• 한국대기환경학회지
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• 제14권5호
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• pp.443-454
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• 1998

Pt-V catalytic converter was installed on a heavy duty diesel engine and the characteristics of the emission reduction were tested using a engine dynamometer at various operating conditions. The emission reduction performance of Pt-V catalyst was also compared with that of a commercialized Pt catalyst currently being used in some of the heavy duty diesel engines in advanced countries. The effects of Pt-V and Pt catalysts on regulated and unregulated emissions were investigated using a 0.05 weight percent sulfur content fuel with an engine dynamometer Experiments for gaseous emissions (CO, HC and aldehyde) as well as particulate emissions (TPM, SOF and sulfate) have been conducted at several operating conditions such as T-7 mode, D-13 mode and S-13 mode before and after installing the Pt-V and Pt catalysts in the exhaust system. The emission reduction performance of Pt catalyst with respect to CO, HC, SOF, PAHs and aldehyde was found to be a little higher than that of Pt-V catalyst, but the Pt catalyst showed innate disadvantage of causing an increase of PM due to the sulfate formation via high SO2 conversion at high exhaust temperature, especially above 45$0^{\circ}C$.

• 에너지공학
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• 제8권2호
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• pp.256-264
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• 1999

본 연구에서는 메탄의 부분산화반응에 미치는 base metal 의 영향을 살펴보기 위하여 6~l2wt%의 Mn, Cu, V, Co, Cr 그리고 Ba 등이 2 wt% Pt, 70 wt% Alumina, 28 wt% Ceria and Zirconia 와 함께 cordierite (2MgO.2Al$_2$O$_3$.5SiO$_2$)에 담지된 Pt-B/cordierite 촉매(B: base metal)를 사용하여 메탄의 부분산화반응 실험을 수행하였다. 메탄의 부분산화반응에 대한 활성은 Ba, Co그리고 Cr 담지 촉매는 Ni담지 촉매와 유사하게 Mn, Cu, V을 담지 했을 때 보다 우수한 것으로 나타났으나, 코크 생성에 대한 활성도 큰 것으로 나타났다. 또한 5wt% Ni/Al$_2$O$_3$촉매를 이용한 메탄의 부분산화반응 실험 후의 촉매에 대한 XRD 분석결과 Ni은 3가지 형태의 상으로 존재하는 것을 확인할 수 있었으며, 촉매층 전단에서는 주로 NiAl$_2$O$_4$와 NiO 형태로 존재하여 메탄의 산화반응이 일어나며, 그리고 촉매층 후단에서는 환원상태의 Ni로 존재는 것으로 보아 개질반응이 일어나는 것을 알 수 있었다.

• 공업화학
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• 제20권1호
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• pp.28-33
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• 2009

카본나노튜브에 담지된 몰리브데늄 카바이드 촉매를 다양한 제조 조건을 통해 제조하여 촉매특성을 분석하였고, 메탄올의 전기화학적 산화반응을 통해 촉매의 활성을 비교하였다. 촉매로써 전이금속의 낮은 활성을 극복하기 위한 방안으로 카본나노튜브를 지지체로 사용하였으며 전구체의 양 및 종류, 지지체의 산처리 방법, 탄화공정 온도조건 등을 변화하여 촉매를 제조하였다. 제조된 촉매는 ICP-AES, XRD, TEM을 통하여 촉매의 특성을 분석하였고, 메탄올의 전기화학적 산화반응을 통해 촉매의 활성을 비교하였다. 몰리브데늄 카바이드 촉매($Mo_2C/CNT$)의 다양한 제조방법으로 입자크기와 담지량을 변화시킬 수 있었으며, 입자의 크기와 담지량의 변화에 따른 전기화학적 산화반응의 특성을 설명할 수 있었다.

• 한국가스학회지
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• 제17권5호
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• pp.22-27
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• 2013

수소와 CNG를 혼합한 HCNG는 CNG에 비해 연소효율이 높고 보다 친환경적인 연료로 CNG 엔진의 다음 단계의 엔진으로 각광받고 있으며, 수소시대로의 가교역할을 할 것이라 전망된다. 2014년 EURO-6의 도입으로 CNG 및 HCNG 차량에서 발생되는 메탄가스에 대해서도 규제가 이루어질 전망이다. 본 연구에서는 HCNG 엔진의 배기가스 중 메탄가스를 저감하기 위한 메탄산화촉매를 다루었다. 메탄산화촉매의 장시간 운전에 따른 내구성 및 메탄산화 양상 등에 대해 연구했으며, 이 때 촉매의 화학적인 현상을 분석하기 위해 촉매의 중요한 인자인 귀금속 분산도, 비표면적 변화 등을 촉매 활성과 연계하여 연구하였다.

