Steam Boiler Treatment Chemicals

The primary objectives in boiler design, operation and effective treatment include: efficiency in heat transfer, minimisation of energy usage, production of pure steam and safe, reliable operation.

The problems encountered in steam-raising plant can be severe if scale formation and corrosion are allowed to occur. Problems can range from loss of efficiency and reduction of plant life to, at worst, catastrophic failure. It is also necessary to prevent boiler water carryover, where boiler water (including its dissolved solids) is carried into the steam, sludge deposition and foaming.

Both external and internal treatment of the boiler water is used for optimal operation. An effective internal boiler treatment programme involves the addition of chemicals to the feed water, boiler water and steam in order to confer desirable attributes, or to react with traces of undesirable constituents which can remain after external treatment. Typically, oxygen scavengers, dispersants and alkalinity builders are standard. Other products including condensate line corrosion inhibitors and antifoams may also be used.

Oxygen Scavengers

A major cause of corrosion in boilers is dissolved oxygen

Dispersants

A conditioner is required which will react with any residual hardness present in the incoming feed water

Alkalinity Builders

A pH adjuster for steam boilers where there is insufficient alkalinity in the feed water.

Return Line Treatments

Corrosion can also occur in condensate return lines. Corrosion can be caused by oxygen in the steam or carbon dioxide which leads to the production of carbonic acid.

We also have a full catalogue of Multi-Purpose Boiler Treatments which comply with FDA regulations for steam which comes into contact with food

A major cause of corrosion in boilers is dissolved oxygen, particularly in conjunction with low pH (low alkalinity) although excessive alkalinity can also be a factor. Chemical oxygen scavengers are used to eliminate oxygen from the feed water. The main types of oxygen scavenger are shown below:

Product codeCompositionComments
ST669Sulphite based.FDA approved, catalysed sodium metabisulphite.
ST177Sulphite and DEHA based.Dual action corrosion inhibitor for steam raising plant and hot water systems. Generally used in smaller systems.
ST173Tannin Based.FDA approved. Concentrated formulation. Useful for boilers with low feedwater temperature.
ST387Tannin Based.FDA approved. Useful for boilers with low feedwater temperature.
ST166Sodium Erythorbate.For steam raising plant operating up to 40bar. Can be used where the steam comes into contact with food or food products.
ST449Sodium erythorbate and neutralising amine based formulation.For steam raising plant operating up to 40bar. Can be used where the steam comes into contact with food or food products (other than milk and providing the neutralising amine is less than 15ppm in the condensate).
ST176DEHA based formulation.Very concentrated DEHA based formulation.
ST169DEHA based formulation + catalystVery concentrated DEHA based formulation + catalyst.
ST175DEHA based formulation.For steam raising plant and hot water systems including medium pressure hot water systems.
ST681Carbohydrazide based formulationSuitable for use in boilers of any pressure up to and including supercritical (220 bar g)
ST899Concentrated Carbohydrazide based formulationConcentrated formulation. Suitable for use in boilers of any pressure up to and including supercritical (220 bar g)

Scale results from the formation of insoluble calcium and magnesium salts and is seen as a rock like coating on the inside of boiler tubes. A conditioner is required which will react with any residual hardness present in the incoming feed water, and prevent precipitation of scale onto the boiler surface. Phosphate, polymers and chelant treatments are typically used. Sludge conditioners tend to be organic polymers and help to prevent the adherence of suspended solids onto heat transfer surfaces. The polymers combine with precipitates and the resultant electrical charge on the particle surface enables the particles to be dispersed so that they may be removed by blow-down.

