Impact of SO2-poisoning over the lifetime of a Cu-CHA catalyst for NH3-SCR

Hammershøi, Peter S.; Jensen, Anker Degn; Janssens, Ton V. W.

doi:10.1016/j.apcatb.2018.06.039

Cited by 64 publications

(55 citation statements)

References 24 publications

(80 reference statements)

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“…14 Deactivation by SO2 is almost immediate: at about 1% of the total lifetime exposure to SO2, the activity is reduced to about 30% of the original activity, and it stabilizes at about 10% of the original activity after 5-10% of the lifetime SO2 exposure. 17 The sulfur uptake in the Cu-CHA catalyst follows a similar pattern as the activity and, dependent on the temperature, a maximum S/Cu molar ratio of 0.5-1 is reached. The observation that the S/Cu ratio usually does not exceed 1 points to the formation of Cu,S species.…”

Section: Introductionmentioning

confidence: 65%

“…Ultra-low sulfur diesel contains less than 10 wt ppm (Europe) or 15 wt ppm (US) sulfur, and the SO2 concentration in the exhaust gas typically reaches a few ppmv, which is nevertheless sufficient to reduce the low-temperature activity of the Cu-CHA catalysts significantly. [13][14][15][16][17][18][19][20][21][22][23][24] To be able to preserve the good lowtemperature activity, it is important to understand the impact of SO2 on the NH3-SCR activity of Cu-CHA based catalysts. We have recently shown that deactivation of Cu-CHA catalysts depends on the total SO2 exposure, which is the product of the SO2 concentration and the exposure time.…”

Section: Introductionmentioning

confidence: 99%

“…The observation that the S/Cu ratio usually does not exceed 1 points to the formation of Cu,S species. 13,14,17 Thermal regeneration at 550 °C, which is feasible in a typical EURO VI exhaust system, can restore most of the activity if carried out in SO2-free gas. 13,14,17 During the regeneration, SO2 is released from the catalyst, but a certain fraction of the sulfur is retained in a stable form that resemble Cu sulfate.…”

Section: Introductionmentioning

confidence: 99%

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Site selective adsorption and relocation of SO_x in deactivation of Cu–CHA catalysts for NH₃-SCR

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Section: Introductionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Site selective adsorption and relocation of SO_x in deactivation of Cu–CHA catalysts for NH₃-SCR

et al. 2019

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“…Studies have shown that transition metal oxides such as FeO X , CuO X , MnO X, and NiO X can be used as active components to catalyze NO X reduction. For example, deNO X performance over Cu‐zeolite catalysts showed high NO X conversion in a temperature range of 180–300 °C and Mn/biomass‐char catalysts could achieve NO conversion as high as 87.6 % at 200 °C . Combining Mn and Fe can create a synergistic effect in which more than 90 % NO X conversion can be maintained while using a temperature range of 200–250 °C .…”

Section: Introductionmentioning

confidence: 99%

Deactivation mechanism of activated carbon supported copper oxide SCR catalysts in C₂H₄ reductant

et al. 2019

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Current state‐of‐the‐art NH3‐SCR technology based on vanadium catalysts suffers problems associated with NH3 slip and poisoning of the catalyst and blockage of heat recovery steam generators (HRSG). If environmentally‐friendly catalysts capable of efficient operation at lower temperatures could be developed that used a reductant other than NH3, the issues with current state‐of‐the‐art SCR could be significantly lessened. Hence, in this study, activated carbon (AC) supported copper oxide‐based catalysts for SCR while using C2H4 as a reductant was discussed. Reaction testing of catalysts demonstrated high initial NO conversion with steeply declining activity over 2 h of testing when C2H4 was used as the reductant; in comparison, with the same catalyst and NH3 as the reductant, stable, long‐term NO conversion was achieved, but at a lower rate than the initial reactivity with C2H4. As a consequence, catalyst characterization studies were performed to assess deactivation mechanisms when C2H4 was the reductant. These studies included x‐ray diffraction, BET surface area and porosity, temperature programmed reduction, scanning electron microscopy, Raman spectroscopy and x‐ray photoelectron spectroscopy of both fresh and deactivated catalysts. The analytical results showed the surface area and porosity of the catalyst remained unchanged and the initially highly‐dispersed Cu species became agglomerated and more crystalline during reaction testing. Furthermore, carbon black was also detected on the catalyst surface after testing, presumably formed during the decomposition of C2H4. Both agglomeration of the active Cu species and blockage by carbon deposits would decrease the availability of active sites and lead to decreased catalytic activity.

