Boiler Water Chemical Treatment – HydroChemie

Boiler Water Chemical Treatment

Oxygen Scavengers

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 code	Composition	Comments
HC699	Sulphite based.	FDA approved, catalysed sodium metabisulphite.
HC177	Sulphite and DEHA based.	Dual action corrosion inhibitor for steam raising plant and hot water systems. Generally used in smaller systems.
HC173	Tannin Based.	FDA approved. Concentrated formulation. Useful for boilers with low feedwater temperature.
HC166	Sodium Erythorbate.	For steam raising plant operating up to 40bar. Can be used where the steam comes into contact with food or food products.
HC449	Sodium 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).
HC176	DEHA based formulation.	Very concentrated DEHA based formulation.
HC175	DEHA based formulation.	For steam raising plant and hot water systems including medium pressure hot water systems.
HC681	Carbohydrazide based formulation	Suitable for use in boilers of any pressure up to and including supercritical (220 bar g)

Dispersants

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 code	Composition	Comments
HC34	Polymer and phosphate based formulation	For 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.
HC1099	Polymer, phosphate and caustic based formulation	For 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.
HC37	A blend of polymers and sequestrants.	Useful for cleaning scale and sludge from boilers whilst they are on-line. FDA approved.
HC451	Phosphate 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.
HC917	Phosphate 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.

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. 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 code	Composition	Comments
HC216	Filming amines and neutralising amines.	A combination of filming amines and neutralising amines for the prevention of condensate pipework corrosion.
HC219	Cyclohexylamine and morpholine based formulation.	Condensate line corrosion inhibitor for steam raising plant.
HC467	Non-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.
HC1534	Cyclohexylamine, Morpholine and Diethylaminoethanol	Condensate line corrosion inhibitor which will extend the life of pipework by 'retarding' the rate of grooving.
HC1705	Diethylaminoethanol	A simple to use, cost effective neutralising return line treatment.

Alkalinity Builders

Product code	Composition	Comments
HC24	An 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.
HC792	An 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.
HC23	An 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.
HC518	An 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.
HC965	An aqueous solution of sodium and potassium hydroxide.	Very concentrated formulation. pH adjuster for steam boilers where there is insufficient alkalinity in the feed water.

Multipurpose Chemica

Product code	Composition	Comments
HC144	Tannin 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.
HC970	Tannin, 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.
HC1434	Tannin, 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.

Polyamines- File Forming Amines

Low solids multi-purpose ‘one drum’ products.

Product code	Composition	Comments
HC1112	A 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.
HC1045	A 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.

Specialist Products

Product code	Composition	Comments
HC1	Boiler 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.
HC243	Alkaline ‘boil-out’ chemical. Sodium hydroxide, low foaming surfactant and polymeric dispersant based formulation.	For use as a scale and sludge conditioneA combination of strong alkalis and surfactants for removing grease and manufacturing debris for new steam boilers before commissioning and being placed into service. r for steam boilers preventing scales adhering to the metal surfaces. Use with softened or low hardness waters, FDA approved. Concentrated formulation. Increases alkalinity.
HC83	Resin cleaner Phosphonates and organic acid.	A resin cleaner for base exchange softening plant.
HC501	Salt granules	For regeneration of base exchange softener resins.