When condensate leaves the steam traps - flash steam is generated. Amount of flash steam generated at different pressures - kN/m2.
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 table below indicates the ratio of flash steam generated at different pressures before and after the condensate trap.
A condensate system is vented to the surroundings and the pressure in the condensate system after the condensate traps is 101.33 kN/m2. The absolute steam pressure before the condensate trap is 1150 kN/m2.
According the table above 16.5% of the condensate will evaporate as flash steam after the trap.
Note! Without any flash recovery system the energy in the flash steam will be lost to the surroundings.