FT-IR study of formation and decomposition of ammonium bisulfates on surface of SCR catalyst for nitrogen removal

doi:10.11949/j.issn.0438-1157.20150450

Abstract

Abstract:

The mechanism of ammonium bisulfate formation and decomposition over a commercial V₂O₅-WO₃/TiO₂ catalyst was explored using FT-IR. The results suggest that the formation of ammonium bisulfates mainly occurs in two ways: reaction between activated NH₃ adsorbed coordinatedly on Lewis acid sites of catalyst V═O groups and SO₂ under atmosphere containing O₂;and reaction between absorbed intermediate of metal sulfates VOSO₄ and gaseous NH₃. NO could react directly with NH₄⁺ in NH₄HSO₄, which could lower its decomposition temperature, promoting the catalytic decomposition of adsorbed bisulfates (ABS) on catalyst surface. So, there is mutual inhibition between NO removal and ABS formation. Loading of ABS deposited on catalyst surface also affects its decomposition and volatilization.

Key words: in situ FT-IR, selective catalytic reduction, catalyst, de-NO_x, NH₄HSO₄, chemical reaction

摘要：

采用工业用V₂O₅-WO₃/TiO₂催化剂,基于傅里叶原位红外光谱(in situ FT-IR)技术考察了SCR脱硝过程中催化剂表面NH₄HSO₄的生成与分解特性。结果表明:在V₂O₅-WO₃/TiO₂催化剂表面ABS的生成可由催化剂V═O基团上Lewis酸上配位吸附活化态的NH₃在O₂环境中与SO₂反应生成,也可由SO₂与催化剂表面反应生成的吸附态金属硫酸盐中间物VOSO₄与气态NH₃直接反应生成;NO能通过与NH₄HSO₄中的NH₄⁺直接反应来降低NH₄HSO₄降解的温度窗口,促进其在催化剂表面的分解行为,NO的脱除与NH₄HSO₄的生成是相互抑制关系;NH₄HSO₄本身的负载量影响其分解与挥发行为。

关键词: 原位红外光谱, 选择催化还原, 催化剂, 脱硝, NH₄HSO₄, 化学反应

CLC Number:

X511

SHU Hang, ZHANG Yuhua, FAN Hongmei, ZHANG Yaping, YANG Linjun. FT-IR study of formation and decomposition of ammonium bisulfates on surface of SCR catalyst for nitrogen removal[J]. CIESC Journal, 2015, 66(11): 4460-4468.

束航, 张玉华, 范红梅, 张亚平, 杨林军. SCR脱硝中催化剂表面NH₄HSO₄生成及分解的原位红外研究[J]. 化工学报, 2015, 66(11): 4460-4468.

