• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.410-415
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• 1996

It is well known that the heavy water separation process using hydrogen isotope exchange reaction over the platinum catalyst is the most efficient. In this study, the Pt/silicalite catalysts were prepared and characterized by hydrogen adsorption in order to develop the hydrophobic platinum catalyst for hydrogen isotope exchange reaction. Silicalite was synthesized as support material and it was verified that silicalite is more hydrophobic than activated carbon and ZSM-5. Also the platinum was loaded on silicalite by conventional impregnation and ion-exchange method respectively. The platinum dispersion of Pt/silicalite catalysts was measured through hydrogen adsorption experiment. The dispersion is very low in the catalyst prepared by the impregnation method while it is very high with limited platinum content in the catalyst prepared by the ion-exchange method.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.213-217
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• 2007

Decomposition of benzene and selectivity of byproducts were investigated by using Dielectric Barrier Discharge (DBD) at atmospheric pressure. In order to increase the decomposition rate and selectivity of byproducts, two types of catalysts, H-ZSM-5 and Na-Y, were optionally employed inside the reactor of the process. The decomposition efficiency of benzene was investigated on the DBD and DBD/catalyst systems at various processing parameters including discharge voltage, residence time, and concentration of benzene. The results showed that, compared with the DBD only, the catalyst-assisted DBD process as a hybrid discharge type had an improved decomposition efficiency at the same process conditions of discharge voltage and residence time

• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.323-327
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• 2011

A zeolite sheet (ceramic paper containing zeolite) made in a cylindrical configuration can be applied to a honeycomb rotor for the effective VOC removal. In this study, the zeolite sheet containing ZSM-5 was used as a support for Pt-loading, and its catalytic activity for the toluene combustion reaction was compared with those of the other Pt catalysts loaded on ${\gamma}-Al_2O_3$ and cordierite honeycomb. Pt/zeolite sheet catalyst showed a higher activity for toluene combustion reaction than that of $Pt/{\gamma}-Al_2O_3$ or Pt/cordierite honeycomb. On the other hand, the dispersion of Pt particles loaded on the zeolite sheet was improved by the pretreatment with $NH_3-H_2O$ vapor at room temperature. Consequently, the pretreatment of Pt/zeolite sheet by $NH_3-H_2O$ vapor significantly enhanced the catalytic activation for toluene combustion reaction.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.547-555
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• 2021

A catalyst-plasma reactor was applied to the storage of agricultural products, e.g., apple and kiwi, to remove the ethylene generated during the storage. Two 1-m³ unit containers were prepared, and the long-term storage stability of the control group at room temperature was compared with that of the experimental group of which the produced ethylene was treated by the catalyst-plasma reactor. In case of the experimental group, a small amount of ozone was injected to the unit container to suppress the growth of microorganisms such as mold. The apples and kiwis were stored at room temperature for 50 and 57 days, respectively, and the changes in ethylene concentration, hardness, sugar content, acidity, and loss rate were compared. The ethylene concentration during the storage for the control group was higher than that for the experimental group, indicating that the ethylene was effectively removed. Hardness, sugar content, and sugar acid ratio after the storage were better than before the storage, and in particular, the storage stability of kiwifruit was improved significantly. In addition, after the storage, the loss rates of apples and kiwis in the control group were 10 and 54.1%, respectively, but the loss rates in the experimental group were 6 and 34.8%, respectively. Therefore, the storage stability of the experimental group was a lot better than that of the control group.

• Clean Technology
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• v.19 no.3
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• pp.327-332
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• 2013

Space- and time-resolved in-situ optical and fluorescence microspectroscopy techniques have been applied to investigate the coke formation during aromatization of C5 paraffin and olefin over H-ZSM-5 crystal. In-situ UV/vis absorption measurement offers space- and time-resolved information for the coke formation. Different coking trends have been observed with respect to the location of a crystal as well as the reactant types. From in-situ confocal fluorescence microspectroscopy study, it is revealed that the concentration of certain species photo-excited at 488 nm becomes high at the central region, whereas the compounds emitting fluorescence by 561 nm laser move towards the boundary region of the crystal. The different fluorescence patterns obtained varying excitation lasers suggest the existence of distinct fluorescence emitting species having different degree of coke growth.

