Going for the re-burn

Car tyres and other hard-to-dispose-of waste materials could be used to reduce NOx emissions from power stations, a UK research team believes.

A project at Leeds University will attempt to develop technology that uses tyres and waste plastics as an alternative to coal as part of a power plant’s ‘re-burn’ process. If successful, the project team hopes some of the most problematic materials could be turned from an environmental headache into an advantage.

An estimated 40 million old tyres have to be disposed of in the UK each year, and tough new EU regulations will come into force next year banning them from landfill sites.

Re-burning is a well-established technology for reducing NOx emissions. Around 90 per cent of the coal is burned in the main combustion chamber, and the remaining 10 per cent is injected further on in the process. This produces a pool of hydrocarbons that react with the NOx to produce nitrogen, thereby reducing NOx emissions by around 50 per cent.