Catalytic partial oxidation of methane with air to produce syngas and dimethyl ether synthesis from the syngas containing N_2

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.