基于Aspen Plus的燃煤电厂烟气污染控制单元模拟
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摘要
采用Aspen Plus软件对烟气污染控制单元进行模拟,以电厂实际运行数据验证模型的正确性,建模过程中考虑SO_3转化和烟气中烟尘浓度的变化,并通过影响因素分析考察操作参数对污染物脱除效果的影响。结果表明,在选择性催化还原(SCR)脱硝过程中,部分SO2转化为SO_3,除尘过程中飞灰对SO_3有吸附作用,脱硫塔与除尘器对SO_3和灰分脱除具有协同作用;SCR脱硝过程的最佳氨氮摩尔比范围为0.8～1.0,氨氮比低于0.6、反应温度低于400℃时,SO_3浓度呈上升趋势;湿法脱硫过程中,入口烟气温度上升会阻碍SO2吸收和SO_3去除;湿式除尘过程中,除尘效率随温度升高而降低,随气体流速增加先升高后降低,最佳流速为0.8～1.2 m/s。
The Aspen Plus software was used to simulate the flue gas pollution control units and the correctness of the model was verified using the actual operation data of one power plant. In the modeling process, in addition to the removal of conventional flue gas pollutants, the SO_3 conversion and the change of dust concentration in the flue gas were taken into account. Furthermore, the effects of operating parameters on the pollutants removal efficiency were examined through influencing factors analysis. In this simulation model, the flue gas entered the SCR(Selective Catalytic Reduction) de-nitrification device firstly, followed by electrostatic precipitator, limestone-gypsum desulfurization, and finally went through the wet electrostatic precipitator process,achieving the ultra-low emission standards before discharges into the atmosphere. In the SCR denitration process, SO2 was oxidized to SO_3 due to the catalyst. Ash had an adsorption effect on SO_3 during the ESP(Eletrostatic Precipitator) process, and the desulfurization tower and the wet electrostatic precipitator process had a synergistic removal effect on SO_3 and ash. To accurate the simulation results, all these details mentioned above were simulated in this study. The influencing factors analysis showed that when the molar ratio of ammonia to nitrogen was lower than 0.6 and the reaction temperature was lower than 400℃, the concentration of SO_3 tended to rise. With the increase of the molar ratio of ammonia to nitrogen and temperature, part of SO_3 would react with excess ammonia forming NH4 HSO4 during the de-nitrification process, which could in turn caused blockage of the air pre-heater. Comprehensive analysis showed that the optimal ammonia-nitrogen molar ratio was in the range of 0.8～1.0. During the desulfurization process, the increase of the absorption liquid flux and the decrease of the inlet flue gas temperature were favorable for the removal of SO_3. During the wet dust removal process, when the flow rate of the flue gas was in the range of 0.8～1.2 m/s, the removal of soot was facilitated.
The Aspen Plus software was used to simulate the flue gas pollution control units and the correctness of the model was verified using the actual operation data of one power plant. In the modeling process, in addition to the removal of conventional flue gas pollutants, the SO_3 conversion and the change of dust concentration in the flue gas were taken into account. Furthermore, the effects of operating parameters on the pollutants removal efficiency were examined through influencing factors analysis. In this simulation model, the flue gas entered the SCR(Selective Catalytic Reduction) de-nitrification device firstly, followed by electrostatic precipitator, limestone-gypsum desulfurization, and finally went through the wet electrostatic precipitator process,achieving the ultra-low emission standards before discharges into the atmosphere. In the SCR denitration process, SO2 was oxidized to SO_3 due to the catalyst. Ash had an adsorption effect on SO_3 during the ESP(Eletrostatic Precipitator) process, and the desulfurization tower and the wet electrostatic precipitator process had a synergistic removal effect on SO_3 and ash. To accurate the simulation results, all these details mentioned above were simulated in this study. The influencing factors analysis showed that when the molar ratio of ammonia to nitrogen was lower than 0.6 and the reaction temperature was lower than 400℃, the concentration of SO_3 tended to rise. With the increase of the molar ratio of ammonia to nitrogen and temperature, part of SO_3 would react with excess ammonia forming NH4 HSO4 during the de-nitrification process, which could in turn caused blockage of the air pre-heater. Comprehensive analysis showed that the optimal ammonia-nitrogen molar ratio was in the range of 0.8～1.0. During the desulfurization process, the increase of the absorption liquid flux and the decrease of the inlet flue gas temperature were favorable for the removal of SO_3. During the wet dust removal process, when the flow rate of the flue gas was in the range of 0.8～1.2 m/s, the removal of soot was facilitated.
