Boiler Water Treatment
The water used for boilers usually
contains various substances such as suspended solids, dissolved solids
and gases. When used directly such raw water results in problems such as
scale, corrosion, carryover, etc. in the boiler and accessory
equipment. In low pressure boilers usually there are problems of
hardness and silica scale and corrosion due to dissolved oxygen
throughout the system and corrosion due to carbon-dioxide in the
condensate line. In medium and high pressure boilers, metal oxides are
deposited on the heating surface, corrosion of accessory and scale
problem in the superheater and turbines, etc.
Deposits directly reduce heat transfer,
causing higher fuel consumption, high metal temperatures and eventually
failures. Corrosion not only results in failure at the point of attack,
but also produces serious levels of metal oxide contamination, which in
turn may cause deposits elsewhere. Carryover results in superheater
turbine and condensate system deposits, corrosion and/or erosion
problems.
Therefore the three main objectives of a boiler water treatment program are to:
- Prevent formation of deposits
- Reduce corrosion of metals
- Prevent boiler water carryover
Boiler Compounds
Boiler compounds have two functions: preventing
scale formation and adjusting pH of boiler water to inhibit corrosion.
Treatment with phosphate based boiler compoundsPhosphate
base boiler compounds contain Phosphate and alkali agents. Both these
compounds prevent scale formation by reacting with hardness components
(Ca&Mg) and converting them into suspensible substances and by
keeping silica substances water soluble.
Treatment with non-phosphate based boiler compounds includes polymers and chelating agents.
Oxygen ScavengersOxygen
scavengers viz sodium sulfite, Hydrazine, etc remove dissolved oxygen
in water by a reduction reaction. CAWTL�s patented product Mekor 70
passivates metal surfaces through the formation of magnetite and cuprous
oxide films, minimization of iron and copper deposits in the boiler and
ability to provide corrosion protection to after boiler sections of
the system.
Corrosion protection in boilers is achieved by neutralizing
and filming amines. Neutralizing amines inhibit corrosion by controlling
the condensate pH. Filming amines form a water repellent film on metal
surface which prevents direct contact with the corrosive substances like
oxygen and carbon-dioxide.
Oxygen Scavengers
Kem BLR 10
Kem BLR 100
Mekor 70
Amerzine 35
Steam condensate corrosion inhibitor
Kem BLR 17
Kem BLR 32
Amercor series
Mekor 70
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