Applied chemistry

1. Internal water treatment
Internal treatment is the conditioning of impurities within the boiler system.
Its purposeis to properly react with water hardness, condition sludge, scavenger
oxygen etc.
Examples of internal treatment include following;
METHODS:
 Use of Chelating Agents:
Chelates are prime additives in a solubilizing water treatment program. Chelates
have the ability to complex many cation.
Use: They prevent formation of scales. They control heavy metals.
Example: EDTA, NTA, Porphine
 Use of Dispersant:
The chemicals that are used to condition boiler water treatment called Dispersants.
Use: Dispersant keep the sludge particles dispersed throughout the treatment.
Examples:Acryclic acid polymer is sludge dispersant.
 Use of Precipitants:
Precipitants are chemicals that when added react with dissolved minerals in the
water to producea relatively insoluble reaction product.
Use: Precipitants used in reducing dissolved hardness, alkalinity. They also used to
precipitates the Ca & Mg as non adherent sludge in water treatment.
Example: Most common precipitants is lime sodatreatment.
 Use of Inhibitors:
Inhibitors are a substancewhich slows down or prevents a particular chemical
reaction or other process.

2. Use: Inhibitors act as barrier between metal surface & acid. They do not allow acid
to attack metal surface.Inhibitors are used to prevent corrosion.
Examples: Volatile neutralizing Amines i.e Morph line , cyclohexyl amine &
filming inhibitors.
 Use of Softeners:
Softeners are substancethat softens hard water by removing certain minerals.
Use: They react with Ca & Mg compounds in water to soften the water.
Example: Sodaash, Caustic soda, sodium phosphate.
 Use of coagulants:
Coagulant is an inorganic or organic substancethat initiates or aids a congealing
process during water treatment.
Use: coagulants are used for removal of organic components. Scale formation can
be reduced by using these agents.
Examples: Ferric Sulphate , Ferric Chloride, Alum, Sodium Aluminate.
 Reactionofdissolved Oxygen:
Dissolved oxygen is reduced completely by the addition of certain chemicals called
oxygen scavangers, like by the application of hydrazine, sodium sulfite, sodium
bisulphite and hydroquinone. Mostly hydrazine is used in high pressure boiler.
 PH adjustment:
Ammonia is commonly used cheaper material to maintain pH in boiler water. Soda
ash (sodium carbonate) and sodium hydroxide raise the pH of water to near neutral
when injected into a water system. The pH value of water may need to be adjusted
during treatment to facilitate the removal of iron and manganese.