氨法烟气脱硫SO_2吸收传质系数研究
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摘要
喷淋塔氨法脱硫技术被广泛应用于净化烟气的SO_2,传质系数是喷淋吸收塔重要的设计和运行参数,但目前文献中有关氨法脱硫传质系数的报道很少,还有待进一步研究。在喷淋塔中对氨法脱硫SO_2吸收传质过程进行了实验研究,结合对液滴和塔壁液膜运动的计算,得到不同实验条件下SO_2的吸收传质速率,并建立了氨法脱硫SO_2吸收传质系数表达式。该传质系数包含浆液pH、烟气流速ug和液气比L/G等主要参数,能够反映不同pH、ug和L/G条件下SO_2在单位气液接触面积上的传质速率。对比验证结果表明,该传质系数计算得到的SO_2吸收传质速率与实验值之间的相对误差小于±12%,二者能够较好地吻合。建立的传质系数表达式能够为喷淋塔氨法脱硫的优化设计和运行提供理论参考。
The ammonia-based flue gas desulfurization(FGD) using spray scrubber is widely used for removing SO_2 from flue gas. However, the reports about mass transfer coefficient of SO_2 in the ammonia-based desulphurization process are little in the literature and a further investigation is needed, even though the mass transfer coefficient of SO_2 is much needed for optimizing the design and operation of the absorption tower of ammonia-based FGD system.On basis of experiments of absorbing SO_2 with ammonia in a lab-scale spray scrubber, the mass transfer rate per unit gas-liquid interfacial area was investigated by calculating the motion of droplets and liquid membrane. The correlation to predict the mass transfer coefficient of SO_2 absorption by ammonia was also proposed, including parameters pH, ugand L/G. The yielding correlation could be used for quantitatively predicting the mass transfer rate per unit gas-liquid interfacial area under different operating conditions such as pH, gas flow rate and liquid-togas ratio. The comparison results show that the calculated SO_2 mass transfer rate agrees well with the measured data.The relative error between the calculated mass transfer rate and the measured data is within ±12%. The established mass transfer coefficient expression can provide a theoretical reference for the optimal design and operation of spray tower ammonia desulfurization.
The ammonia-based flue gas desulfurization(FGD) using spray scrubber is widely used for removing SO_2 from flue gas. However, the reports about mass transfer coefficient of SO_2 in the ammonia-based desulphurization process are little in the literature and a further investigation is needed, even though the mass transfer coefficient of SO_2 is much needed for optimizing the design and operation of the absorption tower of ammonia-based FGD system.On basis of experiments of absorbing SO_2 with ammonia in a lab-scale spray scrubber, the mass transfer rate per unit gas-liquid interfacial area was investigated by calculating the motion of droplets and liquid membrane. The correlation to predict the mass transfer coefficient of SO_2 absorption by ammonia was also proposed, including parameters pH, ugand L/G. The yielding correlation could be used for quantitatively predicting the mass transfer rate per unit gas-liquid interfacial area under different operating conditions such as pH, gas flow rate and liquid-togas ratio. The comparison results show that the calculated SO_2 mass transfer rate agrees well with the measured data.The relative error between the calculated mass transfer rate and the measured data is within ±12%. The established mass transfer coefficient expression can provide a theoretical reference for the optimal design and operation of spray tower ammonia desulfurization.
引文
[1]周理明,史永永,李海洋,等.氨法烟气脱硫过程的工艺优化[J].化学工程, 2014, 42(4):7-12.Zhou L M, Shi Y Y, Li H Y, et al. Process optimization of ammonia process flue gas desulfurization process[J]. Chemical Engineering, 2014, 42(4):7-12.
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[3] Gao H, Li C, Zeng G, et al. Flue gas desulphurization based on limestone-gypsum with a novel wet-type PCF device[J].Separation and Purification Technology, 2011, 76(3):253-260.
[4]李锦时,朱卫兵,周金哲,等.喷雾干燥半干法烟气脱硫效率主要影响因素的实验研究[J].化工学报, 2014, 65(2):724-730.Li J S, Zhu W B, Zhou J Z, et al. Experimental study on main influencing factors of spray drying semi-dry flue gas desulfurization efficiency[J]. CIESC Journal, 2014, 65(2):724-730.
