双功能混合催化剂上含氮合成气直接制取二甲醚的宏观动力学

Global Kinetics of Direct Synthesis of Dimethyl Ether from Syngas Containing N_2 over Bifunctional Mixed Catalyst

在温度220～260°C,压力5MPa,转筐转速2600r/min,空速1000～2000mL/(g·h)条件下,建立了工业级双功能混合催化剂上含氮合成气直接制二甲醚的宏观动力学模型,并获得了模型参数。统计检验和残差分析表明模型可靠。根据获得的宏观动力学及本征动力学的模拟计算,比较了两模型下温度及含氮量对反应的影响。由于含氮量影响反应组分的分压,进而影响CO的转化率,还通过影响反应组分在催化剂颗粒内的内扩散来影响产物的选择性,但总的结果是内扩散的存在减弱了催化剂的协同效应。

The global kinetics of direct synthesis of dimethyl ether from syngas over bifunctional catalyst mixed by methanol synthesis catalyst and dehydration catalyst was obtained. The experiment was ex-(ecuted) at 220~260 °C, 5 MPa, 1 000~2 000 mL/(g·h) and the rotation of the basket was 2 600 r/min. The model is reliable and adequately describes the experimental results. The effects of temperature and content of N_2 were compared with the calculated results based on the intrinsic kinetics or global kinetics we obtained. The synergy effect of the catalyst decreased because of the (internal) diffusion in the big size bifuctional catalyst.