scholarly journals SO2 Poisoning and Recovery of Copper-Based Activated Carbon Catalysts for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1426
Author(s):  
Marwa Saad ◽  
Agnieszka Szymaszek ◽  
Anna Białas ◽  
Bogdan Samojeden ◽  
Monika Motak
Keyword(s):  
Activated Carbon ◽  
Selective Catalytic Reduction ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Exhaust Gas ◽  
Impregnation Method ◽  
No Conversion ◽  
So2 Poisoning ◽  
Carbon Catalysts

A series of materials based on activated carbon (AC) with copper deposited in various amounts were prepared using an incipient wetness impregnation method and tested as catalysts for selective catalytic reduction of nitrogen oxides with ammonia. The samples were poisoned with SO2 and regenerated in order to analyze their susceptibility to deactivation by the harmful component of exhaust gas. NO conversion over the fresh catalyst doped with 10 wt.% of Cu reached 81% of NO conversion at 140 °C and about 90% in the temperature range of 260–300 °C. The rate of poisoning with SO2 was dependent on Cu loading, but in general, it lowered NO conversion due to the formation of (NH4)2SO4 deposits that blocked the active sites of the catalysts. After regeneration, the catalytic activity of the materials was restored and NO conversion exceeded 70% for all of the samples.

A Ce-Zr-Ti Oxide Catalyst for Selective Catalytic Reduction of NO with Ammonia

2014 ◽  
Vol 535 ◽  
pp. 709-712
Author(s):  
Ye Jiang ◽  
Yan Yan ◽  
Shan Bo Huang ◽  
Xiong Zhang ◽  
Xin Wei Wang ◽  
...  
Keyword(s):  
High Activity ◽  
Selective Catalytic Reduction ◽  
Oxide Catalyst ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Impregnation Method ◽  
Reduction Of No ◽  
No Conversion ◽  
Temperature Range ◽  
Ti Oxides

A Ce-Zr-Ti oxide catalyst was prepared by an impregnation method and tested for the selective catalytic reduction of NO with NH3. The Ce-Zr-Ti oxide catalyst exhibited high activity and more than 95% NO conversion was obtained within the temperature range 300-500 °C at the high gas hourly space velocity of 50,000 h-1. The addition of Zr improved the activity of Ce-Ti oxides especially at higher reaction temperatures and their resistance to SO2.

scholarly journals New Insight into the In Situ SO2 Poisoning Mechanism over Cu-SSZ-13 for the Selective Catalytic Reduction of NOx with NH3

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1391
Author(s):  
Yu Qiu ◽  
Chi Fan ◽  
Changcheng Sun ◽  
Hongchang Zhu ◽  
Wentian Yi ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Zeolite Catalysts ◽  
So2 Poisoning ◽  
Negative Effect ◽  
Temperature Programmed ◽  
Diffuse Reflectance Infrared ◽  
Sulfate Species

To reveal the nature of SO2 poisoning over Cu-SSZ-13 catalyst under actual exhaust conditions, the catalyst was pretreated at 200 and 500 °C in a flow containing NH3, NO, O2, SO2, and H2O. Brunner−Emmet−Teller (BET), X-ray diffraction(XRD), thermo gravimetric analyzer (TGA), ultraviolet Raman spectroscopy (UV Raman), temperature-programmed reduction with H2 (H2-TPR), temperature-programmed desorption of NO+O2 (NO+O2-TPD), NH3-TPD, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), and an activity test were utilized to monitor the changes of Cu-SSZ-13 before and after in situ SO2 poisoning. According to the characterization results, the types and generated amount of sulfated species were directly related to poisoning temperature. Three sulfate species, including (NH4)2SO4, CuSO4, and Al2(SO4)3, were found to form on CZ-S-200, while only the latter two sulfate species were observed over CZ-S-500. Furthermore, SO2 poisoning had a negative effect on low-temperature selective catalytic reduction (SCR) activity, which was mainly due to the sulfation of active sites, including Z2Cu, ZCuOH, and Si-O(H)-Al. In contrast, SO2 poisoning had a positive effect on high-temperature SCR activity, owing to the inhibition of the NH3 oxidation reaction. The above findings may be a useful guideline to design excellent SO2-resistant Cu-based zeolite catalysts.

