Deposition and transformation characteristics of SCR by-product ammonium bisulfate on fly ash
LIU Shen1, LUO Zi-ying1, QING Meng-xia1, WANG Zhao-xi1, WANG Li-bang1, LIAO Yun-long1, HE Xiao-ling1, LIU Liang1, XIANG Jun2
1. School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China; 2. State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
Abstract:The blockage of the air preheater seriously affected the safe and economical operation of coal-fired power plants, which was often caused by the co-deposition of ammonium bisulfate (ABS) and fly ash. By simulating the temperature field in the air preheater, the deposition and transformation characteristics of ABS under the coexistence of fly ash were explored, which can provide guidance for the prevention and control of air preheater blockage. Fly ash had the capturing and adsorbing effects of the ABS generated in the flue gas, which increased the ABS deposition rate and the initial generation temperature. Under the conditions of 100 μL/L SO3 and 50μL/L NH3, the initial deposition temperature of ABS was between 240~270℃. There was no obvious ABS droplet in the high-temperature reaction basket, and the fly ash had an agglomeration phenomenon; a part of small droplets appeared on the wall of the reaction basket in the low-temperature stage, and the fly ash was in the form of large particles. ABS deposition would lead to the accumulation and adhesion of fly ash particles, which were converted to various sulfate salts with higher decomposition temperatures on the fly ash surface. Compared with the sulfate formed by the evolution of sulfuric acid droplets on the fly ash at low temperature, the sulfate formed by the conversion of ABS has a lower relative decomposition temperature.
刘燊, 罗子莹, 卿梦霞, 王朝曦, 王李邦, 廖云龙, 贺小玲, 刘亮, 向军. 脱硝副产物硫酸氢铵在飞灰表面沉积与演化特性[J]. 中国环境科学, 2022, 42(12): 5589-5597.
LIU Shen, LUO Zi-ying, QING Meng-xia, WANG Zhao-xi, WANG Li-bang, LIAO Yun-long, HE Xiao-ling, LIU Liang, XIANG Jun. Deposition and transformation characteristics of SCR by-product ammonium bisulfate on fly ash. CHINA ENVIRONMENTAL SCIENCECE, 2022, 42(12): 5589-5597.
Lu J Y, Zhou Z Y, Zhang H Z, et al. Influenced factors study and evaluation for SO2/SO3 conversion rate in SCR process[J]. Fuel, 2019,245:528-533.
[2]
方拓拓,高尔豪,王亮,等.1000MW燃煤电厂商业SCR脱硝催化剂的失活[J]. 中国环境科学, 2019,39(2):583-590. Fang T T, Gao E H, Wang L, et al. Deactivation of commercial SCR catalyst used in 1000MW coal-fired power plant[J]. China Environmental Science, 2019,39(2):583-590.
[3]
卿梦霞,刘亮,尹子骏,等.商用V/W/Ti系脱硝催化剂表面SO3生成的反应机理[J]. 中国环境科学, 2021,41(7):3161-3168. Qing M X, Liu L, Yi Z J, et al. Generation mechanism of SO3 on the surface of commercial V/W/Ti DeNOx catalysts[J]. China Environmental Science, 2021,41(7):3161-3168.
[4]
束航,张玉华,范红梅,等. SCR脱硝催化剂表面NH4HSO4生成及分解的原位红外研究[J]. 化工学报, 2015,66(11):4460-4468. Shu H, Zhang Y H, Fan H M, et al. FT-IR study of formation and decomposition of ammonium bisulfate on surface of SCR catalyst for nitrogen removal[J]. CIESC Journal, 2015,66(11):4460-4468.
[5]
Srivastava R K, Miller C A, Erickson C, et al. Emissions of Sulfur Trioxide from Coal-Fired Power Plants[J]. Journal of the Air & Waste Management Association, 2012,54(6):750-762.
[6]
马双忱,邓悦,吴文龙,等.SCR脱硝过程中硫酸氢铵形成特性实验研究[J]. 动力工程学报, 2016,36:143-149. Ma S C, Deng Y, WU W L, et al. Experimental research on ABS formation characteristics in SCR denitrification process[J]. Journal of Chinese Society of Power Engineering, 2016,36:143-149.
[7]
Guo K. Zhu Y X, Yan Z, et al. The dual effects of ammonium bisulfate on the selective catalytic reduction of NO with NH3 over Fe2O3-WO3 catalyst confined in MCM-41[J]. Chemical Engineering Journal, 2020,389:124271.
[8]
Zheng C Q, Cheng T, Yang L J, et al. Effect of SiO2 addition on NH4HSO4 decomposition and SO2 poisoning over V2O5-MoO3/TiO2- CeO2 catalyst[J]. Journal of Environmental Sciences, 2020,91:279-291.
[9]
王金玉,朱怀志,安泽文,等,Mn基脱硝催化剂抗水抗硫改性的模拟与实验研究[J]. 化工学报, 2019,70(12):4635-4644. Wang J Y, Zhu H Z, An Z W, et al. Simulation and experimental study on modification of water and sulfur resistance by Mn-based denitration catalyst[J]. CIESC Journal, 2019,70(12):4635-4644.
[10]
Yu R, Zhan Z C, Huang S J, et al. Cu-SSZ-13zeolite-metal oxide hybrid catalysts with enhanced SO2-tolerance in the NH3-SCR of NOx[J]. Applied Catalysis B:Environmental, 2020,269:118825.
[11]
刁润丽,赵世伟,刘嘉,烟气脱硝产生的硫酸氢铵对空预器的影响及对策[J]. 应用能源技术, 2015,(4):20-24. Dao R L, Zhao S W, Liu J, The effect of ammonium bisulfate in SCR flue gas denitrification process and solution for air preheater[J]. Applied Energy Technology, 2015,(4):20-24.
