The effects of Fe2O3 based DOC and SCR catalyst on the exhaust emissions of diesel engines

Reşi̇toğlu, İbrahim Aslan; Altınışık, Kemal; Keskïn, Ali; Ocakoğlu, Kasım

doi:10.1016/j.fuel.2019.116501

Cited by 45 publications

(11 citation statements)

References 20 publications

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“…This situation is thought to be caused by the decrease in O 2 concentration in the exhaust gas due to the increase of engine loads. Similar results were determined by Resitoğlu et al and Keskin et al[25,26].…”

supporting

confidence: 90%

The effect of H2O on the use of ethanol as reductant in the SCR system

Keskin

2021

European Mechanical Science

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In this experimental study, effects of H 2 O on the use of ethanol as reducing agents were investigated on the Ag-Pt-W-Ti/Cordierite catalyst. Ag-Pt-W-Ti/Cordierite catalyst was synthesized using the impregnation method for selective catalytic reduction (SCR) of NO x . To investigate the effects of H 2 O addition on the NO x conversion ratios, tests were carried out at 200-270 ° C under 30000 h -1 GHSV using three different reductants (ethanol, 5% H 2 O -95% ethanol, 10% H 2 O -90% ethanol). The catalytic activity of the catalyst increased with increase in exhaust gas temperature. The highest NO x conversion ratio was 89.9% at 270 o C with ethanol. The tests showed that when the H 2 O content of the reductant increased from 5% to 10%, the NO x conversion ratios significantly decreased at temperatures below 240 o C. NO x conversion ratios enhanced as engine load increased.

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confidence: 90%

The effect of H2O on the use of ethanol as reductant in the SCR system

Keskin

2021

European Mechanical Science

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“…Current SCR processes are conducted worldwide to control both NO x and hydrocarbons (HC) pollutant emissions including the NH 3 -SCR, HC-SCR, and urea-SCR among other SCR technologies [2,[8][9][10][11][12]. Alternatively, another reaction employing SCR is the direct denitrification, 110) and (182), respectively.…”

Section: Introductionmentioning

confidence: 99%

Selective Catalytic Reduction of NOx by CO over Doubly Promoted MeMo/Nb2O5 Catalysts (Me = Pt, Ni, or Co)

et al. 2020

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Doubly promoted MeMo/Nb2O5 catalysts, in which Me = Pt, Ni, or Co oxides were prepared for the selective catalytic reduction of NOx by CO reaction (CO-SCR). Comparable chemical, textural, and structural analyses revealed similarities between NiMo and CoMo impregnated on Nb2O5, in contrast to PtMo sites, which were not homogeneously dispersed on the support surface. Both the acid function and metal dispersion gave a synergistic effect for CO-SCR at moderate temperatures. The reactivity of PtMo catalysts towards NOx and CO chemisorption was at low reaction temperatures, whereas the NOx conversion over CoMo was greatly improved at relatively high temperatures. Careful XPS, NH3-TPD, and HRTEM analyses confirmed that the large amounts of strong and moderate acid sites from PtOx entrapped on MoO3 sites induced high NOx conversions. NiMo/Nb2O5 showed poor performance in all conditions. Poisoning of the MeMo sites with water vapor or SO2 (or both) provoked the decline of the NOx conversions over NiMo and PtMo sites, whereas the structure of CoMo ones remained very active with a maximum NOx conversion of 70% at 350 °C for 24 h of reaction. This was due to the interaction of the Co3+/Co2+ and Mo6+ actives sites and the weak strength Lewis acid Nb5+ ones, as well.

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“…To comply with the legislation limits, possible solutions are a combination of a Diesel oxidation catalyst (DOC) [4,5], a diesel particulate filter (DPF) [6,7], a lean NO x trap (LNT) [8,9] or a selective catalytic reduction (SCR) system [10][11][12]. Among the lean NO x aftertreatment technologies, the selective catalytic reduction (SCR) technology shows impressive NO x reduction efficiency, durable performance, reasonable cost, and available infrastructure [13].…”

Section: Introductionmentioning

confidence: 99%

A numerical model for diesel engine SCR systems under different inlet NH₃ distribution profiles

d'Apolito

Hu²

2023

Eng. Res. Express

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Selective Catalytic Reduction (SCR) technology is currently used to effectively reduce NOx emissions for diesel engines. The present study aims at building a three-dimensional numerical model to evaluate the NOx conversion efficiency and the NH3 slip in an SCR system, reducing the time and resources necessary for design and development process. A numerical model of an SCR system has been built to integrate species transport, heat transfer and flow characteristics along with kinetics of the chemical reactions. In order to systematically simulate situations where the concentration of NH3 at the inlet is not uniform, different NH3 inlet profiles have been built by using a Multivariate Gaussian Distribution and considering the maximum concentration in different locations. The effect of different geometries and NH3 distribution profiles on the NOx conversion efficiency and NH3 slip has been studied. The behavior of the system at different inlet temperatures has been explored and the reaction rates in the monolith have been analyzed. The study has been extended by studying the effect of different NH3/NO ratios to provide a more complete comparison between different designs. The numerical model has been found useful to take into account many aftertreatment system parameters during the design of an SCR system, maximize the NOx conversion efficiency by modifying the NH3/NO ratio while minimizing the NH3 slip, providing a comprehensive tool for the optimization of geometrical characteristics of an SCR system.

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The effects of Fe2O3 based DOC and SCR catalyst on the exhaust emissions of diesel engines

Cited by 45 publications

References 20 publications

The effect of H2O on the use of ethanol as reductant in the SCR system

The effect of H2O on the use of ethanol as reductant in the SCR system

Selective Catalytic Reduction of NOx by CO over Doubly Promoted MeMo/Nb2O5 Catalysts (Me = Pt, Ni, or Co)

A numerical model for diesel engine SCR systems under different inlet NH₃ distribution profiles

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The effects of Fe2O3 based DOC and SCR catalyst on the exhaust emissions of diesel engines

Cited by 45 publications

References 20 publications

The effect of H2O on the use of ethanol as reductant in the SCR system

The effect of H2O on the use of ethanol as reductant in the SCR system

Selective Catalytic Reduction of NOx by CO over Doubly Promoted MeMo/Nb2O5 Catalysts (Me = Pt, Ni, or Co)

A numerical model for diesel engine SCR systems under different inlet NH3 distribution profiles

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Product

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A numerical model for diesel engine SCR systems under different inlet NH₃ distribution profiles