JP2012164206A - Temperature control system and temperature control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature control system capable of stabilizing the temperature of target fluid at a predetermined setting temperature SV in an early stage with simple means.SOLUTION: A temperature control device 9 adjusts the temperature of hot water W to a predetermined setting temperature SV. The temperature control device 9 includes: a cooling device 13 for adjusting the temperature of the hot water W; a PID control unit 21 for exerting PID control to the cooling device 13 to adjust the temperature of the hot water W; a detection unit 22 for detecting a deviation of a measured temperature PV according to the setting temperature SV of the hot water W; a determination unit 23 for determining whether the sign of the deviation detected by the detection unit 22 reverses; and a sudden change control unit 24 for, when the determination unit 23 determines that the sign of the deviation reverses, stopping PID control by the PID control unit 21 and exerting sudden change control in which the degree of valve opening of a flow control valve 14 of the cooling device 13 is changed suddenly by the predetermined degree of opening α.

Description

  The present invention relates to a temperature control system and a temperature control method applicable to various processes, and in particular, in a manufacturing process in a chemical plant or the like, a temperature control system that accurately and stably controls a temperature in a target system by a heating unit or a cooling unit. And a temperature control method.

  In general, in temperature control of a reaction vessel or the like using a feedback control instrument, it may take 10 minutes or more until the temperature in the reaction vessel is stabilized in response after the jacket temperature changes. This is peculiar to PID control. During the PID control, a temperature control valve that adjusts the temperature when the deviation of the measured temperature PV is reversed with respect to the set temperature SV (for example, T1 in FIG. 5A). This is because the operation gradually proceeds in the reverse direction (see FIG. 5B). That is, at the time when the deviation between the set temperature SV and the measured temperature PV is reversed, the valve opening degree of the temperature regulating valve that is temperature-controlled tends to be too open or closed, and the tendency further increases when the deviation increases. growing.

  Especially when the temperature of the reactor is adjusted by PID control, due to space problems, etc., when the external heat (or cooling) fluid supply position for adjusting the jacket temperature is installed at a position far from the jacket Is a relatively large time delay from the change in the amount of heat (or cooling) fluid to the change in jacket temperature. In addition, this delay causes a further delay in the temperature change of the reaction tank. As a result, the temperature of the reaction tank becomes unstable and hunting occurs.

  In this way, in the temperature adjustment of the jacket by the feedback control instrument in the normal PID calculation method, if the same calculation method is employed, the temperature disturbance of the reaction vessel often increases, and in some cases, overshoot may occur. was there. Thus, many improved methods for improving the control method have been proposed for such a temperature control method. For example, Patent Document 1 discloses a method of adopting each PID control method for each temperature control in a step thermo-type temperature control in which a plurality of reference set temperatures and their upper limit values and lower limit values are set. Document 2 discloses a method of switching the controller when one deviation with respect to the set temperature is reached, Patent Document 3 discloses a method of employing fuzzy control, and Patent Document 4 discloses integration in PID control. A method comprising an integral upper limit value predicting means for predicting an upper limit value is disclosed.

JP 2003-316448 A JP 2004-246773 A JP-A-6-51846 JP-A-4-118709

  However, in the control method described above, although the magnitude of the output signal by PID control is different, the basic output operation as PID control is the same. That is, when the deviation of the measured temperature PV with respect to the set temperature SV is reversed, the temperature regulating valve that is adjusting the temperature gradually operates in the reverse direction, and the deviation between the set temperature SV and the measured temperature PV is the same. At the time of reverse rotation, the valve opening degree of the temperature control valve that is adjusting the temperature tends to be too open or closed, and obviously the valve operation as the temperature control is delayed.

  Further, in the method described in the above-mentioned patent document, since the system itself is complicated, the load on the computer becomes high and the device becomes expensive. In addition, by adjusting one side, there are many cases in which it is necessary to perform tuning in conjunction with the other, and there is a problem that more time and labor are required to cope with this.

  An object of the present invention is to provide a temperature control system and a temperature control method capable of quickly stabilizing the temperature of a target fluid at a predetermined set temperature SV by simple means.

  In order to solve the above problems, a temperature control system according to the present invention is a temperature control system for adjusting the temperature of a target fluid to a predetermined set temperature SV, and includes a cooling device for adjusting the temperature of the target fluid, and At least one of the temperature raising device, first control means for executing feedback automatic control on at least one of the cooling device and the temperature raising device to adjust the temperature of the target fluid, and the target fluid with respect to the set temperature SV of the target fluid Detecting means for detecting the deviation of the measured temperature PV, determining means for determining whether the positive / negative of the deviation detected by the detecting means is inverted, and when the positive / negative of the deviation is determined to be inverted by the determining means The automatic feedback control by the first control means is stopped, and the opening degree of the temperature control valve of at least one of the cooling device and the temperature raising device is set to a predetermined opening amount. Only it comprises a second control means for executing a rapid change control for rapid change, the.

  The temperature control method according to the present invention adjusts the temperature of the target fluid to a predetermined set temperature SV in a temperature control system including at least one of a cooling device and a temperature raising device for adjusting the temperature of the target fluid. A temperature control method for controlling a target fluid with respect to a set temperature SV, a first control step for performing feedback automatic control on at least one of a cooling device and a temperature raising device to adjust the temperature of the target fluid When it is determined that the detection step for detecting the deviation of the measured temperature PV of the fluid, the determination step for determining whether the positive / negative of the deviation detected in the detection step is reversed, and the positive / negative of the deviation is reversed in the determination step In addition, the automatic feedback control in the first control step is stopped, and the temperature control valve of at least one of the cooling device and the temperature raising device is And it includes a second control step of executing a sudden change control for changing the degree sharply predetermined opening degree amount, a.

  In the temperature control system and the temperature control method according to the present invention, when it is determined that the deviation of the deviation of the measured temperature PV from the set temperature SV of the target fluid is reversed, the automatic feedback control is stopped, and the cooling device and the temperature increase A sudden change control is executed in which the valve opening degree of at least one of the temperature control valves of the apparatus is changed abruptly by a predetermined opening degree. In this case, since the valve opening degree of the temperature control valve is changed abruptly by a predetermined opening degree, it is too open or closed when the positive / negative deviation of the measured temperature PV with respect to the set temperature SV is reversed. The valve opening degree of the temperature control valve having a tendency can be corrected to an appropriate opening degree at an early stage. As a result, the temperature of the target fluid can be quickly stabilized at the predetermined set temperature SV by simple means such as sudden change control.

