• 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 $(0.4{\sim}6.5){\times}10^5\;h^{-1}$.

• 공업화학
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• 제19권4호
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• pp.432-438
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• 2008

Ru/C 촉매를 이용한 p-toluidine (TLD) 선택적 수소화 반응의 특성을 파악하기 위하여 반응 온도, 수소 압력, 촉매량, 반응용매 및 알카리 첨가제와 같은 공정변수들을 변화시켜가면서 반응속도와 생성물 분포에 미치는 영향을 조사하였다. TLD 수소화 반응에서 4-methylcyclohexylamine (MCHA)이 주된 생성물로 얻어졌으며 부반응물로는 bis(4-methyl cyclohexyl) amine (BMCHA)이 주로 생성되었다. MCHA는 온도와 압력의 증가에 따라 감소하였지만, 촉매량에 따라서는 증가함을 나타내었다. 용매의 변화에서는 isopropanol (IPA)에서 가장 좋은 선택도를 나타내었다. 이로부터 TLD 선택적 수소화에 대한 반응 기구를 제시하였다. 알카리염의 첨가는 BMCHA의 생성률을 낮게 하여 MCHA로의 선택도를 증가시켰으며 반응속도 또한 증가시켜주는 효과를 나타내었다.

• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.455-463
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• 2021

In this study, CeO₂ support is synthesized from cerium hydroxy carbonate prepared using precipitation/digestion method using KOH and K₂CO₃ as the precipitants. The Cu was impregnated to CeO₂ support with the different loading (Cu loading=10-40 wt. %). The prepared Cu/CeO₂ catalysts were applied to a single stage water gas shift (WGS) reaction. Among the prepared catalysts, the 20Cu/CeO₂ catalyst contained 20 wt.% of Cu showed the highest CO conversion (Xco=68% at 400℃). This result was mainly due to a large amount of active sites. In addition, the activity of the 20 Cu/CeO₂ catalyst was maintained without being deactivated for 100 hours because of the strong interaction between Cu and CeO₂. Therefore, it was confirmed that 20 Cu/CeO₂ is a suitable catalyst for a single WGS reaction.

• 청정기술
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• 제29권4호
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• pp.321-326
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• 2023

최근 탄소중립과 관련하여 연소 시 이산화탄소 배출이 없어 청정한 수소에너지에 대한 관심이 증가하고 있다. 이에 따라 수소 생산에 관련된 연구가 계속되고 있으며 본 연구에서는 폐기물을 처리함과 동시에 고순도 수소를 생산하기 위해 폐기물 유래 합성가스를 수성가스전이반응에 적용하였다. 마그네슘을 세륨과 함께 지지체로 사용하여 고온수성가스전이(HT-WGS)반응에서 촉매의 활성을 향상시키고자 하였다. HT-WGS 반응의 활성물질로 구리를 사용해 Cu-CeO₂-MgO 촉매를 제조하였으며, 제조방법에 따른 촉매활성 연구를 진행하였다. HT-WGS 반응 결과 함침법으로 제조된 Cu-CeO₂-MgO 촉매가 가장 높은 활성을 보였으며, 이는 가장 높은 산소 저장능과 많은 활성 Cu 종을 가지는 특성에 기인한 결과이다.

• 한국지반환경공학회 논문집
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• 제17권10호
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• pp.5-11
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• 2016

본 연구에서는 포름알데히드를 상온산화시켜 제거하는 $Pt/TiO_2$ 촉매의 상용화 인자들이 조사되었다. 활성 귀금속 함량 최적화를 위해 촉매의 백금(Pt) 담지량을 변화시켜 제조 후 성능을 평가하였으며, 그 결과 1wt% 함량이 가장 이상적인 함량임을 확인하였다. 또한 활성금속인 Pt를 환원하여 제조한 환원 촉매가 상온에서 우수한 포름알데히드 산화 능력을 나타내었다. 이를 통해 활성금속의 산화가에 따라 성능이 변화될 수 있으며, 백금의 경우 metallic Pt($Pt^0$)로 존재할수록 포름알데히드 상온산화 성능이 증진될 수 있음을 확인하였다. 촉매의 운전인자를 도출하기 위한 공간속도 영향 평가 결과 공간속도가 낮을수록 촉매량 증가에 의해 포름알데히드 전환율이 증진되는 결과를 나타내었다. 또한 공기 내 반드시 존재하는 물질인 수분의 공기 내 공존 시 영향 평가를 실시하였으며, 그 결과 수분이 공존할 때 포름알데히드 산화반응이 수분이 존재하지 않은 조건에서의 활성보다 증진되었다. 상기 결과들을 통해 어떤 추가 에너지원 없이도 포름알데히드를 제거 할 수 있는 상온산화 촉매 상용화를 위한 핵심인자들을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제18권7호
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• pp.703-706
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• 1997

