O crescimento do potencial energético a partir da biomassa estimula o desenvolvimento e a criação de novas tecnologias neste setor. Neste trabalho realizou-se uma ampla pesquisa da produção, compressão e acondicionamento do biogás. Constatou-se durante essa pesquisa a necessidade da busca por alternativas que possibilitem a utilização eficiente deste biocombustível. Analisou-se a possibilidade da fabricação de um compressor alternativo para biogás que possa ser aplicado em pequenas unidades de produção por meio da modelagem das partes componentes. Primeiro efetuou-se a escolha do material considerando-se as características adequadas para construção do sistema de compressão. Depois disto dimensionou-se a camisa de compressão e a sua modelagem tridimensional com software Inventor 2010 (versão Student), além de válvulas e matrizes para fabricação. Complementarmente foi simulado o funcionamento do compressor (gráfico do deslocamento, velocidade e força com o software FluidSim da Festo Didatic). Por último executou-se o projeto eletropneumático, energização e lista de dispositivos necessários para montagem do compressor. Observou-se que essa tecnologia pode ser aplicada em pequenas plantas de produção de biogás. A comparação com outros sistemas de compressão revelou vantagens como a não haver contaminantes na compressão e acionamento, além da compressão poder se dar em ambiente separado do seu acionamento. / The growth of the energy potential from the biomass stimulates development and creation of new technologies in this sector. In this work is carried out extensive research in production, compression and biogas bottling. The need to search for alternatives has been evidenced during the research to make possible the efficient use of biofuel. After it analyzed the possibility of manufacturing of an alternative compressor for biogas which can be applied in small production units through the modeling of the contracting parties. At first it was effected the material choice considering the characteristics for the construction of the compression system. After this, was dimensioned a compression jacket, valves and matrices with the Student software Inventor 2010. Moreover the functioning of the compressor was simulated (its graphical of the displacement, speed and force with a FluidSim software from Festo Didatic). Finally was made a pneumatic project and was executed a list of necessary devices for the compressor assembly. It was observed to that this technology can be applied in small plants of production of biogas. The comparison with other systems of compression demonstrates that tis compressor haven’t contaminants, beyond the compression to be able to give itself in separate environment of its drive.

O crescimento do potencial energético a partir da biomassa estimula o desenvolvimento e a criação de novas tecnologias neste setor. Neste trabalho realizou-se uma ampla pesquisa da produção, compressão e acondicionamento do biogás. Constatou-se durante essa pesquisa a necessidade da busca por alternativas que possibilitem a utilização eficiente deste biocombustível. Analisou-se a possibilidade da fabricação de um compressor alternativo para biogás que possa ser aplicado em pequenas unidades de produção por meio da modelagem das partes componentes. Primeiro efetuou-se a escolha do material considerando-se as características adequadas para construção do sistema de compressão. Depois disto dimensionou-se a camisa de compressão e a sua modelagem tridimensional com software Inventor 2010 (versão Student), além de válvulas e matrizes para fabricação. Complementarmente foi simulado o funcionamento do compressor (gráfico do deslocamento, velocidade e força com o software FluidSim da Festo Didatic). Por último executou-se o projeto eletropneumático, energização e lista de dispositivos necessários para montagem do compressor. Observou-se que essa tecnologia pode ser aplicada em pequenas plantas de produção de biogás. A comparação com outros sistemas de compressão revelou vantagens como a não haver contaminantes na compressão e acionamento, além da compressão poder se dar em ambiente separado do seu acionamento. / The growth of the energy potential from the biomass stimulates development and creation of new technologies in this sector. In this work is carried out extensive research in production, compression and biogas bottling. The need to search for alternatives has been evidenced during the research to make possible the efficient use of biofuel. After it analyzed the possibility of manufacturing of an alternative compressor for biogas which can be applied in small production units through the modeling of the contracting parties. At first it was effected the material choice considering the characteristics for the construction of the compression system. After this, was dimensioned a compression jacket, valves and matrices with the Student software Inventor 2010. Moreover the functioning of the compressor was simulated (its graphical of the displacement, speed and force with a FluidSim software from Festo Didatic). Finally was made a pneumatic project and was executed a list of necessary devices for the compressor assembly. It was observed to that this technology can be applied in small plants of production of biogas. The comparison with other systems of compression demonstrates that tis compressor haven’t contaminants, beyond the compression to be able to give itself in separate environment of its drive.

