• Journal of Welding and Joining
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• 제30권6호
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• pp.10-14
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• 2012

Recently the low alloy steel plate made with manganese-molybdenum is used widely in steam drum and separator of the new coal-fired power plant boiler. This material is suitable for the vapor storage of high pressure and high temperature. The high temperature creep strength of Mn-Mo alloy is higher than the carbon plate(SA516) that used in the subcritical pressure boiler. It reduces the thickness of the pressure vessel and makes the lightweight possible. Recently in the power plant boiler operation and production process, the damage has happened frequently in the heat affected zone and base material according to the hydrogen crack and delayed crack. This paper describes the research result about the damage case experienced in the boiler steam drum production process and present the optimum manufacture method for the similar damage prevention of recurrence.

• 한국수소및신에너지학회논문집
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• 제28권3호
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• pp.295-299
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• 2017

In this study, computer simulation and optimization works have been performed for an open-loop Rankine cycle to generate power using five cases of liquefied natural gas compositions. PRO/II with PROVISION V9.4 from Schneider electric company was used, and the Soave-Redlich-Kwong equation of the state model was utilized for the design of the power generation cycle. It was concluded that more power was obtained from less molecular weight liquefied natural gas since there was more volumetric flow rate with less molecular weight.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.470-477
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• 2010

The IGCC (Integrated gasification combined cycle) is known for one of the highest efficiency and the lowest emitting coal fueled power generating technologies. As the core technology of this system is the gasifier to make the efficiency and the continuous operation time increase, the research about different coal's gasification has been conducted. Our research group had set-up the coal gasifier for the pilot test to study the effect of different coals-Shenhua and Adaro coal- on gasification characteristics. Gasification conditions like temperature and pressure were controlled at a fixed condition and coal feed rate was also controlled 30 kg/h to retain the constant experimental condition. Through this study we found effects of coal composition and $O_2$/coal ratio on the cold gas efficiency, carbon conversion rate. The compounds of coal like carbon and ash make the performance of gasifier change. And carbon conversion rate was decreased with reduced $O_2$/coal ratio. The optical $O_2$/coal ratio is 0.8 for the highest cold gas efficiency approximately. At those operating conditions, the higher coal has the C/H ratio, the lower syn-gas has the $H_2$/CO ratio.

• 한국수소및신에너지학회논문집
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• 제25권4호
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• pp.425-435
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• 2014

Simulation studies on catalytic methanation reaction in externally cooled tubular reactor filled with monolithic catalysts were carried out using a general purpose modelling tool $gPROMS^{(R)}$. We investigated the effects of operating parameters such as gas space velocity, temperature and pressure of feeding gas on temperature distribution inside the reactor, overall CO conversion, and chemical composition of product gas. In general, performance of methanation reaction is favored under low temperature and high pressure for a wide range of their values. However, methane production becomes negligible at temperatures below 573K when the reactor temperature is not high enough to ignite methanation reaction. Capacity enhancement of the reactor by increasing gas space velocity and/or gas inlet pressure resulted no significant reduction in reactor performance and heat transfer property of catalyst.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.104-104
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• 2015

Due to the demand of the cold neutron flux in the neutron science and beam utilization technology, the cold neutron source (CNS) has been constructed and operating in the nuclear research reactor all over the world. The majority of the heat load removal scheme in the CNS is two-phase thermosiphon using the liquid hydrogen as a moderator. The CNS moderates thermal neutrons through a cryogenic moderator, liquid hydrogen, into cold neutrons with the generation of the nuclear heat load. The liquid hydrogen in a moderator cell is evaporated for the removal of the generated heat load from the neutron moderation and flows upward into a heat exchanger, where the hydrogen gas is liquefied by the cryogenic helium gas supplied from a helium refrigeration system. The liquefied hydrogen flows down to the moderator cell. To keep the required liquid hydrogen stable in the moderator cell, the CNS consists of an in-pool assembly (IPA) connected with the hydrogen system to handle the required hydrogen gas, the vacuum system to create the thermal insulation, and the helium refrigeration system to provide the cooling capacity. If one of systems is running out of order, the operating research reactor shall be tripped because the integrity of the CNS-IPA is not secured under the full power operation of the reactor. To prevent unscheduled reactor shutdown during a long time because the research reactor has been operating with the multi-purposes, the introduction of the standby cooling system (STS) can be a solution. In this presentation, the design considerations are considered how to design the STS satisfied with the following objectives: (a) to keep the moderator cell less than 350 K during the full power operation of the reactor under loss of the vacuum, loss of the cooling power, loss of common electrical power, or loss of instrument air cases; (b) to circulate smoothly helium gas in the STS circulation loop; (c) to re-start-up the reactor within 1 hour after its trip to avoid the Xenon build-up because more than certain concentration of Xenon makes that the reactor cannot start-up again; (d) to minimize the possibility of the hydrogen-oxygen reaction in the hydrogen boundary.

