Electrified externally heated rotary calciner for calcination of cement raw meal

The cement industry can reduce its CO₂ emissions by electrifying the calciner. It can avoid emissions from fuel combustion and produce pure CO₂ from the calcination reaction (CaCO₃ → CaO + CO₂) for direct capture. A differential-algebraic equation (DAE) model of an electrified rotary calciner was developed and validated against experimental results. The heat transfer coefficient was around 30 W/(m²K), with the calciner inclined at 15°. This value increased to 80 W/(m²K) by reducing the inclination to 2°. The rotary calciner for producing 1 Mton/yr clinker with an internal diameter of 5 m needs a length of 485 m to reach a calcination degree of 94 %. The large system size suggests that this calciner may not be suitable for full-scale production. However, it can still be used for small-scale green production of calcined limestone.