Treatment and Control of Feed and Boiler Water
Natural water is not usually suitable for boiler feeding unless it is suitably treated. The use of an untreated water can cause foaming and priming, corrosion of the metal and restriction of the water spaces due to scale deposition. Serious scaling may result in ultimate failures of generating tubes and leakage at tube expansions. It also reduces the heat transfer and consequently the efficiency of the unit.
The boiler water analysis must be maintained within the following limit to ensure maximum boiler protection and steam purity. We recommend the boiler user adopt the service and guidance of a specialist company supplying water treatment chemicals.
Recommended Boiler Drum Water Concentration
| Total dissolved solids | less than | 3000 ppm |
| Suspended solids | less than | 100 ppm |
| Hardness | zero | |
| pH | 10.5-11.5 | |
| Oil, grease. Etc. | zero | |
| Silica (as SiO2) | 25 ppm normal | 100 ppm max |
| Phosphate (as PO4) | 30-50 ppm | |
| Sulphate (as Na2SO3) | 30-50 ppm | |
| Sulphate to caustic ratio | 2.5 |
Recommended Feedwater
| Dissolved oxygen | less than | 0.03 ppm |
| pH | 8.5-9.5 | |
| Hardness | zero | |
| Suspended matter | zero | |
| Oil, grease | zero |
Blowing Down
The total dissolved solids level in the boiler water is maintained at an acceptable level by means of a timer controller blowdown system.