• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.391-397
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• 2011

The use of Hydrogen as a fuel is receiving considerable attention and as a result, research on novel methods of hydrogen production is necessary so that the hydrogen demands in the future can be satisfied. This study presents experimental data on methanol Autothermal Reformation that quantifies the relationship between the oxygen-to-methanol ratio ($O_2/CH_3OH$) and reformer efficiency. For each catalyst configuration, the $O_2/CH_3OH$ was varied from 0.1 to 0.4, with an increment of 0.05, to investigate the effects of $O_2/CH_3OH$ on the reactor performance, including temperature profile, conversion, and efficiency. $O_2/CH_3OH$ was increased from 0.15 to 0.20, and the catalyst bed temperature increased by $235^{\circ}C$ to approximately $550^{\circ}C$. The catalyst bed temperature increased with increasing $O_2/CH_3OH$ as the reaction shifted from endothermic to exothermic reaction and as a result, excess heat, which raised the reactor temperature, was generated. The reactor performance was shown to be highly dependent on $O_2/CH_3OH$. The optimum $O_2/CH_3OH$ = 0.30 found in the experimental tests is 30% higher than the theoretical optimum of 0.23. This is attributed to a combination of factors such as the concentrations of the $O_2$ and $CH_3OH$ gas, reaction rate, catalyst effects, heat loss from the reactor, and the difference between the actual amounts of reaction products formed and the theoretical amounts of the reaction products.

• Polymer(Korea)
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• v.25 no.4
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• pp.468-475
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• 2001

For copolymerization of ethylene and norbornene initiated by various metallocene catalysts such as $rac-Et(Ind)_2ZrCl_2,\;rac-Me_2Si(Ind)_2ZrCl_2,\;rac-Me_2Si(Cp)_2ZrCl_2,\;and\;(n-BuCp)_2ZrCl_2$ with modified methylaluminoxane(MMAO) cocatalyst, the ${\alpha}$-olefins such as 1-hexene(H), 1-octene and 1-decene were added as a 3rd monomer. In this situation, the effects of the polymerization condition, the catalyst structure as well as the structure and the amount of added ${\alpha}$-olefin on the catalyst activity as well as the properties and structure of polymer were examined. As results, it was found that the catalyst activity and thermal property of polymer depended on not only catalyst structure but also ${\alpha}$-olefin structure. For $rac-Et(Ind)_2ZrCl_2/MMAO$ catalyst system, it was possible to get high activity and controllable $T_g$ of polymer. Among ${\alpha}$-olefins, H as a 3rd monomer exhibited the maximum enhancement in catalyst activity.

• Journal of Soil and Groundwater Environment
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• v.11 no.3
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• pp.59-65
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• 2006

Reductive dechlorination of chlorophenols by nickel coated iron was investigated to understand the feasibility of using Ni/Fe for the in situ remediation of contaminated groundwater. Zero valent iron (ZVI) was amended with Ni(II) ions to form bimetal (Ni/Fe). Dechlorination of 4-chlorophenol and formation of intermediates was studied using Ni/Fe. Effects of initial contaminant concentration, bimetal loading, presence of humic acid, and solution chemistry were also evaluated. Experimental results showed that Ni/Fe bimetal was so effective that more than 95% of 4-CP degradation was achieved within 240 minutes. Pseudo first-order rate constant for the dechlorination reaction was well correlated with bimetal loading. Humic acid competed for the reactive sites on the nickel coated iron with chlorophenols, lowering the dechlorination efficiency. No significant changes in solution pH were observed in the dechlorination of chlorophenols with Ni/Fe in the absence of buffer, indicating that reactivity of bimetal (Ni/Fe) could be prolonged. Phenol was found as a dechlorination intermediate of the conversion of 4-chlorophenol compound by Ni/Fe.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.372-379
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• 2020

Ammonia-hydrogen dual-fuel engine is a way to reduce greenhouse gas emission because ammonia and hydrogen are carbon-free fuels. In ammonia-hydrogen dual-fuel engine, hydrogen is supplied to improve the combustion characteristic of ammonia. In this study, an ammonia reformer was developed to supply hydrogen for 10 kW class ammonia-hydrogen dual-fuel engine. Thermodynamic characteristic and catalyst were investigated for ammonia reforming. Heat transfer was important for high ammonia conversion of ammonia reformer. 99% of ammonia conversion was obtained when 10 LPM of ammonia and 610℃ of hot gas were supplied to the ammonia reformer.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.727-730
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• 2009

Highly active and stable nano-sized Ni catalysts supported on MgO-$Al_2O_3$ calcined from hydrotalcite-like materials have been successfully developed with a strong metal to support interaction (SMSI) to enhance the coke resistance in combined $H_2O$ and $CO_2$ reforming of $CH_4$ (CSCRM) for syngas ($H_2$/CO=2) production. The change of the surface area and NiO crystallite size with varying the pre-calcination temperature of support and Mgo content was investigated in relation to the coke resistance. As increasing the pre-calcination temperature, the surface area decreases and the metal to support interaction becomes weak. As a consequence, the coke deposition was more severe on catalysts pre-calcined at high temperature. It was concluded that highly dispersed Ni metal in the surface of Ni/MgO-$Al_2O_3$ catalyst (MgO=30 wt%) pre-calcined at $800^{\circ}C$ had a strong metal to support interaction (SMSI) resulting in an increase of coke resistance and high activity.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.1
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• pp.69-80
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• 2003

