Direct dimethyether synthesis using revese shift assisted reforming

The direct dimethyl ether (DME) synthesis process from synthesis gas using reverse shift assisted reforming was studied. Since the direct DME synthesis can be optimized at about 1 of H₂/CO ratio, the refoming of methane has been an important issue to ajust the H2/CO ratio to about 1. In our direct DME process, the conventinal steam reforming is used. The synthesis gas with the excess hydrogen from the steam reformer was separated to adjust the H₂/CO ratios of the DME feed gas by a hydrogen membrane. The separated hydrogen was used to convert CO₂ to CO on the reverse shift reaction, and then the enriched CO gas was recycled and combined with the synthesis gas from the reformer. This process could increase the overall DME yield by mitigating CO₂. The bench plant of this DME process was installed and operated to show the high yield and low CO₂ production in the direct DME synthesis, as compared with the conventional direct DME process. This is an abstract of a paper presented at the 2008 AIChE Spring National Meeting (New Orleans, LA 4/6-10/2008).