【作者】 朱向学；

【导师】 徐龙伢；

【作者基本信息】 中国科学院研究生院（大连化学物理研究所） ， 工业催化， 2005， 博士

【摘要】 C₄C₅烯烃催化裂解是增产丙烯的有效方法之一，论文以丁烯为反应物，对该过程中催化剂的制备及反应条件的优化进行了系统的研究。 首先计算了丁烯以不同途径转化各反应的热力学平衡常数及丁烯平衡转化率，讨论了温度和压力对各反应平衡的影响，确定了提高目的产物丙烯／乙烯选择性的可能性与可行性，为催化剂筛选及反应条件的优化提供了理论指导。 系统研究了不同结构分子筛的反应性能，表明择形性与稳定性均较佳的为ZSM-5和MCM-22；小孔分子筛对丙烯／乙烯有最优的择形性能；大孔、小孔及一维孔道结构分子筛稳定性均较差。高硅ZSM-5较弱的酸性可抑制氢转移及芳构化副反应的发生，大大提高丙烯选择性及催化剂稳定性；小晶粒分子筛显示出更好的稳定性。首次将K改性及水热处理方法引入C₄烯烃裂解制丙烯催化剂的制备过程中，发现适宜的水热处理及K改性均可效抑制氢转移及芳构化副反应的发生，提高丙烯选择性，并考察了反应条件对性能较佳的改性催化剂性能的影响，反应结果与文献中报导的结果相当（45～55％丙烯选择性，35～39％收率）。 首次将MCM-22用于本反应中，发现反应初期其性能存在一个突变：转化率快速下降，丙烯选择性大幅上升一归因于其超笼的快速失活；而后，在反应的平台期，给出与高硅ZSM-5相当的丙烯+乙烯选择性（～66％）。以不同产物产率对原料转化率作图，分析了不同产物生成机理，提出了C₄烯烃转化的反应网络，为认识反应本质及有效通过各种手段抑制副反应发生提供了依据。首次发现氟硅酸铵（AHFS）处理是制备高硅MCM-22的有效方法，制备样品硅铝比可高达160且保持较好结晶度，大大拓宽了直接合成MCM-22硅铝比范围（20～50）。适当的AHFS处理或水热处理可明显提高其在C₄裂解反应中的稳定性。 采用较低反应温度有利于提高催化剂的稳定性，所用的分子筛催化剂有较好的再生使用性能。更多还原

【Abstract】 Catalysts design and reaction conditions optimization were investigated systemically for the process of C₄ alkene catalytic cracking, an effective way enhancing propene production.The equilibrium constant of each reaction for butene conversion, along with the effects of temperature and pressure on each reaction, were calculated thermodynamically. According to that, the possibility and feasibility to increase the selectivity of propene in C4 alkene cracking were discussed. These results provided guidance for catalysts design and reaction conditions optimization in C₄ alkene cracking.The catalytic performance of the zeolites with various structures and pore diameters were tested in the process and it was found that: ZSM-5 and MCM-22 exhibited better shape-selectivity for propene plus ethene and the best stability among the zeolites studied; the small-pore SAPO-34 zeolite was the most "shape-selective" for propene and ethene; the large-pore zeolites, the small-pore zeolites and the zeolites with one-dimensional structure all exhibited poor stability due to the covering of the acid sites or channel blockage by the coke.On ZSM-5 zeolite with higher Si/Al₂ ratio, higher selectivities of propene/ethene and better stability were gained, resulted from its lower acidity suppressing the secondary reaction of the alkenes and the coking reaction. High silica ZSM-5 with smaller particles gave better stability in the process. The means modifying the ZSM-5 zeolite by K addition or steaming treatment were introduced to the process of catalyst preparation for C₄ alkene cracking. The catalysts modified to a更多还原