Thermodynamic modeling of entrained-flow gasification of solid fuels covering biomass and coal categories: Model simplification, validation, and application

Abstract

In this study, a simplified stoichiometric equilibrium model dedicated to modeling entrained-flow gasification systems was proposed. The model was then validated by comparing its predicted results with experimental data obtained from lab-scale drop tube furnace (DTF) tests conducted in this study, a pilot- and industrial-scale entrained-flow coal gasifiers documented in literature. Finally, the model was used to investigate the gasification performance of 29 solid fuels belonging to biomass and coal categories. Model validation demonstrated that the applicable temperatures for the simplified model must exceed 1200 °C for coal and 1300 °C for biomass. At this temperature, a good consistency was observed between the predicted and the experimental gas compositions, regardless of the gasifier scales. The modeling investigation for 29 solid fuels based on the simplified model revealed that under high-temperature entrained-flow gasification conditions, the CO₂ and H₂O yields produced from biomass fuels were much higher than those from coals. Consequently, biomass fuels demonstrated poor performance indicators in terms of a reduced cold gas efficiency (CGE), elevated specific fuel consumption (SFC), and increased specific oxygen consumption (SOC) compared to coals. The addition of steam positively influenced gas quality for high-rank coals; however, it appeared economically disadvantageous for law-rank coal and biomass as it led to a reduction in CGE and an increase in SFC and SOC. The results of this work are expected to provide valuable insights into the design and optimal operation of entrained-flow gasification systems for various fuel categories.