多级孔ZSM-5/SAPO-34复合分子筛制备及催化MTO性能研究

doi:10.19964/j.issn.1006-4990.2021-0368

摘要/Abstract

摘要：

为制备性能更加优异的甲醇制烯烃（MTO）催化剂及进一步探究多级孔道对MTO催化反应的影响,采用柠檬酸溶液（CA）运用后处理方法对复合分子筛进行刻蚀,成功制备了具有多级孔道结构的ZSM-5/SAPO-34复合分子筛（CA-Z-S）。对复合分子筛的晶相、骨架、孔结构等理化性质进行了表征;将复合分子筛用于催化MTO反应,考察了复合分子筛的催化性能。表征结果表明,使用CA处理对ZSM-5/SAPO-34复合分子筛的形貌、结构会产生影响,使CA-Z-S具有更紧密的复合结构、适量的弱酸中心和多级孔道复合结构。催化测试结果表明,甲醇转化率达到100%时,CA-Z-S的寿命为1 200 min,较SAPO-34提高79%,较ZSM-5/SAPO-34提高30%;CA-Z-S对轻烯烃的选择性达到90.5%,较SAPO-34提高约3.7%。研究结果表明,利用CA对复合分子筛进行后处理,有利于复合分子筛催化MTO反应性能的提升。

关键词: SAPO-34, ZSM-5, 复合分子筛, MTO反应

Abstract:

In order to prepare MTO catalysts with better performance and further investigate the effect of multi-level pores on the catalytic reaction of MTO,ZSM-5/SAPO-34 composite molecular sieve（CA-Z-S） with multi-level pore structure was successfully prepared by etching the composite molecular sieve with citric acid solution（CA） using post-treatment method. The physicochemical properties of the composite molecular sieve,such as crystalline phase,skeleton and pore structure,were also characterized.The composite molecular sieve was used for catalytic methanol-to-olefin（MTO） reaction and its catalytic performance was investigated.The characterization results showed that the treatment with CA would have effect on the morpho-logical structure of the ZSM-5/SAPO-34 composite molecular sieve,resulting in a more compact composite structure,a mod-erate amount of weak acid centers and a multi-level pore composite structure of CA-Z-S.The catalytic test results showed that the lifetime of CA-Z-S was 1 200 min at 100% methanol conversion,which was 79% higher than that of SAPO-34 and 30% higher than that of ZSM-5/SAPO-34.The selectivity of CA-Z-S for light olefins reached 90.5%,which was about 3.7% higher than that of SAPO-34.The results indicated that the post-treatment of the composite molecular sieve with CA was beneficial to the performance of the composite molecular sieve catalyzed MTO reaction.

Key words: SAPO-34, ZSM-5, composite molecular sieve, MTO reaction

中图分类号:

TQ426.6

王银忠,秦冬玲,杨刚. 多级孔ZSM-5/SAPO-34复合分子筛制备及催化MTO性能研究[J]. 无机盐工业, 2022, 54(3): 119-124.

WANG Yinzhong,QIN Dongling,YANG Gang. Study on preparation of hierarchical ZSM-5/SAPO-34 composite molecular sieve and its MTO performance[J]. Inorganic Chemicals Industry, 2022, 54(3): 119-124.

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参考文献 21

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样品	BET比表面积/（m²·g^-1）			孔容/（m³·g^-1）
样品	S_BET	S_micro	S_ext	V_total	V_micro	V_meso
SAPO-34	551.54	545.89	5.65	0.27	0.26	0.01
Z-S	367.70	180.85	186.85	0.26	0.24	0.02
CA-Z-S	487.23	456.64	30.59	0.21	0.09	0.12
ZSM-5	276.13	229.75	46.37	0.16	0.12	0.04

样品	w（Al）/%	w（Si）/%	w（P）/%
ZSM-5	0.63	76.65	—
Z-S	31.75	34.82	33.54
CA-Z-S	24.58	35.11	32.73
SAPO-34	45.61	13.70	46.75

样品	反应时间/min	产品选择性*/%				甲醇转化率/%
样品	反应时间/min	C₂⁼	C₃⁼	C₄⁺	C₂⁼+C₃⁼	甲醇转化率/%
ZSM-5	1 500	39.2	43.7	17.1	82.9	89
Z-S	840	45.6	44.2	11.2	89.8	100
CA-Z-S	1 200	46.1	44.4	9.5	90.5	100
SAPO-34	250	47.2	39.6	13.2	86.8	100

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