Water treatment in boilers

Water treatment in boilers

Water treatment in Boiler is a type of industrial water treatment focused on removal or chemical modification of substances potentially damaging to the boiler. Varying types of treatment are used at different locations to avoid scale, corrosion, or foaming.External treatment of raw water supplies intended for use within a boiler is focused on removal of impurities before they reach the boiler. Internal treatment within the boiler is focused on limiting the tendency of water to dissolve the boiler, and maintaining impurities in forms least likely to cause trouble before they can be removed from the boiler in boiler blow-down.

There are two general approaches to conditioning sludge inside a boiler: by coagulation or dispersion. When the total amount of sludge is high (as the result of high feed-water hardness) it is better to coagulate the sludge to form large flocculent particles. This can be removed by blow-down. The coagulation can be obtained by careful adjustment of the amounts of alkalis, phosphates and organics used for treatment, based on the fee-water analysis. When the amount of sludge is not high (low feed water hardness) it is preferable to use a higher percentage of phosphates in the treatment. Phosphates form separated sludge particles. A higher percentage of organic sludge dispersants is used in the treatment to keep the sludge particles dispersed throughout the boiler water.

During the conditioning process, which is an essential complement to the water treatment program, specific doses of conditioning products are added to the water. The commonly used products include:

1.Phosphates-dispersants, polyphosphates-dispersants: reacting with the alkalinity of boiler water, these products neutralize the hardness of water by forming tricalcium phosphate, and insoluble compound that can be disposed and blow down on a continuous basis or periodically through the bottom of the boiler.
2.Natural and synthetic dispersants: increase the dispersive...

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