甲烷空气催化部分氧化制合成气与含氮合成气制二甲醚的研究

采用常规浸渍法制备了经镧和镁改性的镍基催化剂 ,以铜锌铝甲醇合成催化剂和HZSM 5分子筛通过机械混合制备了二甲醚合成催化剂。采用固定床流动反应色谱装置研究了甲烷空气催化部分氧化制合成气的催化性能 ,同时开展了以含氮合成气制备二甲醚的研究。结果说明 ,镍基催化剂对甲烷空气部分氧化制合成气在常压下具有高的转化率 ,随压力升高 ,转化率明显下降 ,并且催化剂严重积炭 ,通过向反应体系添加H2 O和CO2 可以提高加压条件下的CH4转化率并抑制催化剂积炭 ,还可获得n(H2 ) /n(CO)接近 2的合成气 ,满足合成二甲醚的要求。采用含氮合成气制备二甲醚 ,在压力 7.0MPa ,空速 10 0 0h-1条件下 ,催化剂连续使用 2 0 0h性能基本稳定 ,CO转化率在 93%左右 ,DME选择性在 77%左右 ,DME收率在 72 %左右

Catalytic partial oxidation of methane with air to produce syngas and dimethyl ether synthesis from the syngas containing N2

The conventional impregnation method was used to prepare Ni based catalyst modified by La and Mg and the mechanical mixing method was used to prepare the bifunctional catalyst for DME synthesis by using the Cu based catalyst and HZSM 5 zeolite. The catalytic performance for the partial oxidation of methane with air (CPO) was investigated. The results indicated that Ni based catalyst modified by La and Mg had high CH_4 conversion at atmosphere pressure for the CPO and the CH_4 conversion decreased as the pressure increased. The carbon deposition was serious when the reaction was performed under high pressure. Adding H_2O and CO_2 could improve the CH_4 conversion and inhibit the carbon deposition. The obtained syngas, with the ratio of H_2/CO close to 2, could meet the DME synthesis need. The DME synthesis from the syngas containing N_2 was studied as well. When the reaction was performed under pressure of 7.0MPa, space velocity of 1000h -1 , the catalyst could keep high activity during 200h life test. The CO conversion, the DME selectivity and the DME yield could achieve 93%, 77% and 72% respectively. The high one pass CO conversion means that the feedstock gases don't need to be recycled.