【作者】 张丽；

【导师】 宁英男；

【作者基本信息】 大庆石油学院 ， 化学工艺， 2009， 硕士

【摘要】 本研究从分析气相聚乙烯催化剂的合成反应机理入手,开发了一种适用于乙烯聚合或共聚合的新型高活性干粉催化剂。该催化剂体系是在目前国内普遍使用的M催化剂体系的基础上进行改进,由SiO₂、THF、MgCl₂、TiCl₃和给电子体等组成。在催化剂制备过程中,应用的给电子体化合物可与载体SiO₂发生弱的化学作用,绑定活性组分。因此通过给电子体的作用,一方面可以提高活性组分的负载量,使催化剂具有更高、更稳的活性;另一方面还可以使活性组分进入二氧化硅载体的微孔中,提高聚合产物堆密度,改善共聚性能和氢调敏感性能,从而有效提高聚合物的质量。在催化剂的制备过程中,考察了载体种类、催化剂制备条件及给电子体种类改变对催化剂性能等的影响,并考察了该催化剂的共聚性能和氢调敏感性能。根据试验结果可知:Mg/Ti摩尔比为2.5、每克硅胶负载含0.15g MgCl₂的母液、THF/Ti摩尔比为2.0、AlEt₂Cl占总铝比例的47%、Al（总铝含量）/Ti摩尔比为4.5和给电子体A是催化剂制备的最优制备条件;催化剂在活性、氢调敏感性及共聚性能方面均优于M催化剂,且聚合产物的粒度大、分布集中、细粉含量少。且该催化剂呈类球型,具有较好的形态,在聚合过程中放热均匀、活性稳定、生产运行平稳,适于Unipol工艺气相装置目前普遍采用的冷凝态操作技术。更多还原

【Abstract】 With the development of the ethylene gas phase polymerization technology,the M catalyst does not suit the condensed and super-condensed technology to produce polyethylene in the polymerization.So a new type catalyst based on catalyst synthesis reaction mechanism is introduced in this paper,and it is used for ethylene polymerization and copolymerization.The catalyst modified on the basis of M catalyst is also made from SiO₂,MgCl₂,TiCl₃ and THF, but some compound as electron donor compound is added in the preparation of the catalyst. Due to adding the compound,there is a weak chemical reaction of the electron donor with the silica supports,which could bind some active constituent.Because of the electron donor,on the one hand,the load of active constituent enhanced,which increased the activity of the catalyst;on the other hand,electron donor made the active constituent enter the tiny hole of the Silica carrier to enhance the bulk density of the polymers,and boost the quality of the polymer.On the preparation of the catalyst,the effects on different kinds of carrier,catalyst preparation conditions and electron donors on catalytic systems are studied.Hydrogen response and copolymerization performanceare also studied in the polymerization process.From the experiment results we know that the optimal catalyst preparation conditions are when the Mg/Ti moler ratio is 2.5,MgCl₂/SiO₂ mass ratio is 0.15,THF/Ti moler ratio is 2.0, the percentage of AlEt₂Cl is 47%,Al/Ti is 4.5 and electron donor A is used.The new type catalytic system for ethylene polymerization is much better than M catalytic system,which has not only improved the activity of the catalyst and good particle morphology of products, reduced fine power content of polymer product,but also has good hydrogen response and copolymerization performance.The catalyst is quasi-spherical,has good morphology,sents out heat uniformly and operates steadily.The new novel catalyst is very suitable for the condensation operation in Unipol gas phase fluidized bed polyethylene technology.更多还原