  Further, in the temperature control system according to the present invention, the second control means controls the valve of the temperature control valve when it is determined by the reversal determination of the deviation that the measured temperature PV is lower than the set temperature SV. A temperature raising operation is performed to increase the temperature of the target fluid by changing the opening to a valve opening that is smaller by a predetermined opening, and the measured temperature PV is lower than the set temperature SV by the reversal determination of the positive or negative deviation. When it is determined that the temperature has increased, the temperature control valve is changed so that the valve opening degree is increased by a predetermined opening degree, and a temperature lowering operation is performed to lower the temperature of the target fluid. It is preferable. In this case, it is possible to reliably execute the stabilization of the temperature of the target fluid at the predetermined set temperature SV at an early stage.

  In the temperature control system according to the present invention, the predetermined opening degree is an opening width corresponding to at least 5% when the fully closed state of the temperature control valve is 0% and the fully open state is 100%. And the second control means executes sudden change control in which the opening degree of the temperature control valve is suddenly changed by a predetermined opening degree within one second after the judgment means judges that the sign of the deviation is reversed. It is preferable. In particular, it is more preferable that the predetermined opening degree at the time of sudden change control is an opening width between 5% and 40%.

  In the temperature control system according to the present invention, it is preferable that the second control unit cancels the stop of the automatic feedback control by the first control unit after executing the sudden change control. In this case, feedback automatic control is performed again after the valve opening degree of the temperature control valve that tends to be too open or closed when the positive / negative deviation of the measured temperature PV with respect to the set temperature SV is reversed is corrected. Therefore, the temperature of the target fluid can be stabilized to the predetermined set temperature SV even earlier.

  According to the temperature control system and the temperature control method according to the present invention, the temperature of the target fluid can be quickly stabilized at the predetermined set temperature SV by simple means.

It is the figure which showed typically the structure of the chemical plant containing a temperature control apparatus. It is a block diagram of the temperature control apparatus in this embodiment. It is a flowchart which shows the temperature control method in this embodiment. It is a figure which shows the relationship between the deviation and valve opening in this embodiment. It is a figure which shows the relationship between the deviation and valve opening in the past.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  First, with reference to FIG. 1, the whole structure of the chemical plant 1 containing the temperature control apparatus 9 which concerns on this invention is demonstrated. The chemical plant 1 includes a reactor 2, a jacket 3, a hot water tank 4, a pump 5, a pipe 6 for circulating hot water, a reactor temperature output unit (TIC-2) 7, a thermometer 8, a temperature control device (TIC-1) 9, The thermometer 10, the temperature raising device 11, the flow rate control valve 12 (temperature control valve), the cooling device 13, and the flow rate control valve 14 (temperature control valve) are configured. In the chemical plant 1, as will be described later, the temperature in the reactor 2 can be adjusted to a predetermined value by cooling the reactor 2 with circulating hot water W (target fluid).

  The reactor 2 is a vessel type reaction vessel with a stirrer, and is a reaction vessel for producing a polymer material (polymer) by a polymerization reaction, for example. The jacket 3 is a temperature adjustment member used to remove heat generated by various chemical reactions in the reactor 2, and is attached to the wall surface so as to cover at least a part of the outer periphery of the reactor 2. The jacket 3 is configured so that warm water W (for example, 70 ° C.) for cooling flows into the jacket 3, and acts to stabilize the temperature of the polymerization reaction in the reactor 2 (for example, 80 ° C.).

  The hot water tank 4 is a tank for accumulating hot water returned from the jacket 3 by the pipe 6 a and steam supplied from the flow rate adjusting valve 12 of the temperature raising device 11 as hot water W. Steam that is formed by heating water in advance is supplied to the hot water tank 4 from the temperature raising device 11, and the hot water W stored in the hot water tank 4 is the hot water temperature (for example, 70 ° C.) at the inlet of the jacket 3. The temperature is adjusted to be higher (for example, 80 ° C.). The flow rate adjustment valve 12 of the temperature raising device 11 is controlled so that the valve opening degree becomes constant after the hot water W in the hot water tank 4 is stabilized at a predetermined temperature (for example, 80 ° C.). The hot water tank 4 is configured to overflow when the accumulated hot water W becomes larger than a predetermined amount.

  The hot water W adjusted to a predetermined temperature in the hot water tank 4 is supplied from the lower end of the hot water tank 4 to the jacket 3 via the pipe 6b by the pump 5. The pipe 6b for supplying the hot water W from the hot water tank 4 to the jacket 3 is connected to the flow rate adjusting valve 14 of the cooling device 13 in the middle thereof, so that the cooling water from the cooling device 13 is supplied. ing. By supplying the cooling water to the hot water W supplied from the hot water tank 4, the hot water W is adjusted to the hot water W at a predetermined temperature (for example, 70 ° C.), and the temperature-adjusted hot water W is supplied to the jacket 3. Thereby, the temperature in the reactor 2 is adjusted to a predetermined value. Note that the hot water temperature is not adjusted in the hot water tank 4 by supplying the cooling water. If the temperature is adjusted in the hot water tank 4, it takes time to reach the target temperature, and the temperature of the reactor 2 is controlled. This is because there will be a delay in time.

  The flow rate adjustment valve 14 responsible for temperature adjustment as described above is controlled by the temperature control device 9. The temperature control device 9 is composed of a general PID control device (temperature controller), and receives information input of the measured temperature PV from the thermometer 10 that measures the temperature of the hot water W supplied to the jacket 3. Configured to be able to. When the temperature control device 9 receives the information of the measured temperature PV, the temperature control device 9 performs so-called PID control so that the measured temperature PV approaches the preset temperature SV set in advance, thereby controlling the valve of the flow rate adjustment valve 14 of the cooling device 13. Control the opening. The flow rate adjustment valve 14 of the cooling device 13 is controlled by a control signal from the temperature control device 9 so that the valve opening degree is a predetermined opening degree (for example, from the fully closed state (0%) to the fully open state (100%)). 40%).

