Tesis sobre el tema "Cola Co"

Mestrado em Contabilidade, Fiscalidade e Finanças Empresariais
O presente trabalho propõe-se realizar a comparação entre dois métodos distintos de avaliação de empresas - Discounted Cash Flow (DCF) e o Market Value Added (MVA), demonstrando a aplicabilidade destes dois modelos de avaliação no caso da Coca-Cola Co. É possível verificar que o disposto na literatura não é consensual. Da mesma maneira que há autores que defendem a utilização do DCF, existem outros que aconselham a utilização do MVA. Dada a falta de concordância em relação aos mencionados métodos, este trabalho pretende, também, contribuir para o presente debate. Para tal, foi realizada uma análise estratégica e financeira da empresa e do setor com base nos dados financeiros disponíveis relativos ao período de 2014 a 2018 e foram estimados os Free Cash-Flows (FCF) e o Economic Value Added (EVA©) para 2019-2023. Deste modo, foi possível estimar o valor da empresa pelos métodos do DCF e do MVA Os resultados obtidos nos dois métodos foram comparados entre si concluindo-se que os mesmo não coincidem, apesar do apresentado na literatura. Além disso, estes resultados foram comparados com o valor de mercado das ações da Coca-cola, Co. a 31 de dezembro de 2018 e apontaram para uma melhor estimação por parte do DCF em relação ao MVA.
This paper proposes to compare two different companies? valuation methods - the Discounted Cash Flow Method (DCF) and the Market Value Added (MVA), demonstrating the applicability of these two valuation models in the case of Coca-Cola, Co.. It?s possible to verify that the statements in the literature are not consensual. At the same time that some authors defend the use of DCF, there are others who advise the use of MVA. Given the lack of agreement in relation to the aforementioned methods, this work also intends to contribute to the present debate. To this end, a strategic and financial analysis of the company and the sector was carried out based on the available financial data for the period from 2014 to 2018 and Free Cash-Flows (FCF) and Economic Value Added (EVA ©) were estimated for 2019 to 2023. In this way, it was possible to estimate the company's value using the DCF and MVA methods. The results obtained in both methods were compared with each other, concluding that they do not coincide, despite the arguments presented on the literature. In addition, these results were compared to the market value of Coca-Cola, Co.'s shares at December 31st, 2018 and pointed a better estimation from the DCF relatively to the MVA.
info:eu-repo/semantics/publishedVersion

The work presented in this thesis was carried out with a particular view of enhancing the of coal fired fluidised bed hot gas generator (HGG) at the Cantley factory of British Sugar. It covers combustion of coal and biomass and their blends also called co-firing in a fluidised bed combustor. Particularly it focuses on the effect of introduction of moisture as part of fuel or injection of water into the bed on the reduction of excess air to get a stable bed temperature. Although this thesis is focused on increasing the throughput of the HGG, the study has a broad application and can be beneficial in utilising relatively cheap, poor quality, unprepared biomass materials. The results of this study can be helpful in devising systems to deal with wastes from different industries in co-combustion with a fuel of higher calorific value such as coal. Thus the study will have dual impact on the industry; addressing waste management issues on one hand and producing useful energy on the other. This may contribute towards meeting the targets of Kyoto Protocol by reducing emissions of carbon dioxide (COi) as biomass is thought to be COa neutral. The fluidised bed at Cantley is used to dry animal feed and has a design capacity of 40 MW but due to limitations of flow of fluidising gases caused by high flow resistance through sparge pipes, the combustor is running under capacity. Consequently, some of the animal feed has to be dried by using expensive oil fired drier. In any combustion system excess air is used to control combustion temperature. In fluidised bed combustion excess air is used to control bed temperature. If the bed is cooled by other means the requirement of excess air can be reduced. This is the basic idea behind this study which is aimed at enhancing the capacity of the HGG by cooling the bed and thus reducing excess air requirements. The excess air thus spared can be used to combust more coal in the bed and thus will reduce dependence on oil fired dryer and will have financial benefits for British Sugar. Different fuels including wood pellets, wood chips and sugar industry by-products such as vinasse, raffinate and pressed pulp were fired/cofired with Thoresby coal in a fluidised bed test rig installed at the University of Glamorgan. The blends of wood chips and pressed pulp with coal are co-fired at different moisture contents. The tests were conducted at different thermal inputs at a wide range of excess air levels. Most of the work is focusedon the combustion of blends of coal and pressed pulp in different proportions. It was found that the maximum proportion of the pressed pulp in the blend with coal which could be burned successfully in the fluidised bed is 50%. During combustion of different coal-pulp and coal-wood chips blends it was found that excess air requirement is reduced by around 20% in comparison to coal only firing, over the range of the operating conditions tested. Because of the presence of potassium in pressed pulp, which could cause agglomeration during combustion in fluidised beds, longer term tests were carried out with 50/50 blend of coal and pulp. No signs of agglomeration were observed when the rig was fired for 8 days for almost 7 hours a day. However, Scanning Electron Microscopy (SEM) analyses of bed samples taken at the end of every day have shown the accumulation of potassium in the bed up to 1%. For comparison purposes tests were also carried out by co-firing coal with raffiante and vinasse and then it was observed that the bed defluidised relatively quickly, within 40 minutes of co-firing. Post experiment SEM analysis confirmed the accumulation of potassium in the bed which was found to be around 8% for raffinate and around 10% for the vinasse experiment. It was found that the pulp is difficult to deal with and particularly its feeding into the fluidised bed could be a potential problem. Therefore, injection of water into the bed, a relatively cheaper and adaptable option, was also investigated. It was found that emissions of carbon monoxide due to incomplete combustion or water gas shift reaction would not be a problem as long as the bed temperature is controlled above 800 °C. It was found that the injection of water at a rate of 4.5 1/h into the bed fired at 17 kW reduced the air flow requirement by around 7.5 m3/h which corresponds to a reduction of almost 20% which agrees with the finding with coal-pulp blends co-firing. This excess air can be used to burn around 5 kW equivalent of more coal and thus result in an increase in the thermal capacity by around 30%. Therefore, it may be possible to enhance the thermal capacity of the HGG at Cantley by 30% by injecting water into the bed or by co-firing coal and pulp.

Sustainability, security of supply, and diversity, as well as economic competitiveness are key components of energy policy. There is increasingly stringent legislation on the environmental impact of energy production, and there is growing pressure to reduce not just NOx and SOx emissions, but also C02 emissions. For both heating and electricity production it is likely that the plants will need to be fuel-flexible and could use one or more of several different feedstocks, for example coal and biomass. When coal is co-utilized with biomass there is added attractiveness because the biomass is C02 neutral, and there is interest in using wood waste, short rotation woody crops (e. g. willow coppice), or herbaceous crops (e. g. Miscanthus), refuse and waste derived fuels, or wastes such as sewage sludge or chicken litter. The co-utilisation of coal and biomass for heat and/or energy production results in pollutant reduction. Most notable is the impact on the emission of NOx, SOx, volatile organic compounds and polyaromatic hydrocarbons. These latter compounds largely arise from their formation and release during incomplete combustion/gasification. There is evidence that co-firing or co-gasifying coal and biomass results in a significant decrease in the emission of these compared to coal alone. The synergistic activity observed for toxic organic emissions is not well understood and is thought to involve chemical interaction between the volatiles from each fuel coupled with possible catalytic activity from the inorganic constituents of the fuels. Laboratory scale data on synergies in co-pyrolysis is conflicting. Characterisation of co-pyrolysis products from coal and biomass pyrolysis has received limited attention and the data is conflicting. Therefore this thesis seeks to understand possible interactions occurring during co-combustion and co-pyrolysis of fuels and looks at a number of variables, including coal rank, biomass type (with different amounts of catalytic components), heating rate, residence time and the physical form of the fuels. A better understanding of the factors influencing non-additive interactions may lead to optimization of the blending process and minimisation of toxic organic emissions. This work is of particular relevance to fixed bed and fluidised bed processes where the bed temperature is ca. 1000 'C (or there is a temperature profile through the bed). In these cases particle heating and pyrolysis occurs relatively slowly and interactions between the volatiles can take place. While studying the co-pyrolysis, thermogravimetry, batch pyrolysis and pyroprobe-GC/(MS or FID) were used. In addition, apart from the traditionaltechniques, this study aimed to develop a new technique - heated wire mesh pyrolysis coupled to a GUMS via a probe, which can sample at varying heights from the pyrolysing fuel, and these findings were complemented by the pyrolysis-GC/MS studies of the fuels. These studies suggest that biomass type can lead to a small change of the rate of the coal pyrolysis. Thus, slight synergistic effects were seen for the TGA study, where co-pyrolysed coals in blends often had lower peak temperatures compared to the coal alone, and higher volatile matter yields were produced. Analysis of the gases evolved were consistent with higher gas yields. This effect was present for certain biomass (e. g. oat straw) even after minerals were removed, and so this is not purely the result of catalytic ash components. For combustion studies two techniques were applied. Low heating rate was obtained in a TGA analyser. The high heating rate experiments were performed on pellets exposed to the flame of Meker-type burner. This combustion process was recorded with a high speed frame video recording system. These studies showed that strong synergy can be observed. The TGA combustion revealed the importance of the catalytic elements, particularly potassium, and showed that, ignition of biomass char in the blend aids the ignition of the coal char. As a result, mixtures reach maximum temperatures faster, than seen for the separate fuels. In many cases though, the char burn-out of the blends lasted a similar time to the coals alone. The combustion tests of stationary pellets revealed no pattern for the ignition delay, but exposed strong synergy in volatile combustion, indicating that for pellets of untreated fuel blends the combustion events are dominated by the coal behaviour i. e. the addition of demineralised biomass to the pellet, made it burn in a very similar way to coal alone. The synergy observed in the organic emissions during the combustion of coal and biomass in small appliances is not simply due to interactions of hot volatiles from coal and biomass above the combustion bed. Co-pyrolysis studies suggest that biomass type can lead to a small effect on the rate of the coal pyrolysis, and on the total volatile matter released, but that there are no major changes in the nature of the volatiles. Combustion studies indicate that synergy stronger than seen for pyrolysis tests can be observed, and the coal ignites and burns at lower temperature as a result of the earlier ignition and combustion of the biomass. The overall combustion time is still dominated by the coal char burn-out. Thus, synergy in emission reduction in the co-utilisation of coal and biomass is not simply due to interactions of volatiles in the vapour phase, rather, the processes of pyrolysis and combustion are linked and as such need to be studied together.

