Influence of flue gas recirculation on deep peak regulation operation characteristics of 350 MW CFB boiler
WANG Jiaxing
PENG Jiansheng
LI Fan
HE Jianping
YANG Tianliang
DONG Yongsheng
WANG Shuai
Abstract：To solve the problems of fluidization safety and ultra-low NOx emission of supercritical CFB boiler under ultra-low load,flue gas recirculation technology was introduced.Taking a supercritical 350 MW CFB boiler as the research object,a flue gas recirculation auxiliary peak-shaving system after semi-dry desulfurization was built.Based on the data of field operation,the effects of operating parameters such as the average bed temperature,separator inlet temperature,exhaust temperature,NOx,CO mass concentration of outlet flue gas,combusti-ble content of fly ash and bottom ash,steam-water parameter at 30％-60％load were studied under the flue gas recirculation.The results show that under the coordination of flue gas recirculation,the final emission of NOx at 30％-60％load is less than 50 mg/m3 after SNCR,the original NOx emission is less than 50 mg/m3 at 30％load;the bed temperature is reduced by 15-22 ℃,the boiler exit flue temperature increases 10-13 ℃,and the primary and reheat steam temperature is above 558 ℃.With the decrease of boiler load,the carbon content of fly ash and bottom slag increases,and the mass concentration of CO does not increase significantly.The NOx is reduced about 15 mg/m3 by 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 heating surfaces is 55 and 47 ℃ respectively,and no over-temperature appears.
Keywords：supercriticalcirculating fluidized beddeep peak load regulationflue gas recirculationlow-NOx combustionNOx ultra-low emissionboiler operation characteristic
Publication Date：2024-09-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 68-76 )