Why recover condensate?

Steam is generated and used to heat a medium or to drive a mechanical piece of equipment like a steam turbine. To heat a medium the steam gives up its energy by exchanging the heat contained in it by condensing against a heat transfer surface. The steam therefore changes state back to water (called condensate). This condensate formed from the steam consuming equipment (and from any distribution areas) should be returned back to the boiler hotwell feedtank. 

  • Condensate is a very valuable part of the steam and condensate cycle which can be re-used in the steam and condensate cycle again.
  • Condensate contains about 25% of the useful energy from the original steam.
  • Condensate recovery saves energy by recycling the heat energy in the condensate, rather than dumping it. This reduces the fuel required by the boiler and therefore saves cost.
  • The heat in the condensate can be used to help heat the water in the boiler hotwell feedtank. As a rule of thumb, every 6 degrees C rise in feedwater temperature achieved by “recovered energy” results in an approximate 1% fuel saving by the boiler.
  • The more condensate that is recovered the less fresh water is required. Therefore condensate return reduces water charges.
  • Condensate is in effect boiler quality treated water. By returning this to the boiler and re-using it, water treatment costs are reduced, as less chemicals are used.
  • If condensate is dumped then effluent charges will likely result.
  • In the UK effluent cannot be discharged above 43 degrees C. Condensate is normally always higher than this in temperature. If condensate is dumped as effluent then it must be cooled to below this level or fines and charges will result.
  • Investing in a condensate return system, or improving an existing one by returning additional condensate from other areas, can result in speedy paybacks. Typically this can be in the region of one to two years.
  • On steam systems which currently have flash steam vented to atmosphere (typically on higher pressure systems), incorporating a flash recovery system as part of the condensate recovery system will result in even more savings.

Therefore it is very important to wherever possible return as much condensate to the boiler hotwell feedtank. Want to calculate how much the savings would be from returning condensate? In the calculators section there is a calculator which just requires you to input the details which are relevant to your site, and you will get the answer.

Posted by Admin on 12/09/2014


Interesting article. The sad thing is that on alot of the systems that I worked on in the past, the engineers did not even know their % condensate return..

Even if condensate is contaminated I have seen systems out there to re-use the heat before dumping.

Big Al - Wed 17 Sep 2014 - 10:58

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