Control of NO<sub>x</sub>Emissions from Diesel Engine by Selective Catalytic Reduction (SCR) with Urea

Baik, Joon Hyun; Yim, Sung Dae; Nam, In−Sik; Mok, Young Sun; Lee, Jong‐Hwan; Cho, Byong K.; Oh, Se H.

doi:10.1023/b:toca.0000029725.88068.97

Cited by 133 publications

(48 citation statements)

References 8 publications

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“…105,128,130 It is generally accepted that the active sites in the SCR reaction of Cu-based zeolites, including Cu-ZSM-5, Cu-beta and Cu-FAU, are mainly dimerized Cu 2+ and Cu + species, and the facility of redox between Cu 2+ and Cu + is beneficial to high SCR performance. 10,128,[131][132][133][134][135] Through studies on the variation of SCR activity and the alteration of catalytically active sites, Park et al 131 attributed the hydrothermal deactivation of Cu-ZSM-5 catalysts to the migration and re-distribution of Cu 2+ species, leading to the decrease of active sites and the blockage of zeolite channels by sintered CuO, together with the dealumination and collapse of the zeolite support. After hydrothermal treatment of Cu-beta catalysts under different conditions (500-900 1C, 3% H 2 O), Wilken et al 134 found that the zeolite structure showed no obvious change below 800 1C, yet the oxidation state of Cu species showed apparent change, with a decrease in Cu + species and increase in Cu 2+ species as indicated by XPS results.…”

Section: Nh 3 -Scr Of No X Over Zeolite Catalystsmentioning

confidence: 99%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

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Selective catalytic reduction of NO x using NH 3 or hydrocarbons (NH 3 -SCR or HC-SCR) in oxygen-rich exhaust from diesel engines remains a major challenge in environmental catalysis. The development of highly efficient, stable and environmentally-benign catalysts for SCR processes is very important for practical use. In this feature article, the structure-activity relationship of vanadium-free catalysts in the NH 3 -SCR reaction is discussed in detail, including Fe-, Ce-based oxide catalysts and Fe-, Cu-based zeolite catalysts, which is beneficial for catalyst redesign and activity improvement. Based on our research, a comprehensive mechanism contributing to the performance of Ag/Al 2 O 3 in HC-SCR is provided, giving a clue to the design of a catalytic system with high efficiency.

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Section: Nh 3 -Scr Of No X Over Zeolite Catalystsmentioning

confidence: 99%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

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“…Copper-based zeolites have been suggested as efficient catalysts for the NH 3 -SCR reaction [2][3][4][5], and Cu-ZSM-5 was proposed to be the most promising [6,7]. However, the structure of the Cu-ZSM-5 catalyst collapsed easily after high temperature hydrothermal aging, leading to a conspicuous decline in NH 3 -SCR activity [8].…”

Section: Introductionmentioning

confidence: 99%

High hydrothermal stability of Cu–SAPO-34 catalysts for the NH3-SCR of NOx

Niu

Shi

Liu

et al. 2016

Chemical Engineering Journal

122

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“…On the other hand, SCR with urea offers attractive solutions at low temperature and, often, serious aging and durability problems appear when high temperature conditions are imposed [24]. Similar results were found when LNTs are used for light-duty (LD) applications with traditional diesel combustion [6].…”

Section: Introductionmentioning

confidence: 73%

A numerical analysis of energetic performances of active and passive aftertreatment systems

Algieri¹,

Amelio²,

Morrone³

2009

Int. J. Energy Res.

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SUMMARYThe present work aims to analyze the thermal and the energetic performances of an aftertreatment system with unidirectional and periodic reversal flow within the device. To this purpose a single-channel one-dimensional model was developed in order to assess the heat exchange between the aftertreatment system and the exhaust gas. Furthermore, the temperature profiles of the gas and solid phase were computed and the calculated temperatures were adopted to characterize the energy effectiveness of the aftertreatment system. The comparison between different control modes showed an increase in the heat retention efficiency of the system with reverse flow at low engine load conditions. Conversely, the system with passive thermal management presented higher temperatures of the monolith during the warm-up operations. Furthermore, the influence of unburned hydrocarbons oxidation on the effectiveness of the aftertreatment system was evaluated and the significant influence of the cycle time and the monolith length on the system performance was shown. Finally, the gas residence time was evaluated for different operating conditions.

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Control of NO_xEmissions from Diesel Engine by Selective Catalytic Reduction (SCR) with Urea

Cited by 133 publications

References 8 publications

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

High hydrothermal stability of Cu–SAPO-34 catalysts for the NH3-SCR of NOx

A numerical analysis of energetic performances of active and passive aftertreatment systems

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Control of NOxEmissions from Diesel Engine by Selective Catalytic Reduction (SCR) with Urea

Cited by 133 publications

References 8 publications

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

High hydrothermal stability of Cu–SAPO-34 catalysts for the NH3-SCR of NOx

A numerical analysis of energetic performances of active and passive aftertreatment systems

Contact Info

Product

Resources

About

Control of NO_xEmissions from Diesel Engine by Selective Catalytic Reduction (SCR) with Urea

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects