condensate temperature

[kszyho100]

Hi

I am designing a condensate pipeline. I have a problem how to determine condensate temperature.
The condensate pipeline is about 110 m long. Dividied in to two section in a building and outside. The pressure before steam traps is 6 bar. Behind the steam traps I lift the pipeline by 5 m. Then with a constant fall
to a tank with atmospheric pressure.
The outdoor section will be run in preinsulated pipes of max. working temperature 140C. I wonder if it's enough.

Kris

 

[mk3223]

The condensate after the trap needs a pressure of about 0.5 bar to push condensate over 5m high pipe. And, the temperature of the condensate tank at atmospheric pressure can be at 100C.
IMO, the condensate should be cooled down as soon as possible and to keep the tank temperature below boiling. And, the pipe can be insulated for the personal protection only.

 

[ione]

You have to calculate the back pressure on your condensate line (0.5 bar for height difference + pressure drop due to friction from the steam trap to the tank + pressure drop due to fittings). Then use steam tables to evaluate saturated liquid temperature. Please note when sizing condensate line you’re going to have a two-phase fluid as part of the condensate will turn into flash steam.

 

[kszyho100]

Static head 0,5 bar,
friction loss 0,4 bar
all togheter about 1 bar loss

So for 1 barg I have temperature 120C.

 

[KevinNZ]

If your traps have a by-pas you could pass a lot of steam in the condensate line. You need to calculated the pressure drop along the line in that case.

Some design codes require drain (condensate) lines to be designed for the upstream conditions

 

[kszyho100]

I expect by-passes on traps so I specifed condensate pipes for 180C.

 

[Rspain]

Hi,

Don't forget the pressure drop on the steam traps.

Isometric sketch possible?

BR,
RSpain

 

[kszyho100]

I remember about pressure drop on steam traps. I don't have isometric drawing.