• 한국군사과학기술학회지
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• 제20권4호
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• pp.528-535
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• 2017

Fuel cells have been spotlighted in the world for being highly efficient and environmentally friendly. A hydrogen which is the fuel of fuel cell can be obtained from a number of sources. Hydrogen source for operating the polymer electrolyte membrane fuel cell(PEMFC) in the current underwater environment, such as a submarine and unmanned underwater vehicles are currently from the metal hydride cylinder. However, metal hydride has many limitations for using hydrogen carrier, such as large volume, long charging time, limited storage capacity. To solve these problems, we suggest diesel reformer for hydrogen supply source. Diesel fuel has many advantages, such as high hydrogen storage density, easy to transport and also well-infra structure. However, conventional diesel reforming system for PEMFC requires a large volume and complex CO removal system for lowering the CO level to less than 10 ppm. In addition, because the preferential oxidation(PROX) reaction is the strong exothermic reaction, cooling load is required. By changing this PROX reactor to hydrogen separation membrane, the problem from PROX reactor can be solved. This is because hydrogen separation membranes are small and permeable to pure hydrogen. In this study, we conducted the pressurized diesel reforming and water-gas shift reaction experiment for the hydrogen separation membrane application. Then, the hydrogen permeation experiments were performed using a Pd alloy membrane for the reformate gas.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2589-2593
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• 2008

In a fuel cell vehicle using polymer electrolyte membrane fuel cell(PEMFC), hydrogen is over-supplied to gain higher stack efficiency. So it is needed considering fuel efficiency to re-circulate hydrogen which is not reacted in stack. And to re-circulate hydrogen, a blower or an ejector is used. Ejector re-circulation system has several merits compared with blower system, for example no parasite energy, simple structure and no lubrication system. But the secondary flow of an ejector in fuel cell vehicle, has high humidity because of crossover problem in stack. Therefore in this paper, ejector is designed by 1-D modeling and CFD with the primary and secondary flow of hydrogen. And the ejector which has the primary and secondary flow of air, is designed to have the same Reynolds number and Mach number at the nozzle exit as the hydrogen ejector's. And this air ejector is tested while the humidity of the secondary flow is varied.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2010년도 춘계학술 발표회
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• pp.160-160
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• 2010

• 한국수소및신에너지학회논문집
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• 제18권4호
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• pp.432-438
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• 2007

The reforming process for hydrogen production generates some impurities. Impurities in hydrogen such as $CO_2$, CO, $H_2S$, $NH_3$ affect fuel cell performance. It is well known that CO generated by the reforming process may negatively affect performance of cell, cause damage on catalysts resulting performance degradation. Hydrogen produced by reforming process includes about 2% methane. The presence of methane up to 10% is reported negligible degradation in cell performance. However, methane more than 10% in hydrogen stream had not been researched. The concentration of impurity supplied to the fuel cell was verified by gas chromatography(GC). In this study, the influence of $CH_4$ on performance of PEM fuel cell was investigated by means of current vs. potential experiment, long run(10 hr) test and electrochemical impedance measurement when the concentrations of impurities were 10%, 20% and 30%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1078_1079
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• 2009

본 논문에서는 태양열 온수급탕에 관한 모티너링 연구를 해석하고 이론을 바탕으로 실 시스템을 적용 운용시 시스템의 운전특성을 비교 분석하였다. 장기 적인 일사량 측정 데이터 수집을 통하여 그래프화, 모티터링 시스템에 관한 연구를 살펴보았다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2010년도 춘계학술 발표회
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• pp.91-91
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• 2010

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1763-1770
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• 2013

