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浙江大学学报(工学版)
浙江大学学报(工学版)  2019, Vol. 53 Issue (2): 220-227    DOI: 10.3785/j.issn.1008-973X.2019.02.003
能源工程     
碗式配风对燃烧效率与NOx质量浓度的影响
谢晓强1(),杨建国1,*(),朱朝阳2,刘川槐2,赵虹1,王智化1
1. 浙江大学 能源清洁利用国家重点实验室，浙江 杭州 310027
2. 淮浙煤电有限责任公司凤台发电分公司，安徽 淮南 232131
Effect of bowl-shaped secondary air distribution on combustion efficiency and NOx mass concentration
Xiao-qiang XIE1(),Jian-guo YANG1,*(),Chao-yang ZHU2,Chuan-huai LIU2,Hong ZHAO1,Zhi-hua WANG1
1. State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
2. Fengtai Power Generation Branch of Huaizhe Coal and Power Co. Ltd, Huainan 232131, China
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摘要：

对600 MW超临界前后墙对冲燃烧锅炉在均等配风和碗式配风下的燃烧进行数值模拟，分析不同偏差程度碗式配风对炉内颗粒质量浓度场、CO体积分数场、炉膛温度、NOx生成的影响，并与试验结果进行对比. 模拟结果表明，燃烧器碗式配风改善了炉内宽度方向上的风、煤混合过程，减小了CO体积分数和煤粉颗粒质量浓度偏差，降低了炉膛出口烟气中CO的平均体积分数和飞灰中碳的质量分数，从而有效提高了前后墙对冲燃烧锅炉的燃烧效率. 燃烧器碗式配风对炉膛出口烟气中NOx的平均质量浓度有不利影响，但是当碗式配风风量偏差不大于20%时，NOx平均质量浓度变化不大于3.5%. 综合燃烧器碗式配风对水平截面CO分布特征和炉膛出口烟气中NOx的平均质量浓度的影响，在燃烧常用煤种的条件下，碗式配风的风量偏差宜控制在20%以内. 炉膛出口烟气中CO的平均体积分数、飞灰中碳的质量分数、NOx平均质量浓度的模拟值与热态试验值变化趋势一致. 在实际应用中碗式配风对CO平均体积分数的降低效果更加显著，当碗式配风的风量偏差达到20%时，省煤器出口烟气中CO的平均体积分数降低幅度达95%.
关键词： 锅炉;  前后墙对冲燃烧;  碗式配风 (BSAD);  CO体积分数;  碳质量分数;  NOx质量浓度    
Abstract:

The combustion process in a 600 MW supercritical opposite-wall-firing boiler under the conditions of equal and bowl-shaped secondary air distribution (BSAD) was numerically simulated. The influence of varying secondary air distribution deviation on the particle mass concentration field, CO volume fraction field, furnace temperature and NOx generation was analyzed. The calculated results were compared with experimental data. The simulation results showed that BSAD enhanced the mixing between pulverized coal and air, decreased the bias of average CO volume fraction and particle mass concentration along the furnace width, reduced the average CO volume fraction in flue gas, carbon mass fraction in fly ash at the furnace exit, and improved the combustion efficiency of opposite-wall-firing boiler. BSAD did harm to the average NOx mass concentration in flue gas at the furnace exit, however, the NOx mass concentration varied within 3.5% when the deviation of the secondary air distribution was less than 20%. By combining the effects of BSAD on horizontal CO volume fraction distribution and average NOx mass concentration in flue gas at the furnace exit, the appropriate deviation of BSAD for the boiler is recommended to be 20% when the boiler utilizes frequently-fired coal. The variation trend of numerical results of average CO volume fraction in flue gas, carbon mass fraction in fly ash, average NOx mass concentration at the furnace exit is consistent with the in-situ experimental results. In practical operation, the effect of BSAD on declining average CO volume fraction is more significant, the reduction of average CO volume fraction at the economizer exit reaches 95% when the deviation of secondary air distribution equals to 20%.
Key words: boiler    opposite-wall-firing    bowl-shaped secondary air distribution (BSAD)    CO volume fraction    carbon mass fraction    NOx mass concentration
收稿日期: 2018-01-01 出版日期: 2019-02-21
CLC:  TK 224  
通讯作者: 杨建国     E-mail: xiexiaoqiang@zju.edu.cn;yjg@zju.edu.cn
作者简介: 谢晓强（1991—），男，博士生，从事前后墙对冲燃烧锅炉燃烧优化技术研究. orcid.org/0000-0001-8834-354X. E-mail: xiexiaoqiang@zju.edu.cn
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引用本文:

谢晓强,杨建国,朱朝阳,刘川槐,赵虹,王智化. 碗式配风对燃烧效率与NOx质量浓度的影响[J]. 浙江大学学报(工学版), 2019, 53(2): 220-227.

