Boiler Feed Water Hardness Limit

Parameters for boiler water.

Boiler feed water hardness limit. Feed water purity is a matter both of quantity of impurities and nature of impurities. 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. 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. The limits can be relaxed.

Effects if either of the values increases water will accordingly become acidic or alkaline leading to detrimental effects caused due to acidic attack or caustic embrittlement. This value will limit the silica content of the steam to 0 25 ppm as a function of selective. For boiler water ph is maintained between 11 11 8 and that of feed water between 7 9. Parameter control ph tds total hardnes ca.

Steam boiler rating and feed water temperature boiler output and feed 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. Phosphates are used to react with calcium hardness in the boiler water. 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.

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. 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. 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. In order for this reaction to take place it is important to maintain a ph at a minimum value of 9 50.

The treatment of boiler water can be put into two parts. Parameters for cooling tower. Iron oxide is of particular concern in today s boiler water treatment programs. Parameters ph th p al.

Some impurities such as hardness iron and silica are of more concern for example than sodium salts. Hardness chloride 7 3 7 8 2600 1580 800 780 300. Feed water treatment to avoid corrosion make up water to steam boilers should be treated with oxygen scavengers to avoid serious corrosion problems. Maximum flow velocities in water systems water velocities in pipes and tubes should not exceed certain limits.