Dissertations / Theses on the topic 'Waste-to-energy plant'

The thesis outlined in this report has been done as a sub-project in cooperation between the municipalities Borlänge in Sweden and Chisinau in Moldova. The project aimed to explore the region's economic and environmental opportunities for waste incineration with energy recovery, also known as Waste to Energy. At present, the solution to the waste situation is unmonitored landfills with smaller sorting operations. Environmentally, this is a poor solution and although there are plans for change, no specific strategy has been presented. Another important issue is Moldova's dependence on foreign produced energy. The country's energy system is dependent on imported natural gas, and only a small part of the country's electrical energy is produced domestically. What makes the waste to energy so interesting for this region is that it contributes to an improvement in both of these issues by using the waste as fuel to reduce energy dependency. The study has been done without specific waste composition data for the Chisinau region. With this in mind a dynamic model in several steps has been made, designed to obtain new results depending on what waste composition is specified. The results of this study show that implementation of a waste incineration plant in the Chisinau energy system is economically and environmentally feasible, given the current conditions. The proposed plant is designed to annually handle 400,000 tonnes of waste, and would with the assumed waste composition deliver 560 GWh of district heat and 260 GWh of electric energy. This production provides an annual profit of 31.6 M €, which gives a positive net present value after the project amortization. Compared with the city's current solution with landfills and gas turbines, the project also provides a significant environmental improvement. During the plant's design lifetime, greenhouse gas emissions are 53.9%, and only 6.8% with the assumption that only a portion of the carbon content of the waste is of fossil origin.

The ISO 50001 standard on energy management systems was released in 2011 with the aim of providing organizations with a standardised guideline for the evaluation and continual improvement of energy performance. Complex structures such as the waste to energy (WTE) sector, which must comply with social, environmental, economic and productivity objectives, can benefit from the development of a compliant energy management system (EnMS). Energy efficiency and energy savings contribute to the mitigation of the heavy cost of such a facility, while the benchmark analysis allows verifying the state of the system and the potential areas for improvement. The energy performance improvements can be valorised on an environmental base, and proper promotion of the process can contribute to the mitigation of social opposition. This thesis reviews the energy performance of a waste to energy facility located in Lecco, Italy, using the information available from the control system already installed in the company. Regression analysis is used to fit linear and polynomial functional forms to the energy consumption data and create the energy baseline for the areas of significant energy use and production with a predictive power of 59 – 92%. The difference among the baseline and the actual energy consumption is proposed as energy performance indicator, in order to appreciate the results of the improvement opportunities, and a set of key performance indicators are evaluated for internal and external benchmarking of the facility. The economic feasibility of a selection of sectorial Best Available Technologies (BATs) and the related energy performance improvement is evaluated, revealing that 2 – 16 M€ can be invested in the system retrofit; the creation of synergies with the facility heating, cooling and electricity demand is also suggested. Lastly, an energy, economic and environmental analysis is suggested as a ranking system for the identified improvement opportunities. The methodology and results of this study are intended to provide a proper energy review for Silea Spa, suggest a review procedure for other WTE facilities willing to develop a compliant EnMS and enrich the literature with a case study on WTE. For the Italian context, which is currently facing difficulties in the modernization of the waste management system (WMS), the ISO 50001 application on WTE facilities offers a unified structure that can be used by the government to map the current status of each facility and develop the legislative framework in accordance to the needs of the WMS, the circular economy and the public opinion.
ISO 50001-standarden för energihanteringssystem släpptes 2011 för att ge organisationer en standardiserad riktlinje för utvärdering och kontinuerlig förbättring av energiprestanda. Komplexa strukturer som sektorn för avfall till energi (WTE), som måste uppfylla målen socialt, miljömässigt, ekonomiskt och produktivt, kan dra nytta av utvecklingen av ett kompatibelt energihanteringssystem (EnMS). Energieffektivitet och energibesparingar bidrar till att mildra den stora kostnaden för en sådan anläggning, medan jämförelseanalysen gör det möjligt att verifiera systemets tillstånd och de potentiella förbättringsområdena. Förbättringen av energiprestanda kan värderas på en miljöbas, och en korrekt främjande av processen kan bidra till att mildra social opposition. Denna avhandling granskar energiprestanda för ett slöseri till en energianläggning i Lecco, Italien, med hjälp av den information som finns tillgänglig från det styrsystem som redan är installerat i företaget. Regressionsanalys används för att passa linjära och polynomiska funktionsformer till energiförbrukningsdata och skapa energigrundnivå för områdena med betydande energianvändning och produktion med en prediktiv effekt på 59-92%. Skillnaden mellan baslinjen och den faktiska energiförbrukningen föreslås som indikator för energiprestanda för att uppskatta resultaten av förbättringsmöjligheterna och en uppsättning nyckelresultatindikatorer utvärderas för intern och extern riktmärkning av anläggningen. Den ekonomiska möjligheten för ett urval av sektorns bästa tillgängliga teknik (BAT) och den därmed sammanhängande förbättringen av energieffektiviteten utvärderas, vilket visar att 2 - 16 miljoner euro kan investeras i systemets eftermontering. skapandet av synergier med anläggningens uppvärmning, kylning och el efterfrågan föreslås också. Slutligen föreslås en energi-, ekonomisk och miljöanalys som ett rankningssystem för de identifierade förbättringsmöjligheterna. Metoden och resultaten av denna studie är avsedda att ge en ordentlig energianalyse för Silea Spa, föreslå ett granskningsförfarande för andra WTE-anläggningar som är villiga att utveckla en kompatibel ENMS och berika litteraturen med en fallstudie om WTE. För det italienska sammanhanget, som för närvarande står inför svårigheter i moderniseringen av avfallshanteringssystemet (WMS), erbjuder ISO 50001-tillämpningen på WTE-anläggningar en enhetlig struktur som kan användas av regeringen för att kartlägga nuvarande status för varje anläggning och utveckla den rättsliga ramen i enlighet med WMS, den cirkulära ekonomins och den allmänna opinionens behov.

