HIGH TEMPERATURE CARBONIZATION OF COAL 407
a small portion of coal was distilled in a boat and the volatile products were subjected to various conditions. In the first case they were remo ved from the heated tube with the utmost rapidity ; secondly, they were subjected to the radiant heat of the tube ; and, thirdly, they were collected after passage through a heated coke surface. The results obtained go clearly to show that the last-named condition. is attended. by the most severe forms of degradation. A summary of these results is given here, and Table I indicates the percentage composition of the gas obtained under the different conditions.
TABLE I
Percentage Composition of Nitbogen-Fbeb Gas
Minimum heat action. Radiant heat. Hot coke surface.
Per cent. Per cent. Per cent.
Unsaturated hydrocarbons .... 6-3 5-0 3-3
Methane 33-1 30-9 27-3
Hydrogen 42-5 46-6 51-2
Carbon monoxide 13-1 14-3 14-7
Carbon dioxide 4-3 3-4 3-2
Oxygen 0-7 0-1 0-5
At the same time the actual volume of each constituent obtained in cubic centi-metres per gramme of coal was recorded. In Table II these figures have been reducecL to cubic feet per ton.—a measurement with which the gas engineer is more familiar.
TABLE II
Yieijj of Nitrogen-Fbee Gas
Minimum heat. Radiant heat. Hot coke surface.
Expt. I. Expt. II. Expt. I. Expt. II.
Unsaturated hydrocarbons 538 525 563 287 472
Methane 3,157 3,552 3,444 3,516 3,588
Hydrogen 4,197 5,346. 5,238 6,315 6,708
Carbon monoxide .... 1,614 1,614 1,471 2,045 1,937
Cubic feet per ton 9,506 11,037 10,716 12,163 12,705
It is seen that the result of subjecting the volatile products to the action of radiant heat is an. increase of about 14 per cent, in “ make ” per ton, whilst by passage through, the column of heated coke the increase amounts to 30 per cent. That the quality of the gas is lowered by the decomposition which. has resulted from the further action of heat is shown by the reduction which. has occurred in the propor-