赤铁矿磨矿全流程智能控制系统的研究

发布时间：2018-04-05 20:50

  本文选题：赤铁矿磨矿过程　切入点：磨矿粒度　出处：《东北大学》2015年博士论文

【摘要】：我国赤铁矿资源丰富,但大部分赤铁矿存在品位低、矿物组成复杂、铁矿物比磁化系数低、有用矿物嵌布粒度粗细不均、矿物之间共生紧密的特点,普遍采用一段球磨机与螺旋分级机、二段球磨机与旋流器构成的两段闭路磨矿过程,其首要任务是将磨矿产品粒度指标(常以-200目百分含量表示,%200mesh)控制在工艺规定的目标值范围内,使得有用矿物与脉石单体充分解离,为后续选别工序提供粒度合格的矿浆；同时应将球磨机负荷控制在最佳点附近,提高球磨机处理量,提高磨矿效率。因此,实现磨矿过程全流程的控制对于选矿生产指标的提高、降低能源消耗都具有重要的现实意义。由于我国赤铁矿磨矿工艺流程不同于国外普遍采用的一段棒磨机开路磨矿、二段球磨机与水力旋流器闭路磨矿流程,是一个具有综合复杂性的冶金工业过程,主要表现在：1、赤铁矿磨矿过程由两段连续闭路磨矿组成,工艺流程较长,影响磨矿产品粒度指标的操作因素较多,如球磨机的给矿量、球磨机入口加水量、螺旋分级机溢流浓度、旋流器给矿浓度等工艺参数,并且赤铁矿中的强磁性颗粒存在“磁团聚”现象,使得在线粒度检测仪表难以真实测量磨矿粒度指标,因此难以采用常规控制方法实现该过程的运行反馈控制,在实际生产过程中广泛采用人工手动控制方式根据磨矿粒度的化验值凭经验调整基础控制回路的设定值,然而由于人工化验周期较长,无法实时对磨矿生产过程进行指导,导致磨矿粒度波动范围大,无法为选别工序提高粒度合格的矿浆；2、赤铁矿原矿性质频繁波动使得一段磨矿过程存在较大的不确定性,易造成球磨机负荷工作点发生漂移,使其工作在“欠负荷”或“过负荷”故障工况,严重时发生球磨机“涨肚”或“空砸”等事故,影响磨矿过程的安全稳定运行；3、国外普遍采用定量给矿、配比给水的棒磨机开路磨矿为再磨过程提供粒度合格的矿浆,由于矿浆流量稳定,采用闭环定值控制方法即可实现对再磨过程泵池液位的控制,而不会造成旋流器给矿压力的较大波动；而赤铁矿一段球磨机与螺旋分级机的闭路磨矿过程矿浆流量波动较大,并且泵池液位受到污水、冲洗水等随机干扰的影响,导致再磨过程泵池液位发生频繁较大波动,如果采用常规设定值闭环控制方式则需要较大改变矿浆泵转速,导致旋流器给矿压力发生较大波动,影响旋流器分级效率,因此常规闭环定值控制方法难以应用于赤铁矿再磨过程。综上所述,必须结合我国赤铁矿磨矿过程的生产实际,开发出适应我国赤铁矿磨矿过程的基础回路控制方法和全流程运行反馈控制方法,对于提高磨矿产品质量、提高磨矿效率、降低能源消耗都有着重要的现实意义。本文依托国家重点基础研究发展计划(973)重点课题“复杂生产制造全流程一体化控制系统整体控制策略与运行控制方法”(编号：2009CB320601),提出了在以磨矿粒度指标和球磨机负荷为控制目标的赤铁矿磨矿全流程控制策略,开展了赤铁矿磨矿全流程运行反馈控制与再磨过程基础回路控制方法的研究,并在此基础上设计和开发了赤铁矿磨矿过程智能控制软件,同时结合“酒钢选矿厂综合自动化系统”改造项目,进行了赤铁矿磨矿全流程智能控制系统软、硬件结构设计、安装、调试、工业实验并投入运行,取得如下成果：1、针对赤铁矿磨矿过程生产工艺特点和具有的综合复杂特性,提出了将两段连续闭路磨矿流程作为一个整体来考虑的赤铁矿磨矿全流程运行反馈控制方法,实现球磨机给矿量、球磨机入口矿浆水矿比、螺旋分级机溢流浓度、旋流器给矿浓度四个基础回路的设定控制与设定值跟踪控制。该方法具有智能设定控制层和基础回路控制层两层结构,其中智能设定控制层建立了基于案例推理基础回路预设定模块、基于RBF人工神经网络的磨矿粒度软测模型、基于规则推理的磨矿粒度反馈调节器和球磨机负荷故障诊断与自愈控制器；基础回路控制层则设计了球磨机给矿环节增益自适应内模控制器、基于物料平衡模型的前馈控制与Fuzzy-PI串级控制相结合的分级机溢流浓度复合控制器。通过对基础回路的设定控制与设定值跟踪控制,从而保证磨矿粒度指标的实际值处于其目标值范围内,并使球磨机工作在最佳负荷工作点附近。2、针对二段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,使旋流器给矿压力频繁波动在工艺规定范围外的状况,提出了由泵池液位区间控制和旋流器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,保证再磨过程安全运行,提高旋流器分级效率。3、在上述智能运行反馈控制方法和再磨过程基础回路控制方法的基础上,设计了赤铁矿磨矿全流程智能控制系统。控制系统硬件包括皮带秤、流量计、液位计、压力传感器等检测仪表,电动调节阀、变频器等执行机构,以及PLC控制系统、监控计算机、计算机网络等。控制系统软件包括过程监控软件、磨矿全流程智能运行反馈控制软件和再磨过程控制软件,其中过程监控软件实现了球磨机给矿量、各处加水流量、矿浆浓度、给矿压力、泵池液位等工艺参数的监控以及生产设备的程序启停功能；智能运行反馈软件实现了磨矿粒度指标、球磨机负荷为目标的基础回路设定与跟踪控制；再磨过程控制软件实现泵池液位区间与旋流器给矿压力的模糊切换控制。4、将上述研制的赤铁矿磨矿全流程智能控制系统应用于酒钢选矿厂赤铁矿磨矿生产过程,实现了以磨矿粒度和球磨机负荷为目标的磨矿过程智能回路设定与跟踪控制,并将二段再磨泵池液位和旋流器给矿压力的波动控制在工艺规定的范围内。磨矿全流程智能控制系统的长期运行表明,磨矿粒度指标从72.96%提高到76.72%,提高了3.76个百分点,球磨机台时处理量提高了2.65%,磨矿产品单吨电耗降低2%以上,同时杜绝了球磨机“过负荷”和“欠负荷”故障工况的发生,取得了显著应用成效。磨矿全流程智能控制系统的成功应用,验证了本文所提方法的有效性和实用性。
[Abstract]:China is rich in hematite resources, but most are low grade hematite, complex mineral composition, iron ore is magnetized low coefficient of useful mineral qianbulidu uneven thickness, the characteristics of close symbiosis between minerals, a ball mill with spiral classifier is widely used, two milling machine and cyclone composed of two stage closed circuit grinding the process of drawing, the main task will be to the particle size of the grinding product index (often with -200 mesh% said,%200mesh) in the process control provisions within the range of the target value, the useful minerals and gangue monomer dissociation, the procedure provides qualified size for subsequent separation pulp industry; at the same time the ball mill load control in the optimal point, improve the mill capacity, to improve the grinding efficiency. Therefore, to achieve control of the whole process of grinding process to improve the flotation production targets, reduce all has the important practical significance because of my energy consumption. A rod mill in hematite ore grinding process is different from the foreign commonly used open grinding, two ball mill closed and hydrocyclone grinding process is a complex metallurgical process, mainly in: 1, hematite ore grinding process is composed of two sections of continuous closed circuit grinding composition that process is longer, more operational factors affecting the grinding particle size