• Title/Summary/Keyword: $H_2$ SCR

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The effect of moisture on SCR reaction of NMO (Natural Manganese Ore) (천연망간광석 SCR 반응에서 수분의 영향)

  • Kim, Sungsu;Hong, Sungchang
    • Applied Chemistry for Engineering
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    • v.18 no.4
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    • pp.350-355
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    • 2007
  • The effect of moisture in flue gas on SCR reaction of NMO (Natural Manganese Ore) was studied. The experiments were performed over NMO with NO, $NH_3$ at independent condition or simultaneous condition. $NH_3$ can be oxidized at low temperature by the lattice oxygen in NMO catalyst. The concentration of NO and $NO_2$ by $NH_3$ oxidation with moisture is higher above $300^{\circ}C$ than that without moisture. Moisture would competitively adsorb with NO and $NH_3$ on NMO catalyst. It caused poor NOx conversion to compete against $H_2O$. Besides the NOx conversion efficiency was reduced at below $250^{\circ}C$ because of the dipped $H_2O$ competitively adsorbed $NH_3$. The reactivity of NMO varied with the calcination temperature and the optimum calcination temperature was $400^{\circ}C$ regardless $H_2O$.

The Optimum Condition Analysis of Vanadium Solvent Extraction by Alamine336 from the Synthetic Vanadium Sulfate Solution. (황산바나듐 모의용액으로부터 Alamine336에 의한 바나듐 용매추출의 최적조건 연구)

  • Ahn, Jong-Gwan;Ahn, Jae-Woo
    • Korean Journal of Metals and Materials
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    • v.46 no.12
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    • pp.823-829
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    • 2008
  • The solvent extraction process for the recovery of vanadium from leaching solution of SCR(selective catalytic reduction) spent catalyst was investigated by using Alamine336 as an extractant. The effects of experimental conditions, such as initial pH and concentration of sulfate ion, and ammonia concentration of stripping solution were studied. The extraction percentage of vanadium were increased with the increase of initial pH of leaching solution and decreased with the increase of sulfate ion. More than 99% of vanadium in leaching solution were extracted and stripped at the A/O ratio of 1.0 in 2 stages. On the basis of these results, an optimum solvent extraction process which vanadium was effectively recovered from SCR spent catalyst was proposed.

Frozen and Melting Characteristics of Urea-aqueous Solution for Urea-SCR System by Circulation of Engine Coolant (엔진 냉각수 순환에 의한 urea-SCR 시스템용 요소수의 동결 및 해동 특성)

  • Choi, B.C.;Kim, Y.K.;Kim, H.N.
    • Journal of Power System Engineering
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    • v.15 no.4
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    • pp.42-47
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    • 2011
  • The purpose of this study is to investigate the best melting condition with various winding number of a heating pipe, supplying quantity of engine coolant and coolant temperature at the inlet of the heating pipe. Also, it is to suggest getting method of an appropriate quantity of the agent for the urea-SCR system within 10 minutes. For this matter, this study identifies the temperature distribution of inside of urea-tank while it is frozen at the low temperature condition, and suggests the best melting condition of the frozen urea within 10 minutes. From the results, it was found that 2L of melted urea was obtained by the coolant flow rate of 200L/hr at $70^{\circ}C$ for 10 minutes from the start of engine operating.

A Study on NH3-SCR Vanadium-Based Catalysts according to Tungsten Content for Removing NOx Generated from Biogas Cogeneration (바이오가스 열병합 발전에서 발생하는 NOx 제거를 위한 텅스텐 함량에 따른 NH3-SCR 바나듐계 촉매 연구)

