Boiler Feed Water Properties
Requirements for boiler feed water design and requirements include maximum tolerance levels of alkali, salt, silica, phosphates and other elements. This is in proportion to the pressure at which the boiler will be operated. These boiler water levels must be gotten from the boiler manufacturer, and are basically based on the boiler water properties.
water treatment scheme for boiler feed water
Below tables are the recommended boiler feed water properties / boiler feed water chemical characteristics (levels) Â taken from APAVE. Which is the Association of electrical and steam unit owners), up to pressures of 100 bar for medium steaming rates and for volumes of water in the chambers sufficient to properly control the blow down rates, and from ABMA (American Boiler Manufacturers Association) in its standard guarantee of steam purity.
| Boiler Working Pressure (Bar) | |||||||||
| 0 – 20.7 | 20.8 – 31.0 | 31.1 – 41.4 | 41.5 – 51.7 | 51.8 – 62.1 | 62.2 – 68.9 | 69.0 – 103.4 | 103.5 – 137.9 | ||
| Boiler Feed water | |||||||||
| Dissolved oxygen (measured before oxygen scavenger addition) | 0.04 | 0.04 | 0.0070 | 0.007 | 0.0070 | 0.007 | 0.007 | 0.007 | |
| Total Iron | mg/l | 0.1 | 0.05 | 0.03 | 0.025 | 0.02 | 0.02 | 0.01 | 0.01 |
| Total copper | 0.05 | 0.025 | 0.02 | 0.02 | 0.015 | 0.015 | 0.01 | 0.01 | |
| Total hardness(CaCO3) | 0.3 | 0.3 | 0.20 | 0.2 | 0.1 | 0.05 | not detectable | ||
| Non volatile TOC | 1 | 1.0 | 0.5 | 0.5 | 0.5 | 0.20 | 0.2 | 0.2 | |
| Oily matter | 1.0 | 1 | 0.50 | 0.5 | 0.50 | 0.2 | 0.2 | 0.2 | |
| pHÂ at 25 | 7.5 – 10 | 7.5 – 10 | 7.50 – 10.0 | 7.50 – 10.0 | 7.50 – 10 | 8.5 – 9.5 | 9.0 – 9.6 | 9.0 – 9.6 | |
| Boiler Water | |||||||||
| Silica | mg/l | 150 | 90 | 40 | 30 | 20 | 8 | 2 | 1 |
| Total alkalinity (CaCO3) | 350 | 300 | 250 | 200 | 150 | 100 | not specified | ||
| Free hydroxide alkalinity CaCO3 | not specified | not detectable | |||||||
| Specific conductance at 25 without neutralization | mS/cm | 3500 | 3000 | 2500 | 2000 | 1500 | 1000 | 150 | 100 |
| Boiler Working Pressure (Bar) | ||||||||
| 0 – 15 | 15 – 25 | 25 – 35 | 35 – 45 | 40 – 60 | 60 – 75 | 75 – 100 | ||
| Boiler Feed water | ||||||||
| Dissolved oxygen (measured before oxygen scavenger addition) | mg/l | 0.02 (Physical removal of dissolved oxygen) | ||||||
| Total hardness | French degrees | 0.5 | 0.3 | 0.2 | 0.1 | 0.05 | 0.05 | 0.05 |
| Oily matter | mg/l | absence | 0.05 | 0.05 | 0.05 | |||
| pH | > 8.5 | |||||||
| Total Iron | mg/l | not specified | 0.05 | 0.05 | 0.03 | |||
| Total copper | not specified | 0.03 | 0.03 | 0.01 | ||||
| Boiler water | ||||||||
| MÂ alkalinity | French degrees | 100 | 80 | 60 | 40 | 15 | 10 | 5 |
| P alkalinity | 0.07 M | 0.070 M | 0.07 M | 0.070 M | > 0.5 M | > 0.5 M | > 0.5 M | |
| SiO2 | mg/l | 200 | 150 | 90 | 40 | 15 | 10 | 5 |
| TDS | 4000 | 3000 | 2000 | 1500 | 500 | 300 | 100 | |
| Phosphates | 30 to 100 | 31 to 100 | 20 to 80 | 21 to 80 | 10 to 60 | 10 to 40 | 5 to 20 | |
| pH | 10.5 to 12 | 10 to 11 | ||||||
| Make up water | Softened or softened and carbonate free | Demineralized | ||||||
- Published in Water Treatment