• Journal of Aerospace System Engineering
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• v.11 no.2
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• pp.9-15
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• 2017

In order to verify the possiblity of improving the combustion performance of ethanol using zeolite catalyst and the characteristics of nitrogen oxides and carbon monoxide emission, micro gas turbine experiments were performed using catalytic reaction products, ethanol and kerosene as fuels and the results were compared. The thrust of the catalytic reaction product was lower than that of kerosene, but it was improved by 5% on average compared with the use of ethanol. Nitrogen oxides and carbon monoxide emissions of the catalytic reaction products were measured to be very low overall compared to kerosene. As a result, when the ethanol was reformed using the zeolite catalyst, the engine performance could be improved while maintaining the environment friendliness of the ethanol.

• Journal of the Korea Convergence Society
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• v.10 no.4
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• pp.131-138
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• 2019

Diesel engines have important advantages over its gasoline counterpart including high thermal efficiency, high fuel economy and low emissions of CO, HC and $CO_2$. However, NOx reducing is more difficult on diesel engines because of the high $O_2$ concentration in the exhaust, marking general three way catalytic converter ineffective. Two method available technologies for continuous NOx reduction onboard diesel engines are Urea-SCR and LNT. The implementation of the Urea-SCR systems in design engines have made it possible for 2.5l and over engines to meet the tightened NOx emission standard of Euro-6. In this study, we investigate the characteristics of NOx reduction with respect to engine speed, load, types of catalyst and the $NH_3$/NOx ratio and present the conditions which maximize NOx reduction. Also we provide detailed experimental data on Urea-SCR which can be used for the preparation for standards beyond Euro-6.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.18-23
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• 2002

Recently, as people pay attention to the environmental pollution, the emission of diesel engine has become a serious problem. Diesel Oxidation Catalysts(DOC) were experimentally investigated for the purification of pollutants exhaust emission from the diesel engine. In this study, the conversion efficiency of exhaust gas was investigated with various washcoat materials of the DOC. It was formed that CO conversion efficiency depended on temperature, but THC conversion was dominated by temperature and space velocity. Conversion efficiency of THC and CO increased with the addition of ZSM-5 in the washcoat, whereas these conversion efficiency decreased by adding Nd and Ba additives. $V_2O_5$ additive had the thermal stability for high temperature. Thermal durability of the catalyst was improved as increase of $V_2O_5$ additive.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1327-1330
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• 2011

Dehydration of 1-phenylethanol to produce styrene has been studied in liquid phase with three solid acid catalysts such as H-ZSM-5, H-Y and Amberlyst-15. Amberlyst-15 shows the highest conversion and styrene yield, suggesting the applicability of a resin catalyst in the dehydration. The good performance of the Amberlyst-15 may be due to high acid concentration and ready diffusion of reactants and products. A possible reaction scheme (such as the formation of styrene from diphenylethylether) has also been suggested.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1070-1078
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• 1998

Thermodynamic analysis on carbon dioxide reforming of methane was performed using a computer program which can handle condensed species in the products, and the reforming experiments were conducted over $Al_2O_3$, $La_2O_3$, ZSM-5, MCM-41, KIT-1 supported nickel catalysts, and a commercial ICI 46-1. It was estabished that a system which consists of $CH_4$, $CO_2$, CO, $H_2$, $H_2O$, and C is appropriate for theoretical equilibrium calculations and addition of water vapor or oxygen was found to diminish the contribution of carbon dioxide in reforming. Silicate molecular sieve-supported catalysts such as Ni/ZSM-5, Ni/MCM-41, Ni/KIT-1 were effective for high $CH_4$ and $CO_2$ conversions as well as for high CO yield. Coke formation was suppressed when CaO was added as a promoter. Ni/Ca/KIT-1 which contains 10% Ni with 3% Ca showed conversion approaching equilibrium levels above $650^{\circ}C$ and maintained constant activity over 20 h. Despite increased space velocity, relatively high conversion and CO yield were observed.