Waste tyres make an excellent fuel because of their high heat value. Each tire has large energy potential. The heating value of an average size passenger tire is between 13,000 and 15,000 Btu/lb., which compares with about 10,000 to 12,000Btu/lb. for coal. The primary reason for cement manufacturers to use TDF is to save fuel costs. A secondary reason is to reduce their Carbon Dioxide and other fugitive air emissions.
The cement industry is one of the largest users of coal in the world (apart from the power industry). Approximately 40% of the CO2 generated in the production of cement clinker arises from the carbon content of the fuels (predominately coal) used. This arises due to the traditional reliance on fossil fuels within the industry.
Several characteristics make scrap tyres an excellent fuel for cement kilns. The very high temperatures and long fuel residence time in the kiln allow complete combustion of the tyres. There is no smoke, odor or visible emissions produced. Any ash is incorporated into the final product, therefore there is no waste. The metal wire contained in the tdf is captured as a raw material or ingredient in the cement making process.
To address this traditional reliance on fossil fuel sources, the European cement industry has been progressively introducing Alternative Fuels (AF) for the past 30 years. This strategy has seen a significant displacement of this reliability on fossil fuel sources with approximately 20% of the energy used in firing cement kilns within the EU now accounted for by the use of lower carbon intensity alternative fuels. This is strategy is being mirrored in Ireland. http://www.cement.ie/sustainability/alternative-fuels.html
More than 4m tonnes of new tyres of all types were placed on the European Market in 2013 (Source ETRMA), resulting in about 3.5m tonnes of tyre waste being produced. If this waste were used instead of coal in the cement industry, CO2 emissions from cement manufacture would be reduced by over 4m tonnes, and EU imports of coal reduced by 4million tonnes.