Highly stable bilayer MFI zeolite membranes for high temperature hydrogen separation
Highly stable bilayer MFI zeolite membranes for high temperature hydrogen separation
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DOI：
10.1016/j.memsci.2013.08.030
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发表时间：
2014-01
影响因子：
9.5
通讯作者：
Haibing Wang;Xueliang Dong;Y. S. Lin
中科院分区：
文献类型：
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作者：
Haibing Wang;Xueliang Dong;Y. S. Lin
对氢具有渗透选择性的稳定无机膜将在许多重要的工业过程中得到应用，包括用于制氢的水煤气变换反应。本文报道了一种高度稳定的双层MFI沸石膜，具有良好的氢分离特性。该膜由厚（8μm）硅沸石基层上的薄（2μm）ZSM-5层组成，该基层支撑在大孔α-氧化铝上，并具有氧化钇稳定的氧化锆中间阻挡层。通过催化裂化沉积 (CCD) 使 ZSM-5 薄层的沸石孔隙变窄。在500°C时，双层沸石膜表现出约1.2×10−7mol m−2s−1Pa−1的H2渗透性，H2对CO2、CO和H2O蒸气的选择性分别约为23、28和180。在分离测试过程中，随着进料侧压力的增加，该膜显示出稍微改善的分离性能（H2渗透性、H2/CO和H2/CO2选择性）。工业相关模拟气体混合物（25% H2: 25% CO: 25% H2O: 25% CO2，含 400 ppm H2S）在 500 °C 下持续 24 天。由双层沸石膜制成的膜反应器在水煤气变换反应条件下（500°C，H2O/CO=3，GHSV=60,000h−1，使用氧化铈掺杂氧化铁催化剂）在CO转化率、H2回收率以及沸石膜的H2渗透性和选择性方面表现出稳定的性能。双层沸石膜前所未有的热稳定性和化学稳定性以及良好的分离性能与其独特的双层结构和合成方法有关。
Stable inorganic membranes perm-selective to hydrogen will find applications in a number of important industrial processes including water gas shift reaction for hydrogen production. This paper reports a highly stable bilayer MFI zeolite membrane with good hydrogen separation characteristics. The membrane consists of a thin (2 μm) ZSM-5 layer on a thick (8 μm) silicalite base layer supported on macroporous α-alumina with a yttria stabilized zirconia intermediate barrier layer. The zeolitic pores of the thin ZSM-5 layer were narrowed by catalytic cracking deposition (CCD). At 500 °C, the bilayer zeolite membrane exhibits H2permeance of about 1.2×10−7mol m−2s−1Pa−1, with H2to CO2, CO and H2O vapor selectivity respectively of about 23, 28 and 180. The membrane shows slightly improved separation properties (H2permeance, H2/CO and H2/CO2selectivity) as the feed side pressure increases during the test of separation of industrial relevant simulated gas mixture (25% H2: 25% CO: 25% H2O: 25% CO2, with 400 ppm H2S) at 500 °C for 24 days. Membrane reactor made of the bilayer zeolite membrane shows stable performance under water gas shift reaction conditions (500 °C, H2O/CO=3, GHSV=60,000 h−1, with a ceria doped iron oxide catalyst) in terms of CO conversion, H2recovery, and H2permeance and selectivity of the zeolite membrane. The unprecedented thermal and chemical stability and good separation properties of the bilayer zeolite membrane are related to its unique bilayer structure and synthesis methods.