Gas Release Characteristics of Various Species in Pyrolysis of Wood and Grass Biomass

Abstract

This paper presents a new method for predicting the gas release characteristics of various species in pyrolysis of wood and grass biomass. The pyrolysis experiment of various biomass samples were carried out, and the gas release process in pyrolysis was measured. Large amount of CO₂ and CO were released at first. CH₄ was subsequently released. Additional CO was released at more than 700°C in the pyrolysis of lignin and lignin-rich biomass. Finally, H₂ release was increased. This gas release Characteristics indicate that the pyrolysis mechanism of biomass was almost same with that of coal. Based on these experimental results, biomass-CPD model was modified to divide the reactions of intact bridge, side chain and aromatic cluster for predicting the gas release process of various species. In the first reaction, H₂O, CO and CO₂ were released from intact bridge and side chain. Next reaction was the release of CH₄ from intact bridge and side chain. Further CO release from intact bridge and side chain occurred at high temperature only in lignin pyrolysis. Finally, H₂ was released from intact bridge, side chain and aromatic cluster. Kinetic parameters of those reactions were determined from values of the conventional pyrolysis model both of coal and biomass. Consequently, the gas release process of various species was well predicted by using above mentioned new biomass-CPD model.