小孔沸石分子筛膜及其钯复合膜的制备与应用

发布时间：2018-03-21 16:01

本文选题：小孔沸石分子筛膜　切入点：钯复合膜　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：在环境问题日益严重的今天,氢气作为一种绿色的能源得到了普遍的青睐,然而氢气是一种二次能源,需要通过水煤气法、石油热裂解等方法制备得到,但这些方法同时还会产生CO2、N2及一些含碳化合物等副产物,因此对于氢气提纯的研究显得至关重要。沸石分子筛膜作为一种新型的无机膜材料在气体分离领域己成为研究热点。按照孔道结构和孔径的大小,沸石通常可以分为小孔、中孔、大孔材料等,其中一些小孔沸石分子筛如SAPO-34 (0.38x0.38 nm)、DDR (0.36x0.44 nm)等具有与某些小分子气体直径相当的孔径,并同时兼有沸石材料良好的热力学稳定性等,因此可用于一些小分子气体的分离领域中。另外,在氢气分离领域中,钯膜由于具有优异的透氢选择性,一直都是研究的热点。本文在结合对现有工艺的分析,提出了适合工业化发展的研究方案,主要内容如下：(1)应用蒸汽相转化涂晶法,在廉价大孔α-Al2O3陶瓷管载体上均匀涂覆晶种,通过二次生长法合成出性能较好的SAPO-34沸石分子筛膜。在气体渗透性能测试中,常温下H2的通量可达6.724×10-6mol·m-2s-1Pa-1,而且氢气的分离选择性H2/CO2、H2/N2、 H2/CH4、H2/C3H8及H2/i-C4H10分别为1.813、7.479、14.337、27.445及54.226。(2)为提高SAPO-34沸石膜分离H2与其他气体分子的分离选择性,本文提出应用化学镀法制备Pd/SAPO-34复合膜。制备得到的复合膜对于氢气的选择性有很大提高,测试温度为573K时,H2/CO2、H2/N2、H2/CH4的选择性分别为65、96、182,H2通量达8.29×10-7 mol·m-2s-1Pa-1;当测试温度为873K时,分离效果达最佳,H2/CO2、H2/N2、H2/CH4的分离选择性分别为182、215、377,H2通量达3.04x10-6mol·m-2s-1Pa-1。(3)在大孔α-Al2O3载体上合成DDR前驱体沸石膜并负载钯膜进行修饰,以提高沸石膜的透氢选择性。在制备DDR沸石膜的过程中为避免发生转晶,缩短沸石膜的合成时间,形成DDR型沸石前驱体膜层,并应用化学镀法制备Pd/DDR-precursor复合膜。当测试温度为873K时,分离效果达到最佳,H2/CO2、H2/N2、H2/CH4的选择性分别为170、185、305,H2通量达1.91×10-6 mol·m-2s-1Pa-1。
[Abstract]:In today's increasingly serious environmental problems, hydrogen, as a green energy, is generally favored. However, hydrogen is a kind of secondary energy, which needs to be prepared by water gas method, petroleum pyrolysis and so on. But these methods also produce by-products such as CO _ 2N _ 2 and some carbohydrates. As a new inorganic membrane material, zeolite membrane has become a hot topic in the field of gas separation. According to the pore structure and pore size, zeolite can be divided into small pores. Mesoporous and macroporous materials, and some microporous zeolites, such as SAPO-34 0.38 x 0.38 nmdr 0.36 x 0.44 nm, have the same pore diameter as some small molecular gases, and also have good thermodynamic stability of zeolite materials, etc. Therefore, it can be used in the field of separation of small molecular gases. In addition, in the field of hydrogen separation, Palladium membrane has been a hot research area because of its excellent hydrogen permeation selectivity. A research scheme suitable for industrial development was put forward. The main contents were as follows: (1) by using steam phase transformation coating method, the crystal seeds were uniformly coated on the carrier of cheap macroporous 伪 -Al 2O 3 ceramic tube. SAPO-34 zeolite membranes with good performance were synthesized by secondary growth method. The H _ 2 flux can reach 6.724 脳 10 ~ (-6) mol 路m ~ (-2) s ~ (-1) Pa-1 at room temperature, and the selectivity of H _ 2 / CO _ (2) O _ (2) H _ (2) N _ (2) N _ (2), H _ 2 / Ch _ (4) C _ (2) C _ (3H _ 8) and H _ (2 / -C _ 4H _ (10)) are 1.813 ~ 7.47914.3327.445 and 54.226.2 respectively) to improve the selectivity of separation of H _ 2 from other gas molecules by SAPO-34 zeolite membrane. In this paper, Pd/SAPO-34 composite membranes were prepared by electroless plating. The hydrogen selectivity of the composite membranes was greatly improved at 573K. The selectivity of H _ 2 / CO _ 2 / H _ 2 / N _ 2H _ 2 / Ch _ 4 was 6.5 脳 10 ~ (-7) mol 路m ~ (-1) 路m ~ (-1) Pa-1 for H _ 2 / H _ 2 / H _ 2 / Ch _ 4, and 8.29 脳 10 ~ (-7) mol 路m ~ (-2) 路m ~ (-1) Pa-1 for H _ 2 / CO _ 2 / H _ 2 / H _ 2 / Ch _ 4 respectively. The separation selectivity of H _ 2 / CO _ 2 / H _ 2 / N _ 2N _ 2 / H _ 2 / Ch _ 4 was 182N _ (2) C _ (2) O _ (2) H _ (2) H _ 2 flux of 3.04x10-6 mol 路m ~ (-2) -1Pa-1.3) DDR precursor zeolite membrane was synthesized on macroporous 伪 -Al _ 2O _ 3 carrier and modified with palladium membrane. In order to improve the hydrogen permeation selectivity of zeolite membrane, in order to avoid transpamination and shorten the synthesis time of zeolite membrane, DDR zeolite precursor membrane was formed in the process of preparing DDR zeolite membrane. The Pd/DDR-precursor composite membrane was prepared by electroless plating. When the test temperature was 873 K, the optimum separation efficiency was obtained. The selectivity of H _ 2 / H _ 2 / H _ 2 / Ch _ 4 was 1. 91 脳 10 ~ (-6) mol m ~ (-2) -2 路s ~ (-1) Pa-1, respectively, and the selectivity of H _ 2 / Ch _ 4 was 1.91 脳 10 ~ (-6) mol ~ (-2) -2s ~ (-1) Pa-1.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.2;TQ051.893

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