工艺条件对甲醇脱水制二甲醚反应的影响

Influence of process conditions on methanol dehydration to dimethyl ether

以La改性氧化铝为催化剂,在模拟绝热固定床反应器中考察工艺条件对甲醇气相脱水制二甲醚反应的影响。结果表明,甲醇进料温度210℃时,甲醇脱水反应剧烈,绝热温升约130℃。催化剂床层热点温度低于380℃时,二甲醚选择性大于98%,过高温度产生大量副产物甲烷。反应压力对反应影响甚微。在甲醇进料温度240℃(热点温度370℃)、甲醇进料空速1.5 h-1和反应系统压力为50 k Pa条件下,甲醇转化率大于84%,二甲醚选择性大于98.5%,连续运转2 000 h,催化剂无明显失活迹象。

The process conditions of methanol dehydration to dimethyl ether（DME）on La / Al2 O3 catalyst was investigated in a simulated adiabatic fixed-bed reactor. The results indicated that methanol dehydration reaction was violent and the adiabatic temperature rise was about 130 ℃ when methanol inlet temperature was 210 ℃. The selectivity to DME was over 98% when the highest catalyst bed temperature was less than 380 ℃. Excessively high temperature resulted in the formation of a lot of byproduct methane. Reaction pres-sure had little influence on methanol dehydration reaction. Under the condition of methanol inlet temperature 240 ℃（ the highest catalyst bed temperature 370 ℃）,methanol space velocity 1. 5 h ^- 1 , reaction pressure 50 kPa,methanol conversion of over 84% and the selectivity to DME of more than 98. 5% were attained. The catalytic activity of La / Al2 O3 catalyst did not exhibit obvious change after running for 2 000 h.