3).
In the next step the calcium carbonate is thermally decomposed in a classical Calciner at 900°C. This is like the production of lime or cement and releases carbon dioxide (CaCO
3 CaO + CO
2). Unlike classical calciners, the CO
2is not released into the atmosphere, but separated from the process gases. The resultant high purity CO
2 is available for utilisation or sequestration.
The remaining calcium oxide is hydrated in a steam slaker at 300°C (CaO + H
2O Ca(OH)
2), and the regenerated calcium hydroxide is fed back into the pellet reactor in step two above.
The specific energy demand varies, depending on the Calciner input energy method and operating temperature. The total specific energy is 1,850 kWh/Tonne of CO