[5]蔡毅,程乐鸣,许霖杰,等.循环流化床锅炉组合脱硫系统运行策略研究[J].中国电机工程学报, 2017,(1):161-172.Cai Y, Cheng L M, Xu L J, et al. Research on operation strategy of combined fluidized bed boiler combined desulfurization system[J].Proceedings of the CSEE, 2017,(1):161-172.
[6] Gao X, Ding H, Du Z, et al. Gas–liquid absorption reaction between(NH4)2SO3solution and SO2for ammonia-based wet flue gas desulfurization[J]. Applied Energy, 2010, 87(8):2647-2651.
[7] Jia Y, Zhong Q, Fan X, et al. Kinetics of oxidation of total sulfite in the ammonia-based wet flue gas desulfurization process[J].Chemical Engineering Journal, 2010, 164(1):132-138.
[8] Wang S J, Zhu P, Zhang G, et al. Numerical simulation research of flow field in ammonia-based wet flue gas desulfurization tower[J].Journal of the Energy Institute, 2015, 88(3):284-291.
[9] He B, Zheng X, Wen Y, et al. Temperature impact on SO2removal efficiency by ammonia gas scrubbing[J]. Energy Conversion&Management, 2003, 44(13):2175-2188.
[10] Long X L, Li W, Xiao W D, et al. Novel homogeneous catalyst system for the oxidation of concentrated ammonium sulfite[J].Journal of Hazardous Materials, 2006, 129(1/2/3):260.
[11] Jia Y, Yin L, Xu Y, et al. A model for performance of sulfite oxidation of ammonia-based flue gas desulfurization system[J].Atmospheric Pollution Research, 2015, 6(6):997-1003.
[12] Kaji R, Hishinuma Y, Kuroda H. SO2absorption by water droplets[J]. Journal of Chemical Engineering of Japan, 2006, 18(2):169-172.
[13] Javed K H, Mahmud T, Purba E. Enhancement of mass transfer in a spray tower using swirling gas flow[J]. Chemical Engineering Research&Design, 2006, 84(6):465-477.
[14] Yi Z, Xiang G, Wang H, et al. A model for performance optimization of wet flue gas desulfurization systems of power plants[J]. Fuel Processing Technology, 2008, 89(11):1025-1032.
[15]孙忠伟,周屈兰,惠世恩,等.气液双流程烟气脱硫塔内脱硫效率与传质性能的研究[J].热能动力工程, 2010,(3):326-329.Sun Z W, Zhou Q L, Hui S E, et al. Study on desulfurization efficiency and mass transfer performance in gas-liquid dual-flow flue gas desulfurization tower[J]. Thermal Power Engineering,2010,(3):326-329.
[16] Hu L, Wamg X, Yu G, et al. Study on gas–liquid phase mass transfer coefficient of entrained flow reactor[J]. Chemical Engineering Journal, 2008, 141(1/2/3):278-283.
[17] Marion M, Lepinasse E, Saboni A. SO2absorption and desorption by an accelerating water droplet undergoing vaporization[J].International Journal of Heat&Fluid Flow, 2006, 27(2):290-297.
[18] Hixson A W, Scott C E. Absorption of gases in spray towers[J].Ind. Eng. Chem., 1935, 27:307-314.
[19] Schmidt D I B, Stichlmair D I J. Two-phase flow and mass transfer in scrubbers[J]. Chemical Engineering&Technology,1991, 14(3):162-166.
[20] Codolo M C, Bizzo W A. Experimental study of the SO2, removal efficiency and volumetric mass transfer coefficients in a pilotscale multi-nozzle spray tower[J]. International Journal of Heat&Mass Transfer, 2013, 66(6):80-89.
[21] Bandyopadhay A, Biswas M N. Scrubbing of sulphur dioxide in a dual-flow scrubber[J]. J. India. Assoc. Environ. Manage, 1998,26:113-133.
[22] Colle S, Thomas D, Vanderschuren J. Process simulation of sulphur dioxide abatement with hydrogen peroxide solutions in a packed column[J]. Chemical Engineering Research&Design,2005, 83(1):81-87.
[23] Liu X, Guo Z, Roache N F, et al. Henry.s law constant and overallmass transfer coefficient for formaldehyde emission from smallwater pools under simulated indoor environmental conditions[J].Environmental Science&Technology, 2015, 49(3):1603-1610.