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“…Removal of NO x by reduction is an extraordinary efficient method for removing NO x . However, SCR is limited by a series of problems, such as high cost, high temperature at 300 • C, NH 3 escaping from secondary pollution environment [213], poor sulfur and water resistance of catalysts and susceptibility to poisoning and inactivation [214,215], which affect the life of the catalysts, makes the treatment and operation cost significantly higher [216,217]. Therefore, how to promote the resource-saving and environmentally friendly denitrification process is a difficult problem to be solved urgently in the world [218].…”

Section: H 2 -Scrmentioning

confidence: 99%

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

Liu

et al. 2019

Catalysts

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Nitrogen oxides (NO x ) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NO x , it is urgent to control NO x . According to the different mechanisms of NO x removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NO x . At the same time, the current research status and existing problems of different NO x removal technologies were revealed and the future development prospects were forecasted.Catalysts 2019, 9, 771 2 of 39 adsorption, oxidation, reduction, and plasma methods. In view of these attentive findings, adsorption method uses recyclable solid adsorbent material to adsorb NO x from flue gas through microporous structure, remarkably, environmentally friendly, no secondary pollution, and energy-saving and -efficient features make it stand out [18][19][20]. The oxidation process is a method that oxidizes NO into NO 2 or N 2 O 3 with high solubility under the action of an oxidant that is then absorbed by water or alkali solution. The process is simple and cost-saving, and is widely used in the wet flue gas denitrification process with relatively low cost and high removal efficiency of NO x ; except that the oxidized NO and SO 2 can be removed simultaneously to produce high value-added products [21][22][23]. The reduction method has the characteristics of high efficiency, cleanliness, and mildness; NO x removal can be realized at low temperature at present [24][25][26]. The plasma method is used to modify the surface of the catalyst, the dispersion of active species can be improved by plasma treatment, and the stability and low temperature activity of catalyst can be improved [27,28].Seldom, if ever, does a comprehensive article to introduce the current situation and treatment methods of removing NO x . In this paper, we tried to renovate, classify, and summarize the significant perspectives and most relevant findings reported in recent research articles and earlier reviews generalizing the mechanism analysis and research progress of NO x removal by adsorption, oxidation, reduction, and plasma methods, which can provide means for promoting the technological progress of pollution prevention, maintaining healthy development of factories continuously, studying the methods of removing NO x deeply, and mastering different technologies of removing NO x , as well as providing guidance for controlling the emission of NO x from motor vehicles such as diesel, gasoline, and so on. In order to improve the environmental quality and save the ecological environment, this paper further provides a convenient, low-cost, efficient, and economic guidance line.

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Impact of SO2-poisoning over the lifetime of a Cu-CHA catalyst for NH3-SCR

Cited by 64 publications

References 24 publications

Site selective adsorption and relocation of SO_x in deactivation of Cu–CHA catalysts for NH₃-SCR

Site selective adsorption and relocation of SO_x in deactivation of Cu–CHA catalysts for NH₃-SCR

Deactivation mechanism of activated carbon supported copper oxide SCR catalysts in C₂H₄ reductant

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

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Impact of SO2-poisoning over the lifetime of a Cu-CHA catalyst for NH3-SCR

Cited by 64 publications

References 24 publications

Site selective adsorption and relocation of SOx in deactivation of Cu–CHA catalysts for NH3-SCR

Site selective adsorption and relocation of SOx in deactivation of Cu–CHA catalysts for NH3-SCR

Deactivation mechanism of activated carbon supported copper oxide SCR catalysts in C2H4 reductant

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

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Site selective adsorption and relocation of SO_x in deactivation of Cu–CHA catalysts for NH₃-SCR

Site selective adsorption and relocation of SO_x in deactivation of Cu–CHA catalysts for NH₃-SCR

Deactivation mechanism of activated carbon supported copper oxide SCR catalysts in C₂H₄ reductant