Avaliação exergética do ciclo de vida de um ciclo combinado a gás natural com sistema de oxicombustão
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Data
2020-03-24
Autores
Cruz, Tatiane Tobias da
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Universidade Estadual Paulista (Unesp)
Resumo
O crescimento populacional e o progresso tecnológico têm levado a crescente demanda por recursos naturais e energia, resultando na intensificação de impactos ambientais. O setor de energia é um dos principais emissores de CO2 antropogênico, principalmente devido a utilização de combustíveis fósseis, o que tem levado à busca por soluções tecnológicas visando a redução dos impactos ambientais associados à sua geração. Nesse contexto, esse trabalho visa realizar uma avaliação de desempenho ambiental da geração de energia elétrica das centrais termelétricas Fernando Gasparian e Piratininga com inserção da técnica de captura de CO2 por oxicombustão. Essa avaliação é realizada por meio de uma proposta conceitual própria que inclui avaliação do ciclo de vida (ACV) e avaliação termodinâmica com bases exergéticas. A avaliação termodinâmica abrange a operação das termelétricas, por meio de análise energética e exergética utilizando a teoria do custo exergético e o método CExC (cumulative exergy consumption). A ACV abrange desde a extração dos recursos até o fim de vida das instalações, utilizando os métodos de contabilização de recursos CED (cumulative energy demand), CExD (cumulative exergy demand) e CML IA baseline. Os resultados da avaliação termodinâmica permitiram verificar que a câmara de combustão é a principal destruidora de exergia e a inserção da técnica de oxicombustão impõe maior penalidade energética por causa da inserção dos componentes de separação de ar e processamento de CO2 para armazenamento. Por essa razão, um aumento do custo exergético unitário e consumo de recursos de mais de 15% para as UTE com oxicombustão foi encontrado. Do ponto de vista do ciclo de vida, os resultados demonstraram que a operação da termelétrica é responsável por cerca de 86% das emissões de GEE (GWP100) para o cenário sem oxicombustão e 69% para o cenário com oxicombustão. A produção e transporte do gás natural foi responsável por cerca de 14% (sem oxicombustão) e 28% (com oxicombustão), sendo as emissões restantes ocorridas na construção e descomissionamento das UTE (0,22% sem oxicombustão e 0,32% com oxicombustão). O consumo de energia (CED) e exergia (CExD), de maneira geral são maiores nas etapas de extração, processamento e transporte do gás natural. Conclui-se que a proposta conceitual apresentada foi validada como forma de avaliação ambiental do ponto de vista termodinâmico e do ciclo de vida com bases exergéticas
Population growth and technological progress have led to an increasing demand for natural resources and energy, resulting in the intensification of environmental impacts. The energy sector is one of the main emitters of anthropogenic CO2, mainly due to the use of fossil fuels, which has led to the search for technological solutions aimed at reducing the environmental impacts associated with its generation. In this context, this work aims to carry out an environmental performance evaluation of the electric power generation at the Fernando Gasparian and Piratininga thermoelectric plants with the insertion of the CO2 capture technique by oxy-combustion. This assessment is carried out through a conceptual proposal that includes life cycle assessment (LCA) and thermodynamic assessment with exergetic bases. Thermodynamic evaluation covers the operation of thermoelectric plants, through energy and exergetic analysis using the theory of exergetic cost and the CExC method (cumulative exergy consumption). ACV covers everything from resource extraction to the end of the facility's life, using the resource accounting methods CED (cumulative energy demand), CExD (cumulative exergy demand) and CML IA baseline. The results of the thermodynamic evaluation allowed to verify that the combustion chamber is the main destroyer of exergy and the insertion of the oxy-combustion technique imposes a greater energy penalty due to the insertion of the air separation unit and CO2 processing unit for CO2 storage. For this reason, an increase in the unit exergetic cost and resource consumption of more than 15% for the plant with oxy-combustion was found. From the life cycle point of view, the results showed that the operation of the thermoelectric plant is responsible for about 86% of the GHG emissions (GWP100) for the scenario without oxy-combustion and 69% for the scenario with oxy-combustion. The production and transportation of natural gas was responsible for about 14% (without oxycombustion) and 28% (with oxy-combustion), with the remaining emissions occurring in the construction and decommissioning of the UTE 0.22% without oxy-combustion and 0.32% with oxy-combustion. Energy (CED) and exergy (CexD) consumption, in general, are higher in the stages of extraction, processing and transportation of natural gas. It can be concluded that the conceptual proposal presented was validated as a form of environmental assessment from the point of view of thermodynamics and of the life cycle with exergetic bases
Population growth and technological progress have led to an increasing demand for natural resources and energy, resulting in the intensification of environmental impacts. The energy sector is one of the main emitters of anthropogenic CO2, mainly due to the use of fossil fuels, which has led to the search for technological solutions aimed at reducing the environmental impacts associated with its generation. In this context, this work aims to carry out an environmental performance evaluation of the electric power generation at the Fernando Gasparian and Piratininga thermoelectric plants with the insertion of the CO2 capture technique by oxy-combustion. This assessment is carried out through a conceptual proposal that includes life cycle assessment (LCA) and thermodynamic assessment with exergetic bases. Thermodynamic evaluation covers the operation of thermoelectric plants, through energy and exergetic analysis using the theory of exergetic cost and the CExC method (cumulative exergy consumption). ACV covers everything from resource extraction to the end of the facility's life, using the resource accounting methods CED (cumulative energy demand), CExD (cumulative exergy demand) and CML IA baseline. The results of the thermodynamic evaluation allowed to verify that the combustion chamber is the main destroyer of exergy and the insertion of the oxy-combustion technique imposes a greater energy penalty due to the insertion of the air separation unit and CO2 processing unit for CO2 storage. For this reason, an increase in the unit exergetic cost and resource consumption of more than 15% for the plant with oxy-combustion was found. From the life cycle point of view, the results showed that the operation of the thermoelectric plant is responsible for about 86% of the GHG emissions (GWP100) for the scenario without oxy-combustion and 69% for the scenario with oxy-combustion. The production and transportation of natural gas was responsible for about 14% (without oxycombustion) and 28% (with oxy-combustion), with the remaining emissions occurring in the construction and decommissioning of the UTE 0.22% without oxy-combustion and 0.32% with oxy-combustion. Energy (CED) and exergy (CexD) consumption, in general, are higher in the stages of extraction, processing and transportation of natural gas. It can be concluded that the conceptual proposal presented was validated as a form of environmental assessment from the point of view of thermodynamics and of the life cycle with exergetic bases
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Palavras-chave
ACV, Exergia, AECV, Central termelétrica, Gás Natural, Captura de carbono, Oxicombustão, LCA, Exergy, ELCA, Power plant, Natural Gas, Carbon capture, Oxy-combustion, Usinas termoelétricas, Análise energética, Sequestro de caborno, Ciclo de vida do produto - aspectos ambientais