  The reactor temperature output unit 7 can receive temperature information from a thermometer 8 that measures the temperature in the reactor 2, and outputs the received temperature information to the temperature control device 9. The temperature control device 9 changes the set temperature SV of the hot water W supplied to the jacket 3 according to the temperature in the reactor 2. In the following description, in order to make the control by the temperature control device 9 easy to understand, the set temperature SV of the hot water W is described as being constant, but even when the set temperature SV is changed according to the temperature in the reactor 2. Similar controls can be applied.

  The temperature control device 9 is a device that basically adjusts the temperature of the hot water W by controlling the valve opening degree of the flow control valve 14 by PID control, and stops the PID control only when a specific condition is met. It is an apparatus for executing the control method. As shown in FIG. 2, such a temperature control device 9 includes a PID control unit 21 (first control unit), a detection unit 22 (detection unit), a determination unit 23 (determination unit), and a sudden change control unit 24 (first change unit). 2 control means) and a storage unit 25.

  The PID control unit 21 is a part that performs PID control, which is one of automatic feedback control, for the flow rate adjustment valve 14 of the cooling device 13 in order to gradually adjust the temperature of the hot water W in the pipe 6. When the measured temperature PV of the hot water W is input from the thermometer 10, the PID control unit 21 performs PID control so that the temperature of the hot water W gradually approaches a preset temperature SV, and the control signal is Output to the flow control valve 14. The value of the set temperature SV is stored in the storage unit 25, and the PID control unit 21 acquires the value of the set temperature SV from the storage unit 25. The flow rate control valve 14 controls the valve opening degree of the flow rate control valve 14 so that the temperature of the hot water W gradually approaches the set temperature SV based on a control signal from the PID control unit 21, and supplies a predetermined amount of cooling water. Supply to piping 6b. Since the PID control performed in this embodiment uses a known technique, detailed description is omitted.

  The detection unit 22 is a part that continuously detects the deviation of the measured temperature PV of the hot water W from the set temperature SV of the hot water W in the pipe 6. When the measurement temperature PV of the hot water W is input from the thermometer 10, the detection unit 22 detects a deviation of the measurement temperature PV with respect to a predetermined set temperature SV and outputs the detected deviation to the determination unit 23. The “deviation” here is specifically a value obtained by subtracting the set temperature SV from the measured temperature PV. When the measured temperature PV is higher than the set temperature SV, the deviation becomes plus (positive) and vice versa. In addition, when the measured temperature PV is lower than the set temperature SV, the deviation becomes minus (negative) (see FIG. 4A).

  The determination unit 23 is a part that determines whether the positive / negative (plus / minus) of the deviation detected by the detection unit 22 is reversed. The determination unit 23 receives the deviation continuously output from the detection unit 22, specifies the positive / negative of two consecutive deviations, and whether the positive / negative of these deviations is inverted, that is, whether the positive or negative has changed from negative to positive. Determine whether. If the determination unit 23 determines that the sign of the deviation has been reversed, the information indicating whether the sign of the deviation has been reversed, including information on whether the sign has been reversed from plus to minus or from minus to plus, is suddenly changed. Output to the control unit 24. When it is determined that the sign of the deviation is reversed, it is determined that the specific condition described above is met.

  The abrupt change control unit 24 temporarily stops the PID control by the PID control unit 21 when the determination unit 23 determines that the sign of the deviation is reversed, and the valve opening degree of the flow rate adjustment valve 14 of the cooling device 13 is This is a portion for executing sudden change control in which the change is abruptly changed by a predetermined opening degree α (for example, a change width of 10%). The abrupt change control unit 24 determines that the measured temperature PV has become lower than the set temperature SV (ie, the deviation has been changed from positive to negative) by determining whether the deviation is positive or negative. The amount of cooling water supplied is drastically reduced by rapidly changing the valve opening of 14 so that the valve opening is reduced by a predetermined opening α. Thereby, the temperature raising operation for raising the temperature of the hot water W is executed.

  On the other hand, the sudden change control unit 24 determines that the measured temperature PV is higher than the set temperature SV (that is, that the deviation is changed from minus to plus) by the reversal determination of the deviation. The supply amount of the cooling water is rapidly increased by abruptly changing the valve opening of the control valve 14 so that the valve opening is increased by a predetermined opening α. Thereby, the temperature lowering operation for lowering the temperature of the hot water W is executed. As described above, the sudden change control unit 24 rapidly determines the opening degree of the flow rate control valve 14 by a predetermined opening degree α after the determination unit 23 determines that the sign of the deviation is reversed (for example, within 1 second). ) Execute sudden change control to be changed. Then, after executing any of the sudden change control described above, the sudden change control unit 24 immediately cancels the stop of the PID control by the PID control unit 21 and performs the PID control by the PID control unit 21 again. In addition, the valve opening degree of the flow rate control valve 14 after the sudden change control is 100% at the maximum and 0% at the minimum.

  Note that the change amount α of the valve opening degree of the flow rate control valve 14 applied to the sudden change control performed by the sudden change control unit 24 described above is 0% when the flow rate control valve 14 is fully closed and 100% when the fully open state is 100%. In this case (see FIG. 4B), the opening width corresponding to at least 5% is preferable, and any opening width between 5% and 40% is more preferable.

  Subsequently, a temperature control method by the above-described temperature control device 9 will be described with reference to FIGS. 3 and 4.

  First, in step S1, it is determined whether or not the temperature control (mainly PID control) of the hot water W by the temperature control device 9 is continuously performed. And in step S1, when performing temperature control of the warm water W by the temperature control apparatus 9, it progresses to step S2 and performs PID control by the PID control part 21, and the measured temperature PV of the warm water W becomes set temperature SV. The flow rate adjustment valve 14 of the cooling device 13 is controlled so as to approach (first control step).

  Then, it progresses to step S3 and the deviation of the measurement temperature PV of the warm water W with respect to the setting temperature SV of the warm water W is detected by the detection part 22 (detection step). And it is determined by the determination part 23 whether the positive / negative of the deviation detected at the detection step of step S3 was reversed (step S4; determination step). In step S4, the PID control by the PID control unit 21 is repeated until it is determined that the sign of the deviation is reversed (“NO” in step S4). The repetition of this PID control is represented, for example, as a line of the measured temperature PV between S0 and S1 in FIG.

