Aspectos termodinâmicos, ecológicos e econômicos de sistemas de cogeração com motores de combustão interna operando com gás natural, biogás e gás de síntese
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Data
2016-08-05
Autores
Xavier, Beatriz Helene [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A preocupação com o meio ambiente e com a qualidade do ar têm sido crescente e objeto de diversos estudos. Quanto maior a densidade populacional, maior a necessidade de consumo de energia e consequentemente, maiores os índices de emissões de poluentes. Neste sentido, é essencial a procura por novas fontes e sistemas mais eficientes de geração de energia, a fim de reduzir os níveis de poluição, diminuir o efeito estufa sobre o planeta, e, principalmente, reduzir a dependência de petróleo na matriz energética mundial. Partindo deste conceito e considerando aspectos técnicos, econômicos e ecológicos, neste trabalho analisam-se três casos de cogeração utilizando motores de combustão interna (MCI) operando com gás natural em comparação com biogás e gás de síntese (syngas), ambos provenientes da biomassa. São aplicadas metodologias de pesquisadores renomados, com o objetivo de determinar a eficiência de geração de eletricidade, a eficiência de geração de calor e a eficiência global dos sistemas, e ainda como parte da análise técnica, determinam-se índices de correlação entre a produção térmica e a potência elétrica dos motores, tornando previsível a capacidade de produção de água quente, vapor e água gelada, dependendo da capacidade elétrica do motor a ser utilizado na implantação de sistemas de cogeração. São determinados os custos de geração de eletricidade e calor, período de retorno dos investimentos e posteriormente são estudadas as emissões de CO2, NOx, SOx, MP e o CO2 equivalente para a determinação do indicador de poluição e da eficiência ecológica dos sistemas de cogeração considerados nesta dissertação. Conclui-se com o estudo realizado que os biocombustíveis são uma importante fonte energética que vem ganhando espaço dia a dia. Na análise ambiental, o gás natural perdeu em eficiência ecológica tanto para o biogás como para o gás de síntese, e a análise energética comprovou que não há grandes perdas na utilização de biocombustíveis em substituição ao gás natural. No aspecto econômico, o biogás demonstrou-se como o mais rentável frente aos combustíveis estudados, apresentando rapidez no retorno dos investimentos e baixo custo de produção elétrica e térmica.
The concern with the environment and air quality has increased and subjected to several studies. The higher the population density, the greater the need for energy consumption and therefore higher pollutant emission rates. In this regard, the search for new sources and more efficient systems for power generation is essential in order to reduce pollution levels and the greenhouse effect on the planet, and, most importantly, reduce dependence on oil in the global energy matrix. Based on this concept and considering the technical, economic and ecological aspects, this paper analyzes three cases of cogeneration using internal combustion engines (ICEs) operating with natural gas in comparison with biogas and synthesis gas (syngas), both stemming from biomass. Methodologies from renowned researchers are applied, with the aim of determining the efficiency of electricity generation, heat generation efficiency and the overall efficiency of the systems; furthermore, as part of the technical analysis, we determine correlation coefficients between the thermal production and the power capacity of the engine, making it possible to predict hot, steam and cold water production capacities, depending on the engine power capacity used in the implementation of the cogeneration system. We determine the costs of generating electricity and heat, the payback period and then CO2, NOx, SOx, MP and equivalent CO2 emissions are studied in order to determine the pollution indicator and ecological efficiency of cogeneration systems considered in this thesis. From this study we conclude that the biofuels are an important energy source which is becoming increasingly popular. In the environmental analysis, the natural gas was less ecologically efficient than both the biogas and the syngas, and the technical analysis showed that there are not great losses when using biofuels in place of the natural gas. In the economic analysis, the biogas was the most feasible in comparison with the natural gas and the syngas, with a short payback period and low power and thermal production costs.
The concern with the environment and air quality has increased and subjected to several studies. The higher the population density, the greater the need for energy consumption and therefore higher pollutant emission rates. In this regard, the search for new sources and more efficient systems for power generation is essential in order to reduce pollution levels and the greenhouse effect on the planet, and, most importantly, reduce dependence on oil in the global energy matrix. Based on this concept and considering the technical, economic and ecological aspects, this paper analyzes three cases of cogeneration using internal combustion engines (ICEs) operating with natural gas in comparison with biogas and synthesis gas (syngas), both stemming from biomass. Methodologies from renowned researchers are applied, with the aim of determining the efficiency of electricity generation, heat generation efficiency and the overall efficiency of the systems; furthermore, as part of the technical analysis, we determine correlation coefficients between the thermal production and the power capacity of the engine, making it possible to predict hot, steam and cold water production capacities, depending on the engine power capacity used in the implementation of the cogeneration system. We determine the costs of generating electricity and heat, the payback period and then CO2, NOx, SOx, MP and equivalent CO2 emissions are studied in order to determine the pollution indicator and ecological efficiency of cogeneration systems considered in this thesis. From this study we conclude that the biofuels are an important energy source which is becoming increasingly popular. In the environmental analysis, the natural gas was less ecologically efficient than both the biogas and the syngas, and the technical analysis showed that there are not great losses when using biofuels in place of the natural gas. In the economic analysis, the biogas was the most feasible in comparison with the natural gas and the syngas, with a short payback period and low power and thermal production costs.
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Palavras-chave
Cogeração de energia, Biocombustíveis, Geração descentralizada de energia, Cogeneration, Natural gas, Biofuels, Renewable energy systems