  • Jung, Min Gie;Hong, Sung Chang
    • Clean Technology
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    • v.27 no.4
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    • pp.315-324
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    • 2021
  • In this study, a vanadium catalyst study was conducted on the various characteristics of the exhaust gas in the Selective-Catalytic-Reduction (SCR) method in which nitrogen oxides emitted from cogeneration using biogas are removed by using ammonia as a reducing agent and a catalyst. V/W/TiO2, a commercial catalyst, was used as the catalyst in this study, and the effect was confirmed according to the tungsten content under various operating conditions. As a result of the NH3-SCR experiment, the denitrification performance was confirmed at 380 ~ 450 ℃ more than 95%, and durability to trace amounts of SO2 was confirmed through the SO2 durability experiment and TGA analysis. As a result of H2-TPR analysis, the higher the tungsten content, the better the redox properties. Accordingly, enhanced oxidizing properties were confirmed in the oxidation test for a trace amount of carbon monoxide emitted from the cogeneration. In NH3-DRIFTs analysis, it was confirmed that the higher the tungsten content, the higher both the Bronsted/Lewis acid sites and the better the thermal durability when tungsten is added to the catalyst. Based on the experiments under various operating conditions, it is considered that a catalyst with a high tungsten content is suitable to be applied to cogeneration using biogas.

NOx Removal of NH3-SCR Catalysts with Operating Conditions (공정조건에 따른 NH3-SCR용 촉매의 질소산화물 제거특성)

  • Park, Kwang Hee;Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5610-5614
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    • 2012
  • Performance of catalyst was studied with various operating conditions for selective catalytic reduction of $NO_x$ with $NH_3$. It is confirmed that catalysts containing Mn and Cu have a good efficiency in the usage of oxygen by the $H_2$-TPR analysis. In the case of catalyst #1, $NO_x$ conversion was decrease with the increase of reaction temperature. But in the case of catalyst #2, $NO_x$ conversion was increased and then remained constant with the increase of reaction temperature. This phenomenon is due to the difference of the $NH_3$ oxidation of both catalysts.

Selective Catalytic Reduction (SCR) of NOx with NH3 on Sb-promoted VWTi Catalysts (Sb 첨가에 따른 VWTi 촉매의 암모니아 선택적 촉매 환원(SCR)을 통한 질소산화물 저감)

  • Kim, Su Bin;Choi, Gyeong Ryun;Shin, Jung Hun;Hong, Sung Chang
    • Applied Chemistry for Engineering
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    • v.32 no.1
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    • pp.35-41
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    • 2021
  • VWTi, which is used as a commercial catalyst in NH3-SCR, exhibits excellent denitrification performance at 300 to 400 ℃, but there is a problem that efficiency decreases at low temperatures below 300 ℃. Research on catalysts containing promoter to increase low-temperature denitrification efficiency is steadily progressing. However, research on the cause of the improvement in low-temperature denitrification efficiency of the catalyst and the catalyst properties is insufficient. In this study, it was confirmed that by adding Sb to VWTi, denitrification performance was improved by more than 10% in NH3-SCR reaction below 300 ℃. At this time, the space velocity and the size of the catalyst particles were controlled to exclude the influence of external/internal diffusion. In addition, the catalytic properties according to the presence or absence of Sb were investigated by performing BET, TEM/EDS, O2-TPD, H2-TPR and DRIFTs analysis. It was judged that the addition of Sb increased the adsorbed oxygen species on the surface of the catalyst, thereby enhancing the redox properties of the catalyst at low temperature and exhibiting excellent denitrification performance.

Enhanced NH3-SCR Activity of V/TiO2 Catalyst Prepared by Various Ball Mill Method (다양한 Ball Mill Method에 의해 제조된 V/TiO2 촉매의 NH3-SCR 활성 증진연구)

  • Kim, Dong Ho;Seo, Phill Won;Hong, Sung Chang
    • Clean Technology
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    • v.23 no.1
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    • pp.64-72
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    • 2017
  • In this study, the selective catalytic reduction (SCR) for NOx removal was investigated in the temperature range of $150{\sim}400^{\circ}C$. XRD, BET and XPS analyses to determine the structural properties and valence state characteristics of the catalyst were performed. Various ball mill method were shown to a difference in activity at a low temperature below $250^{\circ}C$. Based on the catalyst with the highest denitrification efficiency, the ball mill time was the best result at 3 h. As a result of XPS analysis, the presence of the non-stoichiometric vanadium species and the increase of the number of atoms were attributed to a positive effect in the SCR reaction. it was confirmed that the correlation between the amount of lattice oxygen and the denitrification efficiency through the $O_2$ on-off experiment, and it was in a proportional relationship to each other.

