【作者】 刘建亮；

【导师】 王金渠；

【作者基本信息】 大连理工大学 ， 化学工艺， 2005， 硕士

【摘要】 Silicalite-1沸石属于MFI型沸石中的一种,其骨架结构不含Al,具有比ZSM-5沸石膜更高的热稳定性、疏水和亲油特性,不仅用于气体分离,更可用于苛刻条件下的反应体系。研究高质量的Silicalice-1沸石膜的合成及应用于乙苯脱氢制苯乙烯反应,仍是一项艰巨的任务,有许多工作要做。本论文主要进行以下研究工作:系统研究了Silicalite-1沸石膜合成过程中一些重要因素的影响,通过优化条件直接在孔径3-5μm的陶瓷载体上合成高渗透率Silcialite-1沸石膜;探讨了在不同载体表面进行Silicalite-1沸石膜的合成;将合成的膜组装成膜反应器应用于乙苯脱氢反应中,并取得了较好的分离效果。一研究了晶化方式、合成次数、不同晶种引入方式、晶化温度和载体预处理方式等因素对成膜及膜性能的影响。结果显示用自制Silcialilte-1沸石分子筛为晶种,用提拉的方式引入到载体上,并在旋转的方式下,重复合成3次,可以得到完整连续的Silicalite-1沸石膜,室温下,H2的渗透率达到12. 26×10-7mol/(m2·s·Pa),H2/C3H8的分离因数达到13. 55。优化条件后直接在α-Al2O3陶瓷管上合成了高渗透率、高选择性的Silicalite-1沸石膜,H2的渗透率高达2. 73×10-6mol/(m2·s·Pa),比文献报道高出近一个数量级,H2/N2、 H2/C3H8的理想选择因数分别为3. 72和24. 59。二研究了变温晶化对合成Siliealite-1沸石膜的影响,并首次在大面积不锈钢管上合成高质量的Silicalite-1沸石膜,H2的渗透率为4. 77×10-7mol/(m2·s·Pa),H2/C3H8的理想选择因数为14. 77。三将合成的沸石膜组装成膜反应器应用于乙苯脱氢反应体系,并考察了抽真空、液体空速、反应温度和吹扫气速对反应体系的影响。随着膜管两侧压差的增加,副产物苯几乎不变,甲苯略有上升,二段乙苯的转化率有明显提高,苯乙烯选择性略有下降。发现液体空速大时,副产物苯和甲苯略有降低,苯乙烯选择性提高,但乙苯的转化率有所下降。通过使用N2气吹扫时,二段反应器乙苯的转化率和苯乙烯的选择性提高更明显,二段反应器乙苯的转化率比常压下提高了7. 52%。更多还原

【Abstract】 Silicalite-1 zeolite is one of the MFI zeolites, has made it be of withstanding higher temperature, higher hydrophobicity compared to ZSM-5 zeolite membrane, because of no Al in its structure, which has been applied not only in gas separation, but also in the reaction system of harsh condition. So, there is still much work to do in studying the preparation of Silicalite-1 zeolite membrane with high quality and its application in dehydrogenation of ethylbenzene to styrene.The main work of this paper is: (1) Effects of some important factors on the preparation of Silicalite-1 zeolite membranes are thoroughly studied. High-penetration Silicalite-1 zeolite membrane were synthesized on the a-Al2O3 support with pores of 3-5μm; (2) High quality Silicalite-1 zeolite membranes was prepared by in situ hydrothermal synthesis on different substrates; (3) membrane reactor was used in dehydrogenation of ethylbenzene to styrene under the circumstances of industry production and got a good result.The influence of crystallization methods and synthesis times and the methods of introducing seeds and the pretreatment methods of substrate were studied thoroughly. The results showed that using self-product Silicalite-1 zeolite as seeds and introducing them to the support and crystallizing three times using the rotary methods, integrated and continuous membranes were gained. The penetration of H2 is 12.26×10-7 mol/(m2 s Pa) and the ideal selectivity of H2/C3H8 is 13.55. It was reported that high quality Silicalite-1 membrane was directly prepared on the porous support in optional conditions. The permeation of H2 is up to 2.73 × 10-6 mol/(m2 s Pa) and it is almost one order of magnitude higher than that of the literature. The ideal selectivity of H2/N2 and H2/C3H8 is 3.72 and 24.59 respectively.Two-stage varying-temperature synthesis was introduced to the synthesis of zeolite membranes. The influence of varying-temperature on zeolite membranes was studied. High quality Silicalite-1 zeolite membranes were synthesized on the porous stainless steel support with pores of 3-5 μm, the large membranes were successfully prepared on tubular supports. The permeation of H2 is 4.77×10-7 mol/(m2 s Pa), The ideal selectivity H2/C3Hg is 14.77.The membrane reactor was used in dehydrogenation of ethylbenzene to styrene under the circumstances of industry production. The experimental results indicated that the conversion of ethylbenzene in the membrane reactor increased with the pressure and temperature and thesweep gas speed increasing. Using sweep gas instead of the vacuumizing, the result under the same conditions showed that the selectivity of styrene increased and the conversion of ethylbenzene in the membrane reactor increased by 7.52% in comparison with the fixed-bed reactor, which had been tested by a long time.更多还原