Recycling of polyethylene into granules. Polyethylene recycling is a priority task for industry and ecology How many plastic bags are recycled

Collection of polyethylene

Our company does not process all types plastic bags, but only film, bags, bags, defective production of stretch film (the so-called shrink film) and LDPE.

PVD is polyethylene high pressure or, as it is also called, low density polyethylene. LDPE waste can be generated during the direct production of polyethylene film. A lot of waste - in stores (packaging of bottles, boxes, boxes), glass factories (from packaging of bottles, cans), distilleries and breweries (from packaging of containers or finished products).

Stretch film is a linear high-pressure polyethylene (LDPE). It can stretch a lot. Due to this property, as well as increased resistance to punctures and tearing, stretch film is used for packaging various goods, in particular on pallets (pallets). Stretch film waste is mainly generated and accumulated in warehouses of any value, at customs terminals, in logistics centers, etc.

But the popular T-shirt bags made of HDPE (polyethylene low pressure) and "biodegradable" packages, which can be found, for example, in the "Azbuka Vkusa", we do not recycle. Polypropylene film, PVC film, bubble film, polyamide film, LDPE+PP, LDPE+PA multi-layer films, and double-sided two-color films are also not suitable. Finally, we do not accept film contaminated with oils, fats, food waste and pesticides.

Sorting

We transport the collected polyethylene to the warehouse. Up to 100 tons of film waste can be stored here, naturally in pressed form. At the first stage, the raw materials are carefully sorted. They separate stretch from LDPE, reject types of films that cannot be processed by our facilities.

Crusher

After sorting, packages of a certain color are put into a crusher. In it, on V-shaped knives (in our circles, this type is also called “dovetail”), the film is crushed to particles of uniform size. The knives are powered by an electric motor.

Washing

From the crusher, through the pneumatic conveyor, the so-called "crushed" gets into the sink. In it, with the addition of special cleaning solutions, the "crushed" is cleaned of dust and other non-polyethylene inclusions.

Cooking

The next stage of processing is agglomeration. In it, the so-called "cooking" takes place. The operator loads clean "crushed" into the working chamber through the loading window. The raw material enters the rotating rotor along the guides, is crushed by knives and due to friction against the body and between themselves is heated to the temperature of plasticization. In this case, the entire volume of loaded raw materials becomes similar to a mushy mass.

When the material becomes homogeneous, "shock" water is added to it, as a result of which the material is rapidly cooled and sintered into separate small balls. irregular shape. For some time, the agglomerate is dried at natural temperature. environment and unloaded into a prepared container to go to the final stage. The cooking process itself lasts from 5 to 10 minutes.

Granulation

The process of granulation can be compared to scrolling minced meat through a meat grinder. Agglomerate, which we received at the previous stage, is loaded into the extruder hopper. It is called so because the production of granules is based on the extrusion method - forcing the molten mass through a forming hole.

In general, our “minced meat” from boiled bags is melted under the action of heaters and pressure created by a rotating screw. The polymer melt is forced through a filter into a rotating extruder head. So-called threads are already coming out of it. For cooling, we run them through a water hose, and then into knives, where we cut them into homogeneous granules.

Storage

The granules are packaged in clean polypropylene bags, approximately 50 kg each. special conditions storage is not required, but it is desirable that it be a dry room.

Finished raw material

The resulting granules, depending on the composition and color, we sell. Natural color stretch granule goes to the production of secondary stretch. The natural color LDPE granule is used for the production of secondary shrink or technical film. Colored LDPE granules are mainly used for the production of garbage bags.

Polyethylene has excellent performance characteristics, due to which the material is widely used in production and in everyday life, naturally, this has led to an increase in the amount of waste in landfills. According to statistics, up to 10% of all household waste in the trash bins account for polyethylene materials.

Film waste do not rot, do not dissolve, do not decompose for decades, emit substances hazardous to the environment, pollute water and soil. When burned, polyethylene does not burn completely, forms toxic dioxins - dangerous poisons that can accumulate in living organisms and tissues, leading to the most dangerous consequences including ulcers, dermatitis and even mutations.

There are various options for recycling and disposal furniture film waste. Among them, pyrolysis should be singled out, which, for all its positive qualities, has not become widespread, since with economic point of view, such a method is justified only if there is major sources raw materials. Practice shows that the most effective method recycling of polyethylene products is to organize lines for its reuse.

Recycling allows you to reduce the cost of manufactured products, reduce the cost of raw materials, save resources and make a profit directly from waste.

Types of polyethylene waste

Polyethylene today exists in the most different types and forms, the film can be of varying degrees of contamination and readiness for further use in production. There are several groups of experts polyethylene waste:

1) Technological marriage.

This category includes from 1 to 10% of all polyethylene waste. Defective products, including film, bottles and other products directly at the factory, may be sent non-recycling as returnable raw materials.

2) Homogeneous consumer waste.

3) Waste in landfills.

