[TABLE 33]
CONVERSION OF A FLUE GAS ANALYSIS BY VOLUME TO ONE BY WEIGHT | Gas | Analysis by Volume
Per Cent | Molecular Weight | Volume times
Molecular Weight | Analysis by Weight
Per Cent |
|---|
| Carbon Dioxide | CO 2 | 12.2 | 12+(2×16) | 536.8 | | | Carbon Monoxide | CO | .4 | 12+16 | 11.2 | | | Oxygen | O | 6.9 | 2×16 | 220.8 | | | Nitrogen | N | 80.5 | 2×14 | 2254.0 | | | Total | 100.0 | | 3022.8 | | |
Application of Formulae and Rules —Pocahontas coal is burned in the furnace, a partial ultimate analysis being:
| |
Per Cent
|
|---|
| Carbon | 82.1 |
| Hydrogen | 4.25 |
| Oxygen | 2.6 |
| Sulphur | 1.6 |
| Ash | 6.0 |
| B. t. u., per pound dry | 14500 |
[Pg 162]
The flue gas analysis shows:
| |
Per Cent
|
|---|
|
CO
2
| 10.7 |
| O | 9.0 |
| CO | 0.0 |
| N (by difference) | 80.3 |
Determine: The flue gas analysis by weight (see [Table 33] ), the amount of air required for perfect combustion, the actual weight of air per pound of fuel, the weight of flue gas per pound of coal, the heat lost in the chimney gases if the temperature of these is 500 degrees Fahrenheit, and the ratio of the air supplied to that theoretically required.
Solution: The theoretical weight of air required for perfect combustion, per pound of fuel, from formula ( [11] ) will be,
| W | = | 34.56 | | = | 10.88 pounds. |
If the amount of carbon which is burned and passes away as flue gas is 80 per cent, which would allow for 2.1 per cent of unburned carbon in terms of the total weight of dry fuel burned, the weight of dry gas per pound of carbon burned will be from formula ( [16] ):