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OwnerJuan Carlos ABANADES GARCÍA, Borja ARIAS ROZADA +1inventors
InventorsJuan Carlos ABANADES GARCÍA, Borja ARIAS ROZADA, José Ramón FERNANDEZ GARCíA
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This invention discloses a calcination process to produce high purity CO2 from solids containing CaCO3 which operates cyclically and continuously on the solids, arranged in a packed or a moving bed, wherein each cycle comprises a first step where the combustion of a fuel in the bed of solids containing CaCO3 heats them up to an average temperature of between 800-950° C. and a second step wherein a CO2 partial pressure swing is applied to extract pure CO2 from the solids containing CaCO3 by feeding steam to the bed. Said combustion can be carried out directly with air, oxygen enriched air or O2/CO2 mixtures when the process is applied to the calcination of a continuous flow of limestone in a moving bed shaft kiln. The process is also applied to calcine CaCO3 formed in reversible calcium looping processes comprising a carbonation reaction step to form CaCO3 from CaO.
Process to recover in high purity form CO2 (7) after separating it from steam (100), the CO2 being released from the calcination of solids containing CaCO3, with said solids being preheated to a temperature between 650-800° C. and arranged in a thermally insulated vessel (1), wherein the process is characterized by the continuous repetition, at least twice, of a sequence of at least the following consecutive steps:
(5) with a fourth solid valve during the first operating period lasting between 5-20 min where fuel (8) is burned within the calcination zone in a staged mode, with the air or other comburent mix (9) being preheated by the CaO (5) and the limestone (4) being preheated with the combustion flue gases flowing from the calcination zone, and means configured to seal the gas entries/outlets and valves for solids during the second operating period lasting between 5-20 minutes except a gas inlet configured to feed steam (100) to the bottom of the calcination zone and a gas outlet configured to extract a product gas containing pure CO2 (7) and steam (100).
Dependencies are inferred from the claim text.