作　　者： ; ; ; ; ;

机构地区： 上海应用技术学院化学与环境工程学院化学工程系

出　　处： 《石油学报（石油加工）》 2007年第1期20-27,共8页

摘　　要： 采用固态离子交换法制备了一系列不同氧化锑(Sb2O3)质量分数(0-30%)的锑改性HZSM-5分子筛,并以其为酸性组分与工业甲醇合成催化剂(XNC-98)组成双功能催化剂,在连续流动加压固定床反应器上考察了其对合成气直接制二甲醚反应的催化性能。结果表明,在温度260℃、压力4 MPa和原料气空速1500 ml/(g.h)的反应条件下,将经适量Sb2O3改性后HZSM-5分子筛组成的双功能催化剂与改性前HZSM-5分子筛组成的双功能催化剂相比,产物中二甲醚的选择性由55%显著提高到69%,而烃类和CO2副产物的选择性则分别由9.3%和32.4%降低至1%和28%以下。结合NH3-TPD酸性表征结果可知,Sb2O3改性显著提高二甲醚选择性的主要原因是其明显减少了HZSM-5分子筛强酸中心的数量。另外,还考察了反应条件如温度、压力和原料气空速对该双功能催化剂反应性能的影响。结果表明,较高的反应温度和空速导致较低的CO转化率和二甲醚选择性,故它们分别不能超过280℃和3000 ml/(g.h)。 A series of HZSM-5 zeolites modified with various mass fractions of antimony oxide ShoO3 （0-30%） were prepared by solid state ion exchange method, and then physically mixed with an industrial methanol synthesis catalyst （XNC-98） to form a series of hybrid catalysts CuO-ZnO-Al2O3 ＋Sb2O3/HZSM-5. The direct synthesis of dimethyl ether （DME） from syngas was carried out over the prepared hybrid catalysts under pressurized fixed-bed continuous flow conditions. The results indicated that over the CuO-ZnO-Al2O3＋Sb2O3/HZSM-5 hybrid catalysts with suitable amount of Sb2O3 the electivities of undesired byproducts hydrocarbons and CO2 were significantly decreased from 9. 3% and 32. 4% to less than 1% and 28%, respectively, and the selectivity for DME was enhanced greatly from 55% to 69% under temperature of 260℃, pressure of 4 MPa and gas hourly space velocity of 1500 ml/（g · h）, compared with that over the unmodified HZSM-5 hybrid catalysts. It was clear from the results of NH3-TPD characterization that the decrease in the formation of hydrocarbons and CO2 could be attributed to the significant decline in the amount of strong acid sites induced by Sb2O3 modification. In addition, the influences of the operating parameters, including the reaction temperature, pressure and space velocity of feed on the catalytic performance of the hybrid catalysts were also investigated. It was shown that at high reaction temperature and high gas hourly space velocity both lower CO conversion and lower DME selectivity were obtained, the suitable reaction temperature and gas hourly space velocity would be less than 280℃ and 3000 ml/（g·h）, respectively.

关 键 词： 分子筛 氧化锑 甲醇脱水 双功能催化剂 合成气 二甲醚

领　　域： [理学] [理学]