• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.77-78
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• 2015

산업화로 인하여 토지의 사막화, 물부족, 오존층 파괴, 지구 온난화 등 많은 환경문제가 발생되었으며 아직 진행 중에 있다. 이에 UN에서는 환경 규제를 강화하였으며 국제해사기구(IMO:International Maritime Organization)에서는 선박의 배기가스 규제 강화를 위하여 NOx(질소산화물) 및 SOx(황산화물)의 배기량을 줄이도록 하고 있으며 2016년부터는 본격적으로 규제하려 하고 있다. 상기의 규제 물질 중 NOx를 제거하는 선택적환원촉매(SCR:Selectivity Catalytic Reduction) 시스템은 선박의 배기가스가 지나가는 통로에 요소수(Urea)를 분무하여 $260^{\circ}C$ 이상의 높은 온도에서 요소수에 있는 암모니아가 배기가스에 있는 NOx와 반응, 결합함으로서 NOx를 질소와 산소로 분리, 제거하는 방식이다. 하지만 선박의 경우 대부분 엔진이 2행정으로 배기가스 온도가 일반적으로 $180^{\circ}C{\sim}220^{\circ}C$이기 때문에 요소수에 있는 암모니아가 배기가스에 있는 NOx와 반응하지 않아 환원률이 높지 않다. 이에 우리는 초미세기포를 이용하여 낮은 온도에서도 반응할 수 있는 요소수 및 요소수 활성화 기기를 개발하여 상기의 문제점들을 최소화 할 수 있도록 하였다. 또한 SCR 시스템의 점성유동해석을 통하여 보다 효율적인 SCR 시스템의 개발을 할 수 있도록 기여하였다.

• 플랜트 저널
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• 제9권3호
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• pp.48-52
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• 2013

본 연구에서는 전산유체해석(CFD)을 통하여 SCR 탈질설비 내부의 유동장 흐름을 전산모사하였다. 또한 유동장의 균일도를 분석하기 위해 기존 설비에 대한 해석을 수행하였으며 이를 통해 문제점을 도출하고 개선하였다. 개선방안으로는 곡관에 guide vane을 설치하여 곡관상에 기류를 균일하게 안내해 주었으며, baffle을 설치하여 SCR설비로 초기 유입된 기류의 균일한 공간 분포를 도출하였다. 마지막으로 porous plate를 baffle 하단에 설치하여 균일류 형성의 최적화 모델을 도출하였다.

• 한국수소및신에너지학회논문집
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• 제25권4호
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• pp.425-435
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• 2014

Simulation studies on catalytic methanation reaction in externally cooled tubular reactor filled with monolithic catalysts were carried out using a general purpose modelling tool $gPROMS^{(R)}$. We investigated the effects of operating parameters such as gas space velocity, temperature and pressure of feeding gas on temperature distribution inside the reactor, overall CO conversion, and chemical composition of product gas. In general, performance of methanation reaction is favored under low temperature and high pressure for a wide range of their values. However, methane production becomes negligible at temperatures below 573K when the reactor temperature is not high enough to ignite methanation reaction. Capacity enhancement of the reactor by increasing gas space velocity and/or gas inlet pressure resulted no significant reduction in reactor performance and heat transfer property of catalyst.

• 한국세라믹학회지
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• 제35권10호
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• pp.1070-1077
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• 1998

Effect of current collecting layer on the cathode was characterized by AC impedance spectroscopy at 800$^{\circ}C$ under flowing air. LSM-YSZ composite cathode showed lower polarization resistance due to the in-crease of triple phase (LSM/YSZ/Pore) boundary length by incorporation of YSZ. Ohmic resistance {{{{ {R }_{1 } }} of LSM-YSZ was higher than that of pure LSM however because in-plane resistance of the cathode was fair-ly high due to its high specific resistivity. To reduce the in-plane resistance of LSM-YSZ cathode cathode side current collecting layer was required. Ohmic resistance {{{{ {R }_{1 } }} was reduced after forming LSM current col-lecting layer on the LSM-YSZ cathode. In case of pure LSM cathode the formation of Pt, or LSCO current collecting layer reduced polarization resistance {{{{ {R }_{p } }} but ohmic resistance {{{{ {R }_{1 } }} was relatively constant. After annealing of LSM cathode with Pt current collector at higher temperature polarization resistance {{{{ {R }_{p } }} was in-creased but ohmic resistance {{{{ {R }_{1 } }} was constant. These phenomena indicate that Pt or LSCo current col-lecting layers act as a catalytic layer for oxygen reduction of pure LSM cathode. LSCO current collector was effective in reducing the ohmic and polarization resistance of LSM-YSZ cathode.

• 센서학회지
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• 제19권3호
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• pp.176-183
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• 2010

It is considered that the urea injection DeNOx SCR(selective catalytic reduction) system is the only promising method to satisfy the worldwide NOx emission standards. As for the theoretical aspect, reactants of NO and $NO_2$ with $NH_3$ produce $H_2O$, $N_2$ and $O_2$ which do not harm human beings and environmental as well. The realization of maximum NOx conversion (without using a post oxidation catalyst) is only possible with closed loop controlled urea dosing. It means built-in $NH_3$ gas sensor have to be developed for detecting accurate $NH_3$ concentration for the feedback system. Using YSZ(yttria-stabilized zirconia) as a solid state electrolyte and $In_2O_3$ as a sensing material, this paper aims to study dependable $NH_3$ gas sensor for the promising solution of DeNOx technology, which have a reproducible electric output signal, a high sensitivity and fast response.

