摘要
采用水热包覆法制备了Zr O_2/SAPO-34复合催化剂,研究了Zr O_2预处理方式对复合催化剂物化性质和MTO催化性能的影响。采用XRD、FT-IR、SEM、NH_3-TPD和BET等手段对不同复合催化剂的晶相组成、骨架结构、微观形貌、表面酸性质及孔结构进行分析表征。结果表明,Zr O_2预处理方式对复合催化剂物化性质和MTO催化性能影响较大。未焙烧和焙烧经聚电解质改性Zr O_2制得复合催化剂未形成连续复合相,比表面积小,表现出较短的催化寿命,仅为410 min和530 min;450℃焙烧Zr O_2制得复合催化剂形成了均匀连续复合相和层级结构孔特征(微孔比表面积112.91 m^2·g^(-1),介孔比表面积176.02 m^2·g^(-1),总比表面积为288.93 m^2·g^(-1),总孔容0.19 cm^3·g^(-1)),总酸量较大(0.344 mmol/g);在常压、反应温度380℃、N_2流速20 m L·min^(-1)、进料空速2 h^(-1)MTO反应条件下,复合催化剂表现出优越催化性能、稳定性及反应寿命,甲醇转化率和低碳烯烃选择性分别达100%和90.54%,催化寿命达1130 min,与单一SAPO-34分子筛相比,催化寿命延长了768 min。
The ZrO2/SAPO-34 composite catalysts were prepared via hydrothermal coating method, and effect of various ZrO2 pretreatment methods on the physicochemical properties and MTO catalytic performance of the composite catalyst was investigated in this paper. These obtained products were extensively characterized by XRD, FT-IR, SEM, crystalline phase, skeletal structure, morphology, NH3-TPD and BET techniques to investigate their surface acidity and pore structure. The results indicated that various ZrO2 pretreatment methods posed significant impact on the physicochemical properties and MTO catalytic performance of ZrO2/SAPO-34 composite catalyst. The composite catalyst prepared from zirconium precursor and ZrO2 impregnated with little continuous composite phase and low specific surface area exhibited inferior catalytic performances with short catalytic life of respectively 410 min and 530 min. The homogeneous continuous composite phase and hierarchical structure with total amount of acid of 0. 344 mmolfg were obtained from ZrOz calcined at 450 ℃（microporous specific surface area of 112.91 mE ·g-1, mesoporous specific surface area of 176.02 mE ·g-1 , total specific surface area of 288.93 m2 ·g-1, the total pore volume of 0.19 cm3·g-1） , and the composite catalyst exhibited excellent catalytic performances, stability and reaction life with methanol conversion of 100% , light olefins selectivity of 90.54%, and catalytic lifetime of 1130 min under the conditions of atmospheric pressure, reaction temperature of 380 ℃, nitrogen flow rate of 20 mL · min^-1 and feed speed of 2 h^-1. Compared with the single SAPO-34 molecular sieve, the catalytic lifetime of the ZrO2/SAPO-34 composite catalyst was extended by 768 min.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2018年第1期43-50,共8页
Journal of Synthetic Crystals
基金
国家自然科学基金(21666007)
贵州省百层次创新型人才专项(黔科合平台人才[2016]5655)
贵州省重点科学技术基金(黔科合JZ字2014-2007)
贵州省联合基金项目(黔科合LH字[2017]7260号)
