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Toluene Disproportionation And C9 Transalkylation Reaction Catalyzed By Modified Nanosized HZSM-5

Posted on:2007-12-14Degree:MasterType:Thesis
Country:ChinaCandidate:G J QiFull Text:PDF
GTID:2121360182983914Subject:Industrial Catalysis
Abstract/Summary:PDF Full Text Request
Increasing the yield of benzene and xylene in the toluene disproportionation and the transalkylation of C9 arenes is an effective method to adjust the productive and required balance of each component in arenes and to meet the need of petrochemical industry for benzene and xylene. It is significant to develop the high performance of catalysts in the toluene diproportionation and the transalkylation of C9 arenes reactions. Recently, the large pore zeolites such as mordenite, 3 -zeolite, were applied to the reaction of the toluene disproportionation and the transalkylation of C9 arenes for increasing the amount of benzene and xylene in industrial scale. In this paper, the novel catalyst using nanosized ZSM-5 as parent for the transalkylation reaction was studied and made full use of the special properties of the nanosized HZSM-5.Nano-particle is one novel material with special physico-chemical properties and has become one of the hot focuses in the catalytic field because of its significant volume effect, surface effect and quantum size effect. As one kind of catalysts, the nanosized HZSM-5 shows better performance for the reactions: high activity;the perfect repeated usage and long life. Therefore, the catalysts which show the better catalytic performance in toluene disproportionation and the transalkylation of C9 arenes to benzene and xylene that are great needed in market are desired to be used.In this paper, the single modified catalysts were prepared with the metal oxides as well as acid based on nanosized HZSM-5 extrude with alumina. The compound modified catalyst prepared by metal oxide and acid with cycle of impregnant and calcination. The catalytic performance of toluene disproportionation and C9 arenes on modified catalyst were investigated and indicated that the catalytic performance of anahz-i is excellent. The conversion is 48% and 46% after 20 and 70hour, respectively, and the selectivity of toluene and xylene in the liquid product retained 96%. When fed contained 7% C10 arenes, the total conversion exceed 82 %. Compared to industrial catalysts of toluene disproportionation and C9 arenes transalkylation, the following conclusions were concluded:1.Combined modified catalyst ( ANAHZ-1 ) dramatically catalyzed toluene disproportionation and C9 transalkylation reaction. Compared to micro-catalysts, the above catalysts can achieve the same conversion and selectivity to toluene and xylene or even better.2. Combined modified catalyst (ANAHZ — 1 ) has high conversion of C9 arenes transalkylation.3. Combined modified catalyst (ANAHZ—1) also has high conversion of C10arenes transalkylation to increase C9 arenes and make full use of the cheap heavy crude arenas containing C10 arenes in the feed.
Keywords/Search Tags:Nanosized HZSM-5 zeolite, Disproportionation and Transalkylation, Heavy Crude Aromatics, Single Modification, Combined Modification
PDF Full Text Request
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