scholarly journals Comparative Study of SO2 and SO2/SO3 Poisoning and Regeneration of Cu/BEA and Cu/SSZ-13 for NH3 SCR

2021 ◽  
Author(s):  
Xavier Auvray ◽  
Maria Arvanitidou ◽  
Åsa Högström ◽  
Jonas Jansson ◽  
Sheedeh Fouladvand ◽  
...  
Keyword(s):  
Selective Reduction ◽  
Sulfur Poisoning ◽  
Nh3 Scr ◽  
Activity Measurements ◽  
Small Pore ◽  
Before And After ◽  
Fast Scr ◽  
Diffuse Reflectance Infrared ◽  
Partial Activity ◽  
Scr No

AbstractTwo copper-exchanged zeolites, Cu/SSZ-13 and Cu/BEA, were studied as catalysts for the selective reduction of NOx by NH3 (NH3-SCR). Their activities for standard SCR (NOx = NO) and fast SCR (NOx = 50% NO + 50% NO2) were measured before and after sulfur poisoning at 250 °C. The effect of 30 ppm SO2 and a mixture of 24 ppm SO3 + 6 ppm SO2 was evaluated. The repetition of subsequent activity measurements served as regeneration method in SCR conditions. SO2 deactivated Cu/SSZ-13 whereas Cu/BEA was only moderately affected. SO3 led to stronger deactivation of both catalysts than SO2. However, also for this case, the Cu/BEA was significantly less affected than Cu/SSZ-13, even though Cu/BEA contained larger amount of stored sulfur. One possible reason for this could be the large pores of Cu/BEA, where the sulfur species possibly resulted in less sterical hindrance than in the small pore SSZ-13 structure. NH3 temperature-programmed desorption (NH3-TPD) showed no loss of storage sites upon sulfur treatment and subsequent regeneration. Partial activity recovery was observed after a period in SCR conditions at 400 °C and 500 °C. Temperature at 300 °C was insufficient to regenerate the catalysts. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of NO adsorption suggested that SO2 interacts with the ZCuOH sites on Cu/SSZ-13, causing the strong poisoning.

scholarly journals Selective catalytic reduction of NOx with NH3: opportunities and challenges of Cu-based small-pore zeolites

2021 ◽  
Author(s):  
Yulong Shan ◽  
Jinpeng Du ◽  
Yan Zhang ◽  
Wenpo Shan ◽  
Xiaoyan Shi ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Hydrothermal Stability ◽  
Catalyst Design ◽  
Scr Catalyst ◽  
Nh3 Scr ◽  
Small Pore ◽  
Fast Scr ◽  
Reduction Of Nox ◽  
Significant Opportunity

Abstract Zeolites, as efficient and stable catalysts, are widely used in the environmental catalysis field. Typically, Cu-SSZ-13 with small-pore structure shows excellent catalytic activity for selective catalytic reduction of NOx with ammonia (NH3-SCR) as well as high hydrothermal stability. This review summarizes major advances in Cu-SSZ-13 applied to the NH3-SCR reaction, including the state of copper species, standard and fast SCR reaction mechanism, hydrothermal deactivation mechanism, poisoning resistance, and synthetic methodology. The review gives a valuable summary of new insights on the matching between SCR catalyst design principles and the characteristics of Cu2+-exchanged zeolitic catalysts, highlighting the significant opportunity presented by zeolite-based catalysts. Principles for designing zeolites with excellent NH3-SCR performance and hydrothermal stability are proposed. On the basis of these principles, more hydrothermally stable Cu-AEI and Cu-LTA zeolites are elaborated as well as other alternative zeolites applied to NH3-SCR. Finally, we call attention to the challenges facing Cu-based small-pore zeolites that still need to be addressed.

scholarly journals Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 618
Author(s):  
Huan Du ◽  
Zhitao Han ◽  
Xitian Wu ◽  
Chenglong Li ◽  
Yu Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalyst Surface ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Tio2 Catalyst ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
So2 Resistance ◽  
Fast Scr

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

Unraveling the nature of sulfur poisoning on Cu/SSZ-13 as a selective reduction catalyst

2021 ◽  
Vol 118 ◽  
pp. 38-47
Author(s):  
Chen Wang ◽  
Zexiang Chen ◽  
Jun Wang ◽  
Jianqiang Wang ◽  
Meiqing Shen
Keyword(s):  
Selective Reduction ◽  
Sulfur Poisoning

Excellent low-temperature NH3-SCR NO removal performance and enhanced H2O resistance by Ce addition over the Cu0.02Fe0.2CeyTi1-yOx (y = 0.1, 0.2, 0.3) catalysts

Chemosphere ◽  
2020 ◽  
Vol 243 ◽  
pp. 125309 ◽  
Author(s):  
Shibo Ma ◽  
Huansheng Tan ◽  
Yushi Li ◽  
Peiqiang Wang ◽  
Chen Zhao ◽  
...  
Keyword(s):  
Low Temperature ◽  
No Removal ◽  
Nh3 Scr ◽  
Scr No

scholarly journals Structural parameters governing low temperature activity of small pore copper zeolites in NH3-SCR

