【摘要】 采用热重分析方法研究谷壳和木屑及其NiO、MgO和CaO添加物在水蒸气气氛下的气化特性,采用两种常用的气固反应模型——收缩核模型和均相反应模型,计算得出反应动力学参数,同时用Ozawa法计算动力学参数,验证两种模型描述反应机理的适用性。在低温催化热解阶段,收缩核模型和均相模型基本适合此阶段反应机理,但在高温半焦催化气化阶段,不能简单地用收缩核和均相模型描述,此阶段反应机理不适合收缩核和均相模型。通过DTG曲线和Ozawa法计算出的表观活化能综合评价,3种催化剂在低温热解段催化活性大小顺序为:NiO>CaO>MgO,在高温气化段的催化活性大小顺序为NiO>MgO>CaO。更多还原

【Abstract】 Thermogravimetric analysis was selected to study gasification kinetics of rice husk(RH),saw dust(SD) and their blends adding NiO,MgO and CaO under steam atmosphere in the paper. Two common gas-solid reaction models(shrinking core model,SCM and homogeneous model,HM)and Ozawa method were used to calculate the kinetic parameters,and the two models were verified by Ozawa method for their applicability. In process of catalytic pyrolysis at lower temperature,the pyrolysis reaction mechanism was applicably described by SCM and HM,while in process of char catalytic gasification at higher temperature,the gasification reaction mechanism cannot be simply described by the two models,SCM and HM were not very suitable to the reaction mechanism of this process. The catalytic activity sequence of three catalysts were NiO>CaO>MgO in lower temperature catalytic pyrolysis process,and were NiO>MgO>CaO in higher temperature char catalytic gasification process assessed by DTG curve and apparent activation energy calculated by Ozawa method.更多还原