不同结构的分子筛在1-丁烯中催化裂解性能的研究

我们合成了不同Si含量的SAPO-18,并且利用了XRD、SEM、NH3-TPD进行了表征分析.利用微反固定床反应器评价了代表不同结构的H-ZSM-5(MFI)、H-Beta(* BEA)、SAPO-18 (AEI)系列分子筛的丁烯催化裂解性能.实验结果表明分子筛的结构和酸性对反应结果都有明显影响,分子筛酸量的增加提高了1-丁烯的转化率,但酸量过高会引发氢转移、芳构化副反应,从而降低丙烯的选择性;分子筛孔口大小、孔道结构决定了可以获得的最高丙烯选择性.具有八元环孔口、笼形结构特点的SAPO-18-0.8在线时间20 min时1-丁烯裂解中转化率为60.7％,获得的丙烯选择性达到59.1％.

Catalytic Performance of Molecular Sieves with Different Structures in 1-Butene Cracking

SAPO-18 with different contents of Si were synthesized and characterized by XRD, SEM and NH₃-TPD. Catalytic performance of H-ZSM-5(MFI), H-Beta(*BEA) and SAPO-18(AEI) as different types of molecular sieves have been investigated for of 1-butene cracking reaction in a fixed-bed microreactor. It was found that the acidity and structure of molecular sieves play key roles in the catalytic results of 1-butene catalytic cracking process. These results showed that the high acidity of catalysts improved the 1-butene conversion but led to the decrease of the selectivities of propylene owing to the side reactions (such as hydrogen transfer, aromatization) derived from additional acid sites. What is more, the pore dimension and channel structure determined the available selectivity of propene. SAPO-18-0.8 with eight-ring pore and pear-shaped cage was achieved satisfactory propylene selectivity approach 59.1% with 1-butene conversion was 60.7% under the TOS of 20 min condition.