In this dissertation the waste incineration process has been described, an overview of the state of the art control methodologies given and a new approach, based on input/output linearization and extremum seeking has been presented. This approach has been tested on a model appositely designed. The results have shown that it is possible to control the waste bed temperature to certain reference values, with robustness against changes in the waste composition. It is furthermore possible to identify reference values for the waste bed temperature such as the steam ow rate is maximized, while at the same time fulfilling operational constraints.

Among all the flue gas components produced in waste-to-energy plants, acid airborne pollutants such as SO2 and HCl have the most rigorous emission standards provided by the European Parliament. Their removal is thus a key step of the flue gas treatment which is mainly achieved with the Dry Treatment Systems (DTS), technologies based on the direct injection of dry solid sorbents which is capable to subtract the acid from the gas stream with several important advantages and high removal efficiencies. However, the substantial lack of a deeper industrial knowledge makes difficult to determine accurately an optimal operating zone which should be required for the design and operation of these systems. The aim of this study has been therefore the exploration, while basing on an essential engineering expertise, of some of the possible solutions which the application of multivariate statistical methods on process data obtained from real plants can give in order to identify all those phenomena which rule dry treatment systems. In particular, a key task of this work has been the seeking for a general procedure which can be possibly applied for the characterization of any type of DTS system, regardless of the specific duty range or design configuration. This required to overcome the simple mechanical application of the available techniques and made necessary to tailor and even redefine some of the available standard procedures in order to guarantee specific and objective results for the studied case. Specifically, in this so called chemometric analysis, after a pre-treatment and quality assessment, the process data obtained from a real working plant was analyzed with basic and advanced techniques in order to characterize the relations among all the available variables. Then, starting from the results of the data analysis, a linear model has been produced in order to be employed to predict with a certain grade of accuracy the operating conditions of the system.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
A disposição final de resíduos sólidos urbanos, em aterros ou lixões, é um problema das grandes cidades. A utilização do lixo urbano em processos de tratamento térmico com recuperação energética vem ao encontro da busca de fontes alternativas, preferencialmente as renováveis, para a geração de energia. Assim, usinas de incineração com reaproveitamento de energia vêm sendo apresentadas como uma solução tanto para o destino do lixo quanto para a diversificação da matriz energética. Além disso, a prática da incineração proporciona máxima redução da massa e volume e inertização do lixo, estando o aproveitamento energético de resíduos (Waste-to-Energy) dentre as alternativas mais coerentes para a gestão de resíduos sólidos municipais. No Brasil, práticas como esta ainda são incipientes, porém apresentam grande potencial de estudo para aplicações nos centros urbanos em um futuro próximo. O presente trabalho apresenta uma proposta de uma usina lixo-energia, aplicável ao município do Rio de Janeiro, baseada na planta de Zabalgarbi/Bilbao (Espanha), que funciona em ciclo combinado a gás natural e incinera resíduos, aproveitando seu conteúdo energético para produzir eletricidade. Uma análise energética e exergética é realizada juntamente com uma estimativa do custo de geração de eletricidade, influenciada por um indicador de ecoeficiência que leva em consideração as emissões atmosféricas. Como conclusão, mostra-se a capacidade do sistema proposto em destinar os resíduos sólidos urbanos e atender a demanda elétrica do município do Rio de Janeiro/Brasil a um custo competitivo.
The final disposal of municipal solid waste in landfills or dumps is a regular problem to the big cities. The use of municipal waste in processes of thermal treatment with energy recovery meets the search for alternative and renewable sources of energy production. Thus, energy recovery incineration facilities are being presented as a solution to both the waste disposal problem and the growing energy demand in the cities. Additionally, incineration provides the maximum reduction of mass, volume and dangerousness of the waste and the waste-to-energy practice stands out among the most coherent alternatives for municipal solid waste management in the world. In Brazil, however, it is still incipient and therefore presents a great potential for feasibility and application studies in the urban centers. This work presents a proposal of a waste-to-energy facility that could operate in the city of Rio de Janeiro (Brazil), based on the Zabalgarbi/Bilbao (Spain) plant, which operates in combined cycle fueled by natural gas and urban solid waste and generates electrical power. It is performed an energetic and exergetic analysis along with a cost estimate influenced by an eco-efficiency indicator that takes into account the air pollution emissions. The conclusion shows the capacity of the proposed facility to treat the municipal solid waste of Rio de Janeiro (Brazil) and supply its electricity demand with a competitive cost.

Previous studies from laboratory experiments and a similar process at a plant in Switzerland, led to the pilot plant project at Renova AB, which will be described in this master thesis. In cooperation with Götaverken Miljö AB it was investigated if fly ash, produced at the Renova Waste-to-Energy plant in Gothenburg, could be treated with own scrubber liquids in order to recover zinc. If successful, Renova might build this tested pilot process in to a big scale. The pilot plant has a scale of 16 times smaller than a future big scale process. The goal of the project is to leach zinc from fly ash and gain a fly ash residue, which is classified as non-hazardous waste. The filtrate from the leaching campaign is treated so that the containing zinc is recovered. The zinc cake end product shall has a quality so that it can be sold to other industries or upgraded to high purity zinc metal. The evaluation of the experiments showed that the pilot plant process was successful. It was possible to leach out zinc by a maximum quote of 74%. The total recovery of zinc could be achieved by a maximum of 72%. The final zinc cake product was achieved through a precipitation and filtration campaign. This thesis evaluates, which process set-ups for zinc recovery through leaching and precipitation & filtration are the best and can be recommended for a big scale process. In addition, it briefly analyses the zinc product quality. Future studies will be necessary within: cost analysis of the process, zinc product quality and an analysis of the ash residue.