Nickel catalyst has been used for natural gas reforming with carbon dioxide, In this study, catalyst support used was HY zeolite. The optimum loading of Ni in the catalysts was 13 wt%. The effect of promoters, such as Mg, Mn, and K, was also studied. The addition of promoters to Ni catalyst improved the stability of catalysts and carbon deposition on Ni catalyst was suppressed. The reforming reactivity of promoter-added Ni catalyst was higher than that of Ni catalyst without any promoters. SEM, XRD, BET, TGA and FTIR tests were tried to characterize the catalyst structure before and after reaction.

• Journal of Biomedical Engineering Research
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• v.20 no.6
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• pp.547-553
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• 1999

생체재료로 사용되는 polyurethane(PU) 표면에 항혈전성 lumbrokinase(LK)를 고정함으로써 생체적합성을 향상시키고자하였다. 먼저 LK를 PU 표면에 고정하기 위한 가교제로서 4-azidoaniline hydrochloride와 poly(acrylic acid)를 이용하여 4-azidophenyl 작용기가 amido 결합으로 치환된 수용성, 광반응성 poly(acrylic acid)(PPa-II)를 합성하였다. H-nuclear magnetic reasonance spectrum(500MHz H-NMR)의 6-7 peak와 infrared spectrum (FT-IR) 의 2125.48 cm peak으로부터 PPA-II의 합성을 지원하였다. EH한 4-azidophenyl 작용기가 poly(acrylid acid) 잔기에 치환된 정도는 UV/VIS adpectrophotometric spectrum을 확인한 결과 11~14%임을 알 수있었다. 0.5 1및 5% PPA-II를 각각 광반응하여 얻은 PU는 39.5, 161.8 및 181.5 nmole/$\textrm{cm}^2$의 농도로 표면에 carvoxyl 작용기가 유도되었음을 알 수있었다. 0.05M KH2PO4 (pH 4.5) 용액에서 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide(EDC)를 촉매로 사용하여 LK를 PU표면에 amido 공유결합으로 고정하였으며, 이것은 지속적인 fibrinolytic 활성도를 보였다. PPA-II를 이용한 표면 개질 방법은 수용성 반응조건에서 이루어진다는 점과 광반응을 이용함으로써 특정부위에서의 표면개질이 가능하다는 점에서 그 응용가치가 크며 아울러 PU의 생체적합성을 향상시킬 수 있는 방법으로서 판단된다.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.973-978
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• 1997

The toughness and morphology of epoxy resin based on diglycidyl ether of bisphenol A(DGEBA) cured with of tris (dimethylaminomethy]) phenol(DMP-30) and castor oil (CO) as a toughening modifier have been studied. Mixtures of CO and an epoxy resin showed a higher miscibility than the classical CTBN modified epoxy resin. The glass transition temperature($T_g$) was decreased with the CO content and the cure temperature. It is interpreted that the networks of epoxy matrix obtained at high temperature are apparently looser and more flexible due to the lower crosslinking density. The toughness was slightly increased with the CO content at $40^{\circ}C$ of curing temperature. The toughness increased with increasing the cure temperature and CO content.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.1
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• pp.60-68
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• 2009

The steam reformer for hydrogen production from methane is studied by a numerical method. Langmuir- Hinshelwood model is incorporated for catalytic surface reactions, and the pseudo-homogeneous model is used to take into account local equilibrium phenomena between a catalyst and bulk gas. Dominant chemical reactions are Steam Reforming (SR) reaction, Water-Gas Shift (WGS) reaction, and Direct Steam Reforming (DSR) reaction. The numerical results are validated with experimental results at the same operating conditions. Using the validated code, parametric study has been numerically performed in view of the steam reformer performance. As increasing a wall temperature, the fuel conversion increases due to the high heat transfer rate. When Steam to Carbon Ratio (SCR) increases, the concentration of carbon monoxide decreases since WGS reaction becomes more active. When increasing Gas Hourly Space Velocity (GHSV), the fuel conversion decreases due to the heat transfer limitation and the low residence time. The reactor shape effects are also investigated. The length and radius of cylindrical reactors are changed at the same catalyst volume. The longer steam reformer is, the better steam reformer performs. However, system energy efficiency decreases due to the large pressure drop.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.75-81
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• 2007

Steam reforming of methane using Xe-arc solar simulator was studied for the application of concentrated solar energy into chemical reaction. The reactor, a volumetric absorber, consisted of a porous ceramic foam disk coated with commercial reforming catalyst. Operating temperature was in the range of $450\;-\;550^{\circ}C$ and the excess steam ratio to methane was from 3.0 to 5.0. At the steady-state condition, the conversion of methane Increased with temperature in the range of 15 % - 30 % and the experimentally determined conversion was found to be close to theoretical equilibrium conversion. It was also found that the CO selectivity slightly decreased with excess steam ratio. Finally, the conversion of methane decreased significantly with space velocity of reactants.