CPFD simulations of corn stalk gasification in a circulating fluidized bed

Gasification is one of the most widely-used methods for biomass utilization owing to its environmental friendliness and high economic benefits. In this study, a three-dimensional compressible computational particle fluid dynamics (CPFD) model of a 20 MW circulating fluidized bed (CFB) gasifier was established using the Euler-Lagrangian method. The model, which incorporates heat and mass transfer, phase behavior, and chemical reaction, was validated using experimental data. Then, it was applied to investigate the effects of steam-to-biomass (S/B) ratio and carbon dioxide-to-biomass (C/B) ratio on gasification performance of corn stalk. The results indicate that increasing the S/B ratio reduces the gasifier temperature and significantly reduces the tar yield, while increasing the C/B ratio slightly reduces the tar yield. Furthermore, an appropriate increase in the amount of steam in the gasifier is significantly beneficial to the yield of H2, while the addition of CO2 is somewhat beneficial to the production of CO. Hence, selecting suitable gasification agents can effectively increase the H2/CO ratio of the produced syngas.