• Advances in Energy Research
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• 제5권2호
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• pp.107-128
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• 2017

Energy is a major component of almost all economic, production, and service activities, and rapid population growth, urbanization and industrialization have led to ever growing demand for energy. Limited energy resources and increasingly evident environmental effects of fossil fuel consumption has led to a growing awareness about the importance of further use of renewable energy sources in the countries energy portfolio. Renewable hydrogen production is a convenient method for storage of unstable renewable energy sources such as wind and solar energy for use in other place or time. In this study, suitability of 25 cities located in Iran's western region for renewable hydrogen production are evaluated by multi-criteria decision making techniques including TOPSIS, VIKOR, ELECTRE, SAW, Fuzzy TOPSIS, and also hybrid ranking techniques. The choice of suitable location for the centralized renewable hydrogen production is associated with various technical, economic, social, geographic, and political criteria. This paper describes the criteria affecting the hydrogen production potential in the study region. Determined criteria are weighted with Shannon entropy method, and Angstrom model and wind power model are used to estimate respectively the solar and wind energy production potential in each city and each month. Assuming the use of proton exchange membrane electrolyzer for hydrogen production, the renewable hydrogen production potential of each city is then estimated based on the obtained wind and solar energy generation potentials. The rankings obtained with MCDMs show that Kermanshah is the best option for renewable hydrogen production, and evaluation of renewable hydrogen production capacities show that Gilangharb has the highest capacity among the studied cities.

• 한국수소및신에너지학회논문집
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• 제24권4호
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• pp.295-301
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• 2013

Long-term global energy-demand growth is expected to increase driven by strong energy-demand growth from developing countries. Fusion power offers the prospect of an almost inexhaustible source of energy for future generations, even though it also presents so far insurmountable scientific and engineering challenges. One of the challenges is safe handling of hydrogen isotopes. Metal hydrides such as depleted uranium hydride or ZrCo hydride are used as a storage medium for hydrogen isotopes reversibly. The metal hydrides bind with hydrogen very strongly. In this paper, we carried out a modeling and simulation work for absorption/desorption of hydrogen by ZrCo in a horizontal annulus cylinder bed. A comprehensive mathematical description of a metal hydride hydrogen storage vessel was developed. This model was calibrated against experimental data obtained from our experimental system containing ZrCo metal hydride. The model was capable of predicting the performance of the bed for not only both the storage and delivery processes but also heat transfer operations. This model should thus be very useful for the design and development of the next generation of metal hydride hydrogen isotope storage systems.

• 한국컴퓨터그래픽스학회논문지
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• 제15권2호
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• pp.35-40
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• 2009

본 논문에선 수소 경제의 핵심 인프라 시설이며, 차세대 동력원인 수소에너지 관리 시설의 관리자들의 안전교육 및 훈련을 위한 가상체험 모들을 제안한다. 우리의 시스템은 이벤트 기반의 웹 3D기술을 사용하여, 일반적인 사용자가 손쉽게 사이트에 접속하여 실제 모델별 수소충전소를 가상으로 경험하며, 내부적으로 위치한 안전장치에 대한 가상 경험을 제공한다. 사용자는, 가상현실 환경 내에서 다양한 이벤트를 통해 안전사고시 대처상황을 습득할 수 있으며, 추가적으로 동영상과 음성 등의 멀티 미디어 객체의 제공으로 보다 나은 교육환경을 제시한다. 본 시스템을 사용하며, 실제 수소충전소의 관리자들의 교육기능을 향상시킬 수 있으며, 향후 수소충전소의 홍보수단으로도 사용이 가능하다.

• 한국수소및신에너지학회논문집
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• 제34권2호
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• pp.155-161
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• 2023

Recently, a study on alternative and renewable energy is being conducted due to energy depletion and environmental problems. In particular, a hydrogen has the advantage of converting and storing the remaining energy into water-electrolyzed hydrogen through renewable energy generation. In general, due to reasons such as insulation problems, a study on high-pressure hydrogen storage tanks and related parts has recently been conducted. However, in the case of liquid hydrogen, the volume can be reduced by about 800 times or more compared to high-pressure hydrogen gas, so the study on this is needed as a technology that can increase energy density. In this study, the evaporation characteristics were analyzed under fixed heat flux conditions for liquid hydrogen storage tanks and the change in thermal stratification according to sloshing was analyzed. The heat flux condition was fixed at 250 W/m² and the horizontal resonance frequency of the primary mode was applied to the storage tank. As a result, it was confirmed that the thermal stratification phenomenon decreased compared to the case where the slashing was not present due to forced convection when the slashing was present.

• 한국수소및신에너지학회논문집
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• 제34권3호
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• pp.256-266
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• 2023

Hydrogen production can be classified based on the energy source, primary reactor type, and whether or not it emits carbon dioxide. Utilizing color representation proves to be an effective means of expressing these distinctive characteristics. Among the various clean hydrogen production techniques, there has been a growing interest in turquoise hydrogen production, which involves the decomposition of methane or other fossil fuels. This method offers advantages in terms of large-scale production and cost reduction through the sale of solid-carbon byproduct. In this study, an extensive literature review was conducted to select and analyze several promising candidates for turquoise hydrogen production processes. The efficiency and economics of these processes were evaluated using stream data reported in the literature sources. The findings indicate that the levelized cost of hydrogen production (LCOH) is significantly influenced by the sales of byproducts, specifically the solid-carbon and carbon monoxide byproducts.