中速磨煤机风环动静间隙对石子煤排放的影响

石子煤排放率是影响中速磨煤机安全经济运行的一个重要参数。磨煤机风环动静间隙会随着磨损而增大,使风环出口风速降低,导致石子煤排放增加。以HP863型磨煤机实测结构参数及其石子煤物性分布为基础,采用数值模拟的方法研究了风环动静间隙对石子煤排放的影响。结果表明,风环动静间隙的大小对风环出口风速的影响十分明显,动静间隙从10 mm磨损至20 mm,在65 t/h的总风量下风环出口风速降低10.2 m/s,石子煤总沉降率增加了114%。提出了一个动静间隙防漏风的优化方案,在风环动静间隙由10 mm磨损到20 mm,石子煤总沉降率比优化前下降31%。实际磨煤机风环结构改造后,石子煤排放率降低了68.7%,达到了相关标准要求,已运行近2 a,没有再出现石子煤排放率增加现象,原存在的石子煤排放量过大制约磨煤机出力的问题得到了有效解决。

Influence of ring nozzle rotation clearance on gangues discharge of medium speed mill

The ratio of gangues discharge is one of important parameters,which affect the safety and economy of medium speed mill operation.The rotation clearance will increase by wear,which would reduce ring nozzle outlet air velocity and increase gangues discharge.The influence of ring nozzle rotation clearance on gangues discharge was studied by numerical simulation based on actual mill structure and gangues physical property.The results showed that the effect of rotation clearance on ring nozzle outlet air velocity was obvious.The outlet air velocity would reduce 10.2 m/s and the ratio of gangues deposition would increase 114% when rotation clearance increased from 10 mm to 20 mm at 65 t/h total air volume.One rotation clearance optimization scheme was proposed in order to reduce air escape when the rotation clearance was increased by wear.When the rotation clearance was increased from 10 mm to 20 mm,the gangues deposition would reduce 31% compared with the case before optimization.After the practical improvement,the ratio of gangues discharge was reduced 68.7% and had met the standard requirements without any increasing trend in nearly two years.The problem of insufficient output caused by gangues discharge was also solved effectively.