HZSM-5分子筛与铜基的复合催化剂上合成气制二甲醚

以ＨＺＳＭ－５分子筛与铜基甲醇合成催化剂组成复合催化剂用于从合成气制二甲醚，以ＨＺＳＭ－分子筛替代γ－Ａｌ２Ｏ３作脱水催化剂可降低复合催化剂的活性温度。在２５０～２６０℃，ＨＺＳＭ－５分子筛复合的催化剂，其ＤＭＥ选择性、时空产率均高于γ－Ａｌ２Ｏ３。甲醇合成催化剂与ＨＺＳＭ－５分子筛配比为３∶２时，ＣＯ转化率、ＤＭＥ时空产率较高。不同甲醇合成催化剂只影响复合催化剂的ＣＯ转化率，不影响ＤＭＥ选择性。不同硅铝比的ＨＺＳＭ－５分子筛对复合催化剂的ＤＭＥ选择性影响显著，当硅铝比从３２．７９增至５２．０９，ＤＭＥ选择性增大，ＭｅＯＨ、ＣＯ２选择性下降；当硅铝比从５２．０９增至７０．７０时，ＤＭＥ、ＭｅＯＨ、ＣＯ２选择性几乎不变。

A hybrid catalyst for DME synthesis from syngas with HZSM 5 as dehydration catalyst

A hybrid catalyst, composed of a Cu base methanol synthesis catalyst and a HZSM 5 zeolite, has been studied for dimethyl ether(DME) synthesis from syngas.The substitution of HZSM 5 for γ Al 2O 3 for dehydration results in a decrease of operating temperature of the hybrid catalyst.At 250～260℃, both the selectivity to and space time yield (STY) of DME with the hybrid catalyst using HZSM 5 are higher than using γ Al 2O 3. A hybrid catalyst with a ratio of Cu base catalyst to HZSM 5 of 3∶2 gives higher CO conversion and DME STY. Different methanol synthesis catalysts give different conversions of CO for the hybrid catalyst without any effect on the selectivity to DME. HZSM 5 zeolites with different Si/Al ratios exert significant effects on product selectivity.As the Si/Al ratio increases from 32.79 to 52.09, the selectivity to DME increases while the selectivities to MeOH and CO 2 decrease.A further increase of the Si/Al ratio from 52.09 to 70.70 yields no change in product selectivities.