飞灰复燃对炉内颗粒沉积状况的影响分析

实际工程表明,采用飞灰复燃技术对锅炉进行改造,可以减少飞灰所带走的燃料损失,提高锅炉效率,但飞灰回收复燃给壁面颗粒沉积状况也带来了影响.采用FLUENT模拟了SZL15-1.25-AⅡ型双筒链条蒸汽锅炉炉内燃烧,对比分析了采用飞灰复燃技术前后炉内壁面颗粒沉积状况.模拟结果表明,飞灰复燃对锅炉顶墙、前墙及后墙的颗粒沉积速率影响较大,其中飞灰复燃提高了顶墙和前墙的颗粒沉积速率,降低了后墙颗粒沉积速率,而对锅炉前后拱的影响很小可以忽略.减小飞灰入射质量流量或调整飞灰入射角度为水平偏下,均可以降低颗粒在水冷壁的沉积速率,有利于炉膛与水冷壁间的传热.

Analysis of effects of fly ash reburning to particle deposition in boiler

The results of the actual project show us that the fly ash reburning technology can reduce the loss of fuel taken away by the fly ash and improve the efficiency of the boiler,but at the same time the recycling of the fly ash can also affect the conditions of the deposition of the particles on the wall.In this paper boiler with and without the fly ash reburning technology were analyzed respectively using the CFD numerical simulation and the difference of the deposition conditions were compared.Simulation results show that the fly ash reburning technology affect the particle deposition rate much largely on the top wall,front wall and back wall of the boiler.The deposition rate becomes higher than before on the top wall and front wall,but it becomes lower on the back wall.The influence of the technology on the deposition rate could be ignored on the arch of the boiler.Reduce the incidence flow of fly ash can reduce the particle deposition rate on the wall and advantageous to the heat transfer between the furnace and the water wall.