• 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.

• 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.

• 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.

• 대한안전경영과학회지
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• 제21권1호
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• pp.17-23
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• 2019

The diesel engine generate many pollutants such as PM(Particulate matter) and NOx(Nitrogen oxide). So the SCR(Selective catalytic reduction) must be required to meet the emission standard. The SCR catalyst market is growing rapidly, and the automobile markets using alternative energy sources are growing rapidly. This study deals with optimization of the calcination process the manufacturing process of SCR catalyst to be competitive. The calcination process is a bottleneck and it is required to optimize productivity and accept to be safety, But we cannot trade off anything in terms of safety. We applied DOE(Design of experiments) among many research methods performed in various fields. In order to achieve quality and productivity optimization. The dependent variables in the DOE were selected as NO Conversion(%). The independent variables were selected as the calcination temperature, soaking time and fan speed RPM. the CCD(Central composite designs) constructs response surface using the data onto experience and finds optimum levels within the fitted response surfaces. Our tests are our stability guarantee and efficient together with operation.

• 도시과학
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• 제11권1호
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• pp.29-35
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• 2022

Waste to Energy Plant were recognized as hateful facilities, and there were many conflicts in the location due to social problems such as the NIMBY phenomenon due to problems such as damage to property in the surrounding area, odor, and image loss. Problems such as air pollution and odor are solved by the development of advanced prevention facilities such as electric dust collectors, wet cleaning systems, semi-dry reaction towers, bag filters, and catalyst towers (SCR: Selective Catalytic Reduction), and air recycling facilities in waste storage tanks. However, it is being avoided because of the perception that it is an incinerator. To resolve these conflicts, the government installs and operates resident convenience facilities to compensate residents near resource recovery facilities, provides green space and improves the environment, and supports heating expenses in accordance with the 「Waste Treatment Facility Support Act」. The purpose of this study is to derive implications through the analysis of domestic and overseas case studies for resident convenience facilities and environment improvement for the promotion of local communities in resource recovery facilities and use them as basic data for community promotion and environmental improvement when installing resource recovery facilities in the future.

• 대한환경공학회지
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• 제22권4호
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• pp.609-617
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• 2000

본 연구에서는 소각로용 SCR(Selective Catalytic Reduction) 촉매개발의 일환으로, 소각로 배기가스 중에 다량 함유되어 있는 염화수소 (HCl) 기체가 촉매활성에 미치는 영향에 관하여 고찰하였다. 연구에 사용된 촉매는 상용 $V_2O_5-WO_3/TiO_2$ 촉매와 구리이온이 교환된 모더나이트형 제올라이트, CuHM 촉매로 실험은 수분의 유무에 따라 건조가스 조건과 습윤가스 조건으로 나누어 수행하였다. 건조가스 조건에서는 염화수소농도가 증가함에 따라 CuHM 촉매의 NO 제거활성이 가역적으로 증가하는 반면 $V_2O_5-WO_3/TiO_2$ 촉매는 비가역적으로 저하되는 상반되는 결과를 보였다. 그리고 수분이 포함된 습윤가스 조건에서는 CuHM와 $V_2O_5-WO_3/TiO_2$ 촉매 모두 비가역적으로 활성이 감소됨이 관찰되었으나, 상대적으로 CuHM이 보다 안정적인 활성을 나타내었다. 이러한 활성변화는 $NH_3$ TPD(Temperature Programmed Desorption) 탈착곡선의 증가, 감소로부터 HCl에 따른 일시적인 산량 증가 또는 영구적인 산점의 변화와 관계됨을 알 수 있었다. 그리고 BET 및 ICP 분석을 통하여 염화수소기체에 의한 촉매의 표면적과 $Cu^{{+}{+}}$ 및 $V_2O_5$ 함유량의 변화를 관찰하였다. 이상의 연구결과로부터 HCl과 같은 산가스를 함유하고 있는 배기가스 중의 질소산화물을 제거할 경우 CuHM 촉매에 대한 선택적 촉매 환원공정의 적용 가능성을 확인할 수 있었다.

• 해양환경안전학회지
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• 제28권7호
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• pp.1209-1215
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• 2022

