JP2001300204A - Temperature control method in batchwise crystallization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously control the temperature of the content in the container of a batchwise crystallization apparatus employing a cooling method. SOLUTION: An automatic control unit 40 equipped with a memory means, a measured value obtaining means and a control means is arranged to the batchwise crystallization apparatus 50. The memory means stores a temperature target value, a set water supply amount and a set standby time. The measured value obtaining means obtains a measured value from a thermometer 20. The control means compares the measured value with a target value at each point of time when the set standby time is elapsed and issues a command to a cooling water supply means 30 so as to supply cooling water to a jacket 22 by the set water supply amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling temperature in a batch type crystallizer, and more particularly, to a method for continuously controlling the temperature of contents in a container in a batch type crystallizer by a cooling method.

[0002]

2. Description of the Related Art In a crystallization operation by a cooling method using a batch type crystallization apparatus, temperature control of the contents in a vessel for crystallization is a very important factor. In this case, assuming that the solution saturation concentration curve and the permissible maximum supersaturation concentration curve are known, the temperature of the contents in the container is determined as the operation oversaturation with respect to the change in the solution concentration with respect to the elapsed time of the crystallization operation, i.e. The temperature is controlled according to the operating solution temperature change curve to maintain the temperature. The control method is a method of controlling the operation solution temperature change curve by programming. For this type of continuous control, a program control using an on-off control as a basic control system is used.

FIG. 5 is a schematic view showing an example of a conventional batch crystallization apparatus using a cooling method. The present crystallization apparatus 10 obtains a crystal B from a solution A by a crystallization operation. The crystallization apparatus 10 includes a container 12 that accommodates the solution A and proceeds with crystallization to obtain crystals. The container 12 is a sealed vertical container, and has an inlet 14 for feeding the solution at its head,
A product port 16 for taking out crystals is provided at the bottom, and a stirrer 18 is provided inside.

In order to control the temperature of the contents in the container 12 in accordance with the operating solution temperature change curve, the crystallizer 10 includes a thermometer 20 for measuring the temperature of the contents in the container 12, which is cooled in the container 12. A jacket 22 for flowing water to cool the contents in the container 12 is provided on the outer periphery of the container 12, and a thermometer 2 is provided.
While monitoring 0, the contents in the container 12 are cooled by the cooling water. The jacket 22 is provided with cooling water.
A water supply port 26 connected to a cooling water supply pipe 24 is provided at the bottom, and a cooling water overflow discharge port 28 is provided at the upper part. The supplied cooling water replaces the heated cooling water in the jacket 22. It is extruded from the outlet 28 in the form. The cooling water supply pipe 24 is provided with a cooling water valve 31, and the cooling water supply pipe 30 and the cooling water valve 31 constitute a cooling water supply unit 30.

In the crystallization apparatus 10, the temperature of the contents in the container 12 is measured by a thermometer 20, and a cooling water valve 31 is opened and closed according to the level of the temperature of the contents, thereby supplying cooling water. The temperature of the contents is controlled by on / off control of stopping and controlling the temperature of the contents.

[0006]

However, the above-mentioned on / off control used for temperature control in a batch type crystallizer has a limited temperature controllability and a large temperature control range. There is a problem that it is difficult to control the temperature with a temperature gradient according to the operating solution temperature change curve, and it is difficult to obtain a high quality product in a high yield.

The present invention has been made in view of the above-mentioned circumstances, and is a method for controlling the temperature of the contents in a vessel in a batch crystallization apparatus. It is an object of the present invention to provide a method capable of controlling the temperature of the contents in a container while controlling the temperature continuously with better controllability than on-off control.

[0008]

According to the present invention, there is provided a container for precipitating a crystal from a solution therein.
A jacket provided on the outer periphery of the container, for cooling the contents in the container by flowing cooling water, cooling water supply means for supplying cooling water to the jacket, and a thermometer for measuring the temperature of the contents in the container. A method for controlling the temperature of the contents in a container in a batch type crystallizer provided with a target value of the temperature of the contents in the container set in advance so as to fluctuate with time, and the temperature of the contents in the container The set water supply amount to the jacket specified as the amount by which the water supply is changed and the set standby time specified as the delay time until the temperature change occurs in the contents in the container after supplying the cooling water at the set water supply amount to the jacket are stored. Storage means, a measurement value obtaining means for obtaining a measured value of the temperature of the contents in the container from the thermometer, and a container in the container obtained by the measurement value obtaining means for each time the set standby time read from the storage means has elapsed. Contents of The measured temperature value is compared with the target value of the temperature of the contents in the container read from the storage means, and when the measured value deviates from the target value, the set water supply amount to the jacket is read from the storage means. A control means for issuing a command to the cooling water supply means so as to supply the cooling water to the jacket by the set water supply amount, and operating the cooling water supply means by the automatic control apparatus to control the contents in the container. A temperature control method for a batch crystallization apparatus, wherein a temperature of a product is controlled to a target value.

The storage means, measured value acquisition means and control means used in the present invention can be realized by using a known computer.

