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

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

模拟两段法合成汽油工艺的反应条件(360℃、2 MPa),通过控制甲醇的脱水量或在该气氛下对HZSM-5进行水热预处理,考察了水对催化剂稳定性及油相产物的影响。XRD、BET、FT-IR、SEM和NH3-TPD等表征手段表明水热预处理后的分子筛具有晶粒小、中孔多和酸强度低等特点,能显著提高汽油收率和异构烷烃选择性。甲醇在HZSM-5分子筛上发生脱水反应,产生的水热气氛造成强酸中心失活。

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.