• Title, Summary, Keyword: Hydrogen

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Analysis of Hydrogen Production Cost by Production Method for Comparing with Economics of Nuclear Hydrogen (원자력 수소 경제성 비교를 위한 수소 생산 방법별 생산단가 분석)

  • Lim, Mee-Sook;Bang, Jin-Hwan;Yoon, Young-Seek
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.2
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    • pp.218-226
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    • 2006
  • It can be obtained from hydrocarbon and water, specially production of hydrogen from natural gas is most commercial and economical process among the hydrogen production methods, and has been used widely. However, conventional hydrogen production methods are dependent on fossil fuel such as natural gas and coal, and it may be faced with problems such as exhaustion of fossil fuels, production of greenhouse gas and increase of feedstock price. Thermochemical hydrogen production by nuclear energy has potential to efficiently produce large quantities of hydrogen without producing greenhouse gases. However, nuclear hydrogen must be economical comparing with conventional hydrogen production method. Therefore, hydrogen production cost was analyzed and estimated for nuclear hydrogen as well as conventional hydrogen production such as natural gas reforming and coal gasification in various range.

The Hydrogenation Behaviors of V-xAl (x=1, 5wt.%) Composites by Mechanical Alloying (기계적 합금화법으로 제조한 V-xAl (x=1, 5wt.%) 복합재료의 수소화 반응 거동)

  • Kim, Kyeong-Il;Hong, Tae-Whan
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.4
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    • pp.458-464
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    • 2011
  • Recently, one of the hydrogen production methods has attracted using dense metallic membrane. It has high hydrogen permeation and selectivity which hardly could adopt industrial product because of high cost, hydrogen embrittlment and thermal stability. Meanwhile, vanadium has high hydrogen solubility and it use to instead of Pd-Ag amorphous membrane. Aluminum carried out blocking hydrogen diffusion on grain boundary therefore protecting hydrogen embrittlement. Most of dense metallic membrane is solution diffusion mechanism. The solution diffusion mechanism was very similar hydrogen storing steps such as steps of metal hydride. Thus, V-Al composites were fabricated to use hydrogen induced mechanical alloying. The fabricated V-Al composites were characterized by XRD, SEM, EDS and simultaneous TG/DSC analyses. The hydrogenation behaviors were evaluated using a Sievert's type automatic PCT apparatus. The hydrogenation behaviors of V-Al composites was evaluated too low hydrogen stored capacity and fast hydrogenation kinetics. In PCI results, V-Al composites had low hydrogen solubility, in spite of that, hydrogen kinetics was calculated very fast and hydrogen absorption/desorption contents were same capacity.

Economic Evaluation of Domestic Low-Temperature Water Electrolysis Hydrogen Production (국내 저온수전해 수소생산의 경제성 평가)

  • Gim, Bong-Jin;Kim, Jong-Wook;Ko, Hyun-Min
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.4
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    • pp.559-567
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    • 2011
  • This paper deals with an economic evaluation of domestic low-temperature water electrolysis hydrogen production. We evaluate the economic feasibility of on-site hydrogen fueling stations with the hydrogen production capacity of 30 $Nm^3/hr$ by the alkaline and the polymer electrolyte membrane water electrolysis. The hydrogen production prices of the alkaline water electrolysis, the polymer electrolyte membrane water electrolysis, and the steam methane reforming hydrogen fueling stations with the hydrogen production capacity of 30 $Nm^3/hr$ were estimated as 18,403 $won/kgH_2$, 22,945 $won/kgH_2$, 21,412 $won/kgH_2$, respectively. Domestic alkaline water electrolysis hydrogen production is evaluated as economical for small on-site hydrogen fueling stations, and we need to further study the economic evaluation of low-temperature water electrolysis hydrogen production for medium and large scale on-site hydrogen fueling stations.

