Steam is simply water that has boiled and changed states. The heat input into water is kept in the steam as total heat that is latent heat and sensible heat. As steam condenses, it gives up its latent heat and the liquid condensate retains the sensible heat. Industrial processes that use steam in heating systems must also capture the condensate to maintain a high efficiency. Therefore, the amount of condensate produced per amount of steam is a useful metric in designing and evaluating heating systems.

Determine the pressure and associated temperature of saturated steam in a heating system. For instance, steam can be assumed to be 350 psia (pounds per square inch absolute), which has a temperature of 432 degrees Fahrenheit. This steam has a corresponding latent heat of 794 btu/lb. If the steam flow is 1,000 pounds per hour, then the total heat input per hour is 794,000 btu.

Determine the process heat that is removed from the steam flow. For instance, assume a vessel’s heating system removes 30,000 btu/hr to perform a reaction. This means that only 3.8 percent of the total available heat is taken out.

Calculate the total condensed liquid flow based on the heat load from the process reactor. This is determined by dividing the total heat removed by the system by the latent heat contained in the steam. The calculation is 30,000 / 794, which is 37.8 lb/hr of liquid condensate.