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Abstract(s)
O intuito deste trabalho consistiu no dimensionamento de um reator de pirólise de leito fluidizado borbulhante cujo principal objetivo é a produção de bio-óleo. Para tal, foi necessário escolher o tipo de biomassa adequada, o reator adequado e estudar as condições de operação que maximizam a produção desejada. A biomassa selecionada foi o Miscanthus sinensis, um tipo de biomassa com bastante capacidade de utilização e já com algum trabalho experimental realizado. O reator escolhido foi o de leito fluidizado borbulhante, devido ao facto de obter um maior rendimento para o componente desejado (bio-óleo), ter uma configuração simples e o seu scale up ser possível. As condições operatórias escolhidas basearam-se em trabalho experimental publicado na literatura. O caudal mássico de biomassa a usar foi de 100 g/min. A temperatura de operação do reator será de 500ºC, o meio fluidizante foi azoto com uma velocidade superficial de 0,3 m/s, o sólido inerte selecionado foi areia. O rendimento obtido através do conhecimento da composição elementar da biomassa e utilizando o método proposto por Neves para a previsão de componentes voláteis para o bio-óleo foi de 58,4%, um valor típico para este processo. Os gases não condensáveis apresentaram um rendimento de 23,6% e o carbonizado tem um rendimento de 19,4% (em base seca). Para que este processo ocorra é necessária uma potência térmica total de 4,26 kW. O reator funciona nas condições desejadas, ou seja, ocorre fluidização e borbulhamento e não ocorre o fenómeno de slugging. Este tem 0,25m de diâmetro e 0,55m de altura. Por outro lado, nenhum tipo de partículas é arrastado para fora do reator antes da reação e o carbonizado consegue ser separado totalmente apenas com o ciclone dimensionado. Existe ainda um condensador de tubos concêntricos com uma área de transferência de calor de 0,278 m2 .
The purpose of the present work is the design of a bubbling bed pyrolysis reactor, whose main objective is the production of bio oil. To perform this, it is necessary to choose the type of suitable biomass, the appropriate reactor and to study the operating conditions that maximize the desired production. The selected biomass was Miscanthus sinensis, a type of biomass with enough capacity of use and already with some experimental work. The reactor chosen was a bubbling fluidized bed, because it allows obtaining a higher yield for the desired component (bio oil), has a simple configuration and its scale up is relatively easy. The operating conditions chosen were based on experimental work already done. The biomass mass flow rate to be used is 100 g/min. The reactor temperature will be 500 °C, the fluidizing medium will be nitrogen at a superficial velocity of 0,3 m/s, the inert chosen was sand. The yield obtained through the knowledge of the elemental composition of the biomass and using the method proposed by Neves for the prediction of volatile components for the bio oil was 58,4%, a typical value for this process. The non-condensable gases have a yield of 23,6% and the char has a yield of 19,4% (dry basis). For this process to occur, a total thermal power of 4,26 kW is required. The reactor operates under the desired conditions, fluidization and bubbling occurs and the phenomenon of slugging does not. The reactor has 0,25m in diameter and 0,55m in height. On the other hand, no kind of particles are drawn out of the reactor prior to the reaction and the char can be totally separated with the dimensioned cyclone. There is also a concentric tube heat exchanger with a heat transfer area of 0.278 m2 .
The purpose of the present work is the design of a bubbling bed pyrolysis reactor, whose main objective is the production of bio oil. To perform this, it is necessary to choose the type of suitable biomass, the appropriate reactor and to study the operating conditions that maximize the desired production. The selected biomass was Miscanthus sinensis, a type of biomass with enough capacity of use and already with some experimental work. The reactor chosen was a bubbling fluidized bed, because it allows obtaining a higher yield for the desired component (bio oil), has a simple configuration and its scale up is relatively easy. The operating conditions chosen were based on experimental work already done. The biomass mass flow rate to be used is 100 g/min. The reactor temperature will be 500 °C, the fluidizing medium will be nitrogen at a superficial velocity of 0,3 m/s, the inert chosen was sand. The yield obtained through the knowledge of the elemental composition of the biomass and using the method proposed by Neves for the prediction of volatile components for the bio oil was 58,4%, a typical value for this process. The non-condensable gases have a yield of 23,6% and the char has a yield of 19,4% (dry basis). For this process to occur, a total thermal power of 4,26 kW is required. The reactor operates under the desired conditions, fluidization and bubbling occurs and the phenomenon of slugging does not. The reactor has 0,25m in diameter and 0,55m in height. On the other hand, no kind of particles are drawn out of the reactor prior to the reaction and the char can be totally separated with the dimensioned cyclone. There is also a concentric tube heat exchanger with a heat transfer area of 0.278 m2 .
Description
Keywords
Pirólise Bio-óleo Reator de leito fluidizado borbulhante Biomassa Pyrolysis Bio-oil Bubbling bed reactor Biomass