This thesis is about the making of a power plant. It sheds light on how neoliberal ideas shape large public investments in sustainable energy infrastructure. It tells the story of how the City of Copenhagen decided to build what was claimed to be the greenest waste-fired power plant in the world: Copenhill. The plant was to have a ski slope at the rooftop and a chimney puffing smoke-rings. However, conflicting urban visions and rationalities led to a year-long crisis in the project’s planning phase. In the end, Copenhill was built over capacity, which today makes it difficult to match budget and costs. I combined information from internal municipal documents, interviews with decision makers and informal corridor talk to identify the driving forces behind the outcome of the crisis, and the contradictions and complexities of the case. I found that the crisis had roots in the way the public energy company ARC began to act like a private firm, with an entrepreneurial vision. ARC adopted an expansionist growth plan to build a large power plant with iconic architecture. The Copenhill project attracted local politicians wishing to brand Copenhagen as a green world city. However, the city’s Technical and Environmental Administration (TEA) was guided by a managerial vision with a strong sustainability focus. TEA’s analysis showed that there would not be enough garbage in the city to power the over-sized plant. Consequences for economy and environment were seen as potentially disastrous. Supported by city council and government, TEA tried to stop Copenhill. The clash between the two different urban visions led to the formation of two opposing coalitions with each their own rationality. The contradictions between growth rationality and green rationality caused the Copenhill Crisis. The direct intervention of the power élite in support of a growth solution short-circuited the norms of transparent public decision-making. Bowing to political pressure, TEA produced new documents saying that Copenhill would be great for economy and climate. Dark planning practices led to an outcome that was falsely presented as a compromise between green and growth strategies. It was in fact a growth solution, wrapped in green arguments that were not rational. The case study supports a key proposition in theory on the dark side of planning: that rationality is context-dependent and that the context of rationality is power. The case study adds insights to theory by showing the ways neoliberal thought merges with existing socio-economic conditions in space and time, specifically within a Nordic welfare-state context. It shows how public energy companies can face challenges, not only from neoliberal-driven privatization attempts, but also from ideas of iconicity and city marketing. The case study reaffirms the strength of a Flyvbjergian approach to understand the effects of hidden power mechanisms on planning of public energy infrastructure.

PhD thesis deals with the application of the simulation and optimization methods in the waste-to-energy field. An introduction describes the current state of the waste management in the EU with the focus on the Czech Republic. In the following chapter the evaluation criteria for investment intentions and the basic principles of stochastic programming are discussed. The core of the work lays in the mathematical models for the planning and operation of the process plants as well as in the mathematical models for the waste collection. The transportation problem involves all considered technological elements and therefore it is possible to simulate the waste streams between the producers and processors. This approach is demonstrated with five case studies. In the first three studies the calculations for the potential investor are presented. The main outcome of these case studies is the determination of the level of attractiveness of investment and the identification the greatest risks. Another case study is devoted to an analysis with the focus on perspective of government policies and in the last case study the issue of the waste management is analyzed in detail from the perspective of the waste producers. Developed computational tools are flexible and can be further developed and adapted based on the objectives of the specific tasks.

The diploma thesis is focused on the evaluation of small-scale waste to energy plants in the Czech Republic. In the first part, there is a survey of the corresponding literature and general evaluation of the specificities of these plants. The next section analyzes the technical and economic indicators of a specific technology by Microsoft Excel model. Finally, recommendations for small-scale waste to energy plants arising from the model are summarized.

This thesis deals with the evaluation of the strategic investment in the waste-to-energy plant development. The central supply of heat and the incineration plant connection can be provided for example by the distribution network. The objective is to find financially feasible solution regarding uncertain development of waste management and energy market. A heat supplies to district heating network significantly influences the strategic decision. A two-stage stochastic programming based on the scenarios and the GAMS software were applied to solve this task. The main contribution of this thesis is decision on crucial parameters of the waste-to-energy plant.

This thesis is devoted to the construction of new waste-to-energy plants in a territory where is already another fossil-fuel power station in operation. The aim is to create a mathematical model and prove that those two devices are able to cooperate effectively using same technology. Exactly assembled model under real operating have characteristics of a mixed integer nonlinear programming. The optimization software GAMS is used for its calculation. The complexity of the model, however, is at a level that solutions in bad initial conditions ends in local optima, or not found at all. This thesis is devoted to the elimination of non-linearity using binary variables and heuristic so the task was solved with acceptable time limits to guarantee an optimal solution.

This thesis presents the potential of biogas production using food waste collected from the region of Kartamantul in Yogyakarta, Indonesia. Biogas can be used for cooking and generating electricity. The study compares two different end uses or markets for utilizing the biogas in the region. The daily food waste collected in the region of Kartamantul is 120 tonnes. This corresponds to a daily biogas production of 13 087 m3. Electricity generated from biogas can replace fossil-based coal electricity while cooking biogas can substitute the common fossil fuel liquefied Petroleum Gas (LPG). The price for selling one kWh of electricity to the state owned enterprise PLN is 16.5 USD cents. The price for selling one m3 of biogas for cooking is 38.5 USD cents, which is equivalent to the available price of LPG. The study finds that the avoided emission due to the substitution of fossil-based coal electricity and cooking LPG-gas is around 64 GgCO2-eq per year. Considering the economical results for a life span of 20 years in the first utilization option Biogas for Electricity gives a net present value (NPV) of 2 MUSD while for the utilization option Biogas for Cooking gives a net present value (NPV) of 5.82 MUSD. The breakeven for Biogas for Electricity is 13.8 USD cents per kWhe while for Biogas for Cooking is 25.5 USD cents per m3-biogas. The study concludes that it is feasible to invest in AD plant in the region of Kartamantul where both markets are profitable and environmentally friendly.
Denna avhandling visar potentialen för biogasproduktion med hjälp av matavfall som samlats från regionen Kartamantul i Yogyakarta, Indonesien. Biogas kan användas för matlagning och elproduktion. Studien jämför två olika slutanvändningar eller marknader för att utnyttja biogasen i regionen. Det dagliga matavfallet som samlas i regionen Kartamantul är 120 ton. Detta motsvarar en daglig biogasproduktion på 13 087 m3. Elektricitet som genereras från biogas kan ersätta fossilbaserad koldioxid, medan tillagning av biogas kan ersätta det gemensamma fossila bränslet flytande petroleumgas (LPG). Priset för att sälja en kWh el till det statligt ägda företaget PLN är 16,5 USD cent. Priset för att sälja en m3 biogas för matlagning är 38,5 USD cent, vilket motsvarar det tillgängliga priset på LPG. Studien konstaterar att den undvikna utsläppet på grund av substitutionen av fossilbaserad kolkraft och matlagning av gasol är cirka 64 GgCO2-ekv per år. Med tanke på de ekonomiska resultaten för en livslängd på 20 år i det första utnyttjandegradet ger Biogas for Electricity ett nettopåverkande värde (NPV) på 2 MUSD medan för utnyttjandegraden Biogas for Cooking ger ett nettoförskott (NPV) på 5,82 MUSD. Breakeven för biogas för el är 13,8 USD cent per kWhe medan för Biogas for Cooking är 25,5 USD cent per m3-biogas. Studien drar slutsatsen att det är möjligt att investera i AD-anläggningar i regionen Kartamantul där båda marknaderna är lönsamma och miljövänliga.

