JPS6242202A - Method for controlling internal temperature of reactor - Google Patents

Abstract

PURPOSE:To control accurately the internal temperature of a reactor to an optimum level by using the result of integration of the difference between a detection pattern and a reference pattern of the internal temperature of the reactor as a function of evaluation to correct a control parameter and performing the control of the jacket temperature. CONSTITUTION:The internal temperature of a reactor 1 is detected by an internal temperature detecting terminal 11. An arithmetic part 12 obtains the difference between the detected internal temperature and a reference internal temperature pattern stored in a storage part 13 and gives it to a pattern control part 40 and a sequence control part 18. The part 40 integrates the given difference to obtain a function of evaluation and sets a jacket temperature control pattern directly when the absolute value of said function is smaller than the threshold value and via the parameter correction when the absolute value is larger than the threshold value respectively. While the part 18 synthesizes the synthetic value of the given difference and the bias value of the jacket temperature given from a bias control part 20 with the temperature control pattern given from the part 40 and gives this synthetic value to a jacket temperature controller 7. Then the controller 7 defines the given synthetic value as the set value and controls the opening amounts of both valves 5 and 6.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for controlling the internal temperature of a reactor.

Specifically, the present invention relates to a method of controlling the internal temperature to an appropriate value using a learning function when increasing the temperature of a batch reactor in which the internal temperature is controlled at 4 degrees Celsius.

[Foreground technology and its problems]

The internal temperature of the polymerization reactor and the like is controlled by cascade feedback control that is controlled by jacket temperature.

In such a process, there is a time delay of Bto from when the jacket temperature is changed until the internal temperature responds, and feedback control tends to result in overcontrol. As a result, the jacket temperature fluctuates greatly and the reactor Internal temperature tends to become unstable.

In addition, in this type of controlled wholesale, the operator determines parameters such as the jacket temperature adjustment amount, temperature change rate, and temperature switching setting time based on experience, and operates with manual settings. Therefore, there were large individual differences in temperature control due to differences in operator skill.

[Purpose of the invention]

The purpose of the present invention is to eliminate these conventional drawbacks, suppress large fluctuations in jacket temperature, eliminate differences due to operator skill, and accurately control the internal temperature of the reactor to the optimum value. The object of the present invention is to provide a method for controlling the internal temperature of a reactor.

[Means and effects for solving the problem] In the present invention, the internal temperature of the reactor is detected, the difference between this internal temperature detection pattern and a preset internal temperature reference pattern of the reactor is integrated, and the internal temperature of the reactor is integrated. The above objective is achieved by modifying the control parameters using the results as evaluation functions and controlling the jacket temperature based on the control parameters.

Therefore, the method of the present invention will be specifically described using FIG. Figure 1 shows the jacket temperature control surface 1 (
jacket temperature control pattern).

That is, in order to control the actual internal temperature of the reactor to the internal temperature reference pattern, the jacket temperature control pattern is first rapidly increased, and after reaching the temperature PvII, the jacket temperature control pattern is
1. When the internal temperature reaches the heating point PV, the temperature is lowered by the temperature adjustment amount ΔSV, and after the set time t1 has elapsed, the temperature is rapidly lowered by the set amount dsV/dt, and then gradually It turns out that it is best to use a pattern that causes the value to rise.

In controlling the internal temperature of the reactor, the exothermic point PVA
(the jacket temperature is below temperature P from the start of temperature rise)
Although the control of the temperature increase area A until reaching temperature v and the constant temperature area B that maintains temperature PV is not so important, it is important to control the temperature increase area above the heat generation point PvA (set after the internal temperature reaches the heat generation point PVa). Section C and t up to time t1
Section D from l to time t2 when the internal temperature reaches the saturation point
) is extremely important from the viewpoint of preventing abnormal reactions and the like.

Temperature control in section C is performed using the temperature adjustment amount ΔSV.
Temperature control in the sections is carried out by a temperature change rate dsV/dt, and temperature control in sections C and D is carried out by a set time period.

However, in the past, these parameters were manually set by operators based on their experience, resulting in individual differences in temperature control.

The present invention calculates an evaluation function obtained by integrating the difference between the actual internal temperature of the reactor and a reference pattern for each section, and corrects the control parameters for each section according to the evaluation function for each section. This is what I am trying to do.