• Carbon letters
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• 제9권4호
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• pp.303-307
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• 2008

The studies on integrated operation of fuel cell with fuel processor are very essential prior to its commercialization. In this study, Polymer Electrolyte Membrane Fuel Cell (PEMFC) was operated with a fuel processor, which is mainly composed of two parts, methanol steam reforming reaction and preferential oxidation (PROX). In fuel processor, ICI 33-5 (CuO 50%, ZnO 33%, $Al_2O_3$ 8%, BET surface area: $66\;m^2g^{-1}$) catalyst and CuO-$CeO_2$ catalyst were used for methanol steam reforming, preferential oxidation (PROX) respectively. PEMFC was operated by hydrogen fuel generated from fuel processor. The resulting gas from PROX reactor is used to operate PEMFC equipped with our prepared anode and cathode catalyst. PtRu/C catalyst gives more tolerance to CO.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.71-80
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• 2012

To improve the $NO_X$ conversion over a SCR (selective catalytic reduction) catalyst, the DOC (diesel oxidation catalyst) is usually placed upstream of the SCR catalyst to enhance the fast SCR reaction ($4NH_3+2NO+2NO_2{\rightarrow}4N_2+6H_2O$) using equimolar amounts of NO and $NO_2$. Here, a ratio of $NO_2/NO_X$ above 50% should be avoided, because the reaction with $NO_2$ only ($4NH_3+4NO+O_2{\rightarrow}4N_2+6H_2O$) is slower than the standard SCR reaction ($4NH_3+4NO+O_2{\rightarrow}4N_2+6H_2O$). In order to accurately predict the performance characteristics of SCR catalysts, it is therefore desired to develop a more simple and reliable mathematical and kinetic models on the oxidation kinetics of nitric oxide over a DOC. In the present work, the prediction accuracy and limit of three different chemical reaction kinetics models are presented to describe the chemicophysical characteristics and conversion performance of DOCs. Steady-state experiments with DOCs mounted on a light-duty four-cylinder 2.0-L turbocharged diesel engine then are performed, using an engine-dynamometer system to calibrate the kinetic parameters such as activation energies and preexponential factors of heterogeneous reactions. The reaction kinetics for NO oxidation over Pt-based catalysts is determined in conjunction with a transient one-dimensional (1D) heterogeneous plug flow reactor (PFR) model with diesel exhaust gas temperatures in the range of 115~$525^{\circ}C$ and space velocities in the range of $(0.4{\sim}6.5){\times}10^5\;h^{-1}$.

• 한국환경보건학회지
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• 제23권1호
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• pp.34-42
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• 1997

A laboratory experiments were performed to investigate the treatment of photographic processing wastewater by chemical oxidation and biological treatment system. The effect of reaction conditions such as hydrogen peroxide dosage, ferrous sulfate dosage and pH on the COD removal in Fenton oxidation were investigated. The optimal dosage of hydrogen peroxide was 2.58 M and 3.87 M for the developing and fixing process wastewater, respectively. The Fenton oxidation was most efficient in the pH range of 3-5 and the optimal condition for initial reaction pH was 5 for a developing process wastewater. With iron powder catalyst, the COD for a developing process wastewater was removed in lower pH than with ferrous sulfate catalyst. The removal efficiency of COD for refractory compounds such as Diethyleneglycol, Benzylalcohol, Hydroxylamine Sulfate, Ammonium Thiosulfate, Ammonium Ferric EDTA and Disodium EDTA in the photogaphic wastewater was found than 90% except Potassium Carbonate. When the photographic processing wastewater after pretreatment by Fenton oxidation was treated with batch activated sludge process, the addition of $KH_2PO_4$ as a phosphorous compound improved the removal efficiency of COD. During the continuous biological treatment of developing and fixing process wastewater after pretreatment by Fenton oxidation, the effluent COD concentration less than 100 mg/l was obtained at 0.425 and 0.25 kgCOD/m$^3$.d, respectively.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.37-38
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• 2012

Two catalyst systems with different content of precious metal coated on DOC are carefully tested in a diesel engine to investigate the emission characteristics of $NO_2$. Three types of experiment methods ($NO_2$ conversion test, ETC mode test, and BPT test) are applied to compare the performance of the two catalyst systems. All the experimental results consistently indicate that it is possible to satisfy $NO_x$ regulation by properly lowering the content of precious metal without the loss of PM removal performance.

• 한국대기환경학회지
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• 제12권2호
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• pp.121-130
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• 1996

The catalysts composed of Pt, Pd and W as active-components, $Al_{2}O_{3}$ and $SiO_{2}$ as supports, were perpared on the honeycomb type substrate and characterized by BET, SEM, TGA, FT-IR and XRD for diesel emission control. CO, $C_{3}H_{6}$, and $SO_{2}$ oxidation was carried out over these catalysts in a fixed bed continuous flow reactor at the temperatures between 100-500.deg.C and reactant gas was composed of 10 vol.% $O_{2}$, 1 vol.% CO, 0.8 vol.% $C_{3}H_{6}$ and 88.2 vol.% $N_{2}$. It was found that under these experimental conditions, the CO, $C_{3}H_{6}$ oxidation activity of Pt-W catalyst was higher than that of any other prepared catalyst, and this catalyst had also a good inhibition effect on $SO_{2}$ oxidation. Also it was show that the influence of $SO_{2}$ on $Al_{2}O_{3}$ was more sever than that of $SO_{2}$ on $SiO_{2}$.

• 동력기계공학회지
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• 제5권2호
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• pp.13-21
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• 2001

Diesel emission control is being addressed worldwide to help preserve the global environment. This paper mainly deals with the effects of oxidation catalysts to reduce emissions from the automotive heavy-duty diesel engine. Two types of the oxidation catalyst with different kinds of precious material were used. An 11 litter displacement diesel engine with turbocharger was operated to evaluate DOC with various engine speed, load conditions under D-13 mode cycle. We could propose the detail emission data of an automotive heavy-duty diesel engine and the characteristics of the conversion efficiency of the DOC under the D-13 mode. It was found that the mean conversion efficiencies of CO and THC were 49.7% and 61% under the D-13 mode test, respectively.