Deaerator Level Control loop (for super critical power plants)


Thread Starter


Dear Friends,

I am in the process of finalizing Deaerator level control loop which uses 3-element control philosophy. 3-elements are listed here.
1) Deaerator level
2) Feedwater flow to boiler
3) Condensate flow to deaerator

While designing this control loop, I have also found that there are also other variable inputs to deaerator (like heater drain flow and deaerator pegging steam from turbine extraction). These parameters are also varying with turbine load.

How to take care of these things while designing control loop.

Whether we should do deaerator mass balancing ? or we should take only feed forward action on boiled feedwater flow ?

Can we consider derivative action on feedwater flow ?

I request you to advise me on this topic. I also request you to share document if you have.

My e-mail IDs are agdsnl [at] and ankur13780 [at]

Best regards

Ananda kannan

Dear Ankur,

Deaerator level settings: -

HHL - Turbine Bleed steam motorised valve close
HL - Deaerator Over flow line open
LL - Emergency makeup water line open
LLL - BFP trip

Deaerator is also called as FWST, it is an equipment storing of HP drains, CBD vent, BFP leak off line,,it will increase the mass flow on deaerator on abnormal condition.

For controlling the deaerator level, the above logics shall be used.