess the possibilities of achieving the IEKP targets for bioenergy in a regional and global context. On a regional as well as global level, the potentials of different biomasses were determined in different development scenarios until 2020. Furthermore, the extent to which remote sensing could contribute in improving the spatial specification of biomass resources and whether it could be used as a monitoring system for the early detection of land use changes was investigated. On the regional level, the spatial implications of energetic biomass use was analysed with regard to environmental impacts and land use conflicts. Depending on their significance of spatial impacts, instruments of spatial planning were assessed in order to steer the supply of bioenergy. [... from Executive Summary]
46
Hagström, Peter. "Biomass Potential for Heat, Electricity and Vehicle Fuel in Sweden." Doctoral thesis, Uppsala, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-85623.
Full textAbstract:
The main objective of this thesis was to determine how far a biomass quantity, equal to the potential produced within the Swedish borders, could cover the present energy needs inSwedenwith respect to economic and ecological circumstances. Three scenarios were studied where the available biomass was converted to heat, electricity and vehicle fuel. Three different amounts of biomass supply were studied for each scenario: 1) potential biomass amounts derived from forestry, non-forest land, forest industry and community; 2) the same amounts as in Case 1, plus the potential biomass amounts derived from agriculture; 3) the same amounts as in Case 1, plus 50% of the potential pulpwood quantity. For evaluating the economic and ecological circumstances of using biomass in the Swedish energy system, the scenarios were complemented with energy, cost and emergy analysis. The scenarios indicated that it may be possible to produce 170.2 PJ (47.3 TWh) per year of electricity from the biomass amounts in Case 2. From the same amount of biomass, the maximum annual production of hydrogen was 241.5 PJ (67.1 TWh) per year or 197.2 PJ (54.8 TWh) per year of methanol. The energy analysis showed that the ratio of energy output to energy input for large-scale applications ranged from 1.9 at electric power generation by gasification of straw to 40 at district heating generation by combustion of recovered wood. The cost of electricity at gasification ranged from 7.95 to 22.58 €/GJ. The cost of vehicle work generated by using hydrogen produced from forestry biomass in novel fuel cells was economically competitive compared to today’s propulsion systems. However, the cost of vehicle work generated by using methanol produced from forestry biomass in combustion engines was rather higher compared to use of petrol in petrol engines. The emergy analysis indicated that the only biomass assortment studied with a larger emergy flow from the local environment, in relation to the emergy flow invested from society after conversion, was fuel wood from non-forest land. However, even use of this biomass assortment for production of heat, electricity or vehicle fuels had smaller yields of emergy output in relation to emergy invested from society compared to alternative conversion processes; thus, the net contribution of emergy generated to the economy was smaller compared to these alternative conversion processes.QC 20120217
47
Gilson, Eoin. "Biogas production potential and cost-benefit analysis of harvesting wetland plants (Phragmites australis and Glyceria maxima)." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-34424.
Full textAbstract:
Biogas production from energy crops grown on arable land often competes with food and feed production. Wetland plants offer an alternative source of biomass as well as offering a number of environmental benefits such as nutrient removal from wastewaters, carbon sequestration and reducing the use of mineral fertilizer. The aim of this study is to investigate the effect of harvest time on biogas production of Phragmites australis and Glyceria maxima and to perform a cost-benefit analysis of using these wetland plants as a substrate for biogas production. The results of the batch experiment show that the overall biogas production and specific methane yields of biomass harvested in June was higher than biomass harvested in September due the increased lignocellulosic nature of the more mature September plant. The cost-benefit showed that in Sweden it is not currently profitable to solely use wetland plants for biogas production. For both species the highest costs were seen in the June harvested biomass, this was due to the much higher fresh weight and increased transportation costs. For both species the highest revenues generated were the June harvested biomass, this was due to the higher specific methane yields. It was found that the harvest time that was closest to profitability from both species was the June harvest for Phragmites australis. Although the costs were higher for harvesting in June, this was outweighed by the higher amount of electricity produced for this scenario. If transportation distance was to be increased it could result in September being the favourable harvest time. Therefore, individual circumstances of the farmers could decide which is the optimal harvest time. Although solely using wetland plants for biogas production is not currently profitable, co-digestion and pre-treatment are options to investigate that could change this. Also if a greater financial value is put on the socioeconomic benefits such as increased biodiversity, aesthetic value and global warming mitigation it may be financially viable in the future.
48
Wu, Dan Hua. "The effect of water potential on soil microbial biomass." Thesis, University of Aberdeen, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290290.
Full textAbstract:
This study investigated the effect of water potential on soil microbial C and N pools. Two soil types were treated with additions of salt solution to establish osmotic water potentials, and by ceramic plate - pressure chamber apparatus to establish matric water potentials. Soils were then subjected to short-term incubations. Soil microbial C and N contents (BC and BN) were measured mainly by the fumigation-extraction and fumigation-incubation methods. Results showed that both Microbial C and N pools were markedly affected by soil water potential. The soil microbial C content always showed an increase with increasing water stress and then a decrease beyond a threshold value of water stress, compared to the microbial C content at a control water potential of -0.03 MPa (-0.3 Bar). This response pattern to water stress was true, not only for osmotic stress, but also for matric stress, and regardless of the osmotic agent employed. The response pattern of the microbial N pool to water stress generally contrasted with that of the C pool, and depended on the osmotic strength of the extraction solution (K2SO4) used in the determination. Non-isotonic extraction after fumigation resulted in a decrease in microbial N content with increasing water stress, while isotonic extraction resulted in an increase with increasing water stress, beyond a threshold value of water stress. Soil microbial C/N ratio always increased with increasing water stress. Matric water stress had a more marked effect on BC and BN than osmotic stress. The possible reasons for the response patterns of BC, BN and microbial C/N ratio have been discussed in this thesis. Some suggestions on the methodology of microbial biomass measurement for water stressed soil samples have been made, and mainly relate to the biomass fumigation techniques and possible changes in the Kc, Kce and Kn values under water stress, and to the substrate induced respiration (SIR) method and suppressed respiration under water stress.