[24] Michalski J A. Aerodynamic characteristics of flue gasdesulfurization spray towers polydispersity consideration[J].Industrial&Engineering Chemistry Research, 2000, 39(9):3314-3324.
[25]戴干策,陈敏恒.化工流体力学[M].北京:化学工业出版社,1988.Dai G C, Chen M H. Chemical Engineering Fluid Mechanics[M].Beijing:Chemical Industry Press, 1988.
[26] Fogler H S. Elements of Chemical Reaction Engineering[M]. 4thed. Prentice-Hall PTR, 2006.
[27] Mounsef J R, Salameh D, Louka N, et al. The effect of aerationconditions, characterized by the volumetric mass transfercoefficient KLa, on the fermentation kinetics of Bacillus thuringiensis kurstaki[J]. Journal of Biotechnology, 2015, 210:100-106.
[28]刘敦禹, Terry Wall, Rohan Stanger.富氧燃烧烟气冷凝塔钠碱法脱硫过程SO2和CO2共同吸收建模与实验研究[J].化工学报, 2018, 69(9):4019-4029.Liu D Y, Wall T, Stanger R. Experimental and modelling study onco-absorption of SO2and CO2during desulfurization process byflue gas cooler for pxy-fuel combustion flues gas[J]. CIESCJournal, 2018, 69(9):4019-4029.
[29] Ma S, Zang B, Song H, et al. Research on mass transfer of CO2,absorption using ammonia solution in spray tower[J]. InternationalJournal of Heat&Mass Transfer, 2013, 67(12):696-703.
[2]黄荣廷,潘丹萍,盛溢,等.氨法烟气脱硫过程中气溶胶颗粒生成特性[J].化工学报, 2015, 66(11):4366-4372.Huang R T, Pan D P, Sheng Y, et al. Aerosol particle formation characteristics in ammonia flue gas desulfurization process[J].CIESC Journal, 2015, 66(11):4366-4372.
[3] Gao H, Li C, Zeng G, et al. Flue gas desulphurization based on limestone-gypsum with a novel wet-type PCF device[J].Separation and Purification Technology, 2011, 76(3):253-260.
[4]李锦时,朱卫兵,周金哲,等.喷雾干燥半干法烟气脱硫效率主要影响因素的实验研究[J].化工学报, 2014, 65(2):724-730.Li J S, Zhu W B, Zhou J Z, et al. Experimental study on main influencing factors of spray drying semi-dry flue gas desulfurization efficiency[J]. CIESC Journal, 2014, 65(2):724-730.
[5]蔡毅,程乐鸣,许霖杰,等.循环流化床锅炉组合脱硫系统运行策略研究[J].中国电机工程学报, 2017,(1):161-172.Cai Y, Cheng L M, Xu L J, et al. Research on operation strategy of combined fluidized bed boiler combined desulfurization system[J].Proceedings of the CSEE, 2017,(1):161-172.
[6] Gao X, Ding H, Du Z, et al. Gas–liquid absorption reaction between(NH4)2SO3solution and SO2for ammonia-based wet flue gas desulfurization[J]. Applied Energy, 2010, 87(8):2647-2651.
[7] Jia Y, Zhong Q, Fan X, et al. Kinetics of oxidation of total sulfite in the ammonia-based wet flue gas desulfurization process[J].Chemical Engineering Journal, 2010, 164(1):132-138.
[8] Wang S J, Zhu P, Zhang G, et al. Numerical simulation research of flow field in ammonia-based wet flue gas desulfurization tower[J].Journal of the Energy Institute, 2015, 88(3):284-291.
[9] He B, Zheng X, Wen Y, et al. Temperature impact on SO2removal efficiency by ammonia gas scrubbing[J]. Energy Conversion&Management, 2003, 44(13):2175-2188.
[10] Long X L, Li W, Xiao W D, et al. Novel homogeneous catalyst system for the oxidation of concentrated ammonium sulfite[J].Journal of Hazardous Materials, 2006, 129(1/2/3):260.
[11] Jia Y, Yin L, Xu Y, et al. A model for performance of sulfite oxidation of ammonia-based flue gas desulfurization system[J].Atmospheric Pollution Research, 2015, 6(6):997-1003.