In contrast to current coal conversion technology, cooxidative depolymerization of coal is a novel approach to coal liquefaction in that the reactions are carried out under relatively mild conditions. This free radical process utilizes air or oxygen and a suitable co-oxidant (solvent) which acts as a radical and hydrogen transfer agent throughout the coal matrix. Ideally, co-oxidation would lead to the formation of hydroperoxide groups at the reactive bridging sites in the coal matrix, which upon decomposition would lead to C-C bond scission. The effects of several variables on co-oxidation and subsequent post-treatment were investigated. Up to 49% conversion to DMF soluble products was achieved. Further enhancement of solubility is believed to be limited by the failure of hydroperoxide decomposition to lead to C-C bond scission.

The main subject of this Thesis is the production of hard, wear and corrosion resistant cermets tungsten carbide and cobalt cermets (WC-Co) with different contents in cobalt matrix, onto low carbon steels and aluminum alloy Al7075-T6 substrates, by means of Cold Gas Spray (CGS). The current state of the art for the deposition of WC-Co uses High Velocity Oxy-Fuel (HVOF) as the main technique. Understanding both techniques was also one of the keys points in this work. A deep theoretical approach about the CGS process, in which no melting of the particles occurs, was made at first to gain a better comprehension about the behaviour of the powder particles when sprayed onto different substrates and therefore being able to produce good quality coatings. The starting purpose of this doctoral Thesis was to produce WC-25, 17 and 12%Co coatings onto low carbon steel and Al7075-T6 substrates. Until the day, using nitrogen as the process gas, such coatings could not be produced with enough adhesion, thickness and wear and corrosion properties. These are the main characteristics sought by the industry in these coatings. In the end of this doctorate WC-Co coatings were obtained with excellent mechanical and electrochemical properties, adhesion to both low carbon steel and Al7075-T6 substrates. Besides, these properties were increased and improved when compared to the same WC-Co coatings obtained by HVOF conventional deposition technique. Initial problems such as flowability of the powders, bad adherence to the substrate, poor coating quality and extremely low deposition efficiencies were resolved during the period of the Thesis. Also, and taking advantage of the novel coatings and excellent properties obtained using the referred feedstock powders and substrates, the knowledge was transferred to the industry as a trade secret.
En primer lugar, el objetivo principal de este trabajo de investigación fue proporcionar un nuevo método de deposición para depositar cermets de WC-Co. Esta nueva tecnología proporcionó nuevos recubrimientos sin ninguna descomposición de la microestructura del polvo inicial y por lo tanto la mejora de las presentes aplicaciones de WC-Co en la gran industria. La deposición de cermets de WC-Co resistentes al desgaste ha sido siempre una de las principales aplicaciones de las técnicas de proyección térmica convencionales como por ejemplo High Velocity Oxy-Fuel (HVOF). Las demandas de la industria en términos de producción y la necesidad y constante búsqueda de mejores propiedades mecánicas y electroquímicas conducen al objetivo principal y la motivación de esta tesis: la producción de nuevos y mejores recubrimientos de WC-Co sobre varios sustratos utilizando una técnica de deposición nueva, Cold Gas Spraying (CGS). El hecho de que antes de la publicación del primer artículo que nació de este trabajo de investigación no se había depositado previamente con éxito este tipo de materiales por CGS fue también uno de los principales puntos de motivación. Por esta razón, el lector encontrará, en la integridad del documento, los trabajos de investigación que fueron publicados durante estos años de programa de doctorado y cumplen los objetivos principales de esta tesis titulada "Deposición de cermets de WC-Co por Proyección Fría".

Pyrolysis is an attractive alternative for the conversion of solid fuels to valuable chemicals and bio-fuels. In order to obtain more H2 and syngas from pyrolysis of coal and biomass, microwave has been adopted to enhance the co-pyrolysis of coal and biomass, which has been investigated systematically in this study. Firstly, conventional pyrolysis of coal and biomass was carried out using a vertical tube furnace. Characterizations of pyrolytic gas, liquid and solid products were conducted to study the different properties of products from the pyrolysis of coal and biomass. More gas products were produced at higher temperatures and biomass samples produced more H2 and syngas than coals. Bio-oils produced from conventional pyrolysis of biomass samples have relatively simpler compositions compared with those produced from conventional pyrolysis of coals. Char samples produced from conventional pyrolysis of coal and biomass samples show different morphologies due to the different nature of original coal and biomass. Secondly, microwave-induced pyrolysis of coal and biomass was carried out and compared with the results of conventional pyrolysis. Microwave-induced pyrolysis was found to produce pyrolytic gas products with higher contents of H2 and syngas than conventional pyrolysis. The bio-oils produced from microwave-induced pyrolysis were not as complicated as those from conventional pyrolysis. The reason for this is believed to be that both microwave irradiation and the longer residence time favour more complete decomposition of large hydrocarbon molecules in coal and biomass, which subsequently results in less complicated composition compared with bio-oil produced via conventional pyrolysis. Char samples from microwave-induced pyrolysis undergo more complete pyrolysis than char samples from conventional pyrolysis, and results in less volatiles remaining. Because of the thermal annealing process by microwave at the later stage of pyrolysis, char samples produced by microwave-induced pyrolysis have higher peak temperatures and burnout temperatures than those produced by conventional pyrolysis. In char samples prepared via microwave-induced pyrolysis of coal and biomass, special structures are found, such as nano-scale fibers in char samples from gumwood and pine, spheres in char samples from coals as well as coal and biomass blends. Based on the analysis of energy balance, it is evident that microwave-induced pyrolysis is a cost-effective and energy saving method for solid fuel conversion.

Thermal co-processing of coal and biomass has been increasingly focused for its environmental and economic benefits. In the present work, the experimental and kinetic study on co-pyrolysis and co-gasification of Rhenish brown coal (HKN) and wheat straw (WS) was made. The pyrolysis behavior, especially for co-pyrolysis, was investigated in a thermogravimetric analyzer (TGA) and a small fixed bed reactor (LPA). In TGA, the mass loss and reaction rate of single and blend samples were studied under various experimental conditions, and their effects on synergy effects. The synergy effects on products yield and properties of chars were studied in LPA. The kinetics of pyrolysis was obtained based on data from TGA by using the Coats-Redfern method. For gasification with CO2, a small fixed bed reactor (quartz glass reactor), equipped with an online GC to monitor the gas composition, was used. The effects of processing conditions on gasification behavior and synergy effects for mixed chars and co-pyrolysis chars were investigated. The volume reaction model (VRM), shrinking core model (SCM) and random pore model (RPM), were applied to fit the experimental data. The model best fitting the experiments was used to calculate the kinetic parameters. The reaction orders of gasification reactions with single chars are also investigated. The pyrolysis study showed that a small amount of wheat straw added to the brown coal promoted the decomposition better and showed more significant synergy effects. The synergy effects varied with increasing heating rates and pressures, especially at 40 bar. The kinetic parameters were inconsistent with experimental behavior during co-pyrolysis, since the reaction was also affected by heat transfer, contact time, particles distribution and so on. The gasification study on single chars showed that Rhenish brown coal chars had higher reactivity; chars pyrolyzed at higher temperatures showed lower reactivity; and higher gasification temperatures and CO2 partial pressures led to higher reactivity. For co-gasification process, there was no significant synergy effect for mixed chars. However, negative synergy effects (reactivity decreased compared to the calculated values based on rule of mixing) were observed for co-pyrolysis chars, caused by properties change by co-pyrolysis process. For kinetics, the reaction orders of chars ranged from 0.3 to 0.7. Only random pore model fitted most experiments at low and high temperatures. Synergy effects were also observed in kinetic parameters. The values of activation energy E and pre-exponential factor A for mixed chars and co-pyrolysis chars were lower than expected. The negative synergy effects showed the pre-exponential factor A had more effects. However, the higher reactivity of mixed chars than co-pyrolysis chars showed that the reaction was affected more by activation energy E. Therefore, only investigating E or A value was not enough. In addition, a marked compensation effect between activation energies and pre-exponential factors was found in the present study. The isokinetic temperature for the present study was 856 °C. This was close to the temperature at which the gasification reaction transforms from the chemical controlled zone to the diffusion controlled zone for most chars.

