Emission characteristics and controlling of NOx in lean coal-fired boiler of the 330 MW unit
YANG Wei
LI Wenxiu
GUO Fude
YANG Fengling
ZHANG Kai
CHENG Fangqin
Abstract：The field experiments of low-NOx combustion system were conducted in a 330 MW lean coal-fired boiler.Testing investigation of NOx emissions was performed before and after furnace exit and SCR.At the same time,the concentration of NOx varying with the depth of the tail flue and boiler load was examined.The results show that concentration of NOx in the furnace outlet is maintained about 600 mg/m3.The concentration of NOx is related to the sampling location,thus the stationing of section in the field test should be reasonable.The emission of NOx will be less than 50 mg/m3 under the different load with the control of low-NOx and SCR.The denitration efficiency of the SCR system is good under normal running condition.However,there are some problems,such as large consumption of ammonia,catalyst blockage,abrasion and low-NOx efficiency at low load.The study suggests that the power generation unit should combine SNCR with SCR,and increasing the residence time of the ammonia in the system can improve the denitration efficiency and avoid ammonia escaping.
Keywords：lean coalSCRNOx emissionslow-NOx combustion
Publication Date：2017-01-01