Boiler water treatment uses chemicals for five jobs: removing the oxygen left in the feedwater, stopping calcium and magnesium from forming scale, keeping the water at the right alkalinity, protecting the condensate lines from acid attack and turning solids into loose sludge that leaves the boiler with the blowdown.
Eurochem S.A. supplies boiler water treatment chemicals for each of these jobs. Ask us which products suit your boiler.
Ask about your boilerThe five chemical groups and what each one does
| Job | How the chemical works | Eurochem products |
|---|---|---|
| Oxygen removal | An oxygen scavenger such as sodium sulphite consumes the dissolved oxygen before it corrodes the boiler. | KEMOX - L, a liquid catalyzed sodium sulphite oxygen scavenger |
| Hardness and scale control | Calcium and magnesium salts form scale. Treatment changes them into suspended sludge instead of scale. | KEM - FOS - L for low-pressure boilers and KEM HARD for hardness reduction |
| Alkalinity control | Keeping the right pH stops the boiler metal from dissolving. Too much alkalinity makes foaming more likely. | ALKALINITY CONTROL |
| Condensate protection | Carbon dioxide carried into the steam condensate system makes it acidic. A neutralizing agent protects the return lines. | CONDENSAMINE |
| Sludge conditioning | Solids that collect in quiet areas of the boiler are kept as loose sludge, which is removed through bottom blowdown. | LIQUID COAGULANT |
The range also includes oxygen scavengers and hydrazine substitutes as separate product groups.
Why oxygen and hardness cause most boiler problems
Dissolved gases such as oxygen and carbon dioxide are aggressive causes of corrosion, and both dissolve easily in water. Hardness comes from calcium and magnesium salts, the same minerals that form scale.
Scale on heat transfer surfaces works like insulation. It reduces heat transfer and can lead to overheating and loss of mechanical strength of the boiler metal.
Chemicals work together with pretreatment and blowdown
- Before the boiler: external treatment removes impurities from the feedwater. Low-pressure boilers can use softened water, where sodium replaces calcium and magnesium, while high-pressure boilers typically need demineralized water.
- Removing gases: a deaerator removes damaging gases when condensate is turned back into feedwater.
- Inside the boiler: the chemicals in the table above deal with what remains.
- Blowdown: part of the boiler water is drained on purpose to remove the impurities that build up, including the sludge.
Water quality varies widely from one region to another, and good drinking water is not necessarily good boiler feedwater.
Cleaning a boiler that already has scale
When scale has already formed, it is removed with an acid descaler. Eurochem S.A. supplies DESCALER, an acidic liquid for heavy oxides and water scale in boilers that is not safe on aluminum and its alloys, and SCALE-OFF-LS-30 for the same use, which is safe on aluminum. After acid cleaning, KEM-NUTRO neutralizes and passivates the surfaces to prevent further oxidation.
See all rust removers and industrial descalers, or the cooling tower water treatment chemicals for open recirculating systems.
Frequently asked questions
What chemicals are used to treat boiler water?
Oxygen scavengers such as sodium sulphite, products that control hardness and scale, alkalinity control products, condensate neutralizers and sludge conditioners. Each one deals with a different part of the boiler water chemistry, alongside pretreatment and blowdown.
Which chemical is used for cleaning a boiler?
Scale that has already formed is removed with an acid descaler, such as DESCALER or SCALE-OFF-LS-30 when aluminum is present. After acid cleaning, an alkaline product such as KEM-NUTRO neutralizes the surfaces and helps prevent further oxidation.
Technical data for every product
Every Eurochem product page includes the Technical Data Sheet, and the Safety Data Sheet is available on request. Send us your question with the form below.
Ask about your boiler
Sources
- Wikipedia, Boiler water. https://en.wikipedia.org/wiki/Boiler_water
- Spirax Sarco, Water Treatment Storage and Blowdown for Steam Boilers. https://www.spiraxsarco.com/learn-about-steam/the-boiler-house/water-treatment-storage-and-blowdown-for-steam-boilers
