Why do I need boiler water treatment?
Boiler water treatment is necessary to protect against the problems that can occur in your boiler systems; carryover, corrosion and scale deposits. Preventing these problems ensures the efficiency of your boiler operation and the maximum plant life for your boiler system.
Why is steam needed?
Processes that are temperature dependant may require an elevated temperature to complete the process so that the correct product or quality can be produced.
Why is steam used for carrying heat?
Water is generally readily available, relatively inexpensive, and easily handled. Water also has a large carrying capacity as it requires 970 BTU to change 0.454 kg of water from boiling point to steam. This energy is then stored in steam and when the steam condenses this energy is released.
At what temperature does water boil?
At atmospheric pressure water boils at 100 degrees C. As the pressure increases so does the boiling point of water.
Is all water suitable for use in boilers?
All naturally occurring water has impurities, and as impurities can cause boiler problems, the type of water used should be carefully considered.
What sort of impurities does water contain and what potential problems can they create?
Water contains impurities which can contribute to solids and scale formation as well as foaming. Minerals such as calcium, magnesium, silica and iron compounds can contribute to scale formation, which reduces the heat transfer capacity of the boiler. Mechanical failure of the boiler tube that the scale is attached to, due to over heating may result. Calcium and magnesium carbonates and sulphates can also carry hardness salts. Dissolved gases can cause problems not only in the boiler steam space as they flash off, but also throughout the boiler system where they can cause corrosion problems.
How pure does feedwater need to be?
This depends on the quantity and impurities. It also depends on: (a) How much feedwater is needed compared to condensate returned, and (b) The boiler design.
What is pre-treatment and why is it used?
Pre-treatment or external treatment is used to reduce or remove impurities that are too high to be tolerated by the boiler system. The pre-treatment systems used may include the following, de-aerator, softener, de-mineraliser, reverse osmosis or evaporation.
What causes boiler corrosion and how can it be prevented?
Boiler corrosion is typically caused by dissolved oxygen and carbon dioxide, excessively high pH conditions and specific chemical corrodents. Corrosion can be prevented by pre-treating the feedwater to reduce/eliminate oxygen and carbon dioxide, maintaining proper boiler water caustic levels and not running excessive amounts of chelant residuals in the boiler.
What causes boiler scale deposits and how can it be prevented?
Scaling occurs when hardness is precipitated out on hot boiler surfaces. Most scaling can be prevented by using the correct water treatment programme including proper pre-treatment to reduce mineral salts entering the boiler and boiler blow down control.