Flash Steam Generation - Imperial Units (psig)
When condensate passes steam traps - flash steam is generated.
The amount of flash steam generated depends on 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 condensate traps:
Steam Pressure before the Steam Trap (psig) | Flash Steam generated from Condensate (%) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Condensate Pressure after the Trap (psig) | |||||||||||
| 01) | 2 | 5 | 10 | 15 | 20 | 30 | 40 | 60 | 80 | 100 | |
| 5 | 1.7 | 1 | |||||||||
| 10 | 2.9 | 2.2 | 1.4 | ||||||||
| 15 | 4 | 3.2 | 2.4 | 1.1 | |||||||
| 20 | 4.9 | 4.2 | 3.4 | 2.1 | 1.1 | ||||||
| 30 | 6.5 | 5.8 | 5 | 3.8 | 2.6 | 1.7 | |||||
| 40 | 7.8 | 7.1 | 6.4 | 5.1 | 4 | 3.1 | 1.3 | ||||
| 60 | 10 | 9.3 | 8.6 | 7.3 | 6.3 | 5.4 | 3.6 | 2.2 | |||
| 80 | 11.7 | 11.1 | 10.3 | 9 | 8.1 | 7.1 | 5.5 | 4 | 1.9 | ||
| 100 | 13.3 | 12.6 | 11.8 | 10.6 | 9.7 | 8.8 | 7 | 5.7 | 3.5 | 1.7 | |
| 125 | 14.8 | 14.2 | 13.4 | 12.2 | 11.3 | 10.3 | 8.6 | 7.7 | 5.2 | 3.4 | 1.8 |
| 160 | 16.8 | 16.2 | 15.4 | 14.1 | 13.2 | 12.4 | 10.6 | 9.5 | 7.4 | 5.6 | 4 |
| 200 | 18.6 | 18 | 17.3 | 16.1 | 15.2 | 14.3 | 12.8 | 11.5 | 9.3 | 7.5 | 5.9 |
| 250 | 20.6 | 20 | 19.3 | 18.1 | 17.2 | 16.3 | 17.7 | 13.6 | 11.2 | 9.8 | 8.2 |
| 300 | 22.7 | 21.8 | 21.1 | 19.9 | 19 | 18.2 | 16.7 | 15.4 | 13.4 | 11.8 | 10.1 |
| 350 | 24 | 23.3 | 22.6 | 21.6 | 20.5 | 19.8 | 18.3 | 17.2 | 15.1 | 13.5 | 11.9 |
| 400 | 25.3 | 24.7 | 24 | 22.9 | 22 | 21.1 | 19.7 | 18.5 | 16.5 | 15 | 13.4 |
1) It is common to vent the condensate system to the atmosphere - where the gauge pressure is 0 psig.
- 1 psi (lb/in2) = 6,894.8 Pa (N/m2) = 6.895x10-3 N/mm2 = 6.895x10-2 bar
Example - Generated Flash Steam
A condensate system is vented to the surroundings and the pressure in the condensate return system after the steam traps is therefore 0 psig (atmospheric pressure). The steam pressure before the steam traps is 160 psig.
According the table above 16.8% of the condensate evaporates as flash steam passing the traps.
Note! Without any flash recovery system the energy in the flash steam will be lost to the surroundings.
If you prefer SI units - go here!
Related Topics
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Flash Steam
Flash steam generation - thermodynamic fundamentals, heat loss, energy recovery and more. -
Steam and Condensate
Steam & condensate systems- properties, capacities, pipe sizing, systems configuration and more.
Related Documents
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Condensate Pipes - Flash Steam Generated
Calculate flash steam generation in condensate pipe lines. -
Flash Steam Energy Loss
When flash steam is generated and vented to the surroundings a considerable amount of energy is lost -
Flash Steam Generation - Fundamental Physics
Tutorial to the basic physics behind flash steam generation -
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. -
Saturated Steam - Properties - Imperial Units
Steam table with sensible, latent and total heat, and specific volume at different gauge pressures and temperatures. -
Steam Flash Generation (bar)
The amount of flash steam generated depends on steam pressure and pressure in the condensate lines. -
Steam Trap Selection Guide
Steam trap selection guide - Float & Thermostatic, Inverted Bucket, Bimetal Thermostatic, Impulse and Thermodynamic Disc steam traps. -
Steam Traps - Back Pressure and Capacity
A back pressure in a condensate systems will reduce steam trap capacity -
Steam Traps - Safety Factors
Selection of steam traps and their safety factors.
