Effect of the hybrid catalysts preparation method upon direct synthesis of dimethyl ether from synthesis gas

Direct synthesis of DME from synthesis gas attains more attention recently due to higher conversion and lower cost in comparison to dehydration of the methanol. In this work Synthesis gas To Dimethylether (STD) conversion was examined on various hybrid catalysts prepared by seven different methods. These catalysts had the same general form as CuO/ZnO/Al2O3 with theoretical weight ratio 31/16/53, respectively. A novel preparation method for hybrid catalyst namely sol–gel impregnation has also been developed which showed better performance in comparison with the other methods. Also, in order to find out the effect of various alumina contents at a fixed CuO/ZnO ratio on the performance of the hybrid catalyst, a series of catalysts with different contents of alumina have been prepared by sol–gel impregnation method. The optimum weight ratio for CuO/ZnO/Al2O3 catalyst has been found to be about 2:1:5, respectively. These catalysts characterized by TPR, XRD, XRF, BET, TGA, N2O absorption. The catalysts performance were tested at 240 °C, 40 bar and space velocity 1000 ml/gcat.h, with the inlet gas composition H2/CO/N2 = 64/32/4 in a micro slurry reactor.