ZHENG Guibo;WU Jianqun;WU Hao;XUE Ningtao;LIU Fangqi;XU Guorong;YU Dunxi;

• 1:Guangdong Yuedian Jinghai Power Generation Co.
• 2:Ltd.
• 3:State Key Laboratory of Coal Combustion
• 4:Huazhong University of Science & Technology

Abstract：

The peak load regulation operation of coal-fired units is an important measure to improve the consumption capacity of renewable energy, but it will have an evident impact on fuel combustion process and system. Fly ash properties are closely related to ash slagging behavior, dust removal equipment performance and particulate matter emission. However, little research has been done in the past. The influence of load change of coal-fired boiler on fly ash characteristics was studied to guide the prevention and control of ash related problems such as furnace fouling and slagging and particulate matter emission. In this work, fly ashes were sampled before ESP in a 1 000 MW coal-fired boiler under 60% and 90% operating load. Chemical composition, mineral species, particle size distributions and shape characteristics of fly ash were analyzed by advanced computer automatically controlled scanning electron microscope(CCSEM). The fly ash fusibility was analyzed by a digital imaging coal ash fusibility system. The effects of boiler operating load changing on ash properties and ash melting behaviors were investigated. The results show that changing of operation load has insignificant effect on fly ash chemical composition. Degree of mineral interaction is the key factor affecting the particle size distribution of fly ash. Low operation load of boiler suppresses the migration of Ca and Fe bearing minerals in coal to aluminosilicates, which results in finer fly ash particle size distribution. The D_(50) of fly ash decreases from about 40 μm to 30 μm. Compared withfly ash in low load operation condition, the melting of fly ash in the furnace under the low load operation condition is restrained. The proportion of molten fly ash from low load operation condition is about 10% lower than that from the high load operation condition, which is mainly attributed to the lower combustion temperature under low load operation condition.

Key Words： coal combustion;fly ash;load change;CCSEM;ash melting

Abstract:

Keywords:

Foundation: 国家重点研发计划资助项目(2016YFB0600600);; 中国博士后科学基金资助项目(2020M672351);; 国家自然科学基金资助项目(52006080)

Authors: ZHENG Guibo;WU Jianqun;WU Hao;XUE Ningtao;LIU Fangqi;XU Guorong;YU Dunxi;

