Application of resin and NH4NO3 as an ion exchange agent for microspherical preparation of nanostructured kaolin-SAPO-34 catalyst for methanol to light olefins reaction in a fluidized bed reactor

Abstract

The aim of this research is to investigate the influence of various ion exchange methods in the assembly of nanostructured kaolin-SAPO-34 catalyst using silica sol as binder by spray drying for conversion of methanol to light olefins in a fluidized bed reactor. Physiochemical properties of the catalysts were identified by XRD, FESEM, EDX, BET, NH3-TPD and FTIR techniques. The results of XRD analysis exhibit typical SAPO-34 and kaolinite phase for all the three spray dried samples. It represents the successful spray drying that the crystallite structure of the shaped samples assumes by the spray dryer that is composed of both kaolinite and SAPO-34 phase. With the comparison of FESEM results of the samples, it can be implied that use of resin as an ion-exchange agent resulted in smoother and larger particles. According to NH3-TPD results at high calcination temperatures, the reaction of silica from the binder with the extra-framework alumina of kaolin or SAPO-34 results in new acid sites. The catalysts mechanical strength was evaluated by the fluidized bed attrition test. MTO Performance tests were carried out to study the activity of the catalysts in a fixed bed reactor. The optimized catalyst was also tested in a fluidized bed reactor. The optimal shaped sample showed excellent activity of near 22 h during MTO reaction in a fluidized bed reactor.