SU749422A1 - Method of controlling complex-catalyst components ratio - Google Patents

Description

The invention relates to the field of controlling the ratio of catalyst components during its preparation and can be used, in particular, to control the ratio of catalyst components to the polymerization of isoprene. The known method of determining the equimolar ratio of the components of a complex catalyst by the minimum value of the dielectric constant of the reaction mixture 1. A disadvantage of the known method is the low dynamic accuracy of stabilizing the ratio of catalyst components associated with the inertia of finding the minimum of dielectric constant, since the control effect is directed to a change in concentration over the entire reaction volume. A method of regulation is known, an exothermic reaction by stabilizing the stoichiometric ratio of the components by changing the flow of one of the components to the pre-mixing zone to reduce the temperature temperature in the mixer, to which the flow of the missing component is fed, to a value close to zero 2. The disadvantage of this method is that when one of the flows supplied to the premixing zone / the required static accuracy of stabilizing the ratio of components cannot be achieved. The closest in technical essence to the invention is a method of controlling the ratio of the components of a complex catalyst in its preparation by mixing components with a deliberate disadvantage between the differential sensors of the physical parameter of the katashizatr (dielectric constant) associated with the extremal dependence on the ratio of the components and by changing the flow rate of the component supplied by the change in the difference between the indications of differential probes and ampli- tudes 3. The disadvantage is that Nogo method is the low accuracy .stat11cheska stabilization ratios komponentov.i, since the method provides for control of the zero value of the difference readings differential sensors.

It has been established that the accuracy of stabilization of a given value of the ratio of components (corresponding to the minimum of the visy or maximum dependence of the physical parameter on the ratio of the catalyst component components) increases if the process is controlled by a non-zero differential spacing {gi / a at zero or close to zero difference increment differential sensor readings. The purpose of the invention is to increase the accuracy of stabilization of a given value of the ratio of its components.

The goal is achieved by increasing the consumption of the additionally supplied missing component; at the beginning of the preparation of the catalyst. from zero to the value at which the increment of the difference in the readings of the differential sensors reaches the minimum target or zero value.

At the same time, the specified value of the maximum difference in the readings of the differential sensors or the specified flow rate of the additionally supplied missing component of the catalyst is stabilized by varying the flow of one of the components supplied to the mixing zone of the catalyst components.

As a controlled physical parameter of the catalyst, the temperature or optical density of the reaction mixture is used.

FIG. 1 shows typical graphs of the dependence of the physical parameter F on the ratio of the components A / B; in fig. 2 is a block diagram of a system controlling the ratio of components of a complex catalyst.

From the graphs it can be seen that in order to accurately achieve a given value of the ratio, one should first mix the components with some disadvantage of one of them (point 1), and then add the missing component A until the difference F (C2) - F (CJL) reaches maximum value. Almost inertia-free search for this maximum difference in the indications of differential sensors by changing the flow rate of the component between the sensors is one of the features of this method.

Another feature is the following.

The bottoms of some catalysts are important not only with high accuracy of stabilization. zirovat this vernacular ratio of components in the final reaction products, but also pre-mix the components in a ratio as close as possible to the given, because otherwise

with an excess or deficiency of one of them, undesired side reactions take place in a number of cases. It follows that point 1 should be as close as possible to point 11. However, making the difference FCCj) F (Cj.) Almost close to zero is impossible because of the really limited sensitivity of the sensors or because of the technical difficulty of accurately metering the additionally missing component. whose consumption is very small. In this case, it is preferable to stabilize the specified value of the maximum difference between the readings of the differential sensors or the flow rate of the additionally missing component entered between the differential sensors, which can be achieved by changing the ratio of 1 and the flow rates of the components during the preliminary mixing process, for example, by changing the flow rate of one of the components, supplied to the premixed mixing zone.

The method is carried out as follows.

Components A and B are continuously fed through pipelines 1 and 2 to the premix reactor 3. The flow rates of the components are stabilized using local automatic control systems (ACP), consisting for component A of sensor 4, flow regulator 5 and valve 6, for component B - of sensor 7, flow regulator 8 and valve 9, for additionally supplied flow - from sensor 10, flow controller 11 and valve 12.

