摘要
采用红外光谱、X射线衍射、扫描电子显微镜、电感耦合等离子体焰炬(ICP)元素分析、氮低温吸附和吡啶红外等表征手段对合成的不同硅铝比ZSM-5催化剂进行了表征,并在微分反应器中考察了沸石硅铝比对甲醇制丙烯反应中丙烯收率和丙烯-乙烯质量比(P/E)的影响。结果表明,随着硅铝比增加,丙烯收率先升后降而乙烯收率则持续下降。机理分析表明,丙烯的稳定性低于乙烯是导致产物丙烯收率随催化剂酸性降低先升后降而乙烯收率连续下降的原因,是影响P/E比的关键因素。硅铝比为120的ZSM-5催化剂具有质量分率34.3%的丙烯收率,丙烯-乙烯质量比达到4.1,若要进一步提高丙烯收率和P/E比,需从其他方面(如扩散性能改善)对催化剂进行改性。
The as-synthesized ZSM-5 zeolites with different Si/AI ratios and the similar particle sizes were characterized by infrared （IR）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, inductively coupled plasma （ICP）, N2-adsorption and Py-IR techniques. The methanol conversion reactions over these catalysts were carried out in a micro-reactor and the influence of Si/Al ratio in ZSM-5 on the propylene yields and the ratios of propylene to ethylene （P/E） were investigated. It was showed that the yield of ethylene decreased but the propylene yield increased first and then decreased as the Si/Al increased. And the kinetics analysis showed that the less stability of propylene than ethylene was the determinant for such phenomena. The propylene mass yield of 34.3% and P/E ratio of 4.1 were obtained over ZSM-5 with Si/Al ratio of 120. Other kind of modification on ZSM-5 was needed for the purpose of further increasing propylene yields and P/E ratios.
出处
《化学反应工程与工艺》
EI
CAS
CSCD
北大核心
2007年第5期385-390,共6页
Chemical Reaction Engineering and Technology
基金
国家重点基础研究规划(973计划
2003CB615801)
