Table 13-3. Example of savings with installation of automatic blowdown equipment (basis: one day).
| Evaporation | 2,400,000 | lb/day |
| Boiler Pressure: | 600 | psig |
| Manual blowdown: | 183,423 | lb/day (7.1%) |
| Automatic blowdown: | 145,069 | lb/day (5.7%) |
| Blowdown Reduction: | 38,354 | lb/day |
| Feedwater temperature: | 240 | °F |
| Makeup water temperature: | 60 | °F |
| Heat of liquid at 600 psig | 475 | Btu/lb |
| Heat of liquid at 60°F | -28 | Btu/lb |
| Heat required: | 447 | Btu/lb |
| (blowdown reduction) | X 38,354 | lb/day |
| Heat reduction: | 17,144,238 | Btu/day |
| Fuel (gas): | 1,040 | Btu/ft3 |
|
(@ 80% boiler efficiency) |
X .80 |
|
| Available fuel heat: | 832 | Btu/ft3 |
| (heat reduction) | 17,144,238 | Btu/day |
|
|
÷ 832 | Btu/ft3 |
| Fuel reduction: | 20,606 | ft3/day |
| Fuel savings @ $4.00/1000 ft3: | $ 82.42 | |
| Labor reduction: | 0.5 | hr |
| Daily labor savings @ $30.00/hr | $ 15.00 | |
| Water reduction: | 4,598 | gal/day |
| Daily water savings @ $ 0.80/1,000 gal: | $ 3.68 | |
| Total daily savings: | $101.10 | |
| X 365 | days/yr | |
| Annual savings | $36,902 |