金属组分负载量对Cu-Mn-Zn/Y直接合成二甲醚催化剂的影响

The Cu-Mn-Zn/Y catalysts with the different content of metallic component were prepared through a coprecipitation impregnation method, and used for the synthesis of dimethyl ether (DME) from synthesis gas in a fixed-bed reactor. The optimum content of metallic component loading on per gram zeolite Y was about 30mmol, and the conversion of CO and the selectivity of DME were 65.6% and 67.0% under 2.0MPa, 245℃ and 1500h－1. XRD, BET and TPD of H2, CO and NH3 results showed that, with the metal content increasing from 20mmol to 30mmol, the dispersion of all metallic component became better, the adsorption ability of H2 and CO also increased, but the surface area and the acidity of these catalysts did not changed. As the metal content up to 35mmol, the accumulated copper and micro-structural changes occurred, the surface area of the catalysts and the adsorption ability of H2 and CO decreased rapidly, the number and strength of acid sites also decreased. Consequently, the Cu-Mn-Zn/zeolite-Y catalyst with 30mmol metal loading exhibited the best catalytic performance for direct synthesis of DME was duo to the favorable adsorption ability of H2 and CO.