CEMEX has published detailed test results from a trial using chipped tyres as part-replacement for coal to fuel the cement kiln at Rugby Works in Warwickshire. Data show a marked reduction in certain emissions from the chimney during the trial. Most notably, oxides of nitrogen which affect air quality, decreased by 30%.
A preliminary report with results from the 1,000 hour trial completed last December describes the Work’s successful performance against each of the following critical success factors, which have been identified in the Work’s permit (IPPC Permit BL7248):
Compliance with emission limit values
Process efficiency
Improved overall environmental impact
Acceptable assessment by Environment Agency Officers
Stable operations
Stability between fuel changes
Quality assured data
There are about 40 million used tyres scrapped each year in the UK alone. In the past, the majority have been dumped in the ground in landfill sites. In 2003, an EU directive banned this practice with whole tyres and in 2006 this will also apply to shredded tyres. To help solve this problem, the government has been looking at ways in which old tyres can be safely dealt with, including using them as a fuel in cement kilns.
In addition to the direct environmental benefits of reduced emissions, using alternative fuels, like tyres, have indirect benefits. This includes recovering energy from what would otherwise be considered a waste material, thus minimising illegal dumping, reducing landfilling and preserving fossil fuels for future generations.