The aim of this thesis is the design of municipal waste incinerator using the generated steam for power generation and distribution of heat. At the beginning is engaged in development of waste issues and the current state of waste management. The next section describes the options of waste treatment and possible solutions to the current state of waste issues. The concept of waste incineration plants: For waste incineration is used line for burning 100,000 tons of municipal waste per year.Combustion takes place in a grate boiler. Its advantage is the versatility and flexibility to waste. Electricity generation is dealt with condensing turbine with controlled consumption. The flue gas cleaning is designed to semi-wet method. The final stage involves the calculation of the balance, the calculation of electric energyand basic economic evaluation.

The diploma thesis deals with an increasing of utilization of energy during a combustion of waste. The introductory part deals with a presentation of the specific waste to energy unit and its combined heat and power production. In the next part is described a computing tool and the principle of its function. The main part od the thesis deals with a description of cumputing tool testing and with a summary of achieved results.

High temperature corrosion of the heat exchanger materials is the important factor that limits the efficiency of various energy systems. The problem becomes more serious when fuels containing alkali metal, heavy metals, chlorine, and sulphur are used. In combustion systems utilizing biomass and municipal solid waste, the steam temperatures are kept lower than 450"C in order to avoid the corrosion problems. This results in low overall plant efficiencies (e.g. 25 - 30%). Therefore, methods to prevent or control high temperature corrosion in these plants must be investigated.

The main aim of this thesis is to create a sequence of mathematical optimization models with different levels of complexity for the efficient management and waste energy utilization. Stochastic programming approach was utilized to deal with random demand and uncertain heating values. Hence, more applicable model of the waste-to-energy plant has been developed. As the next step, the model is enhanced by heating plant extension. Computations are realized for real-world data and optimal solution is found by using GAMS implementation.

This master´s thesis deals with an air cooled condenser. The specific attention is focused on the condenser in the Brno´s waste-to-energy plant SAKO. The general process of calculation of the heat transfer coefficient is introduced, which is the base for the calculation of the condenser´s output. This process is later used for the calculation of a specific condenser. A considerable part of the thesis is concentrated on the analysis of behavior of the condenser of SAKO in various conditions from the theoretical point of view and then also in terms of real operation using provided operational data.

Analysis of the regional energy supply, shows that suitable alternative may be a combination of primary energy sources with the municipal solid waste to energy plant. Starting from the fact that the regional thermal energy needs are characterized by smaller power demand, but relatively significant seasonal fluctuations in heat supply. These factors limit the processing performance of the considered waste to energy plant that could be included in the system of regional energy supply. The aim of the thesis was to propose adequate treatment capacity for regional waste to energy plant and explore alternative solutions in off-gas cleaning for exhaust gases generated during incineration of MSW. The balance sheets of two alternative solutions off gas cleaning are part of the thesis, both in terms of material and energy consumption. Presented evaluation of economic demands alternative arrangement of off gas cleaning includes operating costs and the impact on earnings from energy production.

