Potential savings in the cement industry using waste heat recovery technologies

This work describes technologies especially suitable for enhancing cement production process efficiency and overall plant performance by preheating raw material or generating electricity, thus reducing thermal losses, costs, and carbon dioxide emissions. Assessed systems for this purpose include power cycles such as the Organic Rankine Cycle, Tri-lateral Cycle, and Kalina cycle, and alternatives currently under development, such as thermoelectric generators and supercritical fluid cycles. Likewise, the zones of the cement production process with the most significant waste-heat recovery potential are pointed out, focusing on clinkerisation, which accounts for most of the thermal energy expenditure of a cement plant. In addition, the total carbon dioxide emissions related to cement manufacture and the participation of each production stage are presented. Finally, the potential for waste heat recovery in the cement industry of the first six Latin American producers is reviewed, which covers 82% of the total production in the region, based on the thermal and electrical requirements reported in the literature. The potential for emissions savings of carbon dioxide is estimated under the emission factor for the electricity system in each country.