220 t/h煤粉锅炉臭氧氧化NO_x超低排放试验研究
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摘要
近年来,国家对于环境保护的要求愈发严苛,煤电行业节能减排任务愈加艰巨,燃煤电厂的超低排放改造工作迫在眉睫。笔者针对3台220 t/h煤粉锅炉NO_x进行臭氧脱硝改造和脱硝试验研究,采用烟气分析仪及电厂在线检测系统,探究了O_3/NO摩尔比及NO_x初始浓度等对脱硝效果的影响。试验结果表明,活性分子臭氧脱硝技术对该煤粉炉锅炉具有较好的脱硝效果,NO_x脱除效率可达90%以上。锅炉出口NO_x浓度随锅炉负荷波动较大,呈正相关关系,锅炉负荷升高,出口NO_x浓度升高;锅炉负荷降低,出口NO_x浓度随之降低。臭氧脱硝效率随O_3/NO摩尔比和臭氧投加量的增加而增大,但当O_3/NO摩尔比超过一定值后,其增大速率随臭氧量的增加而逐渐变缓。臭氧脱硝技术中脱硝效率受NO_x初始浓度的影响较小,O_3/NO摩尔比达到一定量时,可保证不同NO_x初始浓度波动下的脱硝效率。本试验获得的特性曲线为臭氧脱硝技术最佳臭氧喷射量的确定提供了依据,即在保证脱硝效率的前提下,如何选择最佳的O_3/NO摩尔比。应用臭氧脱硝技术后,该电厂顺利通过了168 h测试,烟气排放中NO_x浓度稳定在50 mg/Nm~3以下,满足国家超低排放要求,可见采用活性分子臭氧对烟气中的NO_x具有良好的脱除效果。
In recent years,the requirement of environmental protection has become more and more stringent,and the task of energy saving and emission reduction in coal-fired power industry has become more and more arduous.The transformation of ultra-low emission of coalfired power plants is imminent.In this paper,three 220 t/h pulverized coal fired boilers were revamped with ozone denitration technology,and a series of debugging tests were carried out.With the help of flue gas analyzer and on-line detection system of power plant,the effects of O_3/NO molar ratio and initial concentration of NO_xon denitration effect were mainly explored.The experimental results show that the application of ozone denitration technology in the pulverized coal boiler has a very good denitration effect,and the removal efficiency of NO_x reaches more than 90%.The NO_x concentration at the outlet of the boiler fluctuates greatly with the boiler load.The boiler load increases and the NO_xconcentration at the outlet increases.If the boiler load decreases,the NO_xconcentration at the outlet also decreases,showing a positive correlation.The efficiency of ozone denitration increases with the increase of the molar ratio of O_3/NO and ozone dosage,but when the molar ratio of O_3/NO exceeds a certain value,the rate of ozone denitration increases slowly with the increase of ozone dosage.In ozone denitration technology,the denitration efficiency is less affected by the initial concentration of NO_x.When the molar ratio of O_3/NO reaches a certain value,the denitration efficiency can be guaranteed under different conditions of the initial concentration fluctuation of NO_x.The characteristic curve obtained in this experiment provides a basis for determining the optimum ozone injection quantity in the application of ozone denitration technology,that is,how to select the optimum O_3/NO ratio on the premise of ensuring the denitration efficiency.After the application of ozone denitration technology,the power plant passed 168 hours of test successfully.The concentration of NO_xin flue gas emission is stable below 50 mg/Nm~3,which meets the national ultra-low emission requirements.It can be seen that the use of ozone denitration technology to control the emission of NO_xin flue gas has a very good effect.
In recent years,the requirement of environmental protection has become more and more stringent,and the task of energy saving and emission reduction in coal-fired power industry has become more and more arduous.The transformation of ultra-low emission of coalfired power plants is imminent.In this paper,three 220 t/h pulverized coal fired boilers were revamped with ozone denitration technology,and a series of debugging tests were carried out.With the help of flue gas analyzer and on-line detection system of power plant,the effects of O_3/NO molar ratio and initial concentration of NO_xon denitration effect were mainly explored.The experimental results show that the application of ozone denitration technology in the pulverized coal boiler has a very good denitration effect,and the removal efficiency of NO_x reaches more than 90%.The NO_x concentration at the outlet of the boiler fluctuates greatly with the boiler load.The boiler load increases and the NO_xconcentration at the outlet increases.If the boiler load decreases,the NO_xconcentration at the outlet also decreases,showing a positive correlation.The efficiency of ozone denitration increases with the increase of the molar ratio of O_3/NO and ozone dosage,but when the molar ratio of O_3/NO exceeds a certain value,the rate of ozone denitration increases slowly with the increase of ozone dosage.In ozone denitration technology,the denitration efficiency is less affected by the initial concentration of NO_x.When the molar ratio of O_3/NO reaches a certain value,the denitration efficiency can be guaranteed under different conditions of the initial concentration fluctuation of NO_x.The characteristic curve obtained in this experiment provides a basis for determining the optimum ozone injection quantity in the application of ozone denitration technology,that is,how to select the optimum O_3/NO ratio on the premise of ensuring the denitration efficiency.After the application of ozone denitration technology,the power plant passed 168 hours of test successfully.The concentration of NO_xin flue gas emission is stable below 50 mg/Nm~3,which meets the national ultra-low emission requirements.It can be seen that the use of ozone denitration technology to control the emission of NO_xin flue gas has a very good effect.
