Fabrication and Performance Characterization of Pd/BaZrO3-based Cermet Membranes for Hydrogen Separation
- 주제(키워드) Membrane , cermet , hydrogen , separation
- 발행기관 고려대학교 대학원
- 지도교수 이종흔
- 지도교수 이종호
- 발행년도 2014
- 학위수여년월 2014. 2
- 학위구분 석사
- 학과 일반대학원 신소재공학과
- 원문페이지 76 p
- 실제URI http://www.dcollection.net/handler/korea/000000048329
- 본문언어 영어
- 제출원본 000045793229
초록/요약
Using hydrogen as an energy source could get a lot of attention related to global climate change, energy crisis and global warming. Hydrogen transport membranes have been of interest for the last several decades because of their possible application for separating hydrogen. These membrane separation is non-galvanic (i.e. it does not use electrodes or an external power supply to drive the separation), and hydrogen separation from the feed stream is of high purity, so post-separation steps are unnecessary. This will require that membrane material with suitable protonic and electronic conductivities as well as high hydrogen solubility and diffusivity. Moreover, this membrane must be thin dense for high hydrogen selectivity and permeability. Numerous cerate and zirconate perovskite oxides have been reported to have reasonable proton conductivity in hydrogen-rich and humid atmosphere, particularly at high temperature when they are doped with a rare earth ion. However, it is difficult to provide sufficient protonic and electronic conductivity for high hydrogen permeation flux. To increase the electronic conductivity, and thereby increase the hydrogen permeability, various dense cermet membranes were developed. In these cermet membranes, the metal enhances the hydrogen permeability of the ceramic phase by increasing the electronic conductivity of the composite. If use the hydrogen transport metal, which has high hydrogen permeability, it provides an additional transport path for hydrogen. In this study, hydrogen permeation membranes were fabricated from cermet containing Ba(Ce0.9Y0.1)O3-δ (BCY) and Ba(Zr0.84Y0.14Cu0.01)O3-δ (BZYCu) as a proton-conducting ceramic phase and Pd as the hydrogen transport metal. A disk of membranes were prepared by cold isostatic pressing of Pd-BZYCu composite powder synthesized by glycine nitrate process and subsequent sintering at 1500oC for 10 hours in nitrogen atmosphere. The hydrogen permeation rate has been measured with a gas chromatograph (GC) as a function of temperature (700-850oC) and hydrogen partial pressure difference. To reduce the membrane thickness, we fabricated these cermet membranes (50vol% Pd with BZYCu) with thickness of ~10㎛ were prepared by conventional paste painting and co-sintering techniques on a porous substrate. The chemical and thermal stability of Pd-BZYCu membranes were also investigated under various environmental conditions considering practical usage of cermet membrane under mixed hydrocarbon gas atmosphere.
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Contents
Abstract ⅰ
Contents ⅳ
List of Figures ⅴ
List of Tables ⅶ
1. Introduction 1
2. Experimental 9
2-1. Synthesis and fabrication of cermet 9
2-2. Characterizations of cermet membranes (bulk) 13
2-3. Fabrication of thin film membranes 15
2-3-1. BZYCu substrates 15
2-3-2. Pd (50 vol%)-BZYCu (50 vol%) thin film 15
2-4. Hydrogen permeation test 16
3. Result and Discussion 21
3-1. Effect of hydrogen transport metal in Pd-BCY cermet membrane 21
3-2. Optimization of microstructure of Pd-BZYCu cermet membrane 28
3-3. Hydrogen permeation test 49
3-3-1. Effect of Pd (metallic phase) content 49
3-3-2. Effect of thickness 53
3-3-3. Membrane stability 55
3-4. Thin film properties 58
4. Conclusion 62
5. References 63