In the present invention, when determining whether the measured value deviates from the target value, a deviation amount is set, and the measured value of the temperature of the contents in the container deviates from the target value by more than the deviation amount. In such a case, it may be determined that there is a deviation.

Further, at least one of the set water supply amount and the set standby time may be set in accordance with a correlation with a magnitude of a deviation between the target temperature value and the measured value.

As is apparent from the above configuration, in the present invention, the measured value acquiring means acquires the measured value of the temperature of the contents in the container from the thermometer of the crystallizer, and the target value read from the storage means. Compare. When the measured value deviates from the target value, the set water supply amount is read from the storage means, and a command is issued to the cooling water supply means provided in the crystallizer to supply the cooling water to the jacket by the set water supply amount. . The set standby time is read from the storage means, and the above operation is repeated every time the set standby time elapses. Thereby, the present invention operates the cooling water supply means of the crystallizer by the automatic control device, and continuously and without a time delay, based on the set value, that is, according to a clear operation standard, the temperature of the contents in the container. Can be controlled to the target value.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The present embodiment is an example in which the temperature control method according to the present invention is applied to the above-mentioned batch crystallization apparatus shown in FIG. FIG. 1 is a schematic diagram of a crystallization apparatus of the present embodiment, FIG. 2 is a schematic diagram showing a hardware configuration of an automatic control device, and FIG. 3 is a configuration of a control program operated by a computer provided in the automatic control device. FIG. 4 is a flowchart showing the flow of the control program.

The batch type crystallizer 50 of this embodiment includes:
An automatic control device 40 is provided. As shown in FIG. 1, the automatic control device 40 cooperates with a thermometer 20 and a flow rate control valve 32 provided on a cooling water supply pipe 24 to operate the contents (solution or solution) in the container 12. And a mixture of crystals). That is, in the present example, the cooling water supply means 30 is provided by the cooling water supply pipe 24 and the flow control valve 32.
Is configured. Since the other configuration of the apparatus in FIG. 1 is the same as that of the apparatus in FIG. 5, the same reference numerals in FIG. 1 denote the same parts as in FIG. 5, and a description thereof will be omitted.

As shown in FIG. 2, the hardware configuration of the automatic control device 40 is as follows: a control computer 42, which is a computer having a known configuration and is provided for operating a control program; a thermometer 20; An input / output module 44 provided as an input / output interface for transmitting and receiving signals between the valve 32 and the control computer 42; a target value of the temperature of the contents in the container 12; a set water supply amount to the jacket; , A keyboard 46 for inputting data such as set standby time, and a CRT monitor 48 for displaying input / output data and the like.
It is located on an operator console (not shown).

The main part of the control program operated by the control computer is, as shown in FIG. 3, the types of crystal products manufactured in the container 12 (in FIG. 3, simply a, b, c
, A database 52 storing data set for each crystal type, acquiring and storing necessary data from the database 52, and measuring values inputted from the thermometer 20. And a control program 56 that reads data from the data buffer 54 and operates based on the data.

The setting data stored in the database 52 is roughly classified into operation data and control tuning parameters. The operation data is a target value of the temperature of the contents in the container 12, and the control tuning parameters are the set valve opening of the flow control valve 32, the opening period of the flow control valve 32, and the standby time (that is, the flow control valve 32). Closing period).

In this embodiment, the operation performed by the cooling water supply means 30 in accordance with an instruction from the automatic control device 40 includes a flow control valve 32
This is an operation of opening the cooling water and introducing the cooling water into the jacket 22, and the supply of the cooling water of the set water supply amount is realized by the set valve opening and the set open period.

The target value stored in the database 52, the set valve opening degree and the set open period of the flow control valve 32, and the set standby time (that is, the closed period of the flow control valve 32) are input via the keyboard 46. The measured temperature value is input from the thermometer 20 via the input / output module 44, and is temporarily stored in the data buffer 54.

In this embodiment, the target value of the temperature of the contents in the container is set in advance so as to fluctuate with time. Specifically, it is set in accordance with the operating solution temperature change curve. This target value is set according to the type of the solution A, the type of the crystal B, and the like.

The control program 56 proceeds according to, for example, a flowchart shown in FIG. As soon as the temperature control is started, the process proceeds to step S1. In step S1, a target value and a measured value of the temperature of the contents in the container 12 are received from the data buffer 54, and the measured value is compared with the target value to determine whether the measured value is higher than the target value. When the measured value is higher than the target value, the process proceeds to step S2, and when the measured value is equal to or lower than the target value, the process proceeds to step S1 '. Step S1 '
In the waiting step, after waiting for a predetermined time, the process returns to step S1 again. The predetermined time may be the same length of time as the set standby time. In step S2, the flow control valve 32
Is read from the data buffer 54, a command is issued to the flow control valve 32, the flow control valve 32 is opened at the set valve opening, and the process proceeds to step S3 after the set open period has elapsed. . In step S3, the flow control valve 32 is closed, and the process proceeds to step S4. Step S
Reference numeral 4 denotes a standby step, in which the set standby time is read from the data buffer 54, and after the elapse of the standby time, the process returns to step S1 again. Hereinafter, the above-described routine is repeated to control the temperature of the contents in the container 12.

