Rubber waste originated from car and truck tyres is almost equal in heat value as gasoil and even 25% more effective than coal. There are extremely high quality requirements for the rubber waste used in the burning process at power plants. The particle size of tyre shred needs to be homogenous and no remnants of metal wires are tolerated in the furnace.
Quality issues in particle size as well as uneffectiveness in the shredding process were the Achilles heel for our customer Lassila-Tikanoja Ltd (L&T) who provides rubber waste for the energy industry. L&T has operations in Finland, Sweden, Latvia and Russia.
Earlier, the process of shredding car and truck tyres at the L&T site was done in three separate phases. First, tyres were ripped up with a rented tyre cutter. Secondly, tyres were pre-shredded with Doppstadt 3060K. After these phases the particle size of tyre shred was still not homogenous enough. For that reason, the material needed to be processed an additional third time in order to achieve the required 80 mm particle size and make sure that the end result is pure rubber without any metal wires.
Faster process, higher quality and less expenses
After purchasing the TANA Shark 440DT the whole tyre shredding process at the L&T site was renewed and it is now handled with one single machine. If the two shredding processes would be carried out with same presumptions, the process would be as the Picture 1 below illustrates.
As demonstrated above, TANA Shark 440DT takes care of the whole shredding process in two phases. During the pre-shredding phase the whole car & truck tyres are cut into 3-6 pieces. This also loosens the metal wires inside the tyres. In this process the machine is driven with all counter-knives, without screen and without the overband magnet.
In the primary shredding phase unwanted metal wires are removed by using an over-band magnet and the 170 mm screen is inserted below the rotor to generate the wanted homogenous particle size of 80 mm.- What has amazed us is the fact that using a single machine gives us the required end result. If possible, even more amazing is that this is achieved with 5-10 litres lower fuel consumption per hour than before, says Kari Soini from L&T Finland.
– What we have learned is that using 75% of the maximum power and torque for tyres gives us the best operating efficiency, says Soini.