High density polyethylene (1967)

Industrial landscape at night.

Chemical laboratory.

Experiment to determine the properties of polyethylene.

Polyethylene products do not sink in water, because this polymer is lighter than water.

Polyethylene does not absorb water.

Polyethylene is resistant to strong acids.

Polyethylene sheets were placed in vessels with sulfuric and hydrochloric acid and placed in a thermostat at a temperature of +80 degrees.

After several days, we see that the sheets have not been destroyed.

Experiment on the effect of low temperatures on polyethylene.

Let's place a polyethylene sheet in a vessel with dry ice in alcohol, where the temperature is 70 degrees below zero.

The sheet did not become brittle after exposure to low temperatures.

This property makes it possible to use polyethylene products in areas with a harsh climate.

A transparent polyethylene film comes out of the extruder head.

It melts relatively easily when heated and acquires amazing plasticity, which allows it to be given any shape.

Exterior of a polyethylene production plant.

Torches for burning waste from oil refineries.

Now, the most valuable compounds ethylene and propylene are obtained from these wastes.

When processing these compounds, it is possible to obtain polyethylene, ethylbenzene, styrene and various alcohols, phenol, acetone and many other chemical products.

Equipment for obtaining polyethylene.

There are three main methods for obtaining polyethylene at high, low and medium pressure.

Panorama of the polyethylene production plant.

Gas fractionation unit, where the narrowest fractions, including ethane and hexane, are selected from wide fractions of petroleum feedstock.

The hydrocarbons separated here are sent to collectors, and then through pipelines to the central raw material warehouse or directly to the pyrolysis units of the chemical plant.

Control panel for automated processes of chemical production.

Hydrocarbon raw materials are fed into the pyrolysis furnaces.

In the furnace pipes, the raw materials are heated to a temperature of 780-840 degrees, depending on the composition of the gases.

The red-hot walls of the furnace transfer heat to the radiant pipes through which the gas passes.

Under the influence of high temperature the process of pyrolysis takes place as a result of which hydrogen, methane, ethylene, propylene, butylenes, aromatic and other hydrocarbons are formed.

When leaving the furnace the pyrolysis gases are sharply cooled with water to stop the reaction.

Then they are washed with water in a scrubber and in a foam apparatus.

After passing the heat exchanger, the gases freed from heavy aromatic hydrocarbons are sucked in by compressors.

Here the pyrolysis gases are compressed to 40 atmospheres and after the refrigerator and oil separator are sent to the rectification columns of heavy fractions, in which hydrocarbons with the number of carbon atoms of 4 and 5 occur.

The gases from the upper part of the column are fed to drying, moisture from the gas is absorbed by the absorbent.

Cartoon explaining the operation of the column.

The dried gas is fed to the gas separation unit, consisting of rectification columns and heat exchangers.

During gas separation the following fractions are separated.

In the first column the methane hydrogen fraction.

The second is the methane-ethylene fraction.

The third column is where ethylene is separated.

The fourth is where the propane-ethylene fraction is separated.

A cartoon explaining the processes taking place in the second column.

Ethylene leaves the column and is sent to the fine cleaning shop.

The fine cleaning unit complex includes refrigerators, alkaline scrubbers, dryers, rectification columns and other equipment.

Ethylene must be freed from impurities, otherwise polymerization will stop or a low-quality polymer will be obtained.

A laboratory for checking the composition of ethylene.

A laboratory technician checks for moisture in ethylene, the data is reported to the shop.

A cartoon explaining the purification of ethylene in scrubbers and refrigerators.

Continuation of the cartoon explaining the purification of ethylene in scrubbers and refrigerators.

Then the gas is compressed by compressors and sent to the polymerization shop.

The laboratory demonstrates the conversion of ethylene into a polymer in the presence of a catalyst complex.

The complex consists of two components.

After a chemical reaction between them, the complex catalyst is formed, which converts ethylene into polyethylene.

The preparation of the complex catalyst and its raw materials, as well as all the main processes of polyethylene production, take place under the protection of nitrogen breathing.

This is due to the fact that catalysts are fire and explosion hazardous.

One of the components of catalyst production, metallic sodium, explodes when interacting with water.

Catalyst shop.

Reactor in an isolated cabin.

The reactor is loaded from a separate room through pneumatic loading funnels.

To create reaction centers, crystalline iodine and ethyl bromide are added to it.

Reactor control panel.

Process indicators are automatically recorded by recorders.

A cartoon explaining the processes occurring in reactors.

Chemical formula of the reaction.

Sesquichloride contains excess chlorine, which negatively affects the quality of polyethylene.

This problem is solved by symmetrization of sesquichloride.

Symmetrization of sesquichloride is demonstrated in the laboratory.

For this, metallic sodium is introduced into the sesquichloride catalyst.

To protect against moisture, metallic sodium is delivered to the production facility in sealed drums.

The drums are fed to the melting department by a lift.

Safety precautions when working with metallic sodium.

To melt metallic sodium, it is necessary to maintain a temperature of 100 degrees.

The molten sodium enters the measuring tank and the required amount is sent to the reactor.

Cartoon showing the operation of a reactor for the production of ethyl.

When the ethyl is ready, the material is analyzed for concentration and the ratio of aluminum to chlorine.

Sample collection is carried out in strict compliance with safety regulations.

