The Research Of The PH Predictive Control System In The Sewage Water Treatment

The non-linear and lagging usually appears seriously in the neutralization course of acid and alkali, it not only brings a great difficulties for PH value control, but also wastes a large amount of neutralizer, so PH value is recognized as one of the most difficult control variables. In recent years, people are trying to use some new control method to solve this difficult problem constantly. So there are very important theory meanings and applied value in the research of the problem of PH value controlling.At first, this paper introduce the development status of sewage disposal and automatic control technology home and overseas, and mention the lower automatic level of PH controls and problems faced in the sewage disposal of our country emphatically.Secondly, according to the request of acid wastewater treatment craft, a set of software and hardware solutions for one acid wastewater process systems of high performance based on software kingview 6.5 and Omron PLC has been proposed and realized. The Hardware includes the hardware design of the master and the slave machine, the design and choice of the electric control system, and also the design and installation of the switch board and the control board. The software includes the description of the software function for the master and the salve machine and the software writing.On the basis of theory analyse for PH control process, aim at the difficult problem that the PH have serious nonlinearity and lagging in the neutralization, this paper has used one kind of step optimized predictive control algorithms for non-linear system, namely using the thought that the steps algorithm solves the non-linear optimum in the theory of the great system, non-linear optimization is turned into two grades calculation that linear optimization and harmony through the steps algorithm, it has avoided the difficulty of solving non-linear optimization directly, has reduced its calculation amount, make the predictive control algorithm can meet the demand of real-time control. In addition, the author gives a stimulation to the advanced predictive control algorithm by the simulink of the MATLAB, to optimizes parameter and improve the stability and the precision. The result is satisfactory. Also a good try has been made in practice by the advanced predictive control algorithm.The control system of waste acid water is operated simply with the characteristic of high adjustability, high reliability, and high stability. The operation state is reliable and steady since it is put into operation and the control precision is improved to insure the sewage emission for up to par, avoid polluting the Gan River by superscale of sewage emission for wrong operation, out of control.The production of the paper follows: the key technical problem is settled successfully in the process of waste acid water treatment, giving a new paper in the automatically control system of rolling mill dealing with waste acid water in our province and the economic benefit is salience. The mature technology and the reliability running experience of the device can give successful experience for sewage water treatment in other field.Finally, the summary is made, analysis of existing problem to the work is given, and the author looks forward to the developing direction in the future.