An Integrated Process Of Air-POM Syngas/Dimethyl Ether

Dimethyl Ether (DME) is not only an important chemicals, but also an ideal substitute for diesel or liquefied petroleum gas. Furthermore, DME is also an important chemical feedstock for the preparation of light alkenes. So, the application prospect of DME becomes broader and broader. In recent years, DME synthesis from synthesis gas has attracted much attention in research fields and industrial fields for its low cost and low energy consumption.DME synthesis from the synthesis gases which was produced by four different syngas production processes respectively, has been studied in this paper. The single-step synthesis of DME from the cheap syngas containing N2, which was produced by air-partial oxidation of methane, has been investigated in details in order to decrease the production cost of DME.The single-step Syngas-to-Dimethyl ether process was investigated in a fix-bed reactor. The results illustrated that the consumption of natural gas per ton DME was less in the CH4-Air-H2O-CO2 process than it in other syngas production process. Although the DME synthesis from the syngas containing Nj could achieve higher than 90% CO single pass conversion, the negative impact of excessive N2 amount should be considered.Then the single-step Syngas-to-Dimethyl ether process was carried out in a fix-bed reactor, a slurry bed reactor and an integrated reactor which involves a slurry and a fix bed reactor. The results demonstrated that the integrated reactor is the optimum reactor for DME synthesis, in which the high per-pass CO conversion was obtained, and the formation of hot spot could be avoided simultaneously.The deactivation study indicated that the main reason for DME catalyst deactivation is the Cu sintering, which results in the decrease of specific surface area and dispersion of the active Cu species. Moreover, the results showed that it is useful for inhibiting the Cu sintering to synthesize DME using the syngas containing N2.In DME synthesis, there exists Cu0/Cu+ redox recycle and the DME synthesis mechanism is put forward.