Papers by Keyword: NH3-SCR

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Authors: Qiu Lin Zhang, Xin Liu, Ping Ning, Hao Li, Zhong Xian Song, Jun Jie Gu
Abstract: Ce-Ti-MoOx catalysts with different Mo contents have been prepared and used for selective catalytic reduction of NO with NH3 (NH3-SCR). As-prepared catalysts were characterized by N2 adsorption-desorption and XRD analysis. It was found that the Ce-Ti-MoOx catalyst with nominal MoO3 content of 10 % exhibited the best NH3-SCR activity, over 90 % of NO conversions could be obtained at 200 - 425 °C with GHSV of 100 000 h-1.
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Authors: Xue Wang, Jian Wang, Ting Yu Zhu
Abstract: The V2O5/TiO2 catalyst is used to control chlorobenzene and NO simultaneously in NH3-SCR reaction. XRD characterization of the catalyst is carried out. The effect of NO and NH3 on the chlorobenzene catalytic conversion is studied and opposite results are concluded. NO slightly increases the catalytic conversion rate of chlorobenzene under 250oC while NH3 obviously declines the chlorobenzene catalytic degradation at 300oC. The best coupled control efficiency can be achieved at 350 oC.
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Authors: Kai Qi, Jun Lin Xie, Feng Xiang Li, Feng He
Abstract: The samples of MnOx/TiO2 catalysts supported on cordierite honeycomb ceramics were prepared by a sol-gel-impregnation method, and evaluated for low-temperature (353-473 K) selective catalytic reduction (SCR) of NOx with NH3. The influences of pretreatment on cordierite and catalyst dosage were investigated at first and optimized as follows: pickling for cordierite honeycomb ceramics with 1 mol/L HNO3 for 3 h prior to loading procedure as well as the catalyst dosage of 3-5 wt.%. The activity results indicated that there was an optimum working condition for MnOx/TiO2/cordierite catalysts: NH3/NO molar ratio=1.1, [O2]=3 vol.%, GHSV=5514 h-1, the highest activity of nearly 100% NO conversion could be obtained. As a comparison, the performances of commercialized vanadium-based honeycomb catalyst were also employed, which revealed the narrower scope of application of GHSV and the higher active temperature window. In conclusion, it turns out that the prepared MnOx/TiO2/cordierite catalysts are more applicable as a low-temperature SCR catalyst for NOx removal in a more complicated application environment.
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Authors: Xin Na Tian, You Hong Xiao, Wen Ping Zhang, Yong Wei Chen
Abstract: The most potential method of selective catalytic reduction (SCR) to remove NOx from diesel engine emissions is very effective in NOx reduction with an efficiency up to 95%. However, the current SCRs have a limitation on operation temperature and a narrow operation temperature window. In this paper, the V-W based catalysts were used in the investigation to improve the low temperature performance of NOx conversion by doping Cu and Mn into V-W based catalyst. The temperature range studied was between 150 °C and 550 °C with an interval of 50 °C. The honeycomb catalysts were prepared by an impregnation method. The study also included characterization of catalysts by BET, XRD, TPD and XPS methods.It is found that NOx conversion performance of the V-W based catalyst increases with the increase of reaction temperature. After the metal Cu or Mn doped into the catalyst, it offers an improvement in the catalytic performance. Among all the catalysts studied, the mixed metal catalyst of Cu-Mn-V-W catalyst is found the most potential one, not only because of its higher NOx conversion rate at a low temperature, but also because of its wider operation temperature window.
811
Authors: De Fang, Feng He, Xiao Qing Liu, Jun Lin Xie
Abstract: A series of Mn-based spinels over TiO2 catalysts have been prepared with the impregnation method. Catalysts were comprehensively characterized using XRD, FESEM, H2-TPR, and the activity evaluation of NH3-SCR, while long-time stability tests and the effect of H2O on NH3-SCR were also investigated. Meanwhile, K poisoning effect was studied by preparing K-doped catalysts (K-Mn/TiO2, K-Cu-Mn/TiO2, K-Mg-Mn/TiO2 and K-Co-Mn/TiO2). According to the characterizations, Cu-Mn/TiO2, Mg-Mn/TiO2 and Co-Mn/TiO2 catalysts exhibited superior low-temperature SCR activity, stability, K resistance and H2O resistance due to the formation of spinels (MgMn2O4, CoMn2O4, CuMn2O4).
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Authors: Min Kang, Jae Hyun Park, Eun Duck Park, Ji Man Kim, Dae Jung Kim, Jae Eui Yie
Abstract: The selective catalytic reduction of NOx with NH3 (NH3-SCR) was investigated over Pt catalysts supported on various supports such as alumina, ZSM-5, SBA-15, and Al-SBA-15 with different amounts of alumina. Among them, Pt catalysts supported on Al-SBA-15 showed the higher NOx conversion at low temperatures than those of others. These also showed high NOx conversions over a wide reaction temperature. As the Si/Al ratio in Al-SBA-15 decreased, the NH3-SCR activity increased. This was closely related to the amount of strongly-adsorbed NH3.
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