This invention relates to a method for desalination of seawater (5, 30) and separation of CO.sub.2 from exhaust (77) from a gas turbine (7). LNG (4) is fed into a heat exchanger (6) in which it receives heat from seawater (5) and heat from steam (27) from an exhaust boiler, and heat from combustion air (3) via a line to an air inlet (33) of said gas turbine (7), for evaporating LNG (4) to gas which is fed to a gas export module (10) and to a fuel gas skid (8) for supplying said gas turbine (7) with fuel. Thus said combustion air (3, 28) at the air inlet to said gas turbine (7) obtains a lowered temperature and increases an efficiency of said gas turbine (7). Said CO.sub.2-rich exhaust gas (77) from said gas turbine (7) is fed into a process unit (17) having an inlet (35a) with a fan (35b) and an outlet for CO.sub.2-reduced exhaust (13). Said cooled seawater from said heat exchanger (6) is fed into said process unit (17) via a coaxial feed pipe (67) for seawater and NH.sub.4OH arranged in said process unit (17). NH.sub.4OH is fed into said coaxial feed pipe (67) and is then mixed with said cooled seawater (30) and released via a series of nozzles in several vertical levels from said feed pipe (67) to said process unit's (17) upwards flowing, rotating exhaust (77). By this device a good mixture of NH.sub.4OH-containing salt water and CO.sub.2-rich exhaust is achieved, for formation of NaHCO.sub.3, NH.sub.4Cl, and fresh water.