余热锅炉对流受热面积灰特性的实验研究

Experimental Study on Ash Deposition Characteristic of Convection Heating Surface in Waste Heat Boiler

在模拟积灰实验台上研究了影响积灰的主要因素-浓度、风速、灰样特性和管束特性对余热锅炉积灰的影响规律。研究发现:灰粒在气流中浓度的不同仅仅影响积灰量达到稳定的时间。在烟气速度很低时,积灰量随着气流速度的增加而增加,当烟气速度大于5 m/s,积灰量随着烟气流速的增加而减小。灰样的粒径分布对积灰有着明显的影响,小颗粒灰粒更容易在管束的涡流区沉积下来,大颗粒灰粒很难沉积下来。管排特性对积灰的影响很明显,顺排管束时的积灰要比错排管束时严重;随着管束直径的增加,积灰量增加;在烟气流速很低时随着管束节距的增加,积灰量增加,在烟气流速达到5.7 m/s,随着管束节距的增加其积灰量逐渐减小。

The major factors effecting on the ash deposition, concentration of ash, gas velocity, ash feature and arrangement of tubes, have been investigated through the model experiment of ash deposition. It is discovered that the concentration of ash particles in gas only affects the relaxation time of reaching stable state, Under the condition of low gas velocity, the deposition quantity increases with gas velocity increasing, contrast to the condition that the gas velocity is higher than 5 in/s. The effect of ash diameters distribution on ash deposition is obvious, and small particles are easy to deposit in the eddy zone of tube bundle. In contrast, large particles are difficult to deposit. The arrangement style of tubes is important for ash deposition, and deposition of in-line arrangement is severer than that of staggered-arrangement. The deposition quantity increases with tube diameters increasing. Under the condition of low gas velocity the ash deposition increases with the tubes step, but gradually decreases after velocity reaching 5.7 m/s.