• Title, Summary, Keyword: Hydrogen

Search Result 10,971, Processing Time 0.054 seconds

Study on the Hydrogen Delayed Fracture Property of TRIP Steel by Slow Strain Rate Testing Method (일정 변형률 시험에 의한 TRIP강의 수소 지연파괴 특성연구)

  • Cho, J.H.;Lee, J.K.
    • Corrosion Science and Technology
    • /
    • v.10 no.4
    • /
    • pp.131-135
    • /
    • 2011
  • The demands of high-strength steel have been steadily increased to reduce the weight of vehicles. Although the TRIP steel has been the promising candidate material for the purpose, high strength hinders the application due to the susceptibility to hydrogen delayed fracture in the corrosive environment. Moreover, the testing method was not specified in the ISO standards. In this work, the test method to evaluate the susceptibility of hydrogen delayed fracture was studied by slow strain rate testing technique. The four test experimental parameters were studied : strain rate, hydrogen charging time, holding time after hydrogen charging, and holding time after cadmium plating. The steel was fractured by hydrogen in case the strain rate was in the range of $1{\times}10^{-4}{\sim}5{\times}10^{-7}/sec$. It was confirmed that the slow strain rate test is effective method to evaluate the susceptibility to hydrogen delayed fracture. The holding time over 24 hrs after hydrogen charging, nullified the hydrogen effect, that is, the specimen was no more susceptible to hydrogen after 24 hrs even though the specimen was fully hydrogen-charged. Moreover, cadmium electroplating could not prevent from diffusing out the hydrogen from the steel in the experiment. The effective experimental procedures were discussed.

Economic Evaluation of Domestic Photoelectrochemical Hydrogen Production (국내 광전기화학 수소생산의 경제성 평가)

  • Gim, Bong-Jin;Kim, Jong-Wook
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.21 no.1
    • /
    • pp.64-71
    • /
    • 2010
  • This paper deals with an economic evaluation of domestic immersing type photoelectrochemical hydrogen production. We also make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the initial capital cost, the solar to hydrogen conversion efficiency, and the system duration time. The hydrogen production price of the immersing type photoelectrochemical system was estimated as 8,264,324 won/$kgH_2$. It is expected that the production cost by photoelectrochemical hydrogen production can be reduced to 26,961 won/$kgH_2$ if the solar to hydrogen conversion efficiency is increased to 14%, the system duration time is increased to 20,000 hours, and the initial capital cost is decreased to 10% of the current level. The photoelectrochemical hydrogen production is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen conversion efficiency and the system duration time as well as to reduce prices of the system facilities.

Preliminary cost estimation for large-scale nuclear hydrogen production based on SI process (초고온가스원자로 열원 SI 공정을 이용한 원자력수소생산시스템 비용 예비 분석)

  • Yang, Kyoung-Jin;Choi, Jae-Hyuk;Lee, Ki-Young;Lee, Tae-Hoon;Lee, Kyoung-Woo;Kim, Mann-Eung
    • 한국신재생에너지학회:학술대회논문집
    • /
    • /
    • pp.723-726
    • /
    • 2009
  • As a preliminary study of cost estimates for nuclear hydrogen systems, the hydrogen production costs of the nuclear energy sources benchmarking GT-MHR are estimated in the necessary input data on a Korean specific basis. G4-ECONS developed by EMWG of GIF in 2008 was appropriately modified to calculate the cost for hydrogen production of SI process with VHTR as a thermal energy source rather than the LUEC. The estimated costs presented in this paper show that hydrogen production by the VHTR could be competitive with current techniques of hydrogen production from fossil fuels if $CO_2$ capture and sequestration is required. Nuclear production of hydrogen would allow large-scale production of hydrogen at economic prices while avoiding the release of $CO_2$. Nuclear production of hydrogen could thus become the enabling technology for the hydrogen economy. The major factors that would affect the cost of hydrogen were also discussed.

  • PDF

A experimental study on the sensor response at hydrogen leakage in a residential fuel cell system (가정용 연료전지 시스템 내부 수소 누출 시 센서 응답 특성에 관한 연구)

  • Kim, Young-Doo;Chung, Tae-Yong;Shin, Dong-Hoon;Nam, Jin-Hyun;Kim, Young-Gyu
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.2009-2014
    • /
    • 2007
  • Hydrogen is a fuel of fuel cell system, which has powerful explosion possibility. Hence, the fuel cell system needs safety evaluation to prevent risk of hydrogen leakage. We use a actual size chamber of a common fuel cell module to analyze hydrogen. Hydrogen injection holes are located in lower part of the chamber in order to simulated hydrogen leakage. The hydrogen sensor can detect range of 0${\sim}$4%. Since the hydrogen gas, of which leaked amount is controled by MFC, are injected at the bottom holes, the transient sensor signals are measured. At a condition of 10cc/s of hydrogen leakage, the sensor detects hydrogen leakage after 22sec and there is also several seconds of time delay depending on the position of the sensor. This experimental data can be applied for the design of the hydrogen detection system and ventilation system of a residential fuel cell system.

  • PDF

A Construction Plan of Hydrogen Fueling Stations on Express Highways Using Geographic Information System (지리정보시스템을 이용한 고속국도에서의 수소충전소 구축 방안)

  • Gim, Bongjin;Kook, Ji Hoon;Cho, Sang Min
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.25 no.3
    • /
    • pp.255-263
    • /
    • 2014
  • This paper deals with a construction plan of hydrogen fueling stations on express highways using geographic information system. We analyzed the existing hydrogen fueling stations and production facilities to construct the hydrogen supply system to satisfy the hydrogen demands. Also, we suggested the necessary number and locations of hydrogen fueling stations on express highways for operating fuel cell vehicles. As a result, we need to construct at least 6 hydrogen stations on express highways in 2020 and 14 hydrogen stations in 2025. In 2030, when fuel cell vehicles are expected to spread over the whole nation, 114 hydrogen stations are needed to construct on express highways. This study mainly utilized the information of distances between hydrogen production facilities and fueling stations. However, we need to analyze the other factors such as traffic and income data. Also, it is necessary to make a suitable construction plan of hydrogen fueling stations that should be constructed on each district using geographic information system.

