混煤燃烧中的交互作用:掺烧方式和配风对着火和燃尽特性的影响
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摘要
以某台布置双一次风喷口的试验炉为研究对象,采用数值模拟方法研究了混煤掺烧方式和优化配风对着火和燃尽特性的影响,揭示了氧竞争作用对混煤燃尽抑制的机理,并给出了优化调控方法。结果表明:掺烧方式是影响混煤燃烧着火特性的重要因素;在炉外掺混方式下,掺入高挥发分煤能够改善低挥发分煤的着火特性;掺烧方式对低挥发分煤燃尽特性的影响更显著;炉内掺烧方式可抑制混煤燃烧过程中的氧竞争作用,提高低挥发分煤的燃尽率;合理调整二次风配风量可进一步提高低挥发分煤的燃尽率和混煤的总燃尽率。
Taking the test furnace with double primary air nozzles as an object of study, numerical simulations were conducted to study the effects of coal blend way and air distribution mode on the ignition and burnout characteristics of the blended coal, and to reveal the inhibition mechanism of oxygen competition on the burnout rate, following which, optimal regulation methods were proposed. Results show that the coal blend way is an important factor that affects the ignition characteristics of the blended coal. In the out-furnace blend way, the ignition characteristics of low-volatile coal could be improved by blending in high-volatile coal, indicating that the coal blend way has significant influence on the burnout characteristics of low-volatile coal; whereas, in the in-furnace blend way, the oxygen competition could be inhibited between the low-and the high-volatile coal, while the burnout rate of low-volatile coal could be improved. Reasonable adjustment of secondary air distribution could further improve the burnout rate of both the low-volatile coal and the coal mixture.
Taking the test furnace with double primary air nozzles as an object of study, numerical simulations were conducted to study the effects of coal blend way and air distribution mode on the ignition and burnout characteristics of the blended coal, and to reveal the inhibition mechanism of oxygen competition on the burnout rate, following which, optimal regulation methods were proposed. Results show that the coal blend way is an important factor that affects the ignition characteristics of the blended coal. In the out-furnace blend way, the ignition characteristics of low-volatile coal could be improved by blending in high-volatile coal, indicating that the coal blend way has significant influence on the burnout characteristics of low-volatile coal; whereas, in the in-furnace blend way, the oxygen competition could be inhibited between the low-and the high-volatile coal, while the burnout rate of low-volatile coal could be improved. Reasonable adjustment of secondary air distribution could further improve the burnout rate of both the low-volatile coal and the coal mixture.
引文
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[14] SMOOT L D,SMITH P J.Coal combustion and gasification[M].New York,USA:Plenum Press,1985.
[2] IKEDA M.Development of technology for reducing NOx emission and unburned carbon concentration in fly ash using in-furnace blending method[R].Japan:CRIEPI,2008.
[3] 段学农,朱光明,焦庆丰,等.电厂锅炉混煤掺烧技术研究与实践[J].中国电力,2008,41(6):51-54.DUAN Xuenong,ZHU Guangming,JIAO Qingfeng,et al.Research and practice of blended coal combustion technology in power plant boiler[J].Electric Power,2008,41(6):51-54.
[4] 高正阳,方立军,叶学民,等.无烟煤与烟煤混煤燃烧性能的热重实验研究[J].华北电力大学学报,2001,28(1):39-42.GAO Zhengyang,FANG Lijun,YE Xuemin,et al.Thermal gravity investigation on combustion performance of blended coal from anthracite and bituminous[J].Journal of North China Electric University,2001,28(1):39-42.
[5] RUBIERA F,ARENILLAS A,ARIAS B,et al.Modification of combustion behaviour and NO emissions by coal blending[J].Fuel Processing Technology,2002,77-78:111-117.
[6] BISWAS S,CHOUDHURY N,SARKAR P,et al.Studies on the combustion behaviour of blends of Indian coals by TGA and drop tube furnace[J].Fuel Processing Technology,2006,87(3):191-199.
[7] MILENKOVA K S,BORREGO A G,ALVAREZ D,et al.Tracing the origin of unburned carbon in fly ashes from coal blends[J].Energy & Fuels,2003,17(5):1222-1232.
[8] 翁安心,周昊,张力,等.不同煤种混煤燃烧时NOx生成和燃尽特性的试验[J].热能动力工程,2004,19(3):242-245.WENG Anxin,ZHOU Hao,ZHANG Li,et al.Experimental research of the NOx generation and burnout characteristics during the combustion of blended coals[J].Journal of Engineering for Thermal Energy and Power,2004,19(3):242-245.
[9] LEE B H,KIM S,SONG J,et al.Influence of coal blending methods on unburned carbon and NO emissions in a drop-tube furnace[J].Energy & Fuels,2011,25(11):5055-5062.
[10] LEE B H,EDDINGS E G,JEON C H.Effect of coal blending methods with different excess oxygen on unburned carbon and NOx emissions in an entrained flow reactor[J].Energy & Fuels,2012,26(11):6803-6814.
[11] 杨建国,叶凌云,赵敏,等.基于煤种掺烧模式的锅炉燃烧NOx预测模型[J].动力工程学报,2017,37(11):870-875.YANG Jianguo,YE Lingyun,ZHAO Min,et al.NOx prediction model for multi-coal admixing combustion in boiler[J].Journal of Chinese Society of Power Engineering,2017,37(11):870-875.
[12] 马仑,汪涂维,方庆艳,等.混煤燃烧过程中的交互作用:机理实验研究与数值模拟[J].煤炭学报,2015,40(11):2647-2653.MA Lun,WANG Tuwei,FANG Qingyan,et al.Interaction of blended-coal combustion process:experimental study and numerical simulation of mechanism[J].Journal of China Coal Society,2015,40(11):2647-2653.
[13] 马仑,汪涂维,方庆艳,等.混煤燃烧过程中的交互作用:掺混方式对混煤燃烧特性的影响[J].煤炭学报,2016,41(9):2340-2346.MA Lun,WANG Tuwei,FANG Qingyan,et al.Interaction of blended-coal combustion process:influence of coal blending methods on combustion characteristics[J].Journal of China Coal Society,2016,41(9):2340-2346.
[14] SMOOT L D,SMITH P J.Coal combustion and gasification[M].New York,USA:Plenum Press,1985.