Application of mineral bed materials during fast pyrolysis of rice husk to improve water-soluble organics production

Fast pyrolysis of rice husk was performed in a spout-fluid bed to produce water-soluble organics. The effects of mineral bed materials (red brick, calcite, limestone, and dolomite) on yield and quality of organics were evaluated with the help of principal component analysis (PCA). Compared to quartz sand, red brick, limestone, and dolomite increased the yield of the water-soluble organics by 6–55% and the heating value by 16–19%. The relative content of acetic acid was reduced by 23–43% with calcite, limestone and dolomite when compared with quartz sand. The results from PCA showed all minerals enhanced the ring-opening reactions of cellulose into furans and carbonyl compounds rather than into monomeric sugars. Moreover, calcite, limestone, and dolomite displayed the ability to catalyze the degradation of heavy compounds and the demethoxylation reaction of guaiacols into phenols. Minerals, especially limestone and dolomite, were beneficial to the production of water-soluble organics.