Au cours des dernières décennies, le contrôle de la corrosion des alliages exposés à des conditions sévères et complexes a été un grand défi pour les applications industrielles. Les coûts de la corrosion sont élevés et les stratégies de prévention sont devenues une demande industrielle importante. Le projet SCAPAC financé par l’ANR, a proposé d’étudier la corrosion lors de deux procédés industriels: le vapo-réformage du méthane et l’incinération des déchets ménagers. Bien que les conditions de fonctionnement de ces deux procédés soient différentes, les approches de modélisation peuvent être similaires. Dans le procédé de vapo-réformage du méthane, les composants métalliques sont soumis à la corrosion par « metal dusting », qui est une forme d’endommagement catastrophique qui affecte les alliages exposés à des températures élevées (400-800 °C) et des atmosphères sursaturées en carbone. De même, les composants métalliques des incinérateurs de déchets qui sont exposés à des atmosphères de combustion sont soumis à la corrosion à haute température sous dépôts de cendres. Le « metal dusting » est un phénomène critique qui a mené à des pertes matérielles importantes et à l’arrêt d’installations industrielles pendant les 50 dernières années. Les mécanismes de cette dégradation ont été identifiés et sont disponibles dans la littérature. Cependant, l'effet de certains paramètres des procédés ne sont pas encore bien compris et nécessitent des compléments d'études. En ce qui concerne la corrosion à haute température, les mécanismes sont bien documentés et une quantité considérable de travaux ont été publiés au cours des dernières décennies. De nombreux matériaux et revêtements ont été développés. Cependant, la performance des matériaux dans des environnements différents n'est pas assez bien comprise pour créer des modèles de prédiction de durée de vie. Une revue bibliographique de ces deux domaines a révélé qu’il existait des approches de modélisation. Néanmoins, il n'y a pas actuellement de modèle prédictifs fiables de durée de vie qui soit disponible dans la littérature pour les alliages commerciaux, et pour une gamme étendue de conditions expérimentales. La présente étude présente une méthodologie pour développer des modèles statistiques de prévision de durée de vie. Il s’agit d’évaluer la performance de matériaux soumis au « metal dusting » et à la corrosion à haute température sous dépôt. Deux bases de données ont été construites pour intégrer les résultats expérimentaux du projet SCAPAC, aussi bien que résultats de la littérature. Ceci afin d’avoir suffisant des données pour la modélisation. Ces bases de données ont permis d'analyser plus de 4000 vitesses de corrosion à l’aide de méthodes statistiques appliquées à différents scénarios. La méthodologie de l’Analyse des Composantes Principales (ACP) a été utilisée pour identifier les paramètres clés des mécanismes de corrosion, qui ont été ensuite utilisés pour construire des modèles de prédiction de durée de vie par Régression Linéaire Multiple (RLM). Pour la corrosion à haute température, trois modèles ont été obtenus dans le scénario de gradient thermique pour trois familles d'alliages: des aciers ferritiques, des alliages austénitiques à base de fer et nickel et des alliages à base de nickel, en montrant des résultats encourageants. Pour la corrosion par « metal dusting », deux modèles ont été obtenus pour expliquer le temps d'incubation et la cinétique croissance de profondeur de piqures, avec des résultats satisfaisants. Les modèles statistiques dans les deux cas ont été comparés avec deux résultats expérimentaux et théoriques montrant un bon accord, qui permet l'évaluation de la durée de vie des matériaux dans les conditions définies
Over the last decades, the corrosion control of alloys exposed to severe and complex conditions in industrial applications has been a great challenge. Currently, corrosion costs are increasing and preventive strategies have become an important industrial demand. The SCAPAC project funded by the French National Research Agency has proposed to study the corrosion for two separate processes: Steam Methane Reforming (SMR) and Waste to Energy (WtE). Although the operating conditions of both processes are different, the modeling approaches can be similar. Metallic components in the SMR process are subjected to metal dusting corrosion, which is a catastrophic form of damage that affects alloys exposed to highly carburising gases (aC>1) at high temperatures (400–800 °C).[1]. Likewise, metallic components in the Waste to Energy (WtE) process are subjected to high temperature corrosion under deposit that takes place in equipment exposed to atmospheres with high content of corrosive products of combustion. Metal dusting corrosion is considered as a critical phenomenon that has led to worldwide material loss for 50 years. A basic understanding of the degradation mechanisms is available. However, the effect of some process parameters is still not well understood in current literature and requires further study. Otherwise for high temperature corrosion, a considerable amount of literature has been published over the last few decades and the mechanisms are well documented. Also many materials and coatings have been developed. However, the material performance in different environments has not been sufficiently well understood to define suitable criteria for lifetime prediction models regarding operating conditions, due to the high complexity of the corrosion phenomena involved. Literature research in both fields revealed modeling approaches in different kinds of complex conditions and applications. Nevertheless, there are no lifetime models currently available in the open literature for commercial materials that consider a wide range of conditions and the relative weight of the variables involved in the corrosion processes. This dissertation presents a methodology to develop lifetime prediction models to evaluate materials performance under metal dusting and high-temperature corrosion conditions. Two databases were created to integrate experimental results from the SCAPAC project, as well as results from literature to enable sufficient amount of data for modeling. The databases allowed analyzing approximately 4000 corrosion rates by different statistical methods over different scenarios. The Principal Component Analysis (PCA) methodology was performed to identify the key parameters to create lifetime prediction models using Multiple Linear Regressions (MLR). For high-temperature corrosion, three models were obtained in the thermal gradient scenario for three families of alloys: low alloyed steels, Fe/Ni-based high temperature alloys and Ni-based alloys, showing agreeable results. For metal dusting corrosion, two models were obtained to explain the incubation times and the kinetic of pit depth growing, showing satisfactory results. The statistical models in both cases were compared with experimental and theoretical results showing good agreement with experimental findings, which allows performing the lifetime assessment of materials under defined conditions

Fossil fuel depletion, economic development, urban expansion and climate change present tough challenges to municipal- and regional-scale energy systems. Regional energy system planning, including waste treatment, renewable energy supply, energy efficiency, and climate change, are considered essential to meet these challenges and move toward a sustainable society. This thesis includes studies on energy system from municipal waste, potential for a fossil fuel-independent regional energy system with increased renewable energy products using waste as one of energy sources, and the performance of biomass-fired combined heat and power (CHP) plants. A top-down method is adopted to organize the studies, from national waste-to-energy (WtE) scenarios to individual energy plants. The first study considers the overall potential contribution of WtE to energy supply and greenhouse gas (GHG) emissions mitigation in Sweden until 2050 under several different scenarios. Depending on WtE scenario considered, the study shows that WtE can supply energy between 38 and 186 TWh and mitigate between CO2 of 1 and 12 Mt per year by 2050 based on the baseline of year 2010. At a regional level, static and dynamic optimization models with a focus on WtE are developed for two regions in Sweden and Finland. The former is used to investigate the possibilities of optimal positioning of new energy plants, retrofitting existing energy plants and planting energy crops. The latter case study is on regional heat and power production using biogas generated from agricultural and livestock wastes. Centralized biogas production units perform better than distributed production regarding energy and carbon balance though the net energy output is negligible. However, a significant GHG emission can be reduced compared to the present status. Retrofitting existing conventional CHP plants is another option for improving regional energy system. The study shows that integrating heat-demanded processes such as drying, bioethanol and pellet production with existing CHP plants can improve overall energy efficiency and power output, increase annual operation time and reduce production cost as well as mitigate GHG emissions.  It is recommended that building new WtE/energy plants at optimum sites, upgrading the existing energy plants, expanding the agricultural/forestry waste/residues output (biomass) and planting more energy crops shall be taken into considerations for the future regional energy systems.
Utarmning av fossila bränslekällor, ekonomisk utveckling, städernas utbredning och klimatförändring är svåra utmaningar för kommunala- och regionala energisystem. Planering av det regionala energisystemet, inklusive avfallshantering, förnyelsebara energikällor, energieffektivisering och hänsyn till klimatförändringar, anses avgörande för att möta dessa utmaningar och gå mot ett hållbart samhälle. Denna avhandling innehåller studier av energisystem centrerad kring hushållsavfall, potentialet för fossilbränslefria regionala energisystem som utnyttjar ökad andel förnyelsebara energiprodukter med avfall som en energikälla och prestandautvärdering av ett biomassa-eldat kraftvärmeverk. Studierna har organiserats efter storlek på system, från nationella avfall-till-energi scenarier till enskilda kraftverk.   Den första studien behandlar övergripande möjligheten att genom avfall-till-energi bidra till energiförsörjningen och begränsa utsläppet av växthusgaser i Sverige till 2050 under flera olika scenarier. Beroendet på avfall-till-energiscenario visar studien att genom att utnyttja avfall kan mellan 38 och 186 TWh energi levereras och dessutom kan koldioxidutsläppen reduceras med 1-12 miljoner ton till år 2050 med 2010 som basår.   På den regionala nivån, statiska och dynamiska optimeringsmodeller, med fokus på avfall-till-energi, är utvecklats för två regioner, en i Sverige och en i Finland. Det första modellen används för hitta den optimala placeringen av nya energianläggningar, anpassning av befintliga anläggningar och placering av odlingar av energigrödor. Den senare ingår i en fallstudie av den regionala kraft- och värmeproduktionen genom utnyttjande av biogas producerad från jordbruksavfall och djurgödsel. Centraliserade biogasanläggningar presterar bättre än decentraliserad anläggningar när det gäller energi – och kolbalanser även om i båda fallen så är skillnaden mellan konsumerad mängd bränsle, värme och el och producerad värme och el försumbar. Däremot kan en betydande mängd av växthusgasutsläppet i båda fallen undvikas jämfört med nuläget.   Anpassning av befintliga konventionella kraftvärmeverk är ett annat alternativ för att förbättra det regionala energisystemet. Studien visar att genom att integrera värmekrävande processer såsom torkning, bioetanol- och pelletsproduktion med befintliga kraftvärmeverk kan den totala energieffektiviten och uteffekten förbättras, öka den årliga drifftiden och minska produktionskostnaderna och utsläppen av växthusgaser.   Rekommendationen är att för de framtida regionala energisystemen överväga att bygga nya avfall-till-energianläggningar med optimal placering, uppgradera befintliga energianläggningar utöka insamlandet av avfall/restprodukter från jord- och skogbruk och plantera mer energigrödor.

