W型锅炉SCR脱硝装置积灰原因分析与治理

某电厂W型火焰锅炉燃用高灰分无烟煤，SCR脱硝反应器催化剂、导流板、整流格栅、支撑钢梁积灰严重，造成了流场不均匀和催化剂堵塞，影响了SCR脱硝系统的性能。根据运行经验和CFD技术，分析得出SCR脱硝装置积灰的原因是设计不合理、催化剂选型不合理、流场不均、吹灰效果不佳、长期低负荷运行和燃煤灰分远超设计值。通过采用烟气流场优化及1∶10物理模型试验，对导流板、整流格栅和顶部烟道进行了改造，同时将蜂窝式催化剂更换为板式催化剂，加装声波吹灰器。改造后运行3个月，对脱硝装置进行内部检查，反应器水平烟道、导流板积灰明显减少，整流层未见积灰，催化剂表面和孔隙无积灰、堵塞现象，证明所采取的各项措施有效解决了SCR反应器内积灰、催化剂堵塞问题。

Analysis and Treatment of Ash Deposition in SCR Denitration Equipments of W Boiler

The W type flame boiler in a power plant is burned with high ash anthracite. The serious ash accumulation on the SCR denitrification reactor catalyst, the diversion plate, the rectifying grille and the supporting steel beam can lead to the uneven flow of the flow field and the blockage of the catalyst, which affects the performance of the SCR denitrification system. According to the operation experience and the CFD technology, the reasons for the ash accumulation in the SCR denitrification devices are improper design, unreasonable catalyst type selection, uneven flow field, poor soot blowing, long term low load operation and coal ash far beyond the design value. Based on the optimization of the flue gas flow field and the 1︰10 physical model test, the diversion plate, the rectifying grid and the top flue were reformed; the honeycomb type catalyst was replaced by the plate type catalyst; and the sonic soot blower was added. Three months after the transformation, the internal inspection of the denitrification devices was carried out. The horizontal flue of the reactor and the ash accumulation of the diversion plate were reduced obviously. No ash accumulation was found in the rectifying layer. No accumulated ash and blockage were found on the surface of the catalyst and the. It is proved that the measures taken have solved the problem of the internal dust accumulation and the catalyst plugging in the SCR reactor effectively.