Cu-Supported on Sodium-Treated Sepiolite for Selective Catalytic Reduction of NO by Propylene

2015 ◽  
Vol 1088 ◽  
pp. 569-572
Author(s):  
Zhi Hao Zhang ◽  
Yang Li ◽  
Yun Fang Qi ◽  
Qing Ye ◽  
Shu Lan Ji ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
High Performance ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Redox Species ◽  
Reduction Of No ◽  
Catalytic Activities ◽  
Scr Of No ◽  
Activity Center

Cu/Na-Sep samples were prepared by the incipient wetness impregnation method. These catalysts were characterized by means of XRF, XRD, and XPS techniques, and their catalytic activities were performed by the SCR of NO with propylene. The results show that the Cu/Na-Sep catalyst exhibited the high performance in the C3H6-SCR of NO. After investigation by XRD and XPS, the result showed that there are Cu2+/Cu+redox species as a reaction activity center over Cu/Na-Sep.

scholarly journals Physicochemical and Catalytic Properties of Vanadia/Titania Catalysts. V. Selective Catalytic Reduction of NO with NH3

2002 ◽  
Vol 20 (10) ◽  
pp. 937-945
Author(s):  
Th. El-Nabarawy ◽  
M.N. Alaya ◽  
S.A. Sayed Ahmed ◽  
A.M. Youssef
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Properties ◽  
Catalytic Reduction ◽  
Impregnation Method ◽  
Reduction Of No ◽  
No Conversion ◽  
Scr Of No ◽  
Monolayer Coverage

Vanadia/titania catalysts were prepared containing 6.0 or 8.0 wt% V2O5 via the impregnation method. The samples as prepared were calcined at 400°C or 600°C, respectively. Selective catalytic reduction (SCR) of NO with NH3 was carried out at 257°C over the prepared catalysts. NO conversion as a function of time was followed and the stationary conversion versus the amount of catalyst employed was also investigated. It was found that the vanadia/titania catalysts calcined at 400°C were more active in the SCR of NO with NH3 relative to those calcined at 600°C. This was attributed to such catalysts possessing complete monolayer coverage of vanadia on the titania substrate. It was established that V5+ was not the active vanadia species but V4+ and V3+ may act as such for the SCR of NO with NH3.

Studies on the Preparation and DeNOx Performance of MnxOy/CNTs Catalyst for Low-Temperature Selective Catalytic Reduction

2013 ◽  
Vol 798-799 ◽  
pp. 231-234 ◽  
Author(s):  
Bing Nan Ren ◽  
Qiao Wen Yang
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Oxide Catalyst ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Impregnation Method ◽  
Active Components ◽  
Reaction Conditions ◽  
No Conversion ◽  
Scr Of No

The metal oxide catalyst was prepared by loading MnxOyon carbon nanotubes (CNTs) with impregnation method. Then the catalyst was characterized by BET, TEM and XPS, and the catalytic activity of the catalyst for selective catalytic reduction (SCR) of NO at low-temperature was investigated. The results showed that the species of active components loaded on the catalyst were MnO2and Mn2O3. The NO conversion was improved with reduction temperature increase under 250°C, increased slowly over 250°C. The O2content had an outstanding effect on NO conversion of catalysts at a low concentration range. Once the oxygen content was enhanced over 5%, there was no significant increase in the NO conversion. With the increasing of space velocity, the NO conversion rate was decreased under the reaction conditions.

scholarly journals Low Temperature deNOx Catalytic Activity with C2H4 as a Reductant Using Mixed Metal Fe-Mn Oxides Supported on Activated Carbon

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4341 ◽  
Author(s):  
Fang Liu ◽  
Li Yang ◽  
Jie Cheng ◽  
Xin Wu ◽  
Wenbin Quan ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Low Temperature ◽  
Mixed Oxide ◽  
Active Sites ◽  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Oxide Catalysts ◽  
Catalyst Stability ◽  
No Conversion ◽  
Mixed Oxide Catalysts

