Abstract:
The two consecutive layers of a microporous catalyst and a mesoporous material with the same seed type of microporous catalyst were employed in order to transform bio-ethanol into hydrocarbons. The first layer was filled with either microporous HZSM-5 or HBeta zeolites whereas the second layer was filled with a hierarchical mesoporous MSU-S with corresponding either ZSM-5 or Beta seeds were studied in the first scope. Moreover, in the second scope, the catalytic activity and product distribution using HZSM-5, HBeta, MSU-Szsm-5, and MSU-SBEA were studied by varying time-on-stream. The results showed that the presence of MSU- Szsm-5 and MSU-SBEA in the second layer cannot produce heavier hydrocarbons than a single bed of microporous HBeta and HZSM-5 zeolite. Nevertheless, they promoted the trans alkylation and dealkylation of C9+ aromatics, produced from the first layer, into toluene and mixed xylenes, Furthermore, in the second scope, HZSM-5 gave a higher selectivity of heavy fractions such as ethylbenzene, C9, and C10+ aromatics in contrast to the results from MSU-Szsm-5 that C10+ aromatics selectivity decreased with increasing TOS due to coking. On the other hand, HBeta showed a fast deactivation via coking on the acid sites and pore blocking, but MSU- SBEA provided a slower deactivation than HBeta, and gave a high selectivity of nonaromatic fraction, which was mostly composed of olefins. In addition, the structure of all catalysts were not destroyed during bio-ethanol.
