丙烷在Mo/HZSM-5上的芳构化 Ⅰ.催化剂制备条件及反应性能间的关系

Propane aromatization over Mo/HZSM-5 Ⅰ. Relationship between catalyst preparation and reactive performance

采用浸渍法、机械混合法和水热法制备Ｍｏ／ＨＺＳＭ－５分子筛催化剂，考察了Ｍｏ含量、催化剂预处理气氛、在线反应时间及催化剂再生对丙烷芳构化反应的影响。结果采用水热法制备的催化剂能显著提高丙烷转化率和芳烃选择性，在５５０℃、６００ｈ－１条件下，转化率和选择性分别达到８９．７％、７８．６％；该催化剂具有较高的活性稳定性，经２４ｈ反应后，仍能保持较高的芳构化活性。对Ｍｏ含量影响的考察表明，浸渍法和水热法制备的催化剂分别在ｗ（Ｍｏ）＝２％、６％时芳构化活性最高。

Three Mo/HZSM 5 catalysts used for propane aromatization were prepared by means of impregnation, mechanical mixing and hydrothermal method. The influnces of Mo content, pretreatment atmosphere, time on stream, and catalyst regeneration were examined on the reaction . The catalytic performance of the catalyst made by hydrothermal treatment was much better than by the other two ways methads. For example, conversion propane and selectivity to aromatics over the hydrothermally treated catalyst were respectively up to 89.17% and 78.56% at 550℃ and 600h -1 (GHSV). After reaction for 24h, the hydrothermally treated catalyst could maintain higher activity for aromatizatian, showing that its activity was highly stable. Strong interaction between Mo and acidic centers within pores enhanced thermal stability of the catalyst and inhibited Mo loss, therefore the catalyst possessed better resistance to coking than other catalysts used in this study. The catalysts prepared by impregnation and hydrothermal treatment gave maximum activities when their Mo contents were 2% and 6%(mass), respectively.