刻蚀构筑HZSM-5催化剂调控MTO反应产物分布的研究

Regulation of product distribution for MTO reaction over HZSM-5 catalyst etched

采用3-氨丙基三乙氧基硅烷(KH-550)为刻蚀剂制备了KH-550-HZSM-5系列催化剂,利用XRD、SEM、NH3-TPD、FT-IR表征手段对催化剂的结构、形貌及酸性变化进行测试,并在固定床中进行催化MTO反应的性能评价。结果表明,从催化剂性能及经济性评估,KH-5500.3-HZSM-5催化剂在温度为490℃、常压、氮气流量为20 mL/min、WHSV=1.08 h^(-1)、催化剂质量为0.5 g、石英砂质量为5 g条件下,甲醇的转化率为100%,乙烯和丙烯的总选择性约为64.95%,烯烃总选择性为85.90%;然而,与HZSM-5相比,C+9的总选择性从22.03%降到7.12%。

KH-550-HZSM-5 series catalysts are prepared by using 3-aminopropyl triethoxysilane(KH-550)as etching agent.The structure,morphology and acidity of the catalysts are measured by means of XRD,SEM,NH3-TPD and FT-IR characterizations,and the performance in catalytic MTO reaction is evaluated in a fixed bed.It is shown from the comprehensive evaluation of performance and economy of the catalysts that the conversion rate of methanol can reach 100%,total selectivity of ethylene and propylene can reach around 64.95%,and total selectivity of olefins can reach 85.90%when the temperature remains at 490℃,the pressure is atmospheric,nitrogen flow is 20 mL·min^(-1),WHSV=1.08 h^(-1),5 g of quartz sand is used and 0.5 g of the catalyst that is prepared by using 0.3 g of KH-550 is added.Compared with that over HZSM-5,total selectivity of C_(9)+over KH-550-HZSM-5 drops from 22.03%to 7.12%.