References 28

[1]	Zhao Yufeng(赵宇峰), Zhao Bo(赵博), Zhuo Yuqun(禚玉群), Chen Changhe(陈昌和), Xu Xuchang(徐旭常). Influences of SO2 on the catalytic effect for selective catalytic reduction of NO by NH3 over iron-based sulfates [J]. Proceedings of the CSEE(中国电机工程学报), 2011, 31(23): 27-33.
[2]	Zhu Baoshan(朱宝山).The purificatory Technical Manual of Atmospheric Pollutants from Coal-fired Boilers(燃煤锅炉大气污染物净化技术手册) [M]. Beijing: China Electric Power Press, 2006: 5-10.
[3]	Wu Bijun (吴碧君), Liu Xiaoqin (刘晓勤), Xiao Ping (肖萍). Binary metal oxides supported on TiO2 for low-temperature selective catalytic reduction of NOx with NH3 [J]. Proceedings of the CSEE(中国电机工程学报), 2008, 28(23): 75-80.
[4]	Gao Yan (高岩), Luan Tao (栾涛), Peng Jiwei (彭吉伟), Lü Tao(吕涛). DeNOx performance of SCR catalyst for exhaust gas from coal-fired power plant [J]. CIESC Journal(化工学报), 2013, 64(7): 2611-2618.
[5]	Forzatti P, Nova I, Beretta A.Catalytic properties in deNOx and SO2-SO3 reactions [J]. Catalysis Today, 2000, 56: 431-441.
[6]	Shomate C H, Naylor B F.High-temperature heat contents of aluminum oxide, aluminum sulfate, potassium sulfate, ammonium sulfate and bisulfate sulfate [J]. Journal of the American Chemical Society, 1945, 67(1): 72-75.
[7]	Burke J M, Johnson K L.Ammonium Sulfate and Bisulfate Sulfate Formation in Air Preheaters[R].Washington: United States Environment Protection Agency, 1982.
[8]	Zheng Y, Jensen A D, Johnsson J E. Laboratory investigation of selective catalytic reduction catalysts: deactivation by potassium compounds and catalyst generation [J]. Industrial & Engineering Chemistry Research, 2004, 43(4): 941-947.
[9]	Chothani C.Ammonium Bisulfate(ABS) Measurement for SCR NOx Control and Air Heater Protection[R].Carnegie: Breen Energy Solution, 2008: 1-13.
[10]	Menasha J, Dunn-Rankin D, Muzio L, Stallings J. Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater [J]. Fuel, 2011, 90: 2445-2453.
[11]	Zhang Yuhua(张玉华), Shu Hang(束航), Fan Hongmei(范红梅), Zhang Yaping (张亚平), Yang Linjun (杨林军). Research on emission characteristics and influencing factors of PM2.5 for selective catalytic reduction based on V2O5-WO3/TiO2 commercial catalysts [J]. Proceedings of the CSEE(中国电机工程学报), 2015, 35(2): 383-389.
[12]	Benson S A, Laumb J D, Crocker C R. SCR catalyst performance in flue gases derived from subbituminous and lignite coals [J]. Fuel Processing Technology, 2005, 86(5): 577-613.
[13]	Sun D K, Liu Q Y, Liu Z Y, Gui G Q, Huang Z G.Adsorption and oxidation of NH3 over V2O5/AC surface [J]. Applied Catalysis B: Environmental, 2009, 92: 462-467.
[14]	Ramis G, Yi L, Busca G. Ammonia activation over catalysts for the selective catalytic reduction of NOx and the selective catalytic oxidation of NH3. An FT-IR study [J]. Catal. Today, 1996, 28(4):373.
[15]	Ito E, Mergler Y J, Nieuwenhuys B E.NOx reduction with ammonia over cerium exchanged mordenite in the presence of oxygen [J]. Studies in Surface Science and Catalysis, 1995, 98: 146-147.
[16]	Xu W Q, He H, Yu Y B.Deactivation of a Ce/TiO2 catalyst by SO2 in the selective catalytic reduction of NO by NH3 [J]. Journal of Physical Chemistry, 2009, 113: 4426-4432.
[17]	Zhang L, Li L L, Cao Y, Yao X J, Ge C Y, Gao F, Yu D, Tang C J, Dong L.Getting insight into the influence of SO2 on TiO2/CeO2 for the selective catalytic reduction of NO by NH3 [J]. Applied Catalysis B: Environmental, 2015, 165: 589-598.
[18]	Zhu Z P, Niu H X, Liu Z Y, Liu S J.Decomposition and reactivity of NH4HSO4 on V2O5/AC catalysts [J]. Journal of Catalysis, 2000, 195: 268-278.
[19]	Yang S J, Guo Y F, Chang H Z, Ma L, Peng Y, Qu Z, Yan N Q, Wang C Z, Li J H .Novel effect of SO2 on the SCR reaction over CeO2: mechanism and significance [J]. Applied Catalysis, 2013, 136: 19-28.
[20]	Long R Q, Yang R T. Selective catalytic reduction of nitrogen oxides by ammonia over Fe3+-exchanged TiO2-pillared clay catalysts [J]. Applied Catalysis B: Environmental, 2011, 103: 369-37.
[21]	Zhang L, Wang D, Liu Y, Kamasamudram K, Li J H, Epling W.SO2 poisoning impact on the NH3-SCR reaction over a commercial Cu-SAPO-34 SCR catalyst [J]. Applied Catalysis, 2014, 156: 371-377.
[22]	Ma J R, Liu Z Y, Liu Q Y, Guo S J, Huang Z G, Xiao Y.SO2 and NO removal from flue gas over V2O5/AC at lower temperatures-role of V2O5 on SO2 removal [J]. Fuel Processing Technology, 2008, 89: 242-248.
[23]	Guo X Y, Bartholomew C, Hecker W, Baxter L L.Effects of sulfate species on V2O5/TiO2 SCR catalysts in coal and biomass-fired systems [J]. Applied Catalysis B: Environmental, 2009, 92: 30-40.
[24]	Lapina O B, Bal'zhinimaev B S, Boghosian S, Eriksen K M, Fehrmann R.Progress on the mechanistic understanding of SO2 oxidation catalysts [J]. Catalysis Today, 1999, 51: 469-479.
[25]	Rasmussen S B, Eriksen K M, Fehrmann R. Sulfato complex formation of V(Ⅴ) and V(Ⅳ) in pyrosulfate melts investigated by potentiometry and spectroscopic methods [J]. Journal of Physical Chemistry B, 1999, 103: 11282-11289.
[26]	Yamaguchi T, Jin T, Tanabe K.Structural identification of acid sites of sulfur-promoted solid super acid and construction of its structure on silica support [J]. Phys. Chem., 1986, 90: 3148-4152.
[27]	Jin R B, Liu Y, Wu Z B, Wang H Q, Gu T T.Relationship between SO2 poisoning effects and reaction temperature for selective catalytic reduction of NO over Mn-Ce/TiO2 catalyst [J]. Journal of Catalysis Today, 2010, 153: 84-89.
[28]	Huang Z G, Zhu Z P, Liu Z Y, Liu Q Y.Formation and reaction of ammonium sulfate salts on V2O5/AC catalyst during selective catalytic reduction of nitric oxide by ammonia at low temperatures [J]. Journal of Catalysis, 2003, 214(2): 213-219.