(25c) Experimental and Numerical Study on Combining Anaerobic Digestion and Gasification for Potential Energy Recovery from Biomass and Sewage Sludge

The purpose of this study is to improve energy recovery and realize full utilization of municipal solid wastes (MSWs). This paper proposes a novel concept of a two-stage MSWs disposal process that combines the anaerobic digestion and biomass gasification. Both experimental and numerical studies have been conducted to investigate the performance of an integrated system for the energy recovery from MSWs based on anaerobic digestion and gasification. The experiments are performed at two stages. At the first stage, anaerobic digestion of MSWs, such as grass, leaves and animal manure, is conducted by mixing with anaerobic sludge. At the second stage, the digested solid residue is co-gasified with woody biomass for syngas production. The effect of inoculum to substrate ratio on anaerobic digestion and wood chips to digested solid residue ratio on gasification performance are investigated respectively. A combined kinetic model is then built for prediction and optimization of biogas and syngas yields in this two-stage process. The deviation between the numerical and experimental results obtained was lower than 10%. Both experimental and numerical results show that full utilization of MSWs can be realized to produce energy through anaerobic digestion followed by gasification process.