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Methane Conversion Using Dielectric Barrier Discharge: Comparison with Thermal Process and Catalyst Effects

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Journal of Natural Gas Chemistry 2006年第2期15卷 87-92页

作者： Antonius Indarto Jae-Wook Choi Hwaung Lee hyung keun song Korea Institute of Science and Technology Clean Technology Research CenterP.O. Box 131CheongryangSeoul 130-650Korea

The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effects on the conversion and reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of methane has been 80% at an input flow rate of 5 ml/min and a discharge voltage of 4 kV. Experimental results also show that the optimum condition has occurred at a high discharge voltage and higher input flow rate. In terms of product distribution, a higher flow rate or shorter residence time can increase the selectivity for higher hydrocarbons. No hydrocarbon product was detected using the thermal method, except hydrogen and carbon. Increasing selectivity for ethane was found when Pt and Ru catalysts presented in the plasma reaction. Hydrogenation of acetylene in the catalyst surface could have been the reason for this phenomenon as the selectivity for acetylene in the products was decreasing.

关键词： plasma dielectric barrier discharge thermal process methane conversion catalyst

Partial Oxidation of Methane with Sol-Gel Fe/Hf/YSZ Catalyst in Dielectric Barrier Discharge: Catalyst Activation by Plasma

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Journal of Rare Earths 2006年第5期24卷 513-518页

作者： Antonius Indarto Jae-Wook Choi Hwaung Lee hyung keun song Jelliarko Palgunadi Clean Technology Research Center Korea Institute of Science and Technology KoreaDepartment of Chemical and Biological Engineering Korea University Korea Clean Technology Research Center Korea Institute of Science and Technology Korea Hydrogen Energy Research Center Korea Institute of Science and Technology Korea

A 1% Fe-30% Hf over yttria-stabilized zirconia catalyst in combination with novel plasma-assisted activation techniques for a direct partial oxidation of methane to methanol was tested using dielectric barrier discharge plasma at ambient temperature and atmospheric pressure. However, instead of methanol, the reaction products were dominated by HE, CO, CO2, C2, and H2O. A catalytically activated plasma process increased the production of methanol compared with a noncatalytic plasma process. The maximum selectivity of methanol production was achieved using a catalyst that was treated at higher applied power.

关键词： methane oxidation dielectric barrier discharge catalyst plasma activation rare earths

Kinetic Modeling of Plasma Methane Conversion Using Gliding Arc

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Journal of Natural Gas Chemistry 2005年第1期14卷 13-21页

作者： Antonius Indarto Jae-Wook Choi Hwaung Lee hyung keun song

Plasma methane (CH_4) conversion in gliding arc discharge was examined. Theresult data of experiments regarding the performance of gliding arc discharge were presented in thispaper. A simulation which is consisted some chemical kinetic mechanisms has been provided toanalyze and describe the plasma process. The effect of total gas flow rate and input frequencyrefers to power consumption have been studied to evaluate the performance of gliding arc plasmasystem and the reaction mechanism of decomposition. Experiment results indicated that the maximumconversion of CH_4 reached 50% at the total gas flow rate of 1 L/min. The plasma reaction wasoccurred at the atmospheric pressure and the main products were C (solid), hydrogen, and acetylene(C_2H_2). The plasma reaction of methane conversion was exothermic reaction which increased theproduct stream temperature around 30-50℃.

关键词： plasma gliding arc methane conversion reaction mechanism

Decomposition of CCl_4 and CHCl_3 on gliding arc plasma

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Journal of Environmental Sciences 2006年第1期18卷 83-89页

作者： Antonius Indarto CHOI Jae-wook LEE Hwaung song hyung-keun Korea Institute of Science and Technology Clean Technology Research Center P.O. Box 131 Cheongryang Seoul 130-650 Korea Korea Institute of Science and Technology Clean Technology Research Center P.O. Box 131 Cheongryang Seoul 130-650 Korea.