index, such as the volume of ore mill, ball mill entrance water, spiral classifier overflow concentration, cyclone feed concentration and other technological parameters, and hematite magnetic particles are "magnetic reunion" phenomenon, the online detecting instrument to size the true measure of grinding size index, so it is difficult to use conventional control method to realize the operation of the feedback control in the actual production process is widely used in manual control mode according to the grinding size test value Based on the set value control loop to adjust, but because of a manual test cycle is longer, not in real time on the grinding process guidance, resulting in a large size range of grinding, unable to choose don't process increasing the particle size of qualified pulp; 2, hematite ore properties makes frequent fluctuations in a grinding process is not the uncertainty caused by the ball mill load operating point drift, to make it work in the "low load" or "overload" fault conditions, the ball mill "Rose belly" or "empty hit" the accident is serious, the impact of safe and stable operation of the grinding process; 3, foreign commonly used quantitative feeding, ratio of rod mill the water supply and open circuit grinding provide ore granularity qualified for the grinding process, the slurry flow stability, the closed-loop constant control method can control the regrinding process pump pool level, and will not cause the cyclone Large fluctuations to the mine pressure; and a hematite ball mill with spiral classifier closed circuit grinding process of slurry flow fluctuation, and sump level by sewage, water flushing effect of random interference, resulting in re grinding process of the sump level frequent fluctuations, if the conventional closed-loop control mode is set value need to change large slurry pump speed, leading to the cyclone feeding pressure fluctuation, influence the classification efficiency of hydrocyclone, so the conventional closed-loop constant control method is difficult to be applied to hematite regrinding process. To sum up, the actual production of hematite in China must be combined with the grinding process, to adapt to the development of China's hematite ore grinding process the basic loop control method and the whole process of operation of the feedback control method, to improve the quality of grinding products, improve grinding efficiency, reduce energy consumption has important practical significance. This paper relies on the national key basic research and development program (973) "as the important project of complex manufacturing process integration control system overall control strategy and operation control method" (number: 2009CB320601), put forward the control strategy in the whole process of grinding the grinding granularity index and load control target of hematite, the Hematite the grinding process and grinding operation feedback control loop control method based on process, and on the basis of the design and development of intelligent control software of hematite ore grinding process, combined with the "transformation project of Jiuquan beneficiation plant integrated automation system, the hematite grinding process intelligent control system software and hardware. The structure design, installation, commissioning, and operation of the industrial experiment, the achievements are as follows: 1, according to the characteristics of production technology of hematite ore grinding process and has integrated complex characteristics, put forward The two section of continuous closed circuit grinding process as a whole to consider the whole process of hematite ore grinding operation feedback control method, realize the volume of ore mill, pulp mill entrance water ratio, spiral classifier overflow concentration, cyclone feed concentration of four basic loop set control tracking control and the method setting. With