A multi-stage co-gasification system of biomass and municipal solid waste (MSW) for high quality syngas production

Abstract

Air and air-steam co-gasification of switchgrass (SG) and municipal solid waste (MSW) was simulated using Aspen Plus software. The proposed model is composed of four main parts, i.e. dryer, pyrolyzer, tar combustor and char gasifier. To validate the model, the simulated results were compared with the experimental data in terms of gas composition. The effect of co-gasification ratio (CGR) and steam/feed ratio (S/F) on gas composition, the product yield and gasification performance was studied. Results showed that maximum lower heating values (LHV) of 5.11 MJ/Nm3, H2 content of 13.66 vol%, dry gas yield of 1.39 Nm3/kg, carbon conversion efficiency (CCE) of 48.9%, and cold gas efficiency (CGE) of 39.92% were obtained for air-steam gasification of MSW and SG at the temperature of 800 °C, CGR of 40% and S/F of 1.2. When S/F increased from 0.8 to 1.2, the tar yield slightly decreased from 16.08 to 15.41 g/Nm3. With increasing CGR from 0% to 40%, CGE initially increased from 28.81% to 29.25% and then decreased to 27.11%. Unlike CGE, CCE and dry gas yield continuously decreased from 42.97% to 39.28% and 1.22 Nm3/kg to 1.16 Nm3/kg with increasing CGR from 0% to 40%, respectively.