PROS:

Condensate contains not only water, but also boiler treatment chemicals and the energy transferred during combustion. Condensate, therefore, needs to be returned to the boiler to:

  • Improve energy efficiency
  • Reduce chemical cost
  • Reduce make-up water costs
  • Reduce sewer system disposal costs
  • Meet environmental regulations

Condensate contains 25% of the energy of the steam from which it came (Steam specialist:  Paul Mayoh)

CONS:

  • High total dissolved solids in boiler water increase tube corrosion and/or fouling.
  • Increased TDS in the boiler water causes increased foam production on top of the water.
  • There are two types of water hammer: a steam-flow-driven water hammer and condensate-induced water hammer
  • A steam-flow-driven water hammer is an impact event, where a slug of rapidly moving water strikes a stationary object.
  • A condensate-induced water hammer is the more powerful of the two types. It is a rapid condensation event that occurs when a steam pocket, being totally surrounded by cooler condensate, collapses into a liquid state. Depending on the pressures and temperatures involved, the reduction in volume may be by a factor of several hundred to well over a thousand, and the resulting low-pressure void allows the pressurized surrounding condensate to rush in, resulting in a tremendous collision.
  • Wire-drawing will eventually cut enough of the metal in a valve seat, producing leakage in the system.
  • Dirt is always being created in a steam system. Excessive build-up can cause plugging, corrosion or prevent a valve from closing.