K/ZSM-5的正己烷催化裂解性能

n-Hexane catalytic cracking over K/ZSM-5

采用浸渍法制备了一系列不同K载量的K/ZSM-5催化剂,在小型固定床实验装置上考察了催化剂的正己烷催化裂解活性及产物分布的影响规律。结果表明,碱金属K改性可以降低ZSM-5分子筛的酸性,从而大大提高了丙烯的选择性,使得丙烯/乙烯质量比从0.59提高至3.22,同时也降低了甲烷、芳烃等副产物的选择性。另外,还考察了反应条件对1.0 K/ZSM-5催化剂反应性能的影响,当反应温度650℃,空速3 h-1时,双烯收率大于48%,丙烯/乙烯质量比达到1.30。

Catalytic cracking of n-hexane was carried out in a small fixed-bed reactor over potassium modified ZSM-5 catalysts. The result shows that modification of potassium can decrease the acidity of ZSM-5molecular sieve,thus increase selectivity of propylene,and improve ratio of propylene to ethylene from0. 59 to 3. 22,while decrease selectivity of by-product of methane,ethylene and aromatics. Meanwhile,the influence of reaction conditions on the reaction performance of 1. 0 K/ZSM-5 catalyst was also investigated. The yields of ethylene and propylene were more than 48%,and the ratio of propylene to ethylene reached 1. 30 under the reaction condition of 650 ℃,WHSV 3 h^(-1).