SU954395A1 - Method for controlling process of emulsion polymerization in the production of butadiene-styrene rubber - Google Patents

Description

In this case, the conversion of monomers at the outlet of the polymer battery can be adjusted by changing the insertion point of the stopper and its consumption.

The drawing shows the implementation of the method.

The diagram shows: polymers 1 and 2 batteries, pipelines 3 emulsions, monomer 4 (due to comparable reactivity styrene and butadiene are considered as one monomer), modifier 5, latex 6, stopper 7 to 9, sensitive elements 10 (emulsion consumption) monomer 11 and modifier 12, analyzer 13 of monomer conversion at the output of the last polymerizer, regulator 14 of monomer conversion, analyzer 15 of the average molecular weight of the polymer, switch 16, sensitive element 17 of the stopper consumption at the spring of the last polymerizer , the stopper flow controller 18 at the output of the last polymerizer, the regulator 19 on the line of the stopper supplied to the last polymerizer, the sensitive element 20 of the stopper flow supplied to the input of the last polymerizer, the regulator 21 of the stopper flow at the entrance of the last polymerizer, regulator 22 on the pipeline the supply of the stopper to the input of the last polymerizer, the analyzer 23 of the conversion of monomers at the input of the last polymerizer, the analyzer 24 concentrations of mo. DIFFER AND COMPUTER BLOCK 25.

The method is carried out as follows. in a way.

At the input of polymerization unit 1 (the polymerization battery in the diagram is conventionally shown by two polymerization units 1 and 2), an emulsion consisting of monomers, a modifier, an activator, an initiator and an aqueous phase (the activator, initiator and water phase are not shown according to the diagram) is fed through pipeline 3 Latex is transported via pipeline b of the short-circuit of the polymerization shop to the non-polymerized monomer unit. To prevent the polymerization reaction, a stopper is fed through line 7. Depending on the value of the monomer conversion, it is passed either through conduit 8 to the main of the last polymerization unit of the battery, or via conduit 9 to the output of the polymerization battery.

Emulsion costs; the monomers and modifier are modified by the sensing elements 10-12.

The amount of monomer conversion at the outlet and the inlet of the last polymerizer of the battery is measured by analyzers 13 and 23, respectively.

Signal proportional to the current monomer conversion value

at the outlet of the polymer battery, fed to conversion controller 14. In the camera task controller 14 receives a signal from the analyzer 15, is proportional to the value-average

polymer molecular weight.

The sensing element 17, the regulator 18 and the regulator 19 form a circuit regulating the flow of the stopper supplied to the output

polymerization battery. The sensing element 20, the regulator 21 and the regulator 22 form a circuit for controlling the flow rate of the stopper supplied to the input of the last polymerizer of the battery. The concentration of the modifier at the output of the first polymerizer is measured by the analyzer 24. The control system contains a computing unit 25, to the input of which

Sensors 10-13, 23JH 24 are connected that measure the current values of emulsion, monomer, modifier, and monomer conversion rates at the inlet and outlet of the last polymerizer bata and the concentration of modifier at the output of the first polymerizer battery.

Initially, the computing unit calculates the residence time of the reaction mixture in the polymerizer 1 as the ratio of the volume of the given battery polymerizer V to the emulsion consumption G e

g- v-,

 -G;

Next, the computational unit determines the rate of consumption of the monomers W and the modifier W using the following equations: с С g

- with

U Ohm.sh -Ci

See 4J Ga w, 1

where g

monomer charge

1Ч.Ш at the entrance of polymerization unit 1;

GM with. Judicial expenditure; the amount of monomer conversion at the output of the first polymerizer of the battery;

The concentration of the initial modifier (set); C modifier concentration at polymerization outlet 1

Computing unit 25 finds the relative values, compares the values found with the nominal values and, depending on the deviation value, determines the set value of monomer conversion at the output of the polymerizer battery, the original signal of the computational unit 25 enters the correction chamber of the regulator 14. Stop meter consumption that follows to provide, by changing the reference, the flow regulator 18 and 21, is calculated as follows.

First, the total number of stoppers to be supplied to the battery is determined.

t MW

where K is the expenditure ratio of the stopper, showing the amount of stopper that the KA unit of weight of the formed polymer needs to be applied to;

Cn conversion, achieved at the exit of the battery. Next, calculate the proportion of the increase in conversion in the last polymerization of the battery (according to the schemes, e in polymerization unit 2 by the expression

yp

WITH

Then determine the stopper flow rate that the regulator 21 should provide.

TO-,-

GC., Dp and controller 18

 GC

The connection of the corresponding regulator is carried out with the help of the switch;

Thus, along with a change in the set value of monomer conversion at the output of the polymer battery, depending on the average molecular weight of the polymer, the system performs an additional adjustment to the set value of the monomer conversion depending on the ratio of the monomer consumption rate to the value of the flow rate modifier defined in one or several consecutively arranged along the course of the reaction mixture polymerizeroos. With an increase in the value of this ratio against the nominal value, the specified value of monomer conversion and vice versa is reduced, and the monomer conversion value at the output of the polymerisation battery is controlled by changing the insertion point of the stopper and its consumption.

The result of the implementation of the proposed method will be a decrease in the mean square deviation of the elasticity of rubber by rebound to 2 units (the known method gives 6-8 units). This in turn will allow to obtain a large economic effect in the national economy.

countries by increasing the service life of rubber products made from this product.

Claims (2)

1. A method of controlling the process of emulsion polymerization in the production of styrene-butadiene rubber carried out in a battery of sequentially installed polymerizers, which consists in changing the set value of the conversion of monomers depending on the average molecular weight of the polymer, characterized in that, in order to improve the accuracy of stabilization rebound rubber elasticities 25 corrects the measured value of the conversion of monomers at the outlet of the polymer battery in inversely proportional to the ratio of the rate of consumption of monomer to , - modifier consumption rate,  defined in one or more sequentially along the reaction mixture polymerizers 2. The method according to claim 1, characterized in that the conversion of the monomers at the outlet of the polymer battery is controlled by changing the insertion point of the stopper and its consumption. Sources of information 40 taken into account in the examination 1. Technological regulations Sumgait synthetic rubber plant. Production of synthetic rubber. Sumgait, 1975, p.33. 45 2. USSR author's certificate  401976, cl. G 05 D 21/00, 1969 (prototype).