<p>För att minska dagens klimatpåverkan krävs fullgoda energialternativ till de fossila bränslena. Utsläpp från fossila bränslen är idag en av de största orsakerna till de negativa klimatförändringar som sker på jorden. Genom en ökad användning av alternativa fossilfria drivmedel kan en tydlig minskning av koldioxidutsläpp till atmosfären ske. Biogas är ett sådant fossilfritt drivmedel som idag klassas som ett av de renaste. Biogasen framställs från olika typer av restprodukter från samhället. Då fossila drivmedel ersätts med biogas sker en total reduktion av växthusgaser.</p><p>Kalmar Län har som mål att till år 2030 vara en helt fossilbränslefri region. Genom en ökad användning av gasen inom transportsektorn kan sådana typer av nationella mål uppfyllas. Västervik kommun i Kalmar Län har sedan 2008 producerat biogas lokalt, vilket bidrog till att en tankstation kunde öppnas under år 2009. Genom dessa åtgärder har kommunen genomfört ett stort steg för biogasens utveckling och framfart i samhället. Då tillgängligheten är säkrad är det upp till individer och företag att avgöra om de sedan väljer att nyttja gasen som fordonsbränsle. Detta val kräver en förändring av ett tidigare beteende. En attitydförändring är därför viktig om en förändring ska kunna ske. Det finns många olika faktorer och argument som påverkar övergången från en miljövänlig attityd till ett miljövänligt beteende.</p><p>Syftet med detta arbete var utifrån denna bakgrund att undersöka vilka faktorer som påverkar valet av fordonsbränsle hos privatpersoner och företag. Detta möjliggjordes genom en enkätundersökning för privatpersoner och ett frågeformulär för företag. Genom att privatpersoner och företag som både använder biogas och fossila bränslen ingick i undersökningen kunde dessa senare jämföras för att den aktuella frågeställningen skulle kunna besvaras. Undersökningen var av intresse för Västervik kommun, varav privatpersoner deltog både från kommunen och runt om i landet. 612 personer svarade på enkäten, 336 gasanvändare och 276 fossilanvändare. Sammanlagt ingick fem lokala företag i undersökningen samt tre lokala bilfirmor.</p><p>Genom undersökningen kunde intressanta typer av mönster urskiljas gällande de attityder och faktorer som låg till grund för de val som privatpersonerna har gjort. Fossilanvändare ansåg att ekonomi är den viktigaste faktorn vid valet av bränsle. En ökad ekonomi eller ett minskat pris på gasfordon skulle kunna medföra en övergång till biogas. Gasanvändare har utvecklat ett miljövänligt beteende genom användandet av gasen, där det starkaste argumentet var just ett rent miljösamvete som biogasanvändningen bidrar till. Det framkom även att biogassystemet måste fungera som helhet för att en ökad användning ska kunna möjliggöras, då en del gasanvändare påpekade brister i det nuvarande systemet. För företag var även ekonomi och miljösamvete viktiga faktorer vid val av fordonsbränsle. Att biogasfordon har ett reducerat förmånsvärde var en viktig faktor för företags investering. Detta var även något som bilfirmor påpekade och att det hos privatpersoner trots allt är den egna plånboken som styr valet. Biogas är i dagsläget ett miljömässigt bra drivmedel och tidigare forskning har dessutom visat att det finns god potential till betydande förbättringar i framtiden.</p> / <p>Fossil fuels are amongst the largest contributors to the climate changes currently happening. Through an increased use of alternative fossil-free fuel it is possible to achieve a significant reduction of carbon dioxide emissions to the atmosphere. One such fuel is biogas, which is considered as one of the cleanest fuels available today. Biogas is produced from various types of waste materials, and replacing fossil fuel with biogas results in an overall reduction of green-house gas emissions.