Economic Evaluation of Hydrogen Production by Fermentation (발효에 의한 수소생산의 경제성 평가)

  • Gim, Bong-Jin;Kim, Jong-Wook;Park, Sang-Yong
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.2
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    • pp.145-155
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    • 2008
  • This paper deals with an economic evaluation of hydrogen production by fermentation. We evaluate the economic feasibility of domestic hydrogen production by fermentation utilizing glucose and waste water sludge in terms of hydrogen production prices. In addition, we make some sensitivity analysis of hydrogen prices by changing the values of input factors such as the price of glucose, the capital cost of the hydrogen production system, and the hydrogen production yields. The estimated hydrogen prices of the two-step dark-light hydrogen production by fermentation utilizing glucose was $5,347won/kgH_2$, and the single-step hydrogen production by anaerobic fermentation utilizing waste water sludge was $4,255won/kgH_2$, respectively. It is expected that the hydrogen production price by anaerobic fermentation can be reduced if we produce methane or hydrogen utilizing by-products such as alcohols and organic acids, or the government imposes some legal regulations on the treatment of waste water sludge.

Development of an Mg-Based Alloy with a Hydrogen-Storage Capacity over 6 wt% by Adding Graphene

  • Choi, Eunho;Kwak, Young Jun;Song, Myoung Youp
    • Metals and materials international
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    • v.24 no.6
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    • pp.1403-1411
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    • 2018
  • Graphene (multilayer graphene) was chosen as an additive to improve the hydrogen uptake and release properties of magnesium (Mg). Five weight percent of graphene was added to pre-milled Mg by milling in hydrogen (reaction-involving milling). The hydrogen uptake and release properties of the graphene-added Mg were investigated. The activation of Mg-5graphene, which was prepared by adding 5 wt% graphene to Mg pre-milled for 24 h, was completed after the second cycle (cycle number, CN=2). Mg-5graphene had a high effective hydrogen-storage capacity (the quantity of hydrogen absorbed for 60 min) of 6.21 wt% at CN=3 at 593 K in 12 bar $H_2$. At CN=1, Mg-5graphene released 0.46 wt% hydrogen for 10 min and 4.99 wt% hydrogen for 60 min. Milling in hydrogen is believed to create defects (leading to facilitation of nucleation), produce cracks and clean surfaces (leading to increase in reactivity), and decrease particle size (leading to diminution of diffusion distances or increasing the flux of diffusing hydrogen atoms). The added graphene is believed to have helped the sample have higher hydrogen uptake and release rates, weakly but partly, by dispersing heat rapidly.

Analysis of the Economy of Scale for Domestic Steam Methane Reforming Hydrogen Refueling Stations Utilizing the Scale Factor (Scale Factor를 이용한 국내 천연가스 개질식 수소충전소의 규모의 경제 분석)

  • GIM, BONGJIN;YOON, WANG LAI;SEO, DONG JOO
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.3
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    • pp.251-259
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    • 2019
  • The aim of this study is to evaluate the economic feasibility of domestic on-site steam methane reforming (SMR) hydrogen refueling stations. We evaluated the levelized cost of hydrogen (LCOH) for the SMR hydrogen refueling stations, which have production capacities of 100 kg/day (SMR 100), 200 kg/day (SMR 200), and 500 kg/day (SMR 500) utilizing the scale factor. The main results indicated that the LCOH of SMR 100, SMR 200, and SMR 500 were 14,367 won/kg, 11,122 won/kg, and 8,157 won/kg, if the utilizations of hydrogen stations were 70%. These results imply that the production capacity of the domestic SMR hydrogen station should be greater than 500 kg/day to compete with other hydrogen stations when we consider the current sale price of hydrogen at the hydrogen stations.

The Finite Element Analysis on the Characteristics of the Hydrogen Diffusion for the Cr-Mo Steels (Cr-Mo강의 수소확산 특성에 관한 유한요소해석)

  • Lee, Hwi-Won;Ha, Min-Su
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.2
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    • pp.115-121
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    • 2011
  • The size of hydrogen molecule is not so small as to invade into the lattice of material, and therefore, hydrogen invades into the material as atom. Hydrogen movement is done by diffusion or dislocation movement in the near crack tip or plastic deformation. Hydrogen appeared to have many effects on the mechanical properties of the Cr-Mo steel alloys. The materials for this study are 1.25Cr-0.5Mo and 2.25Cr-1Mo steels used at high temperature and pressure. The hydrogen amount obtained by theoretical calculation was almost same with the result solved by finite element analysis. The distribution of hydrogen concentration and average concentration was calculated for a flat specimen. Also, finite element analysis was employed to simulate the redistribution of hydrogen due to stress gradient. The calculation of hydrogen concentration diffused into the material by finite element method will provide the basis for the prediction of delayed fracture of notched specimen. The distribution of hydrogen concentration invaded into the smooth and notched specimen was obtained by finite element analysis. The hydrogen amount is much in smooth specimen and tends to concentrate in the vicinity of surface. Hydrogen embrittlement susceptibility of notched specimen after hydrogen charging is more remarkable than that of smooth specimen.

