Study On The Nano-sized ZSM-5 Catalyst Of Mixed C₄ Aromatization At The Low Temperature And Hydrogen Processing

The technical of mixed C4 aromatization at the low temperature and existence of hydrogen to produce high octane number gasoline is a new comprehensive utilization of C4 resource process. The catalysts of the process are nano-sized ZSM-5 catalysts which comes from Dalian University of Technology, and the reaction produces the gasoline of aromatization which the RON octane number is as high as 102 in the presence of catalyst by the reaction conditions of 360℃～420℃,2.0MPa, WHSV=1.0h-1, H2/oil volume ratio 50:1, and also produces the LPG(which consists of C3> C4 alkanes and olefins) which contains very rarely olefin hydrocarbon and dry gas as byproducts. The conversion of the olefin with four carbon atoms in the feedstock exceeds 98%.The reaction of mixed C4 aromatization is very complicated, which the feedstock contains mainly C3、C4 alkanes and olefins; however the reaction products are consist of C1～C11 hydrocarbons; the major reactions are polymerization、cyclization、β-site C-C bond cracking、 alkylation、aromatization、dehydrogenation、hydrogen transfer and dealkylation by the hydrogenolysis of cyclic hydrocarbons. The key factor for this reaction is the larger number of B-acid and L-acid activity centers, which were provided by the special surface structure and properties of the nano-sized ZSM-5 catalyst.On the basis of experiments, this paper have examined and analyzed the performance of nano-sized ZSM-5 catalyst, researched the mutual transformation relationship between aromatization products and mixed C4, confirmed that H2、C4 olefins and isobutene are the key components in feeds, explored the reaction mechanism of mixed C4 aromatization at low temperature and existence of hydrogen, raised the reaction process with the intermediate of carbonium, which provides a basis for developing more excellent performance catalyst and for improving technology in the future.