• International Journal of Automotive Technology
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• 제2권2호
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• pp.39-45
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• 2001

Hydrogen is seen as one of the important energy vectors of the next century. Hydrogen as a renewable energy source, provides the potential for a sustainable development particularly in the transportation sector. Hydrogen driven vehicles reduce both local as well as global emissions. The laboratory of transporttechnology (University of Gent) converted a GM/Crusader V-8 engine for hydrogen use. Once the engine is optimised, it will be built in a low-floor midsize hydrogen city bus for public demonstration. For a complete control of the combustion process and to increase the resistance to backfire (explosion of the air-fuel mixture in the inlet manifold), a sequential timed multipoint injection of hydrogen and an electronic management system is chosen. The results as a function of the engine parameters (ignition timing. injection timing and duration, injection pressure) we given. Special focus is given to topics related to the use of hydrogen as a fuel: ignition characteristics (importance of electrode distance), quality of the lubricating oil (crankcase gases with high contents of hydrogen), oxygen sensors (very lean operating conditions), noise reduction (configuration and length of inlet pipes). The advantages and disadvantages of a power regulation only by the air to fuel ratio (as for diesel engines) against a throttle regulation (normal gasoline or gas regulation) are examined. Finally the goals of the development of the engine are reached: power output of 90 kW, torque of 300 Nm, extremely low emission levels and backfire-safe operation.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.688-696
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• 2011

수소는 에너지를 방출하는 과정에서 부산물로 물만 배출하기 때문에 지속가능한 청정에너지원 중의 하나이다. 현재 세계적으로 사용되는 수소는 대부분 화석연료의 개질에 의해 생산되고 있으며 1kg 수소를 생산하는 과정에서 7kg 이상의 이산화탄소를 배출하고 있다. 수소를 생산하는 과정에서 투입되는 에너지와 자원이 지속가능하고 재생 가능해야 수소를 청정에너지원이라 할 수 있다. 바이오매스는 화석연료를 대체할 수 있는 에너지원중의 하나인데, 그 이유는 바이오매스로부터 수소를 생산할 수 있으며 수소생산과정에서 발생하는 이산화탄소는 바이오매스 생산과정에서 소비되기 때문에 이론적으로 이산화탄소를 발생시키지 않는 에너지원이다. 태양에너지와 물로부터 수소를 생산하는 기술은 지구상에 널려있는 자연에너지와 물을 사용하기 때문에 인류가 직면한 에너지와 환경문제를 해결하기 위한 가장 이상적인 기술 중의 하나이다.

• 대한금속재료학회지
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• 제46권5호
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• pp.296-303
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• 2008

Hydrogen permeation through dense palladium-based membranes has attracted the attention of many scientists largely due to their unmatched potential as hydrogen-selective membranes for membrane reactor applications. Although it is well known that the permeation mechanism of hydrogen through Pd involves various processes such as dissociative adsorption, transitions to and from the bulk Pd, diffusion within Pd, and recombinative desorption, it is still unclear which process mainly limits hydrogen permeation at a given temperature and hydrogen partial pressure. In this study, we report an all-electron density-functional theory study of hydrogen permeation through Pd membrane (using VASP code). Especially, we focus on the variation of the energy barrier of the penetration process from the surface to the bulk with hydrogen coverage, which means the large reduction of the fracture stress in the brittle crack propagation considering Griffith's criterion. It is also found that the penetration energy barrier from the surface to the bulk largely decreases so that it almost vanishes at the coverage 1.25, which means that the penetration process cannot be the rate determining process.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.175-184
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• 2024

This study focuses on investigating the importance of managing greenhouse gas emissions from global energy consumption, specifically examining domestic targets for clean hydrogen production. Using life cycle assessment, we evaluated reductions in global warming potential and assessed the carbon neutrality contribution of the domestic hydrogen sector. Transitioning from brown or grey hydrogen to blue or green hydrogen can significantly reduce emissions, potentially lowering CO₂ equivalent levels by 2030 and 2050. These research findings underscore the effectiveness of clean hydrogen as an energy management strategy and offer valuable insights for technology development.

