大型燃煤电站锅炉再热器热偏差的试验研究

Experimental Study on Thermal Deviation of Reheater in Large-Scale Coal-fired Utility Boiler

锅炉四角切圆炉膛出口存在的残余旋转,会形成水平烟道烟气流量的不均现象,使锅炉再热器产生较大的热偏差。结合湛江发电厂300MW机组锅炉的实际运行情况,对再热器热偏差问题进行了试验研究。试验结果显示,高温再热器入口处右侧的平均烟速比左侧高2m/s左右,右侧下排烟温高于上排100℃左右,再热器右侧出口汽温和壁温均大于左侧,造成再热器右侧超温。通过运行优化调整和设备改造,缓解了再热器两侧热偏差,减少了再热器超温。

Flue gas velocity deviation at the exit of furnace makes the flow of flue gas in level flue non-uniform, and makes a big temperature deviation in reheater. The thermal deviation in reheater was experimental studied in 300MW unit of Zhanjiang Power Station. The experimental results showed that the mean velocities of flue gas in the right part of the entrance of the high-temperature reheater was about 2m/s higher than those of the left part; and the lower ranks flue gas temperature is about 100℃ higher than the upper. Both of the steam temperature and metal wall temperature in the right reheater were higher than those in the left part, and it caused the overheating of the right reheater. The thermal deviation has been reduced through optimal operation adjustment and retrofit of reheater and burner.