• Title/Summary/Keyword: hydrogen separation

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Gas Separation Membranes - Current Status

  • Puri, Pushpinder S.
    • Membrane Journal
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    • v.6 no.3
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    • pp.117-126
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    • 1996
  • Membrane-based gas separation systems are now widely accepted and employed as unit operation in industrial gas, chemical, and allied industries. Following their successful commercialization in the late seventies to recover hydrogen from ammonia purge gas streams, membrane-based systems have gained acceptance in a wide variety of applications. Numerous systems are in operation today to: recover hydrogen from other purge gas and hydrocarbon streams; adjust the $H_{2}/CO$ ratio in syngas; remove $CO_{2}$ from natural gas; recover helium; dry gas streams; and separate air. Lower cost, ease of operation, operational flexibility and portability are a few of the reasons membrane-based systems are chosen over absorption and cryogenic-based separations in certain applications.

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Study on Electrochemical Hydrogen Separation of Hydrogen and Nitrogen Mixture Gas (수소와 질소 혼합 가스의 전기화학적 수소 분리에 관한 연구)

  • DONGYUN KIM;TEAHEON KIM;DONGKEUN LEE;YOUNGSANG KIM;KOOKYOUNG AHN;YONGGYUN BAE;JINYOUNG PARK;YOUNG KIM
    • Journal of Hydrogen and New Energy
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    • v.34 no.2
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    • pp.149-154
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    • 2023
  • In the Fourth Industrial Revolution, hydrogen energy is in the spotlight. There is a difficulty in commercialization due to the lack of hydrogen infrastructure. Therefore, a lot of hydrogen should be imported and a method using ammonia is the most useful. In this study, using the mixed gas of hydrogen and nitrogen generated when ammonia is decomposed, the hydrogen separation performance is to be tested. Hydrogen was separated using an electrochemical hydrogen compressor based on a fuel cell and the experiment was conducted by changing the ratio of hydrogen and nitrogen. In addition, the performance was also compared by the difference both the pressure and the membrane.

Effects of Operating Variables on Separation Rate and Separation Efficiency in Ash Separator for Solid Fuel Chemical Looping Combustor (고체연료 매체순환연소기를 위한 회재분리기에서 분리속도 및 분리효율에 미치는 조업변수들의 영향)

  • RYU, HOJUNG;LEE, DONGHO;YOON, JOOYOUNG;JANG, MYOUNGSOO;BAE, DALHEE;PARK, JAEHYEON;BAEK, JEOMIN
    • Journal of Hydrogen and New Energy
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    • v.27 no.2
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    • pp.211-219
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    • 2016
  • To develop an ash separator for the solid fuel chemical looping combustion system, effects of operating variables such as solid injection nozzle velocity, diameter of solid injection nozzle, gap between solid injection line and vent line, vent line inside diameter, and solid intake height on solid separation rate and solid separation efficiency were measured and discussed using heavy and coarse particle and light and fine particles mixture as bed material in an acrylic fluidized bed apparatus. The solid separation rate increased as the solid injection nozzle velocity and the diameter of solid injection nozzle increased. However, the solid separation rate decreased as the gap between solid injection line and vent line, the vent line inside diameter, and the solid intake height increased. The solid separation efficiency was in inverse proportion to the solid separation rate. In this study, we could get high solid separation rate up to 2.39 kg/hr with 91.6% of solid separation efficiency.

Analysis of Thermal Flow Characteristics according to the Opening Ratio of High-Pressure Valve for Hydrogen Storage Tank (수소 저장 탱크용 고압 밸브의 개도율에 따른 열·유동 특성 분석)

  • JUNG, DA WOON;CHOI, JIN;SUH, HYUN KYU
    • Journal of Hydrogen and New Energy
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    • v.33 no.5
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    • pp.525-533
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    • 2022
  • In this study, in order to numerically analyze the heat flow characteristics in the valve according to the opening rate for the solenoid valve for hydrogen supply applied to the hydrogen storage tank, flow characteristics were comparatively analyzed. Through the analysis of pressure and temperature distributions within the valve according to the high-pressure supply condition of 70 MPa or more, the heat flow characteristics in the valve, inlet and outlet passage according to the opening rate of the valve were identified. As a result a sudden change in the fluid behavior appears in the neck region of the valve, and it is understood that the flow separation caused by the flow path shape of the expanded tube has a dominant influence on the flow characteristics. And, it was confirmed that the shape of the valve seat is a factor significantly affecting the improvement of flow rate and differential pressure performance.

