Characteristics of Gas–Liquid–Solid Products in Corn Straw Gasification: Effect of the Char–Tar–H₂O Interaction

The characteristics of gas–liquid–solid products during corn straw–H 2 O gasification were studied by the one-stage fluidized-bed/fixed-bed quartz reactor. The results indicate that the transformation between gas and solid products is mainly presented with the increase of feeding time (0–40 min). The aromaticity of biochar decreases slightly in the feeding period of 10–20 min but gradually increases in 20–40 min. The oxygen-containing functional groups in biochar increase gradually with the increase of the feeding time. The K content in biochar increases by 27% in 10–30 min, while that of Ca increases by 36% in 10–20 min. When the carbon conversion rate is less than 8%, the reactivity of biochar produced by 30 min of feeding is highest. The contents of phenol and 2,3-dihydrobenzofuran of tar increase by 25 and 34%, respectively in 20–40 min. The char–tar–H 2 O interaction in biomass gasification is a two-stage reaction. The first stage is dominated by the volatile–char interactions, while the second stage is mainly due to the char–H 2 O reaction.