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.