Product codeCompositionComments
ST34Polymer and phosphate based formulationFor use as a scale and sludge conditioner for steam boilers preventing scales adhering to the metal surfaces. Use with softened or low hardness waters, FDA approved. Concentrated formulation.
ST1237Polymer, phosphate and caustic based formulationFor use as a scale and sludge conditioner for steam boilers preventing scales adhering to the metal surfaces. Use with softened or low hardness waters, FDA approved. Concentrated formulation. Increases alkalinity.
ST37A blend of polymers and sequestrants.Useful for cleaning scale and sludge from boilers whilst they are on-line. FDA approved.
ST666Polymer and phosphate based formulation.A boiler feedwater treatment for the control of scale. Suitable for low hardness, softened and de-alkalised feedwater.
ST802Polymer and phosphate based formulation.A powdered dispersant and sludge conditioner for steam raising plant. Includes an antifoam.
ST450Polymer and phosphate based formulation.A pH regulator for high pressure steam generation plant. Contains only components approved by the FDA for the treatment of boilers where the steam contacts food.
ST451Phosphate and caustic based formulation.A pH regulator for high pressure steam generation plant. Contains only components approved by the FDA for the treatment of boilers where the steam contacts food.
ST917Phosphate and caustic based formulation.A pH regulator for high pressure steam generation plant. Contains only components approved by the FDA for the treatment of boilers where the steam contacts food.
Product codeCompositionComments
ST24An aqueous solution of sodium hydroxide.A pH adjuster for steam boilers where there is insufficient alkalinity in the feed water. Complies with FDA regulations for steam that comes into contact with food.
ST792An aqueous solution of sodium hydroxide + polymer.A pH adjuster for steam boilers where there is insufficient alkalinity in the feed water. Also contains a polymer dispersant which disperses residual hardness. Complies with FDA regulations.
ST23An aqueous solution of sodium hydroxide.Concentrated pH adjuster for steam boilers where there is insufficient alkalinity in the feed water. Complies with FDA regulations for steam that comes into contact with food.
ST518An aqueous solution of sodium hydroxide.Very concentrated pH adjuster for steam boilers where there is insufficient alkalinity in the feed water. Complies with FDA regulations for steam that comes into contact with food.
ST965An aqueous solution of sodium and potassium hydroxide.Very concentrated formulation. pH adjuster for steam boilers where there is insufficient alkalinity in the feed water.

Corrosion can also occur in condensate return lines. Corrosion can be caused by oxygen in the steam or carbon dioxide which leads to the production of carbonic acid. Oxygen should ideally have been dealt with by the treatment of the feed water but any remaining can be removed using steam volatile oxygen scavengers. Carbon dioxide corrosion can be controlled by pre-treatment techniques or by the addition of steam volatile neutralising and filming amines. Filming amines are generally dosed into the steam lines and form a protective film on the surface of the condensate lines. Neutralising amines enter the condensate lines with the steam and neutralise the carbonic acid thereby raising the pH.

Product codeCompositionComments
ST214Cyclohexylamine based formulation.Condensate line corrosion inhibitor for steam raising plant.
ST216Filming amines and neutralising amines.A combination of filming amines and neutralising amines for the prevention of condensate pipework corrosion.
ST218Filming amine.A filming amine – prevents corrosion of condensate pipework. Should be injected directly into the steam header.
ST219Cyclohexylamine and morpholine based formulation.Condensate line corrosion inhibitor for steam raising plant.
ST222Combination of 2 neutralising amines.Condensate line corrosion inhibitor for steam raising plant.
ST223Mixed amines + DEHACondensate line corrosion inhibitor for steam raising plant. Extends the life of condensate pipework by retarding the rate of ‘grooving’ by acidic condensate. Also protects return lines by scavenging dissolved oxygen.
ST224Combination of 3 neutralising amines.Condensate line corrosion inhibitor for steam raising plant.
ST215Mixed amines + DEHA.Condensate line corrosion inhibitor for steam raising plant. Extends the life of condensate pipework by retarding the rate of ‘grooving’ by acidic condensate. Also protects return lines by scavenging dissolved oxygen.
ST225Cyclohexylamine and morpholine based formulation.More concentrated formulation of BV219 but with differing amine ratios.
ST452Combination of 3 neutralising amines.More concentrated formulation of BV224 but with differing amine ratios.
ST467Non-amine based.A low toxicity condensate line corrosion inhibitor. FDA approved for use in steam raising plant where the steam contacts food. Maximum approved dose rate 20ppm. Must be dosed into steam header.

All the below sulphite based multi-purpose boiler products comply with the FDA regulations for steam that comes into contact with food. The below product formulations differ in their composition in particular in their sulphite and caustic levels. 