An additional flow of the missing component is introduced between the differential sensors 13 and 14, which measure the dielectric constant of the reaction mixture. The difference in the readings of the differential sensors is measured: by the device 15, the output of the device is connected to the experimental controller 16 and the logical functional device 17 (the sensor 10 of the flow rate can be similarly connected to the input of the device.

The control system operates as follows.

Claims (3)

9.5 l / min of component A and 10 l / min of component B with a concentration of 100 g / l are fed to the reactor 3, and the costs of the components are stabilized using local ACP. From the zero value, the consumption of the missing component, introduced between sensors 13 and 14, is increased, giving impulses to increase the flow rate from the extreme regulator 16 to the input of the flow regulator 11. The pulses are fed in increments of 0.01 l and at intervals of 15 s. The on-output signal of the device 15 begins to increase from zero to the maximum possible. At the same time, the increment of the signal of the device 15, calculated by the extreme regulator 16 at each step of increasing the consumption of the missing component, gradually decreases to a maximum value to a value close to zero. This is due to the transition from a steep section of extreme dependence to a flat section. Upon reaching the minimum specified or zero value of the signal increment from the device 15, the regulator 16 stops producing pulses to increase the flow rate to the controller 11. The logical functional device 17 goes into operation after stopping the changed signal of the device 15, and compares the maximum difference value sensor readings 13 and 14 (de) with a given. In the case of a deviation from the given value, the flow rate of component A is adjusted by changing the setting 5 using controller 17 (or analogs for component B - controller 8). All the control operations described above, after reaching the goal, the control is stopped, and the flow rate of the component A supplied between the sensors 13 is 0.5 l / min. When the concentration of one of the components changes, for example, when the concentration of components B is increased to a value of 120 g / l, the C / A ratio at the outlet of reactor 3 begins to decrease and the points Cj and Cg in graph 1 move to the left. The slope of the characteristic increases and the value of de increases, and the functional block 17 is activated, which increases the task to the controller 5 until the value of de returns to its original value. As a result, the consumption of component A, supplied for the preliminary mixing, will be 11.5 l / min. The accuracy of the stabilization of the ratio of the catalyst components using this control system determines with accuracy the operation of the extreme regulator and, in principle, is determined by the value of one step of changing the flow rate of component A supplied between sensors 13 and 14, i.e. a value of 0.01 liters, which is 0.1 ratios. It should be noted that the control operations envisaged by this method can be used both at the initial stage of the catalyst preparation process and during the whole process. To do this, it is necessary periodically (for example, 1 time per hour) to reduce the consumption of the additionally supplied component to zero or to any value (for example, 10-20% of the initial value) and then repeat all control operations. Thus, the proposed method allows to increase the accuracy of stabilization of the ratio of the catalyst components. As a result, the activity of the catalyst is increased, which makes it possible to reduce its specific consumption by 2.5%. The approximate annual effect of using this method for a plant with a capacity of 100 thousand tons of rubber per year will be 25 thousand rubles. 1. Method for controlling the ratio of components of a complex catalyst by mixing components with a deliberate disadvantage of one of the components, additionally introducing the missing component between the differential sensors of the physical parameter of the catalyst, monitoring the ratio of the extreme dependence of the physical parameter on the ratio of the components using differential sensors and measuring the flow rate of the additionally supplied differential difference component In order to improve the accuracy of stabilization of the catalyst components, the flow rate of the additionally supplied missing component is increased at the beginning of catalyst preparation from a zero value to a value at which the increment of the differential difference between the differential sensors reaches a minimum target value or zero, 2. The method Section 1, I distinguish it by the fact that they stabilize a given value of the maximum difference of differential readings: sensors or a given value ode additionally supplied missing catalyst component ratios change cost components fed into the mixing zone. 3. A method according to claim 1, characterized in that the temperature or optical density of the reaction is used as the controlled physical parameter of the catalyst. Sources of information / taken into account in the examination 1. USSR author's certificate. I 306766, class G 01 N 27/22, 1969. 2. USSR author's certificate 226559, cl. B 01 R 3/08, 1967. 3. USSR author's certificate 388660, cl. G 01, 27/00, 1971. F (() F (c f (Ci F (c) F (4l F (CS) Ci QS, ftfu.S. / Phi .z R.I.I.I.