Xiao-qiang XIE,Jian-guo YANG,Chao-yang ZHU,Chuan-huai LIU,Hong ZHAO,Zhi-hua WANG. Effect of bowl-shaped secondary air distribution on combustion efficiency and NOx mass concentration. Journal of ZheJiang University (Engineering Science), 2019, 53(2): 220-227.

链接本文:

http://www.zjujournals.com/eng/CN/10.3785/j.issn.1008-973X.2019.02.003    或    http://www.zjujournals.com/eng/CN/Y2019/V53/I2/220

工业分析wB/% Q/（MJ·kg?1） 元素分析wB/%
M A V C H O N S
7.00 26.00 26.13 21.30 56.37 3.72 5.54 1.00 0.37
表 1  锅炉燃用煤的工业分析与元素分析（收到基）
图 2  低NOx旋流燃烧器HT-NR3结构示意图
名称 qm /（kg·s?1） θa / °C r/%
一次风 133.4 75 23.00
内二次风 62.8 345 10.83
外二次风 267.8 345 46.17
燃尽风 116.0 345 20.00
表 2  额定工况下锅炉主要运行参数
工况 配风方式 D/%
中间燃烧器 两侧燃烧器
1 均等配风 0 0
2 10%碗式配风 ?5 +5
3 20%碗式配风 ?10 +10
4 30%碗式配风 ?15 +15
表 3  不同碗式配风工况下燃烧器外二次风的风量分配
图 1  锅炉炉膛结构及燃烧器、燃尽风喷口布置
截面 H/m 截面位置说明
Z1 17.5 冷灰斗与水冷壁衔接位置
Z2 19.9 第1层燃烧器中心
Z3 24.9 第2层燃烧器中心
Z4 29.8 第3层燃烧器中心
Z5 32.5 燃烧器区域出口
Z6 36.8 主燃尽风中心
Z7 42.5 燃尽风区域出口
表 4  炉膛横向截面位置说明
图 3  沿炉膛高度方向上不同截面平均温度实测值与模拟值的比较
图 5  碗式配风对燃尽风区域出口处CO体积分数场的影响
图 6  碗式配风对燃烧器区域出口处颗粒质量浓度场的影响
图 7  碗式配风对燃尽风区域出口处颗粒质量浓度场的影响
图 8  沿炉膛高度方向上不同截面CO平均体积分数变化
配风方式 $\overline \varphi_{\rm s}\left({\rm O}_2\right)$/
% 		$\overline \varphi_{\rm s}\left({\rm CO}\right)$/
% 		$w_{\rm s}\left({\rm C}\right)$/
% 		$\overline \rho_{\rm s}\left({\rm NO}_x\right)$/
（mg·m?3）1)
注：1）NOx质量浓度折算到6%O2体积分数
均等配风 2.17 0.435 6 3.27 314
10% 碗式配风 2.21 0.404 4 3.47 312
20% 碗式配风 2.08 0.285 6 2.21 325
30% 碗式配风 1.94 0.230 9 1.38 388
表 5  不同配风方式下炉膛出口烟气参数模拟值
图 9  沿炉膛高度方向上不同截面平均烟气温度变化
图 10  沿炉膛高度方向上不同截面NOx平均体积分数变化
图 4  碗式配风对燃烧器区域出口处CO体积分数场的影响
配风方式 $\overline \varphi_{\rm t}\left({\rm O}_2\right)$/
% 		$\overline \varphi_{\rm t}\left({\rm CO}\right)$/
% 		$w_{\rm t}\left({\rm C}\right)$/
% 		$\overline \rho_{\rm t}\left({\rm NO}_x\right)$/
（mg·m?3）1)
注：1）NOx质量浓度折算到6%O2体积分数
均等配风 2.10 0.232 4 3.34 302
10% 碗式配风 2.06 0.064 1 2.89 326
20% 碗式配风 2.01 0.012 0 2.14 306
表 6  不同配风方式下省煤器出口烟气参数试验值
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