Isothermal chemical conversion of biomass pellets under the atmospheres of Ar, CO₂ and O₂ were conducted in this study to explore the effects of atmosphere and temperature on the gaseous releasing process and kinetics, and the structure of the solid char/ash products. Results showed that the gas production was promoted while the solid yield was decreased with the raising temperature. The CO₂ reaction with char during gasification process mainly happened after 800 °C that the CO formation lasted for a longer time than pyrolysis. The surface area of char under CO₂ atmosphere was increased to 215.57 m²/g with the increased temperature to 800 °C, but it was sharply reduced to 5.10 m²/g when the temperature further raising to 900 °C due to the destroyed carbon skeleton. The CO₂ formation was largely promoted with a low activation energy of 11.98 kJ/mol during O₂ oxidation process. Compared with the crystal structure of solid residues obtained under Ar and CO₂ atmospheres, O₂ oxidation process resulted in more complex crystal peaks with the main compositions of SiO₂, K₂SO₄, and CaO. This study should be helpful to further understand the thermal conversion of biomass in a complex reaction atmosphere.

本研究在Ar、CO ₂和O ₂气氛下进行生物质颗粒的等温化学转化，以探索气氛和温度对气体释放过程和动力学以及固体炭/灰产物结构的影响。结果表明，随着温度的升高，产气量增加，而固体收率降低。气化过程中CO ₂与焦炭的反应主要发生在800℃之后，CO的形成持续时间比热解时间长。随着温度升高到 800 °C，CO ₂气氛下炭的表面积增加到 215.57 m ² /g，但急剧减少到 5.10 m ²/g 当温度进一步升高到 900 °C 时，由于碳骨架被破坏。在O ₂氧化过程中，CO _{2 的}形成在11.98 kJ/mol 的低活化能下得到了极大的促进。与在Ar和CO ₂气氛下获得的固体残留物的晶体结构相比，O ₂氧化过程产生了更复杂的晶体峰，其主要成分为SiO ₂、K ₂ SO ₄和CaO。该研究有助于进一步了解生物质在复杂反应气氛中的热转化。