350MW燃煤机组脱硝装置喷氨优化调整及其缺陷分析

Optimization Adjustment and Defect Analysis of Ammonia Injection of Denitrification Unit in 350 MW Coal-Fired Unit

按照国家环保要求(燃煤发电机组脱硝装置出口NOx质量浓度≤50 mg/m^(3)),对某350 MW燃煤机组手动调节阀门开度进行喷氨优化调整。优化调整后,A侧和B侧出口折算NOx质量浓度均值分别为23.3 mg/m^(3)(标准状态、干基、6%O2)和35.1 mg/m^(3)(标准状态、干基、6%O2),满足排放标准,喷氨量分别降低13.1 m3/h和17.1 m3/h,氨逃逸分别降低0.78×10^(-6)和1.09×10^(-6);但调整前后同一测点平面不均匀度未有明显改善,相对高值和相对低值的位置不变。经分析,出现这种情况与脱硝装置的系统缺陷有关,建议电厂停机期间更换喷氨管道调节阀,检查喷氨分配管腐蚀情况及催化剂组块间密封情况,定期进行催化剂活性测试,发现问题及时消除。建立物理模型试验或者数值模型模拟,确定科学的导流板安装位置,优化烟气测量装置和控制逻辑,整体提升脱硝装置性能。

Ammonia injection is optimized and adjusted for a 350 MW coal-fired generating unit in accordance with the national environmental protection requirements(NOx mass concentration of denitration export of coal-fired generating unit≤50 mg/m^(3)).After the optimization and adjustment of ammonia injection of denitrification unit,the average mass concentration of converted NOx at the exit of side A and side B is 23.3 mg/m3(standard state,dry base,6%O2)and 35.1 mg/m^(3)(standard state,dry base,6%O2)respectively,which meet the emission standards,and the ammonia injection volume is reduced by 13.1 m^(3)/h and 17.1 m^(3)/h,respectively.Ammonia escape decreased by 0.78×10^(-6) and 1.09×10^(-6),respectively.However,the unevenness of the same measuring point plane has been not improved significantly before and after adjustment,and the positions of relatively high and relatively low values remained unchanged.It is suggested that during the shutdown period of the power plant,the regulator of ammonia injection pipeline should be replaced,the corrosion of ammonia injection distribution pipe should be checked,the sealing situation between catalyst blocks should be checked,and the catalyst activity test should be conducted regularly.If problems are found,the deficiency should be eliminated in time.Establish physical model test or numerical model simulation,optimize and determine the scientific installation position of the guide plate,optimize the smoke measuring device and control logic,and improve the denitration device performance as a whole.