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Abstract(s)
O objetivo deste trabalho foi o dimensionamento de um reator de leito fluidizado circulante para a pirólise de biomassa, com a finalidade de produzir bio-óleo. Como forma de aumentar eficiência energética do processo e torná-lo o mais autossuficiente possível, incorporou-se uma câmara de combustão para a queima do carbonizado produzido. A metodologia utilizada para dimensionar o reator permitiu garantir as condições ótimas para a produção do bio-óleo, como a temperatura, e o tempo de residência, mas respeitando as restrições impostas pela hidrodinâmica do leito. O reator foi dimensionado segundo dados experimentais do trabalho de Park et al.(2019) [1] para realizar os balanços de massa. Tendo em conta esses dados, a biomassa alimentada ao reator será o serrim com um caudal mássico, em base total, de 4 kg/h; o rendimento em bio-óleo previsto é de 60 %; e por sua vez, prevê-se um rendimento em gases de 25% e 15% em carbonizado (em base total). Com a finalidade de otimizar a produção de bio-óleo, o riser do reator opera a 500ºC e os gases circulam nestas condições num tempo de residência médio de 0,48 segundos. O meio fluidizante foi o ar que circula no riser a uma velocidade superficial de 4,77 m/s. Os sólidos inertes circulam pelo reator com um fluxo mássico de 28,6 kg/(m2 ∙s). O reator foi dimensionado com um diâmetro de 3,5 cm e uma altura de 2 metros. Considera-se um diâmetro demasiado reduzido, podendo afetar a estabilidade da operação do reator. A câmara de combustão foi dimensionada com um diâmetro de 9 cm e uma altura de 0,4 metros. Foram ainda dimensionados um ciclone para a separação das partículas sólidas dos gases/vapores produzidos, e um distribuidor de ar.
The objective of this work was to design a circulating fluidized bed reactor for biomass pyrolysis, with the intent to produce bio-oil. As a way to raise the energetic self- -sufficiency and reach an autothermal operation, a char combustion chamber was incorporated in the reactor. The reactor design methodology ensured the optimal conditions for bio-oil production, like reaction temperature, and residence time, but also respecting the restrictions imposed by the bed’s hydrodynamics. The reator was designed according to experimental data from Park’s et al.(2019) work [1] to perform the mass balances. Taking this dat into account, the selected biomass was sawdust, and it was fed into the reactor with a mass flow rate of 4 kg/h. The yield predicted for bio-oil is 60 %; 25% for gases and 15% for char (total base). With the intent to optimize bio-oil production, the reactor’s riser operates at 500 ºC and the gases flow in these conditions with an average residence time of 0,48 seconds. The selected fluidizing medium was air, which flows at a superficial velocity of 4,77 m/s in the riser. The inert solids flow through the reactor with a mass flux of 28,6 kg/(m2 ∙s). The riser was dimensioned with a diameter of 3,5 cm and a height of 2 m. It was considered an excessively small diameter, which can affect the reactor’s operation. The combustion chamber was dimensioned with a 9 cm diameter and a 0,4 m of height. A cyclone and an air distributor were also dimensioned as auxiliary equipment.
The objective of this work was to design a circulating fluidized bed reactor for biomass pyrolysis, with the intent to produce bio-oil. As a way to raise the energetic self- -sufficiency and reach an autothermal operation, a char combustion chamber was incorporated in the reactor. The reactor design methodology ensured the optimal conditions for bio-oil production, like reaction temperature, and residence time, but also respecting the restrictions imposed by the bed’s hydrodynamics. The reator was designed according to experimental data from Park’s et al.(2019) work [1] to perform the mass balances. Taking this dat into account, the selected biomass was sawdust, and it was fed into the reactor with a mass flow rate of 4 kg/h. The yield predicted for bio-oil is 60 %; 25% for gases and 15% for char (total base). With the intent to optimize bio-oil production, the reactor’s riser operates at 500 ºC and the gases flow in these conditions with an average residence time of 0,48 seconds. The selected fluidizing medium was air, which flows at a superficial velocity of 4,77 m/s in the riser. The inert solids flow through the reactor with a mass flux of 28,6 kg/(m2 ∙s). The riser was dimensioned with a diameter of 3,5 cm and a height of 2 m. It was considered an excessively small diameter, which can affect the reactor’s operation. The combustion chamber was dimensioned with a 9 cm diameter and a 0,4 m of height. A cyclone and an air distributor were also dimensioned as auxiliary equipment.
Description
Keywords
Leito fluidizado circulante Pirólise Bio-óleo Serrim Circulating fluidized bed Pyrolysis Bio-oil Sawdust