• Korean Chemical Engineering Research
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• 제43권3호
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• pp.344-351
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• 2005

수소에너지는 기존의 석유화학공업의 원료로서 뿐만 아니라 연료전지와 연계하여 소요량이 급속히 증가할 것으로 예측된다. 장기적으로는 재생에너지를 사용한 물 전기분해, 원자력을 이용한 수소 제조가 주목받고 있지만, 안정된 기술이 확보되기까지는 화석연료를 사용한 수소 제조법이 대용량 수소 제조법 중 가장 경제적인 것으로 분석되고 있다. 현재 화석 연료 중 천연가스를 이용한 수증기 개질 수소 제조법이 상업적인 공정으로 채택되고 있으나 $CO_2$ 분리 처리 비용이 경제성 평가에 중요한 항목으로 부각되고 있다. 따라서 천연가스를 이용한 수소 제조에도 다양한 공정이 제안되고 있으므로 천연가스를 원료로 한 수소 제조 기술의 개발 현황을 살펴보았다.

• 대한금속재료학회지
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• 제46권10호
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• pp.662-671
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• 2008

The behavior of hydrogen in the steel making process was investigated. The relation between the composition of ladle slag and hydrogen concentration in molten steel was considered. The hydrogen distribution ratio between ladle slag and molten steel was increased with increasing basicity of the slag; it was about 20 when the basicity of slag was 15. Hydroxyl capacity measured from the hydrogen distribution ratio between slag and the molten steel was comparatively corresponding to the value of hydroxyl capacity measured by the equilibrium reaction of slag and $H_2O$ gas. However, it is considerably different from the value calculated by regular solution model. The influence of hydrogen on a sticking type breakout is considered. The effect of hydrogen and $H_2O$ gas on the crystallization behavior of mold powder was investigated by DHTT (Dual hot thermocouple technique). As a result, it was proved that mold powder could be crystallized by $H_2O$ gas in the atmosphere. Therefore, it is concluded that $H_2O$ gas in the atmosphere can be a possible cause of the sticking type breakout that occasionally occurs in the continuous casting process.

• 한국수소및신에너지학회논문집
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• 제34권1호
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• pp.38-46
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• 2023

Carbon neutrality policies have been strengthened to reduce emissions, and the importance of technology road maps has been emphasized. In the global industrial boiler market, carbon neutrality is implemented through fuel diversification of methane-hydrogen mixture gas. However, various problems such as flashback and flame unstability arise. There is a limit to implementing the actual system as it remains in the early stage. Therefore, it is necessary to secure the source technology of methane-hydrogen hybrid combustion system applicable to industrial fields. In this study, control program for methane-hydrogen fuel conversion was developed to expect various parameters. After determining the hydrogen mixing ratio and the input air flow, the fuel conversion control algorithm was constructed to get the parameters that achieve the target oxygen concentration in the exhaust gas. LabVIEW program was used to derive correlations among hydrogen mixing rate, oxygen concentration in exhaust gas, input amount of air and heating value.

• 한국가스학회지
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• 제23권2호
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• pp.1-8
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• 2019

근래 환경 문제가 이슈화됨에 따라, 수소 에너지에 대한 관심 역시 빠르게 집중되고 있다. 특히 국내에서는 수소 에너지의 보급을 위하여 정부 주도 하, 수소전기차 및 수소충전소의 확산이 탄력을 받고 있다. 그러나 수소 에너지의 도입 취지에 부합하는, 실질적인 국내 환경성에 대한 기여도가 평가되어야 하지만, 기존 $CO_2$ 배출량 분석 방법의 대부분은 미국의 에너지 환경을 대표하여 개발되었으므로, 국내 현실에 그대로 적응하기에는 한계가 존재한다. 따라서 본 논문에서는 국내에서 수소 생산 시 배출되는 $CO_2$ 배출량을 평가하는 방식으로, 물질 수지 기반의 수치 계산 분석을 제안한다. 제안한 방법을 바탕으로 천연가스, LPG, 나프타를 원료로 개질 반응 및 전기분해, COG를 활용한 수소 생산 시 국내에서 발생하는 $CO_2$ 배출량을 분석하였다. 또한, 해당 결과를 GREET 프로그램 분석 결과를 비교하여 제안한 방법의 신뢰성을 확인해보았다.