That is, if the internal temperature detection pattern detected from the reactor is T1, and the internal temperature reference pattern in section C (tO to 1+) is T,', then the evaluation function J1 in section C can be found as follows. If the absolute value IJ11 of the evaluation function J + found in this way exceeds the preset threshold ε1, the temperature adjustment amount ΔSV is corrected, and if it is below the threshold ε, the temperature Adjustment amount ΔS
■ will be kept as is.

Now, as shown in Fig. 2, if the evaluation function J1 is 10 and its absolute value IJ11 exceeds the threshold value ε, the temperature adjustment amount ΔSV is too small, so it is necessary to increase it. Correct. For example, the evaluation function and temperature adjustment amount for the n-th batch processing are J, 1. ΔSV2
, when the constant is β, the temperature adjustment amount ΔSV, ,,,, during the next batch processing is Δ3 V (sel+ =
ΔS V l1l) ” J I+n+ 'β is corrected and set. Therefore, in the next batch processing, the section C
Since the detection pattern of the internal temperature decreases and the base 4 approaches the pattern TR', the internal temperature can be controlled to the target value.

Further, if the internal temperature reference pattern of the interval D (t+ ~ tz) is T,'', the evaluation function J2 in the interval can be obtained as follows.The absolute iftlJgl of the evaluation function J2 obtained by this is If the temperature change rate dSV exceeds the threshold value ε2
/dt is modified, and if the temperature change rate dSV/dt is below the threshold value 62, the temperature change rate dSV/dt is maintained as it is.

Now, as shown in FIG. 3, if the evaluation function Jt is 10 and its absolute value I J 21 exceeds the threshold value ε, the temperature change rate dSV/dt is too small. For example, the evaluation function and temperature change rate during the nth batch processing are J z
+A) , d S V C++l / d t, when the constant is T, the temperature change rate d during the next hatching process
S V +n++l/dt is modified and set to. Therefore, in the next batch process, the internal temperature detection pattern in the section decreases and approaches the reference pattern T,'', so that the internal temperature can be controlled to the target value.

Furthermore, the absolute value IJ11 . 1J2
1 exceeds the threshold values ε5 and ε2, when the number of corrections K of both parameters reaches the set number M, an evaluation function J3 spanning both sections C and D is determined. Both sections C, D
If the internal temperature reference pattern of (to ~ tz) is TR''', then the evaluation function J in both sections C and D can be obtained as follows.The absolute value IJ of the evaluation function J obtained from this, 1 is a preset threshold ε
, the set time t1 is corrected,
If the threshold value ε3 or less, the set time t is kept unchanged.

Now, as shown in FIG. 4, if the number of evaluation intervals J3 is ten and its absolute value IJ,1 exceeds the threshold value ε, then the set time 1. is too large, so we will modify it to make it smaller. For example, the evaluation function and setting time for the n-th batch process are J. l l LILal, if the constant is δ, the set time t for the next batch processing, (
7゜1. is LIIn・eye=L l+111 +J
Corrected and set to 3 +++1 'δ. When the set time L1 is corrected, in the next batch process, the interval C,
The internal temperature detection pattern over D decreases and approaches the reference pattern. Therefore, from now on, the frequency of correction of the parameters in the section C and the section, that is, the temperature adjustment amount ΔSV and the temperature change rate dSV/dt, can be reduced, and the number of corrections can also be kept within a certain range.

〔Example〕

FIG. 5 shows an example in which the method of the present invention is applied to a reactor. In the figure, the internal temperature of a reactor 1 is regulated by the ratio of steam and cold water supplied into a two-shank 2 installed around the reactor.

The jacket 2 has a circulation path 4 with a circulation pump 3 in the middle.
is connected to this circuit 4, and a jacket temperature controller 7 is connected to this circulation path 4.
Steam and cold water are supplied through a valve 5.6 which is opened and closed by the valve 5.6.

The jacket temperature controller 7 is a jacket temperature detection unit that detects the temperature inside the jacket 2; Adjust.

The internal temperature of the reactor 1, for example, the temperature of the polymer in the reactor 1, is detected by the internal temperature detection end 11 and then sent to the calculation section 12, bias control section 20, and switch switch 31, respectively. In the calculation unit 12, the internal temperature detection Il
The difference between the detected value from l and the internal temperature reference pattern in the storage unit 13 is determined. This difference is given to the pattern control section 40 and, after being instructed to the temperature controller 14, is given to the sequence section 18. The difference given to the sequence control section 18 is combined in the calculation section 15 with the bias value of jacket>L degrees given from the bias control section 20, and then the switch 16 (internal temperature It is turned on at the time t when the detected value reaches the heat generation point PVA), and is combined with the jacket temperature control pattern given from the pattern control section 40 in the calculation section 17, and then the jacket temperature controller 7 given to. Thereby, the salmon 1/temperature controller 7 adjusts the opening degrees of the valves 5 and 6 using this as a set value.

