Development of Catalytic Zeolite Membrane and Its Application to Simultaneous Resction and Separation

沸石是晶体铝硅酸盐，广泛用作催化剂和吸附剂。mfi型沸石晶体内部有细小的孔洞，孔洞的直径与苯的分子大小几乎相同。因此，分子筛具有较高的分子筛分效果。当沸石成功制备成膜状时，膜可以实现新的分离和高性能的同时反应分离。本项目主要目的是开发mfi型沸石催化膜，并将其应用于高分离和同时反应分离工艺。在1997财政年度，我们进行了以下研究工作：成功地用一种新的方法——充分混合的水热合成法制备了mfi型无针孔催化膜。这种膜被发现显示出对热冲击和机械冲击的高证明，并在773 K以上使用。二甲苯和二乙基苯对邻异构体的分离系数分别为3和7。在1998财年，将该膜应用于高分离和同时反应分离过程中，得到了以下结果：1)浓乙酸对水的选择性渗透：在温度为343 K ~ 363 K，乙酸浓度为20% ~ 98%的条件下，只有水可以通过膜。2)从氢气与氮气、氧气和二氧化碳的混合物中选择性分离氢气：在483 k的流动系统中，氢气与其他气体的分离系数约为100。3)同时反应和再生：甲醇的反应是连续反应，如甲醇（]SY）。tri-substituted离开了。[) ether ()；tri-substituted离开了。[]烯烃；tri-substituted离开了。()石蜡+芳烃。甲醇扩散通过催化沸石膜进行反应。当甲醇转化为烯烃时，它们完全穿过膜，达到烯烃的高选择性。烯烃的选择性提高到85%，而传统固定床反应器的选择性仅为7%。少

Zeolites are crystalline alumino-silicate, and widely used as catalysts and adsorbents. MFI-type zeolite has fine pores within its crystals, the diameter of which is almost the same as the molecular size of benzene. Hence, the zeolite shows high molecular-sieving effect. When the zeolite is succeeded to be prepare in the shape of membrane, the membrane can enable to realize new separation and simultaneous reaction and separation with high performance. The main objective of this project is to development of MFI-type zeolite catalytic membrane, and to apply it to high separation and simultaneous reaction and separation processes.In fiscal year of 1997, we conducted the following research work :MFI-type catalytic membrane was succeeded to prepared without any pin-holes by a new method, well-mixed hydrothermal synthesis. This membrane was found to show high proof against thermal and mechanical shocks and to be used at above 773 K.The separation factor of para- to ortho-isomers of xylene an … More d diethyl-benzene was 3 and 7, respectively.In fiscal year of 1998, the membrane was applied to high separation and simultaneous reaction and separation processes, and the following results were obtained :1) Selective permeation of water from concentrated acetic acid : only water can permeate through the membrane under the conditions of temperature from 343 K to 363 K and the concentration of acetic acid from 20 to 98%.2) Selective separation of hydrogen from mixtures of hydrogen with nitrogen, oxygen and carbon dioxide : the separation factor of hydrogen to the other gas was found to be about 100 in the flow system at 483 K.3) Simultaneous reaction and regeneration : Reaction of methanol is a consecutive reaction, such as methanol (]SY.tri-substituted left.[) ether (]SY.tri-substituted left.[) olefin (]SY.tri-substituted left.[) paraffin+aromatics. Methanol diffuses through the catalytic zeolite membrane undertaking the reaction. When methanol is converted to olefin, they pass completely through the membrane, attaining high selectivity of olefin. The selectivity of olefin was enhanced up to 85% as compared with only 7% for the usage of conventional fixed bed reactors. Less