As shown in figure ,The typical spray-type deaerator is a horizontal vessel which has a preheating section (E) and a deaeration section (F). The two sections are separated by a baffle (C). Low-pressure steam enters the vessel through a sparger in he bottom of the vessel.
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| A schematic diagram of a typical spray-type deaerator |
The boiler feedwater is sprayed into section (E) where it is preheated by the rising steam from the sparger. The purpose of the feedwater spray nozzle (A) and the preheat section is to heat the boiler feedwater to its saturation temperature to facilitate stripping out the dissolved gases in the following deaeration section.
The preheated feedwater then flows into the dearation section (F) , where it is deaerated by the steam rising from the sparger system. The gases stripped out of the water exit via the vent at the top of the vessel. Again , some designs may include a vent condenser to trap and recover any water entrained in the vented gas. Also again , the vent line usually includes a valve and just enough steam is allowed to escape with the vented gases to provide a small and visible telltale plume of steam.
The deaerated boiler feedwater is pumped from the bottom of the vessel to the steam generating boiler system.
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