引文
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[7]孙志翱,金保升,李勇,等.基于Aspen Plus软件的湿法烟气脱硫模型[J].洁净煤技术,2006,12(3):82-85.Sun Z A,Jin B S,Li Y,et al.Wet flue gas desulfurization model based on Aspen Plus[J].Clean Coal Technology,2006,12(3):82-85.
[8]王向锋.烟气脱硫强化剂的作用及机理研究[D].杭州:浙江大学,2011:33-46.Wang X F.Effects and mechanisms of flue gas desulphurization with enhancers[D].Hangzhou:Zhejiang University,2011:33-46.
[9]Warych J,Szymanowski M.Optimum values of process parameters of the“wet limestone flue gas desulfurization system”[J].Chemical Engineering&Technology,2015,25(4):427-432.
[10]张文彪.大型化工模拟软件在工业气体处理工艺设计中的应用[D].北京:北京化工大学,2010:31-45.Zhang W B.Large chemical simulation software's usage in limestone wet FGD technology design[D].Beijing:Beijing University of Chemical Technology,2010:31-45.
[11]Cimini S,Prisciandaro M,Barba D.Simulation of a waste incineration process with flue-gas cleaning and heat recovery sections using Aspen Plus[J].Waste Management,2005,25(2):171-175.
[12]赵纪光,李焱,陶文亮.基于Aspen Plus的活性焦干法烟气脱硝过程模拟[J].广州化工,2014,42(2):30-34.Zhao J G,Li Y,Tao W L.Simulation of flue gas denitrification process by active coke using Aspen Plus[J].Guangzhou Chemical Industry,2014,42(2):30-34.
[13]杨玮,孙彬彬,王雪,等.山西某电厂燃煤烟气SO3与颗粒物排放特征[J].环境工程,2018,(1):83-87.Yang W,Sun B B,Wang X,et al.Emissions in coal-fired flue gas characteristics of SO3 and particulate from shanxi power plant[J].Environmmrntal Engineering,2018,(1):83-87.
[14]Hu Y,Yan J.Characterization of flue gas in oxy-coal combustion processes for CO2 capture[J].Applied Energy,2012,90(1):113-121.
[15]张卫宝,王广慧.影响选择性催化还原(SCR)法脱硝效率的因素分析[J].中国高新技术企业,2013,(30):84-86.Zhang W B,Wang G H.Effect of selective catalytic reduction(SCR)on denitrification efficiency[J].China High Technology Enterprises,2013,(30):84-86.
[16]张兴法,阮翔.湿法烟气脱硫系统脱硫效率影响因素分析[J].能源环境保护,2010,24(3):41-44.Zhang X F,Ruan X.Analysis of factors affecting desulfurization efficiency of wet flue gas desulfurization system[J].Energy Environmental Protection,2010,24(3):41-44.
[17]潘丹萍,吴昊,黄荣廷,等.石灰石-石膏法烟气脱硫过程中SO3酸雾脱除特性[J].东南大学学报(自然科学版),2016,46(2):311-316.Pan D P,Wu H,Huang R T,et al.Removal properties of sulfuric acid mist during limestone-gypsum flue gas desulfurization process[J].Journal of Southeast University(Natural Science Edition),2016,46(2):311-316.
[18]高建兵.湿式电除尘器的主要影响因素[J].维纶通讯,2009,(2):22-25.Gao J B.The main influencing factors of wet electrostatic precipitators[J].Whalen Communication,2009,(2):22-25.
[2]李壮壮.焦炉烟气高效氧化吸收脱硫脱硝一体化中试实验及模拟优化[D].济南:济南大学,2016:39-48.Li Z Z.Highly effective oxidation-absorption pilot experiments and simulation optimization of integrated desulfurization for coking flue gas[D].Jinan:Jinan University,2016:39-48.
[3]罗国华,米田绫子,加藤邦夫,等.气-固-固流化床用于燃煤电厂尾气同时脱硫脱硝[J].过程工程学报,2001,1(4):416-421.Luo G H,Yoneda A,Kato K,et al.A dry process for simultaneous removal of SO2 and NO from flue gas of power plants by using a gas-solid-solid fluidized bed[J].The Chinese Journal of Process Engineering,2001,1(4):416-421.
