600 MW对冲燃烧锅炉分磨掺烧煤粉燃尽特性的模拟和试验研究  

Simulation and experimental study on the burnout characteristics of pulverized coal in a 600 MW opposed combustion boiler by mixing grinding and burning

作　　者：彭昭雄 刘兵兵 范多文 刘磊[2] 刘小伟[2] PENG Zhaoxiong;LIU Bingbing;FAN Duowen;LIU Lei;LIU Xiaowei(China Huadian Co.,Ltd.,Sichuan Company,Guang’an 638017,China;National Key Laboratory of Coal Combustion and Low Carbon Utilization,School of Power and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]中国华电集团四川广安发电有限责任公司,四川广安638017 [2]华中科技大学能源动力与工程学院煤燃烧与低碳利用全国重点实验室,湖北武汉430074

出　　处：《热力发电》2024年第1期175-182,共8页Thermal Power Generation

基　　金：国家基金委联合基金重点项目(U22A20211)。

摘　　要：针对亚临界600 MW自然循环对冲燃烧锅炉燃用3种差异性较大的煤种,通过数值模拟结合现场试验研究了分磨配煤掺烧对降低飞灰含碳量的作用机制,建立了对冲锅炉分层燃烧混煤的燃料特性与燃尽率、飞灰含碳量的关联性,并提出了改善电站锅炉中煤粉燃尽特性的配煤原则。首先设定了3种极端的工况,以优质煤为主分别集中在燃烧器的上、中、下3层燃烧器中进行燃烧;再通过计算流体动力学(computational fluid dynamics,CFD)模拟发现优质煤在上层燃烧器分布且劣质煤在下层分布时,劣质煤在炉内的停留时间显著增加,其在上层高温区充分燃烧,飞灰含碳量低。同时,根据不同工况下各层燃烧器煤粉的热值、挥发分、灰分进行分析,发现热值差异性是影响其燃尽特性的主要影响因素;然后基于燃煤电厂实际运行条件,设置了更切合实际的配煤工况,并进行了数值模拟与现场试试验研究,发现各工况下呈现的煤粉总体燃尽特性符合上述规律,飞灰含碳量相比于电厂原始运行工况下降。最后得到配煤原则为:在充分考虑电厂实际运行条件的情况下,将高热值的煤种向中、上层燃烧器布置,而低热值的煤种向中、下层燃烧器分布。In order to explore the effects of mixed coal combustion on reducing the carbon content of fly ash in a subcritical 600 MW natural circulation balanced draft boiler,three types of coal with significant differences in characteristics were used,and numerical simulations were combined with experiments to study the mechanism of mixed coal combustion and its relationship with fuel characteristics,burnout rate,and carbon content in fly ash in the stratified combustion process of the balance boiler.Based on the results,a set of coal blending principles are proposed to improve the combustion characteristics of coal powder in power station boilers.Firstly,three extreme operating conditions were set up,and high-quality coal was respectively focused on the upper,middle,and lower layers of the burner for combustion.And then,through computational fluid dynamics(CFD)simulations,it was found that when the coal powder airflow of the balance combustion boiler flowed upward,and the high-quality coal was distributed in the upper layer of the combustion chamber while the poor-quality coal was distributed in the lower layer,the residence time of poor-quality coal in the furnace increased significantly,allowing it to fully combust in the high-temperature area of the upper layer,resulting in a low carbon content in fly ash.Furthermore,based on the analysis of the heat value,volatile matter and ash content of coal powder in different combustion layers under various working conditions,it was found that the difference in heat value and ash content is the main factor influencing combustion characteristics.Based on the actual operating conditions of the coal-fired power plant,a more realistic set of coal blending scenarios was established,and numerical simulations and on-site experiments were conducted,which showed that the overall combustion characteristics of coal powder under each working condition followed the aforementioned rules,and the carbon content in the fly ash reduced compared with the original operating conditions.Finally,the c

关 键 词：燃煤锅炉 配煤掺烧 煤质 燃尽率 飞灰含碳量 

分 类 号：TM621.2[电气工程—电力系统及自动化]