600MW亚临界锅炉低NOx燃烧改造设计与数值模拟
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摘要
我国电力工业中燃煤火力发电占主导地位,但燃煤锅炉排放的大量氮氧化物(NOx)对生态环境造成了严重危害。国家最新出台的《火电厂大气污染物排放标准》对排放标准进行了严格限制。新的排放标准的及收费政策的出台使整个火电行业面临异常严峻的环保形势。采取措施减少氮氧化物的排放,是火电厂面临的一项刻不容缓的工作。
目前已有的控制常规燃煤电站锅炉NOx排放的技术措施可分为低NOx燃烧技术和烟气净化技术两类。尾部烟气脱硝技术投资及运行费用昂贵,而先进低NOx燃烧技术可降低排放浓度到450～650 mg/Nm3。对于烟煤可降低到450mg/Nm3以下,对已经投运600MW机组亚临界锅炉进行低NOx燃烧系统改造,目前还是一项空白。因此进行本课题的研究很有意义。
本论文通过对某600MW亚临界机组锅炉工程燃用煤种(神府东胜煤)和运行数据的分析,结合对已经运行锅炉的NOx排放数据进行分析,开发适合本改造工程的LNTFS低NOx的燃烧系统。本论文在改造设计方面的主要工作有:
1.改进的燃烧系统的设计;
2.改进的二次风配风方式的设计;
3.改进的一、二次风喷嘴的设计;
4.对锅炉NOx排放进行预测,并对运行调整提出建议。
在完成改造方案的基础上,通过数值模拟等方法验证此系统的减排效果及NOx排放数据;并通过数值模拟验证煤粉细度、风量分布等对锅炉性能指标的影响规律指导锅炉的运行。
Pulverized coal firing boilers account for mostly in our electric power industry, but the large amount of NOx emission from the pulverized coal firing boilers do great harm to our environment.To strictly limit the pollutant gas emission, our country have issued the emission standard for the pulverized coal firing power plant.The new standard and charging for the pollutant have put the pulverized coal firing plants into a servere environment protection situation. Great efforts have to be taken to reduce the NOx in most of the pulverized coal firing power plants.
At Present, there are two ways to decrease the NOx emission: the Low NOx Firing Technology and the Flue Gas Cleaning technology. Flue Gas Cleaning (SCR, i.e. selective catalytic reduction) are expensive to build and maintain comparing to the low NOx Firing Technology. Advanced low NOx firing technology can cut down the NOx concentration to 450-650mg/Nm3(O2=6%),450mg/Nm3 for bituminous coal.We have never rebuilt the low NOx firings system in the sub-critical unit ,so it is very meaningful to rebuilt the project.
By analyzing the designed coal (shenfu dongshen coal) of the 600MW sub-critical unit and the performance parameters of the project, this paper aim to exploit a LNCFS (Low NOx Concentric Firing System) which will be suitable to the project.The main tasks of the thesis are as follows:
Firstly: the design of the improved firing system;
Secondly: the design of the improved distributed mode of the secondary air;
Thirdly: the design of the improved primary and secondary air nozzle.
Fourthly: forcasting the NOx emission of the project and giving proposals for the coming operation of the unit.
On the basis of finishing the scheme of the project, numerical simulation is used to validate the amout of NOx ,And by the numerical simulation to test how the fineness of the coal,air distribution and other factors influence the performance of the boiler and then guide the operation of the boiler.
目前已有的控制常规燃煤电站锅炉NOx排放的技术措施可分为低NOx燃烧技术和烟气净化技术两类。尾部烟气脱硝技术投资及运行费用昂贵,而先进低NOx燃烧技术可降低排放浓度到450～650 mg/Nm3。对于烟煤可降低到450mg/Nm3以下,对已经投运600MW机组亚临界锅炉进行低NOx燃烧系统改造,目前还是一项空白。因此进行本课题的研究很有意义。
本论文通过对某600MW亚临界机组锅炉工程燃用煤种(神府东胜煤)和运行数据的分析,结合对已经运行锅炉的NOx排放数据进行分析,开发适合本改造工程的LNTFS低NOx的燃烧系统。本论文在改造设计方面的主要工作有:
1.改进的燃烧系统的设计;
2.改进的二次风配风方式的设计;
3.改进的一、二次风喷嘴的设计;
4.对锅炉NOx排放进行预测,并对运行调整提出建议。
在完成改造方案的基础上,通过数值模拟等方法验证此系统的减排效果及NOx排放数据;并通过数值模拟验证煤粉细度、风量分布等对锅炉性能指标的影响规律指导锅炉的运行。
Pulverized coal firing boilers account for mostly in our electric power industry, but the large amount of NOx emission from the pulverized coal firing boilers do great harm to our environment.To strictly limit the pollutant gas emission, our country have issued the emission standard for the pulverized coal firing power plant.The new standard and charging for the pollutant have put the pulverized coal firing plants into a servere environment protection situation. Great efforts have to be taken to reduce the NOx in most of the pulverized coal firing power plants.
