除焦剂对燃用准东煤350MW煤粉炉结渣及沾污的影响
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摘要
新疆准东煤中碱及碱土金属元素含量高是造成燃用准东煤锅炉结渣、沾污问题的根本原因,硫酸盐与飞灰中的Fe_2O_3、Al_2O_3及烟气中的SO_3反应,形成复合硫酸盐,这些产物在500℃～800℃范围内呈熔融粘性物质性,以这层为黏结剂继续捕集飞灰粒子,继续形成黏结物,加剧了灰颗粒之间的粘连、团聚、凝并进而导致其具有极强的沾污和结渣特性。通过对其机理的分析,认为对灰的成分特性改变,改善煤灰硅铝比失调,调节煤灰的碱酸比能够提高灰熔点温度,缓减结渣及沾污程度。为此,选用某铝基固态粉末除焦剂,在某燃用准东煤350MW煤粉炉进行评价,在使用除焦剂前后分别对各典型温度区间受热面的结渣/沾污样品进行取样,并进行组分分析及元素分析。结果表明,使用除焦剂后可降低屏过区域的渣块硬度,其主要原因在于除焦剂添加后显著提高了Al和Si的含量,但受到除焦剂喷入量级喷入位置的影响,对其他受热面的预防沾污及结渣的效果并不显著,沾污样品成分改变不显著,表明除焦剂的改善范围主要集中在从喷入除焦剂至末级再热器前端的区域,因而对准东煤锅炉的结渣及沾污改善作用比较有限。
The main cause of slagging and contamination of Zhundong Coal Boiler is forming of compound sulfate sodium sulfate which reaction of sulfate with Fe_2O_3, Al_2O_3 in fly ash and SO_3 in flue gas.This compound sulfate sodium sulfate fuse viscous substance in the range of 500℃～800℃,continuous capture of fly ash particles using this layer as binder,continue to form bonds. Ultimately, the adhesion, agglomeration and coagulation of ash particles are aggravated, which leads to their strong fouling and slagging characteristics.Through the analysis of its mechanism, it is considered that the change of ash composition characteristics, the improvement of silica-aluminium ratio of coal ash and the adjustment of alkali-acid ratio of coal ash can increase ash melting point temperature and slow down slagging and contamination.Therefore, an aluminium-based solid powder coke remover is selected,evaluation of a 350MW Pulverized Coal Furnace Fueled with Jundong Coal. Sampling of slagging/contamination samples on heating surfaces of typical temperature ranges before and after coke removal agent,component analysis and elemental analysis were carried out.The results show that the hardness of slag blocks in the screen area can be reduced by using the coke remover. The main reason is that the content of Al and Si is significantly increased after adding the coke remover. However, the effect of the injection position of the coke remover on the prevention of fouling and slagging of other heating surfaces is not significant. The change of the composition of the contaminated samples is not significant, indicating that the improvement of the coke remover is mainly concentrated in the following areas. Since the coke remover is injected into the front end of the last stage reheater, the slagging and contamination improvement of the Zhuandong Coal Boiler is limited.
The main cause of slagging and contamination of Zhundong Coal Boiler is forming of compound sulfate sodium sulfate which reaction of sulfate with Fe_2O_3, Al_2O_3 in fly ash and SO_3 in flue gas.This compound sulfate sodium sulfate fuse viscous substance in the range of 500℃～800℃,continuous capture of fly ash particles using this layer as binder,continue to form bonds. Ultimately, the adhesion, agglomeration and coagulation of ash particles are aggravated, which leads to their strong fouling and slagging characteristics.Through the analysis of its mechanism, it is considered that the change of ash composition characteristics, the improvement of silica-aluminium ratio of coal ash and the adjustment of alkali-acid ratio of coal ash can increase ash melting point temperature and slow down slagging and contamination.Therefore, an aluminium-based solid powder coke remover is selected,evaluation of a 350MW Pulverized Coal Furnace Fueled with Jundong Coal. Sampling of slagging/contamination samples on heating surfaces of typical temperature ranges before and after coke removal agent,component analysis and elemental analysis were carried out.The results show that the hardness of slag blocks in the screen area can be reduced by using the coke remover. The main reason is that the content of Al and Si is significantly increased after adding the coke remover. However, the effect of the injection position of the coke remover on the prevention of fouling and slagging of other heating surfaces is not significant. The change of the composition of the contaminated samples is not significant, indicating that the improvement of the coke remover is mainly concentrated in the following areas. Since the coke remover is injected into the front end of the last stage reheater, the slagging and contamination improvement of the Zhuandong Coal Boiler is limited.
