Brazil is one of the largest biomass producers in the world, thus it has a huge potential for biogas production across all its territory. Nowadays, biogas production remains largely unexplored, representing just a small fraction of its potential. The adoption of biogas technologies has grown over the past years, but it is unevenly distributed across Brazilian states. This master thesis investigates the conditions under which the widespread diffusion of biogas technologies can be enabled in the Brazilian context by looking at the factors that influence the adoption of biogas technologies and why it differs across the Brazilian territory. Technological innovation systems (TIS), societal embedding, and diffusion of innovation theory are combined in the theoretical framework to create a broad understanding of the diffusion process of biogas technologies in Brazil. While TIS focusses on what are the functions been performed within the system, Societal embedding contributes to the understanding of why technological diffusion may not happen in the same way in different regions and how technologies are rooted in society. Diffusion of innovation theory adds to the importance of individual choices and strategies in the adoption of technologies. A comparative case study was design between the states São Paulo and Paraná. 16 semi-structured interviews served as the main research instrument with the support of document studies. When looking at the factors that could impact the adoption of biogas technologies the presence of specialized actors that can offer technical support to the implementation of projects locally proved to be positive considering that biogas technologies are still novel in Brazil. The unreliability of the energy grid in rural regions also favours the adoption of biogas technologies for electricity generation in agriculture properties that can combined waste treatment with energy security. Access to financial and human resources is still the largest barrier for the diffusion of biogas technologies. Financial institutions are at large unprepared to offer good conditions for the implementation of biogas projects, mainly because they do not understand the singularities of these projects. The adoption of biogas technologies in the case studies was mainly dictated by the economic activities in place, which shaped the view on biogas technologies. The complexities of the regulatory environment in Brazil could explain why electricity generation is still the main application of biogas technologies as the electricity market is regulated at national level while gas markets are the responsibility of individual states. When biogas technologies are portraited as a tool for sustainable development, other advantages of these technologies are highlighted – environmental and social benefits such as waste treatment and job creation – creating a better claim for biogas technologies which could boost adoption.

O presente trabalho realizou o estudo dos principais problemas dos motores movidos a biogás e das principais tecnologias de purificação do biogás em biometano. Para tanto, foram avaliados vários tipos de motores movidos a biogás e estudadas possíveis modificações para aumentar, consideravelmente, sua vida útil. Na purificação do biogás para produção de biometano, foram estudadas as mais diversas tecnologias disponíveis no mercado e na literatura, além da realização de um estudo de caso para melhoria da tecnologia no processo de purificação de biogás, ou seja, a biometanização utilizada na Granja Haacke. A configuração atual de purificação de biogás ocorre via processo físico-químico, utilizando uma coluna de limalha de ferro oxidada, para remoção da fração grosseira, principalmente, do H2S. A ocorrência de falhas ou manutenção desta fase do processo provoca a interrupção da operação. A segunda etapa de purificação consiste na utilização de duas colunas de adsorção tipo Pressure Swing Adsorption (PSA), cuja função é remover a fração resultante de CO2 da composição do biogás. Pode-se concluir que, a melhor proposta de upgrade para o estudo de caso seria introduzir, no início do processo, uma torre de biodessulfurização de biogás Thiobacillus ferroxidans, seguida de duas colunas de limalha de ferro oxidado, montadas em paralelo, para remoção de H2S e CO2, mantendo toda a configuração posterior para remoção da fração fina. Com isto, o sistema ficará, consideravelmente, ecoeficiente, pois reduzirá a produção de inservíveis, aumentando a vida útil dos filtros. / This investigation aimed to accomplish the study of the major problems of engines operating with biogas and the main purification technologies in biomethane. Therefore, was evaluated several types of engines operating with biogas and studied possible changes to improve significantly the lifetime. In the purification of biogas to produce biomethane, was studied several technologies available in the market and in literature, besides to accomplish a case study to improve the purification process, that is, the biomethanization used in Granja Haacke. The current configuration of biogas purification is via physical-chemical process using a rusty column iron for removal of the coarse fraction mainly H2S. The occurrence of faults or maintenance of this stage of the process causes the stop operation. The second step purification use two Pressure Swing Adsorption (PSA) columns whose function is to remove the resulting fraction of CO2 from biogas composition. We can conclude that the best proposal to case study upgrade would be introduced at the beginning of the process a biogas desulphurization tower of the Thiobacillus ferroxidans followed by two columns of rusty column iron mounted in parallel for removing H2S and CO2, and thus keep all subsequent setting for the fine fraction removal. With this the system will be considerably ecofriendly because will be reduced the scrap production increasing the lifetime of the filters.