  Subsequently, in step S4, when it is determined that the sign of the deviation is reversed (for example, when the measured temperature PV line in FIG. 4A becomes S1), the PID control by the PID control unit 21 is stopped. At the same time, sudden change control is executed in which the valve opening degree of the flow rate adjusting valve 14 of the cooling device 13 is rapidly changed by a predetermined opening degree α (step S5; second control step). Such a sudden change control is represented, for example, as a descending line (arrow) of the valve opening V in S1 of FIG. 4B, and the valve opening of the flow rate control valve 14 is reduced by a predetermined opening α. The valve opening is rapidly changed so as to be the valve opening, and the supply amount of the cooling water is rapidly reduced. Thereby, the temperature raising operation for raising the temperature of the hot water W is executed.

  After executing the sudden change control in step S5, the process returns to step S1 (YES) and step S2 again, immediately stops the PID control by the PID control unit 21 and performs the PID control by the PID control unit 21 again. (Refer to the line of the measured temperature PV between S1 and S2 in FIG. 4A). Then, until it is determined in step S1 that the temperature control of the hot water W is not performed by the temperature control device 9 (refer to the lines of the measured temperature PV and the valve opening degree V after S2 in FIGS. 4A and 4B). ), PID control by the PID control unit 21 and sudden change control by the sudden change control unit 24 are repeatedly performed. Thereafter, when it is determined in step S1 that the hot water control of the hot water W is to be ended, the temperature control process is ended.

  As described above, according to the temperature control device 9 according to the present embodiment, when it is determined that the sign of the deviation of the measured temperature PV with respect to the set temperature SV of the hot water W to be controlled is reversed, the PID control is temporarily stopped. At the same time, sudden change control is executed in which the valve opening degree of the flow rate adjusting valve 14 of the cooling device 13 is suddenly changed by the opening degree α. For this reason, it is possible to correct the valve opening degree of the flow rate control valve 14, which tends to be too open or too close at the time when the sign of the deviation of the measured temperature PV with respect to the set temperature SV is reversed, to an appropriate opening degree at an early stage. . As a result, it is possible to quickly stabilize the temperature of the hot water W to be controlled to the predetermined set temperature SV by simple means such as sudden change control.

  In other words, if it is attempted to adjust the temperature or the like of the hot water W supplied to the jacket 3 only by normal PID control, the temperature of the hot water W or the like is easily disturbed if the supply amount of the cooling water or the like fluctuates due to disturbance or the like. In addition, the temperature of the reactor 2 may be hunted. Furthermore, the temperature of the reactor 2 itself may deviate from the set temperature SV for some reason. In such a case, in order to stabilize the temperature or the like of the hot water W, since the fluctuation of the measured temperature PV is large as shown in FIG. 5, a considerable time is required. If you have to adjust it, it will come out. However, according to the temperature control device 9 according to the present embodiment, as shown in FIG. 4, for example, the temperature adjustment of the hot water W is basically performed by the PID control, and the set temperature SV of the hot water W is adjusted. When the deviation of the measured temperature PV is reversed from minus to plus or from plus to minus, the valve opening degree of the flow rate control valve 14 is suddenly opened or closed abruptly by the opening degree α at that time. Stable temperature control can be performed without being greatly affected by disturbance factors.

  Further, in the temperature control device 9 according to the present embodiment, the sudden change control unit 24 determines that the measured temperature PV is lower than the set temperature SV by determining whether the deviation is positive or negative. 14 is performed so that the temperature of the hot water W is raised by changing the valve opening of the valve 14 so that the valve opening is reduced by a predetermined opening α, and the measured temperature PV is determined by determining whether the deviation is reversed. Is determined to be higher than the set temperature SV, the valve opening degree of the flow rate control valve 14 is changed so as to become a valve opening degree that is larger by a predetermined opening degree α to lower the temperature of the hot water W. The temperature lowering operation is executed. For this reason, it is possible to reliably execute the stabilization of the temperature of the hot water W at the set temperature SV at an early stage.

  Further, in the temperature control device 9 according to the present embodiment, the sudden change control unit 24 executes the sudden change control, then cancels the stop of the PID control by the PID control unit 21, and performs the PID control again. . As described above, after the valve opening degree of the flow rate control valve 14 that tends to be too open or closed when the positive / negative deviation of the measured temperature PV with respect to the set temperature SV is reversed, the PID control is performed again. Therefore, the temperature of the hot water W can be stabilized at the set temperature SV earlier.

  As mentioned above, although this invention was concretely demonstrated based on the embodiment, this invention is not limited to the said embodiment. For example, in the above embodiment, from the viewpoint of cost and ease of handling, the temperature raising device 11 or the cooling device 13 uses steam or cooling water, and these are directly mixed into the circulating hot water W to adjust the temperature. However, the temperature of the hot water W may be indirectly adjusted using a brine heater, an oil heater, an electric heater or the like as the temperature raising device 11 or the like. Further, one of the temperature raising device 11 and the cooling device 13 may always be supplied or indirectly contacted with the hot water W whose temperature is adjusted, and the other may be supplied or indirectly contacted as necessary. Further, one of the temperature raising device 11 and the cooling device 13 may always be supplied or indirectly contacted with the hot water W whose temperature is adjusted, and both may be supplied or indirectly contacted as necessary ( Commonly called split type control valve).

  Further, a system in which a fluid whose temperature is adjusted (hot water W or the like) may be recirculated, or a one-pass type system in which recirculation is not performed. In the recirculated system, only the piping may be circulated without installing a stock tank such as the hot water tank 4 in the middle of the circulation path. However, the provision of a stock tank is preferable in terms of cost because the temperature of the fluid can be easily adjusted. When a stock tank is provided, the fluid supplied to the fluid whose temperature is adjusted in the stock tank or the device that is indirectly contacted always supplies or indirectly contacts the stock tank with a certain amount of temperature rising fluid or cooling fluid. It is desirable to make it.

  In addition, it is desirable that the fluid supplied to the fluid to be temperature-controlled or the device for indirect contact is a device or specification in which the temperature is uniformly mixed or heat-dispersed at the portion that comes into contact with the fluid so that the temperature becomes uniform. It is desirable to select a location that does not adversely affect the measurement point. The temperature rise and cooling are preferably performed by adjusting the temperature by directly mixing using the same fluid. Here, it is preferable that the fluid to be supplied or indirectly contacted with the thermometer of the fluid to be measured is installed as close as possible, but the temperature is determined by the fluid to be supplied or indirectly contacted as necessary. Since a temperature change occurs in the fluid to be adjusted, it is preferable to set a distance at which the temperature can be measured when the temperature of the fluid is reliably uniform. It is preferable to install a line mixer or the like at the point where the fluid is in contact with the fluid supplied or contacted as necessary. Moreover, it is desirable to install the thermometer used for temperature adjustment downstream from the supply point of the fluid that is supplied or indirectly contacted with the flow direction of the fluid as necessary.

