Promotion of NH4HSO4 decomposition in NO/NO2 contained atmosphere at low temperature over V2O5-WO3/TiO2 catalyst for NO reduction

Wang, Xiangmin; Du, Xuesen; Zhang, Li; Chen, Yanrong; Yang, Guangpeng; Ran, Jingyu

doi:10.1016/j.apcata.2018.04.025

Cited by 76 publications

(33 citation statements)

References 53 publications

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“…The results are in agreement with those in Reference [36]. Our previous works proposed that 1V5WTi catalyst covers all exposed TiO 2 surface sites [6,37]; both Lewis acid and Brønsted acid sites exist on the VWTi catalyst [38]. Both are also reduced by KCl and result in deactivation, while the number of weak acid sites was extremely enhanced (integral value of the peak area from 3318 to 11,984) through SO 2 -treatment, which certified the regeneration by SO 2 -treatment.…”

Section: Surface Acidity and Redox Propertiessupporting

confidence: 93%

“…Selective catalytic reduction (SCR), with high efficiency of NO x removal, is a wide-spread technology for reducing the emissions of NO x from the flue gas of power plants and the exhaust gas of vehicles [1][2][3][4]. NO x is reduced into harmless N 2 by NH 3 over catalysts, following Reactions (1)-(3) with different NO/NO 2 ratios [3,[5][6][7]:…”

Section: Introductionmentioning

confidence: 99%

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The Poisoning of V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2 SCR Catalysts by KCl and The Partial Regeneration by SO2

Nie

et al. 2020

Catalysts

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Poisoning effects by alkali metal chlorides is one of the major reasons for the deactivation of SCR catalyst in biomass-fired plants. In this study, the influence of KCl on two vanadium-based catalysts with different promoters, V 2 O 5 -WO 3 /TiO 2 and V 2 O 5 -Ce(SO 4 ) 2 /TiO 2 , was investigated. The catalytic activity of the fresh V 2 O 5 -WO 3 /TiO 2 was higher than that of V 2 O 5 -Ce(SO 4 ) 2 /TiO 2 at low temperatures. V 2 O 5 -Ce(SO 4 ) 2 /TiO 2 performed better than V 2 O 5 -WO 3 /TiO 2 when KCl was deposited on the catalyst surface. Both poisoned catalysts were efficiently regenerated by SO 2 treatment. The characterization results show that the reducibility and acidity of the catalysts were weakened by KCl deposition but regenerated by SO 2 .

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Section: Surface Acidity and Redox Propertiessupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

The Poisoning of V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2 SCR Catalysts by KCl and The Partial Regeneration by SO2

Nie

et al. 2020

Catalysts

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“…Moreover, the modified AC samples could achieve a maximum denitrification efficiency in >5 minutes. The removal of NO needs to be first adsorbed by AC and later reacted with NH 3 , and the introduction of transition metals can promote the adsorption of NO . The Ce exhibited the best denitrification activity, while V showed the lowest activity, since Ce has highest catalytic activity at the low temperature of 150°C and the optimum reaction temperature of V‐loaded AC is 220°C or higher …”

Section: Results and Disscussionmentioning

confidence: 99%

Enhancement of the denitrification efficiency over low‐rank activated coke by doping with transition metal oxides

Meng

Cheng

et al. 2020

Can J Chem Eng

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Low-rank activated coke (AC) is widely used for industrial flue gas purification due to its multipollutant cooperative removal capability. To enhance the denitrification capacity of AC for the selective catalytic reduction (SCR) of NO with NH 3 , several transition metal (Fe, Mn, Ce, V) oxides were uniformly loaded into AC by solvent impregnation. Compared to untreated AC, modified AC showed excellent denitrification efficiency above 90%. N 2 adsorptiondesorption and Raman spectroscopy techniques were used to characterize the pore size distribution and crystal structure of AC samples. The introduction of transition metal oxides had little effect on the pore structure of AC but increased the nitrogen-containing functional groups, which facilitated NO removal. Moreover, x-ray photoelectron spectroscopy (XPS) was used to analyze the valence changes of metal elements before and after denitrification.After the reaction, the content increase of the low-valence metal oxides indicated that the transition metal oxides were involved in the reaction of NO with NH 3 . High-valence metal oxides oxidized NO to NO 2 , which reacts more easily with NH 3 , thereby increasing the denitrification efficiency. Importantly, in the presence of SO 2 , modified AC still presented high denitrification performance.This transition metal oxides doping method can effectively improve the ability of low-rank AC to remove NO in multi-contaminant flue gas. K E Y W O R D Sactivated coke, denitrification, flue gas, SCR, transition metal oxides

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“…The flue gas temperature produced by part load is generally lower than 300 • C; under these conditions, the denitrification performance of the catalyst decreases on decreasing the temperature. Additionally, the SO 2 , SO 3 , and H 2 O in the flue gas react with NH 3 to produce ammonium bisulfate (ABS), which adsorbs into the micropores of the catalyst, and blocks the micropores of the catalyst, or bonds with fly ash to form large particles that cover the surface of the catalyst [3,4]. These phenomena cause catalyst deactivation, which decreases the efficiency of the SCR system; consequently, the system fails to meet its standard, or excess ammonia slip occurs [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Low-temperature performance of vanadium-based catalysts can be enhanced primarily by increasing the vanadium content. However, increasing V 2 O 5 content also increases the catalyst's ability to oxidize SO 2 under high temperatures, leading to increased formation of SO 3 and affecting downstream equipment. Moreover, ABS deposits remain on the catalyst surface, causing catalyst deactivation.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of the NH3-SCR Reactions over an Original and Sb-Modified V2O5–WO3/TiO2 Catalyst at Low Temperatures

et al. 2018

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Considering the practical requirements for continuous operation under part load condition, the commercial honeycomb selective catalytic reduction (SCR) catalyst was modified with Sb addition. Experiments were performed to investigate the effect of modification on long-time SCR performance under part load condition. Characterizations for the original and modified catalysts were also conducted to analyze the changes of the catalysts. The results indicated that the activity of modified catalyst was obviously enhanced in the temperature range of 275-325 • C and it achieved about 64.5% removal efficiency during the 30 h stability test at 275 • C. The characterization results indicated that the ammonium sulfate was chemically adsorbed on the catalyst surface at low temperatures, which led to the decrease of the specific surface area, pore volume, and V 4+ /V 5+ ratio of the catalysts. These are the reasons for the decrease of the catalyst activity at low temperatures, while the deposition amount of ammonium sulfate was relatively small over the modified catalyst. In addition, the decomposition temperature of the ammonium sulfate was reduced in the modified catalyst compared with the original one. NH 4 + ions decomposed at 275 • C by reacting with the NO x in the flue gas, and the dynamic equilibrium of this reaction was achieved on the modified catalyst after a short period of time. Therefore the modified catalyst can be continuously and stably operated at this temperature, and the part load operation of the SCR system in the coal-fired power plant can be realized.

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Promotion of NH4HSO4 decomposition in NO/NO2 contained atmosphere at low temperature over V2O5-WO3/TiO2 catalyst for NO reduction

Cited by 76 publications

References 53 publications

The Poisoning of V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2 SCR Catalysts by KCl and The Partial Regeneration by SO2

The Poisoning of V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2 SCR Catalysts by KCl and The Partial Regeneration by SO2

Enhancement of the denitrification efficiency over low‐rank activated coke by doping with transition metal oxides

A Comparative Study of the NH3-SCR Reactions over an Original and Sb-Modified V2O5–WO3/TiO2 Catalyst at Low Temperatures

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