Experiments on pulverised coal combustion in air and 02/C02 mixtures of various molar ratios, were conducted in a 20 kW-rated, down-fired furnace equipped with a single pulverised fuel (pt) burner, which was designed for the laboratory-scale experimental studies on coal combustion in air. In coal-02/C02 combustion tests, all the oxidants and fuel were delivered into the furnace with the same configurations as those in the coal-air combustion firing tests. In each test, the coal firing rate was fixed, and the furnace stoichiometric ratio was fixed at SR=1.20. Seven bituminous coals with fuel ratio ranging from 1.50 to 2.33 were used in the study. The effectiveness of air/oxidant staging on reducing NOx emissions was investigated for combustion in air and 02/C02 mixtures. The fate of recycle NO in combustion with different oxidants and combustion conditions was also investigated. Continuous furnace operations with stable flames and a comparable operating temperature to that in air were established for 02/C02 combustion, without major operational problems related to burner ignition, flame stability, coal firing and the effect of oxidants switching, both in unstaged and staged conditions. The results show that temperature and emission profiles are highly influenced by the oxidant compositions. A continuous flame could not be sustained by the direct replacement of combustion air with 02/C02 mixture with the same O2 concentration as air (21 :79-02/C02). In 02/C02 atmospheres, NOx Conversion Ratio (CRNO'..) decreased with the increasing concentration of the CO2 in the oxidant and combustion with 21 :79-02/C02 produced NOx of about one-fourth to that in air. With a same firing rate and combustion stoichiometry. coal combustion in 30:70-02/C02 produced a similar flame temperature profile to that in air combustion.while producing a significantly lower furnace NO, emISSIOn and a higher char burnout. The NO" Conversion ratio (CRNox) ranged from 27.7 - 39.70/0 in air and 18.4 - 35.5% in 30:70-02:C02. The Burnout Efficiency (1180) in air and in 30:70- 02/C02 ranged from 92.5-98.50/0 and 95.0-99.3 % respectively. Compared to that in air combustion, NOx conversion was more sensitive to coal prope11ies in 30:70- 02/C02. The CO concentration in the combustion zone of the 30:70-02/C02 mixture was more than 50% higher than that of air but the Je\'eJ decreased to an insignificant level at the exhaust. With the presence of air in the oxidant from atmospheric leakages, a high CO2 concentration of more than 80% of the flue gas was attained in 30:70-02:C02 combustion, compared to around 15% in air firing. The CO2 concentration in the flue gas could be increased further to more than 90 % by reducing air infiltration into the combustor. The staged combustion tests result show that oxidant staging is a very effective method in reducing NOx emissions for coal combustion in 30:70-02IC02. and can be more effective than in staged air combustion. For coal combustion in air, staging with SR1=0.80 reduced NOx emission by 54 - 650/0, while combustion in 30:70-02/C02. reduced NO" by 44 - 73 %. Compared to normal air combustion, staged combustion in 30:70-02:C02 reduced the overall furnace NOx by 67-77 0/0. The recycled NO tests results show that the NO Reduction Efficiency (l1No) depends on the combustion media. combustion conditions and NO recycling injection locations, and is influenced by the coal properties but not by the recycled NO concentrations. Compared to that in air, NO Reduction Efficiency in 30:70- 02:C02 is more sensiti\'e to coal properties, particularly coal Fuel Ratio (FR).

Co-firing of biomass with coal in fluidized bed combustors is a promising alternative which leads to environmentally friendly use of coal by reducing emissions and provides utilization of biomass residues. Therefore, effect of biomass share on gaseous pollutant emissions from fluidized bed co-firing of various biomass fuels with high calorific value coals have extensively been investigated to date. However, effect of co-firing of olive residue, hazelnut shell and cotton residue with low calorific value lignites having high ash and sulfur contents has not been studied in bubbling fluidized bed combustors to date. In this thesis study, co-firing of typical Turkish lignite with olive residue, hazelnut shell and cotton residue in 0.3 MWt METU Atmospheric Bubbling Fluidized Bed Combustion (ABFBC) Test Rig was investigated in terms of combustion and emission performance and ash behavior of different fuel blends. The results reveal that co-firing of olive residue, hazelnut shell and cotton residue with lignite increases the combustion efficiency and freeboard temperatures compared to those of lignite firing with limestone addition only. O2 and CO2 emissions are not found sensitive to increase in olive residue, hazelnut shell and cotton residue share in fuel blend. Co-firing lowers SO2 emissions considerably while increasing CO emissions. Co-firing of olive residue and hazelnut shell has no significant influence on NO emissions, however, reduces N2O emissions. Co-firing cotton residue results in higher NO and N2O emissions. Regarding to major, minor and trace elements partitioning, co-firing lignite with biomasses under consideration shifts the partitioning of these elements from bottom ash to fly ash. No chlorine is detected in both EDX and XRD analyses of the ash deposits. In conclusion, olive residue, hazelnut shell and cotton residue can easily be co-fired with high ash and sulfur containing lignite without agglomeration and fouling problems.

Fluidization characteristics and co-gasification of pulverized sub-bituminous coal, hybrid poplar wood, corn stover, switchgrass, and their mixtures were investigated. Co-gasification studies were performed over temperature range from 700°C to 900°C in different media (N2, CO2, steam) using a bubbling fluidized bed reactor. In fluidization experiments, pressure drop (ΔP) observed for coal-biomass mixtures was higher than those of single coal and biomass bed materials in the complete fluidization regime. There was no systematic trend observed for minimum fluidization velocity (Umf) with increasing biomass content. However, porosity at minimum fluidization (εmf) increased with increasing biomass content. Channeling effects were observed in biomass bed materials and coal bed with 40 wt.% and 50 wt.% biomass content at low gas flowrates. The effect of coal pressure overshoot reduced with increasing biomass content. Co-gasification of coal and corn stover mixtures showed minor interactions. Synergetic effects were observed with 10 wt.% corn stover. Coal mixed with corn stover formed agglomerates during co-gasification experiments and the effect was severe with increase in corn stover content and at 900°C. Syngas (H2 + CO) concentrations obtained using CO2 as cogasification medium were higher (~78 vol.% at 700°C, ~87 vol.% at 800°C, ~93 vol.% at 900°C) than those obtained with N2 medium (~60 vol.% at 700°C, ~65 vol.% at 800°C, ~75 vol.% at 900°C). Experiments involving co-gasification of coal with poplar showed no synergetic effects. Experimental yields were identical to predicted yield. However, synergetic effects were observed on H2 production when steam was used as the co-gasification medium. Additionally, the presence of steam increased H2/CO ratio up to 2.5 with 10 wt.% hybrid poplar content. Overall, char and tar yields decreased with increasing temperature and increasing biomass content, which led to increase in product gas.

This thesis presents research on the co-gasification characteristic of biomass and coal, and mathematical modelling of the co-gasification process in two main parts: i) experimental investigation and mathematical modelling of reaction kinetics of steam gasification of single char particles of pure coal, pure biomass, and blended coal and biomass; and ii) Experimental investigation and mathematical modelling of gasification characteristics of biomass, coal and their blends in pilot scale gasifiers. From the char reactivity study, the instinct difference in gasification characteristics of the two chars has been explained and reactivity of blended char can be predicted. In the pilot scale gasifier study, effects of blending ratio in feedstock and operating conditions on co-gasification of biomass and coal were investigated.

In this work the combustion characteristics of coal, charcoal, microalgae biomass and blends between these three components were evaluated by means of non-isothermal thermogravimetry. Blends between coal, charcoal and microalgae biomass were made according to the specifications of a D-optimal mixture design so as to be able to model interactions between the three components with maximum precision despite multiple constraints built into the design. These constraints specified that coal can have a minimum value of 70 mass percent in any blend, while microalgae can have a maximum value of 20 mass percent. While coal and charcoal were blended by mixing the two respective dry components, microalgae biomass was incorporated into the blends by first absorbing microalgae onto fine coal from concentrated slurry of the microalgae in water. The microalgae in these blends were therefore intimately associated with the coal. This approach differed substantially from the normal practice of preparing coal – biomass blends (which are usually dry-mixed as for coal – charcoal blends). Proximate analyses of the starting materials showed that the microalgae biomass has a significantly higher volatile matter: fixed carbon content than both coal and charcoal, which should improve the combustion of these materials by providing a more stable combustion flame. Analyses of the thermogravimetric data obtained showed that coal and charcoal have much simpler combustion profiles than microalgae biomass for which five different thermal events could be observed in the DTG combustion profile. Qualitative kinetic analyses showed that the combustion of coal and charcoal follows first-order kinetics, but for microalgae biomass combustion, the first two combustion stages appear to follow first-order kinetics. The TG and DTG profiles for coal, charcoal, microalgae and blends of these three components were used to derive values for the so-called comprehensive combustion property index (S-value), which provides a combined measure of the ease of ignition, rate of combustion, and burn-out temperature. The S-values so obtained were used as response variable for the construction of a response surface model in the experimental domain investigated. Following statistical validation of the response surface model, the model was used to predict an optimum S-value or a blend that would display optimum combustion behaviour. Two optimum blends were obtained from the optimisation process, one in which only charcoal is added to coal, and one in which only microalgae is added to coal. Adding both charcoal and microalgae produced an antagonistic effect compared to when only one of these are used. Qualitative kinetic analyses of the combustion data of blends indicate that blends of coal and charcoal combust in a manner similar to the individual components (hence following first-order kinetics), but blends of coal and microalgae follow more complex kinetics despite the fact that the combustion profile is visibly more simple compared to the combustion profile for microalgae alone.