2020 ◽  
Vol 390 ◽  
pp. 224-236 ◽  
Author(s):  
Michiel De Prins ◽  
Elke Verheyen ◽  
Andreas Hoffmann ◽  
Gina Vanbutsele ◽  
Sreeprasanth Pulinthanathu Sree ◽  
...  
Keyword(s):  
Low Temperature ◽  
Structural Parameters ◽  
Nh3 Scr ◽  
Small Pore

scholarly journals Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 492
Author(s):  
Jesus Emmanuel De Abreu Goes ◽  
Annika Kristoffersson ◽  
Louise Olsson
Keyword(s):  
Flow Reactor ◽  
Sulfur Removal ◽  
Sulfur Poisoning ◽  
Lean Nox Trap ◽  
Nox Trap ◽  
So2 Poisoning ◽  
Lean Nox ◽  
Micro Flow ◽  
Diffuse Reflectance Infrared ◽  
Sulfate Species

In the present work, a series of different materials was investigated in order to enhance the understanding of the role of modern lean NOx trap (LNT) components on the sulfur poisoning and regeneration characteristics. Nine different types of model catalysts were prepared, which mainly consisted of three compounds: (i) Al2O3, (ii) Mg/Al2O3, and (iii) Mg/Ce/Al2O3 mixed with Pt, Pd, and Pt-Pd. A micro flow reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were employed in order to investigate the evolution and stability of the species formed during SO2 poisoning. The results showed that the addition of palladium and magnesium into the LNT formulation can be beneficial for the catalyst desulfation due mainly to the ability to release the sulfur trapped at relatively low temperatures. This was especially evident for Pd/Mg/Al2O3 model catalyst, which demonstrated an efficient LNT desulfation with low H2 consumption. In contrast, the addition of ceria was found to increase the formation of bulk sulfate species during SO2 poisoning, which requires higher temperatures for the sulfur removal. The noble metal nature was also observed to play an important role on the SOx storage and release properties. Monometallic Pd-based catalysts exhibited the formation of surface palladium sulfate species during SO2 exposure, whereas Pt-Pd bimetallic formulations presented higher stability of the sulfur species formed compared to the corresponding Pt- and Pd-monometallic samples.

Sulfur poisoning of emergent and current electrocatalysts: vulnerability of MoS2, and direct correlation to Pt hydrogen evolution reaction kinetics

Nanoscale ◽  
2015 ◽  
Vol 7 (19) ◽  
pp. 8879-8883 ◽  
Author(s):  
Shu Min Tan ◽  
Zdeněk Sofer ◽  
Martin Pumera
Keyword(s):  
Reaction Kinetics ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Sulfur Poisoning ◽  
Before And After

The impacts of sulfur poisoning on both MoS2 and Pt were examined through comparisons between their HER electrocatalytic activities before and after poisoning. In particular, the poisoning of Pt was directly correlated to its HER performance.

Phosphorus modified small-pore zeolites and their catalytic performances in ethanol conversion and NH3-SCR reactions

2019 ◽  
Vol 575 ◽  
pp. 204-213 ◽  
Author(s):  
Yutaro Kakiuchi ◽  
Takuya Tanigawa ◽  
Nao Tsunoji ◽  
Yasuyuki Takamitsu ◽  
Masahiro Sadakane ◽  
...  
Keyword(s):  
Ethanol Conversion ◽  
Nh3 Scr ◽  
Small Pore ◽  
Catalytic Performances

scholarly journals Deactivation and Regeneration for the SO2-Poisoning of a Cu-SSZ-13 Catalyst in the NH3-SCR Reaction

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 797 ◽  
Author(s):  
Yan Wang ◽  
Zhaoqiang Li ◽  
Rongrong Fan ◽  
Xin Guo ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Active Sites ◽  
Sulfur Poisoning ◽  
Photoelectron Spectra ◽  
Hydrothermal Aging ◽  
Exponential Factor ◽  
Nh3 Scr ◽  
So2 Poisoning ◽  
Scr Catalysts ◽  
Temperature Programmed ◽  
Redox Ability

Cu-SSZ-13 has been generally considered as the predominant commercial selective catalytic reduction (SCR) catalyst in the NH3-SCR reaction because of its superior activity and durability. However, in real applications, SCR catalysts readily undergo hydrothermal aging and sulfur poisoning. In this work, the deactivation and regeneration of a commercial Cu-SSZ-13 catalyst was investigated for SO2 exposures during hydrothermal aging and the effect of different regeneration temperatures was compared. By using XRD, SEM, H2-temperature programmed reduction (TPR), X–ray photoelectron spectra (XPS) and NH3-temperature programmed desorption (TPD) analysis, it was found that SO2 poisoning influenced the chabazite (CHA) structure even if regeneration cannot restore its original structure, the redox ability and ammonia storage performance also influenced by sulfation and the regeneration process. Moreover, the extent of a decrease in redox ability was more severe than acidity, suggesting that the amount of isolated Cu2+ and Cu+ reduction was responsible for irreversible deactivation over the Cu-SSZ-13 catalyst. Combined with the analysis of Ea values and pre-exponential factor of the SCR reaction, a more likely explanation for the irreversible deactivation was that active sites were lost mostly in sulfated and regenerated process sites.

Sign in / Sign up

Export Citation Format

Share Document