Condensor

[zamu2010]

Hi All,
I have a generall question. In process plants, we noramlly use the condensor to extract the heat from the system exhasts. What is criteria for selection if someone should design a condensor on these location? Any limit on the energy saving with these condensors??
Thanks in advace for your help on the issue.
BR
Zamu

 

[duncan8943]

If you're using the energy from the exhaust to heat a process stream then you could be limited by the process stream's maximum temperature or by the amount of heat that economically feasible to remove. Most of the time, start with a 10 F approach.

 

[zamu2010]

Hi Ducan 8943,
Thanks for your reply.
Do you mean with delta T of 10 F, the process of heat recovery would be economical??
My concern is the economical heat removel from the vapour/liquid streams. some times to recover heat you need huge amount of cold medium (to remove heat, Like combined heat and power idea in power plants). Is there any ctiteria to say when it will be feasible to do the heat integration of hot stream in the plant.
Any suggestions???

 

[MJCronin]

banu...

"In process plants, we noramlly use the condensor to extract the heat from the system exhasts"

Yes....if you are condensing steam from a turbine and want to ensure the maximum transfer of energy form the steam into mechanical power. Superheated steam is commonly used in this application.

If you use the steam in order to heat something...use saturated steam...

I do not understand the rest of your question.....

-MJC

 

[rmw]

zamu,

Yes. If you are trying to extract maximum work out of your turbines, you want to design your condensers to have the lowest back pressure possible for your turbines to exhaust into. It is a function of your cooling water source.

Also, steam normally has some non condensables in it and a turbine condenser will have to be designed with a separate section especially designed to remove any non condensables.

Also, if you are reusing the condensate in your boilers, you want as little subcooling of the condensate as possible, as all subcooled condensate ultimately has to have energy added back to it to bring the water back to the boiling temperature in the boiler (or deaerator).

Condensers are heat exchangers, but not all heat exchangers are condensers. Don't be fooled.

MJC, I didn't understand your " yes..." answer at all. What does the use of superheated steam have to do with condenser selection? Please elaborate.

rmw

 

[zamu2010]

Thanks for your replies guys.
I am afraid i could not follow the idea of having lowest back pressure in condensers for turbines.
How is the function of cooling water source??