The rural areas in the Gaza Strip suffer from the problem of sanitation and organic waste as well as electricity and cooking fuel. In this thesis, the biogas plant was designed to solve those problems based on the fixed dome plant design as shown in Figure 3 and4. Therefore, the efficiency and selectivity was good for biogas plant which is easy for the local people disposal of organic waste and wastewater as well as self-sufficiency of biogas for cooking and electricity for the family. The sediments from the biogas plant are also used as fertilizers in agriculture. Thus it is possible to know the amount of biogas production, the cost of biogas, the amount of fertilizer, the cost of fertilizers and the amount of disposal of organic waste and wastewater. The calculation shows that the size of digester which is equal to 12 cubic meters as shown in figure 4.The construction is cost of $ 930 as shown in Table 2. Through the results will be disposed of organic waste, wastewater and manure are about 48 kilograms per day for the family. The Biogas is produced 0.5 tons of biogas is estimated about $ 100 in rural areas in the Gaza Strip. It is also produced fertilizers equivalent of $ 113 per month. So the results and calculations are clear that the rural family is self-sufficient of biogas, the dispose of organic waste and wastewater and agricultural growth by the fertilizers from the biogas plant.

The topic of the diplome thesis is draft of the waste-to-energy plant for municipal waste with cogeneration of heat. Basic specification of project: Waste-to-Energy plant is facilitated by two rotary kilns of type operating in parallel. Further flue gas leaving the post-combustor enters a multicyclone unit to separate substatial portion of fly-ash. Heat of flue gas at the temperature of 1000°C generates superheated steam in a Heat Recovery Steam Generator (HRSG). Dry sorption process is appllied for flue gas treatment. Specifically sodium bi-carbonate is used for it. Products of reactions and remnants of dust are separated by a baghouse. Superheated steam, generated by two HRSG, presents the inlet stream of a condensing steam turbine with steam extraction. The diploma thesis contains calculation of major devices and basic economical and financial statement of project.

碩士
國立臺灣海洋大學
系統工程暨造船學系
96
Water tube boiler is one important component in modern waste to energy facility. From 1970’s government of Taiwan started to construct mega-incinerator for each county, till completion of Iilan & Keelung facility, each single project faces different problem in construction & operation. Boiler water tube corrosion always play a main issue in operation. This thesis try to analysis the boiler water tube corrosion from high temperature corrosion mechanism comparing to real corrosion data.

A design project submitted in partial fulfilment for the degree of Master of Architecture (Professional) at the University of the Witwatersrand, School of Architecture & Planning, University of the Witwatersrand, 2020
South Africa is currently going through an energy crisis; our energy infrastructures are being utilised into full capacity. This tells me that infrastructures will be questioned and its ability to meet societal demands are a matter of concern. This crisis is linked to an increasing demand of the energy service that is linked back to population urban growths. This is informed by a larger issue and that is the global issue of climate change; this environmental phenomenon is forcing our position to reconsider primitive industrial systems, unfortunately for the sake of urban and environmental spaces, this crisis as a physical effect. However, there is one thing that stands out from this crisis of climate change and that is waste. This component was once regarded as the output of industries, it had no societal value and because we dwell in spaces of old constructs. We are forced to value consumption more than the production of waste. What if we shifted our thinking and placed a commodity value on waste? Landfills are a testament to our waste outputs and more so the proof that waste is renewable as it is always available in every Industry. If we can manage our waste for the purpose of generating energy, this will be a contribution towards sustainability and the bigger issues of climate change. The idea of sustainability must be mutually important to society. This thesis proposes the design of a waste to energy plant system in Modderfontein. The design is linked to the contextual landscapes of Modderfontein and these are mapped as the natural landscape, industrial landscape and the growing housing landscape. The logistics of waste collection are synchronised to the local community of Modderfontein and the Landfills in Johannesburg. This means that through this better system we can transpire shared values and beliefs of sustainability at a communal scale whilst significantly implying a notion of sustainable and better energy infrastructure. We should question existing energy infrastructure and existing systems; in particular, the spatial qualities that state owned facilities provide. We need a better spatial environment for public infrastructure, a space where the industrial, natural and the human component can coexist through Architecture. Can we LIVE, WASTE and FUEL all in one Architectural system?
CK2021

碩士
崑山科技大學
環境工程研究所
98
At present in Taiwan, the main principal of waste treatment is “major for incineration, minor for landfill”, which is also dependent on the integrated regional planning as well as urban development. Until 2010, there are 24 incineration plants, including 5 by “public owner public operation” and others by “public owner private operation”. The policy of “public owner private operation” concerns governmental finances and human power. This study first collected related literature, including laws and policies of environmental protection and others. Two case-study plants, one for “public owner private operation”, another for “public owner public operation”, are selected to compare with their differences. Discussion of the performance is focused on the indicators of cost-benefit analysis, human-power efficiency, service efficiency, goal-achievement rate, energy recovery, and annual operation of incineration. The results show all the indicators of “public owner private operation” are better than those of “public owner public operation”. This can benefit the government for reducing financial loading.