引文
[1]中国电力企业联合会.中国煤电清洁发展报告[EB/OL].[2017-09-22]. http://www. cec. org. cn/zhuanti/2017nianzhuanti/zhongguomeidianqingjiefazhanyuhuanjingyingxiangfabuyantaohui/meitibaodao/2017-09-22/173392.html.
[2]中华人民共和国环境保护部.全面实施燃煤电厂超低排放和节能改造工作方案[EB/OL].[2015-12-11]. http://power. inen.com/html/power-2249399.shtml.
[3]陈玉龙,王锐.关于锅炉脱硝改造后产生堵灰及腐蚀问题探讨[J].锅炉制造,2018(6):40-41.CHEN Yulong,WANG Rui. Discussion on blockage and corrosion of boiler after denitrification[J]. Boiler Manufacturing,2018(6):40-41.
[4]宫家宏.电站煤粉炉氮氧化物控制技术[J].电力设备管理,2018(10):84-88.GONG Jiahong. Nitrogen oxide control technology for pulverized coal fired boilers in power plants[J]. Electric Power Equipment Management,2018(10):84-88.
[5]STBERG M,DAM-JOHANSEN K.Empirical modeling of the selective non-catalytic reduction of no:Comparison with large-scale experiments and detailed kinetic modeling[J].Chemical Engineering Science,1994,49(12):1897-1904.
[6]王小娥.选择性非催化还原烟气脱硝技术在CFB锅炉及煤粉炉上的应用比较[D].上海:上海交通大学,2014.
[7]姜树栋.利用臭氧及活性分子协同脱除多种污染物的实验及机理研究[D].杭州:浙江大学,2010.
[8]王智化.燃煤多种污染物一体化协同脱除机理及反应射流直接数值模拟DNS的研究[D].杭州:浙江大学,2005.
[9]张建平,万凯迪,王荣涛,等.生物质循环流化床锅炉臭氧脱硝试验研究[J].环境工程技术学报,2019,9(1):8-13.ZHANG Jianping,WAN Kaidi,WANG Rongtao,et al.Experimental study on ozone denitration of a biomass circulating fluidized bed boiler[J].Journal of Environmental Engineering Technology,2019,9(1):8-13.
[10]朱燕群,杨业,黄建鹏,等.橡胶厂60 000 m3/h炭黑干燥炉烟气臭氧脱硝试验研究[J].浙江大学学报(工学版),2016,50(10):1865-1870.ZHU Yanqun,YANG Ye,HUANG Jianpeng,et al. Removal of NOxby ozone oxidation from flue gas of 60 000 m3/h carbon black drying furnace of rubber plant[J].Journal of Zhejiang University(Engineering Science),2016,50(10):1865-1870.
[11]马强.烟气中多种污染物超低排放的活性分子氧化及一体化脱除机理研究[D].杭州:浙江大学,2016.
[12] WANG Z H,ZHOU J H,ZHU Y Q,et al.Simultaneous removal of NOx,SO2and Hg in nitrogen flow in a narrow reactor by ozone injection:Experimental results[J]. Fuel Processing Technology,2007,88(8):817-823.
[13]国家市场监督管理总局.煤炭质量分级第1部分:灰分:GB/T 15224. 1—2018[S/OL].[2018-09-01]. http://www.gb688. cn/bzgk/gb/newGbInfo? hcno=0B7290DEB716BE83A82D1B5E86DAFC13.
[14]煤炭工业协会.煤炭质量分级第2部分:硫分:GB/T 15224.2—2010[S/OL].[2010-09-26]. http://www. zbgb. org/2/StandardDetail498185.htm.
[15]张洪柱.高效工业煤粉炉替代传统工业锅炉的实践与研究[D].天津:天津大学,2017.
[16] ASIF M,KIM W S.Numerical study of NOxabatement using ozone injection integrated with wet absorption[J].Ozone Science&Engineering,2014,36(5):472-484.
[17] MA Qiang,WANG Z H,LIN F W,et al.Characteristics of O3oxidation for simultaneous desulfurization and denitration with limestone-gypsum wet scrubbing:Application in a carbon black drying kiln furnace[J].Energy&Fuels,2016,30(3):2302-2308.
