Introduction to Condensate Recovery
What is Condensate?
Condensate is the liquid formed when steam passes from the gaseous to the liquid state.
Turning water into steam is a two-stage process. Water must first be heated to its boiling point. This initially provided energy is called 'sensible heat'. Then, it must be heated until it vaporizes. This additional energy is called 'latent heat'. If steam loses its latent heat (i.e., by transferring its latent heat to a product), it reverts back to the liquid state, becoming condensate. Since this condensate still contains a large amount of sensible heat, it is best to reuse it to help conserve energy and resources.
What is Condensate Recovery?
Condensate recovery is a process involving the recovery and reuse of condensate discharged from a steam system to save energy and resources.
In a heating process, once steam has transferred its latent heat to the product being heated, it turns into condensate. Recycling this condensate by returning it to the boiler system is a common form of condensate recovery.
If 1 t/h of steam is input in equipment such as a heat exchanger, the same amount of condensate (1 t/h) is output. Reusing this hot condensate (sensible heat) represents valuable energy savings.
Benefits of Establishing a Condensate Recovery System
Significant amounts of energy and resources can be saved by setting up a system to quickly recover and reuse condensate. Here are some of the benefits of using such a system:
Energy Conservation
As seen above, the amount of sensible heat contained in condensate is equivalent to 20% or 30% of the heat energy contained in the initial steam. By recovering and reusing this condensate, it may be possible to reduce boiler fuel needs by up to 30%!
Additionally, feeding the boiler with high-temperature condensate can improve the boiler firing rate, minimizing energy consumption.
Lower Water-related Costs
As long as any impurities picked up during condensate transport are removed, condensate can be reused as boiler feed water, reducing water treatment and effluent costs.
Environmental Protection
Reducing boiler fuel needs through condensate recovery leads to less air pollution by lowering CO2, NOx and SOx emissions. Reduced water needs also help reduce environmental impact.
The use of condensate recovery lines can also decrease work environment noise by reducing the sound generated by condensate discharge.
Additional Info
Condensate recovery isn't limited to boiler feed water. Recovering condensate from the large vapor clouds that form when condensate is directly released to the atmosphere can be another useful technique. This requires the use of a steam compressor or another steam compressing device and can help provide a safer, more comfortable working environment.
For additional information on the different methods of condensate recovery, visit the next article on Types of Condensate Recovery.
