High solids flux circulating carbonation reactor
View Patent ↗The present invention relates to a method for capturing carbon dioxide CO 2 by carbonation in a circulating fluidized bed (CFB) carbonation reactor wherein temperature profile is adjusted by recirculation of solid fractions of metal oxide MeO and metal carbonate MeCO 3 to the CFB carbonation reactor. Also a system recirculating the metal oxide MeO and metal carbonate MeCO 3 is provided by the invention.
1. A method for capturing carbon dioxide (CO 2 ) by carbonation in a circulating fluidized bed (CFB) carbonation reactor comprising the steps of:
forwarding a metal oxide (MeO) rich stream to the CFB carbonation reactor;
forwarding a carbon dioxide rich flue gas stream to the CFB carbonation reactor;
capturing the CO 2 present in the flue gas by reacting the CO 2 with metal oxide (MeO), forming metal carbonate (MeCO 3 );
separating the MeCO 3 from the flue gas in a separation device;
collecting a MeCO 3 rich solids stream from the separation device;
subsequently cooling and dividing the MeCO 3 rich solids stream to form at least one or more cooled portions of the MeCO 3 rich solids streams;
adjusting the temperature profile of the CFB carbonation reactor by addition of one or more cooled portions of the MeCO 3 rich solids stream to the CFB carbonation reactor at one or more selected locations to optimize the temperature profile for capturing of the CO 2 , wherein the temperature profile of the CFB carbonation reactor is adjusted by recirculating a first cooled portion of the MeCO 3 rich solids stream to a lower region of the CFB carbonation reactor.
2. The method according to claim 1 , wherein the MeCO 3 rich solids stream is cooled by a fluidized bed heat exchanging device located downstream the CFB carbonation reactor.
3. The method according to claim 1 , wherein the temperature profile of the CFB carbonation reactor temperature is further adjusted by recirculating a second cooled portion of the MeCO 3 rich solids stream to an intermediate region located between the lower region and an upper region of the CFB carbonation reactor.
4. The method according to claim 3 , wherein the temperature profile of the CFB carbonation reactor is further adjusted by recirculating a third cooled portion of the MeCO 3 rich solids stream to the upper region of the CFB carbonation reactor using a device to aid solids transport.
5. The method according to claim 3 , wherein temperature of the second cooled portion of the MeCO 3 rich solids stream is 50° C. to 200° C. below the temperature of the CFB carbonation reactor.
6. The method according to claim 1 , wherein temperature of the two or more cooled portions of the MeCO 3 rich solids stream at least 10° C. below the temperature of the CFB carbonation reactor.
7. The method according to claim 6 , wherein the temperature of the two or more cooled portions of the MeCO 3 rich solids stream is between 10-50° C. below the temperature of the CFB carbonation reactor.
8. The method according to claim 1 , wherein temperature of the two or more cooled portions of the MeCO 3 rich solids stream is at least 200° C. below the temperature of the CFB carbonation reactor.
9. The method according to claim 1 , wherein the one or more locations are selected to ensure optimized temperature profile of the CFB carbonation reactor for capturing of the CO 2 .
10. The method according to claim 1 , wherein mass flow of the two or more cooled portions of the MeCO 3 rich solids stream is adjusted to optimize the temperature profile of the CFB carbonation reactor for capturing of the CO 2 .