Patent ID: 7951353

Claim:
A continuous process for contacting a liquid reagent sequentially with a process gas and a second gas comprising the steps of, (a) introducing a process gas into a downstream mass transfer zone containing a liquid reagent, where the downstream mass transfer zone is in fluid communication with a second downcomer and a downstream downcomer; (b) removing liquid reagent from the downstream downcomer and circulating the removed liquid reagent to an upstream mass transfer zone that is in fluid communication with a first downcomer, where a first flow rate of a second gas is introduced into and mixes with the liquid reagent in the upstream mass transfer zone; (c) introducing at a second flow rate a third gas into the first downcomer where it mixes with the liquid reagent flowing from the upstream mass transfer zone; and (d) allowing the liquid reagent from the first downcomer to flow into a intermediate mass transfer zone that is in fluid communication with the second downcomer, wherein flow of the liquid reagent from the upstream mass transfer zone to the intermediate mass transfer zone is controlled by varying the second flow rate of the third gas introduced into the first downcomer.