引文
[1]张守玉,陈川,施大钟,等. 高钠煤燃烧利用现状[J]. 中国电机工程学报,2013(5):1-12.
[2]陈衡, 王云刚,马海东,等. 循环流化床锅炉燃用准东煤结渣、沾污分析[J]. 热能动力工程,2015,30(3):431-435.
[3]郝丽芬,李东雄,靳智平. 灰成分与灰熔融性关系的研究[J]. 电力学报,2006(3):294-296+300.
[4]贾明生,张乾熙. 影响煤灰熔融性温度的控制因素[J]. 煤化工,2007(3):1-5.
[5]Vorres. Melting behavior of coal ash materials from coal ash composition[J]. Quaternary International,1977,371(2):197-208.
[6]Zhu Chuan, Qu Sijian, Zhang Jing, et al. Distribution, occurrence and leaching dynamic behavior of sodium in Zhundong coal[J]. Fuel,2017(190):189-197.
[7]董明钢. 高钠煤对锅炉受热面结渣、沾污和腐蚀的影响及预防措施[J]. 热力发电,2008,37(9):35-39.
[8]王彦林,郭前鑫,翟文东. 燃用哈密高钠高氯煤的超临界锅炉设计和运行[J]. 中国电力,2014,47(4):60-64.
[9]Du Yongbo, Wang Changan, Lv Qiang, et al. Influence of sodium on deactivation and regeneration of SCR catalyst during utilization of Zhundong coals[J]. Asia-Pacific Journal of Chemical Engineering, 2016,11(6):973-980.
[10]Li Mingqiang,Zhang Zhongxiao,Wu Xiaojiang,et al. Experiment and mechanism study on the effect of kaolin on melting characteristics of Zhundong coal ash[J]. Energy and Fuels,2016,30(9):7763-7769.
[11]张磊.除焦剂在大型火电机组锅炉的应用与研究[J]. 华电技术,2016,38(4):18-21,78.
[12]刘成武. 液态除焦剂在燃煤电厂锅炉上的应用[A]. 全国火电200MW级机组协作会.全国火电200MW级机组技术协作会第二十三届年会论文集[C].2005.
[13]黄祖文. SG-420/140-M417锅炉结焦分析和预防措施[J]. 华东电力,1994(5):38-39.
[14]杨忠灿,刘家利,何红光. 新疆准东煤特性研究及其锅炉选型[J]. 热力发电,2010,39(8):38-40,44.
[15]Li Guangyu, Wang ChangAn, Yan Yu, et al. Release and transformation of sodium during combustion of Zhundong coals[J]. Journal of the Energy Institute,2016,89(1):48-56.
[16]魏博,王学斌,张利孟,等. 掺烧废弃硅粉对准东煤钠迁徙及灰熔融影响的实验研究[J]. 中国电力,2014,47(10):98-102,116.
[17]沈铭科,邱坤赞,黄镇宇,等. 准东煤掺烧高岭土对固钠率及灰熔融特性影响研究[J]. 燃料化学学报,2015,43(09):1044-1051.
[18]张利孟,董信光,刘科,等. 高岭土对准东煤结渣特性及矿物质演变的影响[J]. 燃料化学学报,2015,43(10):1176-1181.
[19]李江浩.电站锅炉高比例掺烧准东煤的运行与调整[J]. 锅炉技术,2016(2):1-3.
[20]徐生荣. 锅炉除焦剂使用效果分析[J]. 南京师范大学学报(工程技术版),2007(3):44-47.
