Recycling of tires

RECYCLING OF WORN-OUT AUTOMOBILE TIRES (WAT)

Coral GROUP is glad to present one of its finest developments, an ecologically clean and financially beneficial method of recycling of worn-out automobile tires.

Worn-Out Automobile tires

Anti-Penetration Wrapping Material

The pyrolysis method for recycling of WAT is an innovation technique that uses an electro – magnetic field principle to ensure uniform heating of WAT, without access of oxygen.

Pyrolysis is the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam.

In industry, it may be used to convert one single chemical; for example, ethylene dichloride is pyrolysed to vinyl chloride to make PVC. It may also be used to convert complex materials such as biomass or waste into substances that are either desirable or less harmful.

The method was tested by the centre of chemical technologies of academy of engineering scinces of Ukraine for ecological cleanliness (download pdf).

Pyrolysis has been numerously used in WAT recycling before, however, most of existing technologies use outside heating techniques, thus creating too high a temperature. The method developed by the company does not have this drawback.  

In order to ensure maximum efficiency the WAT are cut prior to entrance into the pyrolytic chamber, the technological process requires the pieces to be 10×10 cm; therefore a special cutting apparatus was developed.

The apparatuses – shredders are analogous to some mass produced machines, however, they are highly mobile and production-efficient. The shredders can be stationary, to be placed on landfills and in the recycling facilities to shred the whole tires, or alternatively, they can be mounted on trucks that move around the tire gathering stations or tire-change centres to shred the tires before transportation.

Schematically the recycling technology looks as follows:

First the tires arrive at the recycling facility, whole or shredded. The whole tires are shredded by the stationary apparatuses. Then an automated loading system loads the tires into the reactors to undergo pyrolysis. After the pyrolysis has been completed, the tire separates into three distinct fractions: solid, liquid and gaseous. The three fractions are separated: the gaseous fraction elevates, and moves through special tubes to the distillation station, while the solid fraction falls into the bottom zone of the pyrolysis chamber.

The gaseous fraction is then distillated and liquids are extracted. The leftover gasses are comprimated and three typed of gasses are separated: light gas, heavy gas (Propane-Butane) and Divinil.

The light gas is transported to a gas – power generator, which provided a part (up to 20%) of the power for the process, the other gasses are stored and are products to be sold.

The liquid fraction is further distillated, to produce kerosene, benzene, diesel fuel and black oil, all standardized products.

The solid fraction consists of metallic wire, which can be sold as scrap metal and carbon. The metal is then melted into blocks and sold. The carbon undergoes further purification processes and then is ready to be sold. There are two basic products produced from the carbon. One is technical carbon which is used as partial substitute for carbon black in rubber production; the types of carbon black currently produced can be even used in new tire production. The second type of product made from the carbon are absorbents. These products are used in oil refineries, chemical production, pharmaceutical production etc.

The artificial oil was tested for dengerous materials in Pridneprovsk centre of national medical academy (download pdf).

The distribution of the products is as shown in the graph below:

The fractional composition of the liquid materials (oil), shows that up to 85% of them can be used in motor fuel production, which is more than twice as much as one can get from natural oil, – Brent trademark.

Chemical composition of the solid fraction is such, that it can be divided into two parts: metallic wire and solid residue, which can be used, without further input, as fuel on power stations. From an economical point of view, it is better to wash-out the the solid residue with water, to get rid of mineral components, to get technical carbon and cindery rest. Technical carbon is an analog of carbon from candle coals. Most of the sulfur contained in the tires is present in the mineral part, as sulfides and sulfates and is not inherited after the wash-out process.

Ash rest can be used in cement production. The gas composition allows it to be compressed up to 50 atmospheres, like propane – butane, and can go into home usage or into production facilities. The sulphur cleaning of the gas is preformed as part of the process. Oxygen content is as in the natural gas. Caloric content is on the levels of prophane – butane. Therefore, the technology not only allows us to solve a serious ecological problem of worn-out automobile tires utilisation, which is currently present in most developed countries but also produce useful, materials of high quality.

The recycling process of worn-out automobile tires is ecologically clean and its economical value can be evaluated as being very high.

At early stages of development independent specialists tested the idea (download pdf1 pdf2).

Analysis of the liquid fraction before hydration can be seen in the tables below

Initial pyrolysis product “artificial oil”

Fractional structure of initial liquid
Up to 80C – 23%
Up to 320C – 68%
180C – 320C – 45%

Fractional Structure   Temperature C
Beginning of distillation88
10% at136
20% at166
30% at188
40% at238
50% at272
60% at290
70% at323
80% at245
90% at247

The holding Coral GROUP has constructed a mini-factory that uses the above stated technology, and shows the entire recycling process and the process of manufacture of final, marketable materials.

The mini-factory produces all the primary materials:

Artificial oil, Gas, Carbon, Metal

and then reprocesses them into value-added product: Fuels, Marketable gasses, Carbon black, metal bricks

The purpose of construction of the mini-factory is to finetune the technological solution within a full complex of production. The capacity of the facility is one tone of WAT a day, however, except this parameter all the other parts of the technology are present in full scale. Almost all the equipment present in the facility was designed by the Coral GROUP and is unique.

Most of it was specifically designed for the purpose of WAT recycling and constructed by different factories in Ukraine.

The facility consists of a cutting station, pyrolysis chamber with automatic loading and unloading mechanism, gas separation station, oil distillation facility, and carbon purification station. The mini-factory also contains a specifically made electrical system and a gas generator that utilises the light gas produced by the pyrolysis. The facility is fully automated with special testing computer system, that controls the process.

Currently the facility undergoes constant tuning, approximately four test runs a week are preformed, and needed corrections are made.

The facility produces different types of fuels: benzene, kerosene, diesel, black oil and hydron. Three types of gasses: light gas, prophane, butane and divinil. Scrap metal and carbon, which is reprocessed into carbon black.

Currently more than 40 professionals are working on this projects, with the help of laboratories in Dnepropetrovsk, Donetsk, Kharkov, Kiev and Sankt Petersburg.

 

Coral GROUP Rubber laboratory, Dnepropetrovsk.

Laboratory of chemical production and equipment, UDHTU, Dnepropetrovsk.

Laboratory of metallrgical fuel and reducers, NMetAU, Dnepropetrovsk.

Laboratory of general chemical technology, UDHTU, Dnepropetrovsk

R&D Institute of rubber industry “Elastic”, Kiev.

Stage 4 of this project has been completed, therefore, the facility is being currently used for demonstration and fine-tuning of the process. Coral’s specialists hope to maximise the efficiency of the process and may still come up with some crucial improvements, while the first large-scale facility is being built.