05/00618 Tri-reforming of CH 4 using CO 2 for production of synthesis gas to dimethyl ether

Abstract

Steam reforming (SR) of dimethyl ether (DME) was investigated for the production of hydrogen forfuel cells. The activity of a series of solid acids for DME hydrolysis was investigated. The solid acid catalysts wereZSM-5 [Si/Al = 25, 38 and 50: denoted Z(Si/Al)] and acidic alumina (γ-Al2O3) with an acid strength order that was Z(25)>Z(38)>Z(50)>γ-Al2O3. Stronger acidity gave higher DME hydrolysis conversion. Physical mixtures containing a CuO-ZnO-Al2O3-ZrO2 catalyst and solid acid catalyst to couple DME hydrolysis and methanol SR wereused to examine the acidity effects on DME SR. DME SR activity strongly depended on the activity for DME hydrolysis. Z(25) was the best solid acid catalyst for DME SR and gave a DME conversion>90% [T = 240°C, n(H2O)/n(DME) = 3.5, space velocity = 1179 ml·(g cat)−1·h−1, and P = 0.1MPa]. The influences of the reaction temperature, space velocity and feed molar ratio were studied. Hydrogen production significantly depended ontemperature and space velocity. A bifunctional catalyst of CuO-ZnO-Al2O3-ZrO2 catalyst and ZSM-5 gave a high H2 production rate and CO2 selectivity.