深锥沉降槽控制系统的研究与设计

Research and design of control system for deep-cone thickener

在铝矿石用碱稀释成铝酸钠溶液与赤泥混合物过程中,絮凝剂添加量过高或过低都将影响沉降速度和分离效率,分离的赤泥排放量影响靶机安全运行,因而絮凝剂添加量和底流排放需要控制在合理范围内。本文对深锥沉降槽沉降机理进行分析,基于深锥沉降槽物料平衡关系,考虑到絮凝剂、底流密度、泥位等对沉降速度的影响,建立了絮凝剂添加和底流控制模型。依据絮凝剂质量与进料料浆中固体质量成比例的关系,设计了絮凝剂开环控制结构;依据分离沉降槽控制工艺,分离沉降槽底流排放采用双闭环底流控制结构,内环底流密度控制采用常规PID结构,外环泥层高度控制采用模糊控制器结构;依据洗涤沉降槽洗涤工艺,洗涤沉降槽的底流密度控制采用常规PID结构:研究结果表明,该方法能够提高沉降槽的生产效率,降低系统能耗,保障系统可靠运行,沉降槽絮凝剂添加量和底流排放控制在应用中取得了很好效果。

In the process of alkali diluting aluminum ore,it produced mixture of sodium aluminate solution and red mud.Excessive or insufficient flocculants would affect sedimentation rate and separation efficiency,and the emission of red mud would affect rake safe,so the floeculants dose and undertow height should be controlled in proper range.The settlement mechanism of deep-cone thickener was analyzed,and flocculants adding and undertow control model were proposed based on material balance and effect of settlement velocity by flocculants,underflow density and mud position.According to the proportional relationship between flocculants quality and feed solids material,open loop control structure was established.According to control process of red mud separation thickener,double closed loop undertow control structure was established.The normal PID structure was used in inner underflow density loop,and fuzzy structure was used in outer mud height control.According to control process of red mud washing thickener,normal PID structure was used in red mud washing thickener＇s undertow density control.The research results show that this method can improve the production efficiency of thickener,and can reduce system consumption,also can ensure system operation reliable.The control of flocculates dose and undertow height were achieved good effect in application.