[12] Kaji R, Hishinuma Y, Kuroda H. SO2absorption by water droplets[J]. Journal of Chemical Engineering of Japan, 2006, 18(2):169-172.
[13] Javed K H, Mahmud T, Purba E. Enhancement of mass transfer in a spray tower using swirling gas flow[J]. Chemical Engineering Research&Design, 2006, 84(6):465-477.
[14] Yi Z, Xiang G, Wang H, et al. A model for performance optimization of wet flue gas desulfurization systems of power plants[J]. Fuel Processing Technology, 2008, 89(11):1025-1032.
[15]孙忠伟,周屈兰,惠世恩,等.气液双流程烟气脱硫塔内脱硫效率与传质性能的研究[J].热能动力工程, 2010,(3):326-329.Sun Z W, Zhou Q L, Hui S E, et al. Study on desulfurization efficiency and mass transfer performance in gas-liquid dual-flow flue gas desulfurization tower[J]. Thermal Power Engineering,2010,(3):326-329.
[16] Hu L, Wamg X, Yu G, et al. Study on gas–liquid phase mass transfer coefficient of entrained flow reactor[J]. Chemical Engineering Journal, 2008, 141(1/2/3):278-283.
[17] Marion M, Lepinasse E, Saboni A. SO2absorption and desorption by an accelerating water droplet undergoing vaporization[J].International Journal of Heat&Fluid Flow, 2006, 27(2):290-297.
[18] Hixson A W, Scott C E. Absorption of gases in spray towers[J].Ind. Eng. Chem., 1935, 27:307-314.
[19] Schmidt D I B, Stichlmair D I J. Two-phase flow and mass transfer in scrubbers[J]. Chemical Engineering&Technology,1991, 14(3):162-166.
[20] Codolo M C, Bizzo W A. Experimental study of the SO2, removal efficiency and volumetric mass transfer coefficients in a pilotscale multi-nozzle spray tower[J]. International Journal of Heat&Mass Transfer, 2013, 66(6):80-89.
[21] Bandyopadhay A, Biswas M N. Scrubbing of sulphur dioxide in a dual-flow scrubber[J]. J. India. Assoc. Environ. Manage, 1998,26:113-133.
[22] Colle S, Thomas D, Vanderschuren J. Process simulation of sulphur dioxide abatement with hydrogen peroxide solutions in a packed column[J]. Chemical Engineering Research&Design,2005, 83(1):81-87.
[23] Liu X, Guo Z, Roache N F, et al. Henry.s law constant and overallmass transfer coefficient for formaldehyde emission from smallwater pools under simulated indoor environmental conditions[J].Environmental Science&Technology, 2015, 49(3):1603-1610.
[24] Michalski J A. Aerodynamic characteristics of flue gasdesulfurization spray towers polydispersity consideration[J].Industrial&Engineering Chemistry Research, 2000, 39(9):3314-3324.
[25]戴干策,陈敏恒.化工流体力学[M].北京:化学工业出版社,1988.Dai G C, Chen M H. Chemical Engineering Fluid Mechanics[M].Beijing:Chemical Industry Press, 1988.
[26] Fogler H S. Elements of Chemical Reaction Engineering[M]. 4thed. Prentice-Hall PTR, 2006.
[27] Mounsef J R, Salameh D, Louka N, et al. The effect of aerationconditions, characterized by the volumetric mass transfercoefficient KLa, on the fermentation kinetics of Bacillus thuringiensis kurstaki[J]. Journal of Biotechnology, 2015, 210:100-106.
[28]刘敦禹, Terry Wall, Rohan Stanger.富氧燃烧烟气冷凝塔钠碱法脱硫过程SO2和CO2共同吸收建模与实验研究[J].化工学报, 2018, 69(9):4019-4029.Liu D Y, Wall T, Stanger R. Experimental and modelling study onco-absorption of SO2and CO2during desulfurization process byflue gas cooler for pxy-fuel combustion flues gas[J]. CIESCJournal, 2018, 69(9):4019-4029.
[29] Ma S, Zang B, Song H, et al. Research on mass transfer of CO2,absorption using ammonia solution in spray tower[J]. InternationalJournal of Heat&Mass Transfer, 2013, 67(12):696-703.