The co-firing technology of coal with biomass has been implemented to enhance the usage of biomass in power generation, thus reducing the release of greenhouse gas emissions. This study deals with the fireside issues, namely ash-related issues that arise during co-combustion of coal and biomass takes place. Ash release from biomass can lead to ash deposition problems such as fouling and slagging on surfacesof power generation boilers. The scope of this work includes the development of a conceptual model that predicts the ash release behaviour and chemical composition of inorganics in coal and biomass when combusted. An advanced analytical method was developed and introduced in this work to determine the speciation of biomass.The method known as pH extraction analysis was used to determine the inorganic speciation in three biomass samples, namely wood chips, wood bark and straw. The speciation of biomass and coal was used as an input to the model to predict the behaviour and release of ash. It was found that the main gas phases during the combustion of biomass are KCl, NaCl, K2SO4 and Na2SO4. Gas-to-particle formation calculations were carried out to determine the chemical composition of coal andbiomass when cooling takes place in the boiler. The results obtained in this work can be used in future work to determine the ash deposition of coal and biomass in boilers.

Thesis (M.S.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains vi, 184 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 82-84).

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005.
"Sponsored by: CLP Research Institute." "HKUST project no.: CLPRI02/03.EG01." Includes bibliographical references (leaves 76-83). Also available in electronic version.

As a carbon neutral and renewable source of energy, biomass carries a high potential to help sustain the future energy demand. The co-firing of coal and biomass mixtures is an alternative fuel route for the existing coal based reactors. The main challenges associated with co-firing involves proper understanding of the co-firing behavior of blended coal-biomass fuels, and proper understanding of advanced gasification systems used for converting such blended fuels to energy. The pyrolysis and combustion behavior of coal-biomass mixtures was quantified by devising laboratory experiments and mathematical models. The pyrolysis-combustion behavior of blended fuels was quantified on the basis of their physicochemical, kinetic, energetic and evolved gas behavior during pyrolysis/combustion. The energetic behavior of fuels was quantified by applying mathematical models onto the experimental data to obtain heat of pyrolysis and heat of combustion. Fuel performance models were developed to compare the pyrolysis and combustion performance of non-blended and blended fuels. The effect of blended fuel briquetting was also analyzed to find solutions related to coal and biomass co-firing by developing a bench scale fuel combustion setup. The collected data was analyzed to identify the effects of fuel blending and briquetting on fuel combustion performance, ignitability, flammability and evolved pollutant gases. A further effort was made in this research to develop the understanding of fluidized bed hydrodynamics. A lab scale cold-flow fluidized bed setup was developed and novel non-intrusive techniques were applied to quantify the hydrodynamics behavior. Particle Image Velocimetry and Digital Image Analysis algorithms were used to investigate the evolution of multiple inlet gas jets located at its distributor base. Results were used to develop a comprehensive grid-zone phenomenological model and determine hydrodynamics parameters such as jet particle entrainment velocities and void fraction among others. The results were further used to study the effect of fluidization velocity, particle diameter, particle density, distributor orifice diameter and orifice pitch on the solid circulation in fluidized beds.
Ph. D.

Stricter greenhouse gas emission limits and renewable energy requirements are expected to further increase the worldwide practices of firing biomass and co-firing biomass with coal, which are both considered more sustainable energy sources than coal-only combustion. Reuse options for the by-products of these processes -biomass ash and co-fired fly ash -remain limited. Therefore, this research examines their use as supplementary cementitious materials (SCMs) in concrete and as precursors for alkali-activated geopolymers. Toward their potential use as an SCM, after characterizing these ashes assessing their compliance with ASTM C618 requirements, their impact on early-age hydration kinetics, rheology, setting time and permeability was assessed. Furthermore, the pozzolanic reactivity and the microstructural and hydrated phase development of the cement-ash samples were analyzed. The results show that a wood biomass ash sample was not satisfactory for use as an SCM. On the other hand, the findings demonstrate that co-fired fly ashes can significantly improve the strength and durability properties of concrete compared to ordinary portland cement, in part due to their pozzolanicity. Thus, it is recommended that the ASTM C618 standard be modified to permit co-fired fly ash sources that meet existing requirements and any additional requirements deemed necessary to ensure their satisfactory performance when used in concrete. Toward their potential use in geopolymers, this study characterized the early-age reaction kinetics and rheological behavior of these materials, showing that their exothermic reactivity, plastic viscosity and yield stress are significantly influenced by the activator solution chemistry and other characteristics of the ash. Two co-fired fly ashes were successfully polymerized, with compressive strengths generally highest for ashes activated with solutions with a molar ratio of SiO₂/(Na₂O + K₂O) = 1. The results show that geopolymerization is a viable beneficial reuse for these emerging by-products. Further characterization of these materials by scanning transmission X-ray microscopy analysis revealed the heterogeneity of the aluminosilicate phase composition of the co-fired fly ash geopolymer gel at the nano- to micro-scale.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 129-133).
Oxy-coal combustion technology has great potential as one of the major CO2 capture technologies for power generation from coal. The distinguishing feature of oxy-coal combustion is that the oxygen source is a high concentration oxygen stream and the product flue gas consists primarily of CO₂ and H₂0 with contaminants like NOx, SOx, and non-condensable gases like argon, oxygen and nitrogen. For carbon sequestration and Enhanced Oil Recovery (EOR) applications, pipeline transport standards as well as storage specifications impose concentration limits on these contaminants. These must be removed to ensure that the transported CO₂-rich stream stays within specified limits to prevent aqueous phase separation, hydrate formation, and corrosion due to acids, water or oxygen. The purification process however constitutes additional energy consumption and lowers overall cycle efficiency. Purification options like traditional flue gas desulfurization (FGD), selective catalytic reduction (SCR), catalytic O₂ consumption, packed bed adsorption and low temperature flash separation have been proposed. In this thesis, we develop a novel CO2 purification process model for oxy combustion systems that utilizes high-pressure reactive absorption columns for NOx and SOxrem oval and distillation strategies for noncondensable gas removal. This process results in significant cost savings and lower energy consumption compared to the traditional systems. We conduct a sensitivity analysis NOx and SOx removal system to determine the key performance parameters and based on the results present a modification to the base case that results in further cost and energy savings. Different strategies for the removal of non-condensable gases are developed and compared. This study also explores opportunities for integrating the CO₂ purification unit (CPU) with the base cycle and the impacts of the different strategies on the overall oxy combustion cycle efficiency are presented. A cost analysis for the proposed purification process is also presented.
by Chukwunwike Ogbonnia Iloeje.
S.M.

In Escherichia coli, replication initiates when the DnaA-ATP protein assembles at the origin oriC. Hda protein in complex with the beta sliding clamp protein (? clamp) on DNA, functions in altering the nucleotide bound form of the replication initiator DnaA protein from DnaA-ATP to DnaA-ADP in a process termed as Regulatory Inactivation of DnaA (RIDA). DnaA also functions as a transcription factor of several genes including the aerobic ribonucleotide reductase nrdAB genes. In this study, I have exploited the cold sensitive growth phenotype due to loss of Hda function and its suppressors to understand the Hda function beyond initiation of replication. I describe the global transcriptional changes in strains lacking Hda and suppressed by two different modes. Loss of Hda function results in reduced expression of nrdAB genes, altered thiol status of the cell, SOS induction and increase in iron import due to de-repression of the Fur regulon. Strains lacking Hda function have increased requirement for the RpoH mediated heat shock response that affects the activity of NrdAB. I have shown that oversupply of ? clamp results in a slow growth phenotype which is more pronounced at low temperatures. Six mutant ? clamps suppress this slow growth phenotype. One of the mutant clamp that has the E202K mutation displays a hyper-Hda phenotypes such as hydroxyurea resistance and increase in nrdAB expression. These phenotypes were dependent on Hda but independent of SOS response. Finally, the slow growth phenotype due to overexpression of ? clamp can be compensated by co-overproducing Hda. This leads to a model where ? clamp could recruit Hda as a response to replication defects independent of SOS response.

The waste products acid mine drainage formed during coal mining and fly ash from coal burning power generation, pose substantial environmental and economic problems for South Africa. Eskom has developed a remediation system employing alkaline fly ash to neutralize and precipitate heavy metals from toxic acidic acid mine drainage streams. The aim of this study was to assess the microbial diversity in and microbial impact on this remediation system.

The objective of this thesis is to experimentally investigate the performance of steam gasification of chars of pure coal (lignite, sub-bituminous), pure biomass (radiata pine, eucalyptus nitens) and their blends. The influences of gasification temperature, types of coal and biomass, coal-biomass blending ratio, alkali and alkaline earth metal (AAEM) in lignite, on specific gasification characteristics (producer gas composition and yield, char reactivity) were studied. In addition, synergistic effects in co-gasification of coal-biomass blend char were also investigated. This project is in accordance with objectives of the BISGAS Consortium. In this study, experiments were performed in a bench-scale gasifier at gasification temperatures of 850°C, 900°C and 950°C, respectively. Two types of coals (lignite and sub-bituminous) and two kinds of biomass (radiata pine and eucalyptus nitens) from New Zealand were selected as sample fuels. From these raw materials, the chars with coal-to-biomass blending ratios of 0:100 (pure coal), 20:80, 50:50, 80:20 and 100:0 (pure biomass), which were derived through the devolatilization at temperature of 900°C for 7 minutes, were gasified with steam as gasification agent. During the gasification tests, the producer gas composition and gas production were continuously analysed using a Micro gas chromatograph. When the gas production was undetectable, the gasification process was assumed to be completed and the gasification time was recorded. The gasification producer gas consisted of three main gas components: hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2). The results from gasification of chars of individual solid fuels (coal or biomass) confirmed that biomass char gasification was faster than coal char gasification. The influences of gasification temperatures were shown as: when gasification temperature increased, the H2 yield increased in coal char gasification but decreased in biomass char gasification. In the meantime, CO yields increased while CO2 yields decreased in both coal char and biomass char gasification. In addition, the char reactivity of all the pure fuel samples increased with elevated gasification temperatures. The results from co-gasification of coal-biomass blend char exhibited that the syngas production rate, which is defined as the total gas production divided by the gasification completion time, was enhanced by an increase in gasification temperatures as well as an increase in the biomass proportion in the blend. The AAEM species played a significant catalytic role in both gasification of pure coal chars and co-gasification of coal-biomass blend chars. The presence of AAEM increased the producer gas yield and enhanced the char reactivity. The positive synergistic effects of the coal-biomass blending char on syngas production rate only existed in the co-gasification of lignite-eucalyptus nitens blend chars. The other blend chars showed either insignificant synergistic effects or negative effects on the syngas production rate.

