Indexed on: 08 Jun '14Published on: 08 Jun '14Published in: Bioresource Technology
Thermal decompositions of three components of biomass (cellulose, hemicellulose and lignin) were studied using nonisothermal thermogravimetric analysis (TGA) under both oxidative and inert atmospheres at a heating rate of 10 K min(-1). The multi-Gaussian-distributed activation energy model (DAEM)-reaction model was first developed to describe thermal decomposition behaviors of three components. Results showed that the presence of CO₂ enhanced the thermal decompositions of three components in high temperature range, but made little difference in low temperature range. Decomposition behaviors under CO₂ were analyzed by the two-stage reaction mechanism corresponding to the pyrolysis process of original materials and the gasification process of char. During gasification stage, CO₂ was reduced to CO, which provided a possibility of a reduction in greenhouse gas emissions. In addition, more CO was produced, and therefore the thermal value of gas was improved. The findings imply that CO₂ gasification technology of biomass has great research significance.