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以高温煅烧高岭土微球(CKM)为载体,采用原位合成法制备了负载型SAPO-34催化剂(SCKM)。以质量分数2%～10%的NaOH水溶液对高岭土微球进行了预处理。采用XRD、XPS、SEM、N2吸附-脱附对NaOH处理的高岭土微球及原位合成的SAPO-34进行了表征,并在MTO固定床上对合成催化剂的活性进行了评价。结果表明,NaOH水溶液预处理对高岭土微球表面的化学组成、形貌结构以及原位合成SAPO-34负载型催化剂的性能均有显著影响。质量分数4%的NaOH水溶液处理高岭土微球表面合成的SAPO-34催化剂(4-SCKM)在MTO催化反应中的活性最佳,甲醇转化率达到100%,低碳烯烃选择性89.8%,单程寿命964 min,优于非原位合成的SAPO-34催化剂。
The supported SAPO-34 catalyst (SCKM) was prepared by in-situ synthesis using calcined kaolin microspheres (CKM) as carrier. The kaolin microspheres were pretreated with 2% ~ 10% NaOH aqueous solution. The NaOH-treated kaolin microspheres and in-situ synthesized SAPO-34 were characterized by XRD, XPS, SEM and N2 adsorption-desorption. The activity of synthesized catalyst was evaluated on MTO fixed bed. The results showed that NaOH aqueous solution pretreatment had significant effect on the chemical composition, morphology and structure of the kaolin microspheres and the properties of the SAPO-34 supported catalysts synthesized in situ. SAPO-34 catalyst (4-SCKM) synthesized on the surface of kaolin microspheres with mass fraction of 4% NaOH solution had the best activity in the MTO catalysis. The conversion of methanol reached 100%, the selectivity to light olefins was 89.8%, and the one-way life 964 min, better than the SAPO-34 catalyst synthesized in situ.