RU171499U1 - DEVICE FOR POLYMERIZATION OF ISOPRENE IN MASS - Google Patents

Abstract

The claimed technical solution relates to the chemical industry, namely the production of polyisoprene. The technical result of the proposed solution is to develop a device design and technology for the synthesis of diene rubbers in the mass of monomers (in the absence of solvent), which simplify the process (as excluded from the process washing, isolating and drying the rubber), reducing its energy intensity, reducing the cost of rubber, increasing the environmental cleanliness of production. The mass for polymerization of isoprene contains an airtight container, inside which the initial components are placed, a heater for creating a temperature field, a thermocouple and a temperature regulator, and closed circuits consisting of containers with a monomer and catalytic complex, pipelines, pressure regulators are placed in the container in an inert medium , pumps, a gear pump is installed in each individual circuit to circulate the monomer and the catalytic complex in its circuit until the necessary calculation is achieved temperature fixed by sensors placed in front of the nozzle-injector, each circuit is equipped with a three-way valve for filling and draining components into a storage tank, each circuit is equipped with a nozzle-nozzle located on the pipeline between the pump and the pressure regulator, metering nozzles are made with a slit-like the nozzle, which forms a torch in the form of a plane for the injection of components into the polymerization cell, the axis of the dispenser nozzles are placed at an angle that ensures the intersection of the injection planes in a straight line inii, each circuit is equipped with a controller with relays, providing cyclical injection in accordance with programmoy.Zayavlyaemoe solution can significantly reduce the capital cost of the equipment and production facilities, as well as to reduce the current costs of production and to reduce harmful effects on the ecology of the region, where production is located.

Description

The claimed technical solution relates to the chemical industry, namely the production of polyisoprene.

In the isoprene polymerization processes, the most energy-intensive and apparatus-intensive stages are solvent distillation plants - isopentane and toluene (distillation columns), degassers (apparatus 100 m in volume, filled with water at a temperature of 100 ° C, condensers, cooling towers, electric motors, measuring and measuring equipment ( Instrumentation), pipelines, pumps.When carrying out the process of polymerization of isoprene in bulk, i.e. in the absence of solvent, all the following stages are excluded from the technological scheme: washing the polymer, isolating the polymer and, drying the polymer, which significantly reduces the metal content and energy process.

A technical solution is known according to patent RU No. 2563844 dated 06.27.2014, MKI C08F 136/08 Method for the polymerization of isoprene in bulk in low-volume cells, comprising introducing a catalyst system operating in the presence of isoprene, where a system based on at least one is used as a catalyst system a conjugated diene monomer, one salt of one or more rare earth metals of organic phosphoric acid, one alkylating agent of the formula AlR ₃ or AlR ₂ Hal and one halogen donor, which is a halide alkyl aluminum. polymerization of isoprene,

on a conveyor belt in which cells having the shape of a hemisphere are made, a polyethylene film 1-10 μm thick is applied,

the conveyor belt together with the film is heated to a temperature of 80-120 ° C, as a result of which the polyethylene film acquires a flow property and exactly repeats the shape of the cell of the conveyor belt,

the conveyor belt is cooled together with the adjacent polyethylene film by blowing with cold inert gas: argon, nitrogen, to better distribute the substance of the catalytic system in the monomer mass and to prevent the polymerisation reaction from starting prematurely, they mix the catalytic system and monomer in the mixer, in the temperature range from - 80 to -50 ° C in a ratio of 1/40000 to 1/200000 mol / mol with accurate keeping the ratio of components;

the finished mixture of the monomer and the catalytic system is packaged with a dispenser into polymerization cells with a volume of from 0.01 to 1 dm ³ , without subsequent mixing of the mixture, at overpressure to suppress boiling (foaming) of the monomer, in an inert gas environment selected from the group: helium , argon, nitrogen at a temperature of -80 - -50 ° С,

the polymerization process is carried out in the mass of monomer in each individual cell at an elevated pressure of 1-10 atm and a temperature from -50 to + 100 ° C for 90-5 minutes, the cells are sealed with a microperforated plastic film, the cells are evacuated to distill out the remaining non-polymerized monomer for 10-600 sec,

supplying a modifying agent selected from the group: chlorine, bromine, supplying an antioxidant to each cell,

remove the finished cells with the polymer from the conveyor and separate the cells with the polymer on a drum with a corrugated surface to form individual granules.

