Industrial-scale investigations on effects of tertiary-air declination angle on combustion and steam temperature characteristics in a 350-MW supercritical down-fired boiler  

作　　者：Xiaoguang LI Lingyan ZENG Hongye LIU Yao LI Yifu LI Yunlong ZHAO Bo JIAO Minhang SONG Shaofeng ZHANG Zhichao CHEN Zhengqi LI 

机构地区：[1]School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150001,China [2]Guizhou Wanfeng Electric Power Co.,Ltd.,Xingyi 562400,China [3]Guizhou Xingyi Project Department,Huadian United(Beijing)Power Engineering Co.,Ltd.,Xingyi 562400,China

出　　处：《Frontiers in Energy》2021年第1期132-142,共11页能源前沿（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.51706054);the China Postdoctoral Science Foundation(Grant No.2019M660633).

摘　　要：Industrial-scale experiments were conducted to study the effects of tertiary air declination angle(TDA)on the coal combustion and steam temperature characteristics in the first 350-MW supercritical down-fired boiler in China with the multiple-injection and multiple-staging combustion(MIMSC)technology at medium and high loads.The experimental results indicated that as the TDA increased from 0°to 15°,the overall gas temperature in the lower furnace rose and the symmetry of temperature field was enhanced.The ignition distance of the fuel-rich coal/air flow decreased.In near-burner region,the concentration of O2 decreased while the concentrations of CO and NO increased.The concentration of NO decreased in near-tertiary-air region.The carbon in fly ash decreased significantly from 8.40%to 6.45%at a load of 260 MW.At a TDA of 15°,the ignition distances were the shortest(2.07 m and 1.73 m)at a load of 210 MW and 260 MW,respectively.The main and reheat steam temperatures were the highest(557.2℃ and 559.4℃ at a load of 210 MW,558.4℃ and 560.3℃ at a load of 260 MW).The carbon in fly ash was the lowest(4.83%)at a load of 210 MW.On changing the TDA from 15°to 25°,the flame kernel was found to move downward and the main and reheat steam temperatures dropped obviously.The change of TDA has little effect on NO_(x) emissions(660–681 mg/m^(3) at 6%O_(2)).In comprehensive consideration of the pulverized coal combustion characteristics and the unit economic performance,an optimal TDA of 15°is recommended.

关 键 词：supercritical down-fired boiler industrialscale experiment tertiary air declination angle coal combustion steamtemperature 

分 类 号：TK229.6[动力工程及工程热物理—动力机械及工程]