Effect of K and Ca elements on transient light hydrocarbons and oxygen-containing gases during biomass fast pyrolysis

K and Ca elements in the biomass are in the form of inorganic and organic matter. AAEM species affect the chain scission and depolymerization process during the biomass pyrolysis of lignin, cellulose and hemicellulose molecules. To a certain extent, it affects the formation and transformation of biomass pyrolysis gas. In the process of pyrolysis reaction, the intermediate transient product has a very important significance for the formation of final product during the pyrolysis reaction. In this paper, biomass (rice husk) was treated with acid washing, and then the directional load of K, Ca elements, respectively. By using Py-GC/MS in the pyrolysis temperature of 500-900℃, the experimental study on rapid pyrolysis of biomass was carried out. By gas chromatography mass spectrometry (GC/MS), a semi quantitative analysis was made on the types and contents of light hydrocarbons and oxygen-containing species. It explained the effect of K and Ca elements on the transient light hydrocarbons and oxygen-containing species during biomass fast pyrolysis and the formed mechanism transformation of pyrolysis gas phase. At low temperature (≤600℃), fast pyrolysis instantaneous gas products of H-form, K-loaded and Ca-loaded biomass were mainly CO, CO₂ and CH₄. K and Ca elements promoted the generation of CO and CO₂. However, at high temperature (≥700℃), C₃H₆ became the main transient gas products. Ca element had a certain promotion effect on the formation of C₃ (C₃H₆), while K element inhibited the generation of C₃H₆.