Decomposition of chlorinated hydrocarbons, CCl4 and CHCl3, in gliding plasma was examined. The effects of initial concentrations, total gas flow rates, and power consumption have been investigated. The conversion result was relatively high. It reached 80% for CCl4 and 97% for CHCl3. Using atmospheric air as the carrier gas, the plasma reaction occurred at exothermic reaction and the main products were CO2, CO, and Cl2. Transformation into CCl4 was also detected for CHCl3 decomposition reaction. The conversion of CCh and CHCl3 were increased with the increasing applied frequency and decreasing total gas flow rate.

关键词： plasma gliding arc CCl4 CHCl3 decomposition reaction

The kinetic studies of direct methane oxidation to methanol in the plasma process

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Chinese Science Bulletin 2008年第18期53卷 2783-2792页

作者： INDARTO Antonius CHOI Jae-Wook LEE Hwaung song hyung keun Department of Chemical and Biochemical Engineering Korea UniversitySeoul 136-701KoreaClean Technology Research Center Korea Institute of Science and Technology Seoul 130-650 Korea Clean Technology Research Center Korea Institute of Science and TechnologySeoul 130-650 Korea Clean Technology Research Center Korea Institute of Science and TechnologySeoul 130-650Korea

The research outlined here includes a study of methanol production from direct methane conversion by means of thermal and plasma method. The kinetic study, derived from thermal-based approach, was carried out to investigate thoroughly the possible intermediate species likely to be presented in the process. A set of plasma experiments was undertaken by using dielectric barrier discharge (DBD), classified as non-thermal plasma, done at atmospheric pressure and room temperature. Plasma proc- ess yields more methanol than thermal process at the same methane conversion rates and methane to oxygen feed ratios. Oxidation reaction of thermal process resulted CO and CO2 as the most dominant products and the selectivity reached 19% and 68%, respectively. Moreover, more CO and less CO2 were produced in plasma process than in thermal process. The selectivity of CO and CO2 by plasma was 47% and 20%, respectively. Ethane (C2H6) was detected as the only higher hydrocarbon with a signifi- cant concentration. The concentration of ethane reached 9% of the total products in plasma process and 17% in thermal process. The maximum selectivity of methanol, the target material of this research, was 12% obtained by plasma method and less than 5% by thermal process. In some certain points, the kinetic model closely matched with the experimental results.

关键词：等离子体热采方法部分氧化甲烷甲醇

Mass transfer in the absorption of SO_2 and NO_x using aqueous euchlorine scrubbing solution

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Journal of Environmental Sciences 2009年第2期21卷 155-161页

作者： DESHWAL Bal-Raj LEE hyung-keun Department of Chemistry A.I.J.H.M. College Green-house Gas Research Center Korea Institute of Energy Research

Attempts have been made to generate euchlorine gas by chlorate-chloride process and to utilize it further to clean up SO2 and NOx from the flue gas in a lab scale bubbling reactor. Preliminary experiments were carded out to determine the gas and liquid phase mass transfer coefficients and their correlation equations have been established. Simultaneous removal of SO2 and NOx from the simulated flue gas using aqueous euchlorine scrubbing solution has been investigated. Euchlorine oxidized NO into NO2 completely and the later subsequently absorbed into the scrubbing solution in the form of nitrate. SO2 removal efficiency around 100% and NOx removal efficiency around 72% were achieved under optimal conditions. Mass balance has been confirmed by analyzing the sulfate, nitrate, euchlorine and chloride ion using ion chromatograph/auto-titrator and comparing it with their corresponding calculated values.

关键词： mass transfer sulfur dioxide nitric oxide bubbling reactor euchlorine

Smad3 and its phosphoisoforms are prognostic predictors of hepatocellular carcinoma after curative hepatectomy

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Hepatobiliary & Pancreatic Diseases International 2012年第1期11卷 51-59页

作者： Seok-hyung Kim Soomin Ahn Cheol-keun Park Department of Pathology Samsung Medical CenterSungkyunkwan University School of Medicine