The Comparison of Bunsen Reaction With Phase Separation in Sulfur-lodine Thermochemical Hydrogen Production Process (황-요오드 열화학 수소 제조 공정에서 분젠 반응과 상 분리 비고)

  • Lee, Kwang-Jin;Ahn, Sueng-Hyuk;Kim, Young-Ho;Park, Chu-Sik;Bae, Ki-Kwang
    • Journal of Hydrogen and New Energy
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    • v.19 no.2
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    • pp.111-117
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    • 2008
  • A Bunsen reaction section is a primary stage of Sulfur-iodine thermochemical hydrogen production cycle. This section is important, because it decides the efficiency of next stages. In order to produce hydrogen very efficiently, the characteristics of Bunsen reaction were investigated via two experimental methods. The one is a phase separation of $H_2SO_4-HI-H_2O-I_2$ mixture system, and the other is a direct Bunsen reaction. The characteristics of each method were investigated and compared. As the result of this study, the amount of HI and $I_2$ in $H_2SO_4$ phase via Bunsen reaction was more decreased than that via $H_2SO_4-HI-H_2O-I_2$ mixture system with increasing $I_2$ concentration. However, the amount of $H_2SO_4$ in $HI_x$ phase via Bunsen reaction was remarkably increased with increasing $I_2$ concentration, while that via $H_2SO_4-HI-H_2O-I_2$ mixture system was decreased. On the other hand, the range of initial composition which is able to separate into two liquid phases without $I_2$ solidification was almost alike.

A Review of Electrochemical Hydrogen Compressor Technology (전기화학적 수소 압축기 기술)

  • KIM, SANG-KYUNG
    • Journal of Hydrogen and New Energy
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    • v.31 no.6
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    • pp.578-586
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    • 2020
  • There is growing interest worldwide in a hydrogen economy that uses hydrogen as an energy medium instead of hydrocarbon-based fossil fuels as a way to combat climate change. Since hydrogen has a very low energy density per unit volume at room temperature, hydrogen must be compressed and stored in order to use as an energy carrier. There are mechanical and non-mechanical methods for compressing hydrogen. The mechanical method has disadvantages such as high energy consumption, durability problems of moving parts, hydrogen contamination by lubricants, and noise. Among the non-mechanical compression methods, electrochemical compression consumes less energy and can compress hydrogen with high purity. In this paper, research trends are reviewed, focusing on research papers on electrochemical hydrogen compression technology, and future research directions are suggested.

Hydrogen Permeation Performance of Ni48Nb32Zr20 Alloy Membrane Coated with Pd by Sputtering (스퍼터링으로 Pd가 코팅된 Ni48Nb32Zr20 합금분리막의 수소 투과 성능)

  • Min Chang Shin;Jung Hoon Park
    • Membrane Journal
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    • v.34 no.2
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    • pp.140-145
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    • 2024
  • In modern times, when a change in the energy paradigm is required, hydrogen is an attractive energy source. Among these hydrogen purification technologies, technology using a membrane is attracted attention as a technology that can purify high purity hydrogen at low cost. However, palladium(Pd), which is mostly used because of its excellent hydrogen separation performance, is very expensive, so a replacement material is needed. In this study, a alloy membrane was manufactured from an alloy of niobium (Nb), which has high hydrogen permeability but is weak to hydrogen embrittlement, and nickel (Ni) and zirconium (Zr), which have low hydrogen permeability but are highly durable. Hydrogen permeation characteristics were confirmed under conditions of 350~450 ℃ at 1 to 4 bar. The maximum hydrogen permeation flux was 0.69 ml/cm2/min for the Ni48Nb32Zr20 alloy membrane without Pd coating, and 13.05 ml/cm2/min for the Pd coated alloy membrane.

Preparation and Gas Permeation Characteristics of Polyetherimide Hollow Fiber Membrane for the Application of Hydrogen Separation (수소분리를 위한 Polyetherimide계 고분자 중공사막의 제조 및 기체투과 특성)

  • Kwon, Hyeon Woong;Im, Kwang Seop;Kim, Ji Hyeon;Kim, Seong Heon;Kim, Do Hyeong;Nam, Sang Yong
    • Membrane Journal
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    • v.31 no.6
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    • pp.456-470
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    • 2021
  • In this study, polyetherimide-based hollow fiber membranes were manufactured using the NIPS (nonsolvent induced phase separation) method. THF, Ethanol, and LiNO3 were used as additives to control the morphology of the PEI-hollow fiber membranes. Furthermore, for the development of a high hydrogen separation membrane, the spinning conditions were optimized through the characterization of SEM and gas permeance. As a result, as the content of THF increased, the hydrogen/carbon dioxide selectivity increased. However, the permeance decreased due to the trade-off relationship. When ethanol was added, a finger-like structure was shown, and when LiNO3 was added, a sponge structure was shown. In particular, in the case of a hollow fiber membrane with an optimized PDMS coating layer, the permeance was 40 GPU and the hydrogen/carbon dioxide selectivity was 5.6.