The selective catalytic reduction of NOx (deNOx) at temperatures less than or at 200 °C was investigated while using C2H4 as the reductant and mixed oxides of Fe and Mn supported on activated carbon; their activity was compared to that of MnOx and FeOx separately supported on activated carbon. The bimetallic oxide compositions maintained high NO conversion of greater than 80–98% for periods that were three times greater than those of the supported monometallic oxides. To examine potential reasons for the significant increases in activity maintenance, and subsequent deactivation, the catalysts were examined by using bulk and surface sensitive analytical techniques before and after catalyst testing. No significant changes in Brunauer-Emmett-Teller (BET) surface areas or porosities were observed between freshly-prepared and tested catalysts whereas segregation of FeOx and MnOx species was readily observed in the mono-oxide catalysts after reaction testing that was not detected in the mixed oxide catalysts. Furthermore, x-ray diffraction and Raman spectroscopy data detected cubic Fe3Mn3O8 in both the freshly-prepared and reaction-tested mixed oxide catalysts that were more crystalline after testing. The presence of this compound, which is known to stabilize multivalent Fe species and to enhance oxygen transfer reactions, may be the reason for the high and relatively stable NO conversion activity, and its increased crystallinity during longer-term testing may also decrease surface availability of the active sites responsible for NO conversion. These results point to a potential of further enhancing catalyst stability and activity for low temperature deNOx that is applicable to advanced SCR processing with lower costs and less deleterious side effects to processing equipment.

Regeneration of field-spent activated carbon catalysts for low-temperature selective catalytic reduction of NOx with NH3

2011 ◽  
Vol 174 (1) ◽  
pp. 242-248 ◽  
Author(s):  
Jong-Ki Jeon ◽  
Hyeonjoo Kim ◽  
Young-Kwon Park ◽  
Charles H.F. Peden ◽  
Do Heui Kim
Keyword(s):  
Activated Carbon ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Reduction Of Nox ◽  
Carbon Catalysts

The DeNOx Characteristics of V/Ti Plate SCR Catalysts

2011 ◽  
Vol 356-360 ◽  
pp. 1712-1715
Author(s):  
Qiang Lu ◽  
Shu Hua Su ◽  
Shi Ye Fen ◽  
Wei Liang Cheng ◽  
Chang Qing Dong
Keyword(s):  
Nitric Oxide ◽  
Catalytic Activity ◽  
Selective Catalytic Reduction ◽  
Flue Gas ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Negative Effects ◽  
V2o5 Content ◽  
Scr Catalysts

A series of V2O5/WO3/TiO2plate catalysts were prepared via the incipient wetness impregnation method, with the V2O5content of 0.68 wt%, 1.01 wt%, 1.19 wt%, 1.5 wt% and the WO3loading of 4.8 wt%, 6.2 wt%, 7.9 wt%, 9.2 wt%, respectively. Selective catalytic reduction of nitric oxide by ammonia (NH3-SCR) experiments were performed to investigate the effects of the several factors on the performance of the catalysts, including the V2O5, WO3and MoO3content in the catalysts and the O2concentration in the flue gas. The results indicated that as the rising of the V2O5 content, the SCR activity of the V2O5/WO3/TiO2catalysts was firstly increased and then slightly decreased, with the best activity obtained at the V2O5content of 1.19 wt%. As the increasing of the WO3content, the activity was firstly increased slightly and then almost kept constant. Furthermore, the loading of the MoO3on the V2O5/WO3/TiO2plate catalysts would bring negative effects to the catalytic activity. In addition, the capability of the catalysts would slightly increase as the O2concentration rising up to 7%, and then became stable at higher O2concentrations.

High-temperature vanadium free catalyst for selective catalytic reduction of NO with NH3 and theoretical study of La2O3 over CeO2/TiO2

2021 ◽  
Author(s):  
Na Wang ◽  
Changfei Ye ◽  
Hui-Dong Xie ◽  
Lei Wang ◽  
Bin Zheng ◽  
...  
Keyword(s):  
High Temperature ◽  
Selective Catalytic Reduction ◽  
Theoretical Study ◽  
Catalytic Reduction ◽  
Impregnation Method ◽  
Scr Catalyst ◽  
Reduction Of No ◽  
No Conversion

High-temperature SCR catalyst of La2O3-CeO2/TiO2 was prepared by an impregnation method. The effect of CeO2 and La2O3 content on the NO conversion was studied and the experiment result showed that...

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