• Title/Summary/Keyword: Hydrogen energy storage system

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HEAT-UP AND COOL-DOWN TEMPERATURE-DEPENDENT HYDRIDE REORIENTATION BEHAVIORS IN ZIRCONIUM ALLOY CLADDING TUBES

  • Won, Ju-Jin;Kim, Myeong-Su;Kim, Kyu-Tae
    • Nuclear Engineering and Technology
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    • v.46 no.5
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    • pp.681-688
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    • 2014
  • Hydride reorientation behaviors of PWR cladding tubes under typical interim dry storage conditions were investigated with the use of as-received 250 and 485ppm hydrogen-charged Zr-Nb alloy cladding tubes. In order to evaluate the effect of typical cool-down processes on the radial hydride precipitation, two terminal heat-up temperatures of 300 and $400^{\circ}C$, as well as two terminal cool-down temperatures of 200 and $300^{\circ}C$, were considered. In addition, two cooling rates of 2.5 and $8.0^{\circ}C/min$ during the cool-down processes were taken into account along with zero stress or a tensile hoop stress of 150MPa. It was found that the 250ppm hydrogen-charged specimen experiencing the higher terminal heat-up temperature and the lower terminal cool-down temperature generated the highest number of radial hydrides during the cool-down process under 150MPa hoop tensile stress, which may be explained by terminal solid hydrogen solubilities for precipitation, and dissolution and remaining circumferential hydrides at the terminal heat-up temperatures. In addition, the slower cool-down rate generates the larger number of radial hydrides due to a cooling rate-dependent, longer residence time at a relatively high temperature that can accelerate the radial hydride nucleation and growth.

R&D Trends and Unit Processes of Hydrogen Station (수소 스테이션의 연구개발 동향 및 단위공정 기술)

  • Moon, Dong Ju;Lee, Byoung Gwon
    • Korean Chemical Engineering Research
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    • v.43 no.3
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    • pp.331-343
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    • 2005
  • Development of hydrogen station system is an important technology to commercialize fuel cells and fuel cell powered vehicles. Generally, hydrogen station consists of hydrogen production process including desulfurizer, reformer, water gas shift (WGS) reactor and pressure swing adsorption (PSA) apparatus, and post-treatment process including compressor, storage and distributer. In this review, we investigate the R&D trends and prospects of hydrogen station in domestic and foreign countries for opening the hydrogen economy society. Indeed, the reforming of fossil fuels for hydrogen production will be essential technology until the ultimate process that may be water hydrolysis using renewable energy source such as solar energy, wind force etc, will be commercialized in the future. Hence, we also review the research trends on unit technologies such as the desulfurization, reforming reaction of fossil fuels, water gas shift reaction and hydrogen separation for hydrogen station applications.

Comparison of the Internal Pressure Behavior of Liquid Hydrogen Fuel Tanks Depending on the Liquid Hydrogen Filling Ratio (액체수소 충전 비율에 따른 액체수소 연료탱크의 내부 압력 거동 비교)

  • Dongkuk Choi;Sooyong Lee
    • Journal of Aerospace System Engineering
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    • v.18 no.3
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    • pp.8-16
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    • 2024
  • Because hydrogen has very low density, a different storage method is required to store the same amount of energy as fossil fuel. One way to increase the density of hydrogen is through liquefaction. However, since the liquefied temperature of hydrogen is extremely low at -252 ℃, it is easily vaporized by external heat input. When liquid hydrogen is vaporized, a self-pressurizing phenomenon occurs in which the pressure inside the hydrogen tank increases, so when designing the tank, this rising pressure must be carefully predicted. Therefore, in this paper, the internal pressure of a cryogenic liquid fuel tank was predicted according to the liquid hydrogen filling ratio. A one-dimensional thermodynamic model was applied to predict the pressure rise inside the tank. The thermodynamic model considered heat transfer, vaporization of liquid hydrogen, and fuel discharging. Finally, it was confirmed that there was a significant difference in pressure behavior and maximum rise pressure depending on the filling ratio of liquid hydrogen in the fuel tank.