DOI: 10.13226/j.issn.1006-6772.21101202

References：

• [1] 中电联电力统计与数据中心.2020-2021年度全国电力供需形势分析预测报告[EB/OL].(2021-02-06)[2021-10-10].https://cec.org.cn/detail/ index.htm / 3- 293398.
• [2] 马达夫，张守玉，何翔，等.煤粉锅炉超低负荷运行的技术问题和应对措施[J].动力工程学报，2019,39(10):784-791,803.MA Dafu,ZHANG Shouyu,HE Xiang,et al.Technical problems occurring in ultra-low load operation of pulverized coal-fired boilers and the solutions[J].Journal of Chinese Society of Power Engineering,2019,39(10):784-791,803.
• [3] 景雪晖，唐权利，朱建平，等.低负荷一次风掺烟量对Π型切圆锅炉NOx生成特性影响[J].热力发电，2020,49(12):84-88.JING Xuehui,TANG Quanli,ZHU Jianping,et al.Effect of mixing ratio of flue gas in primary air on NOx generation characteristics in π-type tangen[J].Thermal Power Generation,2020,49(12):84-88.
• [4] 罗自学，刘成永，陶茂钢，等.直流锅炉风/煤比燃烧优化控制的研究[J].动力工程，2008,28(5):731-734.LUO Zixue,LIU Chengyong,TAO Maogang,et al.Combustion control of optimized wind-coal ratio in once-through boiler[J].Journal of Power Engineering,2008,28(5):731-734.
• [5] 周俊波，刘茜，张华，等.典型燃煤锅炉低负荷及变负荷运行控制特性分析[J].热力发电，2018,47 (9):38-44.ZHOU Junbo,LIU Xi,ZHANG Hua,et al.Control characteristic analysis of typical coal-fired boilers during low load or variable load running[J].Thermal Power Generation,2018,47 (9):38-44.
• [6] 王树民.燃煤电厂近零排放综合控制技术及工程应用研究[D].北京：华北电力大学，2017:77-109.
• [7] 李洋，罗林，吴建群，等.1 000 MW燃煤机组负荷变化对颗粒物排放的影响规律[J].洁净煤技术，2021,27(6):115-120.LI Yang,LUO Lin,WU Jianqun,et al.Impact of load change on PM emission from an 1 000 MW coal-fired unit[J].Clean Coal Technology,2021,27(6):115-120.
• [8] 朱志飞，王礼鹏，祁慧，等.660 MW燃煤机组锅炉飞灰颗粒物排放特征研究[J].燃料化学学报，2014,42(3):323-328.ZHU Zhifei,WANG Lipeng,QI Hui,et al.Emission characteristics of fine particulate matters from a 660 MW coal-fired boiler[J].Journal of Fuel Chemistry and Technology,2014,42(3):323-328.
• [9] 吴乐，吴建群，罗嘉，等.煤样不同密度组分中致渣矿物特性的CCSEM研究[J].化工学报，2014,65 (8):3221-3227.WU Le,WU Jianqun,LUO Jia,et al.CCSEM investigation on slagging minerals in different density ingredients of bituminous coal samples[J].CIESC Journal,2014,65 (8):3221-3227.
• [10] 刘芳琪，于敦喜，吴建群，等.燃煤锅炉SCR对颗粒物排放特性影响[J].化工学报，2018,69 (9):4051-4057.LIU Fangqi,YU Dunxi,WU Jianqun,et al.Effect of SCR on particulate matter emissions from a coal-fired boiler[J].CIESC Journal,2018,69 (9):4051-4057.
• [11] 于敦喜.燃煤细微颗粒物的模态识别及其形成机理[D].武汉：华中科技大学，2007:31-33.
• [12] WU J,YU D,ZENG X,et al.Impacts of CO2 on the pyrite-kaolinite interaction and the product sintering strength[J].Proceedings of the Combustion Institute,2019,37 (4):4479-4486.
• [13] 陈胜，于敦喜，吴建群，等.新疆高钙煤混烧对灰中含钙矿物熔融特性影响[J].化工学报，2020,71(9):4260-4269.CHEN Sheng,YU Dunxi,WU Jianqun,et al.Effects of Xinjiang high calcium coal co-firing on melting characteristics of Ca-bearing minerals in ash[J].CIESC Journal,2020,71(9):4260-4269.
• [14] RAASK E,Mineral impurities in coal combustion,behavior,pro-blems,and remedial measures[M].Washington:Hemisphere Publishing Corporation,1985:239-259.
• [15] 隋子峰.燃煤电厂亚微米颗粒物形成机理及释放规律研究[D].北京：华北电力大学，2018:48-60.
• [16] 刘建忠，范海燕，周俊虎，等.煤粉炉PM10/PM2.5排放规律的试验研究[J].中国电机工程学报，2003(1):146-150.LIU Jianzhong,FAN Haiyan,ZHOU Junhu,et al.Experimental studies on the emission of PM10 and PM2.5 from coal-fired boiler[J].Proceedings of the Chinese Society for Electrical Engineering,2003(1):146-150.
• [17] HUFFMAN G,SHAH N,CPREK N,et al.CCSEM investigation of respirable quartz in air samples collected during power plant maintenance activities[J].Fuel,2012,95:365-370.
• [18] WEN C,XU M,ZHOU K,et al.The melting potential of various ash components generated from coal combustion:Indicated by the circularity of individual particles using CCSEM technology[J].Fuel Processing Technology,2015,133:128-136.
• [19] 夏祎旻，吴建群，杨松，等.燃煤电厂污染物脱除设备对PM2.5排放影响的研究进展[J].煤炭学报，2021,46(11):3645-3656.XIA Yimin,WU Jianqun,YANG Song,et al.Advances in the study of the effects of pollutant removal equipment on PM2.5 emissions in coal-fired power plants[J].Journal of China Coal Society,2021,46(11):3645-3656.
• [20] 吴建群.O2/CO2燃烧黄铁矿成灰机理及其对结渣影响规律的研究[D].武汉：华中科技大学，2019:83-92.