Pyrolysis characteristics of lignocellulosic biomass components in the presence of CaO

In this study, the reaction mechanism for the pyrolysis of cellulose, hemicellulose and lignin in the presence of CaO was examined using TG-FTIR and PY-GC/MS. Results indicated that, at low temperature (400-600 degrees C), in addition to H2O and CO2, acids and phenols from hemicellulose pyrolysis, sugars from cellulose pyrolysis and phenols from lignin pyrolysis would react with CaO. While, at elevated temperature (600 degrees C-800 degrees C), the catalytic effect of CaO was more obvious. In detail, in hemicellulose pyrolysis, CaO promoted the catalytic decarbonylation of ketones to form CO, and meanwhile, the formation of hydrocarbons was enhanced. For cellulose pyrolysis, the presence of CaO enhanced the ring-opening and dehydration reactions of sugars, and thus promoted the formation of light organics. As to the pyrolysis of lignin, CaO addition favored the radical reactions and thus increased the yield of CH4. In addition, those monohydric phenols with lower carbon numbers increased.