• Corrosion Science and Technology
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• 제8권4호
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• pp.133-138
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• 2009

For the corrosion protection of the natural gas transmission pipelines, two methods are used, cathodic protection and coating technique. In the case of cathodic protection, defects are embrittled by occurring hydrogen at the crack tip or material surface. It is however very important to evaluate whether cracks in the embrittled area can grow or not, especially in weld metal. In this work, on the basis of elastic plastic fracture mechanics, we performed the CTOD testing with various test conditions, such as testing rate and potential. The CTOD of the base metal and the weld metal showed a strong dependence of the test conditions. The CTOD decreased with decreasing testing rate and with increasing cathodic potential. The morphology of the fracture surface showed the quasi-cleavage at low testing rate and cathodic overprotection. The low CTOD was caused by hydrogen embrittlement at crack tip.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권1호
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• pp.21-32
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• 2013

Marine transportation industry is undergoing a number of problems. Some of these problems are associated with conventional marine fuel-oils. Many researchers have showed that fuel-oil is considered as the main component that causes both environmental and economic problems, especially with the continuous rising of fuel cost. This paper investigates the capability of using natural gas and hydrogen as alternative fuel instead of diesel oil for marine gas turbine, the effect of the alternative fuel on gas turbine thermodynamic performance and the employed mathematical model. The results showed that since the natural gas is categorized as hydrocarbon fuel, the thermodynamic performance of the gas turbine cycle using the natural gas was found to be close to the diesel case performance. The gas turbine thermal efficiency was found to be 1% less in the case of hydrogen compared to the original case of diesel.

• 전기학회논문지P
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• 제58권4호
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• pp.639-643
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• 2009

A reformer, which produces hydrogen from natural gas, plays a major role for producing quality hydrogen to fuel-cell system. In this paper, fuel processor is designed to deliver hydrogen(75%) from the reformer to 200W fuel-cell system, and the electrical output power of the fuel-cells is examined by being injected different hydrogen concentrations to the system. We verified that the output power characteristics of the fuel-cells with 75% reformed hydrogen was lower about 7% than the case of pure hydrogen supplied. The type of reformer in this experiment takes SMR(Steam methane reforming) process, and the temperature variation characteristics of reforming process by reactions are examined in operation.

• 한국가스학회지
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• 제16권1호
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• pp.8-14
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• 2012

수소는 온실가스 배출을 저감하기 위한 미래 에너지로 고려되고 있지만, 폭발위험에 대한 문제점을 지니고 있다. 따라서 수소가 미래 에너지로 사용되기 위해서는 폭발위험에 대한 연구가 충분히 이루어져야 한다. 폭발위험은 폭발충격에 대한 이해 즉, 폭발과정에서 압력 상승속도에 대한 분석과 밀접한 관계가 있다. 본 연구에서는 폭발에 영향을 미치는 변수, 즉 연소 전후의 비열비, 화학평형상태에서 최대폭발압력, 그리고 연소속도, 이들 변수가 압력 상승속도에 미치는 영향을 살펴보았다. 화학평형상태에서 최대폭발압력과 연소속도는 압력 상승곡선에 큰 영향을 미치는 것을 알 수 있었고, 미연소 가스의 비열비는 초기압력 상승속도보다 최종압력 상승속도에 더욱 영향을 미치고, 연소가스의 비열비는 반대로 초기압력 상승속도에 더욱 큰 영향을 미치는 것을 알 수 있었다. 연소속도는 실험 데이터로부터 구하였으며 밀폐공간에서 수소가스 폭발에서는 폭연에서 폭굉으로 전이가 일어나기에는 연소속도가 매우 느림을 알 수 있었다.

• 한국수소및신에너지학회논문집
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• 제24권1호
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• pp.12-19
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• 2013

A gasification process with pre-combustion $CO_2$ capture process, which converts coal into environment-friendly synthetic gas, might be promising option for sustainable energy conversion. In the coal gasification for power generation, coal is converted into $H_2$, CO and $CO_2$. To reduce the cost of $CO_2$ capture and to maximize hydrogen production, the removal of CO and the additional production of hydrogen might be needed. In this study, a 2l/min water gas shift system for a coal gasifier has been studied. To control the concentration of major components such as $H_2$, CO, and $CO_2$, MFCs were used in experimental apparatus. The gas concentration in these experiments was equal with syngas concentration from dry coal gasifiers ($H_2$: 25-35, CO: 60-65, $CO_2$: 5-15 vol%). The operation conditions of the WGS system were $200-400^{\circ}C$, 1-10bar. Steam/Carbon ratios were between 2.0 and 5.0. The commercial catalysts were used in the high temperature shift reactor and the low temperature shift reactor. As steam/carbon ratio increased, the conversion (1-$CO_{out}/CO_{in}$) increased from 93% to 97% at the condition of CO: 65, $H_2$: 30, $CO_2$: 5%. However the conversion decreased with increasing of gas flow and temperature. The gas concentration from LTS was $H_2$: 54.7-60.0, $CO_2$: 38.8-44.9, CO: 0.3-1%.

• 한국수소및신에너지학회논문집
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• 제22권3호
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• pp.313-318
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• 2011

This study is about characteristics of generating efficiency and $NO_x$ emissions of a 30 kW gas engine generator in case of using model biogas with hydrogen addition. In this case, both generating efficiency and $NO_x$ emissions are lower than the case of using urban gas (LNG). However, generating efficiency and $NO_x$ emissions are higher than the case of using model biogas only. It means that adding hydrogen which has a high flame propagation velocity has the possibility to improve the generating efficiency, but simultaneously it is also able to increase the $NO_x$ emissions of a gas engine generator.