Tarmac Buxton Lime and Cement say the trial use of tyre chips as an alternative fuel in their high-temperature cement kiln at Tunstead Quarry, near Buxton, has been a resounding success, with all of the ‘Critical Success Factors’ set by the Environment Agency for the trial having been met.
Quarry Management reports that, the equivalent of 2 million old tyres have now been used and the trial has demonstrated that using tyre chips gives significant environmental benefits, including a reduction in the use of fossil fuels and a 15% cut in emissions of oxides of nitrogen (NOx). The very high temperatures, long combustion times and excess air in the cement kiln also ensure complete combustion of the tyre chips during the process, so there is no black smoke or smell.
‘This is good news for the local environment and also for wider society as fossil fuel consumption has been reduced while a beneficial use has also been found for a waste which was previously disposed of in landfills,’ said fuels development manager Hasan Bobat.
The trial, closely supervised by the Environment Agency, was carried out in the latter part of 2006 and early 2007. State-of-the-art monitoring methods compared plant emissions when using conventional fuels (coal and petroleum coke) with replacement of up to 50% of heat requirements with tyre chips.
Owing to the success of the trial, Tarmac Buxton Lime and Cement are allowed to continue using the substitute fuel while the Environment Agency considers the trial results in detail before deciding whether to give permanent permission for the use of tyre chips at Tunstead.
The tyre chips – sourced from cars and light vans only – are supplied by Newton Aycliffe-based used-tyre collection and processing company Credential Environmental. At their sites in Durham, North Yorkshire and Wednesbury in the Midlands, they recover tyres that can be reused or re-treaded before chipping the remainder to produce a variety of products, including cement kiln fuel and aggregate replacement materials for use in civil engineering applications.