Thesis (PhD)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Gasification provides a proven alternative to the dependence on petroleum for the production of high value products such as liquid fuels and chemicals. Syngas, the main product from gasification can be converted to fuels and chemicals via a number of possible synthesis processes. Coal and natural gas are currently the main feedstock used for syngas production. In South Africa (SA), Sasol operates the largest commercial coal-to-liquids conversion process in the world, based on updraft fixed bed gasification of low grade coal to syngas. Co-utilizing alternative and more sustainable feedstock (such as biomass and wastes) with coal in existing coal-based plants offers a realistic approach to reducing the costs and risks associated with setting up dedicated biomass conversion plants. An experimental and modelling investigation was performed to assess the impacts of co-gasifying two of the most commonly available agricultural wastes in SA (sugarcane bagasse and corn residue) with typical low grade SA coals, on the main products of updraft fixed bed gasification, i.e. liquid condensates and syngas. Condensates are produced in the pyrolysis section of the updraft gasifier, whereas syngas is a result of residual char conversion. An experimental set-up that simulates the pyrolysis section of the gasifier was employed to investigate the yield and composition of devolatilized products at industrially relevant conditions of 26 bars and 400-600°C. The results show that about 15 wt% of coal and 70 wt% of biomass are devolatilized during the pyrolysis process. The biomass derived condensates were determined to comprise of significantly higher quantities of oxygenates such as organic acids, phenols, ketones, and alcohols, whereas coal derived hydrocarbon condensates were dominated by polycyclic aromatic hydrocarbons, creosotes and phenols. Results of investigation into the influence of coal-biomass feedstock mix ratio on yields of products from pyrolysis show limited evidence of non-additive or synergistic behaviour on the overall distribution of solid, liquid and gas yields. On the other hand, in terms of the distribution of specific liquid phase hydrocarbons, there was significant evidence in favour of non-additive pyrolysis behaviour, as indicated by the non-additive yield distribution of specific chemicals. Synergistic trends could also be observed in the thermogravimetric (TGA) study of pyrolysis under kinetically controlled non-isothermal conditions. Model free and model fitting kinetic analysis of the TGA data revealed activation energies ranging between 94-212 kJ mol-1 for the biomass fuels and 147-377 kJ mol-1 for coal. Synergistic interactions may be linked to the increased presence of hydrogen in biomass fuels which partially saturates free radicals formed during earlier stages of devolatilization, thereby preventing secondary recombination reactions that would have produced chars, allowing for the increased formation of volatile species instead. Analysis of char obtained from the co-pyrolysis experiments revealed that the fixed carbon and volatile content of the blended chars is is proportional to the percentage of biomass and coal in the mixture. CO2 reactivity experiments on the chars showed that the addition of biomass to coal did not impose any kinetic limitation on the gasification of blended chars. The blended chars decomposed at approximately the same rate as when coal was gasified alone, even at higher biomass concentrations in the original feedstock blend. Based on these observations, a semi-empirical equilibrium based simulation of syngas production for co-gasification of coalbiomass blends at various mix ratios was developed using ASPEN Plus. The model showed that H2/CO ratio was relatively unaffected by biomass addition to the coal fuel mix, whereas syngas heating value and thermal efficiency were negatively affected. Subsequent evaluation of the production cost of syngas at biomass inputs ranging between 0-20 wt% of coal reflected the significant additional cost of pretreating biomass (3.3% of total capital investment). This resulted in co-gasification derived syngas production costs of ZAR146/tonne (ZAR12.6/GJ) at 80:20 coalbiomass feedstock ratio, compared to a baseline (coal only) cost of ZAR130/tonne (ZAR10.7/GJ). Sensitivity analysis that varied biomass costs from ZAR0 ZAR470 revealed that syngas production costs from co-gasification remained significantly higher than baseline costs, even at low to zero prices of the biomass feedstock. This remained the case even after taking account of a carbon tax of up to ZAR117/tCO2. However, for range of carbon tax values suggested by the SA treasury (ZAR70 tCO2 to ZAR200 tCO2), the avoided carbon tax due to co-feeding biomass can offset between 40-96% of the specific retrofitting cost at 80:20 coal-biomass feedstock mass ratio. In summary, this dissertation has showed that in addition to the widely recognized problems of ash fouling and sintering, co-feeding of biomass in existing coal based updraft gasification plants poses some challenges in terms of impacts on condensates and syngas quality, and production costs. Further research is required to investigate the potential in ameliorating some of these impacts by developing new high value product streams (such as acetic acid) from the significant fraction of condensates derived from biomass.
AFRIKAANSE OPSOMMING: Vergassing bied 'n beproefde alternatief vir die afhanklikheid van petroleum vir die produksie van hoë waarde produkte soos vloeibare brandstof en chemikalieë. Sintese gas, die belangrikste produk van vergassing, kan omgeskakel word na brandstof en chemikalieë deur 'n aantal moontlike sintese prosesse. Steenkool en aardgas is tans die belangrikste grondstowwe wat gebruik word vir sintese gas produksie. In Suid-Afrika (SA) bedryf Sasol die grootste kommersiële steenkool-totvloeistof omskakelingsproses in die wêreld, gebaseer op stygstroom vastebed vergassing van laegraadse steenkool na sintese gas. Die gebruik van alternatiewe en meer volhoubare grondstowwe (soos biomassa en afval) saam met steenkool in die bestaande steenkool-gebaseerde aanlegte bied 'n realistiese benadering tot die vermindering van die koste en risiko's wat verband hou met die oprigting van toegewyde biomassa omskakelingsaanlegte. 'n Eksperimentele en modelleringsondersoek is uitgevoer om die impak van gesamentlike vergassing van twee van die mees algemeen beskikbare landbouafvalprodukte in Suid-Afrika (suikerriet bagasse en mieliereste) met tipiese laegraadse SA steenkool op die vernaamste produkte van stygstroom vastebed vergassing, dws vloeistof kondensate en sintese gas, te evalueer. Kondensate word geproduseer in die piroliese gedeelte van die stygstroomvergasser, terwyl sintese gas 'n resultaat is van die omskakeling van oorblywende houtskool. 'n Eksperimentele opstelling wat die piroliese gedeelte van die vergasser simuleer is gebruik om die opbrengs en die samestelling van produkte waarvan die vlugtige komponente verwyder is by industrie relevante toestande van 26 bar en 400-600°C te ondersoek. Die resultate toon dat ongeveer 15% (massabasis) van die steenkool en 70% (massabasis) van die biomassa verlore gaan aan vlugtige komponente tydens die piroliese proses. Daar is vasgestel dat die kondensate afkomstig van biomassa uit aansienlik hoër hoeveelhede suurstofryke verbindings soos organiese sure, fenole, ketone, en alkohole bestaan, terwyl koolwaterstofkondensate afkomstig uit steenkool oorwegend bectaan uit polisikliese aromatise verbindings, kreosote en fenole. Die resultate van die ondersoek na die invloed van die verhouding van steenkool tot biomassa grondstof op piroliese opbrengste toon beperkte bewyse van nie-toevoegende of sinergistiese gedrag op die algehele verspreiding van soliede, vloeistof en gas opbrengste. Aan die ander kant, in terme van die verspreiding van spesifieke vloeibare fase koolwaterstowwe, was daar beduidende bewyse ten gunste van 'n sinergistiese piroliese gedrag. Sinergistiese tendense is ook waargeneem in die termogravimetriese (TGA) studie van piroliese onder kineties beheerde nieisotermiese toestande. Modelvrye en modelpassende kinetiese analise van die TGA data het aan die lig gebring dat aktiveringsenergieë wissel tussen 94-212 kJ mol-1 vir biomassa brandstof en 147-377 kJ mol-1 vir steenkool. Ontleding van die houtskool verkry uit die gesamentlike piroliese eksperimente het aan die lig gebring dat die onmiddellike kenmerke van die gemengde houtskool die geweegde gemiddelde van die individuele waardes vir steenkool en biomassa benader. CO2 reaktiwiteitseksperimente op die houtskool het getoon dat die byvoeging van biomassa by steenkool nie enige kinetiese beperking op die vergassing van gemengde houtskool plaas nie. Die gemengde houtskool ontbind teen ongeveer dieselfde tempo as wanneer steenkool alleen vergas is, selfs teen hoër biomassa konsentrasies in die oorspronklike grondstofmengsel. Op grond van hierdie waarnemings is 'n semi-empiriese ewewig-gebaseerde simulasie van sintese gas produksie vir gesamentlike vergassing van steenkool-biomassa-mengsels vir verskeie mengverhoudings ontwikkel met behulp van Aspen Plus. Die model het getoon dat die H2/CO verhouding relatief min geraak is deur biomassa by die steenkool brandstofmengsel te voeg, terwyl sintese gas se verhittingswaarde en termiese doeltreffendheid negatief geraak is. Daaropvolgende evaluering van die produksiekoste van sintese gas vir biomassa insette wat wissel tussen 0-20% (massabasis) van die hoeveelheid steenkool het die aansienlike addisionele koste van die vooraf behandeling van biomassa (3.3% van die totale kapitale belegging) gereflekteer. Dit het gelei tot 'n produksiekoste van ZAR146/ton (ZAR12.6/GJ) vir sintese gas afkomstig uit gesamentlike-vergassing van 'n 80:20 steebkool-biomassa grondstof mengesl, in vergelyking met 'n basislyn (steenkool) koste van ZAR130/ton (ZAR10.7/GJ). Sensitiwiteitsanalise wat biomassa koste van ZAR0 - ZAR470 gevarieër het, het aan die lig gebring dat sintese gas produksiekoste van gesamentlike vergassing aansienlik hoër bly as die basislyn koste, selfs teen 'n lae of nul prys van biomassa grondstof. Dit bly die geval selfs nadat koolstof belasting van tot ZAR117/tCO2 in ag geneem is. In opsomming het hierdie verhandeling getoon dat, bykomend tot die wyd-erkende probleme van as besoedeling en sintering, die gesamentlike gebruik van biomassa in bestaande steenkool stygstroom vergassingsaanlegte groot uitdagings inhou in terme van die impak op die kwaliteit van kondensate en sintese gas, asook produksiekoste. Verdere navorsing is nodig om die potensiaal te ondersoek vir die verbetering van sommige van hierdie impakte deur die ontwikkeling van nuwe hoë waarde produkstrome (soos asynsuur) uit die beduidende breukdeel van kondensate wat verkry word uit biomassa.