Calculation and Comparison of Thermodynamic Properties of Hydrogen Using Equations of State for Compressed Hydrogen Storage (상태방정식을 이용한 고압수소 저장을 위한 수소 열역학 물성 계산 및 비교)

  • PARK, BYUNG HEUNG
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.31 no.2
    • /
    • pp.184-193
    • /
    • 2020
  • One of the technical methods to increase the volumetric energy density of hydrogen is to pressurize the gaseous hydrogen and then contain it in a rigid vessel. Especially for automotive systems, the compressed hydrogen storage can be found in cars as well as at refueling stations. During the charging the pressurized hydrogen into a vessel, the temperature increases with the amount of stored hydrogen in the vessel. The temperature of the vessel should be controlled to be less than a limitation for ensure stability of material. Therefore, the accurate estimation of temperature is of significance for safely storing the hydrogen. In this work, three well-known cubic equations of state (EOSs) were adopted to examine the accuracy in regenerating thermodynamic properties of hydrogen within the temperature and pressure ranges for the compressed hydrogen storage. The formulations representing molar volume, internal energy, enthalpy, and entropy were derived for Redlich-Kwong (RK), Soave-Redlioch-Kwong (SRK), and Peng-Robinson (PR) EOSs. The calculated results using the EOSs were compared with literature data given by NIST. It was revealed that the accuracies of RK and SRK EOSs were satisfactorily compatible and better than the results by PR EOS.

An Investigation of Combustion and EmissionCharacteristics in Heavy-Duty Hydrogen-CNG Engine (중대형 수소-천연가스 기관의 수소혼합율 변화에 대한 연소 및 배기특성)

  • LIM, H.S.;KIM, Y.Y.;LEE, J.T.
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.14 no.3
    • /
    • pp.276-282
    • /
    • 2003
  • A hydrogen enriched CNG engine can be stably operated at ultra lean condition and reduce emission extremely. It also has advantage to increase gradually the use of hydrogen for the coming hydrogen-energy age. In this studies, the combustion and emission characteristics of heavy-duty hydrogen-CNG engine were investigated to verify the enhancement of performance by enriched hydrogen into natural gas. The results showed that a hydrogen-CNG engine could achieve ultra lean operation and low emission, while power was reduced by the decrease of intake air flow.

Simulation of Temperature Behavior in Hydrogen Tank During Refueling Using Cubic Equations of State (3차 상태방정식을 이용한 수소 충전 온도 거동 모사)

  • PARK, BYUNG HEUNG
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.30 no.5
    • /
    • pp.385-394
    • /
    • 2019
  • The analysis of temperature behavior of a hydrogen tank during refueling is of significance to clarify the safety of the compressed hydrogen storage in vehicles since the temperature at a tank rises with inflow of hydrogen. A mass balance and an energy balance were combined to obtain analytical model for temperature change during the hydrogen refueling. The equation was coupled to Peng-Robinson-Gasem (PRG) equation of state (EOS) for hydrogen. The PRG EOS was adopted after comparison with other four different cubic EOSs. A parameter of the model was determined to fit data from experiments of various inlet flow rates and temperatures. The temperature and pressure change with refueling time were obtained by the developed model. The calculation results revealed that the extent of precooling was more effective than the flow rate control.

Hydrogen Evolution Properties of Alanate-based Hydrogen Storage Materials (알라네이트 계 수소 저장 물질의 수소 방출 특성)

  • JEONG, HEONDO
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.28 no.4
    • /
    • pp.361-368
    • /
    • 2017
  • Alanate-based materials, which were known to have high hydrogen storage capacity, were synthesized by mechanochemically metathesis reaction of metal chloride and sodium alanate without solvent. XRD patterns of synthesized materials showed that metathesis reaction of cations between metal chloride and sodium alanate was progressed favorably without any solvent. Magnesium alanate showed that 3.2 wt.% of hydrogen was evolved by the thermal decomposition. The addition of a small amount of Ti to the magnesium alanate greatly reduced hydrogen evolution temperature. Also, Ti doped magnesium alanate had a good regeneration property. Both the calcium and lithium-magnesium alanate showed the lower starting temperature of the two step hydrogen evolution and fast kinetics for the hydrogen evolution.

Evaluation of Hydrogen Embrittlement Behavior in INCONEL Alloy 617 by Small Punch Test (소형펀치 시험법을 이용한 INCONEL Alloy 617의 수소취화거동 평가)

  • Seo, Hyon-Uk;Ma, Young-Hwa;Yoon, Kee-Bong
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.21 no.4
    • /
    • pp.340-345
    • /
    • 2010
  • For the conversion into hydrogen society, not only studying facilities of hydrogen production, storage, transportation and charging system but also developing technique of ensuring safety are essentially needed. Hence, for the first step of that, evaluated the hydrogen embrittlement of Inconel alloy 617, Ni-based super heat-resisting alloy, by small punch test. Prepared the various specimens through changing electrochemical charging time and measured the toughness degradation of the specimens by small-punch test. The analysis of hydrogen embrittlement behavior were carried out by investigating the fractured surface of specimens. This study has significance on revealing mechanism of hydrogen embrittlement behavior and the factor affecting hydrogen embrittlement in the future study.