[18]林法伟,朱燕群,徐超群,等.臭氧多脱过程中残留臭氧的分解试验研究[J].浙江大学学报(工学版),2015,49(7):1249-1254.LIN Fawei,ZHU Yanqun,XU Chaoqun,et al. Experimental study of residual ozone decomposition in process of multi-pollutants removal by ozone[J]. Journal of Zhejiang University(Engineering Science),2015,49(7):1249-1254.
[2]中华人民共和国环境保护部.全面实施燃煤电厂超低排放和节能改造工作方案[EB/OL].[2015-12-11]. http://power. inen.com/html/power-2249399.shtml.
[3]陈玉龙,王锐.关于锅炉脱硝改造后产生堵灰及腐蚀问题探讨[J].锅炉制造,2018(6):40-41.CHEN Yulong,WANG Rui. Discussion on blockage and corrosion of boiler after denitrification[J]. Boiler Manufacturing,2018(6):40-41.
[4]宫家宏.电站煤粉炉氮氧化物控制技术[J].电力设备管理,2018(10):84-88.GONG Jiahong. Nitrogen oxide control technology for pulverized coal fired boilers in power plants[J]. Electric Power Equipment Management,2018(10):84-88.
[5]STBERG M,DAM-JOHANSEN K.Empirical modeling of the selective non-catalytic reduction of no:Comparison with large-scale experiments and detailed kinetic modeling[J].Chemical Engineering Science,1994,49(12):1897-1904.
[6]王小娥.选择性非催化还原烟气脱硝技术在CFB锅炉及煤粉炉上的应用比较[D].上海:上海交通大学,2014.
[7]姜树栋.利用臭氧及活性分子协同脱除多种污染物的实验及机理研究[D].杭州:浙江大学,2010.
[8]王智化.燃煤多种污染物一体化协同脱除机理及反应射流直接数值模拟DNS的研究[D].杭州:浙江大学,2005.
[9]张建平,万凯迪,王荣涛,等.生物质循环流化床锅炉臭氧脱硝试验研究[J].环境工程技术学报,2019,9(1):8-13.ZHANG Jianping,WAN Kaidi,WANG Rongtao,et al.Experimental study on ozone denitration of a biomass circulating fluidized bed boiler[J].Journal of Environmental Engineering Technology,2019,9(1):8-13.
[10]朱燕群,杨业,黄建鹏,等.橡胶厂60 000 m3/h炭黑干燥炉烟气臭氧脱硝试验研究[J].浙江大学学报(工学版),2016,50(10):1865-1870.ZHU Yanqun,YANG Ye,HUANG Jianpeng,et al. Removal of NOxby ozone oxidation from flue gas of 60 000 m3/h carbon black drying furnace of rubber plant[J].Journal of Zhejiang University(Engineering Science),2016,50(10):1865-1870.
[11]马强.烟气中多种污染物超低排放的活性分子氧化及一体化脱除机理研究[D].杭州:浙江大学,2016.
[12] WANG Z H,ZHOU J H,ZHU Y Q,et al.Simultaneous removal of NOx,SO2and Hg in nitrogen flow in a narrow reactor by ozone injection:Experimental results[J]. Fuel Processing Technology,2007,88(8):817-823.
[13]国家市场监督管理总局.煤炭质量分级第1部分:灰分:GB/T 15224. 1—2018[S/OL].[2018-09-01]. http://www.gb688. cn/bzgk/gb/newGbInfo? hcno=0B7290DEB716BE83A82D1B5E86DAFC13.
[14]煤炭工业协会.煤炭质量分级第2部分:硫分:GB/T 15224.2—2010[S/OL].[2010-09-26]. http://www. zbgb. org/2/StandardDetail498185.htm.
[15]张洪柱.高效工业煤粉炉替代传统工业锅炉的实践与研究[D].天津:天津大学,2017.
[16] ASIF M,KIM W S.Numerical study of NOxabatement using ozone injection integrated with wet absorption[J].Ozone Science&Engineering,2014,36(5):472-484.
[17] MA Qiang,WANG Z H,LIN F W,et al.Characteristics of O3oxidation for simultaneous desulfurization and denitration with limestone-gypsum wet scrubbing:Application in a carbon black drying kiln furnace[J].Energy&Fuels,2016,30(3):2302-2308.
[18]林法伟,朱燕群,徐超群,等.臭氧多脱过程中残留臭氧的分解试验研究[J].浙江大学学报(工学版),2015,49(7):1249-1254.LIN Fawei,ZHU Yanqun,XU Chaoqun,et al. Experimental study of residual ozone decomposition in process of multi-pollutants removal by ozone[J]. Journal of Zhejiang University(Engineering Science),2015,49(7):1249-1254.
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