In this thesis, a model that couples a reduced alkali kinetic mechanism for alkali sulphate formation during biomass combustion with an ash deposition model using computational fluid dynamics (CFD) techniques has been presented. Starting with a detailed gas-phase kinetic mechanism for the alkali chemistry, a systematic reduction procedure has been performed using a sensitivity analysis to reduce the reaction mechanism to a level that can be implemented into a CFD calculation. An ash deposition model that takes into consideration the ash-sticking probability and the condensation of potassium salts has been developed. The reduced mechanism and the deposition model developed are implemented into a CFD model to predict ash depositions in a 10 MWth biomass grate furnace. Also, a CFD model to predict the deposition rates for the co-combustion of coal with biomass has been developed. This deposition model is based on the combined sticking probabilities of the ash particle viscosity and the melting behaviour of the ash particles. A Numerical Slagging Index (NSI) is also employed to estimate the degree of the sintering of the deposits. Experimental data from the Entrained Flow Reactor (EFR) at Imperial College, London, have been used to validate the models. The predicted results from both the ash deposition models agreed with the experimental measurements, and the NSI has successfully ranked the investigated coal-biomass mixtures according to their degree of sintering.

Co-combustion of biomass with coal has been investigated in a 0.15 m diameter and 2.3 m high fluidised bed combustor under various fluidisation and operating conditions. Biomass materials investigated were chicken waste, rice husk, palm kernel shells and fibres, refuse derived fuel and wood wastes. These were selected because they are produced in large quantities particularly in the Far East. The carbon combustion efficiency was profoundly influenced by the operating and fluidising parameters in the decreased following order: fuel properties (particle size and density), coal mass fraction, fluidising velocity, excess air and bed temperature. The smaller particle size and lower particle density of the fuels (i.e. coal/chicken waste, coal/rice husk and coal/wood powder), the higher carbon combustion efficiency obtained in the range of 86-90%, 83-88%, 87-92%, respectively. The carbon combustion efficiency increases in the range of 3% to 20% as the coal fraction increased from 0% to 70%, under various fluidisation and operating conditions. Also, the carbon combustion efficiency increases with increasing excess air from 30- 50% in the range of 5 - 12 % at 50% coal mass fraction in the biomass mixture. However, further increased of excess air to 70% will reduced the carbon combustion efficiency. Relatively, increasing fluidising velocity contributed to a greater particle elutriation rate than the carbon to CO conversion rate and hence increased the unburned carbon. Furthermore, the bed temperature had insignificant influence of carbon combustion efficiency among the biomass fuels. Depending upon excess air ranges, fluctuations of CO emissions between 200 - 1500 ppm were observed when coal added to almost all biomass mixtures. In ash analyses, the percentages of unburned carbon were found to have increased in the range 3 to 30% of the ash content with the increases of coal fraction in the coal! biomass mixture. Furthermore, no fouling, ash deposition and bed agglomeration was observed during the combustion runs for all tests due to lower operating bed temperature applied. Lastly, a simple model was developed to predict the amount of combustion in the freeboard. This study demonstrated the capability of co-firing biomass with coal and also demonstrated the capability to be burnt efficiently in existing coal-fired boilers with minimum modification.

Ce travail vise à estimer l’impact de co-infections sur le terrain et à mieux comprendre le synergisme possible entre agents pathogènes en conditions expérimentales. Nous nous sommes intéressés à E. coli (O78) et au virus influenza faiblement pathogène (LPAIV, H6N1) dans le modèle dinde. Les oiseaux ont été infectés par voie aérosole pour reproduire l’infection respiratoire. L’excrétion virale ainsi que les lésions ont été plus importantes lors de la co-infection, ce qui suggère une patho-génicité accrue. Ces résultats montrent que E. coli et LPAIV ont un effet additif sur la maladie respiratoire lors qu’ils ont été inoculés soit simultanément soit en différé (à 3 jours d’intervalle) à des dindes naïves. En parallèle, nous avons étudié les virus respiratoires en circulation dans les élevages pakistanais. Des co-infections avec le LPAIV H9 (lignage G1) et le virus de la maladie de Newcastle (génotype VII) ont été fréquemment observées
The purpose of this study was to assess the burden of co-infections in the field and to better understand the possible synergism between pathogens in a laboratory setting. We focussed on E. coli (O78) and low pathogenic avian influenza virus (LPAIV, H6N1) in turkey model and infected the birds via the aerosol route to reproduce respiratory disease. Viral shedding and lesions were more severe and persisted longer during coinfection indicating possible enhancement of pathogenesis for LPAIV by E. coli and vice versa. These findings all endorse our conclusions that E. coli and LPAIV exercise an additive pathogenic effect in the reproduction of respiratory disease if given simultaneously or spaced by three days between the viral and the bacterial challenges to susceptible turkeys. In parallel, we studied avian respiratory agents circulating in the field in Pakistani farms. There, we focussed on co-infections as well, targeting viruses only as a first study. We observed frequent LPAIV H9 (G1 lineage) and Newcastle disease virus (genotype VII) coinfections in the field

Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2006.
"May, 2006." Title from electronic dissertation title page (viewed 10/11/2006) Advisor, James L. White; Committee members, Avraam I. Isayev, Thein Kyu, Darrell H. Reneker, Shing-Chung "Josh" Wong; Department Chair, Sadhan C. Jana; Dean of the College, Frank N. Kelley; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

With the limited reserves of fossil fuels and the environmental problems associated with their use, the world is moving towards cleaner, renewable, and sustainable sources of energy. Biomass is a promising feedstock towards attaining this goal because it is abundant, renewable, and can be considered as a carbon neutral source of energy. Syngas can be further processed to produce liquid fuels, hydrogen, high value chemicals, or it can be converted to heat and power using turbines. Most of the downstream processing of syngas occurs at high pressures, which requires cost intensive gas compression. It has been considered to be techno-economically advantageous to generate pressurized syngas by performing high-pressure gasification. Gasification utilizes high temperatures and an oxidizing gas to convert biomass to synthesis gas (syngas, a mixture of CO and H2). Most of the past studies on gasification used process conditions that did not simulate an industrial gasification operation. This work aims at understanding the chemical and physical transformations taking place during high-pressure biomass gasification at heating rates of practical significance. We have adopted an approach of breaking down the gasification process into two steps: 1) Pyrolysis or devolatalization (fast step), and 2) Char gasification (slow step). This approach allows us to understand pyrolysis and char gasification separately and also to study the effect of pyrolysis conditions on the char gasification kinetics. Alkali and alkaline earth metals in biomass are known to catalyze the gasification reaction. This potentially makes biomass feedstock a cheap source of catalyst during coal gasification. This work also explores catalytic interactions in biomass-coal blends during co-gasification of the mixed feeds. The results of this study can be divided into four parts: (a) pyrolysis of loblolly pine; (b) gasification of pine chars; (c) pyrolysis and gasification of switchgrass; (d) co-gasification of pine/switchgrass with lignite and bituminous coals.

In this study, combustion performances and emission characteristics of olive cake and olive cake+coal mixture are investigated in a bubbling fluidized bed of 102 mm inside diameter and 900 mm height. The average particle sizes of coal and olive cake used in the experiments were 1.57 mm and 1.52 mm, respectively. Flue gas concentrations of O2, CO, SO2, NOx, and total hydrocarbons (CmHn) were measured during combustion experiments. Operational parameters (excess air ratio, secondary air injection) were changed and variation of pollutant concentrations and combustion efficiency with these operational parameters were studied. The temperature profiles measured along the combustor column was found higher in the freeboard for olive cake than coal due to combustion of hydrocarbons mostly in the freeboard. The location of the maximum temperature in the freeboard shifted to the upper part of the column, as the volatile matter content in the fuel mixture increased. Combustion efficiencies in the range of 83.6-90.1% were obtained for olive cake with the excess air ratio of 1.12-2.30. The corresponding combustion efficiency for coal was 98.4-99.7% under the same conditions. As the CO and hydrocarbon concentration in the flue gas increased, the combustion efficiency decreased. Also co-combustion experiments of olive cake and coal for various mixing ratios were carried out. As the amount of olive cake in the fuel mixture increased, SO2 emissions decreased because of the very low sulfur content of olive cake. In order to increase the combustion efficiency, secondary air was injected into the freeboard which was a good solution to decrease the CO and hydrocarbon emissions, and to increase the combustion efficiency. For the setup used in this study, the optimum operating conditions with respect to NOx and SO2 emissions were found as 1.35 for excess air ratio, and 30 L/min for secondary air flowrate for the combustion of 75 wt% olive cake and 25 wt% coal mixture. Highest combustion efficiency of 99.8% was obtained with an excess air ratio of 1.7, secondary air flow rate of 40 L/min for the combustion of 25 wt% olive cake and 75 wt% coal mixture.

