Definition - What does Feedwater Heater mean?
A feedwater heater is a type of industrial equipment that acts as a heat exchanger by increasing the temperature of a liquid via thermodynamic contact with an external fluid of higher temperature. Often, the liquid to be treated is water and the external fluid is steam. Feedwater heaters are prone to corrosion due to their constant contact with moisture.
Corrosionpedia explains Feedwater Heater
The operation of a feedwater heater involves the fluid to be treated entering the heater in a saturated state. It is first desaturated and then converted to a vapor or a very hot liquid by heat transfer with an external medium. The product leaves the heater in a superheated or subheated liquid form. The exact state of the product may be manipulated by altering the temperature of the external medium or the heater's design. The mechanism of feedwater heaters is described using refrigeration (or heating cycles). The refrigeration cycle of a heater is unique to the fluid being treated and the heater's design.
Corrosion of feedwater heaters may be prevented by lining them with a thermal barrier coating.