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Abstract(s)
Este trabalho tem como intuito analisar a viabilidade de uma mini central a biomassa com forno rotativo. O estudo centrou-se na importância da biomassa, nas características do forno, na sua aplicação numa mini central a biomassa e na averiguação da viabilidade destas centrais. A biomassa destaca-se como uma fonte de energia despachável, neutra em carbono e renovável, quando utilizada de forma sustentável, tornando-se uma alternativa promissora para substituir as energias fósseis no setor eletroprodutor. Analisaram-se as mini centrais com forno rotativo ao nível do funcionamento, equipamentos, otimização e dificuldades operacionais. Avaliou-se a combustão no forno rotativo, revelando-se a necessidade de uma câmara de pós-combustão para garantir a oxidação total dos gases e conformidade com regulamentos ambientais. Demonstrou-se ser preferível utilizar o estagiamento de ar devido à redução simultânea de emissões de uma combustão incompleta e de NOx. Relativamente a aspetos particulares destas instalações, mostrou-se a importância de controlar o tempo de residência e assegurar uma mistura adequada dos sólidos, para permitir uma combustão completa e uniforme, e a necessidade de observar regularmente o estado do tijolo refratário, e a presença de fissuras e desalinhamento no forno, para garantir o seu bom funcionamento. A avaliação da viabilidade abrangeu os pontos de vista técnico, ambiental, económico e social. No ponto de vista técnico o forno destaca-se na versatilidade de queima de combustível, mas tem uma baixa eficiência térmica. Sob a perspetiva ambiental e social não se verificaram diferenças para outras tecnologias de combustão, mas evidenciou-se ser vantajoso, de uma forma geral, utilizar a biomassa. Economicamente, o forno tem um custo de investimento relativamente baixo, mas um custo de manutenção elevado. A baixa eficiência térmica e os custos de manutenção podem justificar a baixa utilização do forno rotativo em centrais termoelétricas a biomassa.
This work aims to conduct a feasibility analysis of a small scale biomass power plant with a rotary kiln. The study focused on the value of biomass, the characteristics of the kiln, its application in a small scale biomass plant, and the assessment of the feasibility of such facilities. Biomass stands out as a dispatchable, carbon-neutral, and renewable energy source, when utilized sustainably, emerging as a promising alternative to replace fossil fuels in the power generation sector. Small scale power plants with rotary kilns were analyzed, concerning their functioning, equipment, optimization, and operational challenges. Combustion in the kiln was also evaluated, revealing the need for a post-combustion chamber to ensure the complete oxidation of gases and compliance with environmental regulations. It proved preferable to implement air staging due to the simultaneous reduction of emissions from incomplete combustion and NOx. Regarding specific aspects of these facilities, the importance of monitoring residence time and ensuring an adequate mixture of solids was emphasized to enable complete and uniform combustion, and regular observation of the state of the refractory brick, along with the detection of cracks and misalignment in the kiln, was underscored to ensure its proper functioning. The feasibility assessment encompassed technical, environmental, economic, and social perspectives. From a technical standpoint, the kiln stands out in its versatility of fuel burning but has a low thermal efficiency. Regarding environmental and social aspects, no significant differences were observed compared to other combustion technologies, but it was generally evident that utilizing biomass is advantageous. Economically, the kiln has a relatively low initial investment cost, but high maintenance expenses. The combination of low thermal efficiency and maintenance costs may account for the limited utilization of rotary kilns in biomass power plants.
This work aims to conduct a feasibility analysis of a small scale biomass power plant with a rotary kiln. The study focused on the value of biomass, the characteristics of the kiln, its application in a small scale biomass plant, and the assessment of the feasibility of such facilities. Biomass stands out as a dispatchable, carbon-neutral, and renewable energy source, when utilized sustainably, emerging as a promising alternative to replace fossil fuels in the power generation sector. Small scale power plants with rotary kilns were analyzed, concerning their functioning, equipment, optimization, and operational challenges. Combustion in the kiln was also evaluated, revealing the need for a post-combustion chamber to ensure the complete oxidation of gases and compliance with environmental regulations. It proved preferable to implement air staging due to the simultaneous reduction of emissions from incomplete combustion and NOx. Regarding specific aspects of these facilities, the importance of monitoring residence time and ensuring an adequate mixture of solids was emphasized to enable complete and uniform combustion, and regular observation of the state of the refractory brick, along with the detection of cracks and misalignment in the kiln, was underscored to ensure its proper functioning. The feasibility assessment encompassed technical, environmental, economic, and social perspectives. From a technical standpoint, the kiln stands out in its versatility of fuel burning but has a low thermal efficiency. Regarding environmental and social aspects, no significant differences were observed compared to other combustion technologies, but it was generally evident that utilizing biomass is advantageous. Economically, the kiln has a relatively low initial investment cost, but high maintenance expenses. The combination of low thermal efficiency and maintenance costs may account for the limited utilization of rotary kilns in biomass power plants.
Description
Dissertação para obtenção do grau de Mestre em Engenharia Mecânica
Keywords
Biomassa Forno rotativo Mini central termoelétrica Estudo de viabilidade Biomass Rotary kiln Small scale thermoelectric plant
Citation
Cortes, Alexandre Jorge - Estudo da viabilidade de uma mini central a biomassa com forno rotativo. Lisboa: Instituto Superior de Engenharia de Lisboa, 2023. Dissertação de Mestrado