A continuous recycling process could turn the estimated 50 million used tyres that are discarded in the UK every year into oil for motor fuel.
Used Tyre Distillation (UTD) Research of North Wales developed the process, called continuous reduction distillation, that produces oil, gas, steel and carbon black — a solid residue — from the tyres.
Partners from Bangor University’s School of Chemistry, which helped distinguish the grades of oil produced and advised UTD on refining it, has been helping to develop the technology and market it worldwide.
While carbon black, oil and gas have been produced from used tyres in different labs before, UTD claims to be the first to successfully scale up the process.
Using a furnace operating at between 300 and 600ºC the tyres are subjected to pyrolysis which in turn produces a gas (predominately methane) oil and carbon black.
With a modification to the process, for which the company is applying for a global patent, the team successfully managed to get the plant to work continuously. According to UTD the process also produces sufficient gas to power the process, making the entire procedure energy neutral.
’We’ve taken a basic principle and modified it to get the process to work 24 hours a day, seven days a week,’ said UTD marketing director Paul Archer. ’We’ve also put a lot of work into the commercialisation and value of the products.
’The process produces an oil with a high calorific value and is not as complex as crude oil, so it’s easier to break down’, he added. ’We also know it produces sufficient gas to run the plant and we are pretty sure it produces in excess of that. We are still waiting for some gas analysis to find exactly how much that excess is, but if it is sufficient it may be possible to run a generating system alongside the plant.’
Bangor’s Dr Vera Thoss, an environmental chemist, has been working with UTD to help categorise the various products of the process.
’I find the concept very attractive,’ she said. ’We take used car tyres, which we’ve got a lot of, and convert them into something which could be used in the future.
’The pilot plant provides about 20 litres of oil a day, from around a dozen tyres. The idea is to seriously scale it up and what the team is looking for is investment to make that happen,’ said Thoss.
’The key issues now are controlling the process better and looking at what we can get out of it. The oil could be refined and we will see what we can do to activate the carbon black to make active charcoal out of it.’
With the feasibility proven, UTD’s Archer believes the next stage is getting the investment to build a new full-scale plant.
’We are planning on running one plant in North Wales and licensing the technology globally,’ he said. ’The one in Wales is due to be running in 12 months. we are ready to build the plant, all that is setting us back now is the investment.’
He said that the plant is looking to process around two million tyres a year, which should produce around six million litres of oil, 5,500 tonnes of carbon, 2,500 tonnes of steel, with the remainder gas.
’We’ve had inquiries from all over the world, and as prices for oil and carbon increase and we see more news items about shortages, I’m confident we will get the investment,’ he said. ’We are expecting a £2m-2.5m revenue and a profit of around £1m from the new plant, and with the global licensing our five-year plan should see us with an income of around £10m at the end of year five.’
The oil produced by the plant has been combined with diesel and used in test vehicles at North Wales’ Anglesey racetrack and there has been interest from the Energy Efficient Motorsports(EEMS) programme.
’EEMS is looking into running their support vehicles on the oil and we are looking for someone to refine it to run the cars [using the track] on a long-term basis without adding any diesel,’ said Archer. ’We are also looking for a racing team that might be able to use the fuel.’