A GREAT NATIONAL ECONOMY.
[TO THE EDITOR Or THE " SPECTAT03:1 was very pleased to read in a recent Spectator (p. 648) : " The State should see to it that we have in existence plant by which, if the necessity arose, we could turn part of our coal supply into liquid fuel" This is, indeed, an urgent national need, and, as the country seems ready to welcome drastic action where great benefits can be shown to result, I submit that steps should be taken at once to forbid the use of bituminous coal for domestic or steam-raking purposes, in order to recover all the valuable by-products which at present are recklessly consumed or go roaring up the chimney in our domestic gasworks— the open grate. It is realized that gasworks coke can never be an acceptable substitute for house-coal, but semi-coke, obtained under a process of low-temperature distillation, makes an excellent fire in an open grate, as I can testify from personal experience, and can be equally well used for steam-raising purposes. The following is an example of the by-products of a ton of bituminous coal, distilled at low temperature r Smokeless fuel, 14 cwt. ; motor-spirit, or toluene (for high explosives), 31 gals. ; middle (or fuel) oil for Diesel oil engines, 54 gals. ; - pitch, 90 lb. ; sulphate of ammonia, 20 lb. ; power-gas, 2,000 c. feet. The above represents the results of tests made with the coal from the seam now being worked at the collieries in East Kent, which, though the coal is friable and unsuited for the domestic grate, gives an average yield of by-products with an unusually firm semi-coke ; it may be taken as a fair average all round. It will be seen that not only fuel-oil, but benzol and toluol, so urgently needed at present, can be obtained in large quantities from the country's own resources and without adding to the immense demand for freightage ; all that is necessary is to create a market for the principal product—the semi-coke. Attention was drawn to the matter in the Houee of Commons just prior to the outbreak of the war, and the First" Lord, in answer to a question, pointed out that " the real problem is how beat to secure the economical industrial use of the various products of coal, particularly of the solid residue of coke." Under the altered circumstances, the problem disappears ; ff the public are forbidden to consume the by-products with the coal, they will be forced to burn the semi-coke ; and I have no doubt at all that the change will be as cheerfully accepted and the benefits as instantly appreciated as in the case of Mr: Willett's Summer Time. In a Presidential Address given at the Institute of Automobile Engineers in 1913 on "The Fuel Question," Mr. J. S. Critchley, M.I.Mech.E., spoke as follows :- "With low-temperature distillation, the temperature for distillation is only about 450° C. as against 1,950' C. in the high-temperature processes employed in gasworks and recovery plants. . . . A process which has recently been developed is known as the Tarless Fuel Process, the principle of which is the carbonization of coal with low temperature and high vacuum. Under this system from four to ten gallons of motor- spirit per ton of coal is claimed, together with a fair yield of fuel suitable for Diesel motors, and a fuel from bituminous coal with a good physical texture and free from tar."
And, a little later :-
"Many projects have recently been put forward for the more general utilization of coke, and therefore the increased production of tar and fuel-oils and benzoL It is estimated, for example, that if coke were burned in houses instead of coal, there would be an ample supply of fuel for the automobile trade, besides heavy oil for Diesel engines and steam boilers. These schemes, however, are mere visions. There is little doubt that our system of using coal is not by any means an economical one."
The yields of the various by-products as set forth in the fourth sentence of my letter were the result of distillation by the process to which Mr. Critchley draws attention. It should be noted, however, that there are several low-temperature systems of coal carbonization claiming equal or even better results, and no doubt the ideal retort has still.to be found. The whole subject offers a fruitful field for research and experiment. Meanwhile, any one of the systems available to-day can speedily be put into operation on a large scale so long as the principal product, the smokeless fuel, finds a ready market.—I am, Sir, &c.,
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