  Further, when the temperature rising fluid from the temperature raising device 11 or the cooling fluid from the cooling device 13 is the same as the fluid whose temperature is adjusted, it is preferable that the fluid pressure is higher than the fluid whose temperature is adjusted. . As a method for incorporating the temperature control system according to the present invention into a general feedback control system, a relay type control system in which a sequence program is separately incorporated may be adopted, but the most economical and complicated is required. As a method not to be performed, there is a method using a sequence table of a distributed instrumentation control system generally used in industrial and chemical plants.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.

  In the present embodiment, the system having the configuration shown in FIG. 1 is used, the temperature of the hot water W in the jacket 3 attached to the reactor 2, which is a polypropylene polymerization reactor, is controlled by the temperature control device 9, and the inlet of the jacket 3 is used. The time (minutes) until the nearby measurement temperature PV reached the set temperature SV and stabilized was confirmed. In this example, the standard for determining that “the measurement temperature PV is stable” is that the measurement temperature PV reaches the set temperature SV and the fluctuation width of the measurement temperature PV is 1 ° C. or less, or the measurement temperature Even when the fluctuation width of PV was 1 ° C. or more, the period of fluctuation of the measurement temperature PV was constant.

  In this example, the following experiment was performed in order to confirm that the temperature control system or the temperature control method according to the present invention is quicker than general PID control and the subsequent temperature is stabilized. That is, using the temperature control device 9 according to the present invention, after the thermometer 10 before the entrance of the jacket 3 is once stabilized at a certain temperature, the set temperature SV of the jacket 3 is set to + 2 ° C., then −2 ° C. The controllability of the inlet temperature of the jacket 3 by the temperature controller 9 when the temperature was changed to plus 4 ° C. and then minus 4 ° C. (time until reaching the set temperature SV) was confirmed.

As the reactor 2 used in this experiment, a vessel type reactor with a capacity of 160 L and a stirrer was used. Moreover, the temperature control equipment of the jacket 3 by hot water circulation is made into the following specification. First, the hot water W employs a recirculation temperature adjustment method, and the circulation pump 5 is a spiral pump manufactured by Ebara Corporation. The capacity of the pump 5 was 10 m ³ / hour, the head was 16 m, and the size of the piping 6 of the hot water circulation line was 1 · 1/2 inch. The discharge pressure of the pump 5 was 0.14 MPa-G. An overflow-type hot water tank 4 was installed in the middle of the hot water circulation. The tank capacity of the hot water tank 4 was 450 L, and constant steam was always supplied to the hot water tank 4.

  The steam flow control valve 12 is a control valve manufactured by Motoyama Engineering Co., Ltd., with a coefficient of CV of 9.0 EQ% indicating the flow characteristics of the valve, steam piping of 3 / 4B, and upstream pressure of 0. It was 3 MPa-G. During this test, the steam valve opening was always 80%. The temperature of the circulating hot water W is adjusted by supplying cooling water from the cooling device 13, and the cooling water flow control valve 14 is manufactured by YAMATAKE Co., Ltd., and CV = 9.0 EQ%. The pipe size was 1 inch, and the upstream pressure was 1.0 MPa-G. This cooling water flow rate adjustment valve 14 was used as a specification of the temperature control device 9 to confirm the controllability of temperature adjustment. As the temperature control device 9 used in this example, an instrument incorporated in Micro Excel, which is a middle model of a distributed instrumentation control system manufactured by Yokogawa Electric Corporation, was used. Further, the program control described above was created using a sequence table similarly incorporated in the microexcel.

Example 1
In the above temperature control system, butane 44L was charged into the reactor 2, and the cooling water was supplied and controlled using the temperature controller 9 according to the present invention so that the inlet temperature of the jacket 3 was 70 ° C. The PID values of the PID control regulator of the temperature control device 9 were P = 150, D = 20, and I = 1. At this time, the change amount α of the valve opening that is suddenly changed (abrupt change control) when the deviation between the set temperature SV of the jacket 3 and the measured temperature PV changes from plus to minus or from minus to plus is defined in the first embodiment. 80%. First, after the temperature of the warm water W was stabilized at 70 ° C., the set temperature SV was changed to 72 ° C., and the temperature raising time (minute) until the measurement temperature PV of the warm water W was stabilized at 72 ° C. was confirmed. After collecting this data, the set temperature SV was returned to 70 ° C., and the temperature lowering time (min) until the measured temperature PV of the hot water W was stabilized at 70 ° C. was confirmed. As a result, the time required for each temperature to stabilize was 2 minutes for the temperature rising time and 1 minute for the temperature falling time. The temperature fluctuation after temperature stabilization when the set temperature SV is changed from 70 ° C. to 72 ° C. is 1.57 ° C. The temperature fluctuation after temperature stabilization when the temperature is changed from 72 ° C. to 70 ° C. is 1 ° C. or less. Met.

  Similarly, after the temperature of the hot water W was stabilized at 70 ° C., the set temperature SV was changed to 74 ° C., and the temperature rising time (minutes) until the measurement temperature PV of the hot water W was stabilized at 74 ° C. was confirmed. After collecting this data, the set temperature SV was returned to 70 ° C., and the temperature lowering time (min) until the measured temperature PV of the hot water W was stabilized at 70 ° C. was confirmed. As a result, the time required for each temperature to stabilize was 4 minutes for the temperature rising time and 1 minute for the temperature falling time. The temperature fluctuation after temperature stabilization when the set temperature SV is changed from 70 ° C. to 74 ° C. is 2.1 ° C., and the temperature fluctuation after temperature stabilization when the setting temperature SV is changed from 74 ° C. to 70 ° C. is 1.92. ° C.

