Synthesis of light olefins from methanol on co/zsm-5 catalyst

Abstract

This research focused on investigation on characteristic and catalytic properties of H/ZSM-5 and Co/ZSM-5 zeolite catalyst used for methanol conversion. In fact, four of H/ZSM-5 zeolite catalysts having different Si/Al ratios (20, 50, 80 and 150), were synthesized by hydrothermal method. Those catalysts were tested in various reaction temperatures ranged between 200-500 0C in order to select the suitable Si/Al ratio and reaction temperature. Base on light olefin yield, it was found that the H/ZSM-5 zeolite catalyst at Si/Al of 80 was the suitable catalyst at 300 0C reaction temperature for methanol conversion into light olefins. In addition, three of H/ZSM-5 zeolite catalysts, having different particle sizes (1.8, 3.4 and 4.7 μm) were synthesized to determine the effect of cobalt loading (1%, 5% and 10% wt) in the H/ZSM-5 zeolite catalyst. The H/ZSM-5 zeolite catalyst and Co/ZSM-5 zeolite catalysts with 1 wt%, and 5 wt% of Co loading did not exhibit significant change in olefin selectivity. On the other hand, the various particle sizes of 10% wt Co/ZSM-5 zeolite catalyst affected the light olefin selectivity. The small particle size (1.8 μm) showed the greater light olefin selectivity than the larger Co/ZSM-5 particle sizes (3.4, 4.7 μm) because cobalt species dispersed in the channel of small particle size than large particle size. The cobalt species dispersed in the channel also affected the changes in the resident time and product selectivity.