• Journal of the Korea Society of Computer and Information
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• v.28 no.1
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• pp.121-127
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• 2023

In this study, the design conditions and CFD analysis results are compared and reviewed in SCR that can optimally reduce nitrogen compounds. To this end, it was analyzed and compared using CFD to see if the design criteria were satisfied for the shell and tube areas of the boiler. In the SCR system, the analysis area is the gas/air heat exchanger on the shell side, and eight tubes of the gas/air heat exchanger on the tube side. Through CFD analysis, the gas velocity distribution on the primary catalyst side of the SCR system was designed to be 2.4%, and the NH3/NOx molar ratio distribution was 3.7%, which satisfied the design criteria. In addition, the uniformity of the temperature distribution was confirmed and the required condition of 260℃ or higher was satisfied. The angle of the gas entering the catalyst met the design conditions at 2.9 degrees, and the pressure loss that occurred also satisfied the design requirements. Through this CFD analysis, it was confirmed that it was designed and operated by satisfying the design conditions required for each area.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.3
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• pp.360-368
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• 2010

A SCR catalytic filter system is used for reducing $NO_x$ and soot emissions simultaneously from diesel combustors. The amount of ammonia (as a reducing agent) must be controlled with the amount of $NO_x$ to obtain an optimal $NO_x$ conversion. Hence, gas mixing between ammonia and exhaust gases is vital to ensure that the SCR catalyst is optimally used. If ammonia mass distribution is not uniform, slip potential will occur in rich concentration areas. At lean areas, on the other hand, the catalyst is not fully active. The better mixing is indicated by the higher uniformity of ammonia mass distribution which is necessary to be considered in SCR catalytic filter system. The ammonia mass distributions are depended on the flow field of fluids. In this study, the velocity field of gaseous flow is investigated to characterize the transport of ammonia in SCR catalytic filter system. The influence of different injection placements on the ammonia mass distribution is also discussed. The results show that the ammonia mass distribution is more uniform for the injector directed radially perpendicular to the main flow of inlet at the gravitational direction than that at the side wall for both laminar (Re = 640) and turbulent flows (Re = 4255). It is also found that the mixing index decreases as increasing the heating temperature in the case of ammonia injected at the side wall.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.153-158
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• 2019

The overall environmental regulations of the industry have been strengthened due to environmental pollution that occurred in modern society. Therefore, R&D of selective reduction catalyst (SCR) is needed to meet these environmental regulations. This paper carried out thermal analysis to develop the pneumatic damper valve (PDV), which is a key component of SCR system. For thermal analysis, verification of material properties was performed first. Verification was performed through the thermal properties test and the thermal tensile test of the specimen, and the results were reinforced with the material properties to enhance the reliability of the thermal analysis.The heat analysis was intended to identify thermal characteristics with PDV in total of three materials (SM400B, SS275, SB410) applied under the conditions of use of PDV, and to confirm the structural stability of the PDV.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.9
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• pp.434-440
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• 2005

This paper describes an optimized Scheme of reactive-power compensation for the low short-circuit-ratio AC system interconnected with the HVDC system. An HVDC system interconnected with tile low SCR AC system is vulnerable to the ac voltage variation, which brings about the commutation failure of the converter. This problem can be solved using optimized compensation of reactive power. In this study, a benchmark system for HVDC system interconnected with low SCR AC system is derived using PSS/E simulation. Then an optimized srheme for reactive power compensation was derived using integer programming. The feasibility of proposed scheme was analyzed through silnulations with PSS/E and PSCAD/EMTDC. The proposed scheme can compensate the reactive power accurately and minimize the number of switching for harmonic filters and shunt reactors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.816-822
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• 2008

This study presents the design modification for SCR muffler of a commercial vehicle. Its main objective is the reduction of radiated noise at SCR muffler. For this study, the research of five steps were achieved by experimental and CAE analysis. First step is the measurement of radiated noise using impact-acoustic test. Second step is the source identification using experimental modal analysis. The cause of radiated noise source is confirmed by the resonance of end plates at SCR muffler. Third step confirms the possibility of resonance avoidance using SDM analysis applied the mass control. Fourth step is the suggestion of design modification which is the change of mode shape by CAE analysis. Last step is the verification of design modification using SYSNOISE analysis. Finally, the prototype product applied the countermeasure of resonance evasion was manufactured and the reduction of radiated noise at SCR muffler was confirmed by pass-by noise test.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.68-76
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• 2008

