In many cases, authors on the subject have given purely theoretical results, without allowing for losses in the furnace.
The fuels to be considered are anthracite and bituminous coals, crude petroleum, and coal, generator and water gases.
The average compositions of these fuels (considering only the heating agents), as deduced from the analysis of eminent chemists, are:
PERCENTAGE BY WEIGHT.
| C | H | O | CO | CH4 | C2H4 | |
|---|---|---|---|---|---|---|
| Anthracite | 87.7 | 3.3 | 3.2 | |||
| Bituminous | 80.8 | 5.0 | 8.2 | |||
| Petroleum | 84.8 | 13.1 | 1.5 | |||
| Coal gas | 6.5 | 14.3 | 52.4 | 14.8 | ||
| Generator gas | 1.98 | 35.5 | 1.46 | |||
| Water gas | 6.3 | 0.6 | 87.8 | 1.2 |
We will employ the formula of Dulong—
h = 14,500 C + 62,000 (H - O/8)
to compute the theoretical heating powers of these fuels. In the case of methane, CH4, the formula is not true, but the error is not great enough to seriously affect the result. This gives for the combustion of one pound of:
Anthracite 14,500 Br. Heat Units.
Bituminous 14,200 " " "
Petroleum 20,300 " " "
Coal gas 20,200 " " "
Generator gas 3,100 " " "
Water gas 8,500 " " "
Reducing the above to terms of pounds of water evaporated from 212° F., we have: