Modelagens do processo de gaseificação de fezes humanas: influência da temperatura, razão de equivalência e umidade do ar na composição do gás de Síntese

Abstract

In order to reduce the load of organic material in sewage systems, sustainable sanitation can separate solid waste for thermochemical conversion into gasification gas. The proposed solution aims to significantly reduce the environmental and health impacts of precarious sanitation, besides minimizing the use of water and energy, that are the main challenges for the growth of underdeveloped countries. The thermochemical conversion from fixed bed gasification can potentialize the generation of gaseous fuel through human fecal biomass, converting human waste into fuel gas of appropriate calorific value for power generation. Three models for a downdraft gasifier were proposed, using the processes simulator Aspen PlusTM, for validation and study of optimization of operational conditions. It was selected the model that presented satisfactory results and it was studied the applicability of human fecal biomass as fuel for the gasification process. It has been found that the gasification gas resulting from the human fecal biomass with 20% moisture got LHV and exergy of 7,43 MJ/kg and 8,17 MJ/kg, respectively, in the equivalence ratio of 0,2. The effect of the main operating parameters, such as reactor temperature, equivalence ratio and steam/biomass ratio about exergy were analyzed. It was observed that the use of gasifying agent with relative humidity 90% reduces the temperature of the gas in 4,52% and the exergy in 4,27%, for the equivalence ratio of 0,5. The impacts of this work lie in the use of validated models to assist the design of fixed bed gasifier and the maximization of operational conditions for thermochemical conversion of human fecal biomass.