[4]任洪运,杨承,马晓茜.联合循环电站余热锅炉全工况烟气脱硝运行分析[J].广东电力,2016,29(7):29-34.Ren H Y,Yang C,Ma X X.Analysis on flue gas denitration operation of heat recovery boiler under full conditions in gas-steam combined cycle power station[J].Guangdong Electric Power,2016,29(7):29-34.
[5]陈茂兵,孙克勤.Aspen Plus软件在氨法烟气脱硫模拟中的应用[J].电力科技与环保,2009,25(4):30-32.Chen M B,Sun K Q.The application of Aspen Plus software on the simulation of FGD by ammonia[J].Electric Power Technology and Environmental Protect,2009,25(4):30-32.
[6]洪文鹏,何慧颖,刘广林,等.基于Aspen Plus的氨法脱硫单塔系统流程模拟[J].动力工程学报,2013,33(2):141-146.Hong W P,He H Y,Liu G L,et al.Numerical simulation on single-tower process of ammonia desulfurization system based on Aspen Plus[J].Journal of Chinese Society of Power Engineering,2013,33(2):141-146.
[7]孙志翱,金保升,李勇,等.基于Aspen Plus软件的湿法烟气脱硫模型[J].洁净煤技术,2006,12(3):82-85.Sun Z A,Jin B S,Li Y,et al.Wet flue gas desulfurization model based on Aspen Plus[J].Clean Coal Technology,2006,12(3):82-85.
[8]王向锋.烟气脱硫强化剂的作用及机理研究[D].杭州:浙江大学,2011:33-46.Wang X F.Effects and mechanisms of flue gas desulphurization with enhancers[D].Hangzhou:Zhejiang University,2011:33-46.
[9]Warych J,Szymanowski M.Optimum values of process parameters of the“wet limestone flue gas desulfurization system”[J].Chemical Engineering&Technology,2015,25(4):427-432.
[10]张文彪.大型化工模拟软件在工业气体处理工艺设计中的应用[D].北京:北京化工大学,2010:31-45.Zhang W B.Large chemical simulation software's usage in limestone wet FGD technology design[D].Beijing:Beijing University of Chemical Technology,2010:31-45.
[11]Cimini S,Prisciandaro M,Barba D.Simulation of a waste incineration process with flue-gas cleaning and heat recovery sections using Aspen Plus[J].Waste Management,2005,25(2):171-175.
[12]赵纪光,李焱,陶文亮.基于Aspen Plus的活性焦干法烟气脱硝过程模拟[J].广州化工,2014,42(2):30-34.Zhao J G,Li Y,Tao W L.Simulation of flue gas denitrification process by active coke using Aspen Plus[J].Guangzhou Chemical Industry,2014,42(2):30-34.
[13]杨玮,孙彬彬,王雪,等.山西某电厂燃煤烟气SO3与颗粒物排放特征[J].环境工程,2018,(1):83-87.Yang W,Sun B B,Wang X,et al.Emissions in coal-fired flue gas characteristics of SO3 and particulate from shanxi power plant[J].Environmmrntal Engineering,2018,(1):83-87.
[14]Hu Y,Yan J.Characterization of flue gas in oxy-coal combustion processes for CO2 capture[J].Applied Energy,2012,90(1):113-121.
[15]张卫宝,王广慧.影响选择性催化还原(SCR)法脱硝效率的因素分析[J].中国高新技术企业,2013,(30):84-86.Zhang W B,Wang G H.Effect of selective catalytic reduction(SCR)on denitrification efficiency[J].China High Technology Enterprises,2013,(30):84-86.
[16]张兴法,阮翔.湿法烟气脱硫系统脱硫效率影响因素分析[J].能源环境保护,2010,24(3):41-44.Zhang X F,Ruan X.Analysis of factors affecting desulfurization efficiency of wet flue gas desulfurization system[J].Energy Environmental Protection,2010,24(3):41-44.
[17]潘丹萍,吴昊,黄荣廷,等.石灰石-石膏法烟气脱硫过程中SO3酸雾脱除特性[J].东南大学学报(自然科学版),2016,46(2):311-316.Pan D P,Wu H,Huang R T,et al.Removal properties of sulfuric acid mist during limestone-gypsum flue gas desulfurization process[J].Journal of Southeast University(Natural Science Edition),2016,46(2):311-316.
[18]高建兵.湿式电除尘器的主要影响因素[J].维纶通讯,2009,(2):22-25.Gao J B.The main influencing factors of wet electrostatic precipitators[J].Whalen Communication,2009,(2):22-25.