Research on Catalytic Gasification Characteristics and Reaction Kinetics of Rice Husk

The catalytic gasification properties and reaction kinetics of rice husk (RH) were studied by thermogravimetric analysis (TGA). The homogeneous model (HM) and shrinking core model (SCM) were used to simulate the gasification behaviors. The results indicated that magnesia and ferric oxide had obvious effects on the pyrolysis and gasification properties. They could increase the pyrolysis rate and gasification reactivity significantly. In the devolatilization stage, the reaction mechanism was apt to HM, whereas in the gasification stage, the reaction mechanism was apt to SCM. The gaseous products emitted during gasification were detected on-line with Fourier transform infrared spectroscopy (FTIR). The main gas products were H₂O, CO₂, CO, CH₄ and some hydrocarbons, etc. The low temperature peak of CO was mainly caused by the cracking and reforming of thermolabile carbonyl and ether groups. The high temperature peak of CO was predominately attributed to the Boudouard reaction between solid char and CO₂. CH₄ evolution covered over a wide temperature range of 300-700°C and was mainly due to the cracking of methoxyl groups. Moreover, the rupture of methylene groups could also contribute to the formation of CH₄.