On the promotion by SO2 of the SCR process over Ag/Al2O3: influence of SO2 concentration with C3H6 versus C3H8 as reductant

Angelidis, Thomas; Christoforou, Sophia C.; Bongiovanni, Alessandro; Kruse, Norbert

doi:10.1016/s0926-3373(02)00086-3

Cited by 39 publications

(27 citation statements)

References 14 publications

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“…About 3% increase in terms of NO conversion to N 2 in the reaction temperature range of 250$450°C was observed compared with the SO 2 -free conditions. The result obtained in the C 2 H 2 -SCR is consistent with that reported in the literature [22] regarding the presence of SO 2 in the C 3 H 6 -SCR and C 3 H 8 -SCR study.…”

Section: Tolerance Of the Ce-h-zsm-5 (25) To Sulfur Dioxidesupporting

confidence: 92%

The First Study of SCR of NOx by Acetylene in Excess Oxygen

Wang

et al. 2005

Catal Lett

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Acetylene as a reducing agent for the selective catalytic reduction (C 2 H 2 -SCR) of NO in the presence of excess oxygen on various Ce-exchanged zeolites was investigated for the first time. Under the conditions of 1600 ppm NO, 800 ppm C 2 H 2 , and 9.95 % O 2 in He, the Ce-H-ZSM-5 (Si/Al=25) catalyst shows about 83% NO conversion to N 2 at the temperatures ranged from 300 to 350°C. It is followed by the other zeolites in the activity order of Ce-H-Y (Si/Al=2.5), Ce-H-_ (Si/A1=20$30), and Ce-H-SAPO (Si/Al=34), Ce-H-5A (Si/Al=12). Almost no NO conversion was obtained over Ce-Na-ZSM-5 (Si/Al=25) and Na-ZSM-5 (Si/Al=25) catalyst samples. The Conversion of NO to N 2 increased with O 2 concentration in the range of 0.1 $ 9.95% over the CeH-ZSM-5 (Si/Al=25) catalyst. It is suggested that O 2 plays an important role in the C 2 H 2 -SCR of NO reaction, by oxidizing NO to NO 2 on acid sites in assistant with cerium species of the catalyst. A large amount of CO, which seems to be in proportion with the NO conversion to N 2 , was produced. Long-term experiments up to 56 h combined with a excursion of the reaction temperature up to 650°C over the Ce-H-ZSM-5 (Si/A1=25) confirmed the catalyst's durable performance under the reaction conditions. It is found that the de-NO x activity of Ce-H-ZSM-5 catalyst can be enhanced by the presence of 50 ppm of sulfur dioxide in the dry-feed reaction conditions.

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Section: Tolerance Of the Ce-h-zsm-5 (25) To Sulfur Dioxidesupporting

confidence: 92%

The First Study of SCR of NOx by Acetylene in Excess Oxygen

Wang

et al. 2005

Catal Lett

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“…As paraffin HC chain length increases and becomes unsaturated, so does NOx conversion, allowing the catalyst to become more active and reducing NOx emissions at lower temperatures [3], [13], [18]. As chain length and unsaturation increases, coke production and rate of coke deposition on the catalyst increases, limiting NOx reduction [3], [13], [15].…”

Section: Introductionmentioning

confidence: 99%

Enhancing selective catalytic reduction of NOx with alternative reactants/promoters

Herreros

George

Umar

et al. 2014

Chemical Engineering Journal

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The hydrocarbon-selective catalytic reduction (HC-SCR) activity of an Ag/Al 2 O 3 catalyst was investigated. The function on catalytic NOx reduction of different fuel properties using alternative reactants such as gas-to-liquid (GTL) and butanol was studied. This work proves that such improvements are due to the high reactivity, polarity and diffusivity of butanol within the catalyst enhancing NOx conversion. Furthermore, it is suggested that HC components such butanol share some of the reaction mechanisms to hydrogen as a promoter in addition to his role as a reductant leading to improve NOx reduction. Therefore, it is proposed the simultaneous dual role of butanol as a reactant and as promoter.Catalyst performance at low temperature was further improved with the addition of hydrogen (H 2 ).However, this performance was found to degrade as temperature increases, due to H 2 reactant selectivity changing, directly being oxidised. Increased NOx conversion was dependent on HC:NOx ratio, showing at low temperature a low HC:NOx ratio is required. As temperature increases, so does the required HC:NOx ratio to compensate for hydrocarbons partial and complete oxidation. These results demonstrate a method of gaining significant NOx reduction through the combination of environmental catalysts and alternative reactants.

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“…The CO ppm changes are mainly related to methane oxidation. This indicates that the methane activation may be influenced by the surface modification under SO 2 [20]. However, for Ag/Al 2 O 3 catalysts no changes in CO concentration values were found in the presence and absence of SO 2 .…”

Section: Activity Resultsmentioning

confidence: 89%

SO2 promoted alkali metal doped Ag/Al2O3 catalysts for CH4-SCR of NOx

Rao

2012

Applied Catalysis A: General

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On the promotion by SO2 of the SCR process over Ag/Al2O3: influence of SO2 concentration with C3H6 versus C3H8 as reductant

Cited by 39 publications

References 14 publications

The First Study of SCR of NOx by Acetylene in Excess Oxygen

The First Study of SCR of NOx by Acetylene in Excess Oxygen

Enhancing selective catalytic reduction of NOx with alternative reactants/promoters

SO2 promoted alkali metal doped Ag/Al2O3 catalysts for CH4-SCR of NOx

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