Abstract: When the Langmuir-Hinshelwood (L-H) kinetic model based on the theory of adsorption and desorption is used to describe the gasification reaction of coal char in the mixtures of H₂O and CO₂, there exist two controversial assumptions of separate active sites and common active sites. The gasification reaction characteristics of the Inner Mongolia coal char (NMJ) in the mixtures of H₂O and CO₂ were investigated using a tubular furnace experimental system at various reactant gas partial pressures and temperatures. The gasification reaction mechanisms of NMJ in the mixtures of H₂O and CO₂ were also investigated. The activation energies of NMJ-H₂O and NMJ-CO₂ were 214.78 kJ·mol^-1 and 145.96 kJ·mol^-1, respectively. H₂ and CO had obvious inhibition effects on the reaction of NMJ-H₂O and NMJ-CO₂, and the inhibition effects of CO increased with the decrease of reaction temperature. The reaction rate curves calculated by the L-H kinetic model fitted the experimental results very well. For the gasification reaction of NMJ in the mixtures of H₂O and CO₂, the L-H model based on the common active sites assumption fitted the experimental results very well under atmospheric pressure, indicating that common active sites assumption was more applicable to the gasification mechanisms of NMJ in the mixtures of H₂O and CO₂.

Key words: L-H model, char gasification, kinetics, fixed-bed

摘要： 应用基于吸附和脱附原理的Langmuir-Hinshelwood （L-H） 动力学模型来描述煤焦在H₂O和CO₂混合气氛下的气化反应时，存在单独活性位和相同活性位两个相互矛盾的假设。在管式炉实验装置内考察了在不同气化温度和气化剂分压的条件下，内蒙煤焦（NMJ）与H₂O和CO₂的气化反应特性，获得了NMJ-H₂O 和NMJ-CO₂反应的L-H动力学模型，同时考察了H₂、CO对煤焦气化反应的抑制作用，并探究了NMJ在H₂O和CO₂混合气氛下的气化反应机理。研究结果表明：NMJ-H₂O以及NMJ-CO₂反应的活化能分别为214.78 kJ·mol^-1和145.96 kJ·mol^-1。H₂对NMJ-H₂O以及CO对NMJ-CO₂的反应存在明显的抑制作用，且CO的抑制作用随反应温度的降低而愈加明显。基于L-H动力学模型计算得到的反应速率曲线与实验结果十分吻合。对于NMJ在H₂O和CO₂混合气氛下的气化反应，基于相同活性位假设的L-H模型的反应速率预测值与实验结果吻合，更加适用于NMJ在混合气氛下的气化反应机理。

关键词: L-H模型, 煤焦气化, 动力学, 固定床