2008 Volume 87 Issue 10 Pages 852-861
This paper presents new pyrolysis model of wood and grass biomass. It is named biomass-CPD model. A scheme of the Chemical Percolation Devolatilization (CPD) model which was used in numerical analysis of coal pyrolysis was applied to description of wood and grass biomass pyrolysis. Cellulose, hemicellulose and lignin which are three main components of wood and grass were modeled at first. A molecular structure of each component was determined from that of its monomer, and a rate constant of each component was determined from both the conventional model and the pyrolysis curve from experiment. The pyrolysis process of wood and grass biomass was expressed by a summation of that of cellulose, hemicellulose and lignin calculated from the developed model. The content of each component in wood and grass was predicted from the ultimate analysis and the proximate analysis of wood and grass. By using above-mentioned new method, the pyrolysis process and the yields of total volatiles and tar of wood and grass biomass was predicted by only values of biomass properties and pyrolysis conditions. From a comparison between calculation and experimental results, the predicted pyrolysis process and yields of total volatiles and tar of various wood and grass biomass pyrolyzed under various conditions are in good agreement with the experimental ones, and we show the validity of the biomass-CPD model.