A series of the block copolymers were successfully synthesized from post-sulfonated hydrophilic and hydrophobic macromers via three-step copolymerization. The degrees of sulfonation (DS) of the copolymers (10%, 30%, or 50%) were controlled by changing the molar ratio of the hydrophilic and hydrophobic parts. The resulting block copolymers were characterized by $^1H$ NMR and other technologies. The membranes were successfully cast using dimethyl sulfoxide (DMSO) solution at $100^{\circ}C$. The copolymers were characterized to confirm chemical structure by $^1H$ NMR and FT-IR. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated that all sulfonated block copolymers exhibited good thermal stability with an initial weight loss at temperatures above $240^{\circ}C$. The membranes showed acceptable ion exchange capacity (IEC) and water uptake values in accordance with DS. The maximum proton conductivity was 184 mS $cm^{-1}$ in block copolymer-50 at $60^{\circ}C$ and 100% relative humidity, while the conductivity of Nifion-115 was 160 mS $cm^{-1}$ under the same measurement conditions. AFM images of the block copolymer membranes showed well separated the hydrophilic and hydrophobic domains. From the observed results it is that the prepared block membranes can be considered as suitable polymer electrolyte membranes for the application of polymer electrolyte membrane fuel cells (PEMFC).

• 한국수소및신에너지학회논문집
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• 제27권4호
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• pp.357-364
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• 2016

Recently, the world faces the environmental problem such as air pollution due to harmful gas discharged from car and abnormal climate due to the green-house gases increased by the discharge of $CO_2$. Compressed Natural Gas (CNG), one of alternative for this problem, is less harmful, compared to the existing fossil fuel, as gaseous fuel, and less carbon in fuel ingredients and carbon dioxide generation rate relatively favorable more than the existing fuel. However, CNG fuel has the weakness of slow flame propagation speed and difficult fast burn. On the other hand, hydrogen does not include carbon in fuel ingredients, and does not discharge harmful gas such as CO and HC. Moreover, it has strength of quick burning velocity and ignition is possible with small ignition energy source and it's has wide Lean Flammability Limit. If using this hydrogen with CNG fuel, the characteristics of output and discharge gas is improved by the mixer's burning velocity improved, and, at the same time, is possible to have stable lean combustion with the reduction of $CO_2$ expected. Therefore, this research tries to identify the characteristics of engine and emission gas when mixing CNG fuel and hydrogen in each portion and burning them in spark igniting engine, and grasp the combustion stability and emission gas characteristics according and use it as the basic data of hydrogen-CNG premixed engine.

• 한국수소및신에너지학회논문집
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• 제26권4호
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• pp.363-368
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• 2015

Finding an alternative fuel and reducing environmental pollution are the main goals for future internal combustion engines. The purpose of this study is to obtain low-emission and high-efficiency by hydrogen enriched LPG fuel in a LPG engine. An experimental study was carried out to obtain fundamental data for the emit HC emission characteristics at cold start of pre-mixed LPG and hydrogen in a LPG engine with various fractions of hydrogen-LPG blends. To maintain equal volume ratio of fuel blend, the amount of HC was decreased as hydrogen was gradually added. The results showed that as hydrogen increases, in-cylinder pressure increased. Also emission of unburned hydrocarbon (HC) is sharply decreased.

• 자동차안전학회지
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• 제13권4호
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• pp.92-98
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• 2021

Recently hydrogen fuel cell buses have been deployed for the public transportations. In order to introduce buses fueled by hydrogen successfully, the research results of hydrogen bus safety should be discussed and investigated significantly. Especially, Korean government drives research in terms of various applications of hydrogen energy to replace the conventional fuel energy resources and to improve the safety evaluation. Thus it is necessary to examine vehicle crashworthiness under side impact loadings. This study was focused on the simulation result evaluation of full bus model and simplified bus model with hydrogen fuel tank module and mounting system located below floor structure due to the significance of bus side impact accidents. The finite element models of hydrogen bus, fuel tank system and side impact moving barrier were set up and simulation results reported model performance and result comparison of two side impact models. Computational results and research discussion showed the conceptual side impact framework to evaluate hydrogen bus crashworthiness.