The disadvantage of the technical solution is the heterogeneity of the distribution of the catalytic complex in the mass of monomer, as a result of which the volume of unpolymerized product increases at the output.

Known technical solution according to patent No. 20060043556.4., RU 2395528 dated 04/11/2006, CN, relating to a method for the synthesis of polyisoprene characterized by a high content of trans-1,4 units, where block precipitation polymerization of isoprene is used, catalyzed by a supported titanium catalyst TiCl ₄ / MgCl ₂ which comprises the steps of prepolymerization, polymerization, drying and degassing, carried out in the prepolymerization reactor equipped with an anchor agitator, a polymerization reactor equipped with a stirrer ribbon intovoy blade, scraper and vacuum dryer.

The disadvantage of the devices used in the synthesis of trans-1,4 polyisoprene is a decrease in the equipment's operability due to the sticking of rubber in the prepolymer.

As a close analogue, the technical solution according to patent RU No. 2444529 from 2010-07-13, IPC C08F 2/01, C08F 2/02 was selected. C08G 59/00. The device for directed polymerization contains a sealed container, inside which a mixture of the starting components is placed, a multi-section heater for creating a gradient temperature field, a device for moving the container parallel to the axis of the multi-section heater, a thermocouple and a temperature regulator.

The advantage of the device is the ability to obtain polymers having a monomolecular structure, which determines the increased mechanical strength and thermal stability of the polymers.

The disadvantage of this device is an unregulated ratio of components, leading to heterogeneity of the distribution of the catalyst in the monomer and reduced conversion.

The technical result of the proposed solution is to develop a device design and technology for the synthesis of diene rubbers in the mass of monomers (in the absence of solvent), which simplify the process (since the stages of washing, isolating and drying rubber are excluded from the process), reducing its energy consumption, reducing the cost of rubber, improving the environmental cleanliness of production.

The goal is achieved as follows.

The device for the polymerization of isoprene in bulk contains an airtight container, inside which the initial components are placed, a heater to create a temperature field, a thermocouple and a temperature controller,

in a container in an inert environment placed closed circulation circuits consisting of tanks with a monomer and a catalytic complex, pipelines, pressure regulators, pumps,

in each separate circuit there is a gear pump for circulating the monomer and the catalytic complex in its circuit until the required calculated temperature is recorded by sensors placed in front of the nozzle-nozzle, each circuit is equipped with a three-way valve for refueling and draining the components into a storage tank,

each circuit is equipped with a metering nozzle located on the pipeline between the pump and the pressure regulator,

dispenser nozzles are made with a slit-like nozzle, which forms a torch in the form of a plane for the injection of components into the polymerization cell,

the axis of the dispenser nozzles are placed at an angle that ensures the intersection of the injection planes in a straight line,

each circuit is equipped with a controller with a relay, which ensures the injection cycle in accordance with the program.

In the drawing of FIG. 1 is a general diagram of a device,

 ude 1 - a container for storing monomer with an inert gas supply and circulation device;

2 - capacity for storage of the catalytic complex;

3 - pressure regulators in front of the dispenser nozzle;

4 - thermocouples determine the current temperature of the monomer and the catalytic complex in the circuit;

5 - electronically controlled metering nozzles for precise dosage of the amount of monomer and catalyst complex;

6 - heat exchangers for controlling the temperature of the monomer and the catalytic complex;

7 - cell for the polymerization of the product;

8 - gear pumps to ensure the circulation of the monomer and the catalytic complex in a closed loop;

9 - connecting hoses made of polyurethane;

10 - return three-way valve for feeding the monomer and catalytic complex back to the storage tank;

11 - relay;

12 - controller.

