• Title/Summary/Keyword: manganese oxide catalyst

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A Study on Characterization for Low Temperature SCR Reaction by $Mn/TiO_2$ Catalysts with Using a Various Commercial $TiO_2$ Support (다양한 상용 $TiO_2$ 담체를 이용한 $Mn/TiO_2$ 촉매의 저온 SCR 반응 특성 연구)

  • Kwon, Dong Wook;Choi, Hyun Jin;Park, Kwang Hee;Hong, Sung Chang
    • Applied Chemistry for Engineering
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    • v.23 no.2
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    • pp.190-194
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    • 2012
  • 10 wt% Mn supported on various commercial $TiO_2$ catalysts were prepared by wet-impregnation method for the low temperature selective catalytic reduction (SCR) of NO with $NH_3$. A combination of various physico-chemical techniques such as BET, XRD, XPS and TPR were used to characterize these catalysts. MnOx surface densities on MnOx/$TiO_2$ catalyst were related to surface area. As MnOx surface density lowered with high dispersion, the SCR activity for low temperature was increased and the reduction temperature ($MnO_2$ ${\rightarrow}$ $Mn_2O_3$) of surface MnOx was lower. For a high SCR, MnOx could be supported on a high surface area of $TiO_2$ and should be existed a high dispersion of non-crystalline species.

Effect of Ce Addition on Catalytic Activity of Cu/Mn Catalysts for Water Gas Shift Reaction (수성가스전이반응(Water Gas Shift Reaction)을 위한 Ce 첨가에 따른 Cu/Mn 촉매의 활성 연구)

  • PARK, JI HYE;IM, HYO BEEN;HWANG, RA HYUN;BAEK, JEONG HUN;KOO, KEE YOUNG;YI, KWANG BOK
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.1
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    • pp.1-8
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    • 2017
  • Cu/Mn/Ce catalysts for water gas shift (WGS) reaction were synthesized by urea-nitrate combustion method with the fixed molar ratio of Cu/Mn as 1:4 and 1:1 with the doping concentration of Ce from 0.3 to 0.8 mol%. The prepared catalysts were characterized with SEM, BET, XRD, XPS, $H_2$-TPR, $CO_2$ TPD, $N_2O$ chemisorption analysis. The catalytic activity tests were carried out at a GHSV of $28,000h^{-1}$ and a temperature range of 200 to $400^{\circ}C$. The Cu/Mn(CM) catalysts formed Cu-Mn mixed oxide of spinel structure ($Cu_{1.5}Mn_{1.5}O_4$) and manganese oxides ($MnO_x$). However, when a small amount of Ce was doped, the growth of $Cu_{1.5}Mn_{1.5}O_4$ was inhibited and the degree of Cu dispersion were increased. Also, the doping of Ce on the CM catalyst reduced the reduction temperature and the base site to induce the active site of the catalyst to be exposed on the catalyst surface. From the XPS analysis, it was confirmed that maintaining the oxidation state of Cu appropriately was a main factor in the WGS reaction. Consequently, Ce as support and dopant in the water gas shift reaction catalysts exhibited the enhanced catalytic activities on CM catalysts. We found that proper amount of Ce by preparing catalysts with different Cu/Mn ratios.

Selective Catalytic Reduction of NO by H2 over Pt-MnOx/ZrO2-SiO2 Catalyst (Pt-MnOx/ZrO2-SiO2 촉매에서 수소에 의한 일산화질소의 선택적 촉매 환원반응)

