硅灰在对流管束表面沉积特性的试验研究

Experimental Research on the Deposition Characteristic of Silicon Powder on the Surface of Convection Tube Bundle

硅冶炼炉余热烟气中的硅灰在换热器表面沉积影响换热效率,研究了硅灰的基本粘结特性,及其在对流管束表面的沉积特性和清除方式。试验结果表明:硅灰的粘结性不强,主要在管壁迎风侧形成单侧楔形干松灰,虽然温度影响灰样的粒径分布,但管壁温度对硅灰的沉积和清除特性影响不大;越往烟气下游的受热面积灰越严重;存在临界烟气流速12 m/s,当烟气流速超过该值,增大流速不再有利于减轻积灰;钢珠清灰可高效地清除管壁积灰,而机械振打效果不佳。

Deposition of silicon powder on the surface of heat-recovery boiler tubes affects the heat exchange efficiency greatly. The basic cohesiveness of silicon powder, the deposition characteristic on the convection tube bundle and removal of deposition is presented. Results show that the cohesiveness of silicon powder is poor and the wedge-shaped deposition forms on windward side. Temperature affects the diameters profile of silicon powder, but tube wall temperature will not affect the powder depostion and removal largely. The deposition of downstream is more sever, and there is an critical flue gas velocity 12 m/s ,above which, the increase o f velocity wil not benefit the removal of deposition. In contrast with the low efficiency of mechanic vibration, the steel-ball can eliminate the deposition in high efficiency.