摘要
在固定床微反装置上,采用ZSM-5分子筛催化剂,考察了不同条件下乙烯的低聚反应。结果表明,适宜的条件可以抑制副反应,提高产物中丙烯与丁烯的选择性。随反应时间的延长,催化剂因积炭而失活,乙烯转化率由初始的96.2%降至6 h后的41.1%,丙烯和丁烯选择性增加。提高乙烯空速可有效抑制氢转移反应从而提高烯烃选择性,根据不同转化率对应的产物分布,得到了ZSM-5催化剂上乙烯低聚的反应路径。乙烯转化率随反应温度的升高先增加后降低,500℃时达到最大值为88.0%,主要产物LPG组分中烷烃居多。提高反应压力有利于低聚反应进行,可以显著提高乙烯转化率,但不利于生成丙烯和丁烯。
Oligomerization of ethene over ZSM-5 catalyst was investigated on a fixed bed micro-reactor. The catalytic performance of HZSM-5 zeolite was markedly affected by the reaction conditions. Moderate reaction conditions can suppress secondary reactions and enhance the production of propene and butene. A slow deactivation accompanied by changes in the product distributions was observed along with the reaction time, which can be attributed to the coke deposition in the HZSM-5 pores during reaction. The conversion of ethene decreased gradually from initial 96.2% to 41.1% after 6 h reaction, whereas the selectivity to propene and butene was increased during this period. Hydrogen transfer reaction was restrained at high space velocity, resulting in an increase of the selectivity to olefins. On the basis of the product distributions under different ethene conversions, a reaction pathway for ethene oligomerization was proposed. With the increase of the reaction temperature, ethene conversion increased first, reached a maximum value of 88.0% at 500℃, and then dropped ; paraffins are dominated in the main product LPG. Raising the pressure of reaction system could promote the oligomerization of ethene, which was beneficial to ethene conversion, but unfavorable for yielding propene or butene.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2009年第5期560-566,共7页
Journal of Fuel Chemistry and Technology
关键词
乙烯
丙烯
干气
低聚
ZSM-5
ethene
propene
dry gas
oligomerization
ZSM-5
