Comparative study on the effect of H2O/air/CO2 on the gasification results of wheat straw

This study focuses on straw gasification technology, providing a comprehensive analysis of experimental results under three distinct gasification agents: air, CO2, and H2O. The effects of gasification temperature and the quantity of gasification agent on the distribution of gasification products were systematically investigated. Furthermore, the differences in gas and solid products generated under these three gasification conditions were thoroughly examined. In H2O gasification, the primary gas products are H-2 and CO, whereas CO2 gasification predominantly yields CO. The gas composition in air gasification is highly dependent on the amount of air introduced. Specifically, a lower air content (<30 %) tends to favor the production of H-2, while a higher air content (>30 %) promotes the generation of CO2. Significant differences were also observed in the structural composition of the solid carbon residues produced under the three gasification conditions. Due to the presence of oxygen, the carbon residue obtained from air gasification primarily consists of various oxides, with minimal carbon content and a relatively small specific surface area. In contrast, the carbon residues from CO2 and H2O gasification are dominated by an amorphous carbon structure. The activation effect of these gasification media results in carbon residues with a larger specific surface area compared to those produced by air gasification.