• Title/Summary/Keyword: Selective reduction

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A Study on Characteristic of NO Reduction by High Level O2Gas in Selective Non-Catalystic Reaction (High Level O2배가스중 NO 저감에 대한 선택적비촉매환원 반응특성에 관한 연구)

  • 이강우;정종현;오광중
    • Journal of Environmental Science International
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    • v.11 no.6
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    • pp.577-582
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    • 2002
  • Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increased with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850$\^{C}$ of optimal condition.

Selective Reduction of Carbonyl Compounds with B-Alkoxydiisopinocampheylborane

  • 차진순;권오운;김종미
    • Bulletin of the Korean Chemical Society
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    • v.17 no.8
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    • pp.725-729
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    • 1996
  • Reaction of carbonyl compounds with B-alkoxydiisopinocampheylborane (Ipc2BOR, R=H, Et, i-Pr, t-Bu) was investigated in detail in order to establish their usefulness as selective reducing agents. The reagents were extremely mild and reduced only aldehydes effectively under mild conditions. The reagents also reduced α,β-unsaturated aldehydes to the corresponding allylic alcohols without any detectable 1,4-reduction. Furthermore, aldehydes can be reduced in the presence of epoxides and acid chlorides. Consequently, the selective reduction of aldehyde groups in the presence of keto and all other functional groups has been realized with these reagents.

Selective Reduction of Oximes to N-Monosubstituted Hydroxylamines with Lithium Borohydride

  • Cho, Byung-Tae;Seong, See-Yearl
    • Bulletin of the Korean Chemical Society
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    • v.9 no.5
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    • pp.322-324
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    • 1988
  • Selective reduction of aldoximes and ketoximes with lithium borohydride in tetrahydrofuran was investigated. Thus, aldoximes and cyclic ketoximes such as hexanaldoxime, heptanaldoxime, cyclopentanone oxime and cyclohexanone oxime were reduced smoothly to the corresponding N-monosubstituted hydroxylamines at room temperature in 65-93% yield. The reduction of alicyclic ketoxime was very slow, requiring somewhat high reaction temperature ($65^{\circ}C$) for the complete reduction to give the hydroxnylamines. The reduction of aromatic oximes such as benzaldoxime and acetophenone oxime was very sluggish, giving a mixture of the corresponding hydroxylamines and amines at $65^{\circ}C$.

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.

Thirty Six Years of Research on the Selective Reduction and Hydroboration

  • Cha, Jin-Soon
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1808-1846
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    • 2011
  • From 1975 to 2011, for thirty six years, the author and his collaborators have developed a variety of reducing and hydroborating agents, and applied them to organic synthesis, which involves the 1,2-reduction of ${\alpha}$,${\beta}$-unsaturated carbonyl compounds, stereoselective reduction of cycloalkanones, regioselective ring-opening of epoxides, partial reduction of carboxylic acid derivatives to aldehydes, regioselective addition to carbon-carbon multiple bonds, etc. by utilizing metal hydrides and the newly-devised the Meerwein-Ponndorf-Verley (MPV) type reagents. Such developments provide a new synthetic methodology making possible valuable selective reductions and hydroborations, not practical previously.

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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    • 2009.06a
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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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