Simulation of oxy-fuel combustion in cement clinker manufacturing

Abstract

A thermodynamic process model is used as an evaluation tool. Full oxy-fuel combustion is evaluated for circulation of 20-80% of flue gases to the burn zone of a rotary kiln. The full oxy-fuel combustion simulations exhibit altered temperature profiles for the process. With 60% recirculation of flue gases, the temperature in the burn zone is comparable to the reference temperature, and carbon dioxide concentration in the flue gases increases from 33 to 76%.If water is excluded, carbon dioxide concentration is 90%. The partial oxy-fuel combustion method is evaluated for 20 and 40% recirculation of flue gases from one cyclone string to both calciners. Fuel and oxygen feed to the burning zone and calciners are optimised for the partial oxy-fuel scenario. The lowest specific energy consumption is desired while maximising the amount of carbon dioxide theoretically possible to capture. By introducing partial oxy-fuel combustion with 20% recirculation of flue gases in the carbon dioxide string, total carbon dioxide emissions increases by 4%, with 84% possible to capture. Within the limits of the model, the introduction of full oxy-fuel and partial oxyfuel combustion is possible while maintaining product quality. When simulating partial oxy-fuel combustion, the energy consumption will increase even when no power consumption for the production of oxygen is included.

Thermodynamic data for cement clinkering

“…shows the conventional CO 2 pressure in the kiln (10%v or 0.1 atm); the CO pressure is normally at or above this isobar. The curvature of the field boundaries shows the upper temperature limit of stability of spurrite which is enhanced in CO 2 -rich atmospheres as may occur in as oxyfuel combustion [64,65] which typically generate atmospheres rich in CO 2 .…”

Oxyfuel combustion in rotary kiln lime production

“…There are publications on oxyfuel in other industrial processes, e.g., cement production , iron and steel production , and power production . The technology has been demonstrated, e.g., for power production, but there are no full‐scale plants in operation.…”