FCC废催化剂镁改性催化裂化性能再生研究

提出并证实了高的强酸性位可接近性导致FCC废催化剂失活的机制。基于所提出的失活机制，采用浸渍法对FCC废催化剂进行镁改性再生。对所制备的再生FCC废催化剂进行了表征并考察了其重油催化裂化性能。表征结果表明，与未改性的FCC废催化剂相比，再生FCC废催化剂表面酸强度被一定程度地削弱，而表面总酸量和结构性质参数未出现显著改变。重油催化裂化结果表明，得益于适宜的表面酸性，再生FCC废催化剂的催化裂化反应性能得到极大改善。与未改性的FCC废催化剂相比，再生FCC废催化剂的汽油产率显著增加了3.04个百分点，同时干气、液化气、焦炭和重油产率则分别下降了0.36、0.81、1.28和0.87个百分点，这使得所制备的再生FCC废催化剂可以代替部分新鲜FCC催化剂使用。最后，探讨了再生FCC废催化剂表面酸性改变机理。

Research on catalytic cracking performance regeneration of spent FCC catalyst by magnesium modification

In this study, the deactivation mechanism caused by high accessibility of strong acid sites for the spent FCC catalyst was proposed and proved for the first time. Base on the proposed deactivation mechanism, magnesium modification by magnesium chloride impregnation was employed for the regeneration of spent FCC catalyst. The regenerated spent FCC catalyst was characterized and tested its heavy oil catalytic cracking performance. The characterization results indicated that, in compared with unmodified spent FCC catalyst, the acid sites strength of the regenerated spent FCC catalyst was weakened, with no prominent alterations for the total acid sites quantity and texture properties. Heavy oil catalytic cracking results suggested that catalytic cracking performance of the regenerated spent FCC catalyst was greatly improved due to the suitable surface acidity of the sample. In contrast with unmodified spent FCC catalyst, the gasoline yield of the regenerated spent FCC catalyst significantly increased by 3.04 percentage points, meanwhile the yields of dry gas, LPG, coke and bottoms obviously decreased by 0.36, 0.81, 1.28 and 0.87 percentage points respectively, which made the regenerated spent FCC catalyst could be as partial substitution for the fresh FCC catalyst. Finally, the acid properties change mechanism was discussed.