SAPO-34晶粒形貌对甲醇转化制低碳烯烃反应的影响  

Effect of SAPO-34 molecular sieve morphology on methanol to olefins performance

作　　者：吴磊[1,2] 刘子玉[1] 夏林[1] 丘明煌[1] 刘旭[1] 朱浩佳[1] 孙予罕[1,3] 

机构地区：[1]中国科学院上海高等研究院低碳转化科学与工程中科院重点实验室,上海201203 [2]中国科学院大学,北京100049 [3]中国科学院山西煤炭化学研究所煤炭转化国家重点实验室,山西太原030001

出　　处：《催化学报》2013年第7期1348-1356,共9页

摘　　要：分别采用微波和水热法合成了具有片状及立方结构的SAPO-34分子筛.结果发现,片状SAPO-34分子筛晶粒厚度为130nm,比表面积为593m2/g;立方结构SAPO-34分子筛粒径为1.5–2.5μm,比表面积为708m2/g.二者具有数量相近的强酸中心,后者的弱酸位数量略少.甲醇制烯烃反应结果表明,在450oC和1.0h1的反应条件下,片状SAPO-34分子筛的催化寿命可达380min,乙烯选择性最高为51.77%,乙烯、丙烯及丁烯的总选择性最高为90.20%;而立方结构SAPO-34的催化寿命仅为212min,乙烯选择性最高为49.84%,乙烯、丙烯及丁烯的总选择性最高只有86.81%.这可能源于片状晶粒的扩散路径较短,抑制了低碳烯烃的进一步转化及积碳的生成,因此具有较高的低碳烯烃选择性及较长的寿命.SAPO‐34 molecular sieve samples with sheet‐like and cubic morphology were synthesized under microwave and hydrothermal conditions, respectively. The sheet‐like SAPO‐34 was 130 nm thick with a Brunauer‐Emmett‐Teller （BET） surface area of 593 m2/g, while the cubic sample was 1.5–2.5 μm in size with a BET surface area of 708 m2/g. Both samples exhibited a similar density for strong acid sites, while the cubic SAPO‐34 possessed less weak acid sites. A methanol to olefins catalytic test carried out at 450 ℃ and 1.0 h-1 showed that the sheet‐like SAPO‐34 exhibited a long stability life of 380 min and gave a high ethylene selectivity of 51.77% and a high total selectivity for ethylene, propylene, and butylene of 90.20%. However, the stability life for the cubic SAPO‐34 was only 212 min, and the ethylene selectivity and total selectivity for ethylene, propylene, and butylene decreased to 49.84% and 86.81%, respectively. It is thought that the longer stability life and higher olefin selectivity for sheet‐like SAPO‐34 occur because of the shorter diffusion path that hinders the further conversion of produced olefins and coke formation.

关 键 词：SAPO-34分子筛 形貌 甲醇制烯烃 反应温度 空速 

分 类 号：O643.32[理学—物理化学]