intelligent setting control loop control layer and the base layer two layer structure, the intelligent control setting establishes case based reasoning based loop pre setting module based on the particle size of RBF artificial neural network soft sensor model based on rule reasoning grind size feedback regulator and load fault diagnosis and self-healing controller based on the basic loop; the control layer is designed for ball mill feeding link gain adaptive internal model controller, feedforward control and Fuzzy-PI mass balance model for cascade control based on the combination of Machine level overflow concentration composite controller. Based on the basic loop set control tracking control with the set value, so as to ensure the grinding size index of the actual value in the target range, and make the mill work in the vicinity of the optimal load operating point of.2, because of the influence of the two stage grinding process of the sump level by random disturbance of cause, sump level fluctuations, the cyclone feed pressure fluctuation in the process outside the scope of the situation, put forward by the pump pool level interval control and cyclone feed pressure loop fuzzy control switch control method is composed of the sump level by controlling the interval to the mine pressure setting switch holder and fuzzy the compensator, feeding pressure setpoint control fluctuations in the allowable range; through the feeding pressure PI loop controller to track its set value, thus the sump level control in the target range And, to mine the fluctuation of pressure control in the allowed range, to ensure the safe operation of grinding process, improve the classification efficiency of hydrocyclone in the intelligent operation of.3, feedback control method and regrinding basic loop control method on the process of the design of the hematite grinding process intelligent control system hardware of the control system. Including belt scale, flow meter, level meter, pressure sensor and detection instrument, electric control valve, actuator and inverter, PLC control system, computer monitoring, computer network and so on. The control system software including process monitoring software, the whole process of the grinding operation intelligent feedback control software and regrinding process control software, including process monitoring software implementation of the volume of ore mill, all water flow, slurry concentration, feeding pressure, monitor the pump tank level and other parameters of the production equipment and the program start stop function; intelligent operation Fed software of grinding size index, set the basis for the target and the ball mill load loop tracking control; regrinding fuzzy switching control.4 process control software to realize the sump level interval and cyclone feeding pressure, the development of hematite ore grinding process intelligent control system used in Jiuquan beneficiation plant hematite grinding process, the grinding and tracking control of intelligent circuit to process ore grinding size and load as the goal, and the two section grinding pump pool level and cyclone feed pressure fluctuation is controlled in the range of technology within the prescribed that the long term operation of grinding process intelligent control system. The grinding granularity index increased from 72.96% to 76.72%, an increase of 3.76 percentage points, the ball milling increases 2.65%, grinding products to reduce power consumption more than 2% tons, and eliminate the "overload" and the ball mill The application of "under load" fault condition has achieved remarkable results. The successful application of the intelligent control system of grinding process proves the effectiveness and practicability of the proposed method.

【学位授予单位】：东北大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD951;TD67
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本文编号：1716405