Waste-to-energy (WTE) is the environmentally preferred method of managing post-recycling wastes. In this process, municipal solid waste is combusted under controlled conditions to generate steam and electricity. Waste is by nature heterogeneous and has a substantially high composition of chlorine (0.47-0.72 wt%) as compared to other solid fuels used for power production. During combustion, chlorine is converted to hydrogen chloride and metal chlorides, which can accelerate the high temperature corrosion of boiler surfaces, especially superheater tubes. This corrosion can significantly affect plant efficiency and profitability by causing unplanned shutdowns or preemptively forcing operators to limit steam temperatures. The following work focuses on the role of chlorine compounds on boiler tube corrosion and investigates approaches for minimizing its effects. The corrosion behavior was studied by conducting laboratory furnace tests on alloys of current and future interest to the WTE industry. Test specimens were coupons machined from boiler tubes to a nominal area of 3.2 cm² (0.5 in²). An chemical environment was introduced in an electrical furnace that replicates the fireside of superheater tube. This included a mixed gas stream with O₂, CO₂, H₂O, HCl, SO₂, and N₂, and temperatures ranging between 400-550°C (752-1022°F). For some experiments, a salt layer was applied to the coupons with a loading of 4.0 ±10% mg/ cm² to understand the behavior of the effects of metal chlorides. Following each experiment, the corrosion rate was determined by taking the mass loss as specified in an American Standard Testing Method (ASTM) protocol, G1-09. Additional insights were obtained by characterizing the coupons via scanning electron microscopy (SEM) and elemental dispersive spectroscopy (EDS). Additionally, the corrosion scale and salt layer were characterized via powder X-ray diffraction (XRD). The addition of 800 ppm of hydrogen chloride (HCl) gas to a mixed gas oxidizing environment accelerated the corrosion rate of SA178A (Fe-0.1C) at 500°C (932°F) as determined by the change in the parabolic rate constant over a period of 72 hours, from 0.18 to 1.7 μm²/h (3.0 E-03 to 2.5 E-02 mil²/h). The findings from the EDS and XRD scale analyses were compared to other literature and thermodynamic calculations that showed that effect that HCl accelerates corrosion via an active oxidation mechanism. A parametric study was performed on the effect of hydrogen chloride on three alloys, SA178A, SA 213-T22 (2.5 Cr-1 Mo-Fe) and NSSER-4 (Fe-17Cr-13Ni). Varying the concentration from 400 ppm to 800 ppm at 500°C increased the mean mass loss by 17.5%, as compared to the 60% increase from 0 to 400 ppm. For each alloy, the mass loss increased sharply with temperature between 450, 500, and 500°C, with corresponding apparent activation energies of Ea NSSER- 4 53 kJ/mol, Ea SA213 T22 110 kJ/mol, and Ea SA178A 111 kJ/mol. The lower apparent activation energy for NSSER-4 demonstrates that effect of hydrogen chloride is mitigated with austenitic alloys versus carbon steel or low alloyed steel. In a comparative study between isothermal and temperature gradient tests, it was also shown that the corrosion of SA178A was not impacted by a temperature gradient up to 250 °C. Another important chlorine compound in WTE boilers are metal chlorides, which are readily contained in fly ash and boiler deposits. Using sodium chloride as a surrogate compound, the corrosion behavior under chloride salts was investigated by applying a salt layer (4.0 mg/cm²) on coupon surfaces. Corrosion under the chloride layer was much more severe than below the HCl-containing atmospheres alone. The mass loss for the commercial steels was increased by more than an order of magnitude. Based on SEM and XRD coupon and corrosion product characterization, this behavior was the result of a second active oxidation mechanism in which sodium chloride reacts with and depletes protective oxides such as chromium (II) oxide. The WTE furnace tests with the sodium chloride layer were executed for six different Ni-Cr coatings, including Inconel 625 (Ni-Cr-Mo), SW1600, SW1641 (Ni-Cr-Mo-B-Si) and Colmonoy 88 and SP 99 (Ni-Cr-B-W). The primary corrosion attack observed was pitting located under the original salt layer. Colmonoy 88, showed superior corrosion resistance with mass losses between 0.3-3.1 mg/cm2 between 450-550°C as compared to the Ni-Cr-Mo, and Ni-Cr-B-So coatings which has mass losses between 10-30 mg/cm². The enhanced corrosion performance of Colmonoy 88 and SP 99 was attributed to the alloying addition of tungsten, which had been previously shown in literature to also improve the pitting resistance for Ni-Cr in aqueous environments. The corrosion behavior under metal chlorides was compared with metal sulfates, which are also prominent in WTE fly ash and boiler deposits. The application of sulfate salts on coupon surfaces was shown to semi-protective on WTE boiler tube surfaces up to temperatures of 550°C. The mass loss for carbon steel and Fe-17Cr-13Ni (NSSER-4) below sodium sulfate was an order of magnitude lower than under sodium chloride. These results motivated experiments aimed at sulfating chloride boiler deposits by increases the sulfur/chlorine gas ratio (SO₂/HCl) in WTE fuel gas. The SO₂/HCl ratio was modified between 0.3 to 0.6 and 1.0 respectively. By increasing the SO₂/HCl ratio, the sodium chloride layer applied on the coupon surface was converted from a chloride rich salt to a sulfate rich and was shown to dramatically reduce the corrosion of tube alloys up to 500°C. The impact of sulfating the alloy was most prominent with alloys with high mass loss under the sodium chloride layer. Tests showed a reduction in the corrosion rates of SA213 T22 (37%), Inconel 625 (23%), and NSSER-4 (27%). At 550 °C, there was no trend with respect to increases of the ratio, which suggests that other corrosion reactions are faster than the rate of sulfation. Finally, the annualized cost factor was defined and proposed as a method for replacing current superheater alloys with alternative materials, such as those tested in this thesis. From this discussion it was calculated that the installation of a colmonoy 88 protected superheater can cost approximately 1.4 times the cost of an Inconel 625 cladded replacement, or as much as 4.3 times the cost of a T22 superheater tube and remain a cost effective option.

