Boilers 161

Deaerator Vent Plume By James McDonald, PE, CWT Originally Published: CSTN – November/December 2003

How big should a deaerator vent plume be to achieve proper deaeration in a deaerator? The ultimate answer to this question is whatever size plume it takes to remove oxygen down to design parameters without sulfite addition (e.g., 7 ppb). Reading various literature on the subject gives a recommended plume size of 15 to 33 inches of actively moving plume. An average of these recommendations is 24 inches. What is meant by actively moving plume? This does not include the wisp of steam that forms as the vented gases escape to the atmosphere. It includes the vented gases leaving the vent piping up to the point that the wind starts to bend the flow. You may have to look at the steam plume for a minute before you get an accurate feel for where this point is. Also, remember that the height of the steam plume will fluctuate some as the system takes on makeup water and the load changes.