Effect of water on stability of |HZSM-5 and product distribution in two-stage gasoline synthesis from syngas

The effects of water on the stability of the catalyst and the product distribution were investigated through controlling the amount of water dehydrated from methanol or using HZSM5 pretreated by hydrothermal method at the analogous atmosphere of gasoline synthesis in two-stage process（360℃， 2MPa）. Physicochemical properties of the zeolite were characterized by XRD, BET, FT-IR, SEM, and NH₃-TPD. The results showed that HZSM-5 pretreated by hydrothermal method had smaller crystal size, more mesoporous, and moderate acid sites, which in all result in the enhancement of gasoline yield and the selectivity to iso-paraffins. The steam generated during methanol dehydration led to the deactivation of strong acid over HZSM-5 zeolite.