多反应控制段携带流反应器试验系统设计及优化研究
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摘要
煤粉燃烧的过程中会产生大量烟尘、SO_2、NOx和CO_2等大气污染物,同时还会释放出有害有毒的微量金属元素,如:Hg、Pb、As、Se等,对环境及人体健康危害很大。因此,解决燃煤污染问题已经迫在眉睫。通过燃烧法控制反应条件以及投入添加剂脱除大部分的NOx,并在一定程度上脱除SOx和汞,再进一步配合其他中、低温燃烧污染物控制技术,可以大大降低锅炉进行污染物脱除和控制的成本,获得良好的经济效益。
本文首先介绍了国内外燃烧法控制污染物减排的研究现状,阐述了炉内联合脱除NOx、SO_2和汞的意义;借鉴德国斯图加特大学携带流燃烧反应器参数,设计搭建了多反应控制段携带流反应器多功能试验系统。它主要包括反应器炉体、给粉系统、温度控制系统、气体供给系统、取样分析系统、冷却系统和排烟系统。
为了了解试验台整体性能,对实验系统进行了调试试验,包括:系统气密性、油冷却系统、给料系统等调试试验,并进行了炉内温度场标定试验、结渣试验以及煤粉燃烧特性试验。针对炉内大给粉量燃烧不稳定引起的爆燃、炉内风粉混合不均匀、煤粉燃尽效果较差等问题,提出了在炉内加入侧二次风的改进措施。利用FLUENT数值模拟软件,对改进后的结构进行了数值模拟,通过对炉内流场速度分布、颗粒轨迹、颗粒浓度,以及炉内各水平截面及中心截面O_2、CO、CO_2摩尔浓度的分析,优化了相关参数,得出侧二次风位置h=37mm,风量配比:Q1=30%、Qh=20%、Qc=50%是本次试验的优化方案中的最好的改造方案。改进后的调试试验结果表明,加入侧二次风措施可有效改善炉内风粉混合问题,优化炉内燃烧。
During the process of coal combustion, large amount of pollutant is produced, such as SO_2、NOx、CO_2 etc, and harmful toxic trace metal elements are released, such as Hg、Pb、As、Se etc,which do great harm to the eco-enviroment and human health. Consequently, the coal-fired pollution problems become more and more urgent. At present,most NOx can be removed from flue gas by controlling the combustion reaction conditions and putting additives into the furnace while some SOx and mercury also can be removed at the same time. Furtherly,It is more significant that this technology is used with other moderate and low-temperature combustion pollution control technologies, so this can greatly reduce the costs of removal of pollutants in the boiler and get good economic benefits.Controlled by combustion reaction conditions and additives put into removal of most of the NOx, and to some extent on the removal of SO_2 and mercury. Further with the other the moderate and low-temperature combustion pollution control technologies, we can greatly reduce the costs of removal of pollutants in the boiler and get good economic benefits.
First of all, in this paper the background and present state of subject research about combustion tenologies of control pollutants in domestic. home and abroad are discussed, introducing the significance of combuined removal the NOx、SO_2、Hg at high temperature in the boiler. Refering to the Entrained Flow Reactor in University of Stuttgart, the Entrained Flow Combuster with Multiple Reaction Segment versatile experiment system was designed and built. The experiment system could do research on combined removal of NOx、SO_2、Hg in furnace simulataneously, including reactor furnace, the feeding system, temperature control system, gas supply system, the sample analysis system, cooling system and exhaust emission system etc.
In order to get the total functions of the experiment system, much experiment of debug system was done, including the tests of air-tightness、oil cooling system and feeding system, what’s more, calibration experiment of the furnace temperature、slagging experiment and combustion characteristics of coal. During the experiment, some problems such as deflagration when feeding large amount of coal、heterogeneous mixtures of the furnace wind were discovered. In order to optimize the system, adding the two sides secondary air measure in the furnace and doing numerical simulation of the reformed structure. By analyzing the results of cold numerical simulation results and the horizontal sections and the center sections mole fraction of O_2, CO, CO_2, we got the most optimal program.
The result of doing experiment at the reformed structure prove the optional method can effectively improve the heterogeneous mixtures of the furnace wind problem and combustion conditions.