</p><p>The Kalmar County has set a target to become a completely fossil fuel-free region by the year 2030. Through an increased use of biogas in the transport sector, such types of national targets can be achieved. The Municipality of Västervik, a part of the Kalmar County, has since 2008 been producing biogas locally, which meant that a fuelling station could be built in 2009 and through this, the Municipality has taken a major step towards an increased use of biogas. With supply secured, it is up to individuals and companies to use it for vehicle fuel. This choice requires a change in human habits. The motivations for making changes vary among individuals and theirs attitudes.</p><p>The aim of this study was to examine which factors affect the choice of vehicular fuel among individuals and companies. This was achieved through a survey for individuals and a questionnaire for companies. Individuals and companies could then be compared to. The study was made for the Municipality of Västervik, and the study subjects were both local and non-local residents. 612 people replied to the survey, 336 users of gas and 276 users of fossil fuels. Totally five local companies were included in the survey and three local Car Dealers.</p><p>In this study, a number of interesting patterns regarding attitudes and affecting factors have been observed. Users of fossil considered the economic aspect as the most important factor for their choice. Users of gas have adopted environmentally friendly habits through the use of gas, where the strongest argument was the environmentally friendly approach. It was also found that biogas must be part of a coherent system in order to increase use; some biogas users pointed on shortcomings in the current system. The economic aspects and the environmental conscience were also important for companies for theirs choice of vehicles. The reduced benefit value was an important factor for investment of biogas vehicles. This was also something that Car Dealers pointed out; it is after all the own wallet that govern elections. Biogas is an environmentally friendly fuel in the current situation and previous research has also shown that there is good potential for significant improvements in the future.</p>

För att minska dagens klimatpåverkan krävs fullgoda energialternativ till de fossila bränslena. Utsläpp från fossila bränslen är idag en av de största orsakerna till de negativa klimatförändringar som sker på jorden. Genom en ökad användning av alternativa fossilfria drivmedel kan en tydlig minskning av koldioxidutsläpp till atmosfären ske. Biogas är ett sådant fossilfritt drivmedel som idag klassas som ett av de renaste. Biogasen framställs från olika typer av restprodukter från samhället. Då fossila drivmedel ersätts med biogas sker en total reduktion av växthusgaser. Kalmar Län har som mål att till år 2030 vara en helt fossilbränslefri region. Genom en ökad användning av gasen inom transportsektorn kan sådana typer av nationella mål uppfyllas. Västervik kommun i Kalmar Län har sedan 2008 producerat biogas lokalt, vilket bidrog till att en tankstation kunde öppnas under år 2009. Genom dessa åtgärder har kommunen genomfört ett stort steg för biogasens utveckling och framfart i samhället. Då tillgängligheten är säkrad är det upp till individer och företag att avgöra om de sedan väljer att nyttja gasen som fordonsbränsle. Detta val kräver en förändring av ett tidigare beteende. En attitydförändring är därför viktig om en förändring ska kunna ske. Det finns många olika faktorer och argument som påverkar övergången från en miljövänlig attityd till ett miljövänligt beteende. Syftet med detta arbete var utifrån denna bakgrund att undersöka vilka faktorer som påverkar valet av fordonsbränsle hos privatpersoner och företag. Detta möjliggjordes genom en enkätundersökning för privatpersoner och ett frågeformulär för företag. Genom att privatpersoner och företag som både använder biogas och fossila bränslen ingick i undersökningen kunde dessa senare jämföras för att den aktuella frågeställningen skulle kunna besvaras. Undersökningen var av intresse för Västervik kommun, varav privatpersoner deltog både från kommunen och runt om i landet. 