采用浆态床反应器,研究了用完全液相法制备的Cu—zn—Al双功能催化剂上CO加氢直接合成二甲醚(DME)的反应动力学。按CO加氢先合成CH,OH,再由CH,OH脱水生成DME二步串联的反应机理,根据不同的中间产物及控制步骤分别建立了动力学模型,以反应物的平衡浓度代替逸度进行计算,最终选取的模型计算值和实验值吻合较好,说明采用L—H型动力学模型可以合理地描述催化剂表面的反应过程,模型参数计算结果表明,催化剂表面对CO2的弱吸附是该催化剂在浆态床中稳定性较好的主要原因之一。
The kinetics for one-step synthesis of dimethyl ether (DME) from syngas over a Cu-Zn-A1 bi-functional catalyst prepared by a complete liquid-phase preparation method was investigated in an agitated slurry reactor. Assuming the reaction includes two steps: the first step is methanol synthesis from syngas and the second step is methanol dehydration to DME, different kinetic models were established respectively according to different intermediates and rate determining steps. These models were calculated with the equilibrium concentration of the reactant in stead of fugacity. A good agreement between the experimental and the calculated results of the chosen model validates the Langmuir-Hinshelwood kinetic formation as an appropriate tool for describing the process on catalyst surface. The numerical values of parameters indicate that one of the reasons for better catalytic stability in the slurry reactor is weak adsorption of COs on the surface of the catalyst.