steam question ...

Question for the steam guys :
Pipe, 60mm diameter, contains steam at 8 bar and temperature 145
degrees C. Now cool the pipe to 25 degrees C and drop pressure to 0
bar (gauge).
How much condensate will be drained from the pipe per metre?
My thoughts : Trick question...
There shouldn't be any steam at this pressure since water at 8 bar
will only boil once it reaches about 175 degrees.
Is my thinking correct?
Reply to
Hareti
Loading thread data ...
More of my thinking before I thought it was a trick question ...
The mass of steam = the mass of the water once it's completely condensed, so I started by looking for steam tables that would tell me this. If I could find the density of steam at given pressure and temperature I could work out the mass from the volume of the pipe. Trouble is, steam doesn't appear to exist at this temp and pressure.
Then I got to thinking, given the gas law ([p1v1]/t1 = [p2v2]/t2), you can work out pressure and temperature for a constant volume. So if you start at 8 bar and 145 degrees, and finish at 0 bar and 25 degrees, the gas law should agree. But maybe this gas law only works for one phase and doesn't take into account condensation. Maybe the t can only be sensible, or else the equation doesn't work.
I try to picture a pipe with 8 bar steam in it at 145 degrees C ( which isn't THAT hot ), then cool it to room temperature and open the pipe only to find the contents at atmospheric... must be a trick question....
Reply to
Hareti

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.