This master thesis describes the co-firing concept, benefits and opportunities of pretreated biomass in pulverized coal boilers for industrial use. Burning fossil fuels, i.e. coal is under immense political pressure as European Union (EU) and other countries are trying to bring down the CO2 emission. Biomass combustion is already a proven technology and it plays a greater role in reducing CO2 emission. The main objective of this thesis is the brief study of computational fluid dynamics (CFD) modelling to examine the co-firing of greater amount of pretreated biomass and pulverized coal in a 200MWe pulverized coal boiler. Here, we exchange around 50 % of existing fuel in pulverized coal boiler with torrefied biomass. Torrefied biomass aids to increase the efficiency of existing coal boiler and cut down the CO2 emission. In this work, two cases of co-firing of pretreated biomass and coal have been investigated by CFD. Firstly, an experimental work was done in a laboratory scale to have few different types of torrefied biomass with different degrees of torrefaction. The devolatilization kinetics and char oxidation kinetics were also determined by experiments and other parameters have been calculated. One important aspect of this work has been to evaluate the performance of torrefaction based co-firing. Therefore, co-firing case has been compared to the 100 % coal feed case to understand the performance of torrefaction based co-firing. Furthermore, fluid flow, particles trajectories, heat transfer, and different emission behaviors have been studied. In addition, mechanisms of corrosion during co-firing have been studied and a guideline has been provided for corrosion model for analyzing the characteristics of alkali metals and their effects in co-firing coal boiler. The outcome from the CFD simulation indicated that boiler efficiency increases and the net CO2 emission reduced with increasing the biomass percentage in the co-firing system.

Most of the energy produced in the world comes from fossil fuels: coal, oil and gas. Amongst them, coal is the most abundant and widespread fossil fuel in the world. Underground Coal Gasi cation (UCG), an in situ method to extract the calori c value of the coal, has been known for a century but has had very limited implementation throughout the world, mainly due to the availability of cheap oil over that period. It is now gaining relevance in order to unlock vast resources of coal currently not exploitable by conventional mining. However, growing concern on increased levels of carbon dioxide concentration in the atmosphere is pointing out the necessity to reduce the use of fossil fuels. Since alternative sources of energy (e.g. nuclear and renewables) are not in a position to meet the constantly increasing demand in a short term, carbon capture and its geological sequestration (CCS) is considered the best remedial option. An environmental risk assessment framework has been developed for coupling UCG to CCS accounting for bene ts and cost from both global and local perspectives. A UCG site presents signi cant di erences from other typical CCS projected scenarios, most notably the injection of CO2 into a heavily fractured zone. A model which accounts for ow in fractures represented by dual-porosity ow (TOUGH2) is coupled to a geomechanical model (FLAC3D). The impact of this fractured zone in the CO2 injection pressure buildup and stress eld is evaluated. Furthermore the effect of stress-dependent fracture permeability is assessed with the hydro-mechanically i coupled compositional simulator GEM. Simulation results suggest that in such a scenario, CO2 injectivity and dissolution improve though con nement is compromised and commercial injection rates seem unattainable. The e ects of miscibility and relative permeability on pressure buildup implemented in semianalytical solutions are also evaluated. Albeit further research is required, a UCG operation may, therefore, not be able to accommodate the produced CO2 in the gasi ed cavity and its surroundings in a safe and economical fashion. Rigorous studies and management practices are needed to establish the requirements for secure long-term con nement of the carbon dioxide in such scenario.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Nesta dissertação, investiga-se através da análise termogravimétrica o comportamento da combustão de amostras de carvão mineral, bagaço de cana-de-açúcar, bagaço de sorgo biomassa e das misturas de carvão-biomassa. A biomassa e o carvão possuem propriedades físico-químicas diferentes que proporcionam comportamento térmico diferente durante o processo de co-combustão, desta forma o objetivo desta pesquisa é caracterizar o comportamento térmico de misturas de carvão mineral com bagaço de cana-de-açúcar e bagaço de sorgo em atmosferas simuladas de combustão (O2/N2) e oxicombustão (O2/CO2). Os experimentos foram realizados em duplicata em um analisador termogravimétrico utilizando uma razão de aquecimento de 10 °C/min. Foi considerada uma granulometria uniforme para todos os materiais (63 µm) com a finalidade de garantir uma mistura homogênea. Foram estudadas quatro proporções de biomassa na mistura (10, 25, 50 e 75%). A partir das técnicas de termogravimetria (TG) e termogravimetria derivada (DTG) foram determinados parâmetros tais como Índice de combustão, sinergismo e energia de ativação, bem como avaliada a influência da atmosfera de combustão sobre esses parâmetros. Os resultados indicam que o bagaço de cana-de-açúcar apresenta valor de energia de ativação inferior ao registrado para o bagaço de sorgo e desempenho de combustão superior ao do bagaço de sorgo. Para as misturas, os melhores resultados foram registrados até a proporção de 25% de biomassa na mistura. Avaliando individualmente cada material, quando se substitui o N2 por CO2 pode-se observar um aumento na reatividade da reação, uma maior oxidação dos materiais e uma melhora nos parâmetros avaliados. Para ambas as misturas não foram observadas mudanças significativas no perfil de combustão quando o N2 é substituído por CO2. No entanto, a presença da biomassa na co-combustão com o carvão, além dos benefícios econômicos e ambientais, aumentou o desempenho da combustão do carvão mineral em ambas as atmosferas.
This dissertation investigates by thermogravimetric analysis the behavior of the combustion of coal, sugarcane bagasse, sorghum biomass bagasse and coal-biomass blends. The biomass and coal have different physicochemical properties that provide different thermal behavior during the process of co-combustion, thus the aim of this research is to characterize the thermal behavior of coal mixed with sugarcane bagasse and sorghum bagasse in simulated atmospheres of combustion (O2/N2) and oxycombustion (O2/CO2). The experiments were performed in duplicate in a thermogravimetric analyzer using a heating rate of 10 ° C/min. A uniform particle size for all materials (63 μm) in order to ensure a homogeneous mixture was considered. Four biomass ratios were studied in the blend (10, 25, 50 and 75%). From the techniques of Thermogravimetry (TG) and Derivative Thermogravimetry (DTG) curves were determined parameters such as: Combustion index, synergism and activation energy and evaluated the influence of combustion atmosphere on these parameters. The results indicate that the sugarcane bagasse presents a lower activation energy value than sorghum bagasse and combustion performance higher than sorghum bagasse. For mixtures, best results were recorded up to 25% proportion of biomass in the blend. Individually evaluating each material, when replacing N2 by CO2 can be seen an increase in the reactivity of the reaction, the increased oxidation of the materials and an improvement in the evaluated parameters. For both blends, no significant changes in combustion profile when N2 substituted by CO2. However, the presence of biomass in co-combustion with coal in addition to economic and environmental benefits increased the combustion performance of coal in both atmospheres.
CNPq: 134366/2015-8

Thesis (M.S.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains v, 126 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 59-69).

This thesis presents details of investigations into the potential for co-disposal of the two rejects from Clarence Colliery and Kable's Transport Sand Mine. Column experiments were undertaken to simulate field conditions. The experiment consisted of: 1/. creating the required co-disposal arrangement and structure in containers 2/. infiltrating water through each container and measuring the rates of infiltration and overflow 3/. measuring the chemical properties of the leachate water. Geotechnical tests of co-disposal pile stability were undertaken using a specially constructed shear box. Results of this study suggest the co-disposal of course coal washery reject from Clarence Colliery with clay tailings from Kable's Transport Sand Mine is a feasible option for managing the generation of acetic drainage. It is recommended that field trials comprise layers of coal reject and clay tailings in a 9:1 ratio. Layering the coal reject with clay tailings creates a semi-permeable barrier which acts to restrict water percolation through the reject as well as reacting with the leachate to increase the leachate pH and adsorb metals
Master of Engineering (Hons)

Nigeria is presently being faced with a growing electricity demand problem following its population growth rate. The total installed capacity is far less than the current demand for electricity supply. As a way of bridging out this supply gap, the federal government is mobilizing all of its potential energy options. Coal is widely used for power generation in many countries. But today, the continued usage of coal for power generation is being challenged by the disturbing global warming phenomenon. This is due to the quantity of uncontrolled carbon dioxide emission from traditional coal-fired power plants. The aim of this dissertation is to critically analyse the future of the Nigerian coal power stations following the need to do carbon dioxide emission control necessary for ensuring a sustainable environment. Achieving this aim entails the appraisal of environmental regulation standards and cost structures of carbon dioxide (C02) emission reduction options for the coal power stations. Controlling carbon dioxide emission from existing coal power stations requires retrofit system that captures and effectively sequestrates the captured CO2. The cost and performance effect of the CO2 retrofit system on the existing power plant can be simulated with standard computer software models. In this study the lECM-cs computer modelling tool for power plants was used in determining the cost and performance impacts of applying an Amine-based C02 capture system to the Oji river power station in Nigeria. With the lECM-cs model, it was established that reducing C02 emission imposes an additional cost on the power plant which increases the unit cost of electricity generated. This additional cost index requires economic justification for its acceptance. This is due to the need to demonstrate its viability judging from the cost of electricity generated from other sources in the Nigerian economy. For the Oji river case, the station is old and requires extensive renovation. This causes a cost escalation over and above the cost associated with the CO2 sequestration system. As such, Oji coal power station does not have an economic future if C02 emission sequestration becomes obligatory. The future of coal power stations in Nigeria can be considered from two scenarios: one where the current national environmental standard is retained and another where it is revised. The revision classifies CO2 as a pollutant which makes its emission reduction imperative for coal power plants. Under the current standard, building modern large capacity pulverized coal-fired power plants with improved steam cycles should be encouraged. But with the review of the national standard, the focus should be on building new large capacity coal power stations with integrated CO2 emission control. This will ensure an environmentally friendly future for coal power stations in Nigeria.
Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.