At Present, there are two ways to decrease the NOx emission: the Low NOx Firing Technology and the Flue Gas Cleaning technology. Flue Gas Cleaning (SCR, i.e. selective catalytic reduction) are expensive to build and maintain comparing to the low NOx Firing Technology. Advanced low NOx firing technology can cut down the NOx concentration to 450-650mg/Nm3(O2=6%),450mg/Nm3 for bituminous coal.We have never rebuilt the low NOx firings system in the sub-critical unit ,so it is very meaningful to rebuilt the project.
By analyzing the designed coal (shenfu dongshen coal) of the 600MW sub-critical unit and the performance parameters of the project, this paper aim to exploit a LNCFS (Low NOx Concentric Firing System) which will be suitable to the project.The main tasks of the thesis are as follows:
Firstly: the design of the improved firing system;
Secondly: the design of the improved distributed mode of the secondary air;
Thirdly: the design of the improved primary and secondary air nozzle.
Fourthly: forcasting the NOx emission of the project and giving proposals for the coming operation of the unit.
On the basis of finishing the scheme of the project, numerical simulation is used to validate the amout of NOx ,And by the numerical simulation to test how the fineness of the coal,air distribution and other factors influence the performance of the boiler and then guide the operation of the boiler.
引文
[1]孙孝仁,孙怡玲.2020年世界能源前景.科技情报开发与经济,2000,10(2):15～16
[2]国家环境保护总局,火电厂大气污染物排放标准GB13233-2003,2003;
[3]赵惠富.污染气体NOx的形成和控制.北京:科学出版社,1993
[4]燃煤电站锅炉氮氧化物排放控制方法与改造方案的研究[R] , 2006
[5]余岳溪、邓剑华某电厂3号炉性能鉴定试验报告[R] 2006
[6]新井纪男.燃烧生成物的发生与抑制技术(赵黛青).北京:科学出版社,2001
[7].Song,Y.H,Nitric oxide formation during pulverized coal combustion.combustion science and technology,1982,28,p.31-39.
[8].Song,Y.H,oxidation and devolatilization of nitrogen in coal char,combustion science and technology,1982,28,p.177-183。
[9]章明川著电站锅炉燃烧理论基础[M] 2005
[10].Zeldovish,J.,the oxidation of nitrogen in combustion and explosion,acta physiochim.USSA,21,4,1964.
[11].Derek G,Gavin et al,Factors in the conversion of fuel nitrogen to nitric and nitrous oxides during fluidized bed combustion,Fuel 1993,72,381.
[12].Anker Jensen et al,formation and reduction of NOx in pressurized fluidized bed combustion of coal,Fuel 1995,74,1555.
[13].Marek A.wojtowicz et al,the fate of nitrogen functionalities in coal during pyrolysis and combustion,fuel 1995,74,507.
[14]范贤振、郭烈锦、高晖、聂剑平,670t/h四角切圆燃烧煤粉炉炉内过程的数值模拟,FLUENT第一届中国用户大会。
[15]崔成云、徐宝山、李永星、薛子畅,盘山电厂600MW电站锅炉炉内流场数值模拟计算研究,FLUENT第一届中国用户大会。
[16]曾汉才,大型锅炉高效低NOx燃烧技术的研究,锅炉制造,2003,3(1):1-11。
[17]朱彤、饶文涛、刘敏飞、张鹤声,低NOx高温空气燃烧技术,热能动力工程,2001,5(3):328-331。
[18].Shinji kamabara et.al,ralation between functional forms of coal nitrogen and emissions from pulverized coal combustion。Fuel,1995(74):(1247-1254)
[19]任建兴、翟晓敏、傅坚刚,火电厂氮氧化物的生成和控制,上海电力学院学报,2002(18):19-24。
[20].M.Xu,et al,modeling of the combustion process and NOx emission in a utility boiler,Fuel 2000,1611-1619.
[21].chungen yin et al,investigation of the flow,combustion,heat-transfer and emissions from a 609MW utility tangentially fired pulverized-coal boiler.Fuel 2002,997-1006.
