JPH0527453B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for diagnosing abnormalities in a reaction process in a reactor, and in particular, to a method for diagnosing an abnormality in a reaction process in a reactor, and in particular, a method for diagnosing abnormalities in a reaction process in a reactor. The present invention relates to a method for diagnosing an abnormality in a reactor, which diagnoses an abnormality in a reaction process based on a reaction trajectory centered on .

[Prior art] In batch reactors used in the petrochemical industry, etc., the reaction process is modified in order to maximize the yield of the product for a given amount of feed and to ensure the required purity. Must be maintained in a stable condition. For this purpose, it is particularly important to maintain a stable conversion rate, which determines the physical properties of the reaction product.

However, conventionally, in this type of batch reactor, it is not possible to estimate the conversion rate during the reaction, which determines the physical properties of the reaction product. Physical properties were tested through measurements and other methods.

[Problems to be Solved] As mentioned above, in the past, physical properties were tested by measuring the melt index of the final product, making it impossible to detect changes in the physical properties of the reaction product at an early stage. Therefore, in a batch type polymerization reactor, if a non-standard product is produced, all the products reacted and processed in that batch can no longer be used, resulting in great damage.

The present invention was made in view of the above problems, and uses a reaction model to predict the conversion rate of the raw material, and also measures the temperature of the batch reactor, and determines the reaction state from at least one of the conversion rate and the reactor temperature. That is, the object of the present invention is to provide a method for diagnosing an abnormality in a reaction process in a batch reactor by detecting changes in physical properties of reaction products at an early stage during the reaction.

[Means for Solving Problems] In order to achieve the above object, the method for diagnosing an abnormality in a batch reactor according to the present invention is based on the method for diagnosing an abnormality in a batch reactor. The conversion rate is estimated by substituting at least one measured temperature of the outlet temperature of the heat exchanger into the heat removal rate calculation formula and the conversion rate estimation calculation formula, and this estimation result is determined as the predetermined conversion rate stability zone,
There is a method of diagnosing an abnormality by determining on a display device where the vehicle is located in a warning zone or an unstable zone.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 5.

First, the configuration of an apparatus for carrying out the method of this embodiment will be explained based on FIG.

In FIG. 1, 1 is a batch reactor;
A jacket 2 for controlling the internal temperature of the reactor 1 is provided around it. Reference numeral 3 denotes a supply pipe for supplying a cooling medium to the jacket 2, which exchanges heat with cooling water in a heat exchanger 4 to control the temperature. Reference numeral 5 denotes a flow control valve for temperature control provided in the cooling water supply pipe 6. 7 is a temperature sensor that measures the internal temperature of the reactor 1; 8 is a temperature sensor that measures the temperature of the jacket 2; 9 is a temperature sensor that measures the inlet temperature of the cooling water heat exchanger 4; 10 is a cooling This is a temperature detector that measures the outlet temperature of the water heat exchanger 4, and is input to the estimation calculation device 11.

The estimation calculation device 11 calculates, based on a preset conversion rate estimation calculation formula and a heat removal rate calculation formula,
The conversion rate of the raw material is calculated from the measured values from each temperature detector 7, 8, 9, and 10. This estimation calculation device 11 has a function of calculating the amount of heat removed per unit time in the reactor 1, that is, the heat removal rate, and the amount of heat removed per unit time, that is, the heat removal rate in the jacket 2 of the reactor 1, and the function of calculating the heat removal rate per unit time in the jacket 2 of the reactor 1. It also has a function to calculate the conversion rate, that is, the conversion rate.

Reference numeral 12 denotes a CRT display device which displays the conversion rate calculated by the estimation calculation device 11 and the internal temperature of the reactor 1 and the temperature of the jacket 2 measured by the temperature detectors 7 and 8. Also, CRT
The display device 12 displays the above-mentioned conversion rate and temperature, and at the same time displays the tolerance range for the conversion rate, etc., determined in advance based on design, control results, etc., and the tolerance range for the internal temperature and jacket temperature of the reactor 1, determined in the same way. Display range etc. Although it is common to provide separate CRT display devices 12 for conversion rate and reactor temperature, it is of course possible to use one CRT display device by switching, for example.

Next, the method of the embodiment will be explained with reference to the flowchart shown in FIG.

The internal temperature of the reactor 1, the jacket temperature, and the inlet temperature and outlet temperature of the cooling water heat exchanger 4 are measured by each temperature detector 7, 8, 9, and 10 (step 101 in Fig. 2). ).

The estimation calculation device 11 performs a predetermined calculation based on the temperature measurement value using a preset conversion rate estimation calculation formula and a heat removal rate calculation formula, and calculates the heat removal rate inside the reactor and the heat removal rate in the jacket. The speed is calculated, and the conversion temperature is also calculated (step 102 in FIG. 2).