  • Kim, Juyoung;Ha, Kwang;Seo, Gon
    • Korean Chemical Engineering Research
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    • v.52 no.4
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    • pp.443-450
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    • 2014
  • Selective catalytic reduction of nitrogen monoxide by hydrogen ($H_2$-SCR of NO) over platinum catalysts impregnated on zirconia-incorporated silica ($ZrO_2-SiO_2$) and manganese oxide ($MnO_x$) was investigated. $Pt-MnO_x$ catalyst showed low conversions and low yields of $N_2O$ and $NO_2$ at $100{\sim}350^{\circ}C$. On the other hand, NO conversions over $Pt/ZrO_2-SiO_2$ were very high, but $N_2O$ was predominantly produced at $100-150^{\circ}C$ and the yield of $NO_2$ increased with temperature at $200-300^{\circ}C$, resulting in poor $N_2$ yields. $Pt-MnO_x/ZrO_2-SiO_2$ exhibited a small enhancement in $N_2$ yield at $100-150^{\circ}C$ due to the synergy of $MnO_x$ and $ZrO_2-SiO_2$. The surface composition and oxidation state of the catalyst components and the acidity of the catalysts were examined. IR spectra of the adsorption of NO and their subsequent reactions with hydrogen on these catalysts were also recorded. The variations of conversion and product yield according to the catalyst components in the $H_2$-SCR of NO were discussed in relation to their catalytic roles.

A Study on Catalytic Pyrolysis of Polypropylene with Mn/sand (Mn/sand 촉매를 활용한 폴리프로필렌 촉매 열분해 연구)

  • Soo Hyun Kim;Seung Hun Baek;Roosse Lee;Sang Jun Park;Jung Min Sohn
    • Clean Technology
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    • v.29 no.3
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    • pp.185-192
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    • 2023
  • This study was conducted to obtain basic process simulation data before conducting pyrolysis experiments for the development of a thermochemical conversion system by recirculation of heat carrier and gases thereby. In this study, polypropylene (PP) was used as a pyrolysis sample material as an alternative to waste plastics, and fluid sand was used as a heat transfer medium in the system. Manganese (Mn) was chosen as the catalyst for the pyrolysis experiment, and the catalyst pyrolysis was performed by impregnating it in the sand. The basic properties of PP were analyzed using a thermogravimetric analyzer (TGA), and liquid oil was generated through catalytic pyrolysis under a nitrogen atmosphere at 600℃. The carbon number distribution of the generated liquid oil was confirmed by GC/MS analysis. In this study, the effects of the presence and the amount of Mn loading on the yield of liquid oil and the distribution of hydrocarbons in the oil were investigated. When Mn/sand was used, the residue decreased and the oil yield increased compared to pyrolysis using sand alone. In addition, as the Mn loading increased, the ratio of C6~C9 range gasoline in the liquid oil gradually increased, and the distribution of diesel and heavy oil with more carbon atoms than C10 in the oil decreased. In conclusion, it was found that using Mn as a catalyst and changing the amount of Mn could increase the yield of liquid oil and increase the gasoline ratio in the product.

Study on 1,200 N-class bipropellant rocket engine using decomposed $H_2O_2$ and kerosene (분해된 과산화수소와 케로신을 이용한 1,200 N 급 이원추진제 로켓 엔진의 연구)

  • Jo, Sung-Kwon;An, Sung-Yong;Kim, Jong-Hak;Yoon, Ho-Sung;Kwon, Se-Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.6
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    • pp.69-78
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    • 2010
  • As part of preliminary study for development of 1,200 N-class bipropellant rocket engine with the concentrated hydrogen peroxide, bipropellant engine elements were designed and experimentally tested. The catalysts of $MnO_2$ and $MnO_2$ added Pb as an additive were compared to achieve high decomposition performance and the catalytic reactor with $MnO_2$ added Pb was designed and its decomposition efficiency of 97.2% was achieved. The autoignition tests of kerosene by decomposed hydrogen peroxide were carried out under various equivalence ratios to ignite without additional ignition sources. Autoignition were achieved in all experimental conditions and $C^*$ efficiencies at each condition were at or above 90%. From the measured thrust results, the highest value was 830 N which is in corresponds with 1,035 N at vacuum level assuming $C^*$ efficiency equals $I_{sp}$ efficiency.

