某超临界燃煤锅炉脱硝出口斜坡射流吹灰优化

Optimization of Jet Blowing on the Slope of the Denitrification Outlet of a Supercritical Coal-fired Boiler

某电站锅炉脱硝反应器出口斜坡处积灰严重,伴有设备磨损及烟道变形,严重影响了机组运行的安全性。斜坡处积灰中位径为123.91微米,远大于电除尘采集的飞灰。为解决烟道严重积灰的问题,在出口烟道长宽均为10m的区域加装阵列式射流吹灰器组,利用蒸汽射流强力扰动,定时对烟道进行吹灰,减轻积灰在烟道内沉降。烟道内流场模拟表明,50%负荷工况下,烟道内平均流速7.73m/s,比额定工况低51%;斜坡附近局部区域烟气平均流速8.39m/s,远低于额定工况的流速。单个射流吹灰器外直径0.2m处平均流速112m/s,流速大于50m/s区域,覆盖率65%,射流吹灰器组工作时能够对积灰产生有效扰动,因此,阵列式射流吹灰能够在实践过程消除斜坡积灰现象,提高了机组运行的安全性。

A power station boiler denitrification reactor outlet ramp was characterized by serious ash accumulation,accompanied by equipment wear and flue deformation,which seriously affects the safety of the unit operation.The median diameter of ash accumulation at the slope is 123.91μm,which is much larger than the fly ash collected by electrostatic precipitation.In order to solve the problem of serious ash accumulation in the flue,an array jet soot blower group is installed in the area where the length and width of the outlet flue are 10m,and the strong disturbance of the steam jet is used to blow the soot on the flue at regular intervals to reduce the settlement of ash in the flue.The simulation of the flow field in the flue shows that the average flow velocity in the flue is 7.73m/s under the 50%load condition,which is 51%lower than the rated condition.The average flue gas velocity in the local area near the slope is 8.39m/s,which is much lower than the flow velocity under the rated working conditions.The average flow velocity at the outer diameter of 0.2m of a single jet soot blower is 112m/s.The coverage rate is 65%in the area with flow rate more than 50m/s.The jet sootblower group can effectively disturb the ash accumulation.Therefore,the array jet sootblowing can eliminate the slope ash accumulation phenomenon in the practice process and improve the safety of the unit operation.