• Environmental Engineering Research
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• 제10권3호
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• pp.131-137
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• 2005

The catalytic activity of precious metals(Rh, Pd, Pt) and nickel catalysts supported on ${\gamma}-Al_2O_3\;and\;CeO_2$ in the partial combustion of methane(PCM) to syngas was investigated based on the product distribution in a fixed bed now reactor under atmospheric condition and also on analysis results by SEM, XPS, TPD, BET, and XRD. The activity of the catalysts based on the syngas yield increased in the sequence $Rh(5)/CeO_2{\geq}Ni(5)/CeO_2>>Rh(5)/Al_2O_3>Pd(5)/Al_2O_3>Ni(5)/Al_2O_3$. Compared to the precious catalysts, the syngas yield and stability of the $Ni(5)/CeO_2$ catalyst were almost similar to $(5)/CeO_2$ catalyst, and superior to these of any other catalysts. The syngas yield of $Ni(5)/CeO_2$ catalyst was 90.66% at 1023 K. It could be suggested to be the redox cycle of the successive reaction and formation of active site, $Ni^{2-}$ and the lattice oxygen, $O^{2-}$ produced due to reduction of $Ce^{4-}$ to $Ce^{3-}$.

• 분석과학
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• 제16권3호
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• pp.198-205
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• 2003

쿠페론은 nitrosophenylhydroxylamine의 ammonium salt로서 흡착촉매 벗김법 (AdCtSV)에서 리간드의 역할을 하고 동시에 촉매 역할을 한다고 알려져 있다. 순환 전압전류법을 이용하여, 1 mM 인산염 완충용액에서 오스뮴-쿠페론 착물의 전기화학적 행동을 살펴보았다. 오스뮴 정량의 최적 조건은 1 mM 인산염 완충용액 (pH 6.0), 0.1 mM 쿠페론의 용액에서 주사속도는 100 mV/s 이었다. 이 조건에서 농도 변화에 따른 선형 주사 전압곡선의 환원 봉우리 전류변화를 이용하여 얻은 오스뮴의 검출 한계 ($3{\sigma}$)는 $1.0{\times}10^{-7}M$이다.

• 분석과학
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• 제13권1호
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• pp.1-4
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• 2000

로듐이 미량으로 존재할 때 펄스차이 폴라로그래피로 정량할 수 있는 용액조건을 확립하였다. 포름알데히드 0.004%(w/v)-염산 0.75M의 조건에서 가장 예민한 수소촉매파를 얻을 수 있었다. 이 조건에서 검출한계는 $7.0{\times}10^{-12}M$이고 봉우리 전류가 선형인 농도범위는 $1.0{\times}10^{-11}{\sim}1.0{\times}10^{-8}M$이었다. 이 농도범위에서 다른 백금족 원소가 500배까지 존재하여도 방해를 받지 않았다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권3호
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• pp.306-312
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• 2005

IMO $NO_x$ levels are generally possible to meet by means of primary on-engine measures. Further significant follow-on reductions are likely to require a secondary after-treatment technique. SCR(Selective Catalytic Reduction) technology is used almost exclusively for $NO_x$ removal in stationary combustion systems. In order to develop a practical SCR system for marine application on board ship, a primary SCR system using urea was made. The SCR system was set up on the ship, 'HANNARA' as a test vessel. employed a two-stroke cycle diesel engine as main propulsion, which is a training ship of Korea Maritime University. The purpose of this paper is to report the results about the basic effects of the below system parameters, The degree of $NO_x$ removal depends on some parameters, such as the amount of urea solution added, space velocity, reaction gas temperature and activity of catalyst.

• Journal of Photoscience
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• 제6권3호
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• pp.91-96
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• 1999

Zeolites and microporouos materials continue to attract attention as novel hosts for photochemical reactions. Zeolities are attractive because of their ability to selectivity exchange and incorporate species within the void spaces and interconnecting channels, providing a spatial arrangement of molecules. Our research has primarily focused on intrazeolitic electron transfer from excited Ru(bpy)32+ in supercages of zeolite Y to a series of bipyridinium ions. In the Ru(bpy)32+ viologen-zeolite Y samples, the slowing of the back electron transfer from the bipyridinium radical cation to Ru(bpy)32+ allows for charge propagation via self exchange between diquat molecules. This provides an opportunity for permanent charge separation. When the migrating charge on the diquat radical within the zeolite reaches the surface, it can be transferred to a neutral viologen (PVS) in solution, resulting in permanent charge separation. The advantage of long-lived charge separation can be exploited for useful chemistry if suitable catablysts can be assembled on the zeolities. We have studied Ru(bpy)2 as water oxdiation catalysts. We have demonstrated that synthesis of RuO2 fibers on a zeolite via thermal decomposition of Ru3(CO)12 leads to the most active water decomposition catalyst reported to date. Because of the extensive interest of photochemical water reduction to H2, much is known about catalytic systems usin gone electron catalyst, and even more importantly, that no reaction of viologen occurred with H2 over this catalyst. The present challenge is to incorporate all these elements of the system into an architecture and we are examining zeolite membranes for this purpose.