Removal of Carbon Monoxide from Anthracite Flue Gas by Catalytic Oxidation (I) (촉매반응에 의한 연탄 연소가스로부터 일산화탄소의 제거 (제1보))

  • Chung Ki Ho;Lee, Won Kook
    • Journal of the Korean Chemical Society
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    • v.20 no.5
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    • pp.431-437
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    • 1976
  • On the condition of adequate air supply, complete removal of carbon monoxide,occurred above $650^{\circ}C$. Using catalysts, the oxidation of carbon monoxide occurred at lower temperatures; on both $MnO_2 \;and\;30%\;MnO_2-70%\;CuO\;at\;250{\circ}C,\;on\;CuO\;at\;450{\circ}C,\;on\;50%\;MnO_2-50%\;CuO\;at\;200{\circ}C,\;and\;on\;70%\;MnO_2-30%\;CuO\;at\;180{\circ}C$. Manganese dioxide (p-type) showed higher activity than cupric oxide (n-type) and a catalyst consisting of 60% $MnO_2-40%$ CuO had the highest activity of all the $MnO_2$-CuO mixture. Over the range of transitional temperature, carbon monoxide removal efficiency decreased linearly with increasing inlet carbon monoxide concentration while temperature was fixed. Residence time of gases in the catalytic reactor, in the range of 0.9 to 1.8 seconds, gave no effect on carbon monoxide conversion.

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Study on 1,200 N-class bipropellant rocket engine using decomposed $H_2O_2$ and kerosene (분해된 과산화수소와 케로신을 이용한 1,200 N 급 이원추진제 로켓 엔진의 연구)

  • Jo, Sung-Kwon;An, Sung-Yong;Kim, Jong-Hak;Yoon, Ho-Sung;Kwon, Se-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.156-164
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    • 2010
  • As part of preliminary study for development of 1,200 N-class bipropellant rocket engine with the concentrated hydrogen peroxide, bipropellant engine elements were designed and experimentally tested. The catalysts of $MnO_2$ and $MnO_2$ added Pb as an addictive were compared to achieve high decomposition performance and the catalytic reactor with $MnO_2$ added Pb was designed and its decomposition efficiency of 97.2% was achieved. The autoignition tests of kerosene by decomposed hydrogen peroxide were carried out under various equivalence ratios to ignite without additional ignition sources. Autoignition were achieved in all experimental conditions and $C^*$ efficiencies at each condition were at or above 90%. From the measured thrust results, the highest value was 830 N which is in corresponds with 1,035 N at vacuum level using 94.1% theoretical $I_{sp}$.

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Decomposition of Ethylene by Using Dielectric Barrier Discharge Plasma (유전체 배리어 방전 플라즈마를 이용한 에틸렌의 분해)

  • Jang, Doo Il;Lim, Tae Hun;Lee, Sang Baek;Mok, Young Sun;Park, Hoeman
    • Applied Chemistry for Engineering
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    • v.23 no.6
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    • pp.608-613
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    • 2012
  • Dielectric barrier discharge plasma reactor was applied to the removal of ethylene from a simulated storage facility ($1.0m^3$) of fruits and vegetables. The system operated in a closed-loop mode by feeding the contaminated gas to the plasma reactor and recirculating the treated gas back to the storage facility. The experiments were carried out with parameters such as discharge power, circulation flow rate, initial ethylene concentration and treatment time. The rate of ethylene decomposition was mainly controlled by the discharge power and the treatment time. With the other conditions kept constant, the ethylene decomposition rate in the presence of the manganese oxide ozone control catalyst installed downstream from the plasma reactor was lower than that in the absence of it. The suggests that unreacted ozone from the plasma reactor accumulated in the storage facility where it additionally decomposed ethylene. On the basis of an initial ethylene concentration of 50 ppm, the energy requirement for completing the decomposition was about 60 kJ.