• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1329-1336
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• 2007

This study was carried out to develop an efficient process abating high NO concentration. A hybrid process of selective catalytic reduction(SCR) and activated carbon fiber(ACF) adsorption was newly designed and tested. Used ACF in NO adsorption was regenerated by simultaneously applying heat and vacuum. The result of ACF regeneration was for superior in the desorption condition at $140^{\circ}C$ and vacuum 600 mmHg. A commercial catalyst was used at the conditions of reaction temperature at $300^{\circ}C$, $NH_3/NO$ mole ratio = 1.0 for SCR process. NO evolved from ACF regeneration reactor could be removed by SCR reactor up to 98%. But high concentration of NO was exhausted from SCR reactor for one minute when the flue gas of NO 300 ppm and deserted NO from ACF regeneration were simultaneously treated by the same SCR reactor. Therefore, it is necessary to use additional small sized SCR reactor or to increase $NH_3$ concentration for a short time along with NO concentration rather than to mix flue gas with the gas evolving from ACF regeneration at fixed $NH_3$ inlet concentration. The hybrid process of SCR and ACF showed high NO removal efficiency over 80% at any time courses. Through the repeated cycles, stable DeNOx efficiency was maintained, indicating that the hybrid process would be a good countermeasure to the spotaneously high NO concentration instead of increasing the SCR capacity.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.443-448
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• 2015

A swirl type mixer was developed to improve the flow mixing performance of a marine selective catalytic reduction system. In this study, the swirl type mixer and a multi-staged swirl type mixer, in which the angle of the vanes at each stage is controllable were considered to provide the optimal region of angles for the mixers. The effects of the vane angles in both mixers on the uniformity index and pressure drop were investigated using a computational fluid dynamics simulation. In the swirl type mixer, the optimal conditions for the flow mixing performance were observed at vane angles from 30 to 60 degrees when vane angles could be adjusted between 10 to 80 degrees, however, the pressure drop increased continually with increasing vane angle of the mixer. On the other hand, control of the individual staged angles of the multi-staged mixer showed that it is possible to keep enhancing flow mixing performance while reducing the pressure drop.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.479-485
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• 2011

Pt-Bi/C catalysts supported on carbon black with various Pt/Bi ratios were synthesized by a reduction method. Chloroplatinic acid hydrate ($H_2PtCl_6{\cdot}xH_2O$) and bismuth (III) nitrate pentahydrate ($Bi(NO_3)_3{\cdot}5H_2O$) were used as precursors for Pt and Bi, respectively. Before loading metal on carbon, heat treatment and pretreatment of carbon black in an acidic solution was conducted to enhance the degree of dispersion. The physical property of the synthesized catalysts was investigated by X-ray diffraction and X-ray photoelectron spectroscopy. The XRD pattern of untreated Pt-Bi/C catalyst showed BiPt and $Bi_2Pt$ peaks in addition to Pt peaks. These results imply that Bi atoms were incorporated into the Pt crystal lattice by Pt-Bi alloy formation. The catalytic activity for methanol oxidation was measured using cyclic voltammetry in a mixture of 0.5 M $H_2SO_4$ and 0.5 M $CH_3OH$ aqueous solution. The addition of proper amount of Bi was found to significantly improve catalytic activity for methanol oxidation. The catalytic activity for methanol oxidation was closely related to the stability between electrode and electrolyte. In order to investigate the stability of catalysts, chronoamperometry analysis was carried out in the same solution at 0.6 V.

• Journal of Surface Science and Engineering
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• v.54 no.1
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• pp.1-11
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• 2021

Porous dendrite structure AuCu alloy was formed using a hydrogen bubble template (HBT) technique by electroplating to improve the catalytic performance of gold, known as an excellent oxygen reduction reaction (ORR) catalyst in alkaline medium. The rich Au surface was maximized by selectively electrochemical etching Cu on the AuCu dendrite surface well formed in a leaf shape. The catalytic activity is mainly due to the synergistic effect of Au and Cu existing on the surface and inside of the particle. Au helps desorption of OH- and Cu contributes to the activation of O2 molecule. Therefore, the porous AuCu dendrite alloy catalyst showed markedly improved catalytic activity compared to the monometallic system. The porous structure AuCu formed by the hydrogen bubble template was able to control the size of the pores according to the formation time and applied current. In addition, the Au-rich surface area increased by selectively removing Cu through electrochemical etching was measured using an electrochemical calculation method (ECSA). The results of this study suggest that the alloying of porous AuCu dendrites and selective Cu dissolution treatment induces an internal alloying effect and a large specific surface area to improve catalyst performance.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.459-467
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• 2022

Redispersion of Pt-Sn particles in Pt, PtSn catalyst which have been sintered by high temperature hydrogen reduction was investigated using oxygen treatment with various temperatures. The aim of this study was to understand the relationship between the catalytic activity for propane dehydrogenation reaction and the change in the physicochemical properties of the catalyst. X-ray diffraction analysis (XRD), CO pulse chemisorption, and H₂ temperature programmed reduction (H₂-TPR) were performed to investigate the state of active metal and interactions between particles of redispersed catalyst. It was confirmed that the dispersion and particle size of platinum, the crystal phase of the catalyst, and the reduction behavior were changed according to the oxygen treatment. As for the catalytic activity in propane dehydrogeantion, sintered PtSn catalyst treated with oxygen at 500 ℃ showed best activity and recovery of initial activity. It was confirm that catalyst after oxygen treatment at 500 ℃ showed high dispersion of Pt and decreased particle size as the results of CO pulse chemisorption and XRD of catalyst, and thus the redispersion of PtSn particles in sintered catalyst was occurred. Catalytic activity was recovered due to redispersion using oxygen treatment, and the activity recovery of the PtSn catalyst was higher than that of Pt catalyst.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.475-476
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• 2007

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.261-262
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• 2002

산업용 보일러나 발전설비와 같은 대규모 고정원에서 다량 배출되는 NOx의 제거를 위한 여러 기술 중에서 현재 암모니아를 환원제로 사용하는 선택적 촉매 환원법(Selective Catalytic Reduction : SCR)이 가장 유망하며, 많은 연구와 더불어 선진국가에서 상업화되어 조업되고 있다. SCR 공정은 시설투자와 운전비가 비교적 저렴하고 높은 NOx 전환율(90%이상)과 폐수처리 등의 후처리 공정이 필요하지 않은 장점이 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.490-491
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• 2007

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.209-210
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• 1999

오존 precursor인 NOx의 배출기준은 점차 강화되고 있고 NOx의 처리기술로는 선택적 촉매환원법 (Selective Catalytic Reduction; SCR)이 가장 널리 사용되고 있다. 국내 SCR 적용공정의 경우, 100% 수입에 의존하고 있어 support 촉매의 국산화가 절실히 요구되고있다. 이에 본 연구에서는 support로 섬유형 세라믹 필터를 사용하여 CuO, V$_2$O$_{5}$ 촉매를 담지시켜 NOx의 제거실험을 수행하였다.(중략)

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.181-182
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• 2006

최근 미주의 급격한 LNG 수요와 더불어 Safety, 환경 및 테러의 문제를 안고 있는 육상 LNG terminal의 대안으로 등장한 LNG Regasification Vessel의 시장 전망과 미주 지역의 엄격한 환경 규제를 만족시키기 위한 Regasification Vessel의 기술 동향에 대해 고찰하였다.