摘要
考察了反应温度、空速、压力、临氢条件以及催化剂的水热处理条件对液化石油气在ZSM 5分子筛催化剂上低温芳构化制取高辛烷值汽油反应性能的影响 .结果表明 ,反应温度和空速对催化剂的催化性能有明显影响 ,提高反应温度有利于提高芳烃的选择性 ,同时芳烃中的苯、甲苯和C10 + 芳烃含量增加 ;增大进料空速 ,催化剂的芳构化性能下降 ,芳烃中的重组分增加 ,二甲苯中对二甲苯含量增大 .催化剂的水热处理温度升高 ,其初始芳构化活性下降 ,而催化剂经过适当的水热处理和系统中氢气的存在均可提高催化剂催化芳构化反应的稳定性 .
The effects of reaction temperature, space velocity, pressure and hydrothermal treatment of the catalyst on the aromatization of liquefied petroleum gas (LPG) to high octane gasoline over ZSM-5 zeolite catalyst at low temperature were investigated. The catalyst exhibited high activity for aromatization when the reaction temperature was higher than 335 ℃, and showed high ability for olefin oligomerization when the temperature was lower than 300 ℃. Moreover, the selectivity for benzene, toluene and C 10+ aromatics increased with the reaction temperature. With the increase of the space velocity from 2 to 20 h -1, the selectivity for aromatics decreased from 62.1% to 12.3%. However, the selectivity for paraxylene increased even beyond the thermodynamic equilibrium, which is probably attributed to the shape selectivity caused by the quick coking in the channel of ZSM-5 zeolite. In addition, the presence of hydrogen in the reaction system is favorable for coking prohibition during the reaction and thus improved the catalyst stability. It was also found that the hydrothermal treatment of the ZSM-5 zeolite catalyst at a proper temperature changed the acidity distribution of the ZSM-5 catalyst and therefore the catalyst stability was enhanced.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2004年第3期199-204,共6页
关键词
ZSM—5分子筛
液化石油气
芳构化
汽油
水热处理
ZSM-5 zeolite, liquefied petroleum gas, aromatization, gasoline, hydrothermal treatment
