SU596597A1 - Method of automatic control of semicontinuous process of polymer production - Google Patents

Description

(54) AUTOMATIC CONTROL METHOD FOR SEMI-INTERRUPTED POLYMER PROCESS

the masses in the reactor and the value of the volume of the initial reactants in the reactor and depending on the value of the indicated ratio change the flow rate of the additional reactants into the reactor.

The drawing shows a block diagram of the automatic control system explaining the proposed method.

The automatic reactor control system 1. contains a viscosity sensor 2 with a measuring device 3 and a viscosity regulator 4, a level sensor with a measuring device b and a level 7 regulator, a ratio controller 8, a flow controller 9, a measuring device 10, a flow sensor 11 and valve 12.

PRI me R. The proposed automatic control method was tested in a stirred reactor during the synthesis of polyurethane for synthetic leathers. The following instruments were used:

viscosity sensor 2 - rotary industrial submersible viscometer type RPP-1;

measuring device 3 - secondary devices such as KSP-3 and PV 10.1E;

viscosity regulator 4 - proportional pneumatic regulator of the type PR 2.5;

Level 5 sensor - DM-P2 type manometer;

measuring devices b and 10 secondary devices of type PV 10.1E;

the level controller 7 is a proportional pneumatic controller of the type PR2.5; :

regulator of ratio 8 - pneumatic regulator of the type PR3.24;

flow regulator 9 - pneumatic controller type PR3. ,; flow sensor 11 - RPM-O type rotameter;

 valve 12. - pneumatic adjustable valve type PKN-DUB.

Prior to starting the supply of additional reagent, which causes an increase in the viscosity of the reaction mass as it is supplied, a solution of the starting reagent — low molecular weight polyurethane — is prepared in the reactor, then a solution of the additional reagent of diisocyanate is continuously fed until a given viscosity of polyurethane is obtained, for example, 600-25 p.

The viscosity value of the reaction mass in reactor 1 is measured by viscosity sensor 2 with measuring device 3, the received signal is fed to the input of viscosity regulator 4, where it is compared with a given final value. The volume of the reaction mass in the reactor is measured by a level sensor 5c with a measuring device 6, the received signal is fed to the input of a Level 7 controller, where

it is compared with the initial value of the reaction mass level in the reactor, which is set as a reference to the level controller 7. The output signal from the level controller 7 is fed as a correction signal to the ratio controller 8. The output of the viscosity regulator is fed to the atoro input of the regulator 4, the input of the regulator 8 is connected to its output, and the output signal from the regulator 8 is fed as a correction to the flow controller 9. The input from the flow regulator 9 receives a signal from the measuring device 10 connected to the flow sensor 11. The output A signal from the flow regulator 9 is fed to the valve 12 installed on the supply line of the reactants to the reactor 1,

At the beginning of the process, the magnitude of the viscosity deviation from the set end value is large, and the increment of the reaction mass volume (level) is small — the maximum signal is generated at the output of the ratio controller 8, which results in the valve 12 being fully open. Due to the supply of reagents, the volume of the reaction mass (level) increases, and the viscosity due to delay changes very little. The output signal of the ratio controller 8 decreases due to an increase in the signal from the level regulator 7. With this regulator 8 switching on circuit, its output signal is proportional to the ratio of the amount of viscosity deviation from the set value to the increment of the reaction mass the mass of the ratio regulator signal 8 decreases more and more, however, the complete cessation of the supply of reagents is possible only when the specified viscosity value is reached, when the output signal of the regulator is reduced to a minimum smooth and 7, respectively, were schiys with it in the output ratio regulator 8.

Thus, the consumption of reagents as the reactor is filled and the viscosity value approaches the specified value will be reduced to a minimum.

The proposed method makes it possible to increase the accuracy of the stabilization of product quality due to a more accurate achievement of a given viscosity value.

Claims (1)

1. USSR author's certificate I 465215, cl. At 01 J 1/00, 1973. . tt