(Example 2)
The temperature rise time and the temperature fall time were confirmed under the same conditions as in Example 1 except that the valve opening change width α for changing the valve opening of the flow rate control valve 14 to 60% was changed to 60%. As a result, when the set temperature SV is changed between 70 ° C. and 72 ° C., the time required for each temperature to stabilize is 2 minutes for the temperature rise time and 1 minute for the temperature fall time. there were. The temperature fluctuation after temperature stabilization when the set temperature SV is changed from 70 ° C. to 72 ° C. is 1.31 ° C., and the temperature fluctuation after temperature stabilization when the temperature is changed from 72 ° C. to 70 ° C. is 1 ° C. or less. Met. When the set temperature SV is changed between 70 ° C. and 74 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 2 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization when the set temperature SV is changed from 70 ° C. to 74 ° C. is 1.5 ° C., and the temperature fluctuation after temperature stabilization when the setting temperature SV is changed from 74 ° C. to 70 ° C. is 1.48. ° C.

(Example 3)
The temperature rise time and the temperature fall time were confirmed under the same conditions as in Example 1 except that the valve opening change width α for suddenly changing the valve opening degree of the flow control valve 14 was changed to 40%. As a result, when the set temperature SV is changed between 70 ° C. and 72 ° C., the time required for each temperature to stabilize is 2 minutes for the temperature rise time and 1 minute for the temperature fall time. there were. When the set temperature SV was changed from 70 ° C. to 72 ° C. and when the set temperature SV was changed from 72 ° C. to 70 ° C., the temperature fluctuation after temperature stabilization was 1 ° C. or less. When the set temperature SV is changed between 70 ° C. and 74 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 3 minutes for the temperature fall time. It was. In addition, when the set temperature SV was changed from 70 ° C. to 74 ° C. and when the set temperature SV was changed from 74 ° C. to 70 ° C., the temperature fluctuation after temperature stabilization was 1 ° C. or less.

Example 4
The temperature rise time and the temperature fall time were confirmed under the same conditions as in Example 1 except that the valve opening change width α for changing the valve opening of the flow rate control valve 14 to 20% was changed to 20%. As a result, when the set temperature SV is changed between 70 ° C. and 72 ° C., the time required for each temperature to stabilize is 2 minutes for the temperature rise time and 3 minutes for the temperature fall time. there were. When the set temperature SV is changed between 70 ° C. and 74 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 4 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

(Example 5)
The temperature rise time and the temperature fall time were confirmed under the same conditions as in Example 1 except that the valve opening change width α for rapidly changing the valve opening degree of the flow rate control valve 14 was changed to 10%. As a result, when the set temperature SV is changed between 70 ° C. and 72 ° C., the time required for each temperature to stabilize is 2 minutes for the temperature rise time and 6 minutes for the temperature fall time. there were. When the set temperature SV is changed between 70 ° C. and 74 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 10 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

(Example 6)
The temperature rise time and the temperature fall time were confirmed under the same conditions as in Example 1 except that the valve opening change width α for suddenly controlling the valve opening degree of the flow rate control valve 14 was changed to 5%. As a result, when the set temperature SV is changed between 70 ° C. and 72 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 10 minutes for the temperature fall time. there were. Further, when the set temperature SV is changed between 70 ° C. and 74 ° C., the time required for each temperature to stabilize is 6 minutes for the temperature rise time and 13 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

(Example 7)
Example 1 except that the initial set temperature SV of the hot water W is set to 60 ° C. and the change amount α of the valve opening for controlling the valve opening of the flow rate control valve 14 is changed to 20%. The temperature rise time and the temperature fall time were confirmed under the same conditions. As a result, when the set temperature SV is changed between 60 ° C. and 62 ° C., the time required for each temperature to stabilize is 2 minutes for the temperature rise time and 6 minutes for the temperature fall time. there were. Further, when the set temperature SV is changed between 60 ° C. and 64 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 5 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

(Example 8)
The temperature rise time and the temperature fall time were confirmed under the same conditions as in Example 7 except that the valve opening change width α for suddenly changing the valve opening degree of the flow rate control valve 14 was changed to 5%. As a result, when the set temperature SV is changed between 60 ° C. and 62 ° C., the time required for each temperature to stabilize is 3 minutes for the temperature rise time and 10 minutes for the temperature fall time. there were. Further, when the set temperature SV is changed between 60 ° C. and 64 ° C., the time required for each temperature to stabilize is 5 minutes for the temperature rise time and 19 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

(Comparative Example 1)
As a comparative example, the temperature rise time and the temperature fall time when general PID control was performed were confirmed. Specifically, the temperature rise time and the temperature fall time were confirmed under the same conditions as in Examples 1 to 6 except that the valve opening degree of the flow rate control valve 14 was not controlled to change suddenly. As a result, when the set temperature SV is changed between 70 ° C. and 72 ° C., the time required for each temperature to stabilize is 10 minutes for the temperature rise time and 17 minutes for the temperature fall time. there were. When the set temperature SV is changed between 70 ° C. and 74 ° C., the time required for each temperature to stabilize is 20 minutes for the temperature rise time and 24 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

(Comparative Example 2)
As another comparative example, the temperature rise time and the temperature fall time were confirmed under the same conditions as in Examples 7 and 8, except that the valve opening degree of the flow rate control valve 14 was not controlled to change suddenly. As a result, when the set temperature SV is changed between 60 ° C. and 62 ° C., the time required for each temperature to stabilize is 22 minutes for the temperature rise time and 31 minutes for the temperature fall time. there were. When the set temperature SV is changed between 60 ° C. and 64 ° C., the time required for each temperature to stabilize is 31 minutes for the temperature rise time and 37 minutes for the temperature fall time. It was. The temperature fluctuation after temperature stabilization was 1 ° C. or less.

  As described above, as is clear from the comparison results between Examples 1 to 6 and Comparative Example 1 and the comparison results between Examples 7 and 8 and Comparative Example 2, the temperature control using the temperature control device 9 according to the present invention. According to the above, the temperature of the target fluid can be stabilized at the predetermined set temperature SV in about one-tenth of the time compared to the case of temperature control using only general PID control. In addition, when the valve opening degree of the flow control valve 14 is 5% to 40%, the temperature fluctuation after the temperature stabilization is within 1 ° C., and the temperature of the target fluid can be stabilized.

