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Flash Steam Generation - SI-units

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.

Flash Steam Generation from Condensate vs. Steam Pressure - SI-units
Absolute Pressure before the condensate trap
Percent Flash Steam of Condensate (%)
Absolute Pressure after the condensate trap (kN/m2)
1500 198.3 11.3 14.0 16.4 18.9 20.4 23.2
1150 186.0 8.7 11.5 13.9 16.5 18.4 20.9
800 170.4 5.5 8.2 10.8 13.4 15.4 17.9
650 162.4 3.7 6.5 9.1 11.8 13.7 16.3
500 151.8 1.6 4.6 7.1 9.8 11.8 14.4
400 143.6 3.0 5.5 8.3 10.3 12.9
260 128.7 2.6 5.4 7.5 10.2
170 115.2 2.8 5.0 7.7
101.33 100 2.2 4.9

Example - Generated Flash Steam

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.

Related Topics

  • Flash Steam

    Generation of flash steam in steam and condensate systems. Thermodynamic fundamentals, heat loss, energy recovery and more.
  • Steam and Condensate

    Design of steam & condensate systems with properties, capacities, sizing of pipe lines, system configuration and more.

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