The Synthesis And Application Of PtFe Catalysts For Dehydro-aromatization

Benzene, toluene and xylene(BTX) are considered to be the important chemical raw materials, which next to ethylene and propylene. Not only can they be used as chemical raw materials, but also can be used as high-octane gasoline. They have wide applications and the demands are increasing. At present foreign have produced aromatics by catalytic reforming process at large, while in our country the method of pyrolysis gasoline was mainly adopted, which has lower economic benefit. So, the study of produce aromotics by catalytic reforming processing and the preparation of the catalysts have the important application values.At presents, PtSn, PtRe catalysts have been always used in the catalytic reforming precessing on industrial, each has its various advantages and disadvantages. This paper chosed Fe as the second metal components of catalytic reforming catalyst, studied the PtFe/γ-Al2O3 catalysts systematically, investigated the effects of synthesis conditions of catalysts and process conditions on the dehydro-aromatization of methylcyclohexane and n-heptane.Firstly, the role of Fe in PtFe/γ-Al2O3 was studied,through the characterization of the catalysts and the evaluation of the reactions to compare the different performance of Pt/γ-Al2O3 and PtFe/γ-Al2O3. It was showed that the addition of Fe promoted the typical reaction of generate aromatics in catalytic reforming processing. Fe improved the dehydro-aromatization activity of the catalysts, effectively inhibited the side reactions,increased the stability of the catalysts.Secondly, using isometric impregnation method prepared the supported PtFe/γ-Al2O3 catalysts, discussed the influence of different synthesis conditions on the dehydro-aromatization of methylcyclohexane and n-heptane,including loading of Pt, Pt/Fe atomic ratio, impregnation sequence, calcination temperature, calcination time. The results showed that while the Pt loading was 0.4%, Pt/Fe atomic ratio was 1/4, impregnation Fe after dipping Pt and at 500℃ calcination 4h, the catalysts exhibited the best performance.In the end, the dehydrogenation aromatization reaction process conditions were discussed, we studied the effects of reaction temperature and reaction pressure on the dehydro-aromatization of methylcyclohexane and n-heptane. The results showed that the optimum reaction process conditions for methylcyclohexane and n-heptane generate to toluene by dehydro-aromatization were 420℃、0.5MPa and 460℃、1.0MPa.