• 한국재료학회지
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• 제26권5호
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• pp.241-245
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• 2016

Hydrogen is considered a potential future energy source. Among other applications of hydrogen, hydrogen-rich water is emerging as a new health care product in industrial areas. Water electrolysis is typically used to generate a hydrogen rich water system. We annealed 10AA carbon paper in air to use it as an electrode of a hydrogen rich water generator. Driven by annealing, structural changes of the carbon paper were identified by secondary electron microscope analysis. Depending on the various annealing temperatures, changes of the hydrophilic characteristics were demonstrated. The crystal structures of pristine and heat-treated carbon paper were characterized by X-ray diffraction. Improvement of the efficiency of the electrochemical oxygen evolution reaction was measured via linear voltammetry. The optimized annealing temperature of 10AA carbon paper showed the possibility of using this material as an effective hydrogen rich water generator.

• 한국수소및신에너지학회논문집
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• 제7권1호
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• pp.111-115
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• 1996

Metal atom rearrangement has been shown to take place under the influence of hydrogen-induced atomic diffusion (HIAD) in initially homogeneous fee palladiumalloys by electron microprobe analysis, optical microscopy, mechanical property tests and hydrogen isotherms. HIAD takes place in palladium alloys at moderate to elevated temperatures leading to phase segregation under conditions where segregation does not normally occur, i.e., in the absence of H over the time scale of the experiments. From these results, it is confirmed that dissolved hydrogen plays a dual role in some of these alloys, i.e. it catalyzes metal atom diffusion. This research demonstrates the potential utility of employing H-induced changes for phase diagram determination of Pd alloys and possibly for other alloy system.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 춘계학술발표회 초록집
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• pp.111-114
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• 1996

Hydrogen generation by dissociation of water is described. The major force for the dissociation comes from the oxidation potential of the reactive metal reacting with water whereas the minor role is played by electrical discharge which helps sustain the reaction. A premixed reactive metal/water system undergoes a fast hydrogen generation upon the ignition by an electrical pulse. In another method the reactive metal can be fed into the discharge. Some characteristics of the methods are discussed.

• 공업화학
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• 제30권6호
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• pp.667-672
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• 2019

비재생 에너지원인 화석 연료의 환경 문제들이 발생하면서 국제 사회는 탈탄소화 사회를 지향하고 있으며 이를 위해 Power 2 Gas (P2G) 시스템의 실증화를 목표로 많은 연구들이 진행 중이다. 그 중 암모니아는 수소 캐리어의 역할, 수소 생산 공급체의 역할, 직접적인 사용 등의 많은 이점들이 있다. 본 총설에서는 암모니아의 특성과 해외 동향의 움직임을 분석하여 암모니아의 수소 에너지 공급 산업에서의 잠재력에 대해 기술하고자 한다.

• 한국수소및신에너지학회논문집
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• 제32권5호
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• pp.356-364
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• 2021

During the hydrogen fueling process, hydrogen temperature inside the compressed tank were limited below 85℃ due to the allowable pressure of tank material. The chiller system to cool compressed hydrogen used R407C, greenhouse gas with a high global warming potential (GWP), as a refrigerant. To reduce greehouse gas emission, it should be replaced by refrigerant with a low GWP. This study proposes a chiller system for fueling hydrogen with R290, consisted in propane, by applying the C3 pre-cooled system use d in the LNG liquefaction process. The proposed system consisted of hydrogen compression and cooling sections and optimized the operating pressure through exergy analysis. It was also compared to the exergy efficiency with the existing system at the optimal operating pressure. The result showed that the optimal operating pressure is 700 kPa in 2-stage, 840 kPa/490 kPa in 3-stage, and the exergy efficiency increased by 17%.

• 신재생에너지
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• 제18권2호
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• pp.50-59
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• 2022

The Korean government announced the "1st Basic Plan for the Transition to Hydrogen Economy" in 2021 and declared the establishment of a hydrogen industry ecosystem by 2040. To build a low-carbon power system, resources that can efficiently accommodate renewable energy are required, and green hydrogen is considered a potential solution. This study analyzed the economic feasibility of green hydrogen-based sector coupling to reduce curtailment of renewable generation in the Jeju power system by 2025 under the scenario of with or without HVDC#3. The result showed that HVDC#3 significantly reduced the frequency of curtailment from 16.1% to 3.0%. In addition, green hydrogen-based sector coupling was an economically feasible option as result showed an IRR of 4.86% when HVDC#3 was connected and 11.45% when it was not under the condition of achieving 50% curtailment reduction. This study shows that the higher the level of renewable energy deployment, the more delayed the HVDC connection between Jeju and the main land, and the lower the SMP, the more economically feasible the green hydrogen-based sector coupling is. Furthermore, this study suggests that the policy goal of completely reducing curtailment is not economically efficient.