BACKGROUND:Progression of hepatocellular carcinoma (HCC) often leads to vascular invasion and intrahepatic metastasis,which correlate with recurrence after surgical treatment and poor *** may be an unusual cancer affected by continuous inflammation that can lead to consistent upregulation of transforming growth factor-β (TGF-β).Chronic inflammation shifts hepatocytic TGF-β signaling from the tumor-suppressive pSmad3C pathway to the oncogenic pSmad3L *** this study,we investigated the functional roles of Smad3 and its phosphoisoforms in the progression of ***:Tumor tissue microarrays of samples from 272 HCC patients who underwent curative surgical resection were used to detect the expression of Smad3,Smad4,pSmad3C (S423/425),pSmad3L (T179),pSmad3L (S204),and pSmad3L (S213).Disease-specific death was defined as 1) tumor occupying more than 80% of the liver,2) portal venous tumor thrombus (PVTT) proximal to the second bifurcation,3) obstructive jaundice due to tumor,4) distant metastases,or 5) variceal hemorrhage with PVTT proximal to the first *** the time of analysis,tumor recurrence was detected in 184 (67.6%) patients,and 96 (35.3%) had died of ***:Nuclear and cytoplasmic localization of Smad3,and nuclear localization of Smad4 were observed in 18.0%,9.9%,and 9.2% of HCCs,*** rates of Smad3 phosphoisoform-immunoreactive HCC varied according to the location of phosphorylation:pSmad3C (S423/425) 8.1%,pSmad3L (T179) 2.6%,pSmad3L (S204) 2.2%,and pSmad3L (S213) 10.3%.Multivariate analyses revealed that pSmad3C (S423/425) (P=0.022) was an independent predictor of longer recurrence-free ***3L (S213) (P=0.006),intrahepatic metastasis,multicentric occurrence,and liver cirrhosis were independent predictors of shorter recurrence- free *** Smad3 (P=0.006),larger tumor size,and intrahepatic metastasis were independent predictors of shorter disease-specific *** pSmad3L (S213) did not sh

关键词： Smad3 pSmad3C (S423/425) pSmad3L (S213) hepatocellular carcinoma hepatectomy survival

Bitmap lattice index in road networks

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Journal of Central South University 2014年第10期21卷 3856-3863页

作者： Doohee song keun-Ho Lee Kwangjin Park Information Communication Engineering Wonkwang University Division of Information Communication Engineering Baekseok University

A novel technique called the bitmap lattice index(BLI) is proposed, which combines the advantages of a wireless broadcasting environment with a road network. Existing road networks are based on the on-demand method: a server's workload increases as the query request increases when a server sends a client information. To solve this problem, we propose the BLI. The BLI denotes an object and a node as 0 and 1 in the Hilbert curve(HC) map. The BLI can identify the position of a node and an object through bit information; it can also reduce the broadcasting frequency of a server by reducing the size of the index, thereby decreasing the access latency and query processing times. Moreover, the BLI is highly effective for data filtering, as it can identify the positions of both an object and a node. In a road network, if filtering is done via the Euclidean distance, it may result in an error. To prevent this, we add another validation procedure. The experiment is conducted by applying the BLI to kNN query, and the technique is assessed by a performance evaluation experiment.

关键词： road network wireless broadcast spatial query bitmap lattice index(BLI)

Comparative fish community structure among different types of enclosures of estuarine environments

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Aquaculture and Fisheries 2022年第3期7卷 336-344页

作者： Sunwan Hwang keun-hyung Choi Marine Bio-Resources Research Unit KIOSTBusan49111Republic of Korea Department of Ocean Environmental Sciences Chung-Nam National UniversityDaejeon34134Republic of Korea

This study explores the differences of fish assemblages in three macrotidal estuaries of Man-gyeong River Estuary(MRE),Geum River Estuary(GRE),and Han River Esturay(HRE)with similar ranges of seasonal water temperature that are diked with different levels of disconnection from freshwater *** distribution of major species in the three estuaries could generally be grouped into three distinctive patterns based on their cumulative distribution with respect to the salinity *** MRE was geographically closer to the GRE than to the HRE,but the fish community of the MRE more closely resembled that of the *** freshness of the water inside the dike and the limit of coastal fish to the river may have led to this *** results provide clues to how enclosure patterns of estuarine waters could affect fish communities over a long-term *** addition,the information may provide guidance for how a fish community may return once environmental conditions are restored.

关键词： Fish community Diking Cumulative distribution Estuary Habitat connectivity