Effect of Hydrocarbon on DeNOx Performance of Selective Catalytic Reduction by a Combined Reductant over Cu-Containing Zeolite Catalysts

Heo, Iljeong; Sung, Sam-Kyung; Park, Min Bum; Chang, Tae‐Sun; Kim, Young Jin; Cho, Byong K.; Hong, Suk Bong; Choung, Jin Woo; Nam, In−Sik

doi:10.1021/acscatal.9b02763

Cited by 44 publications

(15 citation statements)

References 37 publications

(125 reference statements)

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“…At ambient pressure, ndodecane presence led to a catalytic activity reduction of up to 17% (Figure 5). Even before the onset of its conversion, n-dodecane showed a strong inhibitory effect, most probably due to adsorption and blockage of the active sites [43]. The diffusion and significant adsorption of n-dodecane into the larger pores of the ZSM-5 framework could be demonstrated by a temperature programmed desorption (TPD) experiment after simultaneous adsorption of NH3 and C12H26 at 150 °C (Figure S8).…”

Section: Impact Of Elevated Pressure and Hydrocarbon Presence On No X Conversionmentioning

confidence: 99%

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

et al. 2021

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Positioning the catalysts in front of the turbocharger has gained interest over recent years due to the earlier onset temperature and positive effect of elevated pressure. However, several challenges must be overcome, like presence of higher pollutant concentrations due to the absence or insufficient diesel oxidation catalyst volume at this location. In this context, our study reports a systematic investigation on the effect of pressure and various hydrocarbons during selective catalytic reduction (SCR) of NOx with NH3 over the zeolite-based catalysts Fe-ZSM-5 and Cu-SSZ-13. Using a high-pressure catalyst test bench, the catalytic activity of both zeolite catalysts was measured in the presence and absence of a variety of hydrocarbons under pressures and temperatures resembling the conditions upstream of the turbocharger. The results obtained showed that the hydrocarbons are incompletely converted over both catalysts, resulting in numerous byproducts. The emission of hydrogen cyanide seems to be particularly problematic. Although the increase in pressure was able to improve the oxidation of hydrocarbons and significantly reduce the formation of HCN, sufficiently low emissions could only be achieved at high temperatures. Regarding the NOx conversion, a boost in activity was obtained by increasing the pressure compared to atmospheric reaction conditions, which compensated the negative effect of hydrocarbons on the SCR activity.

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Section: Impact Of Elevated Pressure and Hydrocarbon Presence On No X Conversionmentioning

confidence: 99%

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

et al. 2021

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“…There are several other issues besides accelerated soot accumulation for the SCRoF exacerbated by a close-coupled configuration. The high density of Brønsted acidity and isolated redox metal sites makes the zeolites-based SCR catalysts used with the SCRoF susceptible to hydrocarbon poisoning [64][65][66][67]. The influence of hydrocarbons is of special consideration in the SCRoF since, due to close coupling, the SCR catalyst is more exposed to the hydrocarbons present in the exhaust gases than in the separate CDPF and SCR system.…”

Section: Future Challenges and Developmentsmentioning

confidence: 99%

“…The CHA (and MOR) structure offers an enhanced resistance towards hydrocarbon poisoning due to its small pores of 3.8 Å that can provide a barrier to the diffusion of hydrocarbons that have larger kinetic diameters, e.g., 4.3 Å for straight chain alkanes and alkenes. Significant deactivation, an approximately 25-30% decrease in conversion, in the temperature range of 250-400 • C can still be observed [64][65][66]. Despite numerous publications related to the investigation of the poisoning mechanism, only a few solutions have been suggested.…”

Section: Future Challenges and Developmentsmentioning

confidence: 99%

Aftertreatment Technologies for Diesel Engines: An Overview of the Combined Systems

2021

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The abatement of the pollutants deriving from diesel engines in the vehicle sector still represents an interesting scientific and technological challenge due to increasingly limiting regulations. Meeting the stringent limits of NOx and soot emissions requires a catalytic system with great complexity, size of units, and number of units, as well as increased fuel consumption. Thus, an after-treatment device for a diesel vehicle requires the use of an integrated catalyst technology for a reduction in the individual emissions of exhaust gas. The representative technologies devoted to the reduction of NOx under lean-burn operation conditions are selective catalytic reduction (SCR) and the lean NOx trap (LNT), while soot removal is mainly performed by filters (DPF). These devices are normally used in sequence, or a combination of them has been proposed to overcome the drawbacks of the individual devices. This review summarizes the current state of NOx and soot abatement strategies. The main focus of this review is on combined technologies for NOx removal (i.e., LNT–SCR) and for the simultaneous removal of NOx and soot, like SCR-on-Filter (SCRoF), in series LNT/DPF and SCR/DPF, and LNT/DPF and SCR/DPF hybrid systems.

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“…Others parameters related to achieve optimal operation conditions of the SCR-deNO x process with TM/Z catalysts include: the type of reducing agent (light hydrocarbons or ammonia) ( Heo et al, 2019 ), and the type of atmosphere (oxidizing or reducing) ( Gu et al, 2015 ). For instance, Lim et al (2020) studied the SCR-deNO x with CH 4 under wet conditions with cobalt supported over different framework zeolites (small-pore).…”

Section: Catalytic Processes With Transition Metals On Zeolitesmentioning

confidence: 99%

Recent Advances in Catalysis Based on Transition Metals Supported on Zeolites

et al. 2021

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This article reviews the current state and development of thermal catalytic processes using transition metals (TM) supported on zeolites (TM/Z), as well as the contribution of theoretical studies to understand the details of the catalytic processes. Structural features inherent to zeolites, and their corresponding properties such as ion exchange capacity, stable and very regular microporosity, the ability to create additional mesoporosity, as well as the potential chemical modification of their properties by isomorphic substitution of tetrahedral atoms in the crystal framework, make them unique catalyst carriers. New methods that modify zeolites, including sequential ion exchange, multiple isomorphic substitution, and the creation of hierarchically porous structures both during synthesis and in subsequent stages of post-synthetic processing, continue to be discovered. TM/Z catalysts can be applied to new processes such as CO2 capture/conversion, methane activation/conversion, selective catalytic NOx reduction (SCR-deNOx), catalytic depolymerization, biomass conversion and H2 production/storage.

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Effect of Hydrocarbon on DeNOx Performance of Selective Catalytic Reduction by a Combined Reductant over Cu-Containing Zeolite Catalysts

Cited by 44 publications

References 37 publications

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

Aftertreatment Technologies for Diesel Engines: An Overview of the Combined Systems

Recent Advances in Catalysis Based on Transition Metals Supported on Zeolites

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