Hemp, eucalyptus, coal, hemp and coal blended fuel, and eucalyptus and coal blended fuel were ashed and then heat treated for 1 hour at temperatures from 600-1100°C. X-ray diffraction analysis indicated reactions between the phases present after initial ashing of the fuel showed biomass-biomass, biomass-coal and coal-coal interactions. Two phase systems were identified as dominant in the biomass and coal ash blends, these were CaO-MgO-SiO2 and CaO-Al2O3-SiO2. The phases identified in these systems have also been identified in ceramics produced at high temperatures which have similar compositions to the ash matrix of the laboratory synthesised ash; this indicates that phase diagrams can be powerful tools in phase formation prediction. Structures identified as trichomes (phosphate-silicate structures with melting points above 1100°C) from the hemp fuel which had not decomposed were present in both the hemp ash and the hemp and coal ash. The composition determined by Energy-dispersive X-ray spectroscopy analysis of laboratory synthesised ashes was also in agreement with the phases identified through X-ray diffraction. Hemp and coal, eucalyptus and coal, and eucalyptus ash samples (deposited, quenched, cyclone, and bottom ash) removed from a full scale 1MWth combustion rig were analysed. Phase composition of the fly ash samples are similar to those identified in the analagous samples produced in the laboratory with several of the same phases present; confirming that laboratory testing is useful for the predictions of phases present on the industrial scale combustion rig. Particle morphology is one of the largest differences between the laboratory scale tests and combustion rig samples. The dominant particle shape of fly ash particles removed from the combustion rig is spherical. These particles of characteristic shape are often referred to as plerospheres and cenospheres and were first identified in coal fly ash. The presence of the spheres in the combustion rig when only biomass (eucalyptus) is present indicates the formation mechanism of the particles is similar to that of coal. There are similarities between the chemical composition of the spheres which are solely of biomass origin and co-fired; it is likely that phase composition of the sphere and not the fuel origin contributes to the formation of the spheres. Phases identified in the bottom ash are similar to those identified in the fly ash. High temperature phases such as (e.g. Ca9MgK(PO4)7) ocur in the bottom ash suggesting that higher temperatures are reached in the bottom of the rig than in the flue gas. Analysis of 15Mo3 alloy corrosion coupons with fly ash deposited onto the surface, alongside the interactions between gas phases and coupons, deposits and coupons, and gas phases and deposits, showed that some oxidation/reduction of the metal had occurred. The presence vi of metal oxide flakes indicated corrosion. Oxidation of 15Mo3 alloy was observed in hemp and coal, and eucalyptus and coal combustion trials, likely due to the observed deposition of potassium chloride which has caused detachment of several scales. Between the metal-deposit interface, hematite whiskers were observed; magnetite octahedra were also present on the surface of scales. The phases present in the coupon deposit ash differ from those observed in the laboratory and fly ash due to the length of time spent in the high temperature environment. This indicates that some phases will not form until the deposits have built up and are in the furnace for an extended period of time. When the coupon samples were coated, fewer metal scales were observed meaning that the coatings are an affective method of corrosion reduction leading to an increased lifetime of boiler components. The dominant particle morphology present in the combustion rig is the cenospheres and plerospheres. The phases formed can be broadly catergorised into CaO-MgO-SiO2, CaO-Al2O3-SiO2, and K2O-Al2O3-SiO2 phases. Potassium chloride is observed in the laboratory ash and combustion rig ash indicating, alongside the presence of metal oxide scales, that the fuel blends are likely to lead to corrosion during combustion.

Cold water immersion is commonly used to alleviate the stress and damage that ensues following strenuous exercise. Alongside its purported performance and analgesic benefits recent literature highlights the positive impact it may have towards endurance adaptive responses, particularly on key markers of mitochondrial biogenesis. Despite these recent advances showing PGC-1α, the ‘master regulator’ of mitochondrial biogenesis, being augmented in its post-exercise response by cold water immersion, the precise controlling mechanisms remain to be determined. However, it has been suggested that local cooling effects on AMPK and p38 MAPK related signalling and/or increased systemic β-adrenergic stimulation are involved. Study 1 (Chapter 4) examined whether post-exercise cold-water immersion induced augmentation of PGC-1α mRNA is mediated through local or systemic mechanisms. Participants completed acute cycling followed by seated-rest (CON) or single-leg cold-water immersion (CWI; 10 min, 8°C) with muscle biopsies obtained pre-, post- and 3 h post-exercise from a single limb in the CON condition but from both limbs in CWI (thereby providing tissue from a CWI and non-immersed limb, NOT). Muscle temperature decreased following CWI (-5°C), with lesser changes observed in CON and NOT (-3°C; P<0.05). A significant interaction effect was present for AMPK phosphorylation (P=0.031). Exercise (CON) increased gene expression of PGC-1α 3 h post-exercise (~5-fold; P<0.001). Post-exercise CWI augmented PGC-1α expression above CON in immersed (CWI; ~9-fold; P=0.003) and NOT limbs (~12-fold; P=0.001). Plasma Normetanephrine concentration was higher in CWI vs. CON post-immersion (860 vs. 665 pmol·L-1; P=0.034). Data herein reports for the first time that local cooling of the immersed limb evokes transcriptional control of PGC1-α in the non-immersed limb, suggesting increased systemic β-adrenergic activation of AMPK may mediate, in part, post-exercise cold-induction of PGC-1α mRNA. Study 2 (Chapter 5) assessed the impact of combining a post-exercise cooling stimulus with prior low glycogen as both stressors are shown to separately enhance the post-exercise PGC-1α response. A single-leg depletion protocol and bi-lateral muscle biopsies with and without post-exercise CWI were utilised to give the following conditions: High glycogen control (HI CON), Low glycogen control (LO CON), High glycogen CWI (HI CWI) and Low glycogen CWI (LO CWI). HI limbs began the experimental day ~190 mmol·kg-1dry weight (dw) with low limbs at ~85 mmol·kg-1dw glycogen before undergoing the same relative exercise protocol as Chapter 4. PGC-1α mRNA was different between conditions (P = 0.039) with HI glycogen limbs showing greater expression than contralateral LO glycogen limbs (P < 0.05). PGC-1α mRNA increased to a greater extent in CWI HI vs. CON HI (ES 0.67 Large). Data herein supports previous research that shows post-exercise CWI is able to augment PGC-1α above the exercise response alone, however this response was not evident in heavily depleted limbs (~85 mmol·kg-1dw), suggesting a critical threshold may exist for the expected enhancement of PGC-1α to occur when exercise is commenced in a low glycogen state. Chapter 6 sought to examine the contribution of CWI (Chapter 4, Experiment 1) and/or low muscle glycogen (Chapter 5, Experiment 2) in the activation of PGC-1α via either the canonical (Exon 1a) or the alternative promoter (Exon 1b) regions. Data was obtained using muscle biopsy samples collected from the previous chapters (Chapter 4 and 5). Exercise increased the expression of promoter specific PGC-1α, with greater fold changes seen in Exon 1b. Experiment 1 (Chapter 4) showed PGC-1α Exon 1b expression closely matched the pattern of expression seen for total-PGC-1α, with large, systemic cold-induced increases in the non-immersed (NOT, 2344 fold change from Pre, P = 0.010) and immersed (CWI, 1860 fold change from Pre, P = 0.07), compared with the control limb (CON, 579 fold change from Pre). Results from experiment 2 (Chapter 5) saw PGC-1α Exon 1a and 1b gene expression increase post-exercise, with the Exon 1b response showing lower fold-changes at 3h post-exercise compared to those from Experiment 1 (chapter 4), despite the same exercise protocol being utilised (~200 fold increases in experiment 2 vs. ~2000 fold increases in experiment 1). The data suggests that depletion exercise in the days prior to the experimental day may have raised basal RNA levels, which may have therefore contributed to dampened fold-changes seen post-exercise when relativized to pre-exercise values. The lack of a cold augmentation in promoter specific PGC-1α gene expression in experiment 2 suggests this response may be extremely acute, and may not occur when cooling is undertaken on the third day of exercise. This thesis provides a novel insight into the influence of local, systemic and upstream activating mechanisms regulating the post-exercise, post-cooling and exercising in low glycogen states upon PGC-1α. These findings provide mechanistic application for future study designs and practical application in the support for the use of CWI when the intended target is an upregulation of the gene PGC-1α.