A Heat Exchanging Characteristics of Organic Rankine Cycle for Waste Heat Recovery of Coal Fired Power Plant (화력발전용 복수기 폐열 회수를 위한 유기랭킨사이클 시스템 열교환 특성 해석)

  • Jeong, Jinhee;Im, Seokyeon;Kim, Beomjoo;Yu, Sangseok
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.1
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    • pp.64-70
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    • 2015
  • Organic Rankine cycle (ORC) is an useful cycle for power generation system with low temperature heat sources ($80{\sim}400^{\circ}C$). Since the boiling point of operating fluid is low, the system is used to recover the low temperature heat source of waste heat energy. In this study, a ORC with R134a is applied to recover the waste energy of condenser of coal fired power plant. A system model is developed via Thermolib$^{(R)}$ under Simulink/MATLAB environment. The model is composed of a refrigerant heat exchanger for heat recovery from coal fired condenser, a drum, turbine, heat exchanger for ORC heat rejection, storage tank, water recirculation pump and water drip pump. System analysis parameters were heat recovery capacity, type of refrigerants, and types of turbines. The simulation model is used to analyze the heat recovery capacity of ORC power system. As a result, increasing the overall heat transfer coefficient to become the largest of turbine power is the most economical.

Ammonia Decomposition over Ni Catalysts Supported on Zeolites for Clean Hydrogen Production (청정수소 생산을 위한 암모니아 분해 반응에서 Ni/Zeolite 촉매의 반응활성에 관한 연구)

  • Jiyu Kim;Kyoung Deok Kim;Unho Jung;Yongha Park;Ki Bong Lee;Kee Young Koo
    • Journal of the Korean Institute of Gas
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    • v.27 no.3
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    • pp.19-26
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    • 2023
  • Hydrogen, a clean energy source free of COx emissions, is poised to replace fossil fuels, with its usage on the rise. Despite its high energy content per unit mass, hydrogen faces limitations in storage and transportation due to its low storage density and challenges in long-term storage. In contrast, ammonia offers a high storage capacity per unit volume and is relatively easy to liquefy, making it an attractive option for storing and transporting large volumes of hydrogen. While NH3 decomposition is an endothermic reaction, achieving excellent low-temperature catalytic activity is essential for process efficiency and cost-effectiveness. The study examined the effects of different zeolite types (5A, NaY, ZSM5) on NH3 decomposition activity, considering differences in pore structure, cations, and Si/Al-ratio. Notably, the 5A zeolite facilitated the high dispersion of Ni across the surface, inside pores, and within the structure. Its low Si/Al ratio contributed to abundant acidity, enhancing ammonia adsorption. Additionally, the presence of Na and Ca cations in the support created medium basic sites that improved N2 desorption rates. As a result, among the prepared catalysts, the 15 wt%Ni/5A catalyst exhibited the highest NH3 conversion and a high H2 formation rate of 23.5 mmol/gcat·min (30,000 mL/gcat·h, 600 ℃). This performance was attributed to the strong metal-support interaction and the enhancement of N2 desorption rates through the presence of medium basic sites.

Electrochemical Characteristics of Hybrid Cell Consisting of Li Secondary Battery and Supercapacitor (리튬이차전지와 슈퍼커패시터로 구성된 하이브리드 셀의 전기화학적 특성)

  • KIM1, SANGGIL;GIL, BOMIN;HWANG, GABJIN;RYU, CHEOLHWI
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.1
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    • pp.43-48
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    • 2019
  • This study investigates the electrochemical characteristics of the hybrid cell that combined the advantageous characteristics of Li secondary battery and supercapacitor, high energy density and high power density, respectively. Electrochemical behaviors of the hybrid cell was characterized by charge/discharge, cycle and impedance tests. The hybrid cell using Li secondary battery and supercapacitor had better discharge capacity and cycle performance than that of using Li secondary battery only. Proper design of such a hybrid cell system is expected to result in substantial benefits to the well being of the Li secondary battery. The hybrid cell involving Li secondary battery for high energy density and supercapacitor for high power density may be the possible solution for future energy storage system.

