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首页> 外文会议>The 4th Australia-China-Japan joint symposium on iron and steelmaking >Thermal Analysis Kinetics of Graphite-CO2/H20 Gasification
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Thermal Analysis Kinetics of Graphite-CO2/H20 Gasification

机译：石墨-CO2 / H20气化的热分析动力学

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The kinetics experiments of graphite gasification in CO2,H2O,and CO2 + H2O are carried out respectively by simultaneous thermal analysis techniques (Thermogravimetry-Derivative Thermogravimetry-Differential Scanning Calorimetry,TG-DTG-DSC),which can measure continuously the variation of mass and heat effect of sample under non-isothermal conditions.The combination of reaction kinetics and thermokinetics kinetics is used for the kinetic analysis.The experiments show that the entire process of graphite gasification can be divided into an exothermic slow gasification stage during the initial period and an endothermic fast gasification later.According to conservations of mass and energy,the analyses of non-isothermal kinetics arrive at the following conclusions.(1) In the process of graphite gasification,the exotherm of the initial stage is caused by the combined effects of the exothermic chemisorption and the endothermic chemical reaction.The graphite gasification reaction may be expressed by the series of chemisorption and chemical reaction,and the overall process is controlled by interface reaction via chemisorption.(2) In the fast gasification stage,the chemisorption step disappears.At this time,the gasification process can be expressed by a simple interface reaction.The Freeman-Carroll method was used to determine the kinetic parameters (activation energy E,pre-exponential factor A and reaction order n) for the process of graphite-CO2/H2O gasification.The analysis results are shown as follows:(1) The values of active energy decrease with increase of heating rate.At the same heating rate,there exists a kinetic compensation effect between the active energy and the pre-exponential factor.(2) In the process of graphite gasification by carbon dioxide,during slow gasification stage,the activation energy of adsorption and the activation energy of interface reaction via adsorption,respectively,in CO2 atmosphere are the highest,smaller in CO2 + H2O atmosphere,and the lowest in H2O atmosphere.The activation energy of interface reaction in the fast gasification stage is smaller than that in the slow gasification stage.
机译：通过同时热分析技术（热重-导数热重-差示扫描量热法，TG-DTG-DSC）分别进行石墨气化在CO2，H2O和CO2 + H2O中的动力学实验，可以连续测量质量和质量的变化。在非等温条件下样品的热效应。反应动力学和热动力学动力学的结合用于动力学分析。实验表明，石墨气化的整个过程可分为初始放热缓慢气化阶段和热解气化阶段。根据质量和能量守恒，对非等温动力学的分析得出以下结论：（1）在石墨气化过程中，初始放热是由石墨的综合作用引起的。放热化学吸附和吸热化学反应。 d。通过一系列化学吸附和化学反应，整个过程受化学吸附作用的界面反应控制。（2）在快速气化阶段，化学吸附步骤消失了。此时，气化过程可以用一个简单的界面表示用Freeman-Carroll方法确定了石墨-CO2 / H2O气化过程的动力学参数（活化能E，预指数因子A和反应阶数n），分析结果如下：（1 ）随着加热速率的增加，有功能量值减小。在相同的加热速率下，有功能量与预指数因子之间存在动力学补偿作用。（2）在二氧化碳气化石墨过程中缓慢的气化阶段，在CO2气氛中，吸附的活化能和通过吸附的界面反应的活化能分别最高，在CO2 + H2O气氛中较小，最低快速气化阶段的界面反应活化能比慢气化阶段的界面活化能小。

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