Research For SAPO-34Zeolite Catalyst For Conversion Of Methanol To Olefins

SAPO-34zeolites were synthesized by the hydrothermal methodseparately using MOR, DEA, TEA as template. XRD characterization results show that in our experimental conditions, in addition to the synthesis of SAPO-34molecular sieve used TEAOH as templatealone outside, using other single template can all synthesize purephase SAPO-34molecular sieve successfully. The performance of the catalysts prepared here was experimentally investigated on conversion of methanol to olefins （MTO）. The results showed that the MOR template is relatively optimal.ZnAPSO-34, NiAPSO-34, MgAPSO-34, CaAPSO-34, SrAPSO-34and BaAPSO-34zeolites were synthesized by adding Zn（NO₃）₂,Ni（NO₃）₂, Mg（NO₃）₂, Ca（NO₃）₂, Sr（NO₃）₂and Ba（NO₃）₂into the mixed solution used MOR as the template. The results showed that adding zinc is helpful to improve the selectivity of ethylene. It’s notappropriate for adding metal elements into the mixed solution in order to improve the propylene selectivity. It’s appropriate for addingstrontium into the mixed solution in order to lengthen the life of t he catalyst. Adding metal elements into the catalyst has influence on the acid distribution ang pore structure.The physical chemistry characteristics of SAPO-34zeoliteseparately reacted for different time were investigated based on the XRD,XPS, NH₃-TPD and TG. The results showed that the MTO reactiondoesn’t destroy the original crystalline structure of the SAPO-34molecular structure. The MTO reaction main react on the weak centreswhich are concentrated in the internal of the pore.SAPO-34zeolites were synthesized by the hydrothermal methodseparately using MOR+DEA, MOR+TEA, MOR+TEAOH, MOR+TEAOH+DEA and MOR+TEAOH+TEA as the composite template. The MTO results showed that the MOR+TEAOH is relatively optimal.SAPO-34zeolites were synthesized by the hydrothermal methodusing the composite template of different ratio of MOR/TEAOH（MOR:TEAOH＝0.2,0.5,1,2,5）. The physical chemistry characteristics of SAPO-34zeolite were investigated based on the XRD, BET and NH₃-TPD. The results showed that in addition to the synthesis of SAPO-34molecular sieve used the composite template （MOR/TEAOH=0.2） as template alone outside, using the composite template （MOR/TEAOH=0.5,1,2,5） can all synthesize pure phase SAPO-34molecular sieve successfully. The composite template （MOR/T EAOH=1） is relatively optimal. The ethylene selectivity and the total selectivity separately reached to41.67%and83.66%and the lifeof the catalyst reached to253min.1MT-0.005ZnAPSO-34zeolites were synthesized by the hydrothermal method using the composite template of ratio of MOR/TEAOH equals to1. The MTO results showed that the1MT-0.005ZnAPSO-34zeolite is the worst among1MT-0.005ZnAPSO-34zeolite, MOR-0.005ZnAPSO-34and1MT-ZnAPSO-34.