A Highly Efficient Sandwich‐Like Symmetrical Dual‐Phase Oxygen‐Transporting Membrane Reactor for Hydrogen Production by Water Splitting

Abstract

Water splitting coupled with partial oxidation of methane (POM) using an oxygen-transporting membrane (OTM) would be ap otentially ideal way to produce highpurity hydrogen as well as syngas.O ver the past decades, substantial efforts have been devoted to the development of supported membranes with appropriate configurations to achieve considerable performance improvements.H erein, we describe the design of an ovel symmetrical membrane reactor with as andwich-like structure,w hereby al argescale production (> 10 mL min À1 cm À2 )o fh ydrogen and syngas can be obtained simultaneously on opposite sides of the OTM. Furthermore,t his special membrane reactor could regenerate the coke-deactivated catalyst in situ by water steam in as ingle unit. These results represent an important first step in the development of membrane separation technologies for the integration of multiple chemical processes.

Chemical Environment-Induced Mixed Conductivity of Titanate as a Highly Stable Oxygen Transport Membrane

“…When coupling two reactions in an OTM reactor, H 2 either is formed at the membrane surface by light hydrocarbon conversion process or exits on both sides of membrane. To evaluate the chemical stability against reducing atmosphere, SMZ-Ti membranes were treated in H 2 atmosphere, comparing with five typical Co- or Fe-containing OTMs, including BaFe 0.4 Zr 0.2 Co 0.4 O 3−δ (BFZ-Co) (Jiang et al., 2010a, Jiang et al., 2010b), Ba 0.98 Ce 0.05 Fe 0.95 O 3-δ (BC-Fe) (Li et al., 2016), Sm 0.15 Ce 0.85 O 1.925 – Sm 0.6 Sr 0.4 Al 0.3 Fe 0.7 O 3−δ (SDC−SSAFe) (Fang et al., 2016, Li et al., 2017), La 0.9 Ca 0.1 FeO 3−δ (LC-Fe) (Wu et al., 2015), and SrTi 0.75 Fe 0.25 O 3−δ (ST-Fe) (Schulze-Küppers et al., 2015). Figures 1 and S1 depict the X-ray diffraction (XRD) patterns of SMZ-Ti, BFZ-Co, BC-Fe, SDC – SSAFe, LC-Fe, and ST-Fe membranes before and after H 2 treatment.…”

“…At one side of the membrane, hydrogen is obtained from water splitting; meanwhile, at the other side, POM reaction occurs to produce synthesis gas with a H 2 /CO ratio of around 2, which is proper for the subsequent Fischer-Tropsch or methanol production. In addition, some other researchers combine two oxygen-involved reactions at the opposite sides of OTM reactors for two synthesis gases (i.e., H 2 /N 2 and H 2 /CO) production for ammonia and liquid fuel (Li et al., 2016), large-scale hydrogen production (Fang et al., 2016, Li et al., 2017), or CO 2 capture and utilization (Kathiraser et al., 2013, Zhang et al., 2014), further underscoring the promise of OTM reactors for coupling two reactions on the opposite sides.…”

Status of CO<sub>2</sub>-stable dual-phase mixed conductor oxygen permeable membrane materials

“…2018年, Park等人 [127] 利用Tape Casting合成了70vol.% 合的透氧膜, Fang等人 [129] 制备了附着了Ni颗粒的 75CSO-25SSFAO三明治结构透氧膜, 发现该材料能 够实现甲烷部分氧化, 同时在900℃能够获得11.7 mL/(min cm 2 )的透氢量. 随后, Liang 等人 [130] [129] ; (c), (d) 60CSO-40SFMO [130] Figure 8 (Color online) Application of oxygen permeable membranes in coupling reaction of POM/water splitting for hydrogen generation. (a), (b) 75CSO-25SSFAO [129] ; (c), (d) 60CSO-40SFMO [130]…”

Preparation and Property of GDC-LSF Dual-phase Composite Membrane with Straight Pores and Sandwich Structure

“…的形式渗透通过，而氮气和其它气体分子则无法透 过 [1] 。基于陶瓷透氧膜的空气分离制氧技术预期具 有很好的经济和环境效益 [2] ，例如，采用 CO2 作为 透氧膜的吹扫气，制得 O2 与 CO2 的混合气，替代 空气与煤等碳基燃料发生燃烧反应，所得产物含有 高浓度 CO2，便于 CO2 捕获 [3] 。 致密陶瓷透氧膜材料主要为钙钛矿结构过渡金 属氧化物，如 La0.6Sr0.4Co0.2Fe0.8O3-δ [4] ， Ba0.5Sr0.5Co0.8Fe0.2O3-δ [5] 等。这些单相材料虽然氧渗 透通量高，但其化学稳定性和机械强度差 [6] 。与单 相透氧膜相反，由氧离子导体和电子导体构成的双 相复合材料，如 Zr0.84Y0.16O1.92-La0.8Sr0.2Cr0.5Fe0.5O3-δ [7] , Ce0.8Gd0.2O2-δ-La0.8Sr0.2Fe0.8Co0.2O3-δ [8] 等，其稳定性 好，但是氧渗透通量偏低 [9] 。因此，当前陶瓷透氧 膜研发的重点是协调优化膜的氧渗透通量、化学稳 定性和机械强度，以满足实际应用的要求。 陶瓷分离膜主要采用功能层与多孔支撑层相结 合的非对称构型 [10] 。多孔支撑层生胚中通常添加石 墨、淀粉等作为造孔剂，利用干压法、丝网印刷等 方法于多孔支撑层生胚上制备功能层生胚，然后共 烧得到非对称膜 [11][12] 。由于支撑层和功能层共烧时 收缩速率不同，在层间积累应力，常常导致膜片翘 曲 [13] 。如果采用"支撑层-功能层-支撑层"三明治 对称结构，共烧时功能层两侧的界面处均会产生拉 应力，对称的应力分布使膜整体保持平整。Fang 等 [14] 采用流延/ 叠层/ 共烧技术，制备了对称型 Ce0.85Sm0.15O1.925-Sm0.6Sr0.4Al0.3Fe0.7O3-δ 透氧膜，并 将其用于水分解反应与甲烷部分氧化反应相耦合的 膜反应器中。支撑层的孔道多采用石墨等造孔剂烧 蚀得到，曲折度高，不利于气相物质输运，容易出 现浓差极化，限制氧渗透通量的提升。近年来研究 者们开始采用相转化法制备支撑层，其包含沿厚度 方向排列的指状直孔，Meng 等 [4] [16][17] 。氧渗透过程包括气相物质输运、 体扩散和表面氧交换等步骤。由于透氧膜的支撑层 为直孔结构，有利于气相物质传输，有效减小了浓 差极化效应 [4] 。致密层厚度较薄(~80 μm)，有效降 低了体扩散阻力。因此，对于未修饰样品，表面氧 交换很可能是氧渗透的速率决定步骤。对于 NNO 修饰的样品，其氧渗透通量远大于未修饰样品，前 者的表观活化能则远小于后者。显然，NNO 纳米粒 子修饰促进了表面氧交换。 图 5 氧渗透通量的阿伦尼乌斯曲线…”