Synthesis of LPG via DME from syngas in two-stage reaction system

摘要

Synthesis of liquefied petroleum gas (LPG) via dimethyl ether (DME) from syngas was carried out in a two-stage reaction system, where syngas was transformed to DME in the first stage over the Cu-Zn-Al/ZSM-5 catalyst and then to hydrocarbons in the second stage over the Pd-Y catalyst. CO conversion and LPG selectivity were dominated by the first and second stage, respectively. CO conversion could be kept at a high level through the gradual increase of reaction temperature of the first stage, although there was a slight deactivation for the Cu-Zn-Al/ZSM-5 catalyst LPG selectivity in hydrocarbons was more than 75% due to the proper pore size of Y zeolite and the presence of hydrogen. Coke deposition on Y zeolite was the reason for the decrease of LPG selectivity, but fortunately the selectivity of LPG could be recovered to a great extent by coke burning.