In the bias control section 20, first, the change rate calculation section 21 takes in the internal temperature detection value from the internal temperature detection terminal 11 at a fixed sampling period (for example, 1 to 2 minute period), and calculates the internal temperature at each point in time. Rate of change α (=dPV/dt)
seek. To find the rate of change α, for example, as shown in FIG.
V2, the value of the internal temperature reference pattern is S V+, S
V2, and E+ = P ”/+ S VZE Z = P
VzSVzα=-('C/min or second).

When the internal temperature change rates α1 to α7 at each sample time point thus determined exceed a preset threshold value ε, the bias control unit 22 bias-controls the crystallinity of the jacket.

For example, in FIG. 7(A), the internal temperature change rate α1~
Assuming that α3 exceeds the threshold value ε, Fig. 7(B)
As shown, the jacket temperature is bias-controlled by a value obtained by multiplying each internal temperature change rate α1 to α3 by a constant X.

In addition, as shown in FIG. 8, each sample time point (for example, 3
Among the internal temperature change rates of 0 seconds period), the internal temperature change rate α
. 7. α. . 11. α. . . exceeds the threshold ε, the jacket temperature control pattern is as shown in Figure 8 (B
), the bias is controlled by a value obtained by multiplying these internal temperature change rates by a constant X. Furthermore, by adding cascade output to this, the jacket m degree control pattern becomes the 8th
The result will be as shown in Figure (C).

On the other hand, in the pattern control section 40, according to the flowchart of FIG.
, the temperature change rate dsV/dt, the set time t, and the set number of corrections M are set as initial values, and then the evaluation function J l1nl, Joi, , etc. is determined.

The evaluation function J I f+l, J21. In the evaluation section 42, the absolute value IJI+-11, l
Jz+. i is the threshold value ε9. It is determined whether or not it is larger than ε2.

If the absolute value IJlt-port of the evaluation function Jl<fil is larger than the threshold value ε1, the temperature adjustment amount for the next hatching process is ΔSVL, . 5. =ΔSV+n+ +Jl
+I+1・β(while being corrected, the absolute value IJI., 1
If is less than the threshold value ε1, the temperature adjustment amount for the next batch processing remains unchanged, that is, ΔSVo. 1. −ΔS V
, n.

is maintained.

Also, the evaluation function Jz (absolute value of fil IJt+-+l
When is larger than the threshold value ε2, the temperature change rate during the 9th batch processing is dS''1n-11/dt=dsv.

/dt+J2,・While it is corrected to T, the absolute value IJ
Z (If al l is less than the threshold value 82, the temperature change rate during the next batch processing will remain the same, that is, dsV+
IT, +1 /d t=dsV+n+ /d t is held.

Furthermore, the absolute value IJlf~1 is the threshold value ε.

If the absolute value IJZ(-11 is less than or equal to the threshold value ε1), 1 is added to the number of batch processes n, and then the process returns to calculating the evaluation function.

On the other hand, the absolute value IJ l +fil 1 is greater than the threshold value ε, and the absolute value lJz+. , 1 is larger than the threshold ε2, then the temperature adjustment bond ΔSV
and the number of corrections K for correcting the temperature change rate dSV/dt
It is determined whether or not the number of times M has reached a preset number of times.

If the number of modifications K has not reached the set number M, 1 is added to the number of modifications K, then 1 is added to the batch processing number n, and the process returns to calculating the evaluation function.

When the number of corrections K reaches the set number M, the number of corrections K
After resetting to O, the evaluation function J3(n) is determined.

The evaluation function J 3 +Il+ obtained here is judged by the evaluation unit 42 as to whether or not its absolute value I J y t-+ l is larger than the threshold value ε.

If the absolute value lJs is larger than the threshold value ε, then the set time for the next hatch process is j I twill
l=Ll(fil→J*(Ill・δ), while if the absolute value lJs+n+l is equal to or less than the threshold ε, the set time for the next hatch process remains unchanged, that is, 1°0+ll ” tl +n+ After that, 1 is added to the number of batch processes n, and the process returns to calculating the evaluation function.