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An economizer is normally employed to perform heat recovery from hot exhaust gases to cold fluid. In this work, a newly designed economizer is devised to achieve high heat recovery in a pasteurized milk plant. In the economizer, the hot exhaust gas is divided into two channels flowing up on the left and right sides. After that, it is moving down passing over aligned banks of tubes, which water is flowing inside, in a triple passes fashion. Moreover, three dimensional (3D) models with heat transfer including fluid dynamic have been developed, validated by actual plant data and used to evaluate the performance of the economizer. Simulation results indicate that the newly designed economizer can recover the heat loss of 38% and can achieve the cost saving of 13%.

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfilment of the requirement for the degree of Doctor of Philosophy in Engineering, 2020
Conventional biomass gasification is associated with technical issues which limit its scale-up to full commercialization. These issues include but are not limited to high tar composition in the syngas produced, low syngas yield, and expensive and inefficient tar cleaning procedures. Biomass pyro-gasification can be defined as a hybrid or multi-stage integration of pyrolysis and gasification process, controlled independently to separate and restrict tar from being gasified alongside char. This is capable of producing high yields of syngas with less tar impurities suitable for downstream applications. By employing pyro-gasification, this research aimed to investigate the properties of syngas contained in the product gas, produced from the thermochemical conversion of wood wastes. These enormous wood wastes samples were sourced from different Invasive Alien Plants (IAPs) and commercial sawmill tropical woods. Firstly, the individual samples were subjected to a series of characterisations to ascertain their fuel properties and suitability for pyro-gasification. These tests include their structural composition, proximate and elemental composition, char yield, char reactivity, higher heating value (HHV), bulk density, fuel ratio, and energy density. A fuel quality evaluation of the samples was conducted to rank the samples accordingly. This was used to gain better understanding of the behaviour of each sample when subjected to pyro-gasification. Furthermore, the samples were subjected to a thermogravimetric analysis to ascertain their rates of volatilization, char decomposition, and maximum decomposition temperatures. Based on their thermogravimetric analysis and differential thermogravimetry, a kinetic study was conducted to inform the viability of the samples and the selection of suitable operating parameters for optimum process efficiency. Finally, in conducting the pyro-gasification experiment, the sawdust sizes of the wood waste samples were first pyro-gasified individually (i.e. 100% wt. of the feedstock). Subsequently, the samples were blended with each other in three separate mix ratios – 30/70 (i.e. 30% wt., and 70 % wt. of 20 g of the feedstock), 50/50 and 70/30. The product gas produced from each experimental run was sampled at 900°C, 950°C, and 1000°C, and analysed using a TCD Gas Chromatograph (GC). The properties of the syngas (and those of its component gases CO and H2) determined are the – percentage concentration in the product gas, syngas yield per gram of biomass feedstock, volumetric flow rate, rate of production of the gas and the physical properties of the flame generated when the syngas was ignited. According to the data collated, syngas concentrations in the product gas were generally high across the board, averaging 96.4%. Meanwhile, trace concentrations of CH4 and CO2 were observed in the product gas. The ratio of H2/CO in the syngas averaged 0.06 at 900°C and was observed to increase to averages of 0.16 and 0.46 with increase in temperature to 950°C and 1000°C respectively. The production rate of the syngas and those of its gaseous components – H2 and CO, were also affected by the increase in temperature. The most significant increases in the gas production rate were observed with the H2 as the temperature was increased from 900°C to 1000°C. In general, the IAPs showed the highest increases in H2 production rate, attaining significant increases with the rise in temperature from 900°C to 1000°C. The 100% wt. of the Poplar feedstock, in particular, exhibited a significant increase in H2 production rate from 130.12 mL/min/gram at 900°C to 3556.14 mL/min/gram at 1000°C. Meanwhile, the highest hydrogen production rate of 7937.07 mL/min/gram attained across the board was exhibited by the Eucalyptus-Jacaranda 30/70 blend. Most IAP blended samples exhibited higher syngas production rate than their associated individual samples at a lower temperature of 900°C. However, with an increase in temperature to 1000°C, the syngas production rate from most of these blended samples declined significantly. The syngas yields (i.e. the volume of syngas produced from a gram of wood feedstock), from most samples were significantly high, particularly at 900°C. These yields were subsequently increased at 1000°C. The highest syngas yield of 744.42 mL/gram was obtainable from the Eucalyptus-Bugweed 30/70 blend, while the lowest yield of 518.05 mL/gram was obtainable from the Jacaranda-Poplar 30/70 amongst all IAP samples and their blends. Meanwhile, among the tropical samples and their blends, the highest syngas yield of 735.8 mL/gram of feedstock was obtainable from the Mahogany-Opepe 30/70 blend, while the lowest yield of 493.7 mL/gram of feedstock was obtainable from the African mahogany-Opepe 70/30 blend. These were generally higher than those obtained from the 100% wt. of the individual tropical wood samples. This thesis has been carefully documented to (a) prove the viability of pyro-gasification as a tar removal process for syngas production at reduced gasification temperatures; (b) showcase the viability of wood wastes of invasive alien plants and commercial tropical trees which are yet to be explored for syngas production and; (c) showcase the possibility of optimizing syngas production by blending two wood species in different mix ratios. Some of the findings on results of the characterization of the samples, their thermogravimetric analyses, as well as data on their syngas production via pyro-gasification as described in chapters four, five and six respectively, have either been communicated as scientific articles in journals, presented in conferences or have been submitted and awaiting publication (see Appendix C for this list)
CK2021