280 REPORTS ON THE STATE OF SCIENCE, ETC. 



The Committee then proceeded to inquire into the origins of our present 

 imported oil-fuel supplies, and for that purpose the statistics for the year ending 

 1921 were analysed (see Table II.) so as to discriminate between the various 

 countries of origin, and also to show how much of our total imported supplies 

 of petroleum and petroleum products are being drawn from within the Empire 

 itself. 



The Committee considers it important that attention should be drawn to the 

 fact that, inasmuch as the home production of shale oil is now very small, i owing 

 to the relatively low cost of production of imported petroleum, we are at present 

 dependent almost entirely on countries outside the Empire for the supplies of 

 natural petroleum and petroleum products, a most undesirable and dangerous 

 state of affairs from every point of view. 



The Gas and Coking Industries as Producers of Motor Spirit. — It would 

 appear that the only practicable way in which future home supplies of motor 

 spirit and fuel oils can be extended is by the carbonisation of bituminous coals 

 at temperatures between 600° C. and 1200° C. By carbonising suitable British 

 coals at high temperatures (1000° C. to 1200° C.) in gas retorts or by-product 

 coke ovens there can be obtained between 3 and 6 per cent, of the weight 

 of the dry coal as anhydrous tar, and between 0.75 and 1 per cent, of its 

 weight as refined benzole (motor spirit). It should be borne in mind, how- 

 ever, that, inasmuch as more than half of the coal so carbonised is for the 

 production of hard metallurgical coke, the total production of motor spirit 

 and tars by these methods depends very largely upon conditions in the iron 

 and steel industries which fluctuate and at the present time are exceedingly 

 bad. Supposing, however, that pre-war prosperity were restored to the iron 

 and steel industries, a total high temperature carbonisation of some 40 million 

 tons of coal per annum might reasonably be expected. Taking 1 per cent, of 

 its weight as a probable outside limit for the ultimate production of refined 

 benzole, the total potential production of the latter would not exceed 400,000 tons 

 per annum, which is very little more than half the tonnage of the motor 

 spirit actually imported into the country in the year 1921. Aloreover, of this 

 potential supply nearly half would have to be drawn from the gasworks of 

 the country, and it is at least problematical whether it would pay the gas 

 companies to extract the benzole from their gas at present prices. Indeed, 

 taking the present relative prices of gas and benzole, as well as the costs of 

 recovering benzole from coal gas, it is probable that the cash value of the 

 potential heating power of benzole is greater when left in the gas than it is 

 when extracted therefrom and (after subsequent refining) sold as motor spirit. 



Low Temperature Carbonisation of Coal as a Future Source of Oil Fuels. — 

 Therefore, it has to be recognised that the most promising internal supply 

 of both motor spirit and fuel oils lies in the direction of the low-temperature 

 carbonisation of coal, provided that methods can be devised for same which 

 are sound both from the technical and the commercial points of view. A 

 really successful solution of this problem is greatly to be desired, not only 

 for the aforesaid reasons, but also because it would be a great factor in the 

 abolition of the smoke nuisance, especially from domestic fireplaces. The 

 Committee has paid close attention to the recent developments with regard to 

 this matter which are taking place in this country. In this connection 

 attention may be drawn to : — 



1. The description of the operation of the experimental plant at Barugh, 



near Barnsley, as published in Engineering of October 28, 1921. 



2. The Conference on low-temperature carbonisation which was held at 



Cardiff on April 20, 1922, under the auspices of the South Wales 

 Institute of Engineers. 



3. The paper read on April 3 last on ' The Influence of Structure on the 



Combustibility and other Properties of Solid Fuels,' by Messrs. 



E. R. Sutcliffe and E. C. Evans, before the London Section of the 



1 Thus in the year 1920 the amount of oil-shale mined in Great Britain 

 was 2,840,859 tons, from which it may be estimated that no more than about 

 227,000 tons of oil would be produced. 



