Flash Steam Generation (bar)

When condensate leaves the steam traps - flash steam is generated. Table indicating amount of flash steam generated at different pressures - bar

The amount of flash steam generated depend on the steam pressure - the pressure in the condensate before it leaves the condensate trap - and the condensate pressure after the trap - the pressure in the condensate return pipe lines.

The diagram and table below indicates the ratio of flash steam generated at different pressures before and after the condensate trap.

condensate flash steam generation diagram bar

Percent Flash Steam of Condensate (%)
Steam Gauge Pressure
(bar)
Condensate Gauge Pressure (bar)
01) 0.5 1 1.5 2 2.5 3
0 0.0
1 3.8 1.7 0.0
2 6.3 4.2 2.6 1.2 0.0
3 8.3 6.2 4.5 3.2 2.0 0.8 0.0
4 9.8 7.7 6.1 4.8 3.6 2.4 1.7
5 11.2 9.1 7.5 6.2 5.0 3.8 3.1
6 12.3 10.3 8.7 7.4 6.3 5.0 4.3
7 13.4 11.4 9.8 8.5 7.4 6.2 5.4
8 14.4 12.3 10.8 9.5 8.4 7.2 6.5
9 15.2 13.2 11.7 10.4 9.3 8.1 7.4
10 16.1 14.1 12.5 11.3 10.1 9.0 8.3
11 16.8 14.8 13.3 12.0 10.9 9.8 9.1
12 17.5 15.6 14.1 12.8 11.7 10.5 9.8
13 18.2 16.3 14.8 13.5 12.4 11.2 10.6
14 18.9 16.9 15.4 14.2 13.1 11.9 11.2
15 19.5 17.6 16.1 14.8 13.7 12.6 11.9

1) It is common to vent the condensate system to the atmosphere - where the gauge pressure is 0 bar.

  • 1 bar = 105 Pa (N/m2) = 10.197 kp/m2 = 10.20 m H2O = 0.9869 atm = 14.50 psi (lbf/in2)

Example - Generated Flash Steam

A condensate system is vented to the surroundings and the pressure in the condensate system after the condensate traps is 0 bar gauge. The absolute steam pressure before the condensate trap is 10 bar gauge.

According the table above 16.1% of the condensate will evaporate as flash steam after the trap.

Note! Without a flash recovery system the energy in the flash steam will be lost to the surroundings.

If you prefer Imperial units - go here !

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