The essence of the technical solution is as follows.

The initial components are placed in an airtight container with dry argon: in a container for storing monomer 1, in a container for storing catalytic complex 2.

At the inlet pipe 9 of each tank there is a three-way return valve 10 for supplying the components back to the storage tank.

A gear pump 8 is installed on the outlet pipe 9 of each tank to ensure the circulation of components in a closed loop.

A heat exchanger 6 is installed at the inlet pipe 9 of each tank to control the temperature of the components.

At the inlet pipe 9 of each tank, a pressure regulator 3 is installed in front of the dispenser-nozzle 5.

In front of the dispensing nozzle 5, a thermocouple 4 is installed to determine the current value of the temperature of the components in each circuit when supplied to the polymerization cell 7.

In front of the dispenser-nozzle 5, a relay 11 is installed, connected to the controller 12. The device operates as follows /

The circulation loop is preliminarily cleaned and filled with pure and dry argon, and they are charged alternately in separate containers 1.2 prepared for polymerization of the monomer and catalytic complex. Refueling is carried out in an inert gas environment to prevent contact of the prepared components with the environment containing impurities - catalytic poisons. With the help of circulation gear pumps 8, the monomer and the catalytic complex of tanks 1.2 are fed through polyurethane connection hoses 9 to the circulation circuits, where they pass through the pumps 8 themselves, metering nozzles 5, pressure regulators 3, heat exchangers 6 and go to the point return in tanks 1, 2 for storage of monomer and catalytic complex. Before entering the containers 1.2 for storing the monomer and the catalytic complex, three-way valves 10 are located to drain the first portion of the component that has passed through all the technological elements of the circulation circuit and contains residual impurities.

After draining the first “dirty” portion of the monomer and the catalytic complex, the three-way valves 10 switch to drain the components in the storage tank, and the components begin to circulate in a closed loop. With constant circulation of the components, the temperature of the monomer and the catalytic complex is adjusted to the calculated value using heat exchangers 6. The temperature of the monomer and catalytic complex can vary from -80 to + 80 ° С. The temperature of the monomer and the catalytic complex in the loop is controlled by an electronic thermocouple 4, which is located in the immediate vicinity of the nozzle-nozzle 5, and shows the temperature of the component when it is fed into the polymerization cell 7.

The dosage of the components in the polymerization cell 7 is carried out using a dispenser-nozzle system 5 with adjustable spray parameters of very small amounts of liquid in a ratio of 100: 1 to 160: 1 (monomer: catalytic complex). The exact ratio of the components when they are mixed and fed into the polymerization cell (reactor) is achieved by modulating the width of the electric pulse, which opens the metering nozzles 5, which feed the monomer and the solution of the catalytic complex for predetermined periods of time, and by adjusting the pressure in the supply lines of the monomer and catalytic complex . Dispensers nozzles 5 are made with a slot nozzle providing a planar shape of the injection torch.

The location of the axis of the nozzles at an angle that ensures the intersection of the planes of the torches of the monomer and the catalytic complex in a straight line, ensures their effective mixing and allows the polymerization process to be carried out with a higher speed and greater conversion to obtain a higher quality product.

After holding the mixture of components in the polymerization cell for 2 minutes, the cell with the polymer is subjected to vacuum until the monomer is completely removed from the polymer, after which an antioxidant is injected into the cell under pressure in a dosage of 2.0% wt. on the polymer.

After filling the polymer with an antioxidant, the cell with the finished product is moved to the finished product warehouse.

The studies were carried out as follows. The process was controlled by adjusting the components of the valve terminal, which send signals to solid-state semiconductor relays, and those, in turn, open the supply of a working voltage of 12V directly to the solenoid valve of the metering nozzle.

