Capture and Re-Use Waste Condensate
According to the DOE, the primary purpose of an effective condensate-recovery system is to use as much of the steam and condensate as possible that remains after process use. Key components include condensate return piping, flash tanks and condensate pumps.
Key inputs include condensate from the end-use system, which includes condensate returned to the generation system and low-pressure steam transmitted to applications that can use it. The low-pressure steam component consists of flash from the condensate receiver (or steam trap) plus blow-through steam that accompanies the condensate.
To improve recovery efficiency, DOE suggests you first identify how much condensate you presently recover and return to the boiler system, then determine if you can increase the amount of condensate that you return. By re-using the condensate, companies can save money by using less energy from their utility company and by using fewer water treatment chemicals.
DOE cautions manufacturers to always ensure that condensate piping is adequately sized so that it can accommodate two-phase flow B liquid and vapor. The vapor portion of the condensate stream is more voluminous than the liquid portion. In general, condensate piping must be sized to handle the flash and blow-through steam rather than just the liquid portion. Condensate piping that is sized for the liquid portion only will be grossly undersized.
Also ensure that your condensate return piping, flanges and valves are insulated properly. And finally, according to the DOE's website, check to see if it is possible to return hot condensate to a flash-recovery system in which you use the flash steam to supplement low-pressure steam needs.
For more tips from DOE's Industrial Technologies program, visit www.oit.doe.gov/bestpractices/.