Exergy analysis of updraft and downdraft fixed bed gasification of village-level solid waste

The most commonly used for gasification of village-level solid waste is the fixed-bed gasifier, but there is no reasonable method to evaluate the gasification process. This paper attempts to find a gasifier that is most suitable for gasification of village-level solid wastes through exergy analysis method. Based on experimental data from literature, the exergy efficiencies and LHV(Low Heat Value) of product gas from updraft and downdraft fixed bed gasifier are studied in this paper. The results show that the updraft fixed bed gasifier has higher exergy efficiency, and the gas produced by the downdraft fixed bed gasifier has a higher heating value. Air gasification has higher exergy efficiency than steam gasification and pure oxygen gasification. The highest exergy efficiency at a gasification temperature of about 1000 °C and ER (Equivalence Ratio) value in the range of 0.33–0.36. The volatile content of gasification raw materials is higher, and the gasification efficiency is higher. Through the research of this paper, a new path to reasonably evaluate the gasification process is obtained.