In the temperature control according to the above routine, the cooling water is introduced into the jacket 22 at a flow rate corresponding to the set valve opening during the set opening period of the flow control valve 32 in step S2, and the inside of the jacket 22 is heated. The same amount of cooling water is discharged from the overflow discharge port 28 so as to be pushed out. Thereby, the temperature of the cooling water in the jacket 22 decreases, and the content in the container 12 can be cooled to lower the temperature.

As described above, in the present embodiment, when the heated cooling water in the jacket 22 is replaced with the low-temperature cooling water and the temperature of the contents in the container 12 is lowered with the low-temperature cooling water. As a control tuning parameter, the set water supply amount is set according to the valve opening degree and the opening time of the flow control valve 32 for each product type in accordance with the difference in the operating solution temperature change curve for each product. The standby time at which a temperature change occurs is set for each product type. Further, a target value of the temperature of the contents in the container is set as operation data for each product type. Then, when the measured value exceeds the target value, the temperature control routine of supplying the cooling water to the jacket by the set water supply amount and then waiting for the standby time is repeated.

Thus, the temperature of the contents in the container 12 is automatically and continuously controlled based on the target temperature, the set water supply amount, and the set standby time, that is, based on a clear operation standard. Therefore, the product quality is stable and the yield is improved. Further, since the waiting time, that is, the waiting time is set and managed based on the actual data, the controllability and productivity of the crystallizer are improved.

In the above-described embodiment, the cooling water supply means 30 is constituted by the cooling water supply pipe 24 and the flow control valve 32. However, the construction of the cooling water supply means 30 is not limited to this. Any configuration can be adopted.

[0026]

According to the present invention, the target value of the temperature of the contents in the batch type crystallizer is compared with the measured value, and when the measured value deviates from the target value, the cooling water supply means is provided. The cooling water is supplied to the jacket by the set water supply amount, and after the set standby time elapses, the same routine is performed again, so that the content in the crystallizer is automatically and continuously based on the set clear criteria. Since the temperature of the product can be controlled, the quality of the product is stable and no variation occurs, and the yield is improved.
Further, since the standby time, that is, the control standby time is set and managed based on the data, the controllability and productivity of the crystallizer are improved. Furthermore, by regulating the standby time and operating the cooling water supply means, the temperature of the contents in the crystallizer can be stably controlled within a short time. Further, since the delay time until the response to the operation appears is compensated by the standby time, the operation amount is not excessively increased, so that an adverse effect is not given to the crystallization operation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a first embodiment in which a temperature control method according to the present invention is applied to a batch crystallization apparatus.

FIG. 2 is a schematic diagram illustrating a hardware configuration of the automatic control device according to the first embodiment.

FIG. 3 is a block diagram illustrating a configuration of a control program operated by a computer provided in the automatic control device according to the first embodiment.

FIG. 4 is a flowchart of a control program.

FIG. 5 is a schematic diagram showing a configuration of a batch type crystallizer having a conventional temperature control system.

[Explanation of symbols]

 10 batch type crystallizer 12 container 20 thermometer 22 jacket 24 cooling water supply pipe 30 cooling water supply means 31 cooling water valve 32 flow control valve 40 automatic control device 50 batch type crystallizer

Continuation of the front page F term (reference) 5H323 AA01 BB02 CA04 CB23 CB33 DA04 DB15 EE05 FF01 GG02 HH02 KK01 KK05 LL05 LL19 MM06 NN03

Claims (1)

[Claims] 1. A container for depositing crystals from a solution therein, a jacket provided on an outer periphery of the container, for flowing cooling water to cool contents in the container, and cooling water supply means for supplying cooling water to the jacket. And a method of controlling the temperature of the contents in the container in a batch crystallization apparatus equipped with a thermometer for measuring the temperature of the contents in the container, wherein the inside of the container is set to fluctuate with time in advance. The target value of the temperature of the contents, the set water supply amount to the jacket specified as the amount that changes the temperature of the contents in the container, and the temperature of the contents in the container after supplying the cooling water with the set water supply amount to the jacket Storage means for storing a set standby time defined as a delay time until a change occurs; measured value obtaining means for obtaining a measured value of the temperature of contents in a container from a thermometer; and set standby time read from the storage means Has passed At each point in time, the measured value of the temperature of the contents in the container obtained by the measured value obtaining means is compared with the target value of the temperature of the contents in the container read from the storage means, and the measured value is compared with the target value. When there is a deviation, an automatic control device including a control unit that reads a set water supply amount to the jacket from the storage unit and issues a command to the cooling water supply unit to supply the cooling water to the jacket by the set water supply amount is used. A temperature control method for a batch crystallization apparatus, wherein the temperature of the contents in the container is controlled to a target value by operating the cooling water supply means by the automatic controller.