• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.5
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• pp.473-481
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• 2007

Compared to other types of fuel cells, SOFC has advantages like a wide output range and the direct use of hydrocarbon fuel without the process of external reforming. Particularly because the direct use of fuel without reforming reaction is closely linked to overall system efficiency, it is a very attractive advantage. We tried the operation with methane. However, although methane has a small number of carbons compared to other hydrocarbon fuels, our experiment found the deposition of carbon on the surface of the SOFC electrode. To overcome the problem, we tried the operation through activating internal reforming. The reason that internal reforming was possible was that SOFC runs at high temperature compared to other fuel cells and its electrode is made of Ni, which functions as a catalyst favorable for steam reforming.

• Journal of the Korean Society of Combustion
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• v.21 no.1
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• pp.8-17
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• 2016

Downstream interactions between lean premixed flames with mutually different fuels of syngas and $CH_4$ have been numerically investigated particularly on and near lean extinction limits. The interaction characteristics between lean premixed (50% $H_2$ + 50% CO)-air and $CH_4$-air flames were shown to be quite different from those between the same hydrocarbon flames. The lean extinction boundaries were of slanted shape, thereby implying strong interactions. The weaker flames had negative flame speeds on the upper extinction boundaries, whereas the weaker flame speeds on the lower extinction boundaries were both negative and positive. The results also showed that the flame interaction characteristics did not follow the general tendency with the dependency of Lewis number in downstream interactions between the same hydrocarbon flames. Importance of chemical interaction in flame characteristics is discussed in the downstream interactions between lean premixed (50% $H_2$ + 50% CO)-air and $CH_4$-air flames.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.7-12
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• 2006

The propagation rates ($U_{edge}$) of various premixed edge-flames were measured as a function of global strain rate (${ \sigma}$), mixture strength, and Lewis number (Le). Using a counterflow slot-jet burner with electrical heaters at each end, both advancing (positive $U_{edge}$) and retreating (negative $U_{edge}$) edges can be studied as they propagate along the long dimension of the burner. Preliminary results are presented for single and twin premixed hydrocarbon edge-flames in terms of the effects on $U_{edge}$. A low-${\sigma}$ extinction limit has been discovered for all mixtures tested but further analysis is necessary for full characterization since sufficiently $high-{\sigma}$ leads to an apparent stability limit. Propagation rates clearly show a strong dependence on Le. Future work will focus on completing the premixed hydrocarbon edge-flame analysis and include investigations into non-premixed edge-flames and edge-flames composed of fuels such as hydrogen ($H_2$) with significantly lower Le.

• Journal of Surface Science and Engineering
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• v.42 no.3
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• Asian Journal of Atmospheric Environment
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• v.1 no.1
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• pp.19-27
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• 2007

Hazardous polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) are mainly originated from imperfect combustion of fossil fuels such as petroleum and coal. The consumptions of not only petroleum but also coal have been increasing in the East Asian countries. This review describes the result of international collaboration research concerning characteristics and major contributors of atmospheric PAHs and NPAHs in cities in Japan, Korea, China and Russia. We collected airborne particulates in ten cities in the above countries and six PAHs and eleven NPAHs were determined by HPLC methods using fluorescence and chemiluminescence detections. The total PAH concentrations were much higher in Chinese cities (Fushun, Tieling, Shenyang and Beijing) than those in other cities (Vladivostok, Busan, Kanazawa, Kitakyushu, Sapporo and Tokyo). The total NPAH concentrations were also higher in Chinese cities than those in the other cities. The [NPAH]/[corresponding PAH] ratios are much larger in diesel-engine exhaust particulates than those in coal-burning particulates. The [1-nitropyrene]/[pyrene] ratio of airborne particulates was much smaller in the four Chinese cities, suggesting that coal combustion systems such as coal heaters were the main contributors. On the other hand, the ratios were larger in Korean and Japanese cities, suggesting the large contribution of diesel-engine vehicles.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.140-145
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• 2014

Exploitation of renewable energies is on the increase to mitigate the reliance on fossil fuels and other natural gases with rocketing prices currently due to the depletion of their reserves not to mention their diverse consequences on the environment. Divergently, there are lots of industries "throwing" heat at higher temperatures as by products into the environment. This waste heat can be recovered through organic Rankine systems and converted to electrical energy with a waste heat recovery organic Rankine cycle system (WHR-ORC). This study uses the annual average condenser effluent from Namhae power plant as heat source and surface seawater as cooling source to analyze a waste heat recovery organic Rankine cycle using the Aspen HYSYS simulation software package. Hydrocarbon mixtures are employed as working fluid and varied in a ratio of 9:1. Results indicate that Pentane/Isobutane (90/10) mixture is the favorable working fluid for optimizing the waste heat recovery organic Rankine cycle at the set simulation conditions.

• Journal of Energy Engineering
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• v.16 no.2
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• pp.58-63
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• 2007

In recent years, the technologies for the production of synthetic fuel from natural gas have been attracting considerable interest because of high oil prices. While oil prices remaining high, GTL (Gas-to-Liquids) technology would provide an attractive option for utilizing gas resources. Furthermore, GTL fuels contain almost zero sulfur and low aromatics and have a very high cetane so that they are estimated to be environmentally friendly diesel fuels able of meeting the advanced fuel specifications of the 21st century. GTL process generally consists of three primary steps: synthesis gas production from natural gas reforming, hydrocarbon production from synthesis gas by Fischer-Tropsch (F-T) synthesis, product upgrading by hydrocracking/hydroisomerization. This paper presents a brief summary of GTL technology and worldwide development trend about it focusing on the reforming of natural gas and the F-T synthesis.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.333-341
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• 2017

Recently, the earth has shown the limit of environmental capacity. It is also experiencing an environmental crisis with rising energy prices and depletion of coal. Therefore, development of renewable energy is very important solution. However, waste fuel solid are renewable fuels, but they cause environmental problems. In this study, the emission characteristics of hazardous air pollutants were analyzed through measurements at the facilities using solid fuels (SRF, BIO-SRF). Analysis method of PAHs are based on the Korea Standard Methods for Examination. The analysis of PAHs showed that the concentration much higher in Naphthalene, and Benzo(a)pyrene showed at a higher concentration incertain sources. As a result of gas phase and particle phase PAHs, most of Benzo(a)pyrene appeared to be particulate. Through the results of this study will provide basic data for atmospheric environmental management.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.823-833
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• 2010

For the study of thermophysical properties of kerosene for the liquid rocket and aviation fuels, the surrogate models are investigated. The density distributions based on the real gas equations of state(Soave modification of Redlich-Kwong and Peng-Robinson equation of state) and NIST SUPERTRAPP(extended corresponding state principle) are compared with the previous experimental results at supercritical conditions. The error range of thermophysical properties analyzed for the surrogate models as well. Peng-Robinson equation of state and extended corresponding state principle are especially accurate for the hydrocarbon fuels but the appropriate surrogate models need to be chosen to the operation conditions such as pressure and temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.991-994
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• 2017

In hypersonic aircraft, increase of aerodynamic and engine heat lead thermal load in airframe. It could lead structural change of aircraft's component and malfunctioning. Endothermic fuels are liquid hydrocarbon fuels which are able to absorb the heat load by undergoing endothermic reactions. In this study, we investigated the method of measuring the heat sink of catalyst by using exo-tetrahydrodicyclopentadiene as a fuel in a packed bed flow reactor similar to the actual reaction conditions.