Analysis of Costs for a Hydrogen Refueling Station in Korea (한국 수소 충전소 건설의 경제성 분석)

  • KANG, BYOUNGWOO;KIM, TAEHYUN;LEE, TAECKHONG
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.3
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    • pp.256-263
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    • 2016
  • As the hydrogen era comes near future, hydrogen fuel cell vehicles are core of hydrogen economy. Until now, Korea has 17 hydrogen refueling stations but 9 hydrogen refueling stations have been retired already and 8 hydrogen refueling stations are still running. With a limited number of hydrogen refueling stations, it is very difficult to get scientific data for the economy of hydrogen refueling stations in Korea. Thus, based on NREL(National Renewable Energy Laboratory) study, we analyzed most recent data for the construction of hydrogen refueling stations in one specific site in Korea. The cost comparison data between Korea and USA shows 14% difference, saying higher costs of Korea. Korea looks 5 years delay compared to USA. This data will be an important tool for the investment from every industrial parties.

Effects of Taeumin Chungsimyeunjatang on the Cerebral neurons injured by Hydrogen Peroxide (태음인(太陰人) 청심연자탕(淸心蓮子湯)이 Hydrogen Peroxide에 손상(損傷)된 백서(白鼠)의 대뇌신경세포(大腦神經細胞)에 미치는 영향(影響))

  • Ok, Yun-young;Ryu, Do-gon;Kim, Kyung-yo
    • Journal of Sasang Constitutional Medicine
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    • v.11 no.2
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    • pp.251-266
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    • 1999
  • 1. Purpose : The purpose of this study was to determine the effects of Chungsimyeunjatang on the cerebral neurons injured by hydrogen peroxide($H_2O_2$). 2. Methods : I observed cell viability in mouse cerebral neurons exposed to hydrogen peroxide by NR assay and MTT assay and determined lipid peroxidation and amounts of LDH release in mouse cerebral neurons exposed to hydrogen peroxide. After administration of Chungsimyeunjatang water extracts, I observed significant changes of cell viability, lipid peroxidation and amounts of LDH release in mouse cerebral neurons exposed to hydrogen peroxide. 3. Results : Hydrogen peroxide showed neurotoxicity. Cell viability in mouse cerebral neurons exposed to hydrogen peroxide decreased in NR assay and MTT assay. Lipid peroxidation and amounts of LDH release in mouse cerebral neurons exposed to hydrogen peroxide increased. Chungsimyeunjatang was very effective in blocking hydrogen peroxide-induced neurotoxicity.

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Effects of ortho-para hydrogen conversion on hydrogen liquefaction performance (Ortho-para 수소변환이 수소액화성능에 미치는 영향)

  • 최항집;강병하;최영돈
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.2
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    • pp.131-139
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    • 2000
  • A direct hydrogen liquefaction equipment has been developed and tested, which consists of a GM refrigerator, a liquefaction vessel, a radiation shield, a cryostat, and an ortho-para converter with catalyst. The effect of ortho-para hydrogen conversion on the performance of hydrogen liquefaction has been investigated. The time needed for the hydrogen liquefaction process with hydrogen pressure charge of 4 atm was delayed to around 75 minutes, and the liquefied mass flow rate of the hydrogen was about 0.0150∼ 0.0205 g/s when the hydrogen was liquefied with the direct hydrogen liquefaction system considering ortho-para conversion. With ortho-para conversion, the liquefied mass flow rate decreased up to 20%. Considering ortho-para conversion, there were up to 30% increase in the work input per unit liquefied mass flow rate. When the ortho-para conversion was considered, FOM decreased to be about 0.031∼0.045.

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