[22].Shinji kamabara et.al,ralation between functional forms of coal nitrogen and emissions from pulverized coal combustion。Fuel,1995(74):(1247-1254)
[23].J.H.Pohl and A.F.Sarofim;16Symp(Int.)on combustion.P.491(1976)。
[24].D.W.Pershing and J.O.L Wendt,Ind.Eng.Chem.Process Des.Dev.,18,60(1979)。
[25]韩才元,徐明厚,周怀春,等.煤粉燃烧.北京:科学出版社,2001;
[26]束继伟,刘大俊.降低锅炉NOx排放的试验研究.黑龙江电力,2004,26(4):265~267
[27].Pohl.J .H and Sarofim. Devolatilization and oxidation of coal nitrogen. the Six teenthSymposium(International) on Combustion, 1977:491.
[28]上海锅炉厂引进技术文献2003
[29]张维侠、张建文LNCFS燃烧系统在600MW超临界机组中的应用[J] .锅炉技术2007/6,
[30]陈春元徐旭常等大型煤粉锅炉燃烧设备性能设计方法2002 ,219～220
[31]范卫东等上海锅炉厂有限公司和上海交通大学科研报告[R] 2008
[32] 1913t/h超临界压力直流锅炉(SG-1913/25.4-M951型)产品技术研究报告[R]2006
[33]钱力庚.330MW电站对冲锅炉炉内过程数值模拟和实验研究及四角锅炉变负荷研究炉内过程通用程序的设计与研究:[博士学位论文].杭州:浙江大学机械与能源工程学院,
[34]钱力庚,樊建人,孙平,等.600MW锅炉炉内流动与燃烧过程的数值模拟.动力工程,2001,21(1):1032～1037
[35]黄伟,曾汉才,朱全利,等.大型电站燃煤锅炉NOx生成的数值模拟.湖南电力,2001,21(1):1～4
[36]徐明厚,郑楚光.燃煤锅炉燃烧过程与NOx排放的模型与数值计算.工程热物理学报,2001,22(2):249～252
[37]郭印诚,林文漪,周力行.煤粉燃烧过程中NOx生成的数值模拟.燃烧科学与技术,1998,4(1):18～23
[38].R.K.Boyd and J.H.Kent.Three-Dimensional Furnace Computer Modelling.the 21st Symp.(Int.)on Combustion,1986,265～273
[39].Fortsch,Dieter.Kluger,Frank,et al.Klaus R.G.Kinetic model for the prediction NO emissions from staged combustion of pulverized coal.Symposium(International)on Combustion v 2 1998,12 oct 1998,3037～3044
[40].Cho,S.M.Conn,R.E.Seltzer,et al.Characteristics of char combustion in a high temperature advanced furnace for the power system.Proceedings of the International Technical Conference on Coal Utilization&Fuel Systems.Coal &Slurry Technology Assoc,Washington,DC,USA,1997,233～246
[41].izk,Tony,Fuller,R.Lee.Impact of secondary air distribution on NOx generation rate in large utility boiler.Industrial and Environmental Applications of Fluid Mechanics American Society of mechanical Engineers,Fluids Engineering Division(publication)FED v221,New York,NY USA,1995,63～73
[42].isona,S.P.Stan.3-D modeling of NOx formation in a 275MW utility boiler.Journal of the Institute of Energy,1996,69(479):68～79
[2]国家环境保护总局,火电厂大气污染物排放标准GB13233-2003,2003;
[3]赵惠富.污染气体NOx的形成和控制.北京:科学出版社,1993
[4]燃煤电站锅炉氮氧化物排放控制方法与改造方案的研究[R] , 2006
[5]余岳溪、邓剑华某电厂3号炉性能鉴定试验报告[R] 2006
[6]新井纪男.燃烧生成物的发生与抑制技术(赵黛青).北京:科学出版社,2001
[7].Song,Y.H,Nitric oxide formation during pulverized coal combustion.combustion science and technology,1982,28,p.31-39.
[8].Song,Y.H,oxidation and devolatilization of nitrogen in coal char,combustion science and technology,1982,28,p.177-183。
[9]章明川著电站锅炉燃烧理论基础[M] 2005
[10].Zeldovish,J.,the oxidation of nitrogen in combustion and explosion,acta physiochim.USSA,21,4,1964.
[11].Derek G,Gavin et al,Factors in the conversion of fuel nitrogen to nitric and nitrous oxides during fluidized bed combustion,Fuel 1993,72,381.
[12].Anker Jensen et al,formation and reduction of NOx in pressurized fluidized bed combustion of coal,Fuel 1995,74,1555.
[13].Marek A.wojtowicz et al,the fate of nitrogen functionalities in coal during pyrolysis and combustion,fuel 1995,74,507.
