• Title, Summary, Keyword: Selective Catalytic Reduction (SCR)

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Ammonia Flow Control for NOx Reduction in SCR(Selective Catalytic Reduction) System of Refuse Incineration Plant (소각로의 Nox제어용 SCR시스템의 암모니아 공급량 제어)

  • 김인규;여태경;김상봉
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.30-34
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    • 1997
  • This paper Describe a modelling method for SCR(selective Catalytic reduction) system in refuse incineration plant. We consider the SCR system as a single input single output system. For modelling the SCR system, an auto regressive exogeneous(ARX) modelling method is used. In this case, we should design the white noise input for modelling and put it on the system as an input (.NH/sap2/.), and taken an outlet NOx as an output. From these two relations, we design the ARX model with 45 second delay time and transform to discrete system with 0.5 sampling time. Using the obtained SCR model, we simulate the SCR system to reduce the outlet NOx content by a conventional PID control method.

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Trend of Nitrogen Oxide Reduction Technologies in Cement Industry (시멘트 산업에서의 질소산화물 저감 기술 동향)

  • Seo, JunHyung;Kim, YoungJin;Cho, KyeHong;Cho, JinSang;Han, KyungHo;Yoon, DoYoung
    • Resources Recycling
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    • v.29 no.6
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    • pp.114-124
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    • 2020
  • In the cement industry, NOx emission is recognized as an important problem, and NOx reduction technologies can be divided into process change, staged combustion, low NOx burner, selective non-catalytic reduction and selective catalytic reduction method. The operation of the selective non-catalytic reduction method, which is the most used in the cement industry, is expected to make it difficult to meet the emission standards to be strengthened in the future, and it is necessary to improve equipment such as SCR and secure technologies. Recently, we are developing technologies for simultaneous application of SNCR and SCR, dust and denitrification filter technology, and removal technology using NO oxidation.

A development of reactor design software for De-NOx system using the selective catalytic reduction method (선택적 촉매 환원법을 이용한 De-NOx 시스템의 반응로 설계 전산프로그램 개발)

  • 정경열;오상훈;동은석;이수태;류길수
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • pp.187-191
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    • 2002
  • The exhaust gas from electric power stations, incinerators and industrial boilers contains considerable amount of harmful nitric oxide which causes air pollution. Selective catalytic reduction system with ammonia as a reductant(NH$_{3}$ SCR) have been applied to remove NOx since 1970. it is widely accepted that the NH$_{3}$ SCR process is the best method for the removal of NOx. In this paper the design of SCR reactor based on the NOx displacement is considered and the design program of SCR reactor is developed. The newly developed design program for de-NOx system maybe used in practice.

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Optimization for Flow Uniformity on the Selective Catalytic Reduction (SCR) System of a Steam Supply Boiler (열병합 보일러 SCR 장치의 유동 균일화를 위한 최적화 연구)

  • Park, Young-Bin;Jang, Choon-Man
    • Proceedings of the SAREK Conference
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    • pp.415-420
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    • 2009
  • Selective Catalytic Reduction(SCR) has been used for the reduction of $NO_x$ in a steam supply boiler. Recently, the reduction of $NO_x$ becomes an important research field because of its negative effect on an environment. Shape optimization of circular poles installed in the chamber, which is located in upstream of a SCR, has been performed using response surface method and three-dimensional Navier-Stokes analysis to enhance gas flow uniformity. Three design parameters, diameter, arranging angle and stretching ratio of circular poles, are considered in the present study. Throughout the shape optimization of a circular pole, gas flow uniformity is successfully increased by decreasing local recirculation flow in a square duct chamber. Recirculation flow observed in the corner of the square duct can be reduced by proper installation of a guide vane or a blunt body. Detailed flow characteristics are also analyzed and discussed.

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Selective Catalytic Reduction of NO on Manganese Sulfates (망간황화물을 이용한 NO의 선택적 촉매 환원)

  • Jeong, Soon Kwan;Park, Tae Sung;Hong, Sung Chang
    • Korean Chemical Engineering Research
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    • v.46 no.3
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    • pp.473-478
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    • 2008
  • In this experimental, selective catalytic reduction (SCR) of NO with NH3 over manganese sulfates and manganese sulfates was investigated with catalytic activity, kinetics, temperature programmed reduction (TPR) and TGA. Manganese oxides showed high catalytic activity for SCR at temperature below $200^{\circ}C$. In case of manganese sulfates, the temperature at which SCR of nitric oxide appears shifted to high temperature with sulfation degree, and the maximum catalytic efficiency decreased. The temperature of the onset of reduction for manganese oxides and manganese sulfates is about $160^{\circ}C$ and over $280^{\circ}C$, respectively. We suggest that the onset of reduction in TPR correlates with the onset of SCR activity. Because the pre-exponential factor of manganese sulfates is lower as 1/1000 times than that of other catalysts, catalytic activity of manganese sulfates for NO showed low. The reduction temperature of natural manganese ore which consists of various metal oxides showed lower than that of pure manganese oxides.