The adjustment of the ratio of the components was achieved with an accuracy of 100: 1, vol. (shown in Table 1).

The ratio of the monomer and the catalytic complex was adjusted by creating the necessary pressure in the supply lines of the monomer and the catalytic complex, as well as by selecting the duration of the working cycle of the nozzle-dispenser of the catalytic complex. In this case, the monomer in all experiments was supplied with a constant (continuous) flow, and the feed of the catalytic complex was evenly distributed over the entire time interval of the monomer supply with short-term operating cycles for opening the electromagnetic valve of the nozzle-dispenser for feeding the catalytic complex.

Example.

When the monomer is continuously fed for 5 seconds, the catalytic complex is fed 50 times periodically with the valve opening intervals of the catalytic complex nozzle-dispenser equal to 0.01 sec. Thus, at the same pressure in the supply lines of the monomer and the catalytic complex, the ratio of the components was 100: 1. When the pressure in the highways changed, the ratio could be brought up to 200: 1.

The mode of supply of the antioxidant to the small cell after the completion of the polymerization process was selected continuous. The antioxidant was injected from a dispensing nozzle creating a torch shape in the form of a cloud, which ensured uniform distribution of the antioxidant to the finished polymer. In the software, a parameter was selected that is responsible for the time span of finding a low-volume cell in the polymerization zone, and it is possible to quickly change it to select the polymerization time (shown in Table 2).

Currently, the production of cis-1,4-polyisoprene at the Nizhnekamsk production association Nizhnekamskneftekhim uses equipment occupying large production areas, consuming huge energy and natural resources, while the environmental situation is suffering, while the proposed technical solution allows to reduce the above costs, namely, from the production process chain are excluded:

Metal and energy-intensive equipment, the use of a large amount of water resources:

- site of small mixers for mixing isopentane with isoprene;

- assembly of high-speed, low-volume viscous polymerizate mixers with a solution of antioxidant (AO) in toluene in methanol for deactivation of the catalytic complex (CC) and AO refueling;

- AO preparation unit with receiving tanks for toluene, methanol and AO and for their mixing for the preparation of AO solution;

- a number of low-volume polymerizate mixers with softened water for water washing from catalyst residues after hydrolysis;

- for the preparation of the anti-agglomerator - the department for the preparation of calcium stearate, an agent that prevents the adhesion of rubber crumbs at the stage of water degassing in the averagers;

- water degassers for distillation of organics (isopentane, toluene, methanol) from rubber at a temperature of + 100 ° C (steam); crumb formers;

Expensive equipment:

- polymer concentrators, expellers and extruders;

- a number of settling and distillation apparatuses for separating water and organics and their subsequent distillation on distillation columns to return to the technological cycle;

- a number of distillation columns for evaporation, purification and distillation of the monomer and isopentane returned to the process.

The claimed solution can significantly reduce capital costs for equipment and production facilities, as well as reduce current costs for production and reduce the harmful effects on the environment of the region where the production is located.

Claims (12)

A device for the polymerization of isoprene in bulk, containing a sealed container inside which the original components are placed, a heater to create a temperature field, thermocouple and temperature controller, characterized in that in a container in an inert environment placed closed circulation circuits consisting of tanks with a monomer and a catalytic complex, pipelines, pressure regulators, pumps, in each separate circuit there is a gear pump for circulating the monomer and the catalytic complex in its circuit until the required calculated temperature value is recorded by the sensors placed in front of the nozzle-nozzle, each circuit is equipped with a three-way valve for refueling and draining components into a storage tank, each circuit is equipped with a metering nozzle located on the pipeline between the pump and the pressure regulator, dispenser nozzles are made with a slit-like nozzle, which forms a torch in the form of a plane for the injection of components into the polymerization cell, the axis of the dispenser nozzles are placed at an angle that ensures the intersection of the injection planes in a straight line, each circuit is equipped with a controller with a relay, which ensures the injection cycle in accordance with the program.

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