  Subsequently, as an embodiment different from the above, the present invention is applied to cascade control for adjusting the temperature of the polypropylene polymerization reaction tank by circulating the temperature-controlled hot water through a jacket attached to the polypropylene polymerization reaction tank. The temperature control method according to was applied. In this example, polypropylene is an organic aluminum (hereinafter referred to as triethylaluminum) that is a reaction accelerator for a general Ti—Mg type solid catalyst, and an organic silicon compound (hereinafter referred to as “triethylaluminum”). Cyclohexylethyldimethoxysilane), and a method obtained by polymerization reaction in liquefied propylene.

Example 9
First, an apparatus having a configuration similar to the apparatus shown in FIG. 1 was prepared as a temperature adjustment facility for the hot water W for adjusting the temperature of the polymerization reaction tank and the polymerization reaction tank. In this apparatus, the reaction tank 2 was a vessel type reaction tank with a stirrer having a volume of 40 L. The reaction tank 2 has a jacket 3 and the polymerization temperature is controlled by passing warm water W through the jacket 3. There are several reaction tanks in addition to this reaction tank 2, and these reaction tanks may be connected to carry out series polymerization. Since this reaction tank 2 is used for the first tank, it is installed on the fourth floor of the plant. did.

Moreover, the temperature adjustment equipment of the warm water W which adjusts by passing the warm water W through the jacket 3 was installed as follows. For the hot water W, a temperature adjustment method using a recirculation method was adopted. The hot water stock tank 4 was not installed due to problems such as installation space, and the hot water W was circulated only by piping and sent out by the centrifugal pump 5. The circulation pump 5 was a centrifugal pump manufactured by Nikkiso Co., Ltd., and its capacity was 10 m ³ / hour, and was installed on the first floor.

The size of the hot water circulation line was 1 inch, and the actual flow rate of the hot water W was 7 m ³ / hour. The discharge pressure of the pump was 0.3 MPa-G. In order to replenish the liquid in the circulation line and stabilize the base temperature of the circulating water W, 300 L / hour of industrial water (normal temperature) was supplied as a minimum flow. The following control valves were used for the cooling / heating device. The cooling device was a control valve manufactured by Motoyama, the CV value of which was 3, and the original pressure was 0.7 MPa-G using industrial water. The temperature raising device was a control valve manufactured by Motoyama, and the CV value was 9 and steam was used. The original pressure of the steam was 0.4 MPa-G.

  The cooling / heating device was planned to be installed near the entrance of the jacket 3 attached to the reaction tank 2, but it was installed near the hot water circulation pump 5 due to space problems and equipment maintenance. The specifications to supply to. The distance from the hot water circulation pump 5 to the reaction tank 2 was about 19 m. A thermometer 10 for measuring the circulating hot water was installed near the inlet of the jacket 3.

  The temperature of the circulating hot water W was adjusted by measuring a thermometer 10 installed near the entrance of the jacket 3 and adjusting the temperature by the temperature adjusting system 9 according to the present invention. The output side of the temperature control system 9 of the present invention adjusts the flow rate of the cooling water when the output is 0 to 50%, the valve is fully opened when 0%, and the valve is fully closed when 50%, and 50 to 100% is steam. The flow rate was adjusted, and the temperature was adjusted by controlling the regulating valve with a so-called split type that was fully closed at 50% and fully opened at 100%. The temperature control system of the reaction vessel 2 used a general PID feedback automatic control instrument.

  The temperature control system 9 implemented in the present embodiment is cascade control including a secondary control system of a reaction tank temperature control system and a hot water temperature control system. The detailed control mechanism is as follows. Cascade control when the temperature difference between the set temperature SV and measured temperature PV of the thermometer 10 installed near the jacket 3 is reversed from plus to minus or minus to plus while controlling the reactor temperature in the cascade loop. To program control (sudden change control).

  The cascade loop is canceled by the sequence program, and the hot water control system is switched to manual control. When the indicated value of the thermometer 10 installed in the vicinity of the jacket 3 became high, the cooling operation by the cooling facility or the operation of lowering the temperature by the decrease of the heat source supplied by the temperature raising facility was performed. When the indicated value was low, the temperature was increased by decreasing the amount of cooling supplied by the cooling facility or by supplying the heat source using the temperature raising facility. Then, immediately after these operations, temperature control was performed by switching again to automatic feedback control and further to cascade control with the reaction vessel temperature control system.

  The cooling water / steam valve is adjusted for cooling / heating, but when the deviation between the set temperature SV and the measured temperature PV is reversed from plus to minus or from minus to plus, the valve opening of the temperature control valve is 10%. Was operated from the valve opening degree when the deviation was reversed from plus to minus or from minus to plus in the direction in which the hot water temperature cooled or raised.

  The PID value of the primary control system on the reaction tank side is P = 250, I = 90, and D = 2, and the PID set values of the secondary control system on the hot water side are P = 180, I = 15, D = 1 was entered. The temperature control instrument used in this example was an instrument incorporated in Micro Excel, which is a middle model of the distributed instrumentation control system manufactured by Yokogawa Electric Corporation. Further, the program control described above was created using a sequence table similarly incorporated in the microexcel.

[Preparation of Ti-Mg type solid catalyst]
First, a 200-liter SUS reaction vessel equipped with a stirrer was replaced with nitrogen, and then dehydrated and degassed hexane 80 L, tetrabutoxy titanium 6.55 mol, diisobutyl phthalate 2.8 mol, and tetraethoxysilane 98. Nine moles were added to obtain a uniform solution. Next, 51 L of a diisobutyl ether solution of butyl magnesium chloride having a concentration of 2.1 mol / L was gradually added dropwise over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of the dropping, the mixture was stirred at room temperature for 1 hour, separated into solid and liquid at room temperature, and then washed with 70 L of toluene three times.

  Subsequently, toluene was added so that the slurry concentration became 0.2 kg / L, 47.6 mol of diisobutyl phthalate was added, and the reaction was performed at 95 ° C. for 30 minutes. After the reaction, it was separated into solid and liquid and washed twice with toluene. Next, 3.13 mol of diisobutyl phthalate, 8.9 mol of butyl ether and 274 mol of titanium tetrachloride were added, and the reaction was carried out at 105 ° C. for 3 hours. After completion of the reaction, solid-liquid separation was performed at the same temperature, and washing was performed twice with 90 L of toluene at the same temperature.