Numerical Analysis for the Flow Uniformity in the LP-SCR Reactor (LP SCR 반응기 내 유동 균일도 개선을 위한 해석적 연구)

  • Um, Hyung Sik;Kim, Gun Ho;Kim, Dae Hee;Kim, Kyu Jong;Kim, Jung Rae
    • 한국연소학회:학술대회논문집
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    • pp.61-63
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    • 2015
  • In the low pressure selective catalytic reduction (LP SCR) system, the uniformity of both ammonia concentration and exhaust gas flow at the SCR catalyst layer are important design factor for the efficient SCR-deNOx performance. According to the shape of the guide vane and static mixer, numerical simulations were conducted to analyze flow patterns and finally to find out the appropriate alternative for uniform flow at the front of catalyst in the real scale LP SCR reactor. The variations of gas velocity and ammonia concentration were quantitatively evaluated. Based on the present results, the shape was devised to satisfy the design criteria.

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Control of SCR System for NOx Reduction in a Refuse Incineration Plant Using Repetitive Control Method (반복제어법을 이용한 소각장 NOx 저감용 SCR 시스템의 제어)

  • 김인규;여태경;김환성;김상봉
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.11
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    • pp.2762-2770
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    • 2000
  • The refuse incineration plant has an important role in saving the combustion energy for local heating system. But harmful combustion gas(NOx etc.) leads to some serious environmental problem. To reduce the gas, a SCR(Selective Catalytic Reduction)system is installed and it is controlled by adjusting the flow of ammonia gas(NH3) . In this paper, we apply a repetitive control method to reduce NOx by adjusting the flow of ammonia gas for SCR system in a refuse incineration plant which is located in Haeundae, Pusan, Firstly, we analyze the inlet NOx period by FFt method, and verify its periodic variations. Secondly, we design a repetitive control system by using state space model method. Lastly, the effectiveness of repetitive control system is shown by comparing to a conventional PID control in simulation and experimental results.

Performance Prediction of SCR-DeNOx System for Reduction of Diesel Engine NOx Emission (디젤엔진의 NOx 저감을 위한 SCR-DeNOx 후처리 시스템 성능 예측)

  • 김만영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.71-76
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    • 2003
  • A numerical simulation of selective catalytic reduction (SCR) for NO with $NH_3$ is conducted over the $V_2O_5/TiO_2$ and $WO_3-V_2O_5/TiO_2$ catalysts. The governing $NH_3$ and NO transport equations are considered by using the time-dependent FCT (Flux-Corrected Transport) algorithm. After a validating simulation for $NH_3$ step feed and shut-off experiments is analyzed, transient behavior of $NH_3$ and NO concentration in a SCR catalyst is investigated by changing such parameters as inflow $NH_3$ concentration, temperature of the catalyst, and $NH_3$/NOx ratios.

Characteristics of Low Temperature De-NOx Process with Non-thermal Plasma and NH3 Selective Catalytic Reduction (II) (저온 플라즈마 및 암모니아 선택적 환원공정을 활용한 저온 탈질공정의 특성(II))

  • Lee, Jae-Ok;Song, Young-Hoon
    • Applied Chemistry for Engineering
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    • v.17 no.4
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    • pp.414-419
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    • 2006
  • Effects of water vapor, hydrocarbons, and CO, which are inevitably included in exhaust gases of combustion, on a combined $De-NO_{x}$ process of non-thermal plasma and $NH_{3}$ SCR (Selective Catalytic Reduction) have been investigated. Test results showed that fast SCR reaction enhanced $De-NO_{x}$ rate under the low temperature conditions, $150{\sim}200^{\circ}C$ The present test, however, showed that the role of the fast SCR reaction can be significantly suppressed by addition of hydrocarbons in a non-thermal plasma reactor. Detailed investigation verified that such suppressed role of the fast SCR reaction could be caused by the $NO_{2}/NO_{x}$ ratio modified by aldehydes produced from hydrocarbons in a non-thermal plasma reactor. In addition, the present study was confirmed that the effects of water vapor and CO were not noticeable compared with the hydrocarbon effects.

Reduction of Nitrogen Oxides with Diesel Oil In Pilot Scale SCR(Selective Catalytic Reduction) Process (파일럿규모의 선택적촉매환원장치에서 디젤유를 이용한 질소산화물 제거)

  • Lee, In-Young;Yoo, Kyong-Ok
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.11
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    • pp.1977-1983
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    • 2000
  • SCR(selective catalytic reduction) pilot plant for reduction of the nitrogen oxides using diesel oil as a reductant was installed at the NG(natural gas) fired combined cycle and the activity of Pt(0.3%)/Zeolite catalyst was studied in real flue gas condition according to the amount of reductant. reaction temperature and space velocity. NOx conversion gradually increased with increasing the diesel oil concentration up to C/N ratio 5.5(C/N ratio: the ratio of the number of carbon atom to the number of NOx molecules included in the flue gas). Increasing the reaction temperature. NOx conversion increased and reached a maximum conversion of 50% at $190^{\circ}C$. NOx conversion did not changed with increasing the space velocity up to 18,500/hr and then gradually decreased. These results reveal the potential for diesel oil as a reductant for de-NOx SCR process.

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