炼厂混合C4烃催化裂解制低碳烯烃催化剂及工艺条件的研究

【作者】 王睿；

【导师】 陈立宇；

【作者基本信息】 西北大学 ， 化学工程， 2010， 硕士

【摘要】 炼厂混合C4烃类催化裂解是增产丙烯的有效方法之一,本论文以炼厂混合C4烃为原料,对催化剂改性、反应工艺条件优化及反应机理的进行了系统研究。首先综合丁烯二聚-裂解、异丁烷和丁烯的烷基化及2-丁烯与乙烯的歧化机理提出混合C4烃催化裂解过程的主要反应途径,并提出混合C4烃催化裂解过程中主反应和主要的副反应,对主副反应进行热力学分析,为催化剂的筛选和工艺条件的优化提供理论指导。本实验研究HZSM-5分子筛硅铝比对混合C4烃裂解性能的影响,筛选出最佳的分子筛硅铝比为200。以硅铝比为200的HZSM-5分子筛为载体,负载不同改性物质制备了一系列催化剂,从中筛选出具有优良催化活性的La-HZSM-5和Ce-HZSM-5分子筛催化剂,并研究了改性物质含量对裂解性能的影响,La-HZSM-5和Ce-HZSM-5分子筛最佳的改性活性成分含量为0.099g/g-cat和0.051g/g-cat。以La-HZSM-5和Ce-HZSM-5分子筛作为工艺条件优化的催化剂,考察了进料流率、反应温度和水烃比(m)对混合C4烃裂解性能的影响。得到最优的工艺条件为：进料流率40ml/min、反应温度480℃和水烃比0.3。在该最佳工艺条件下,Ce-HZSM-5分子筛的裂解性能略优于La-HZSM-5分子筛,其转化率和丙烯的选择性可达67.15%和72.44%,P／E=7.1。催化剂具有较长的使用寿命,其失活主要是表面积碳覆盖活性中心所致。催化剂的再生采用空气二段烧碳法,催化剂再生温度分别为400℃和550℃。再生后的催化剂基本保持了新鲜催化剂的催化活性。更多还原

【Abstract】 Refinery catalytic cracking of mixed C4 hydrocarbons was one of the effective ways to increase propylene yield. This thesis with the refinery mixed C4 hydrocarbon as raw material, studied systematically the modified catalysts, the optimization of reaction conditions and the reaction mechanism.Based on the mechanism of butene dimerization-cracking, isobutane and butene alkylation and 2-butene and ethylene disproportionation, we proposed the main reaction paths of mixed C4 hydrocarbon catalytic cracking process, as well as the main reactions and the major side reations, and thermodynamic analysis of theirs. Thus providing theoretical guidance to screen catalyst and optimize the process conditions.In this experiment, we studied the influence of HZSM-5 sieve Si-Al ratio on mixed C4 hydrocarbon cracking properties, and selected the best Si-Al ratio was 200. With Si-Al ratio 200 of HZSM-5 as the carrier, a series of different modified catalysts were prepared, selected excellent catalytic activity of La-HZSM-5 and Ce-HZSM-5 zeolite catalyst, and studied the influence of modified materials on the performance of the modified catalyst, La-HZSM-5 and Ce-HZSM-5 molecular modification of the best material content were 0.099g/g·cat and 0.051g/g·cat.With La-HZSM-5 and Ce-HZSM-5 molecular sieve as a catalyst optimized process conditions, we studied the influence of feed flow rate investigated, reaction temperature and water-hydrocarbon ratio(m) on mixed C4 hydrocarbon cracking performance. The optimal conditions were:feed flow rate 40ml/min, reaction temperature 480℃and water-hydrocarbon ratio 0.3. Under the optimum conditions, Ce-HZSM-5 molecular sieve cracking performance is superior to La-HZSM-5, conversion and propylene selectivity of 67.15% and 72.44%, P/E =7.1.Catalyst had a longer service life, its inactivation was mainly due to carbon covering the active site. The catalyst regeneration temperatures were 400℃and 550℃. Regenerated catalyst still remained fresh catalyst activity.更多还原