612 personer svarade på enkäten, 336 gasanvändare och 276 fossilanvändare. Sammanlagt ingick fem lokala företag i undersökningen samt tre lokala bilfirmor. Genom undersökningen kunde intressanta typer av mönster urskiljas gällande de attityder och faktorer som låg till grund för de val som privatpersonerna har gjort. Fossilanvändare ansåg att ekonomi är den viktigaste faktorn vid valet av bränsle. En ökad ekonomi eller ett minskat pris på gasfordon skulle kunna medföra en övergång till biogas. Gasanvändare har utvecklat ett miljövänligt beteende genom användandet av gasen, där det starkaste argumentet var just ett rent miljösamvete som biogasanvändningen bidrar till. Det framkom även att biogassystemet måste fungera som helhet för att en ökad användning ska kunna möjliggöras, då en del gasanvändare påpekade brister i det nuvarande systemet. För företag var även ekonomi och miljösamvete viktiga faktorer vid val av fordonsbränsle. Att biogasfordon har ett reducerat förmånsvärde var en viktig faktor för företags investering. Detta var även något som bilfirmor påpekade och att det hos privatpersoner trots allt är den egna plånboken som styr valet. Biogas är i dagsläget ett miljömässigt bra drivmedel och tidigare forskning har dessutom visat att det finns god potential till betydande förbättringar i framtiden. / Fossil fuels are amongst the largest contributors to the climate changes currently happening. Through an increased use of alternative fossil-free fuel it is possible to achieve a significant reduction of carbon dioxide emissions to the atmosphere. One such fuel is biogas, which is considered as one of the cleanest fuels available today. Biogas is produced from various types of waste materials, and replacing fossil fuel with biogas results in an overall reduction of green-house gas emissions. The Kalmar County has set a target to become a completely fossil fuel-free region by the year 2030. Through an increased use of biogas in the transport sector, such types of national targets can be achieved. The Municipality of Västervik, a part of the Kalmar County, has since 2008 been producing biogas locally, which meant that a fuelling station could be built in 2009 and through this, the Municipality has taken a major step towards an increased use of biogas. With supply secured, it is up to individuals and companies to use it for vehicle fuel. This choice requires a change in human habits. The motivations for making changes vary among individuals and theirs attitudes. The aim of this study was to examine which factors affect the choice of vehicular fuel among individuals and companies. This was achieved through a survey for individuals and a questionnaire for companies. Individuals and companies could then be compared to. The study was made for the Municipality of Västervik, and the study subjects were both local and non-local residents. 612 people replied to the survey, 336 users of gas and 276 users of fossil fuels. Totally five local companies were included in the survey and three local Car Dealers. In this study, a number of interesting patterns regarding attitudes and affecting factors have been observed. Users of fossil considered the economic aspect as the most important factor for their choice. Users of gas have adopted environmentally friendly habits through the use of gas, where the strongest argument was the environmentally friendly approach. It was also found that biogas must be part of a coherent system in order to increase use; some biogas users pointed on shortcomings in the current system. The economic aspects and the environmental conscience were also important for companies for theirs choice of vehicles. The reduced benefit value was an important factor for investment of biogas vehicles. This was also something that Car Dealers pointed out; it is after all the own wallet that govern elections. Biogas is an environmentally friendly fuel in the current situation and previous research has also shown that there is good potential for significant improvements in the future.