49
Poudel, Bishnu Chandra. "Forest biomass production potential and its implications for carbon balance." Licentiate thesis, Mittuniversitetet, Institutionen för teknik och hållbar utveckling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-17281.
Full textAbstract:
An integrated methodological approach is used to analyse the forest biomass production potential in the Middle Norrland region of Sweden, and its use to reduce carbon emissions. Forest biomass production, forest management, biomass harvest, and forest product use are analyzed in a system perspective considering the entire resource flow chains. The system-wide carbon flows as well as avoided carbon emissions are quantified for the activities of forest biomass production, harvest, use and substitution of non-biomass materials and fossil fuels. Five different forest management scenarios and two biomass use alternatives are developed and used in the analysis. The analysis is divided into four main parts. In the first part, plant biomass production is estimated using principles of plant-physiological processes and soil-water dynamics. Biomass production is compared under different forest management scenarios, some of which include the expected effects of climate change based on IPCC B2 scenario. In the second part, forest harvest potentials are estimated based on plant biomass production data and Swedish national forest inventory data for different forest management alternatives. In the third part, soil carbon stock changes are estimated for different litter input levels from standing biomass and forest residues left in the forest during the harvest operations. The fourth and final part is the estimation of carbon emissions reduction due to the substitution of fossil fuels and carbon-intensive materials by the use of forest biomass. Forest operational activities such as regeneration, pre-commercial thinning, commercial thinning, fertilisation, and harvesting are included in the analysis. The total carbon balance is calculated by summing up the carbon stock changes in the standing biomass, carbon stock changes in the forest soil, forest product carbon stock changes, and the substitution effects. Fossil carbon emissions from forest operational activities are calculated and deducted to calculate the net total carbon balance.The results show that the climate change effect most likely will increase forest biomass production over the next 100 years compared to a situation with unchanged climate. As an effect of increased biomass production, there is a possibility to increase the harvest of usable biomass. The annual forest biomass production and harvest can be further increased by the application of more intensive forestry practices compared to practices currently in use. Deciduous trees are likely to increase their biomass production because of climate change effects whereas spruce biomass is likely to increase because of implementation of intensive forestry practices.IIIntensive forestry practices such as application of pre-commercial thinning, balanced fertilisation, and introduction of fast growing species to replace slow growing pine stands can increase the standing biomass carbon stock. Soil carbon stock increase is higher when only stem-wood biomass is used, compared to whole-tree biomass use. The increase of carbon stocks in wood products depends largely on the magnitude of harvest and the use of the harvested biomass. The biomass substitution benefits are the largest contributor to the total carbon balance, particularly for the intensive forest management scenario when whole-tree biomass is used and substitutes coal fuel and non-wood construction materials. The results show that the climate change effect could provide up to 104 Tg carbon emissions reduction, and intensive forestry practices may further provide up to 132 Tg carbon emissions reduction during the next 100 years in the area studied.This study shows that production forestry can be managed to balance biomass growth and harvest in the long run, so that the forest will maintain its capacity to increase standing biomass carbon and provide continuous harvests. Increasing standing biomass in Swedish managed forest may not be the most effective strategy to mitigate climate change. Storing wood products in building materials delays the carbon emissions into the atmosphere, and the wood material in the buildings can be used as biofuel at the end of a building life-cycle to substitute fossil fuels.These findings show that the forest biomass production potential in the studied area increases with climate change and with the application of intensive forestry practices. Intensive forestry practice has the potential for continuous increased biomass production which, if used to substitute fossil fuels and materials, could contribute significantly to net carbon emissions reductions and help mitigate climate change.
50
Chiang, Nicholas (Nicholas Kuang Hua). "Quantifying the economic potential of a biomass to olefin technology." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33628.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, September 2005.Includes bibliographical references (leaves 39-40).
Oil is one of the most valuable natural resources in the world. Any technology that could possibly be used to conserve oil is worth studying. Biomass waste to olefin (WTO) technology replaces the use of oil as a feedstock. WTO technology is actually a combination of two different processes: the waste to methanol (WTM) process and the methanol to olefins (MTO) process. However, WTO technology is still not commercially applied. Despite the environmentally beneficial advantages of biomass waste to olefins technology, the economic advantages or disadvantages still need to be explored further. This thesis tries to determine under what operating conditions (production volumes, feedstock prices, etc.) make the biomass waste to olefins technology most competitive. The WTM process is the economical limiting factor in the WTO technology. However, for relatively significant production volumes, the WTO technology is still competitive with a slight decrease in biomass feedstock price.
by Nicholas Chiang.
M.Eng.