Sample analysis begins with acceleration in a centrifuge.

Part of the material is collected in a flask, and a weak solution of sulfuric acid is added there.

The solution is stirred on a magnetic stirrer.

A small dose of trilon B is added.

After ten minutes of exposure, an ammonia buffer is added, and eriochrome black is added as an indicator, zinc sulfate for titration.

It is necessary that the pH of the solution be within 7.8-8.3. After determining the percentage of aluminum and chlorine in the sample, the analysis data are reported to the workshop.

Having received the data, the operator turns on the feed of cold gasoline into the reactor.

Solid particles of sludge form in the ethyl solution.

Under nitrogen pressure, the ethyl solution is fed into a collector with a stirrer, and from there into a centrifuge.

Cartoon showing the separation of a sludge consisting of sodium chloride and aluminum from a solution.

The result is ethyl filtrate.

Removal of sludge.

Incineration of sludge.

Cartoon showing the production of finished ethyl from the filtrate.

Finished ethyl is sent to the polymerization shop.

Panorama of the polymerization shop.

Pure gasoline is used as a diluent for titanium tetrachloride to prepare the complex catalyst.

Process control panel.

Gasoline quantity control meter.

Cartoon showing the production of the catalyst solution.

Each batch of the solution is controlled in the laboratory.

If the analysis data correspond to the norm, the titanium tetrachloride solution is fed to the complex catalyst mixer.

Ethal is fed to the mixer through a measuring vessel.

Hot water is fed to the mixer body jacket.

Cartoon showing the production of the complex catalyst.

After this, the catalysts are diluted with gasoline.

Then the ethyl is sent to the final diluent.

Cartoon showing the operation of the final diluent.

Continuation of the cartoon showing the operation of the final diluent.

Cartoon showing the operation of the ethylene polymerization reactor.

Before the polymerization process begins, the laboratory takes a sample to check the activity of the complex catalyst.

Using a glass model of the reactor, we can see the polymerization process and the formation of polyethylene.

The reactor is placed in a heater.

First, the reactor is purged with dry nitrogen.

Then the catalyst complex is poured in and heated to bring the temperature to 30 degrees.

After 5 minutes, the catalyst complex is diluted with gasoline.

The nitrogen supply is stopped and ethylene gas is introduced into the reactor.

The amount of ethylene entering into the reaction is noted on the chronometer every 3 minutes.

Ethylene molecules, contacting with the particles of the catalyst complex, form the polymer polyethylene.

The polyethylene particles, which are becoming more numerous, form a thick suspension.

After an hour, the ethylene supply is stopped and isopropyl alcohol is poured into the reactor to decompose the catalyst complex.

Polyethylene particles are insoluble in gasoline and alcohol.

The solution becomes transparent.

After stirring for 30 minutes, the reactor is stopped.

The polyethylene suspension is filtered on a funnel and dried.

The yield of the polymer and the activity of the catalyst complex are determined by weighing the dry powder.

The reactor in production, the same processes occur in it as in the laboratory reactor.

A cartoon showing the polymerization processes in a reactor in production.

Chemical formula of the process.

The quality indicator of the polymerizate in the reactor is monitored every hour in the laboratory.

The main quality indicator is the viscosity of the melt of the obtained polyethylene.

Viscosity testing apparatus.

If the melt index in grams corresponds to the specified number, the process is continued unchanged.

The suspension goes to the collector.

Suspension composition.

The aluminum and titanium compound are removed from the polymerizate.

A cartoon explaining the process of washing the polymerizate from the catalyst complex.

Along the path of the suspension, a small amount of isopropanol is introduced into the polymerizate to stop the polymerization process.

In a centrifuge, the solvent is separated from the suspension along with the remains of the catalyst complex and low-molecular polymers.

Cartoon about the operation of a centrifuge.

Continuation of the cartoon explaining the process of washing the polymer from the catalyst complex.

The device in which the compounds of the catalyst complex are decomposed.

Cartoon explaining the operation of the third-stage centrifuge.

Composition of the washing solution.

To remove the remains of the washing solution from the polymer, the polyethylene powder is fed from the hopper by screws into the drying section.

In the drying section, the polyethylene is dried under vacuum, which is provided by a pump.

Cartoon explaining the operation of the drying section.

From the polymerization shop, the powder is fed to the homogenization section with nitrogen.

The purpose of this process is to combine powder batches with different properties, they are averaged.

Batches with similar self-melting indexes are mixed to achieve homogeneity.

Cartoon showing the homogenization process.

As a result of homogenization, a large batch of powder with the same properties is obtained.

It passes through a vibrating screen to remove foreign impurities and enters a chamber feeder, from where it is transported to the granulation department using compressed nitrogen.

In this department, the average polymer powder enters the dosing mixers, where mixtures of different grades are prepared.

In the centrifugal and high-speed mixers, various concentrates of dyes and stabilizers are prepared.

The prepared mixture goes through a hopper to the granulation department.

After passing the intermediate mixer, the polyethylene enters the granulator hopper.

Before starting the granulator, electric heaters are turned on.

A cartoon explaining the operation of the granulator.

To prevent the granules from sticking together, they are constantly sprayed with water.

The vibrating sieve accelerates the drying of the granules, separates the stuck lumps and moves them to the hopper of the packaging machine.

Packaging of polyethylene granules in bags.

Samples of polyethylene products.