○ Conversion rate estimation calculation formula γ=dx/dt =K _p exp {−(E _a /rt _a )} (CAT) 〓・(1−X) ……(1) Here, K _p : Frequency coefficient E _a : Activation energy R: Gas constant ○ Heat removal rate inside the reactor (heat removal amount per unit time) Q _J = ΔH・W _R・γ −C _pn・W _T・dT _R /dt ……(2) ○ Heat removal rate in the jacket (amount of heat removed per unit time) Q _J = UA (T _R − T _J ) = C _PC・W _C (T _OUT − T _IN ) ……(3) Above (1) to (3) The symbols in the formula are as follows.

γ: Conversion rate x: Conversion rate CAT: Catalyst concentration α: Constant determined by the reaction system T _R : Rising temperature of reactants T _J : Jacket temperature T _IN : Cooling water inlet temperature T _OUT : Cooling water outlet temperature ΔH: Heat of reaction C _PC : Average specific heat of cooling water Q _J : Heat removal temperature W _R : Amount of reactant W _T : Weight of reactor contents (reactant and catalyst) W _C : Weight of cooling medium C _pn : Average of W _T Specific heat U: Overall heat transfer coefficient A: Heat transfer area Here, from equations (2) and (3), the conversion rate per unit time, that is, the conversion rate is determined.

γ={1/(ΔH・W _R )} ・{C _PC・W _C・(T _OUT −T _IN ) +C _pn・W _T・(dT _R /dt)} ...(4).

The conversion rate calculated by the above calculation is
As shown in FIG. 3, the conversion rate is displayed on the display device 12 so that it can be seen where the conversion rate is in the stable zone, warning zone, or unstable zone determined in advance based on the design and control results. 103 process in the figure).

In the same way as the conversion rate is displayed on the CRT display device 12, the reaction trajectory centering on the internal temperature and jacket temperature of the reactor 1 is displayed on the CRT display device 12, and as shown in FIG. 4, the design and control results are displayed. It is displayed so that you can see where it is in the stable zone, warning zone, or unstable zone of the reaction trajectory determined in advance from etc. (Second
104 process in the figure).

Based on the above display results on the CRT display device 12, the stability of the reaction state is determined, and it is diagnosed whether or not there is an abnormality in the reaction process of the reactor 1 (step 105 in FIG. 2). Third
In the case of a reaction that shows curve A in the figures and FIG. 4, the conversion rate and reaction trajectory are stable, and it can be diagnosed that there is no abnormality in the reaction process. On the other hand, in the case of a reaction that shows curve B, the conversion rate and reaction trajectory are unstable, and it can be diagnosed that there is an abnormality in the reaction process.

Therefore, in this case, the temperature control cooling water flow control valve 5 is automatically or manually adjusted to raise or lower the jacket temperature, thereby controlling the temperature to return to a stable reaction state.

The display pattern on the CRT display device 12 may also be a pattern showing the progress of changes in the internal temperature of the reactor and the jacket temperature, as shown in FIG.

As described above, according to the abnormality diagnosis method of this embodiment,
Since the conversion rate of the raw materials is predicted using a reaction model and abnormalities in the reaction process are diagnosed from the predicted results, changes in the physical properties of the reaction products can be detected during the reaction and countermeasures can be taken early. Therefore, it is possible to prevent the generation of non-standard products, and this method is highly effective in batch reactors where once a non-standard product is generated, there is a risk that the entire amount cannot be used.

In addition, the conversion rate and reactor temperature are displayed on the CRT.
It is also possible to display the information on an indicator or recorder other than the display device. In this case, the stable zone and unstable zone can also be displayed on the scale of these meters or on recording paper.

[Effects of the Invention] As described above, according to the present invention, changes in physical properties of products can be detected early even in batch reactors, which have significantly more monitoring items and confirmation items than other processes. , it is possible to prevent the occurrence of substandard products.

[Brief explanation of the drawing]

1 to 5 are drawings relating to an embodiment of the method of the present invention, in which FIG. 1 is a block diagram of an implementation apparatus, FIG. 2 is a flowchart of the embodiment, FIG. 3 is a diagram showing the conversion rate, and FIG. The figure shows a diagram of the reaction trajectory centering on the internal temperature of the reactor and the jacket temperature, and FIG. 5 shows a diagram of the temperature change in the reactor. 1: batch reactor, 2: jacket, 3: cooling medium supply pipe, 4: heat exchanger, 5: control valve,
6: Cooling water supply pipe, 7, 8, 9, 10: Temperature detector, 11: Estimation calculation device, 12: CRT display device.

Claims (1)

[Claims] 1. In the batch reactor, at least one of the measured temperatures of the reactor internal temperature, jacket temperature, cooling water heat exchanger inlet temperature, and cooling water heat exchanger outlet temperature is used in the heat removal rate calculation formula and the conversion rate estimation calculation formula. The conversion rate is estimated by substitution, and abnormality diagnosis is performed by determining on a display device whether the estimated result is in a stable zone, warning zone, or unstable zone of the conversion rate determined in advance. A method for diagnosing abnormalities in batch reactors.