Made available in DSpace on 2014-06-11T19:35:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-05Bitstream added on 2014-06-13T18:47:02Z : No. of bitstreams: 1 lamas_wq_dr_guara.pdf: 876448 bytes, checksum: 84281f8365b2bd1b6c356067b0c6c181 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho é desenvolvida uma metodologia para a alocação dos custos dos produtos por uma mini-estação de tratamento de esgotos, com vistas a realizar a análise da viabilidade econômica do investimento necessário para a sua implantação, inclusive caracterizando-a como a melhor escolha a ser adotada na solução de saneamento básico em zonas rurais e em regiões de limitado poder aquisitivo, além de que tem potencial energético face à sua capacidade de transformar em eletricidadea energia contida no biogás gerado. Essa metodologia á aplicada ao sistema instalado no campus de Guaratinguetá da Faculdade de Engenharia da Universidade Estadual Paulista, tendo sido estabelecidas as condições iniciais a partir da realidade vivida no campus e sendo relacionadas as características termodinâmicas do sistema, a partir do seu diagrama de processo. As características associadas ao diagrama de processo possibilitam construir o diagrama funcional termoeconômico do sistema e determinar as equações referentes às funções exergéticas desse sistema e os respectivos valores das exergias associados. Após esses cálculos, elabora-se um modelo estrutural para avaliar os custos de seus produtos (biogás, biofertilizante, água em condições de re-uso e energia elétrica) e avaliar a viabilidade econômica em função do retorno de capital investido. A seguir, a mesma metodologia á aplicada a um sistema comercialmente disponível, com características de tratamento muito próximas às da mini-ETE. A partir dos resultados obtidos, é possível verificar que a mini-estação de tratamento de esgoto é uma alternativa viável e muito atraente sobre o ponto de vista técnico-econômico, pois além de apresentar auto-suficiência energética, possui um retorno de investimento de aproximadamente um terço do tempo do sistema comercialmente disponível com características semelhantes para tratamento. / In this work a methodology that allows for the allocation of costs of the generated products for a small wastewater treatment station is developed, and used to perform an analysis of its economic feasibility, to justify the investment, beside its characterization as one of the best choice to be adopted as a basic sanitation solution in rural areas, and in areas characterized by low income population, together with a major energy potential because of its capability to transform the generated biogas into electric energy. For this purpose, the methodology is applied to a system established at Guaratinguetá Campus, School of Engineering, São Paulo State University. After establishing initial conditions based on site evaluation, the thermodynamics features of the system are related based on its process diagram. Such features, associated to process diagram, make it possible to build the thermoeconomi functional diagram for the system under analysis and, after words, the equations related to exergetic functions for the system are determined and the exergy values are calculated. After these calculations, a structural model is developed, in order to provide its products costs (biogas, biofertilizer, water in reuse conditions and electric energy). The economic viability is evaluated as a function of the estimated return on investment. The same methodology is then applied to a commercially available system, with characteristics close to a small wastewater treatment station. Based on the results of this work it is possible to verify that the small wastewater treatment station is a viable and attractive alternative in the technical and economic point of view, showing self-sufficiency in energy, and a pay-back period about one-third of estimated time of the commercial system referred to with similar features.

Made available in DSpace on 2014-06-11T19:24:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-27Bitstream added on 2014-06-13T18:20:57Z : No. of bitstreams: 1 machado_cr_me_botfca.pdf: 313360 bytes, checksum: 89e639c32ee6924dbc36e6125aca66dd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Objetivou-se de avaliar a biodigestão anaeróbia e produção de biogás de dejetos de vacas leiteiras submetidos a diferentes tempos de exposição ao ar. Primeiramente foram coletados 300 kg de dejetos produzidos em 24 horas, que foram conduzidos ao pátio de armazenamento. A cada três dias, durante 18 dias, fazia-se o abastecimento dos biodigestores. Os biodigestores foram abastecidos com os dejetos provenientes da leira nos tempos de exposição zero (0d), três (3d), seis (6d), nove (9d), 12 (12d), 15 (15d) dias e 18 (18d) dias de exposição. A redução de massa foi avaliada em relação à matéria seca e à matéria natural do dejeto. A redução de massa da leira foi de 73 % em 18 dias. Os teores de ST dos tratamentos variaram de 17,8 % a 27,3 % e os teores de SV de 79,93 % a 73,8 %. O valor de pH variou de 7,38 a 9,24. Os picos de produção de biogás com elevado teor de CH4 foram mais adiantados quando os substratos foram obtidos nos maiores tempos de exposição, tornando evidente que