【作者】 王星星；

【导师】 陈长林；

【作者基本信息】 南京工业大学 ， 化学工程， 2006， 硕士

【摘要】 我国催化裂化汽油(FCC)比例高达80%,而FCC汽油烯烃体积分数在50%左右,已经远远超出了国家和国际标准。可以采用改进催化裂化技术、醚化和加氢精制等技术来降低FCC汽油烯烃含量,但这些方法降低烯烃含量的幅度很有限,或者使得汽油辛烷值降低。利用汽油非临氢芳构化技术把汽油中烯烃转化为辛烷值更高的芳烃可以达到大幅度降低烯烃和保持辛烷值不降低甚至有所提高的目的,同时节省了能源,降低了设备要求,最终减少了生产成本。本文采用共浸渍法制备了Zn、P和Ga改性的HZSM-5催化剂。同时利用X射线衍射(XRD)、N2吸附比表面积测定(BET)、氨程序升温脱附(NH3-TPD)、傅立叶红外光谱(FT-IR)、热重(TG)等方法对水热处理前后改性催化剂的晶相结构、比表面积、表面酸性和反应积炭行为进行表征。结果表明,水热处理总体上没有破坏HZSM-5的骨架结构,降低了ZnPGa/HZSM-5催化剂的比表面积、总酸量和酸强度,抑制了ZnPGa/HZSM-5催化剂上正庚烷芳构化反应过程中的积炭。催化剂上正庚烷芳构化反应性能评价结果表明Zn的引入既抑制了HZSM-5上正庚烷的裂解又促进了芳构化反应的进行,最佳Zn负载量为2%;第二组元P的引入能阻止Zn的流失,同时阻碍了芳构化反应过程中大分子物质的生成,减少了催化剂表面积炭,从而提高了催化剂芳构化性能稳定性,最佳P负载量为0.2%;第三组分Ga的引入不仅能促进正庚烷转化和芳构化,还能抑制中间产物氢解,增加液体产物收率,最佳Ga负载量为0.2%。水热处理降低了ZnPGa/HZSM-5上正庚烷芳构化反应的初活性,但提高了液体收率和稳定性。ZnPGa/HZSM-5催化剂具有良好的正庚烷芳构化反应稳定性。在反应温度400 oC,反应压力0.1MPa,WHSV为2h-1的工艺条件下,ZnPGa/HZSM-5催化剂上正庚烷芳构化反应120 h时间内的液体收率、正庚烷转化率、芳烃选择性及液相产物中芳烃含量分别稳定在55%,70%,15%,20%左右。FCC汽油中具有代表性的烯烃1-己烯在Zn、P和Ga的负载量分别为2%、0.2%和0.2%的最佳改性HZSM-5上的芳构化反应结果表明,在相同反应条件下,1-己烯比正庚烷更容易芳构化。水热处理降低了ZnPGa/HZSM-5上1-己烯芳构更多还原

【Abstract】 The proportion of fluid catalytic cracking(FCC) gasoline is as high as 80 % in our country. The fraction of olefins in FCC gasoline is around 50 v% which has far exceeded national and international criterion. Olefins content in FCC gasoline can be reduced by promoting FCC technology, etherification, hydrogenation and so on. But these methods can not reduce olefins content to a great extent, or they will lower gasoline octane number. Converting olefins in FCC gasoline into aromatics with more octane number than olefins by aromatization technology without hydrogen flow can greatly reduce olefins content, keep octane number even increase it, while it can save energy, reduce equipment demand and bring down production cost finally.In this thesis, Zn, P and Ga modified HZSM-5 catalysts were prepared by co-impregnation method. The structure, surface area, acid properties and coke deposition of modified catalysts with and without hydrothermal treatment were characterized by x-ray powder diffraction(XRD), nitrogen-adsorption surface area measurement(BET), NH3 temperature-programmed-desorption(NH3-TPD), pyridine FT-IR and thermogravimetry(TG). The results showed that hydrothermal treatment did not destroy HZSM-5 framework structure while it decreased surface area, total acid amount, strong acid sites of ZnPGa/HZSM-5 catalyst and the coke deposition on ZnPGa/HZSM-5 catalyst for n-heptane aromatization.The evaluation result of n-heptane aromatization performance over various catalysts showed that introduction of Zn not only restrained n-heptane cracking but also accelerated its aromatization. The optimal Zn loading amount is 2 wt%. Introduction of the second element P could prevent Zn from flowing away while it restricted production of big molecules during aromatization process and decreased coke deposit on the surface of the catalyst so that aromatization stability was enhanced. The optimal P loading amount is 0.2 wt%. Introduction of the third element Ga not only promoted n-heptane conversion and aromatization but also restrained hydrogenolysis of middle production and increase liquid yield. The optimal Ga更多还原