Study on the simulation of source-separated combustible solid waste fluidized bed gasification based on Aspen Plus

Abstract

A comprehensive process model was carried out for source-separated combustible solid waste gasification in an atmospheric fluidized bed gasifier by using the Aspen Plus simulator. The simulation was based on the principle of minimum Gibbs free energy and mass/energy balance. Gasification temperature, air equivalence ratio (ER) and air-preheating temperature are the primary influencing factors on gasification characteristics. Simulation results showed that CO volume percent increased with increasing ER but CH4 revealed an inverse trend. H2 and CO2 volume percent increased with an increasing ER at the beginning of the simulation. As the simulation progressed, the relationship between H2, CO2 and ER reversed. H2 and CO2 attained their maximum concentration when ER was 0.5. When ER was constant, H2, CO volume percent increased as air-preheating temperature increased while CH4 showed an inverse trend. CO2 volume percent increased with increasing ­air-preheating at first, however, as the simulation progressed, the relationship between CO2 and air-preheating reversed. CO2 attained its turning point when ER was 0.4. The lower heating value (LHV) of syngas decreases rapidly with increasing ER and the effect of ER on LHV is more obvious than that of air-preheating temperature. With increasing ER, gasification gas yield presents an approximate linear increasing trend while gasification efficiency shows an inverse trend. Air-preheating temperature has little influence on gasification gas yield and gasification efficiency.