uma fermentação prévia dos dejetos antes do abastecimento de biodigestores é conveniente para o adiantamento da produção de biogás. Em relação aos teores de metano, embora não se tenha observado diferença entre os tratamentos, houve diferença entre as semanas de leitura (P<0,05), em que nas quatro primeiras semanas os teores de metano foram menores do que os teores apresentados na quinta e na sexta semana. Houve diferença (P<0,05) entre os tratamentos para os potenciais de produção de biogás em relação aos ST adicionados, do estrume e dos substratos, sendo as melhores médias as dos tratamentos oriundos da leira após seis, nove e 12 dias de exposição / This study aimed to evaluate the anaerobic biodigestion and production of biogas from manure of dairy cows subjected to different times of exposure to air. First was collected 300 kg of waste produced within 24 hours, which were driven to the storage yard, and every three days, during 18 days, was made the supply of the biodigesters. The biodigesters were supplied with slurry from the pile in the exposure zero (0d), three (3d), six (6d), nine (9d), 12 (12d), 15 (15d) and day 18 (18d) days of the exposure. The reduction in mass was evaluated in terms of dry matter and matter's natural manure. The reduction in mass was 73% in 18 days. The levels of TS ranged from 17,8% to 27,3% and the levels of VS 79,93% to 73,8%. The pH ranged from 7,38 to 9,24. The peak production of biogas was earlier when the substrates were in the larger day, making clear that a prior fermentation of manure digesters before the supply is convenient for the advancement of biogas production. In relation to content of methane, but would not give significant difference between treatments was no significant difference between the days of reading (P <0.05), in which the first four readings of methane levels were lower than the levels presented in the fifth and sixth reading. Statistically significant (P <0.05) among treatments for the potential of ST added, manure and the substrate, and the best means of treatment from the following pile six, nine and 12 days of exposure

Orientador: Pedro Magalhães Sobrinho / Co orientador: José Luz Silveira / Banca: Marcio Abud Marcelino / Banca: Christian Jeremi Coronado Rodríguez / Resumo: Nos dias de hoje é essencial a busca por novas fontes energéticas, não somente pelos aspectos ambientais e seus respectivos gases poluentes, que contribuem para o aumento do efeito estufa em nosso planeta, mas também como uma forma de desenvolver novas tecnologias, reduzindo cada vez mais nossa dependência global em uma matriz energética. Cada vez mais a tendência de um sistema mais produtivo com o confinamento de animais, em unidades restritas, acaba gerando grandes problemas ambientais devido a alta geração de resíduos com sua indevida disposição no solo. Devido a esta realidade, os biodigestores se apresentam como uma boa alternativa, não só na redução da contaminação ambiental, como na produção de energia. Neste estudo foi realizada uma análise técnica e econômica entre uma microturbina e um motor de combustão interna, a fim de analisar a aplicabilidade de ambas as tecnologias, através da quantidade e forma de energia necessárias ao local, os custos de investimento e o tempo de retorno do capital. Por fim, foram estudados os aspectos ambientais, calculados através da eficiência ecológica, realizando uma comparação entre o gás natural e o biogás, ambos os combustíveis sendo queimados em microturbinas e motores de combustão interna. / Abstract: Today it is essential to search for new energy sources, not only for their environmental and greenhouse gases, which contribute to the enhanced greenhouse effect on our planet, but also as a way to develop new technologies, reducing more our dependence on a global energy matrix. Increasingly, the trend of a more productive with the confinement of animals in restricted units, it generates large environmental problems due to high waste generation with their improper disposal in the ground. Due to this fact, the digesters are presented as a good alternative, not only in reducing environmental contamination, such as in energy production. This study was carried out a technical and economic analysis of a microturbine and an internal combustion engine in order to analyze the applicability of both technologies, and by the amount of energy required to form local investment costs and time to return the capital. Finally, we studied the environmental, ecological efficiency calculated by, making a comparison between natural gas and biogas, both fuels being burned in microturbines and internal combustion engines. / Mestre