Response surface method was applied to the predicting optimum conditions of benzene synthesis for radiocarbon dating. The weight of carbon dioxide, the temperature of lithium container for producing acetylene and the activation temperature of catalyst which was used for the cyclization of acetylene to benzene were used as experimental factors. The yields of benzene synthesis were measured from twelve experiments which were carried out under various experimental conditions. The polynomial equation was obtained by using three experimental factors and yields. The validity of polynomial equation was confirmed by comparing the calculated yields with the experimental ones.

• 한국응용과학기술학회지
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• 제16권2호
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• pp.135-141
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• 1999

A synthesis of Dimer acid was studied from a tall oil fatty acid. Catalytic activity measured as reactant conversion in a autoclave reactor increase in accordance with the acidity. The optimization of process conditions were tested by an experimental design method. Optimization synthetic conditions of dimer acid and were reaction of tall oil fatty acid during 2 hour at $250^{\circ}C$, used of 7.3 wt% active clay and $1.2{\sim}1.4wt%$ water, and found reation pressure $8{\sim}9Kg/cm^2$. The maximum conversion rate was researched $74{\sim}76%$.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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• pp.99-105
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• 2001

For the design of selective catalytic reactors of NOx by $NH_3$, engineering approach can be performed to determine the reactor shape, mixing device and $NH_3$ injection system. This study shows the optimization of guide vanes to improve the flow pattern near the catalyst layer of SCR in a untility boiler. By varying their spacings and shapes, flow performance of guide vanes was analyzed to achieve an uniform velocity distribution which increases the NOx convesion efficiency, and a flow direction normal to the layer which minimises the erosion by the dust in the flue gas. Including these results, experimental and numerical studies for the SCR design were discussed.

• 국제초고층학회논문집
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• 제6권4호
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• pp.307-313
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• 2017

This paper outlines the processes and strategies studied and selected by the team during the design stages of the project for the incorporation of BIPV into the tower's façade. The goal was to create a system that helps reduce internal heating and cooling loads while collecting energy through photovoltaic panels located throughout the building. The process used to develop this façade system can be broken down into three stages. 1. Concept: BIPV as design catalyst for a high-rise building. 2. Optimization: Balancing BIPV and Human comfort. 3. Integration: Incorporating BIPV into a custom curtain wall design. The FKI Project clearly illustrates the evolution building enclosures from simple wall systems to high performance integrated architectural and engineering design solutions. This design process and execution of this project represent the design philosophy of our firm.

• Advances in nano research
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• 제12권4호
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• pp.387-403
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• 2022

Silica nanoparticles, which have a broad range of sizes and specific surface features, have been used in many industrial applications. This study was conducted to synthesize monodispersed silica nanoparticles directly from tetraethyl orthosilicate (TEOS) with an alkaline catalyst (NH₃) based on the sol-gel process and the Stöber method. A central composite design (CCD) is used to build a second-order (quadratic) model for the response variables without requiring a complete three-level factorial experiment. The process was then optimized to achieve the minimum particle size with the lowest concentration of TEOS. Dynamic light scattering and scanning electron microscopy were used to analyze the size, dispersity, and morphology of the synthesized nanoparticles. After optimization, a confirmation test was carried out to evaluate the confidence level of the software prediction. The results revealed that the predicted optimization is consistent with experimental procedures, and the model is significant at the 95% confidence level.