Electrified externally heated rotary calciner for calcination of cement raw meal

Abstract

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.