Diesel $NO_x$ reduction by $NH_3$-SCR in conjunction with the effective oxidation precatalyst was analytically investigated. Physicochemical processes in regard to $NH_3$-SCR $NO_x$ reduction and catalytic NO-$NO_2$ conversion are formulated with detailed descriptions on the commanding reactions. A unified model is correctly validated with experimental data in terms of extents of $NO_x$ reduction by SCR and NO-$NO_2$ conversion by DOC. The present deterministic model based on the rate expressions of Langmuir-Hinshelwood reaction scheme finds a conversion extent directly. A series of numerical experiments concomitant with parametric analysis of the $NO_x$ reduction was conducted. $NO_x$ reduction is promoted in proportion to DOC volume ar lower temperatures and an opposite holds at lower space velocity and intermediate temperatures. $NO_x$ conversion is weakly correlated to the space velocity and the DOC volume at higher exhaust temperature. In DOC-SCR system, the $NO_x$ reduction efficiency depends on the $NH_3/NO_x$ ratio.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.28-35
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• 2012

This study is on SCR reactor, NOx reduction system in Marine that has been an issue nowadays. Especially design data was obtained by numerical on flow uniformity that is one of the design factor in SCR reactor. Also pressure drop on catalyst size inserted into SCR reactor was compared by experiment and numerical analysis. S/W, numerical analysis used for this study was confirmed that the result of numerical analysis used STAR-CCM+, common use CFD code, pressure drop on catalyst is not big different from the result of numerical analysis. In addition, degree of uniformity of liquid on SCR reactor was over 0.9. Whereas it was assured that degree of uniformity of liquid was changed depends on the shape of pipe at the entrance of SCR.

• Journal of ILASS-Korea
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• v.21 no.3
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• pp.130-136
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• 2016

NOx and PM are important air pollutants as vehicle management policy aspect. Medium-duty truck is the main source of the pollutants although the vehicle market share is only 3.5%. National emission portion of NOx and PM form the mobile sourece are 14% and 16% respectively. In this study it was investigated that characteristics of air pollutants emission on medium duty truck equipped with EGR and SCR system. Vehicle's test reflected driving cycle on the chassis dynamometer, and applied test cycle was WHVC(World Harmonized Vehicle Cycle) mode. The test cycle include three segments, represent urban, rural and motorway driving. Based on the test results NOx, PM, HC were less emitted form SCR vehicle than EGR vehicle. And CO was less emitted form EGR vehicle than SCR vehicle due to CO oxidation reaction on DPF surface. And most air pollutants reduced as average vehicle speed increased. Pollutants were less emitted on motorway section than urban and rural sections. But highly NOx emission on motorway section was verified according to increased EGR ratio on fast vehicle speed. HC and CO additional emission was identified as 68%, 58% respectively during SCR vehicle's cold engine start emission test. NOx additional emission was detected by 24% on SCR vehicle's condition of engine cold start while not detected on vehicle equipped with EGR. SCR vehicle's additional NOx emission was derived from low reaction temperature during engine cold start condition. medium-duty truck emission characteristics were investigated in this study and expected to used to improve air pollutants management policy of medium-duty truck equipped with SCR & EGR.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.23-24
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• 2006

The International Maritime Organization announced that the regulation of nitrogen oxide put into force for vessels constructed after 2000 from May, 2005 as agenda is satisfied on May, 2004. A honeycomb-typed Pillared Inter-Layered Clay(PILC) catalyst was developed for do-NOx SCR system in 2004. This catalyst has been applied to 9H25/33 engine that is one of the main diesel engines in Engine Machinery Division of the Hyundai Heavy Industries CO., LTD. In addition, we have tried to develop better catalysts in the aspects of easy synthetic method and performance.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.618-620
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• 2010