Waste from production and domestic use: bags, film, bottles, etc.

It is also customary to divide film and polyethylene waste into groups according to the degree of preservation and contamination. The most common categories are products with partially lost useful parameters and materials with minor damage.

Plastic film waste are mixed with other waste in landfills, therefore modern recycling methods usually include two separate stages of work:

• separation of homogeneous materials from waste;
• processing of obtained polyethylene products.

Waste types and recycling methods

The type of raw material, its condition, contamination, homogeneity and other individual characteristics determine which stages in the processing process it will go through. In most cases, the film and other polyethylene products are sorted, cleaned, crushed, crushed, fractionated, granulated. Only after that polyethylene is used to create new products.

Large polyethylene products are cut on special machines before processing, and then sent to crushing and grinding machines. Cleaning of film and other waste from contamination is carried out on special washing lines using powerful chemical solvents that can remove all impurities from polymer waste.

Recycled plastic has a high viscosity, therefore, the granulation of materials is carried out under the influence of a very high temperature in special devices equipped with choppers, filters and pumps. Powerful granulators give the chance to process the most different polyethylene waste.

How can you use recycled polyethylene

Film waste and other plastic products can be recycled into various useful products. For example, mixed waste containing a large amount of foreign inorganic and organic elements can be processed using intrusion or casting. These available ways processing allows you to create parts for enclosing plastic structures.

Film, disposable bottles and other containers are most often used to re-create the same products. Problems can arise only when working with materials with a highly modified structure; they can only be used to create massive plastic products of low strength.

Any plastic waste can be processed into crumbs used in construction, production of equipment parts and vehicles. Modern car manufacturers are paying more and more attention to recycled materials and making parts of doors, bumpers and other necessary things from recycled plastic.

With the proper organization of recycling processes, it is possible to ensure the yield of secondary raw materials at the level of 70-80% of the initial volume of polyethylene film, PET bottles and other products. Despite the complexity of processing, the direction is actively developing, as it allows organizing efficient waste-free production.

In life modern man polyethylene is used everywhere. Almost every home has a variety of packages. The better the raw material, the more difficult it is to dispose of and the longer the period of its decomposition. processed into new products. This is what is discussed in the article.

Disposal

The widespread use of polyethylene has led to environmental problem- accumulation of waste in landfills. It is estimated that these products account for 8-10%. The material does not rot, it is resistant to acids and alkalis, it almost does not dissolve, it takes many years to decompose, and hazardous substances are released that pollute the soil and water bodies.

Polyethylene does not burn completely, forming toxic dioxins that are harmful to all living things: poisons accumulate in the body, which causes dermatitis, ulcers, and mutations. Pyrolysis from this raw material has not been widely used - it is economically beneficial when in large numbers raw materials (over 20 thousand tons per year).

The best option is to hand over polyethylene. Recycling allows you to use this opportunity to save resources, reduce the cost of products, reduce costs.

Waste types

Polyethylene waste differs in shape, composition, location, contamination, level of preparation for secondary use. They are divided into several groups:

1. Technological marriage (2-10%) - practically does not differ from standard products. It is used as a returnable raw material or low-grade commercial products.
2. Waste industrial use- films, containers, containers, pipelines, cable sheaths, non-working products.
3. Part of the waste in landfills - films, bags, bottles, household items.
4. According to the level of preservation: slight destruction and partial loss of the desired characteristics.

Polyethylene waste is mixed with the rest of the waste. There are 2 directions for polyethylene recycling - separation of homogeneous products and processing in a mixture of waste.

Recycling

Reception of polyethylene waste is carried out by specialized companies. From the type of product, they determine what the technological cycle of processing will be. It usually includes sorting, cleaning, fractionating, grinding, crushing, agglomeration, granulation and product formation.

Large fragments are cut with circular saws or band saws. Jaw or rotary crushers, hydro grinders, devices cooled by liquefied carbon dioxide are suitable for small products.

Cleaning of contaminants is carried out in places of washing and on washing lines with the function of solvent recovery. From thermoplastics, polyethylene is extracted using the screening method with separation or flotation. To reduce the volume, degassing, cleaning products are sintered. The agglomerate is used as a commercial product or used for granulation to create secondary granules of the highest quality.

Recycled polyethylene has a high melt viscosity. Its granulation is carried out with high temperatures in apparatuses in which there are rotor-knife grinding crushers, pumps for the melt. These granulators are needed for recycling, degassing and modification of waste.