선택적 촉매 환원법(SCR)은 질소산화물(NO_x)을 저감하는 매우 효율적인 방법으로 알려져 있으며 발생된 질소산화물(NO_x)을 질소(N₂)와 수증기(H₂O)로 환원시키는데 촉매 작용을 한다. 질소산화물(NO_x) 저감 성능을 결정하는 요소 중 하나인 촉매는 셀 밀도가 증가하면 촉매효율이 증가하는 것으로 알려져 있다. 본 연구에서는 실습선 세계로호에 설치되어 있는 발전 기관의 배기가스 조건을 모사한 실험장치를 통하여 100CPSI(60Cell)촉매의 부하에 따른 질소산화물(NO_x) 저감 성능을 확인하고 세계로호에 설치되어 있는 25.8CPSI(30Cell) 촉매의 기존 연구 자료와의 비교를 통해, 셀 밀도가 질소산화물(NO_x)의 저감에 미치는 영향에 대하여 고찰하였다. 실험용 촉매는 셀 밀도만 변화를 주었고 형태는 벌집형(honeycomb), 조성물질은 V₂O₅-WO₃-TiO₂를 동일하게 사용하여 제작하였다. 실험결과 100CPSI(60Cell) 촉매의 질소산화물(NO_x) 농도 저감율은 평균적으로 88.5%이며 IMO specific NOx 배출량은 0.99g/kwh로 IMO Tier III NOx 배출기준을 만족하였다. 25.8CPSI(30Cell) 촉매의 경우, 질소산화물(NO_x) 농도 저감율은 78%, IMO specific NOx 배출량은 2.00g/kwh 이었다 두 촉매의 NOx 농도 저감율과 IMO specific NOx 배출량을 비교하였을 때, 100CPSI(60Cell)촉매가 25.8CPSI(30Cell) 촉매보다, NOx 농도 저감율은 10.5% 높고 IMO specific NOx 배출량은 약 2배 적은 것을 확인하였다. 따라서 촉매의 셀 밀도를 높임으로써 효율적인 탈질효과를 기대할 수 있으며 향후 실선 테스트를 통하여 검증한다면 촉매의 부피 저감을 통한 제작 비용을 줄이고 협소한 선박 기관실을 효율적으로 사용하기 위한 실용적인 자료로서 기대된다.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.128-136
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• 2007

It is well known that two representative methods satisfy EURO-IV regulation from EURO-III. The first method is to achieve the regulation through the reduction of NOx in an engine by utilizing relatively high EGR rate and the elimination of subsequently increased PM by DPF. However, it results in the deterioration of fuel economy due to relatively high EGR rate. The second is to use the high combustion strategy to reduce PM emission by high oxidation rate and trap the high NOx emissions with DeNOx catalysts such as Urea-SCR. While it has good fuel economy relative to the first method mentioned above, its infrastructure is demanded. In this paper, the number distribution of nano PM has been evaluated by Electrical Low Pressure Impactor(ELPI) and CPC in case of Urea-SCR system in second method. From the results, the particle number was increased slightly in proportion to the amount of urea injection on Fine Particle Region, whether AOC is used or not. Especially, in case of different urea injection pressure, the trends of increasing was distinguished from low and high injection pressure. As low injection pressure, the particle number was increased largely in accordance with the amount of injected urea solution on Fine Particle Region. But Nano Particle Region was not. The other side, in case of high pressure, increasing rate of particle number was larger than low pressure injection on Nano Particle Region. From the results, the reason of particle number increase due to urea injection is supposed that new products are composited from HCNO, sulfate, NH3 on urea decomposition process.

• 대한기계학회논문집B
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• 제39권2호
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• pp.177-182
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• 2015

디젤 엔진과 산업용 보일러에서의 질소산화물(NOX) 배출은 환경오염을 유발시키는 주요물질 중의 하나이다. 이러한 질소산화물 발생을 저감시키기 위한 방법으로 후처리 기술 중의 하나인 우레아 선택적 촉매 환원(Urea-SCR)기술이 널리 사용되고 있다. 본 연구에서는 선박용 디젤엔진의 배기가스 조건을 모사한 실험실 스케일의 실험장치를 통해 우레아 수용액의 열분해 특성에 대해 고찰하였다. 40 wt. %의 우레아 농도를 가진 우레아 수용액을 사용하였고, 모사가스의 온도와 유속변화, 우레아 수용액의 유량에 따른 총 전환율 뿐만 아니라 암모니아($NH_3$)와 이소시안산(HNCO)의 전환율 차이를 알아보았다. $210^{\circ}C$와 $250^{\circ}C$ 모사가스 온도에서 체류시간에 따라 암모니아의 전환율이 이소시안산의 전환율보다 높게 나타남을 확인하였다.

• 한국자동차공학회논문집
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• 제20권4호
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• pp.125-132
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• 2012

Urea-SCR system, which converts nitrogen oxides to nitrogen and water in the presence of a reducing agent, usually AdBlue urea solution, is known as one of the powerful NOx reduction systems for mobile as well as stationary applications. For its consistent and reliable operation in mobile applications, such various problems as transient injection, ammonia slip, and freezing in cold weather have to be resolved. In this work, therefore, numerical study on three-dimensional unsteady heating problems were analyzed to understand the melting and heat transfer characteristics such as urea liquid volume fraction, temperature profiles and generated natural convection behavior in urea solution by using the commercial software Fluent 6.3. After validating by comparing numerical and experimental data with pure gallium melting phenomena, numerical experiment for urea melting is conducted with three different coolant heating models named CH1, 2, and 3, respectively. Finally, it can be found that the CH3 model, in which more coolant is concentrated on the lower part of the urea tank, has relatively better melting capability than others in terms of urea quantity of $1{\ell}$ for start-up schedule.