[12]
钟礼金,宋玉宝,锅炉SCR烟气脱硝空气预热器堵塞原因及其解决措施[J]. 热力发电, 2012,41(8):46-50. Zhong L J, Song Y B, Air preheater blocking in boiler with SCR denitrification device:reason analysis and solutions[J]. Thermal Power Generation, 2012,41(8):46-50.
[13]
卿梦霞,张鑫,刘亮,等.燃煤烟气脱硝副产物硫酸氢铵/硫酸铵沉积与分解特性研究[J]. 化工学报, 2020,72(2):1132-1141. Qing M X, Zhang X, Liu L, et al. Study on the deposition and decomposition characteristics of ammonium bisulfate/ammonium sulfate as the by-product of denitration in coal-fired flue gas[J]. CIESC Journal, 2020,72(2):1132-1141.
[14]
Qing M X, Lei S Y, Kong F H, et al. Analysis of ammonium bisulfate/sulfate generation and deposition characteristics as the by-product of SCR in coal-fired flue gas[J]. Fuel, 2022,313:122790.
[15]
Si F Q, Romero C E, Yao Z, et al. Inferential sensor for on-line monitoring of ammonium bisulfate formation temperature in coal-fired power plants[J]. Fuel Processing Technology, 2009,90(1):56-66.
[16]
Menasha J, Dunn-Rankin D, Muzio L, et al. Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater[J]. Fuel, 2011,90(7):2445-2453.
[17]
Zhang J K, Zhou H, Chen Z H, Experimental study on the ash deposit thermal conductivity for ammonium bisulfate and fly ash blend with an in situ measurement technology[J]. Fuel, 2020,263:116575.
[18]
马双忱,邓悦,吴文龙,等.SCR脱硝副产物硫酸氢铵与空预器中飞灰反应特性[J]. 环境工程学报, 2016,10:6563-6570. Ma S C, Deng Y, Wu W L, et al. Reaction characteristics of by-product ammonium bisulfate from SCR denitrification and fly ash in air preheater[J]. Chinese Journal of Environmental Engineering, 2016,10:6563-6570.
[19]
丁开瑞,马更生,郭玉安,某电厂600MW脱硝机组空气预热器堵塞处置措施[J]. 山西电力, 2016,(1):52-55. Ding K R, Ma G S, Guo Y, Treatment of air preheating clogging of a 600MW denitrification unit[J]. Shanxi Electric Power, 2016,(1):52-55.
[20]
Spörl R, Walkaer J, Belo L, et al. SO3 Emissions and Removal by Ash in Coal-Fired Oxy-Fuel Combustion[J]. Energy & Fuels, 2014, 28(8):5296-5306.
[21]
李小龙,李军状,段玖祥,等.燃煤电厂烟气中SO3协同控制情况及排放现状[J]. 中国电力, 2019,52(10):155-161. Li X L, Li J Z, Duan J X, et al. SO3 cooperative control and emission situation in the flue gas of coal-fired power plant[J]. Electric Power, 2019,52(10):155-161.
[22]
Zhou H, Zhang K J, Zhang K, Investigation of the deposition characteristics of ammonium bisulfate and fly ash blend using an on-line digital image technique:Effect of deposition surface temperature[J]. Fuel Processing Technology, 2018,179:359-368.
[23]
Wang X M, Du X S, Zhang L, et al. Promotion of NH4HSO4 decomposition in NO/NO2 contained atmosphere at low temperature over V2O5-WO3/TiO2 catalyst for NO reduction[J]. Applied Catalysis A:General, 2018,559:112-121.
[24]
Wang X M, Du X S, Liu S J, et al. Understanding the deposition and reaction mechanism of ammonium bisulfate on a vanadia SCR catalyst:A combined DFT and experimental study[J]. Applied Catalysis B:Environmental, 2020,260:118168.
[25]
Ye D, Qu R Y, Song H, et al. New insights into the various decomposition and reactivity behaviors of NH4HSO4 with NO on V2O5/TiO2 catalyst surfaces[J]. Chemical Engineering Journal, 2016, 283:846-854.
[26]
刘红玲,空气预热器腐蚀积灰问题探讨[J]. 能源研究与管理, 2019, (3):33-35. Liu H L. Discussion on corrosion and ash accumulation of air preheater[J]. Energy Research and Management, 2019,(3):33-35.
[27]
颜鲁,李秀财,孙奉仲,等.SCR脱硝伴生硫酸氢铵对飞灰颗粒特性影响的实验研究[J]. 中国电机工程学报, 2019,39(10):2987-2993. Yan L, Li X C, Sun F Z, et al. Experimental study on the effect of ammonium bisulfate on particle characteristics of fly ash during the SCR denitrification process[J]. Proceedings of the CSEE, 2019,39(10):2987-2993.
[28]
魏伟,李秀财,孙奉仲.超细飞灰对烟气酸露点与酸凝结的影响研究[J]. 化工学报, 2020,71(7):3258-3265. Wei W, Li X C, Sun F Z. Research on effect of ultrafine ash particles on acid dew point and acid condensation for coal-fired boilers[J]. CIESC Journal, 2020,71(7):3258-3265.
[29]
Ye D, Qu R Y, Song H, et al. Investigation of the promotion effect of WO3on the decomposition and reactivity of NH4HSO4 with NO on V2O5-WO3/TiO2SCR catalysts[J]. RSC Advance, 2016,6(60):55584-55592.
[30]
Zhang L, Li L L, Cao Y, et al. 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.
[31]
Ma Q X, Liu Y C, He H. Synergistic Effect between NO2 and SO2 in Their Adsorption and Reaction on γ-Alumina[J]. The Journal of Physical Chemistry A, 2008,112(29):6630-6635.