Therefore, according to this embodiment, an evaluation function is obtained by integrating the difference between the internal temperature detection pattern of the reactor 1 and the internal temperature reference pattern, and the jacket temperature control parameter is corrected according to this evaluation function. Therefore, unlike the conventional method, the internal temperature of the reactor can be easily and accurately controlled to the optimum value without relying on the operator's experience. Therefore, abnormal reactions in the reactor can be prevented, and labor savings can be achieved by automating the temperature control of the reactor.

In addition, the temperature range in which the internal temperature of the reactor increases is divided, and an evaluation function is obtained for each section. For example, when the absolute value of the evaluation function J in section C in Fig. 1 exceeds the threshold value ε1, , the temperature adjustment amount ΔSV is corrected, and when the evaluation function J2 in the D interval exceeds the threshold value ε2, the temperature change rate dsV/dt is corrected, so that the temperature rise curve of the internal temperature is finely and precisely Can be well controlled.

Furthermore, the absolute values of the re-evaluation functions, J+ and Jz, are determined by their respective thresholds ε1. If ε2 is exceeded and the number of corrections (■) reaches the set number of times fj1M, the evaluation function J is calculated and the set time t1 is corrected according to the absolute value of this evaluation function J. Even when the temperature adjustment amount ΔSV and the temperature change rate dSV/dt are frequently corrected, the set time t1 is corrected each time the set number of times M is reached.
There is no need to perform frequent correction processes thereafter, and the amounts of these corrections can be kept within a certain range.

[Effects of the Invention] As described above, according to the present invention, the internal temperature of the reactor can be accurately controlled to an optimum value without individual differences among operators, while suppressing large fluctuations in jacket temperature.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining the present invention, and the first
The figure shows the relationship between the internal temperature reference pattern and the salmon temperature control pattern, and FIGS. 2 to 4 show the relationship between the evaluation function and parameters in each section. Fifth
9 to 9 show an embodiment of the present invention, FIG. 5 is a block diagram showing the entire system, FIG. 6 is an explanatory diagram for determining the rate of temperature change, and FIG. 7 shows bias control. An explanatory diagram, FIG. 8 is an explanatory diagram showing another example of bias control, and FIG. 9 is an explanatory diagram showing another example of bias control.
The figure is a flowchart showing pattern control of jacket temperature. DESCRIPTION OF SYMBOLS 1... Reactor, 2... Jacket, 40... Pattern control part.

Claims (6)

[Claims] (1) In the method of controlling the internal temperature of the reactor by jacket temperature, the internal temperature of the reactor is detected, and the evaluation function is calculated by integrating the difference between this internal temperature detection pattern and a preset internal temperature reference pattern. A method for controlling an internal temperature of a reactor, comprising: determining a jacket temperature control parameter according to the evaluation function, and controlling the jacket temperature based on the control parameter. (2) In claim 1, the control parameters include a temperature adjustment amount when decreasing the jacket temperature after the internal temperature reaches the heating point, and a set time after the internal temperature reaches the heating point. A method for controlling the internal temperature of a reactor, characterized in that the parameter is at least one of the temperature change rate and the set time when lowering the jacket temperature after the elapse of time. (3) In claim 2, there is a first period from when the internal temperature of the reactor reaches the exothermic point to when a set time has elapsed, and from when the internal temperature reaches the saturation point after the elapse of the set time. Find an evaluation function for each of the second sections up to and correct the temperature adjustment amount according to the evaluation function of the first section, and correct the temperature change rate according to the evaluation function of the second section. A method for controlling the internal temperature of a reactor, characterized by: (4) In claim 3, when the number of corrections of the temperature adjustment amount and temperature change rate reaches a preset number of times, from when the internal temperature reaches a heat generation point until it reaches a saturation point. A method for controlling an internal temperature of a reactor, characterized in that an evaluation function is determined for the third section of , and the set time is corrected in accordance with this evaluation function. (5) The reactor according to any one of claims 1 to 4, characterized in that the control parameters are modified when the evaluation function exceeds a preset threshold. Internal temperature control method. (6) A method for controlling the internal temperature of a reactor according to any one of claims 1 to 5, characterized in that, in the correction, a product of the evaluation function and a constant is added to the previous value.