With 18 parts of steam and 12 parts of carbon we can obtain by the former equation 28 parts of carbon monoxide and 2 parts of hydrogen. This forms an extremely calorific mixture.
There are several processes for preparing water gas which give good practical results, and the gas produced has been used in America and Germany for lighting towns on the incandescent gas-burner system.
The Strong and Lowe processes consist of a furnace lined with fire-bricks, and in which is placed coal or coke. When this mass of carbon has reached a state of bright incandescence by playing upon it a stream of air, steam is admitted at high temperature, and is decomposed by the carbon forming oxides and liberating hydrogen. The gaseous products pass from the furnace to a reservoir.
When the chemical action ceases, due to cooling of the carbon, the steam is shut off and the stream of air turned on till it becomes incandescent once more. The process of admitting steam is then repeated.
About 2½ lbs. of coke are necessary to produce 20 cubic feet of water gas.
Analysis of the gas reveals the following parts by volume of the constituents.
(1) Water gas produced by the Strong process:—
| Hydrogen | 53 | volumes |
| Carbon monoxide | 35 | ” |
| Hydrocarbons | 4 | ” |
| Other gases | 8 | ” |
| —— | ||
| 100 | volumes |
(2) Lowe process:—
| Hydrogen | 30 | volumes |
| Carbon monoxide | 28 | ” |
| Hydrocarbons | 34 | ” |
| Other gases | 8 | ” |
| —— | ||
| 100 | volumes |