Methods and systems for reducing carbon dioxide in combustion flue gases

A combustion system 100 and method of processing a flue gas adapted to remove carbon dioxide from a gas. The combustion system 100 includes an absorber unit 130 including a housing for channeling a combustion flue gas, an ammonia-based liquid reagent channeled within the housing, a membrane contactor (170) coupled within the housing to separate the ammonia based liquid (182) from the flue gas, the membrane contactor comprising a plurality of pores (178) defining gas-liquid interface areas (180), the ammonia-based liquid and the flue gas contacting at the gas-liquid interface areas to separate carbon dioxide from the flue gas by a chemical absorption of CO2 within the ammonia-based liquid to provide a CO2-rich ammonia-based liquid. The system may further comprise a desorber unit 150 coupled to the absorber unit, wherein the desorber unit receives and releases CO2 from the CO2-rich ammonia-based liquid. The membrane contactor comprises a polytetraflouroethylene (PTFE) in hollow fibre membrane form, tube and shell arrangement, planar sheet or spiral wound planar sheet.