Features of work

During the processing of packages, several stages are carried out. The first cycle has practically no effect on the decrease in consumer characteristics of new products. But with each stage, the raw material acquires negative characteristics, which is why it can be used for special materials. Waste is used to make new products. The processing technology is as follows:

1. There is a collection of raw materials: films, bottles, garbage. Sorting is done manually or mechanically. If the waste is divided into waste paper, glass, paper, PET, then it will be possible to reduce the amount of garbage for disposal.
2. Raw material goes to washing devices. The stage is required to eliminate dirt, foreign objects. If the products are handed over to the receiving points, then the quality is checked in order to assign a cost.
3. Raw materials are crushed by crushers.
4. If it contains moisture or impurities, then processing is carried out in a centrifuge.
5. The material is sent to a drying chamber for heat treatment.
6. The work is finished and the material can be reused. They make universal products - polyethylene films, bags, packaging containers, pipes.

What comes from waste?

The collection of polyethylene waste allows you to obtain various products. Mixtures with a large amount of foreign inclusions are processed by casting or intrusion at low pressure. This low-cost option allows you to get lightly loaded products for decorative street fencing.

Reception of polyethylene waste with a short period of use (containers, films, bottles for single use) is carried out for processing into products of this type. If the materials have a crushed structure, then large products with low strength are obtained from them.

Now the sphere for the manufacture of composites from secondary polymers and fillers has been developed: crumb rubber. They are used in the production of containers, finishing tiles, furniture, decorative elements for cars.

The secondary granule is used as an additive to polyethylene in the manufacture of standard products or as a binder in composites for the production of pressure pipes, large containers. This raw material is used to create containers and packaging for non-food products, building films, and pipelines. This area, although complex, is actively developing.

Outcome

Recycling will reduce the amount of garbage in city landfills. Polyethylene and plates practically do not decompose. But on their basis, new products are obtained that are useful in various fields human life.

Recycling of polyethylene into granules is a very effective business, since this task is in the public interest associated with the disposal of a huge amount of polyethylene waste, and at the same time satisfies the need of manufacturers for granulated polyethylene.

This project involves working only with transparent high-density polyethylene films, since narrow specialization significantly increases the efficiency of the enterprise.

Transparent granules of the first grade will be supplied, the profitability of production of which is much higher, and the need for them is greater than for products recycling colored polyethylene.

The technology used to process polyethylene into granules is very typical for the processing of plastics and many other materials.

The raw material is subjected to crushing, after which dirt and foreign elements are removed from it with the help of a sink. After removing water in a centrifuge and completely drying, the raw material passes through a compacting agglomerator and enters the granulation operation, which completes technological process recycling of polyethylene into granules.

On the scale of production envisaged by the project, multi-ton installations of gigantic dimensions are not required, for the placement of which specialized buildings and powerful foundations are required. There is no need for a railway line and access roads, power substations and provision of industrial sewage.

For the proposed production, a conventional workshop with rooms for storing raw materials and finished products is quite suitable.

The required amount of storage space can be estimated based on the fact that the capacity of the equipment planned for purchase is 250 kilograms of pellets per hour, and the raw material processing ratio is close to 100 percent.

With two-shift operation, the production capacity is about 75 tons of products per month.

An investment of 4.5 million rubles is required to launch the project.

The payback period of the project does not exceed 6 months. The expected monthly profit is 1.4 million rubles.

The investor is offered 50 percent of the profit received.

Currently, there is an agreement with large sorting companies that are ready to supply up to 120 tons of film waste per month, which will be used as raw materials. At the same time, two enterprises near Moscow have already expressed their readiness to purchase the entire volume of pellets produced at an agreed price.

We all understand that waste is somehow recycled, but how is this done? Few people know. There are certain differences between the processing of industrial and household plastics, since polymers have different properties.

Similarly, secondary raw materials, that is, polyethylene, have their own properties, which often do not meet the requirements. This is comparable to the fact that the processing of polyethylene involves materials that differ in molecular structure. In addition, the plasticization process contributes to an increase in the quality of the processed material.

Recycling processes

Ordinary polyethylene, including the material used for packaging, has a long service life. It must be remembered that when using industrial film, it is exposed to atmospheric factors:

• temperature difference
• Sun rays
• the film may be covered with a layer of dust that is difficult to remove when carefully cleaning the film

As regards the conditions, the processing of polyethylene does not differ in principle from the processing of virgin material. But the recycling of polyethylene waste, in some cases, undergoes minor changes, so there are restrictions on the number of polyethylene processing cycles.

Our days

AT modern times The most advanced way to recycle polyethylene is to use an intermediate material to replace wood materials. The recycling process itself requires special cleaning of the secondary product (for example, containers for fuels and lubricants).

Most wide application recycled PE found the production of canisters by blow molding. These canisters are made completely on a waste basis or with extrusion, primary granulate (in this case, a layer of secondary polymer creates a core between 2 layers of 1st polymer). The resulting products are used for bottling various detergents by a large number of companies.

The second method is considered - irrigation pipes. The diameter of these pipes reaches up to 630 mm. When performing injection molding, recycled polyethylene has a lower percentage. This technology is used for cladding panels, garbage containers, etc.

As for the equipment, the processing of polyethylene has different kinds and stamps. Many manufacturers are engaged in the production of equipment, successfully entering the Russian market.