本文首先介绍了国内外燃烧法控制污染物减排的研究现状,阐述了炉内联合脱除NOx、SO_2和汞的意义;借鉴德国斯图加特大学携带流燃烧反应器参数,设计搭建了多反应控制段携带流反应器多功能试验系统。它主要包括反应器炉体、给粉系统、温度控制系统、气体供给系统、取样分析系统、冷却系统和排烟系统。
为了了解试验台整体性能,对实验系统进行了调试试验,包括:系统气密性、油冷却系统、给料系统等调试试验,并进行了炉内温度场标定试验、结渣试验以及煤粉燃烧特性试验。针对炉内大给粉量燃烧不稳定引起的爆燃、炉内风粉混合不均匀、煤粉燃尽效果较差等问题,提出了在炉内加入侧二次风的改进措施。利用FLUENT数值模拟软件,对改进后的结构进行了数值模拟,通过对炉内流场速度分布、颗粒轨迹、颗粒浓度,以及炉内各水平截面及中心截面O_2、CO、CO_2摩尔浓度的分析,优化了相关参数,得出侧二次风位置h=37mm,风量配比:Q1=30%、Qh=20%、Qc=50%是本次试验的优化方案中的最好的改造方案。改进后的调试试验结果表明,加入侧二次风措施可有效改善炉内风粉混合问题,优化炉内燃烧。
During the process of coal combustion, large amount of pollutant is produced, such as SO_2、NOx、CO_2 etc, and harmful toxic trace metal elements are released, such as Hg、Pb、As、Se etc,which do great harm to the eco-enviroment and human health. Consequently, the coal-fired pollution problems become more and more urgent. At present,most NOx can be removed from flue gas by controlling the combustion reaction conditions and putting additives into the furnace while some SOx and mercury also can be removed at the same time. Furtherly,It is more significant that this technology is used with other moderate and low-temperature combustion pollution control technologies, so this can greatly reduce the costs of removal of pollutants in the boiler and get good economic benefits.Controlled by combustion reaction conditions and additives put into removal of most of the NOx, and to some extent on the removal of SO_2 and mercury. Further with the other the moderate and low-temperature combustion pollution control technologies, we can greatly reduce the costs of removal of pollutants in the boiler and get good economic benefits.
First of all, in this paper the background and present state of subject research about combustion tenologies of control pollutants in domestic. home and abroad are discussed, introducing the significance of combuined removal the NOx、SO_2、Hg at high temperature in the boiler. Refering to the Entrained Flow Reactor in University of Stuttgart, the Entrained Flow Combuster with Multiple Reaction Segment versatile experiment system was designed and built. The experiment system could do research on combined removal of NOx、SO_2、Hg in furnace simulataneously, including reactor furnace, the feeding system, temperature control system, gas supply system, the sample analysis system, cooling system and exhaust emission system etc.
In order to get the total functions of the experiment system, much experiment of debug system was done, including the tests of air-tightness、oil cooling system and feeding system, what’s more, calibration experiment of the furnace temperature、slagging experiment and combustion characteristics of coal. During the experiment, some problems such as deflagration when feeding large amount of coal、heterogeneous mixtures of the furnace wind were discovered. In order to optimize the system, adding the two sides secondary air measure in the furnace and doing numerical simulation of the reformed structure. By analyzing the results of cold numerical simulation results and the horizontal sections and the center sections mole fraction of O_2, CO, CO_2, we got the most optimal program.
The result of doing experiment at the reformed structure prove the optional method can effectively improve the heterogeneous mixtures of the furnace wind problem and combustion conditions.
引文
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38. L T Aunela, et al. Trace metal emissions from the Estonian oil shale fired power plant. Fuel Processing Technology, 1998. 55: 13
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2.崔民选. 2006中国能源发展报告[M].北京:社会科学文献出版社, 2006: 1~2
3.杜雅琴,李新国等.煤炭开发与使用中的环境问题[J].矿业安全与环保, 2005,32(6): 63~65
4.罗文泉.简谈燃煤对大气的污染及其控制[J].节能技术, 2008: 1~4
5.朱法华,王胜,郑有飞.火电NOx排放现状与预测及控制对策.能源环境保护. 2005, 18(1): 21~23
6.国家统计局,环境保护部. 2004—2008中国环境统计年鉴[M].北京:中国统计出版社, 2008: 2~6
7.胡予红.煤炭对环境的影响研究[J].中国能源, 2004: 1~2
8. Wang Qichao, Shen wenguo, Ma Zhuangwei, Estimation of mercury from coal combustion in China [J]. Environ Sci Technol, 2000, 34 (13): 2711~2713
9. Schroeder W H, Munthe J, Lindqvist O. Cycling of mercury between water, air and soil compartments of the environment [J]. Water Air Soil Pollut, 1989,48(3/4) :337~347
10.王圣,朱法华.我国燃煤电厂氮氧化物控制技术与对策.王国清.中国环境科学学会.中国环境保护优秀论文精选, 2006: 5~10
11.苏亚欣,毛玉如,徐璋.燃煤氮氧化物排放控制技术.化学工业出版社, 2005: 10~13
12. Wendt, J O L, C V Sternling, M A Matovich. Reduction of sulfur trioxide and nitrogen oxides by secondary fuel injiection. Fourteenth Symposium(International) on Combustion, Pittsburgh, PA: The combustion Institute, 1973: 897
13. Y Zhao, M A Serio, R Bassilakis, P R Solomon. A Method of Predicting Coal Devolatilization Behavior Based on the Elemental Composition. 25th symposium (international) on combustion, Pittsburgh, PA: The combustion Institute, 1994: 553
14. A Williams, R Backreedy, R Habib, J M Jones, M Pourkashanian. Modelling coal combustion: the current position. Fuel, 2002. 81: 605
15. Thorne, et al. The structure of hydrogen cyanide-nitrogen dioxide premixed flames. Twenty-First Symposium (International) on Combustion, Pittsburgh, PA: The combustion Institute, 1986: 965.
