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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

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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:

Percent Flash Steam of Condensate (%)
Absolute Pressure before the Condensate Trap (kN/m²)	Temperature (^oC)	Absolute Pressure after the Condensate Trap (kN/m²)
Absolute Pressure before the Condensate Trap (kN/m²)	Temperature (^oC)	400	260	170	101.33	65	35
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.