Turning tyres into diesel fuel

Used tyres can be turned into black gold or more precisely into a quality diesel fuel with a new tyre recycling technology, according to AAA Recycling.

Waste tyres are intractable waste and cause considerable concern for the environment not only in the storage requirements of used tyres a year. They are also an inherent fire danger and can result in the release of toxic gases into the atmosphere. This intractable waste adds greater pressure on the current land filling policy of many councils.

The technology can be used to rid this waste in an environmentally-friendly manner. There are no toxic gases produced and the final products of diesel, carbon black and steel are reusable in many ways.

As there is no molecular change in the manufacture of tyres, the catalytic process is now available to convert used tyres into fuel, carbon and steel products. It can restore the waste rubber to its original components.

The process has the capability of cracking waste rubber under normal pressure at low temperatures due to a German-Japanese engineering breakthrough. The catalyst results in a high rate of conversion of waste rubber to good quality fuel. The diesel fuel has been quality tested and meets the SH/TO356-1996 fuel standard.

The computer-operated plant takes the initial fuel liquid and readjusts it through separation refining to achieve the fuel standard. This fully enclosed process greatly reduces the environmental problems of many conversion technologies and community concerns of such manufacturing within community.

Waste tyres are collected and cut into 3-4 pieces added to cracking catalyst and a base oil. The air is heated either by gas or 10% diesel produced. The hydrocarbon molecules are transformed in a gaseous form by dynamically creating small chains of hydrocarbons. The diesel obtained is decoloured and any waste is removed including sulfur, manganese and aluminium. All is completed in a closed environment at 350°C, thus preventing the production of undesirable coke and toxic gases such as dioxins or furans.

Tyre pieces - reaction of catalytic cracking - fuel condensation - distillation and purification of fuel to meet required standards.

The techniques for separating carbon black following the cracking process are: filtration - magnetic sorting - crack and crushing through air flow - deoxidation - air circle sedimentation - final carbon black product.

The technology is designed to process about 40 tonnes of tyres in an eight hour shift. The products produced include: diesel 19 tonnes; carbon black 15 tonnes; and steel 6 tonnes. 40 tonnes of waste rubber is equivalent to 4000-5000 8 kg tyres per day.

Truck tyres and tyres from earthmoving equipment can also be processed once they are cut into suitable sized pieces. The technology can also be applied to plastics.

The plant floor space is only an area of approximately 1200 m2, which includes a control room and a laboratory 200 m2. In addition, storage area is required for tyre pieces 4000-6000 m2.