The deaerator removes internal corrosive pipe gases (oxygen, CO2) and heat exchangers that melt in the water supply, and also heats the water supply, and it is a device that keeps the water supply pump (net positive suction head) stable. For onshore plants, the spray and tray type is mainly used, and the spray and scrubber type is mainly used for offshore ships. Donghwa Entec has developed the core technology of the deaerators including the spray, tray, and scrubber, and supplies them. We are still performing R&D for performance improvement.