Evaluation of Cu-Based SCR/DPF Technology for Diesel Exhaust Emission Control

Lee, Jong H.; Paratore, Michael J.; Brown, David B.

doi:10.4271/2008-01-0072

Cited by 54 publications

(40 citation statements)

References 3 publications

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“…Since NO x reduction performance at low temperatures is often suppressed by slow SCR kinetics and hydrocarbon poisoning, a DOC is often used in upstream of the SCR catalyst. Because soot is often removed from DPF at high temperatures ([650°C), high thermal stability and high-temperature NO reduction activity are both required for the SCR catalyst to remain effective for NO x emission control [1]. SCR based on V 2 O 5 /WO 3 /TiO 2 catalysts have been used commercially for stationary applications since the 1970s.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Copper Loading on the Selective Catalytic Reduction of Nitric Oxide by Ammonia Over Cu-SSZ-13

et al. 2012

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The effect of Cu loading on the selective catalytic reduction of NO x by NH 3 was examined over a series of Cu ion-exchanged (20-80%) SSZ-13 zeolite catalysts. High NO reduction efficiencies (80-95%) were obtained over all catalyst samples between 250 and 500°C, and at the gas hourly space velocity of 200,000 h -1 . Both NO reduction and NH 3 oxidation activities under these conditions were found to increase slightly with increasing Cu loading at low temperatures. However, NO reduction activity was suppressed with increasing Cu loadings at high temperatures ([500°C) due to excess NH 3 oxidation. The optimum Cu ion exchange level appears to be *40-60% since higher than 80% NO reduction efficiency was obtained over 50% Cu ion-exchanged SSZ-13 up to 600°C. The NO oxidation activity of Cu-SSZ-13 was found to be low regardless of Cu loading, although it was somewhat improved with increasing Cu ion exchange level at high temperatures. During the ''fast'' SCR (i.e., NO/ NO 2 = 1), only a slight improvement in NO x reduction activity was obtained for Cu-SSZ-13. Regardless of Cu loading, near 100% selectivity to N 2 was observed; only a very small amount of N 2 O was produced even in the presence of NO 2 . The apparent activation energies for NO oxidation and NO SCR were estimated to be *58 and *41 kJ/mol, respectively.

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Section: Introductionmentioning

confidence: 99%

The Effect of Copper Loading on the Selective Catalytic Reduction of Nitric Oxide by Ammonia Over Cu-SSZ-13

et al. 2012

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“…In the meantime, efforts are being driven to reduce aftertreatment volume by combining several abatement functions [6]. Thus, new devices, such as the Selective Catalytic Reduction Filter (SCRF) system, are gaining in interest.…”

Section: Introductionmentioning

confidence: 99%

On the Impact of Particulate Matter Distribution on Pressure Drop of Wall-Flow Particulate Filters

et al. 2017

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Wall-flow particulate filters are a required exhaust aftertreatment system to abate particulate matter emissions and meet current and incoming regulations applying worldwide to new generations of diesel and gasoline internal combustion engines. Despite the high filtration efficiency covering the whole range of emitted particle sizes, the porous substrate constitutes a flow restriction especially relevant as particulate matter, both soot and ash, is collected. The dependence of the resulting pressure drop, and hence the fuel consumption penalty, on the particulate matter distribution along the inlet channels is discussed in this paper taking as reference experimental data obtained in water injection tests before the particulate filter. This technique is demonstrated to reduce the particulate filter pressure drop without negative effects on filtration performance. In order to justify these experimental data, the characteristics of the particulate layer are diagnosed applying modeling techniques. Different soot mass distributions along the inlet channels are analyzed combined with porosity change to assess the new properties after water injection. Their influence on the subsequent soot loading process and regeneration is assessed. The results evidence the main mechanisms of the water injection at the filter inlet to reduce pressure drop and boost the interest for control strategies able to force the re-entrainment of most of the particulate matter towards the inlet channels' end.

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“…Nomenclature A. Latin Letters a 1 Constant in channel pressure drop correlation − c m Molecular density of gas mol/m 3 C 1 Parameter for wall permeability correction − C 2 Parameter for wall permeability correction − C 4 Slip correction factor − C P Specific heat capacity J/(kg⋅K) …”

Section: -Scr Crt Modelmentioning

confidence: 99%

“…To answer to those needs, catalyst manufacturers have recently focused on the development of combined SCR/DPF devices (often referred to as SCRF®, WSCR, or SDPF) in which the highly porous walls of the DPF are impregnated with SCR catalytic material. Such devices have been shown to have high NO x conversion capabilities [1,2,4]. Cu-and Fe-zeolitebased catalysts are more appropriate and commonly used as SCR catalysts on DPF due to their higher thermal stability [5].…”

Section: Introductionmentioning

confidence: 99%

Interaction of NO x Reduction and Soot Oxidation in a DPF with Cu-Zeolite SCR Coating

Tronconi

Nova

Marchitti

et al. 2015

Emiss. Control Sci. Technol.

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The combination of selective catalytic reduction (SCR) and diesel particulate filter (DPF) in one system (so called SDPF) enables a very compact design and has already found its way into commercial application for passenger cars. In the case of heavy-duty and non-road applications, the design and control of the SDPF heavily depends on the interaction between NO x reduction and soot oxidation reactions taking place in close vicinity. The governing phenomena are described and studied in the present work by means of multi-scale experimental testing and mathematical modeling. Detailed kinetic studies at a micro-scale laboratory test rig are used to acquire the intrinsic reaction rates of the NH 3 -SCR reactions over a Cu-based catalyst, as well as to obtain qualitative trends of the role of soot presence. The above reaction kinetics are then directly implemented in a physicochemical model of the transport and reaction processes in a wall-flowcatalyzed filter. This model is validated against medium-scale engine tests revealing the competitive effects of SCR and passive soot oxidation, by a simple superposition of SCR chemistry and soot oxidation chemistry. This indicates that proper modeling of the species diffusion processes in the channels, the soot layer, and the wall is sufficient to describe the inhibiting effect of NH 3 -SCR on soot oxidation. This allows for a straightforward decoupled model calibration process which can be used to develop efficient system design and dosing control methodologies. Finally, the model is applied to a much different SDPF scale relevant for large non-road engines. The necessary adaptations to the model parameters are discussed as well as a methodology to apply predictive simulation tools when the boundary conditions are changed.

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Evaluation of Cu-Based SCR/DPF Technology for Diesel Exhaust Emission Control

Cited by 54 publications

References 3 publications

The Effect of Copper Loading on the Selective Catalytic Reduction of Nitric Oxide by Ammonia Over Cu-SSZ-13

The Effect of Copper Loading on the Selective Catalytic Reduction of Nitric Oxide by Ammonia Over Cu-SSZ-13

On the Impact of Particulate Matter Distribution on Pressure Drop of Wall-Flow Particulate Filters

Interaction of NO x Reduction and Soot Oxidation in a DPF with Cu-Zeolite SCR Coating

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