How Process Control System Works In Deaerator

Read: What is Deaerator? working principle, Types

Working Principle of deaerators
Deaerator operates in very low-pressure steam about 0.5 to 1.5 kg/cm2 with can produce in the process plant. The low steam sources could also be anyone of the following: Extraction from back pressure turbines, Flash steam recovered from Boiler blowdown or letdown steam from high-pressure steam header through the pressure reducing valve. Steam pressure within the deaerator should be maintained to facilitate the removal of dissolved gases from water and also to produce adequate NPSH to the boiler feed pump. Deaerators are commonly put in at high elevation so as to produce enough NPSH within the event of a failure in steam pressure control conjointly. The pressure safety valve is additionally fitted to avoid pressurization of the deaerator because of the malfunctioning of the pressure control valve.

Water Level control

The main sources of raw water to deaerator are Treated water from the water treatment plant and steam condensate from the condensing type turbines. During the stable plant operation, the water balance is maintained and through any upset within the higher than said sources water level fluctuates and control is important. High level and low-level alarms are provided. The low level might lead to starvation of feed water in the pump and High level leads to water entry into the steam header. Thus overflow drain is put in to drain the water if a very high level is reached.

Water level control working of deaerators

Other benefits of Deaerator

Deaerator acts as extra storage that provides a reserve amount of boiler feed water throughout upstream water supply failure for momentary periods commonly for about twenty minutes.

In some of the Plants, Deaerator is additionally used for dosing oxygen-scavenging chemicals like hydrazine or Hydroquinone.

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