第37卷第4期 2010年7月
华北电力大学学报
Jourmal of North China Electric Power University
煤质劣化对锅炉热量分配影响的机理分析
张，田亮，付恩狄，刘吉臻
（华北电力大学控制与计算机工程学院，河北保定071003）
Vol. 37, No. 4 Jul.2010
摘要：受能源供应紧张影响电厂经常燃用劣质煤，其主要特点是灰分、水分大而发热量低，以此特征为基础建立一种煤质劣化模型。利用炉内传热相似理论求解方法，以一300MW燃煤机组炉腔结构设计为例分析了不同劣化程度的煤质对锅炉主要设计参数造成的影响。计算结果表明：随煤中水分和灰分增加单位辐射热量降低，并且水分的影响大于灰分：随煤灰分增加单位辐射热量与单位对流热量之比升高，但随水分增加而降低。高负荷时，随煤中水分和灰分增加炉腹出口烟温略微降低；低负荷时，随煤中灰分增加炉睦出口烟温略微降低，而随煤中水分增加略微升高。
关键词：燃煤锅炉；煤质劣化；热量分配；炉腔出口烟温
中图分类号：TK222
文献标识码：A
文章编号：10072691（2010）04006705
Analysisinfluencemechanismofcoalqualitydeterioration
toboilerheatdistribution
ZHANG e, TIAN Liang , FU En -di , LIU Ji - zhen
(School of control and Computer Engineering, North China Electric Power University, Baoding 071003, China) Abstract: Power plants often use inferior coal due to shortage of energy supply. The main characteristies of poor-grade coal are large content of ash, moisture and low calorific. Based on its features, a model of coal quality deterioration was established. This paper mainly analyzed the impact of different degrees of coal quality deterioration on main param-eters design of boiler with the fumace heat transfer theory method , with the example of furmace structure design of 300 MW coal-fired unit. The result shows that : unit radiation heat reduces as moisture and ash content in coal increase and the impact of moisture is greater than ash; with the ash increasing in coal, the unit ratio radiation heat increases with u-nit convection heat, but it reduces with moisture increasing in coal. At high load, with the moisture and ash increasing in coal, the gas temperature of furmace outlet lows slightly; At low load, with the ash increasing in coal, the flue gas temperature of fumace outlet reduces slightly, but with moisture increasing in coal , it rises slightly.
Key words: coal-fired boiler; coal quality deterioration; heat distribution ; the flue gas temperature of furnace outlet
对锅炉的安全经济性产生较大的影响。上述三种
引言 0
目前能源供应处于相对紧张的状态，电厂来煤得不到保证，大多数电厂燃用劣质煤）：近几年有些电厂在进行锅炉的设计时，套用具有相同煤质锅炉的结构特性参数，在锅炉制造，安装等环节出现许多误差；锅炉长期运行后出现机械磨损，设备老化等。这些都会影响锅炉的燃烧工况，
收稿日期：200912-10
基金项目：国家863项目（2007AA04Z163）。
情况中，由于煤质偏离设计标准在实际电厂的情况尤为突出，会导致锅炉燃烧不稳定，炉膛温度偏离设计值，单位辐射热量降低，排烟损失增加，锅炉效率降低，影响机组的安全稳定运行2}。其中由于灰分水分较高对系统产生的最重要影响参数是炉膛出口烟温，因为炉膛烟气温度影响炉膛出口处的对流受热面的结渣。同时在工质侧，基本上是区分炉膛水冷壁内蒸发吸热和过热器内蒸汽的过热吸热的界限；在烟气侧炉腔出口烟温是区分锅炉烟气侧的炉内辐射传热和对流烟道内