  Subsequently, after adjusting the slurry concentration to 0.4 Kg / L, 8.9 mol of butyl ether and 137 mol of titanium tetrachloride were added, and the reaction was performed at 105 ° C. for 1 hour. After completion of the reaction, solid-liquid separation was performed at the same temperature, followed by washing with 90 L of toluene three times at the same temperature, then further washing with 70 L of hexane three times and drying under reduced pressure to obtain 11.4 kg of a solid catalyst component. The titanium atom content of the solid catalyst component was 2.1% by weight.

[Preparation of prepolymerization catalyst]
While stirring, 1 L of n-hexane that had been dehydrated and degassed was charged into an SUS autoclave with a stirrer having an internal volume of 3 L, the liquid temperature was kept at 4 ° C., and 25.0 mmol of triethylaluminum was added. Thereafter, 1.25 mmol of cyclohexylethyldimethoxysilane was added. Furthermore, 12.7 g (5.57 mmol in terms of titanium atom) of the Ti—Mg solid catalyst was added and contact-treated. Next, propylene was continuously supplied, and a total of 12.7 g was supplied over 30 minutes while maintaining the liquid temperature at 4 to 7.3 ° C.

  Aging was carried out for 30 minutes to obtain a slurry of a prepolymer (hereinafter referred to as prepolymerization catalyst). A part of the prepolymerized catalyst was taken out from the slurry and subjected to deashing treatment, and the ratio of polypropylene in the prepolymerized catalyst was determined. As a result, it was 1.0 g-polypropylene / g-solid catalyst.

[Main polymerization and temperature control]
The inside of the reaction vessel 2 made of SUS with a stirrer with an internal volume of 40 L was replaced with propylene, and then, while maintaining the polymerization system at 70 ° C., propylene was 35 kg / hour, hydrogen was 315 L / hour, and triethylaluminum was 41.6 mmol / hour. Then, 6.07 mmol / hour of cyclohexylethyldimethoxysilane was continuously supplied, the liquid level in the system was set to 18 L, and a dummy operation was started. When the inside of the polymerization system was stabilized, 0.96 g / hour was continuously supplied using the slurry of the prepolymerized catalyst as a prepolymerized catalyst. The residence time was 0.23 hours, the pressure was 3.39 MPa, and polypropylene was obtained at 4.0 kg / hour by polymerization. Polypropylene and unreacted material were discharged intermittently.

  Here, as described above, the temperature control of the reaction vessel 2 was performed by the temperature control method according to the present invention. When the temperature of the reaction tank 2 is controlled by a cascade loop using the PID control controller according to the present invention, the supply amount of the prepolymerization catalyst becomes unstable due to a malfunction of the supply pump, and the tank temperature may be disturbed. However, it converged to the set reaction temperature of 70 ° C., and stable operation could be continued.

(Comparative Example 3)
[Main polymerization and temperature control]
As a comparative example of Example 9, the temperature adjustment of the jacket warm water is performed by feedback automatic control by a general PID calculation, and P = 50 to 500, I = 0 to 50, A temperature control similar to that in Example 9 was performed except that the adjustment was made in the range of D = 0 to 200. In Comparative Example 3, although the supply amount of the catalyst was stable, hunting of the polymerization tank temperature became large, and temperature adjustment was impossible without human intervention.

  DESCRIPTION OF SYMBOLS 1 ... Chemical plant, 2 ... Reactor, 3 ... Jacket, 4 ... Hot water tank, 5 ... Pump, 6, 6a, 6b ... Pipe, 7 ... Reactor temperature output part, 8 ... Thermometer, 9 ... Temperature controller, 10 ... Thermometer, 11 ... Temperature raising device, 12 ... Flow control valve, 13 ... Cooling device, 14 ... Flow control valve, 21 ... PID controller, 22 ... Detector, 23 ... Determiner, 24 ... Abrupt change controller, W ... Hot water.

Claims (5)

A temperature control system for adjusting the temperature of a target fluid to a predetermined set temperature SV,
At least one of a cooling device and a temperature raising device for adjusting the temperature of the target fluid;
First control means for performing feedback automatic control on at least one of the cooling device and the temperature raising device to adjust the temperature of the target fluid;
Detecting means for detecting a deviation of the measured temperature PV of the target fluid from a set temperature SV of the target fluid;
Determination means for determining whether the sign of the deviation detected by the detection means is reversed;
When the determination means determines that the sign of the deviation has been reversed, the automatic feedback control by the first control means is stopped, and the temperature control valve of at least one of the cooling device and the temperature raising device is opened. Second control means for performing sudden change control for rapidly changing the degree by a predetermined opening degree;
A temperature control system comprising:   When the second control means determines that the measured temperature PV is lower than the set temperature SV based on the positive / negative reversal determination of the deviation, the second control means opens the valve opening degree of the temperature control valve to a predetermined value. A temperature raising operation is performed to increase the temperature of the target fluid by changing the valve opening to be smaller by a certain amount, and the measured temperature PV becomes higher than the set temperature SV by the positive / negative reversal determination of the deviation. When it is determined that the temperature of the target fluid is lowered, the temperature of the target fluid is decreased by changing the valve opening of the temperature control valve so that the valve opening is larger by a predetermined opening. The temperature control system according to claim 1. The predetermined opening is an opening width corresponding to at least 5% when the fully closed state of the temperature control valve is 0% and the fully opened state is 100%,
The second control means suddenly changes the valve opening degree of the temperature control valve by the predetermined opening degree within one second after the judgment means judges that the sign of the deviation is reversed. The temperature control system according to claim 1, wherein the temperature control system is executed.   4. The temperature control system according to claim 1, wherein the second control unit cancels the stop of the automatic feedback control by the first control unit after executing the sudden change control. 5. . In a temperature control system including at least one of a cooling device and a temperature raising device for adjusting the temperature of a target fluid, a temperature control method for adjusting the temperature of the target fluid to a predetermined set temperature SV,
A first control step of performing feedback automatic control on at least one of the cooling device and the temperature raising device to adjust the temperature of the target fluid;
A detection step of detecting a deviation of the measurement temperature PV of the target fluid with respect to a set temperature SV of the target fluid;
A determination step of determining whether the sign of the deviation detected in the detection step is reversed;
When it is determined in the determining step that the sign of the deviation is reversed, the feedback automatic control in the first control step is stopped, and the temperature control valve of at least one of the cooling device and the temperature raising device is opened. A second control step for executing a sudden change control for rapidly changing the degree by a predetermined opening;
A temperature control method comprising:

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