SU804641A1 - Method of emulsion polymerization process control - Google Patents

Description

54) METHOD FOR REGULATING THE PROCESS OF EMULSION POLYMERIZATION

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This invention relates to the automation of polymerization processes and can be used in the production of synthetic rubber.

There is a method of regulating the emulsion polymerization process, which consists in stabilizing the value of the ratio of hydrocarbon charge and emulsifier consumption by affecting the emulsifier consumption depending on the change in the polymerization rate determined in the group of polymerization units 1.

A disadvantage of the known method of controlling the polymerization process is that its implementation does not take into account changes in the surface tension of the latex. This indicator significantly affects the work of the subsequent stages of rubber production (distilling of unreacted monomers and mixing the latex with oil). In particular, it has been found that the duration of the distillation unit of unreacted monomers (distillation columns) and the degree of growth of these columns with polystyrene depend on the size of the surface tension of the latex. Particles of polystyrene, which are very fragile polymer, are placed in latex, are subsequently transferred to a rubber band and sharply deteriorate the mechanical properties of the latter. In addition, the uniformity of the subsequent mixing of rubber with oil depends on the magnitude of the surface tension, which also reflects on the quality of the finished product, in particular on the physical and mechanical properties of rubber.

The purpose of the invention is to increase the strength of rubber.

The goal is achieved by the fact that according to the method of regulating the emulsion polymerization process, consisting in stabilizing the value of the ratio of hydrocarbon charge and emulsifier consumption by affecting the flow rate of the emulsifier depending on the pt change of the polymerization rate, is determined by the polymerization rate, depending on the value of surface nat latex on the output of the group polymerization.

Claims (2)

In this case, the rate of polymerization is determined by the product of the flow rate of the reaction mixture by the difference in the value of the conversion of monomers at the output of the group of polymerization agents and at the output of the first polymerization agent. The method can be implemented using an automatic control system, a block diagram of which is shown in the drawing. j The system of automatic regulation by the polymerization process includes a battery consisting of regiments of gauges 1, 2 and 3, into which the pipeline 4 supplies the hydrocarbon to the charge, and the pipeline 5 emulsifier. Latex through pipeline b enters the latex degassing section. The flow rate of the hydrocarbon charge is measured and stabilized by the sensing element 7 / regulator 8 and the actuator 9. The sensing element 10, the regulator 11 and the actuator 42 form a loop for controlling the flow rate of the emulsifier. The current conversion value at the input of the second and at the output of the third polymerizer of the battery, respectively, is measured with analyzers 13 and 14. System. Auth: Mmatichvskogo regulation of contents. A computing device 15 is installed which determines the rate of polymerization. At the input of the computing device 15, signals from the sensing element 16, with which the flow rate of the reaction mass is measured, and signals from the analyzers 13 and 14, measuring the current value of the monomer version are received. Computing device 15 functions as follows. First, the residence time of the reaction mixture in polymerization agents is determined by the following formula, where V is the volume of polymerization agents into which the conversion of monomers is determined; V (.second volume flow rate of the reaction mixture. Next, the computing device calculates the polymerization rate using the formula Ca - C where C 2 and the conversion of monomers at the output of the third and the input of the second polymerizer. The output signal of the computing device 15, proportional to the current polymerization rate, to the controller 17, where it is compared with a signal proportional to a given value of the polymerization rate. The controller 19 receives signals from the analyzer 18 and the setting device 20, which are proportional to The current value of the latex surface tension and its predetermined value. The error signal of the latex surface tension regulator 19, proportional to the deviation of the latex surface tension from its predetermined value, enters the polymerization rate regulator 17. The signal from the regulator 17 enters the chamber setting the ratio controller 11. The output signal of the ratio mountain 11 is fed to the controller (additional mechanism 12 installed on the emulsifier pipe. At the entrance to the battery of polymerizers 1, 2, and 3, the ratio of the hydrocarbon charge to the emulsifier is corrected with an impact on the flow rate of the emulsifier. Depending on the deviation of the current value of the Latex surface tension from its polymerization rate set on the regulator 17, a correction signal is received from the regulator 19. The polymerization rate regulator 17 produces a ratio to the regulator 11, which corrects the ratio of the hydrocarbon blend and the emulsifier with the effect on the consumption of emulsifier. The result of the implementation of the method is the maintenance of a predetermined surface tension of the latex, which helps to increase the strength of the finished rubber. A preliminary calculation shows that, from the implementation of the proposed control method in the production of average power, the tensile strength of rubber can increase to 250 kg / cm against 240, and its cost can be reduced by 0.5%. Claim 1. The method of controlling the emulsion polymerization process, which consists in stabilizing the value of the ratio of hydrocarbon charge and emulsifier consumption by affecting the flow rate of the emulsifier depending on the change in the polymerization rate, which is determined in order to increase the strength of rubber, the magnitude of the rate of polymerization, depending on the magnitude of the surface tension of the latex at the exit of the group of polymerizers. 2. A method according to claim 1, characterized in that the polymerization rate is determined from the product of the flow rate of the reaction mixture by the difference in the conversion of monomers at the output of the group of polymerization units and at the output of the first polymerizer. Sources of information taken into account during the examination 1. O. Litvin The basics of rubber synthesis technology. N .; Chemistry, 1964, p. 366-386.