Boiler Feed Water Hardness Limit

Feed water treatment to avoid corrosion make up water to steam boilers should be treated with oxygen scavengers to avoid serious corrosion problems.

Boiler feed water hardness limit.

In order for this reaction to take place it is important to maintain a ph at a minimum value of 9 50. Parameters for boiler water. The purity requirements for any feed water depend on how much feed water is used as well as what the particular boiler design pressure heat transfer rate. It is desirable to keep the concentration of phosphates in the water to 30 50 ppm in order for complete reaction of the phosphates with the calcium hardness entering the.

This value will limit the silica content of the steam to 0 25 ppm as a function of selective. These are internal treatment and external treatment. Parameters ph th p al. Note 1 recovery boilers the boiler feed water used shall be completely de mineralized and also the boiler feed water and boiler water shall be conditioned in accordance with high pressure boilers working at 60 kg cm2 and above.

Parameter control ph tds total hardnes ca. 131 the internal treatment is for boiler feed water and external treatment is for make up feed water and the condensate part of the system. Maximum flow velocities in water systems water velocities in pipes and tubes should not exceed certain limits. Deposition from low less than 1 0 ppm hardness boiler feedwater is eliminated with chelant programs and can be reduced by up to 95 by a good polymer phosphate treatment program.

Steam boiler rating and feed water temperature boiler output and feed water. T d s amine sio2 chloride iron fe standard 9 5 10 2 nil 5 8ppm 10 15ppm 15 30ppm 5 10ppm 1 ppm 1 ppm 01ppm. For boiler water ph is maintained between 11 11 8 and that of feed water between 7 9. Parameters for cooling tower.

Internal treatment protects against feed water hardness by preventing. The treatment of boiler water can be put into two parts. A total hardness as c a co 2 mg l max. Iron oxide is of particular concern in today s boiler water treatment programs.

Phosphates are used to react with calcium hardness in the boiler water. Feed water boiler water characteristics as per is 10392 1982 1 feed water parameters upto 20 kg cm2 21 kg cm2 to 39 kg cm2 40 kg cm2 to 59 kg cm2 unit total hardness 10 1 0 0 5 ppm as caco 3 ph value 8 5 9 5 8 5 9 5 8 5 9 5 dissolved oxygen. Some impurities such as hardness iron and silica are of more concern for example than sodium salts. The limits can be relaxed.