Posted by Mike Hinz on December 19, 1999 at 18:08:43:
In Reply to: Deaeration posted by Lonnie Roberts on December 01, 1999 at 11:56:44:
by heating and either atomizing the water through spraying or by running the water over trays. The idea is to expose as much surface of the heated water as possible to the air so that it will release the trapped gases. Water at 50 F. may contain up to 8 millileters of gas per liter. As the water is heated it is less able to hold this gas.
Deaerators, sometimes referred to as open feedwater heaters, are designed to carry off dissolved oxygen by venting steam. In these systems, a little steam is constantly being vented to the atmosphere, carrying with it the released gases. Oxygen removal efficency depends upon the proper temperature being maintained in the heater, usually 220-230 F, which means keeping a pressure of about 10 psi, depending upon the elevation of the plant.
Any boiler dealer can recommend deaeration equipment.
Oxygen can also be removed, of course, chemically, via sodium sulfite.