SAPO-11/HZSM-5对乙醇脱水制乙烯反应的催化性能

Catalytic Properties of SAPO-11/HZSM-5 for Ethanol Dehydration to Ethylene

测定HZSM-5与SAPO-11复合催化剂(SAPO-11/HZSM-5)对乙醇脱水制乙烯反应的催化性能,考察反应工艺条件;对比HZSM-5、SAPO-11和SAPO-11/HZSM-5催化乙醇脱水制乙烯反应性能;分析三种催化剂表面酸量及酸强度,以及对反应产物组成的影响。结果表明:SAPO-11/HZSM-5催化乙醇脱水制乙烯反应的适宜条件为:压力0.1 MPa,温度240℃,空速1.2 h-1,乙醇浓度99.7%;乙醇转化率、乙烯选择性分别为99.19%和98.77%;气相产物中乙烯含量达到98.92%,C3、C4组分含量分别为0.37%和0.40%,未检测到C5以上组分。SAPO-11/HZSM-5催化乙醇脱水制乙烯反应温度比HZSM-5、SAPO-11低60℃。适度增加催化剂表面弱酸量及强度,并使其具有相当比例的强酸量,有利于提高乙醇脱水制乙烯反应活性和乙烯选择性。

Catalytic performance of the mixed catalysts（SAPO-11/HZSM-5） used for ethanol dehydration to ethylene was studied,and the effects of dehydration conditions were investigated.The catalytic performances of HZSM-5,SAPO-11 and SAPO-11/HZSM-5 for ethanol dehydration to ethylene were compared,and the effects of the surface acidic amount and strength of above three catalysts on the production compositions were analyzed.Results show that,when using SAPO-11/HZSM-5,the optimum conditions for ethanol dehydration to ethylene are pressure 0.1 MPa,reaction temperature 240℃,space velocity 1.2 h-1 and concentration of ethanol feeding 99.7%（wt）.Under above conditions,the ethanol conversion ratio and the selectivity for ethylene can reach 99.19% and 98.77%,respectively,and the content of ethylene is 98.92% in gas production.Meanwhile,the contents of C3 and C4 are 0.37% and 0.40%,respectively,and there are no other high hydrocarbons.Using SAPO-11/HZSM-5,the ethanol dehydration temperature is 60℃ lower than that of HZSM-5 and SAPO-11.It was found that improving the surface weak acidic amount and strength with feasible surface strong acidic strength is propitious to increase the reaction performance and selectivity for ethylene of the catalysts.