Product codeCompositionComments
ST399Catalysed Sulphite, phosphate, polymer, low caustic.A multipurpose sulphite based product for smaller steam boilers. . This product complies with FDA regulations for steam that comes into contact with food.
ST150Catalysed Sulphite, phosphate, polymer, high caustic.A multipurpose sulphite based product for smaller steam boilers. . This product complies with FDA regulations for steam that comes into contact with food.
ST151Catalysed Sulphite, polymer, high caustic.A multipurpose sulphite based product for small steam boilers, low and medium hot water systems or steam generators. . This product complies with FDA regulations for steam that comes into contact with food.
ST805Catalysed Sulphite, phosphate, polymer, high caustic.A multipurpose concentrated sulphite based product for steam raising plant. . This product complies with FDA regulations for steam that comes into contact with food.
ST1001Catalysed Sulphite, phosphate, polymer, high caustic.A multipurpose concentrated sulphite based product for steam raising plant. . This product complies with FDA regulations for steam that comes into contact with food.
ST149High catalysed Sulphite, phosphate, polymer, low caustic.A multipurpose concentrated sulphite based product for steam raising plant. . This product complies with FDA regulations for steam that comes into contact with food.

Low solids multi-purpose ‘one drum’ products.

Product codeCompositionComments
ST1112A blend of polyamines, neutralising amines and polymers.An organic based product which prevents corrosion in boilers fed on softened water, by forming a protective film on metal surfaces. The volatility of the components ensures protection of steam and condensate lines from a single dosing position, as well as the feed and boiler system.
ST1045A blend of polyamines and neutralising amines.An organic based product which prevents corrosion in boilers fed on demineralised water, by forming a protective film on metal surfaces. The volatility of the components ensures protection of steam and condensate lines from a single dosing position, as well as the feed and boiler system.
 
Product codeCompositionComments
ST144Tannin and sodium hydroxide based formulation.A multipurpose product containing an oxygen scavenger with added alkalinity for steam boilers and LPHW. . This product complies with FDA regulations for steam that comes into contact with food.
ST697Tannin and polymeric dispersant based formulation.A multipurpose product containing an oxygen scavenger with dispersants. Ideal for the protection of cold feed systems and for the protection of intermittently operated boiler plant. This product complies with FDA regulations for steam that comes into contact with food.
ST970Tannin, sodium hydroxide and polymer based formulation.A multipurpose product containing an oxygen scavenger with dispersants and caustic alkalinity. Suitable for cold feed systems where dissolved oxygen levels are high. . This product complies with FDA regulations for steam that comes into contact with food.
ST1434Tannin, sodium hydroxide and polymer based formulation.A multipurpose product for smaller boilers containing an oxygen scavenger with dispersants and caustic alkalinity. Suitable for cold feed systems where dissolved oxygen levels are high. . This product complies with FDA regulations for steam that comes into contact with food.
Product codeCompositionComments
ST1Boiler anti-foam. Polyalkyl glycol ether based formulation.An antifoam suitable for steam boilers to prevent foaming and carryover of the boiler water into the steam. Acts as the water steam interface to control foam generation. This product complies with FDA regulations for steam that comes into contact with food.
ST243Alkaline ‘boil-out’ chemical. Sodium hydroxide, low foaming surfactant and polymeric dispersant based formulation.A combination of strong alkalis and surfactants for removing grease and manufacturing debris for new steam boilers before commissioning and being placed into service.
ST74Fuel treatment. Magnesium soap in petroleum distillate based formulation.A fuel additive to improve the combustion of heavy fuel oil and to keep heat transfer surfaces clean.
ST83Resin cleaner Phosphonates and organic acid.A resin cleaner for base exchange softening plant.
ST85Crushed dolomitic limestone for pH correctionEffective acid neutralising product, neutralises acid effluent.
ST501Salt granulesFor regeneration of base exchange softener resins.
Acid Descaling  
ST7828% Hydrochloric acid.For acid descaling.
ST1535Hydrochloric acid 32% + corrosion inhibitorA highly active acid cleaner and descaler. Also includes a corrosion inhibitor to protect bare metal surfaces particularly carbon steel. Removes both calcium and iron deposits.
ST13Aliphatic amine based corrosion inhibitorConfers corrosion inhibition during descaling with Hydrochloric acid
ST42Sulphamic acid crystalsMild acid descaler. Crystals. Dissolve in water to produce a 5 – 10% solution.
ST43Sulphamic acid crystals + amine based corrosion inhibitor.A highly active combination of acid cleaner and descaler with corrosion inhibitor to protect carbon steel, copper and brass against acid attacks. It can be used on a wide variety of metals including stainless steel. Dissolve crystals in water to produce a 5 – 10% solution then add inhibitor as instructed on product data sheet.
ST231Sulphamic acid solutionReady to use Sulphamic acid descaler.
ST8Mineral oil based antifoamGives foam control during descaling operations.