Yantai Longyuan Power Technology Co.,Ltd.
School of Energy Science and Engineering,Harbin Institute of Technology
Shenhua Shendong Electric Power Shanxi Hequ Power Generation Co.,Ltd.

为解决超临界CFB锅炉超低负荷时流化安全性及NOx超低排放,引入烟气再循环技术,以某电厂超临界350MWCFB锅炉为研究对象,搭建了循环半干法脱硫后烟气的再循环辅助调峰系统,基于运行实测数据,研究该锅炉在30%~60%负荷率下烟气再循环对平均床温、分离器入口温度、排烟温度、炉膛出口烟气NOx、CO质量浓度、飞灰及底渣可燃物含量、汽水参数等运行参数的影响,试验结果表明:烟气再循环协同下,30%~60%负荷SNCR脱硝后NOx最终排放小于50mg/m3,30%负荷实现锅炉原始NOx超低排放;床温降低15~22℃,炉膛出口烟温提高10~13℃,主再热汽温在558℃以上;随锅炉负荷降低,飞灰及底渣含碳量升高,CO质量浓度未见大幅增加;40%负荷炉膛二次风SNCR脱硝NOx降幅约15mg/m3;负荷上升/下降变化最小速率1.23%Pe;30%负荷及以上保持干态运行,水冷壁壁温最大偏差55℃,屏过及屏再最大壁温差分别55、47℃,均未出现壁温超温。

To solve the problems of fluidization safety and ultra-low NO emission of supercritical CFB boiler under ultra-low load,flue gasrecirculation technology was introduced. Taking a supercritical 350 MW CFB boiler as the research object,a flue gas recirculation auxiliarypeak-shaving system after semi-dry desulfurization was built. Based on the data of field operation,the effects of operating parameters suchas the average bed temperature,separator inlet temperature,exhaust temperature,NO,CO mass concentration of outlet flue gas,combustible content of fly ash and bottom ash,steam-water parameter at 30%-60% load were studied under the flue gas recirculation. The resultsshow that under the coordination of flue gas recirculation,the final emission of NO at 30%-60% load is less than 50 mg/ m after SNCR,the original NO emission is less than 50 mg/ m at 30% load; the bed temperature is reduced by 15-22 ℃ ,the boiler exit flue temperatureincreases 10-13 ℃ ,and the primary and reheat steam temperature is above 558 ℃ . With the decrease of boiler load,the carbon content offly ash and bottom slag increases,and the mass concentration of CO does not increase significantly. The NO is reduced about 15 mg/ mby SNCR arranged at secondary air; the minimum change rate of load rise/ fall is 1.23% Pe; the boiler keeps dry operation above 30%load,the maximum deviation of water wall temperature is 55 ℃ at 30% load,the maximum deviation of overheated and reheated heatingsurfaces is 55 and 47 ℃ respectively,and no over-temperature appears.

国家重点研发计划资助项目(2022YFB4100302)

王家兴,彭建升,李凡,等.烟气再循环对350MWCFB锅炉深调运行特性影响[J].洁净煤技术,2024,30(9):68-76.

WANG Jiaxing,PENG Jiansheng,LI Fan,et al.Influence of flue gas recirculation on deep peak regulation operation characteristics of 350 MW CFB boiler[J].Clean Coal Technology,2024,30(9):68-76.