Made available in DSpace on 2014-06-11T19:30:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-10Bitstream added on 2014-06-13T19:39:25Z : No. of bitstreams: 1 govoni_jb_me_guara.pdf: 3573500 bytes, checksum: da2782aa8bd86007fc34cc1d44a8ae6c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Nos dias de hoje é essencial a busca por novas fontes energéticas, não somente pelos aspectos ambientais e seus respectivos gases poluentes, que contribuem para o aumento do efeito estufa em nosso planeta, mas também como uma forma de desenvolver novas tecnologias, reduzindo cada vez mais nossa dependência global em uma matriz energética. Cada vez mais a tendência de um sistema mais produtivo com o confinamento de animais, em unidades restritas, acaba gerando grandes problemas ambientais devido a alta geração de resíduos com sua indevida disposição no solo. Devido a esta realidade, os biodigestores se apresentam como uma boa alternativa, não só na redução da contaminação ambiental, como na produção de energia. Neste estudo foi realizada uma análise técnica e econômica entre uma microturbina e um motor de combustão interna, a fim de analisar a aplicabilidade de ambas as tecnologias, através da quantidade e forma de energia necessárias ao local, os custos de investimento e o tempo de retorno do capital. Por fim, foram estudados os aspectos ambientais, calculados através da eficiência ecológica, realizando uma comparação entre o gás natural e o biogás, ambos os combustíveis sendo queimados em microturbinas e motores de combustão interna. / Today it is essential to search for new energy sources, not only for their environmental and greenhouse gases, which contribute to the enhanced greenhouse effect on our planet, but also as a way to develop new technologies, reducing more our dependence on a global energy matrix. Increasingly, the trend of a more productive with the confinement of animals in restricted units, it generates large environmental problems due to high waste generation with their improper disposal in the ground. Due to this fact, the digesters are presented as a good alternative, not only in reducing environmental contamination, such as in energy production. This study was carried out a technical and economic analysis of a microturbine and an internal combustion engine in order to analyze the applicability of both technologies, and by the amount of energy required to form local investment costs and time to return the capital. Finally, we studied the environmental, ecological efficiency calculated by, making a comparison between natural gas and biogas, both fuels being burned in microturbines and internal combustion engines.

The main purpose of this project was an attempt to modulate and simulate two existing biogas plant, situated in Lidköping and Katrineholm, Sweden and evaluate how the process reacts to certain conditions regarding feeding, layout and substrate mixture. The main goal was to optimize the existing processes to better performance. Both the modeling and simulation were executed in SIMBA#Biogas with accordance to the real conditions at the plant in question. The simulation of each model was validated against data containing measurements of, CH4 yield, CH4 production, TS, VS, NH4-N concentration and N-total concentration. The data was obtained from each plant in accordance with scheduled follow ups. Both models were statistically validated for several predictions. Predictions of N-total and NH4-N concentration failed for some cases. Both plants were tested with new process lay outs, where promising results were obtained. The Lidköping model was provided with a post-hygienization step to handle ABPs. The Katrineholm model was provided with a dewatering unit, where 35% of the centrate was recirculated back to the system. Both setups was configured to yield the highest CH4 production. This study suggests that SIMBA#Biogas can be a tool for predictions and optimizations of the biogas process.

The study has explored the social sustainability of biogas production in a local village of Sogwala which is located in the Lower Gweru District of Zimbabwe. The social sustainability assessment was based on the two concepts of social sustainability, namely human capital and social capital with particular emphasis on their respective elements and aspects. Qualitative and quantitative research methodology methods were used on a sample of 100 households using biogas and some key informants. Analysis of the variance was used to determine whether biogas production could account for any effects on the social and human capital elements of the Sogwala community. An overview and descriptive statistics analysis of the findings from the study have been provided where the biogas users’ experiences, perspectives are discussed and results were assessed. For instance, effects on the aspects of social capital elements which include increases in the social group membership of households after the introduction of biogas production the village; the performance of biogas energy as compared with other fuel sources in terms of accessibility, efficiency and the degree of labour needed for continual production of biogas. In view of the human capital element, assessment is done on the economic status per household before and after the production of biogas, where emphasis is placed on the aspects of employment, education and health indicators within the social sustainability context. The fundamental benefits from biogas production are considered and discussed with the technical issues surrounding biogas production also being presented. This is not just a technical unit for providing alternative energy supply, but it requires management, labour and knowledge, skills to operate on a daily basis for it to have an impact that can bring positive change to the daily social lives of both the young and old.