JPH063445Y2 - PH control device for batch waste liquid treatment process - Google Patents

Description

Description of the invention] of waste the present invention <BACKGROUND OF THE> is to be batch to emissions from a chemical factory P _H
To neutralize the values for improved control of P _H control batch waste treatment process for discharged to rivers.

<Prior Art> A general configuration of a batch waste liquid treatment process will be described with reference to FIG. Reference numeral 1 denotes a waste liquid tank for temporarily storing the waste liquid F from the process, and the waste liquid in the tank is neutralized by a neutralization tank 4 via an opening / closing valve 2 controlled by a batch start signal B and an input pipe line 3.
Be led to.

Acid solution tank for neutralization 5, 6 is the same alkali solution tank for neutralization, a solution of each tank, the waste liquid F P _H
One is selected based on the value and is supplied to the neutralization tank 4 via the flow rate control valves 7 and 8 and the common neutralization pipe line 9, respectively.

10 is a sensor of _{P H} in the neutralization tank in solution F ', the measured value PV ₁ is guided to the controller 11.

The controller 11 starts at the start batch signals B, the measurement value PV ₁ and _{P H} 7 was controlled calculates the deviation of the set value SV ₁ corresponding to the operation output MV _H or MV _N control valve 7 or 8
Supply to.

In this case, to supply neutralizing solution from the acid solution tank 5 when P _H value is 7 or more alkaline by transmitting an operation output MV _H solution F 'by the measurement value of P _H, P _H value is 7 or less When it is acidic, MV _N is emitted and the alkaline solution tank 6
Supply more neutralizing solution.

The solution F ′ in the neutralization tank 4 is supplied to the output pipe line 12, the pump 13,
River 16 via on-off valve 14 and waste pipe 15.
Is discharged to.

17 is a level sensor of the neutralization tank, PV ₂ is the measured value. 18 is a level monitoring controller that starts with the batch signal B, and the measured value PV ₂ is the discharge level set value SV.
_When it reaches ₂ , the operation signal MV ₂ for opening the on-off valve 14 is transmitted.

Process effluent F <Problems to be Solved invented> the type of product and that have been manufactured, shows a significantly different P _H values for each batch by the operating state of the plant. Conventionally, a nonlinear P, I, D controller is often used as the controller 11, and P,
I, since D parameter is previously preset value, it may significantly inappropriate when viewed from the P _H value of the waste.

As a means to eliminate such inconvenience, a self-tuning controller that automatically tunes optimum P, I, and D parameters each time the batch is started is beginning to be used, but the initial values of the P, I, and D parameters are If it is not appropriate, there is a drawback that the convergence time of tuning becomes long or untunable, resulting in large hunting.

The present invention is Ruru able to solve such problems P _H
It is intended to provide a control device.

The features on the configuration of the present invention <Means for solving the problems> acid to neutralize based on P _H measurements of process waste liquid savings neutralization tank is discharged batchwise or an alkaline solution has a control means for supplying to the neutralization tank, determine neutralized intracisternal solution in P _H control apparatus of a batch waste water treatment process that leads to rivers, as a supply control means, at the time of the previous batch If the deviation of the control result is equal to or less than a certain value, the control parameter is set as a new control parameter, and if the deviation is equal to or more than the certain value, the control is performed a plurality of times in the past. The point is that a self-tuning cotton roller is provided for estimating and setting optimum control parameters from the control parameters determined at the time of batch.

<Operation> According to the present invention, the self-tuning controller is used as the control means, and the initial value of the control parameter at the start of tuning in the next batch is the actual value of the optimum parameter value determined in the past multiple batches. Based on the learning calculation function.

<Embodiment> The hardware configuration is the same as the configuration shown in FIG. 1 described in the prior art, and therefore the description of each element is omitted.

"The feature of the present invention is that a self-tuning controller having an optimum parameter determination procedure described below is installed as the controller 11." The procedure will be described with reference to the flowchart of FIG.

(1) First, when the waste liquid is supplied to the neutralization tank at the start of batch,
In step, the controller executes control for a certain period of time with the preset P, I, and D parameters determined at the previous batch as initial values.

(2) The deviation of the control result is judged in step, and if the deviation is larger than a certain value, it is considered that the control is bad, and the process proceeds to step.

In step (3), self-tuning for adaptive control is executed, and new P, I, D parameters are calculated.

(4) The new P, I, D parameters are used to control the step for a certain period of time, and the deviation due to the step is checked again. If the deviation is less than a certain value, the control is considered to be good, and the process proceeds to the step.

In step (5), preset P, I, D parameters or new P, I, D parameters calculated in step are stored in memory, and P, I, D in this batch control are stored.
And executes the P _H control adopted as D parameter, the flow proceeds to step.

The step (6) is a learning calculation function which is a feature of the present invention, and is based on the optimum P, I and D parameter values determined and used in the past K times of batch control and at the start of the next batch control. Estimate preset P, I, D parameter values.

FIG. 3 is an explanatory diagram showing an example of the estimation calculation. When the present tuning parameter value is Pn and the tuning parameter values of the past five times are Pn- _{1 to} Pn _{- 5} , respectively,
The next preset parameter value Pn _{+ 1} is estimated as the moving average value of the present and past five times.

In step (7), preset P, I, and D parameter values estimated and determined in step are stored as initial values, and a standby state is set for the next batch control.

The mode of the learning calculation in the step is generally the moving average calculation described above, but may be a calculation by an algorithm that introduces other parameters.
It is also possible to empirically construct an algorithm with high estimation accuracy of I and D parameters.

As the self-tuning controller used in the present invention, various known methods such as the limit sensitivity method, the indial response method, and the expert method can be used.

As described <devised Effects>, appropriate preset P from the start of the batch control according to the present invention, I, can be easily realized tuning possible control device by the D parameter, the P _H It is possible to significantly reduce the hunting of the waste liquid treatment process, which is subject to severe fluctuations, and improve its controllability.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a flow chart diagram for explaining the operation procedure thereof, and FIG. 3 is an operation explanatory diagram of a learning calculation function. 1 ... Waste liquid tank, 2, 14, ... Open / close valve, 3 ... Input conduit, 4 ...
Neutralization tank, 5 ... Acid solution tank, 6 ... Alkaline solution tank,
7,8 ... control valve, 9 ... neutralization line, 10 ... _{P H} sensor,
11 ... Self-tuning controller, 12 ... Output pipeline, 13 ... Pump, 15 ... Waste fluid pipeline, 16 ... River, 17
… Level sensor, 18… Level monitoring controller

Claims (1)

[Scope of utility model registration request] 1. A control means for supplying an acid or alkali solution to the neutralization tank to neutralize based on P _H measurements of process waste liquid savings neutralization tank is batchwise discharge a, performed in P _H control apparatus of a batch waste water treatment process that leads neutralized intracisternal solution rivers, as the control means, the predetermined time control the control parameters that are determined during the previous batch as the initial value However, if the deviation of the control result is a certain value or less, the control parameter is a new control parameter, and if the deviation is a certain value or more, the control parameter that is more optimal than the control parameter determined in the past multiple batches. the P _H control batch waste water treatment process, characterized in that a self-tuning controller for setting estimated calculation.