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Condensate load to determine capacity of steam trap

Today we discuss how to calculate condensate load in order to determine the required capacity of a steam trap. The condensate load is directly related to the amount of energy transferred from the steam to the process. Process plants use steam as a energy distribution medium. As the steam loses its energy, it turns into condensate. There are 2 scenarios which we may wish to consider:

1) Start up of process from cold
2) Continuous operation in a steady state

Calculate Condensate load of process equipment

First, we have to determine the required amount of heat transferred from the steam to the process. There are 2 scenarios which we may wish to consider:

1) Start up of process from cold
2) Continuous operation in a steady state
Starting a process from cold
Energy from steam is needed to heat up the cold process fluid. The amount of condensate formed is equivalent to the amount of energy which is transferred from the steam to the fluid. From this theory, we can deduce the following formula:



Where:
Q : Condensate Load (kg/h)
W = Weight of process fluid
T = Saturated steam temperature
t = Initial temperature of process medium
m = time needed to heat up system (minutes)
L = Latent heat of steam

Condensate Load at Steady State



Where:
G : Condensate load generated (g/h)
Ts : Saturated steam temperature
Ta : Ambient temperature
Dsi : Main pipe insulation’s inner diameter (m)
Dso: Main pipe insulation’s outer diameter (m)
a : Overall heat transfer coefficient
Ais : Thermal conductivity of insulation
L : length of main pipe (m)
v : latent heat of steam (kJ/kg)

Conclusion

Steam is usually used in many industries as an energy transfer medium. As steam loses its energy, it turns into condensate. We can calculate condensate load by calculating the amount of energy transfer, and relating the energy to the condensate load using the latent heat of vaporization of steam.