Desuperheat of steam

[Ndimo]

I would like to know, what do you think about using a to desuperheat a steam, a condensate which is at a higher temperature and higher pressure than that steam ?
B barry

 

[rmw]

The idea of desuperheating steam is to cool it from an elevated temperature to a lower one. If your condensate is at a higher temperature than the steam it is supposed to cool, it won't happen. Where would be the driving force for the heat transfer to take place in order to cool the steam to be desuperheated.

The pressure of the condensate is irrelevant to your question. Any condensate used in a desuperheating application would have to be at a higher pressure than the steam to be desuperheated in order to get it into the pipe containing the superheated steam.

If you are going to use this condensate as your desuperheating medium, you are going to have to cool it down somehow.

rmw

 

[DickRussell]

If you take the higher pressure, higher temperature condensate and just flash it to the pressure of the steam, it will flash to an equilibrium mix of saturated steam and water; the flashing will autorefrigerate the mixture down to the saturation temperature. The amount of water left depends on the upstream enthalpy (temperature). If this flashing were to occur into a superheated steam, the superheat would come out as further evaporation of the remaining water from the flash. So the concept would work, but it would take that much more condensate to do the desuperheating than if cooler condensate were used.