16. S Chaiklangmuang, J M Jones, M Pourkashanian, A Williams. Conversion of volatile-nitrogen and char-nitrogen to NO during combustion. Fuel, 2002. 81: 2363
17. Y H Song, J H Pohl, J M Beer, A F Sarofim. Nitric oxide formation during pulverizedcoal combustion. Combust Sci Technol, 1982. 28: 31
18. C J Tullin, A F Sarofim, J M Beer. Nitric oxide reduction in the freeboard of a fluidized bed coal combustion. J Inst Energy, 1993. 66: 207
19. De Soete G G.. Heterogeneous NO and N2O formation from Bound Nitrogen during Char Combustion. 23rd symposium (international) on combustion, Pittsburgh, PA: The combustion Institute, 1990: 1257
20. A W Harding, S D Brown, K M Thomas. Release of NO from the combustion of coal chars. Combust Flame, 1996. 107: 336
21. H Teng, E Suuberg, J M Calo. Studies on the reduction of nitric oxide by carbom: The NO-carbon gasfication reacion. Energy and Fuels, 1992. 6: 398
22. A Arenillasa, et al. Char acterisation of model compounds and a synthetic coal by. TG/MS/FTIR to represent the pyrolysis behaviour. Environ Sci Technol, 2002. 36: 5498
23. A Arenillasa, et al. Modelling of NO formation in the combustion of coal blends. Fuel, 1999. 78: 1779
24. Y H Song, J M Beer, A F Sarofim. Oxidation and devolatilization of nitrogen in coal char. Combust Sci Technol, 1981. 25: 237
25. J M Levy, L K Chan, A F Sarofim, J M Beer. NO/char reactions at pulverized coal flame condition. Eighteenth symposium (international) on combustion, Pittsburgh, PA: The Combustion Institute, 1981: 111
26. C Sch?nenbeck, R Gadiou, D Schwartz. A kinetic study of the high temperature NO-char reaction. Fuel, 2004. 83: 443
27.钟北京,姚海军,何裕昆等.超细CaO粉炉内喷射脱硫的实验研究.工程热物理学报, 2002. 23 (1): 127
28. L Yan, Boon Chye Loh, et al. Chain reaction mechanism by NOx in SO2 removal process. Energy and Fuels, 2002. 16: 155
29. L Yan, Masateru Nishioka, et al. High calcium utilization and gypsum formation for dry desulfurization process. Energy and Fuels, 1999. 13: 1015
30. E Kakaras, D Giannakopoulos. Modeling of flue gas desulfurization using dry additives. Chemical Engineering and Processing, 1995. 34: 421
31.张忠孝.低成本炉内喷钙脱硫技术研究.能源研究与信息, 1999. 15 (2): 25
32.王泉海,邱建荣,吴昊.煤燃烧过程中汞释放的研究现状.热能动力工程, 2002. 17(11): 547
33.刘晶,刘迎晖,郑楚光.燃煤烟气中汞形态分析的实验研究.环境化学, 2003.22(2): 172
34.刘晶,王满辉,郑楚光.煤燃烧过程中汞与含氯气体的反应机理的研究.工程热物理学报, 2003. 24(1): 161
35.韩军,徐明厚.燃煤痕量元素排放的控制研究.动力工程, 2003. 23(6): 2744
36. J H Pavlish, et al. SCR catalyst performance in flue gases derived from subbituminous and lignite coals. Fuel Processing Technology, 2005. 85: 563
37. Benson, A Steven. Mercury control testing in a pulverized lignite-fired system. Fuel Processing Technology, 2003. 82: 89
38. L T Aunela, et al. Trace metal emissions from the Estonian oil shale fired power plant. Fuel Processing Technology, 1998. 55: 13
39. C Senior, C J Bustard. Characterization of fly ash from full-scale demonstration of sorbent. Fuel Processing Technology, 2004. 85: 601
40.金峰,曾汉才,钟毅,张鹏宇,许绿丝.颗粒活性炭对汞的吸附实验研究.电力科学与工程, 2003. 1(1): 1
41. K C Galbreath, C J Zygarlicke. Mercury transformations in coal combustion flue gas Fuel Processing Technology, 2000. 65: 289
42.施正伦,骆仲泱,岑可法.石煤流化床燃烧重金属排放特性试验研究.煤炭学报, 2001. 26(2): 209
43. A C Wiley. Final Technical Report on Department of Energy Grant DE-FC26-
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