再磨过程泵池液位区间与给矿压力模糊切换控制

Fuzzy Switching Control for Sump Level Interval and Hydrocyclone Pressure in Regrinding Process

赤铁矿再磨过程泵池液位受到大的随机干扰的影响,造成泵池液位波动大,采用已有的再磨过程泵池液位定值闭环控制方法,必然会造成矿浆泵转速在大范围内频繁变化,从而使给矿压力频繁波动在工艺规定的范围之外,降低了旋流器的分级效率.本文提出了由泵池液位区间控制和给矿压力回路控制组成的模糊切换控制方法,泵池液位区间控制通过对给矿压力设定值保持器和模糊补偿器的切换,将给矿压力设定值控制在所允许的波动范围内;通过给矿压力PI回路控制器跟踪其设定值,从而将泵池液位控制在目标值范围内,并将给矿压力的波动控制在允许的范围内.在国内某大型赤铁矿选矿厂的成功应用,表明采用该方法有效减少了泵池液位和给矿压力的波动,使得再磨过程安全运行,提高了旋流器分级效率.

In the mineral regrinding process of hematite beneficiation, the sump level （SL） fluctuates frequently due to some large disturbances. The pump speed inevitably changes in a wide range by adopting the existing setpoint control method for sump level, and the oscillations of hydrocyclone pressure （HP） can hardly be restricted in its desired range consequently. Hence, the classification efficiency of hydrocyclone is reduced remarkablely. In this paper, a two-layer hierarchical control structure based on fuzzy switching control method is proposed, which includes a switching controller of SL interval and a feedback controller of HP. By switching between a retainer of HP setpoint and a fuzzy compensator for HP setpoint, the controller of SL interval can guarantee the variations of HP setpoint within its desired range. In addition, the PI controller of HP can track its setpoint. Therefore, the sump level and the oscillations of HP can be limited in their target ranges respectively. The proposed method has been successfully applied to a large-scale domestic hematite beneficiation plant. The application results demonstrated that the fluctuations of SL and HP were significantly reduced. As a result, the safety operation of the regrinding process has been realized, and the improved classification efficiency of hydrocyclone has been achieved.