Desuperheater Installation

[sk10009]

Dear Friends.

What is the purpose of desuperheater installed in the HP steam lines behind steam drum of power boiler?

I guess it's letting steam down.
Is it right?

Thanks.

 

[davefitz]

A drum type boiler controls the final steam temperature primarily via the use of a spray water attemporator. It is normally installed midway thru the superheaters, and will operate at a near steady state when the boiler is at a fixed load, fixed excess air, fixed burner row in service, and fixed operating pressure.The final steam temperature can also be changed by modifying the above listed fixed items or temporarily by use of wall blowers or sootblowers.

refer to standard texts such as B+W "Steam" for the general design philosophy for these items.

 

[EngAbdelkader]

Dave has already answered your question,
I would add to your own sentence "I guess it's letting steam down.." "the right amount" I mean if you're producing superheated steam it's not to lower it down the saturation temperature!
the de-super heater is mainly installed to control the temperature/pressure of the superheated steam produced.

The superheated steam produced is generally a bit hotter than needed, that's why we regulate (divert) a certain amount (flow)to this equipment (which is open to atmosphere) if I am not wrong it looks like a small drum in the top of the boiler structure from where you see in normal operations, steam going out.

Sorry for my long speech.
kader