| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 6.48 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
O presente trabalho centrou-se no estudo do aproveitamento energético do eucalipto num reator de gasificação em leito fluidizado borbulhante, tendo-se realizado também o seu dimensionamento. Foi estudado um modelo de equilíbrio estequiométrico, de forma a avaliar a composição da fase gasosa produzida e comparar com o previsto por outros autores. Por fim, avaliou-se a potência térmica de gasificação e determinaram-se os parâmetros relativos à eficiência da gasificação. Como condições de operação considerou-se pressão de 1 atm, temperaturas de gasificação na gama de 750 º C a 900 ºC e, como agentes de gasificação vapor de água, oxigénio e vapor combinado com oxigénio. Considerou-se também razão de equivalência, ER, igual a 0,2 e razão entre caudal mássico de vapor e de biomassa, SBR, igual a 1. Relativamente à temperatura de gasificação, verificou-se que teve pouca influência na composição dos gases de saída. No entanto, o seu efeito foi mais notório, quando se utilizou como agente gasificante vapor de água e vapor de água combinado com oxigénio. Face aos resultados obtidos no estudo do tipo de agente de gasificação concluiu-se que o vapor de água permitiu obter um gás com maior teor de H2, cerca de 56 %. Utilizando oxigénio verificou-se um maior teor de CO, cerca de 57%, enquanto utilizando vapor de água combinado com oxigénio verificou-se maior teor de CO2, cerca de 24 %. Quando se utilizou vapor de água o teor de CH4 presente no gás foi mais elevado e apresentou valores entre 2,3 % e 0,7 %. A maior potência térmica obtida apresenta valores entre 1,4 e 1,9 kW e foi conseguida com vapor de água. Relativamente aos parâmetros que caracterizam a gasificação também se verificou que a temperatura praticamente não tem influência, e a utilização de vapor de água permitiu obter parâmetros mais elevados. Assim, para uma temperatura constante, igual a 750 ºC, obteve-se valores de 2,1 m3 /kg, 1,2 e 11,1 MJ/m3 para rendimento do gás seco, eficiência do gás frio e poder calorifico superior do gás produzido, respetivamente. No que diz respeito ao dimensionamento do gasificador obteve-se uma altura de 1,30 m, para um diâmetro considerado de 70 mm.
The present work focused on the study of the energetic utilization of eucalyptus in a bubbling fluidized bed gasification reactor, having also performed its sizing. A stoichiometric equilibrium model was studied in order to evaluate the composition of the gas phase produced and compare it with that predicted by other authors. Finally, the gasification thermal power was evaluated and the gasification efficiency parameters were determined. The operating conditions considered were pressure of 1 atm, gasification temperatures in the range of 750ºC to 900ºC, and as gasification agents, water vapor, oxygen, and steam combined with oxygen. We also considered an equivalence ratio, ER, equal to 0.2 and a ratio between steam and biomass mass flow, SBR, equal to 1. Regarding the gasification temperature, it was found to have little influence on the composition of the output gases. However, its effect was more noticeable when water steam and water steam combined with oxygen were used as gasifying agents. In view of the results obtained in the study of the type of gasifying agent, it was concluded that water vapor allowed for obtaining a gas with a higher content of H2, around 56%. Using oxygen resulted in a higher CO content, about 57%, while using steam combined with oxygen resulted in a higher CO2 content, about 24%. When water vapor was used the CH4 content in the gas was higher and presented values between 2.3 % and 0.7 %. The highest thermal power obtained presents values between 1.4 and 1.9 kW and was achieved with water vapor. Regarding the parameters that characterize the gasification it was also verified that the temperature has practically no influence, and the use of water vapor allowed higher parameters to be obtained. Thus, for a constant temperature, equal to 750 ºC, values of 2.1 m3 /kg, 1.2 and 11.1 MJ/m3 were obtained for dry gas yield, cold gas efficiency and higher calorific value of the produced gas, respectively. Regarding the sizing of the gasifier a height of 1.30 m was obtained, for a considered diameter of 70 mm.
The present work focused on the study of the energetic utilization of eucalyptus in a bubbling fluidized bed gasification reactor, having also performed its sizing. A stoichiometric equilibrium model was studied in order to evaluate the composition of the gas phase produced and compare it with that predicted by other authors. Finally, the gasification thermal power was evaluated and the gasification efficiency parameters were determined. The operating conditions considered were pressure of 1 atm, gasification temperatures in the range of 750ºC to 900ºC, and as gasification agents, water vapor, oxygen, and steam combined with oxygen. We also considered an equivalence ratio, ER, equal to 0.2 and a ratio between steam and biomass mass flow, SBR, equal to 1. Regarding the gasification temperature, it was found to have little influence on the composition of the output gases. However, its effect was more noticeable when water steam and water steam combined with oxygen were used as gasifying agents. In view of the results obtained in the study of the type of gasifying agent, it was concluded that water vapor allowed for obtaining a gas with a higher content of H2, around 56%. Using oxygen resulted in a higher CO content, about 57%, while using steam combined with oxygen resulted in a higher CO2 content, about 24%. When water vapor was used the CH4 content in the gas was higher and presented values between 2.3 % and 0.7 %. The highest thermal power obtained presents values between 1.4 and 1.9 kW and was achieved with water vapor. Regarding the parameters that characterize the gasification it was also verified that the temperature has practically no influence, and the use of water vapor allowed higher parameters to be obtained. Thus, for a constant temperature, equal to 750 ºC, values of 2.1 m3 /kg, 1.2 and 11.1 MJ/m3 were obtained for dry gas yield, cold gas efficiency and higher calorific value of the produced gas, respectively. Regarding the sizing of the gasifier a height of 1.30 m was obtained, for a considered diameter of 70 mm.
Description
Keywords
Eucalipto Gasificação Gás de síntese Modelo de equilíbrio Eucalyptus Gasification Syngas Equilibrium model