Comparison of Catalytic Properties and Cracking Activities of FCC Catalysts bound with Different colloidal Binders: Silica, Alumina and Silica-Alumina sol

In this paper, catalytic properties and cracking activity of FCC catalysts synthesized with different colloidal binders including silica sol, alumina sol and silica-alumina sol, were evaluated and compared with each other. The catalysts were prepared by incorporation of silica-alumina matrix, kaolin, colloidal binder and Y-zeolite under the same conditions, ion-exchanged with ammonium solution and calcined at 600 °C. Temperature programmed desorption of ammonia (NH3-TPD) and BET surface area measurements were used to characterize the catalysts. It was found that the FCC catalyst made with silica binder (FCC-S) had higher acidity than the other ones, due to Si insertion from silica binder to the zeolite framework at calcination step. The FCC catalyst bound with silica-alumina binder (FCC-S.A) provided the highest surface area. We used triisopropylbenzene (TiPB) as an FCC feed model compound in our experiments, in order to understand the cracking activities of the catalysts. During the whole times on cracking, the TiPB conversion followed this order: FCC-S.A>FCC-A>FCC-S. As a result of greater accessibility of acid sites, FCC-S.A offered more conversion than the others. The alumina-bound catalyst (FCC-A) yielded more valuable products (diisopropylbenzene and cumene) compared to the others

کلیدواژه ها:

Colloidal Binder ، Cracking Activity ، Acidity ، Surface Area