Some impurities such as hardness iron and silica are of more concern for example than sodium salts.
Boiler feed water hardness limit.
Maximum flow velocities in water systems water velocities in pipes and tubes should not exceed certain limits.
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.
A total hardness as c a co 2 mg l max.
Iron oxide is of particular concern in today s boiler water treatment programs.
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.
Steam boiler rating and feed water temperature boiler output and feed water.
Parameters for cooling tower.
The treatment of boiler water can be put into two parts.
Internal treatment protects against feed water hardness by preventing.
Parameters for boiler water.
These are internal treatment and external treatment.
Hardness chloride 7 3 7 8 2600 1580 800 780 300.
Parameters ph th p al.
Phosphates are used to react with calcium hardness in the boiler water.
Parameter control ph tds total hardnes ca.
Feed water treatment to avoid corrosion make up water to steam boilers should be treated with oxygen scavengers to avoid serious corrosion problems.
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.
This value will limit the silica content of the steam to 0 25 ppm as a function of selective.
Feed water purity is a matter both of quantity of impurities and nature of impurities.
In order for this reaction to take place it is important to maintain a ph at a minimum value of 9 50.
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.
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.
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.
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.
