Innovative Waste Heat Recovery in Cement ProductionReducing CO₂ Emissions and Energy Consumption

Abstract

This paper explores the potential of Waste Heat Recovery (WHR) systems to enhance sustainability and energy savings in cement production. The cement industry is energy-intensive, with significant waste heat generated from kiln operation and clinker cooling processes. By recovering and utilizing this waste heat, WHR systems can generate electricity, reduce grid energy consumption, and mitigate CO₂ emissions. This study focuses on implementing a WHR system at the Cement Plant. Using data from the plant, including flue gas temperatures of 368°C and hot air from the clinker cooler at 244°C, a comprehensive model was developed in Aspen plus V12 to simulate the WHR system integrated with the plant's operations. The WHR system was designed around an Organic Rankine Cycle (ORC) with carefully selected working fluids optimized for low- to medium-temperature heat recovery. The techno-economic analysis reveals that the system could generate 27.5 GWh of electricity annually, reducing grid electricity consumption by 25%. This corresponds to approximately 16,967.5 tons of CO₂ emission reductions annually, given a high electricity emission factor of 0.617 kg CO₂/kWh. The financial analysis indicates that the levelized cost of clinker production with the WHR system is $2.54 per ton, with a payback period of 9 years. This demonstrates the economic viability of the system, alongside its environmental benefits. The study highlights WHR systems as a practical solution for improving energy efficiency and sustainability in cement production, particularly in regions with high carbon-intensive electricity grids. The findings provide a strong case for the broader adoption of WHR technology in the cement industry.