NOx removal of Mn-Cu-TiO2 catalyst for the calcination and oxygen concentration conditions (소성 및 산소농도 조건에 대한 Mn-Cu-TiO2 촉매의 탈질 특성)

  • Jang, Hyun Tae;Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.900-905
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    • 2015
  • DeNOx catalysts composed of Mn, Cu and $TiO_2$ were prepared and tested for $NH_3$-SCR. The performance of each catalyst was studied for the NOx removal efficiency while changing the calcination temperature, reaction time, and oxygen concentration. The hydrogen conversion efficiency of a calcined catalyst was measured at the $H_2$-TPR system. The change in the specific surface area of catalyst according to the calcination temperature was analyzed. As a result, the proper calcination temperature was approximately $300^{\circ}C$. If the calcination temperature is increased to $500^{\circ}C$, the NOx removal efficiency of Mn and Cu constituents is largely decreased at the low temperature range. Oxygen in flue gas is an important parameter in the SCR reaction and optimal oxygen concentration is approximately 8 vol.%.

The Effect of Biodiesel Blend Fuels As Reductants on NOx Conversion Efficiency of HC_SCR (환원제로서 바이오디젤 혼합연료가 HC-SCR의 NOx 변환효율에 미치는 영향 연구)

  • Song, Hoyoung;Lee, Minho;Kim, Kiho
    • Journal of Energy Engineering
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    • v.24 no.4
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    • pp.140-145
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    • 2015
  • This study was aimed at analyzing NOx conversion characteristics in the HC-SCR with biodiesel content changes of the secondary fuel injection (BD0, BD10, BD25). Test conditions for temperature were set to $290^{\circ}C$, $320^{\circ}C$ and $350^{\circ}C$ considering the upstream temperature of a HC-SCR, distillation of the secondary injected fuels and etc. The amount of fuel injection was adjusted with a fixed space velocity of 55,000(1/h). According to the test results of distillation, the T90 was the same level about $350^{\circ}C$ on all test fuels and the amount of evaporation was reduced at lower than $350^{\circ}C$ temperature condition with increasing biodiesel content. As biodiesel content which is mixed with the secondary injected fuel is increased, NOx reduction efficiency was determined to decrease. The difference of the Nox reduction ratio in a high temperature condition($320^{\circ}C$ and $350^{\circ}C$) than the low temperature($290^{\circ}C$) was more significant. These results are thought to be poor evaporation properties (distillation) and high molecular weight of the biodiesel.

A simulation study on synthesis gas process optimization for FT(Fischer-Tropsh) synthesis (FT(Fischer-Tropsh) 합성유 제조를 위한 합성가스 공정 최적화 연구)

  • Kim, Yong-Heon;Lee, Won-Su;Lee, Heoung-Yeoun;Koo, Kee-Young;Song, In-Kyu
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.888-888
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    • 2009
  • A simulation study on SCR (Steam Carbon dioxide Reforming) process in gas-to-liquid (natural gas to Fischer-Tropsch synthetic fuel) process was carried out in order to find optimum reaction conditions for GTL (gas-to-liquid) process reaction. Optimum SCR operating conditions for synthesis gas to FT (Fischer-Tropsch) process were determined by changing reaction variables such as feed temperature and pressure. During the simulation, overall synthesis process was assumed to proceed under steady-state conditions. It was also assumed that physical properties of reaction medium were governed by RKS (Redlich-Kwong-Soave) equation. SCR process was considered as reaction models for synthesis gas in GTL proess. The effect of temperature and pressure on SCR process $H_2$/CO ratio and the effect of reaction pressure on SCR reaction were mainly examined. Simulation results were also compared to experimental results to confirm the reliability of simulation model. Simulation results were reasonably well matched with experimental results.

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