600 MW超临界锅炉水冷壁高温腐蚀综合治理应用研究

Application Research on the Comprehensive Treatment for High Temperature Corrosion of Water-Cooled Wall of 600 MW Supercritical Boiler

针对某电厂600 MW超临界对冲燃烧锅炉水冷壁高温腐蚀的严重问题,提出了锅炉水冷壁高温腐蚀综合治理方案,对锅炉进行燃烧器及贴壁风改造。将中层(B、F)和下层(C、E)燃烧器更换为新型OPCC旋流煤粉燃烧器,同时在锅炉的两侧墙分别布置7层贴壁风。通过冷态动力场试验全面了解不同负荷工况及不同配风方式下的炉膛空气动力场分布,并优化了运行参数。在进行水冷壁高温腐蚀综合治理后,贴壁风覆盖区的水冷壁管厚度平均减薄量从2019年的2.52 mm/a下降到2020年的0.46 mm/a,较改造前高温腐蚀管壁减薄速度下降明显,且近壁区烟气含氧量大幅上升,H_(2)S浓度大幅下降,还原性气氛得到明显改善,可从根本上缓解水冷壁高温腐蚀。

Aiming at the high temperature corrosion of the water-cooled wall of a 600 MW supercritical opposed combustion boiler in a power plant,a comprehensive treatment plan for high temperature corrosion of the boiler water-cooled wall was proposed,and the boiler was modified with burners and closing-to-wall air.The middle layer(B,F)and lower layer(C,E)burners were replaced with new OPCC swirling pulverized coal burners,and seven layers of closing-to-wall air were arranged on both sides of the boiler.Through the cold dynamic field test,the aerodynamic field distribution of the furnace under different load conditions and different air distribution modes was fully understood,and the operating parameters were optimized.After the comprehensive treatment of high temperature corrosion of the water-cooled wall,the average thinning of the water-cooled wall tube thickness in the area covered by the closing-to-wall air decreased from 2.52 mm/a in 2019 to 0.46 mm/a in 2020.The thinning speed of the wall caused by high temperature corrosion decreases significantly compared with that before the transformation,and the oxygen content of the flue gas near the wall greatly increases,the H_(2)S concentration decreases significantly,and the reducing atmosphere is significantly improved,which can fundamentally alleviate the high temperature corrosion of the water-cooled wall.