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How to Size a Condensate Storage Tank

Industrial steam systems utilize heated water that has been changed into a vapor state. The heat input into the water is a combination of sensible heat and latent heat. When the temperature of the steam drops below the corresponding boiling point of the water, the steam condenses and gives up its latent heat. The liquid condensate retains the sensible heat. Efficient industrial processes reclaim the condensate that is stored in condensate storage tanks. The amount of condensate produced in a process is required to size the storage tank.

Things You'll Need

Pen
Paper
Calculator

Instructions

- 1
  Determine the pressure and corresponding temperature of saturated steam in an industrial process. For instance, saturated steam can be 375 psia (pounds per square inch absolute), which has a corresponding equilibrium temperature of 438 degrees F. This steam has a corresponding latent heat of 787 btu/lb. If the mass flow of the steam is 1,000 lbs. per hour, the total heat available per hour is 787,000 btu (British thermal units).
- 2
  Determine the total heat that is removed from the process during the steam flow. For example, assume a vessel's jacket heating system removes 50,000 btu/hour to carry out a chemical reaction. Therefore, only 6.4 percent of the total available heat is taken out (50,000 btu/787,000 btu).
- 3
  Calculate the total condensate flow based on the required heat load from the chemical process reactor. This measurement is determined by dividing the total heat removed by the system by the latent heat contained in the steam. The calculation is 50,000/787, which is 63.5 lb./hour of liquid condensate.
- 4
  Convert the mass flow rate of the condensate into gallons (volumetric flow rate), which can be used to size the condensate storage tank. This conversion is completed by dividing the mass flow rate by the water density at the corresponding pressure and temperature. This value can be found in the steam tables. The volumetric flow rate is 63.5 lb./hour divided by 6.94 lb./gallon for a value of 9.14 gallons per hour. Therefore, if a standard storage tank must hold condensate for at least 24 hours, the tank must be have a 219-gallon capacity (24 x 9.14).

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