What is Condensate Recovery Factor

Condensate coming out of a steam distribution pipeline or equipment is at a pressure greater than atmospheric pressure and carries surplus sensible heat corresponding to its pressure.

When this condensate is discharged from a high-pressure system to a low pressure system, the temperature at which it can exist as a liquid decreases i.e. the saturation temperature of condensate at high pressures is greater than that at lower pressures.
For example the saturation temperature of condensate at 3barg as seen above is 143.6ºC whereas at atmospheric pressure it is 100ºC.

As a result when the condensate is discharged from a high pressure to a low pressure the excess heat content evaporates to form flash steam. The quantity of flash steam generated depends on the amount of sensible heat that can be held in condensate. In a mixture of condensate and flash steam, although flash steam is only about 10%~15% by mass, it holds 50% of the energy content of condensate.

There are two key sources in the steam circuit, where condensate will be separated out from steam i.e. from drain points on steam pipelines and from process equipment which use steam for heating. Recovering condensate and flash steam from both these sources is critical to maximise the efficiency of the steam system. However, a compilation of our observations across thousands of plants indicates that very few
plants recover all available condensate and flash steam. The chart below highlights the gap we see across different industry sectors between the best and average recovery factor.

Reasons for poor recovery across plants include
▪ Local drainage as a result of bypassing steam traps
▪ Draining of condensate due to issues of condensate contamination
▪ Layout constraints in the plant including distance being an issue
▪ Condensate overflow losses and venting of flash through conventional systems
▪ Poor uptime of steam traps and condensate recovery systems