Effect of water on stability of HZSM-5 and product distribution in two-stage gasoline synthesis from syngas
水对两段法合成汽油中HZSM-5分子筛稳定性及油相产物的影响

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 ℃, 2 Mpa). Physicochemical properties of the zeolite were characterized by XRD, BET, FT-IR, SEM, and NH_3-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.