Ammonia-fueled Solid Oxide Fuel Cell Recirculation Systems for Power Generation (암모니아 활용 고체산화물 연료전지 재순환 발전 시스템)

  • JIN YOUNG PARK;THAI-QUYEN QUACH;JINSUN KIM;YONGGYUN BAE;DONGKEUN LEE;YOUNGSANG KIM;SUNYOUP LEE;YOUNG KIM
    • Transactions of the Korean hydrogen and new energy society
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    • v.35 no.1
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    • pp.40-47
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    • 2024
  • Ammonia is drawing attention as carbon free fuel due to its ease of storage and transportation compared to hydrogen. This study suggests ammonia fueled solid oxide fuel cell (SOFC) system with electrochemical hydrogen compressor (EHC)-based recirculation. Performance of electrochemical hydrogen pump is based on the experimental data under varying hydrogen and nitrogen concentration. As a result, the suggested system shows 62.04% net electrical efficiency. The efficiency is 10.33% point higher compared to simple standalone SOFC system (51.71%), but 0.02% point lower compared to blower-based recirculation system (62.06%). Further improvement in the EHC-based SOFC recirculation system can be achieved with EHC performance improvement.

Research Trend and Analysis of Altitude and Endurance for Fuel Cell Unmanned Aerial Vehicles (연료전지 무인항공기의 고도와 체공시간에 대한 특성 분석 및 최신 연구동향)

  • Cho, Seonghyun;Kim, Minjin;Son, Youngjun;Yang, Taehyun
    • Transactions of the Korean hydrogen and new energy society
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    • v.25 no.4
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    • pp.393-404
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    • 2014
  • Unmanned aerial vehicles (UAVs) have been applied to not only military missions like surveillance and reconnaissance but also commercial missions like meteorological observation, aerial photograph, communication relay, internet network build and disaster observation. Fuel cells make UAVs eco-friendly by using hydrogen. Proton exchange membrane fuel cells (PEMFCs) show low operation temperature, high efficiency, low noise and high energy density and those characterisitcs are well fitted with UAVs. Thus Fuel cell based UAVs have been actively developed in the world. Recently, fuel cell UAVs have started to develope for high altitude UAVs because target altitude of UAVs is expanded upto stratosphere altitude. Long endurance of UAVs is essential to improve effects of the missions. Improvement of UAV endurance time could be fulfilled by developing a hydrogen fuel storage system with high energy density and reducing the weight of UAVs. In this paper, research trend and analysis of fuel cell UAVs are introduced in terms of their altitude and endurance time and then the prospect of fuel cell UAVs are shown.

A World Trend of Hydrogen Energy Policy and Patent Analysis on the Hydrogen Compressor (수소 에너지 정책의 세계동향 및 수소 압축기의 특허분석)

  • Shim, Kyu-Jin;Kong, Tae-Woo;Lee, Yong-Hun;Chung, Han-Shik;Jeong, Hyo-Min
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.179-185
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    • 2005
  • Nowadays, study about hydrogen fuel which consist of hydrogen extraction process, reforming, fuel cell equipment, and receptacle are flourish all over the world. Currently, Korea hydrogen station is still underdevelopment. Yet the most important part such as hydrogen compressor has not been develop. Therefore, if the high pressure compressor for hydrogen have been developed by domestic technology. In the future many benefit can be gain instead of importing. Such as many hydrogen station can be built in Korea, and also Korea will be able to provide hydrogen system for worldwide. This study is going to analysis hydrogen compressor in order to store high pressure hydrogen. This is almost approach practical use of tile hydrogen storage method.

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Poly(arylene ether ketone) block copolymer prepared through sulfonation process for polymer electrolyte membrane fuel cell (술폰화 공정을 통해 제조한 고분자 전해질형 연료전지용 폴리(아릴렌 이서 케톤) 블록 코폴리머)

  • Jang, Hyeri;Nahm, Keesuk;Yoo, Dongjin
    • Journal of Energy Engineering
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    • v.25 no.3
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    • pp.66-72
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    • 2016
  • In this study, a sulfonated poly(arylene ether ketone) block copolymer was prepared from hydrophilic oligomer and hydrophobic oligomer. The structure of the prepared membrane was characterized by $^1H$-NMR, FT-IR and GPC. The $M_w$(weight-average molecular weights) of the polymer was $209,700g\;mol^{-1}$ and the molecular weight distribution($M_w/M_n$) of 1.25 was obtained. The prepared membrane showed excellent thermal stability with gradual weight loss up to $200^{\circ}C$. The proton conductivity of SPAEK block copolymer reached the maximum of $9.0mS\;cm^{-1}$ at $90^{\circ}C$ under 100% relative humidity (RH). From the observed results, it is necessary to do more aggressive attempt to study the possibility of application as an ion-conductive composite electrolyte.