An integrated air–POM syngas/dimethyl ether process from natural gas Original Research Article

A Cu-Zn-Al methanol catalyst combined with HZSM-5 was used for dimethyl ether (DME) synthesis from a syngas containing nitrogen, which was produced by air–partial oxidation of methane (air–POM). Air–POM occurred at 850 °C, 0.8 MPa, CH4/air/H2O/CO2 ratio of 1/2.4/0.8/0.4 over a Ni-based catalyst modified by magnesia and lanthanum oxide with 96% CH4 conversion and constantly gave syngas with a H2/CO ratio of 2/1 during a period of 450 h. The obtained N2-containing syngas was used directly for DME synthesis. About 90% CO per-pass conversion, 78% DME selectivity and 70% DME yield could be achieved during 450 h stability testing under the pressure of 5.0 MPa, the temperature of 240 °C and the space velocity of 1000 h−1.