Kiln exhaust streams from clinker cooler and the kiln preheater system contain useful thermal energy that can be converted into power.
- Nearly 40 percent of the total heat input is available as waste heat (in dry process cement plants).
- Clinker coolers releases large amounts of heated air at 250 to 380°C (from 330 to 540 MJ per ton of Clinker).
- Kiln preheaters releases flue gases at 300 to 450°C (from 750 to 1,050 MJ per ton of clinker). Heat released by kiln preheaters is partially recovered by raw mills and/or coal mills.
- The cement industry has a significant environmental footprint due to the extensive amounts of energy and raw materials used in the process (5% total CO2 emission -IEA 2009)