• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.584-589
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• 2015

For effective power generation with fuel cells in low-oxygen environments such as submarines and unmanned underwater vehicles, a hydrogen source which has a high hydrogen storage density is required. Diesel fuel is easy to storage and supply due to its liquid phase and it has a high density per unit volume and unit mass of hydrogen that required for driving the fuel cells. In this paper, diesel fuel was selected as a hydrogen source for driving the fuel cell in oxygen lean environments. In addition, the aqueous hydrogen peroxide solution was suggested as an alternative oxidant for hydrogen production through the diesel reforming reaction because of its high oxygen density and liquid phase which makes it easy to storage. In order to determine the characteristics of hydrogen peroxide as an oxidant of diesel reforming, comparative experiments were conducted and it was found that hydrogen peroxide solution has the same characteristics when reformed with oxidants of both steam and oxygen. Moreover, the commercial diesel reforming performances were analyzed according to the reaction temperature and concentration of aqueous hydrogen peroxide solution. Then, through the 49 hours accelerated degradation tests, the possibility of hydrogen production via diesel and aqueous hydrogen peroxide solution was confirmed.

• Journal of Hydrogen and New Energy
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• v.34 no.6
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• pp.623-630
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• 2023

Recently, a hydrogen charging station-related memorandum of understanding (MOU) was signed between Korea Transport Institute and United Arab Emirates (UAE) Ministry of Transport in Abu Dhabi, creating a foundation for exporting green hydrogen charging stations and hydrogen powered public transit buses developed with Korean technology to Abu Dhabi. Reliable construction and operation of the charging stations require a thorough review on associated standards and legal requirements. In particular, it is essential to analyze currently effective standards related to hydrogen production, hydrogen vehicle charging, and hydrogen charging stations. This paper specifically focuses on comparative analysis of hydrogen-related standards in the UAE and the Republic of Korea. Similar to UAE, Korean hydrogen charging station-related standards follow International Organization for Standardization (ISO) standards. From real-life experiences in developing and operating charging stations, even more essence of ISO standards have been adopted in Korean standards than UAE. In particular, ISO standards related to fire prevention are additionally included in Korea. This paper also suggests procedural and administrative strategies for enabling application of Korean hydrogen charging station-related standards in UAE.

• Journal of Hydrogen and New Energy
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• v.31 no.5
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• pp.436-443
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• 2020

The performance prediction model of a solid oxide fuel cell stack has been developed using deep neural network technique, one of the machine learning methods. The machine learning has been received much interest in various fields, including energy system mo- deling. Using machine learning technique can save time and cost requried in developing an energy system model being compared to the conventional method, that is a combination of a mathematical modeling and an experimental validation. Results reveal that the mean average percent error, root mean square error, and coefficient of determination (R2) range 1.7515, 0.1342, 0.8597, repectively, in maximum. To improve the predictability of the model, the pre-processing is effective and interpolative machine learning and application is more accurate than the extrapolative cases.

• Journal of Hydrogen and New Energy
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• v.21 no.5
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• pp.435-441
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• 2010

To verify the possibility of a power generation system using biogas from the waste of pig farm for rural electric production, a SI gasoline engine is modified to use biogas fuel and was installed in a 20 KVA power generation system. An electronic speed regulation unit is developed to keep the system speed at 1500 rpm. Experimental investigations have been carried out to examine the performance characteristics of power generation system (such as: system frequency, phase output voltage,$\ldots$). In addition, the operating parameters and output emissions ($NO_x$, HC, and $CO_2$) of biogas-fueled engine are preliminary evaluated and analyzed for the change of system load. Results indicated that the researched power generation system shows a high stability of output voltage and frequency with help of speed regulator. Biogas fuel (mainly $CH_4$ and $CO_2$) has an environmental impact and potential as a green alternative fuel for SI engine and they would not require significant modification of existing engine hardware. Output emissions of biogas-fueled engine are found to be relative low. $NO_x$ emission increases with the increase of output electric power of the power generation system.

• Journal of Hydrogen and New Energy
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• v.25 no.5
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• pp.475-481
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• 2014

Ammonia borane ($NH_3BH_3$), as a source material for energy generation and hydrogen storage, has attracted growing interest due to its high hydrogen content. We have investigated the synthesis of ammonia borane from sodium borohydride ($NaBH_4$) and ammonium chloride ($NH_4Cl$) utilizing a low-temperature process. From our results, we obtained a maximum synthetic yield of 98.2% of ammonia borane complex. The diammoniate diborane (DADB) was detected in about 5~10mol% with in the solid ammonia borane by solid-state $^{11}B$-NMR analysis. The synthesized solid ammonia borane products were studied to characterize hydrogen release upon thermal dehydrogenation.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.51.3-51.3
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• 2010

