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چکیده
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In this study, we have investigated the effect of water co-feeds on products distribution and coking behavior of a new composite catalyst in the MTG process. A novel ZSM-5/Beta bi-phase composite catalysts were synthesized via a hydrothermal crystallization method. Catalysts were all characterized by considering their crystallinity (XRD analysis), morphology (FE-SEM analysis), surface area, pore volume (N2 adsorption/desorption technique), and acidity (NH3-TPD analysis). The catalytic performance of the synthesized catalysts was tested by the MTG reaction in WHSV of 20 h 1, the temperature of 400 ◦C, atmospheric pressure, and water content of 0, 10, and 20%. Over the ZSM-5/Beta composite catalyst, the methanol diluted with 10% water resulted in a 29% yield of gasoline compared with 21% over ZSM-5 and 66% selectivity to alkylated aromatics compared with 45% over ZSM-5. Adding water to the methanol had a key role in improving catalysts lifetime so that by using the feed with 10 wt% water, a lifetime about two times longer than pure methanol was observed. The higher activity over the ZSM-5/Beta sample co-feed with 10% water, was ascribed to overcoming the diffusion limitations and retarding catalyst deactivation in the presence of water.
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