Zn/HZSM-5催化剂上甲醇制芳烃反应条件研究

Study on reaction conditions for methanol to aromatics over Zn/HZSM-5

研究了在2%Zn/HZSM-5上甲醇制芳烃反应过程,考察了温度、质量空速、甲醇分压和水醇比对甲醇制芳烃反应的影响。结果表明,工艺条件对该反应的影响较大;低温下芳烃及BTX(苯、甲苯、二甲苯)选择性低,高温下,芳烃收率低;最佳的反应温度范围为400℃~420℃。甲醇空速对MTA反应影响也较大,低空速,影响进料的连续性,高空速,芳烃的收率及选择性降低,较佳的空速范围为0.7h^(-1)~1.0h(-1);甲醇分压增大,芳烃的收率变化较小,而催化剂的寿命受到影响,所以该反应低压即可满足需求;水醇比较小时,对MTA反应影响不大,但加入过多的水,芳烃的收率和选择性都会降低,当原料中水醇比不高于5/95时,芳烃的收率较高。

The conversion of methanol to aromatics（MTA） over the 2%Zn/HZSM-5 catalyst was studied. The effects of reaction temperature, weight hourly space velocity（WHSV）, partial pressure of methanol and the mass ratio of water to methanol on the MTA reaction were investigated. The results showed that reaction conditions had an important effect on MTA process. The selectivities of aromatics and BTX were low under low reaction temperature, while the yield of aromatics decreased under high reaction temperature,and the optimal reaction temperature range was 400-420℃. Low WHSV affected the continuity of the feed, while high WHSV would reduce the yield and selectivity of aromatics, and the optimal WHSV range was 0.7-1.0h（-1）. Increasing the partial pressure of methanol would not produce more aromatics but would shorten the life of catalyst, thus low pressure could be used for this reaction. When water-methanol mass ratio was low, it had little influence on the reaction, but adding too much water in methanol would lead to decreased yield and selectivity of aromatics, and the yield of aromatics was high when the water-methanol mass ratio was no more than 5/95.