[21]池作和,周昊,蒋啸,等. 锅炉结渣机理及防结渣技术措施研究[J]. 热力发电,1999(4):26-30,63.
[22]楼亿红. 动力用煤结渣倾向的判断[J]. 热力发电,2004(5):68-70,83.
[23]GB/T 219-2008, 煤灰熔融性的测定方法[S].
[2]陈衡, 王云刚,马海东,等. 循环流化床锅炉燃用准东煤结渣、沾污分析[J]. 热能动力工程,2015,30(3):431-435.
[3]郝丽芬,李东雄,靳智平. 灰成分与灰熔融性关系的研究[J]. 电力学报,2006(3):294-296+300.
[4]贾明生,张乾熙. 影响煤灰熔融性温度的控制因素[J]. 煤化工,2007(3):1-5.
[5]Vorres. Melting behavior of coal ash materials from coal ash composition[J]. Quaternary International,1977,371(2):197-208.
[6]Zhu Chuan, Qu Sijian, Zhang Jing, et al. Distribution, occurrence and leaching dynamic behavior of sodium in Zhundong coal[J]. Fuel,2017(190):189-197.
[7]董明钢. 高钠煤对锅炉受热面结渣、沾污和腐蚀的影响及预防措施[J]. 热力发电,2008,37(9):35-39.
[8]王彦林,郭前鑫,翟文东. 燃用哈密高钠高氯煤的超临界锅炉设计和运行[J]. 中国电力,2014,47(4):60-64.
[9]Du Yongbo, Wang Changan, Lv Qiang, et al. Influence of sodium on deactivation and regeneration of SCR catalyst during utilization of Zhundong coals[J]. Asia-Pacific Journal of Chemical Engineering, 2016,11(6):973-980.
[10]Li Mingqiang,Zhang Zhongxiao,Wu Xiaojiang,et al. Experiment and mechanism study on the effect of kaolin on melting characteristics of Zhundong coal ash[J]. Energy and Fuels,2016,30(9):7763-7769.
[11]张磊.除焦剂在大型火电机组锅炉的应用与研究[J]. 华电技术,2016,38(4):18-21,78.
[12]刘成武. 液态除焦剂在燃煤电厂锅炉上的应用[A]. 全国火电200MW级机组协作会.全国火电200MW级机组技术协作会第二十三届年会论文集[C].2005.
[13]黄祖文. SG-420/140-M417锅炉结焦分析和预防措施[J]. 华东电力,1994(5):38-39.
[14]杨忠灿,刘家利,何红光. 新疆准东煤特性研究及其锅炉选型[J]. 热力发电,2010,39(8):38-40,44.
[15]Li Guangyu, Wang ChangAn, Yan Yu, et al. Release and transformation of sodium during combustion of Zhundong coals[J]. Journal of the Energy Institute,2016,89(1):48-56.
[16]魏博,王学斌,张利孟,等. 掺烧废弃硅粉对准东煤钠迁徙及灰熔融影响的实验研究[J]. 中国电力,2014,47(10):98-102,116.
[17]沈铭科,邱坤赞,黄镇宇,等. 准东煤掺烧高岭土对固钠率及灰熔融特性影响研究[J]. 燃料化学学报,2015,43(09):1044-1051.
[18]张利孟,董信光,刘科,等. 高岭土对准东煤结渣特性及矿物质演变的影响[J]. 燃料化学学报,2015,43(10):1176-1181.
[19]李江浩.电站锅炉高比例掺烧准东煤的运行与调整[J]. 锅炉技术,2016(2):1-3.
[20]徐生荣. 锅炉除焦剂使用效果分析[J]. 南京师范大学学报(工程技术版),2007(3):44-47.
[21]池作和,周昊,蒋啸,等. 锅炉结渣机理及防结渣技术措施研究[J]. 热力发电,1999(4):26-30,63.
[22]楼亿红. 动力用煤结渣倾向的判断[J]. 热力发电,2004(5):68-70,83.
[23]GB/T 219-2008, 煤灰熔融性的测定方法[S].