Due to the recent public awareness of global warming and sustainable economic growth, there has been a growing interest in alternative clean energy sources. Hydrogen is considered as a clean fuel for the next generation. One of the technical challenges related to the use of hydrogen is safe monitoring of the hydrogen leak during separation, purification and transportation. For detecting various gases, chemiresistor-type gas sensors have been widely studied and used due to their well-established detection scheme and low cost. However, it is known that many of them have the limited sensitivity and slow response time, when used at low temperature conditions. In our work, a sensor based on Schottky barriers at the electrode/sensing material interface showed promising results that can be utilized for developing fast and highly sensitive gas sensors. Our hydrogen sensor was designed and fabricated based on indium oxide (In2O3)-doped tin oxide (SnO2) semiconductor nanoparticles with platinum (Pt) nanoclusters in combination with interdigitated electrodes. The sensor showed the sensitivity as high as $10^7%$ (Rair/Rgas) and the detection limit as low as 30 ppm. The sensor characteristics could be obtained via optimized materials synthesis route and sensor electrode design. Not only the contribution of electrical resistance from the film itself but also the interfacial effect was identified as an important factor that contribute significantly to the overall sensor characteristics. This promises the applicability of the developed sensor for monitoring hydrogen leak at room temperature.

• Journal of Hydrogen and New Energy
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• v.21 no.1
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• pp.42-49
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• 2010

Increasing environmental concerns regarding the use of fossil fuels and global wanning have prompted researcher to investigate alternative fuels. The purpose of this study is to investigate the syngas production by biogas reforming using a compression spark ignition engine. The parametric screening studies were carried out according to the variations of oxygen enrichment rate, biogas $CO_2$ ratio, intake gas temperature, and engine revolution. When the oxygen enrichment rate and input gas temperature increased, hydrogen and carbon monoxide were increased. But the biogas $CO_2$ ratio and engine revolution increased, the syngas were reduced. For the reforming of methane 100% only, generation of hydrogen and carbon monoxide was 58% and 17%, respectively. However when the biogas $CO_2$ ratio was 40%, hydrogen and carbon monoxide concentration were about 20% each.

• Nuclear Engineering and Technology
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• v.41 no.4
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• pp.413-426
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• 2009

Nuclear energy plays an important role in world energy production by supplying 6% of the world's current total electricity production. However, 86% of the energy consumed worldwide to produce industrial process heat, to generate electricity and to power the transportation sector still originates in fossil fuels. To cope with dwindling fossil fuels and climate change, it is clear that a clean alternative energy that can replace fossil fuels in these sectors is urgently required. Clean hydrogen energy is one such alternative. Clean hydrogen can play an important role not only in synthetic fuel production but also through powering fuel cells in the anticipated hydrogen economy. With the introduction of the high temperature gas-cooled reactor (HTGR) that can produce nuclear heat up to $950^{\circ}C$ without greenhouse gas emissions, nuclear power is poised to broaden its mission beyond electricity generation to the provision of nuclear process heat and the massive production of hydrogen. In this paper, the features and potential of the HTGR as the energy source of the future are addressed. Perspectives on nuclear heat and hydrogen applications using the HTGR are discussed.

• Journal of Hydrogen and New Energy
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• v.29 no.3
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• pp.235-242
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• 2018

Hydrogen can be produced by reforming reaction of natural gas (NG) and biogas, or by water electrolysis. In this study, hydrogen production through water-electrolysis needs superheated steam above $700^{\circ}C$ for high efficiency. The production method of hydrogen like this was recommended for the 4-type processes for superheated steam ($700^{\circ}C$, 3 atm) by Bio-SRF combustion furnace. The 4-type processes to produce superheated steam at $700^{\circ}C$ from the heat source of SRF combustion furnace was simulated using PRO II. The optimum process was selected through exergy analysis. The difference of process 1 and 2 is to the order of depressure and heating process to change $180^{\circ}C$ and 7 atm to $700^{\circ}C$ and 3 atm. Process 3 and 4 is to utilize 25% of steam to generate superheated steam and remaining to use for the power generation by steam generator.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.596-605
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• 2019

Proton-conducting perovskite ceramic materials are highly promising for solid electrolytes as well as catalysts at high temperatures. Therefore, they possess an outstanding potential for the membrane reactor in which both reaction and separation occur at a same time. Especially, in the case of hydrogen production catalyst, hydrogen separation, and the membrane reactor coupled with catalyst and separation, extensive results have been reported on the effect of the dopant in the solid electrolytes, temperature, and composition of reactants on the performance. In this review, the recent research trend on the application of proton-conducting ceramic materials to hydrogen production catalyst, hydrogen separation, and membrane reactor is surveyed. Moreover, the potential application and prospect of these materials to the next-generation hydrogen production and separation is discussed.