[14]范贤振、郭烈锦、高晖、聂剑平,670t/h四角切圆燃烧煤粉炉炉内过程的数值模拟,FLUENT第一届中国用户大会。
[15]崔成云、徐宝山、李永星、薛子畅,盘山电厂600MW电站锅炉炉内流场数值模拟计算研究,FLUENT第一届中国用户大会。
[16]曾汉才,大型锅炉高效低NOx燃烧技术的研究,锅炉制造,2003,3(1):1-11。
[17]朱彤、饶文涛、刘敏飞、张鹤声,低NOx高温空气燃烧技术,热能动力工程,2001,5(3):328-331。
[18].Shinji kamabara et.al,ralation between functional forms of coal nitrogen and emissions from pulverized coal combustion。Fuel,1995(74):(1247-1254)
[19]任建兴、翟晓敏、傅坚刚,火电厂氮氧化物的生成和控制,上海电力学院学报,2002(18):19-24。
[20].M.Xu,et al,modeling of the combustion process and NOx emission in a utility boiler,Fuel 2000,1611-1619.
[21].chungen yin et al,investigation of the flow,combustion,heat-transfer and emissions from a 609MW utility tangentially fired pulverized-coal boiler.Fuel 2002,997-1006.
[22].Shinji kamabara et.al,ralation between functional forms of coal nitrogen and emissions from pulverized coal combustion。Fuel,1995(74):(1247-1254)
[23].J.H.Pohl and A.F.Sarofim;16Symp(Int.)on combustion.P.491(1976)。
[24].D.W.Pershing and J.O.L Wendt,Ind.Eng.Chem.Process Des.Dev.,18,60(1979)。
[25]韩才元,徐明厚,周怀春,等.煤粉燃烧.北京:科学出版社,2001;
[26]束继伟,刘大俊.降低锅炉NOx排放的试验研究.黑龙江电力,2004,26(4):265~267
[27].Pohl.J .H and Sarofim. Devolatilization and oxidation of coal nitrogen. the Six teenthSymposium(International) on Combustion, 1977:491.
[28]上海锅炉厂引进技术文献2003
[29]张维侠、张建文LNCFS燃烧系统在600MW超临界机组中的应用[J] .锅炉技术2007/6,
[30]陈春元徐旭常等大型煤粉锅炉燃烧设备性能设计方法2002 ,219～220
[31]范卫东等上海锅炉厂有限公司和上海交通大学科研报告[R] 2008
[32] 1913t/h超临界压力直流锅炉(SG-1913/25.4-M951型)产品技术研究报告[R]2006
[33]钱力庚.330MW电站对冲锅炉炉内过程数值模拟和实验研究及四角锅炉变负荷研究炉内过程通用程序的设计与研究:[博士学位论文].杭州:浙江大学机械与能源工程学院,
[34]钱力庚,樊建人,孙平,等.600MW锅炉炉内流动与燃烧过程的数值模拟.动力工程,2001,21(1):1032～1037
[35]黄伟,曾汉才,朱全利,等.大型电站燃煤锅炉NOx生成的数值模拟.湖南电力,2001,21(1):1～4
[36]徐明厚,郑楚光.燃煤锅炉燃烧过程与NOx排放的模型与数值计算.工程热物理学报,2001,22(2):249～252
[37]郭印诚,林文漪,周力行.煤粉燃烧过程中NOx生成的数值模拟.燃烧科学与技术,1998,4(1):18～23
[38].R.K.Boyd and J.H.Kent.Three-Dimensional Furnace Computer Modelling.the 21st Symp.(Int.)on Combustion,1986,265～273
[39].Fortsch,Dieter.Kluger,Frank,et al.Klaus R.G.Kinetic model for the prediction NO emissions from staged combustion of pulverized coal.Symposium(International)on Combustion v 2 1998,12 oct 1998,3037～3044
[40].Cho,S.M.Conn,R.E.Seltzer,et al.Characteristics of char combustion in a high temperature advanced furnace for the power system.Proceedings of the International Technical Conference on Coal Utilization&Fuel Systems.Coal &Slurry Technology Assoc,Washington,DC,USA,1997,233～246
[41].izk,Tony,Fuller,R.Lee.Impact of secondary air distribution on NOx generation rate in large utility boiler.Industrial and Environmental Applications of Fluid Mechanics American Society of mechanical Engineers,Fluids Engineering Division(publication)FED v221,New York,NY USA,1995,63～73
[42].isona,S.P.Stan.3-D modeling of NOx formation in a 275MW utility boiler.Journal of the Institute of Energy,1996,69(479):68～79