65 



unsaturated hydrocarbons readily polymerise and take up oxygen 

 or sulphur to form bodies of higher molecular mass — the oxy- or 

 sulphide-bitumens, of which asphalt is the best known. The in- 

 troduction of sulphur into the hydrocarbon molecule may also be 

 effected at an earlier stage, as during the transformation into 

 kerogen. Perhaps the highly sulphurous kerogen of the 

 Kimmeridge shale, from which the heavily charged sulphur oil is 

 derived on distillation, is a sulphide-bitumen. If so, the difficulty 

 so far experienced in reducing the proportion of sulphur is largely 

 accounted for. 



Though the controversy on the origin of bituminous shales 

 and petroleum oils still rages between the supporters of the inor = 

 ganic and the organic theories, it appears to us that the op'nion 

 that they owe their hydrocarbons in the first place to organised life 

 and that of the animal kingdom has most to recommend it. 



The Chemistry of Sulphur in Mineral Oils. 



For over two centuries various attempts have been made to 

 utilise the Kimmeridge shales in one w 7 ay or other, but as we shall 

 see later, all have so far failed, The stimulus of the war has, 

 however, revived interest in them again, so that in the course of 

 the past two years four papers on the subject of Kimmeridge oiJ 

 alone have been read before the Institute of Petroleum Techno- 

 logists. It is felt that the vast potential resources of the Kimmer- 

 idge shale deposits could become a home supply that would con- 

 tribute to a very considerable extent to the large demand for mineral 

 oils in this country, if only the high percentage, some 5 to 8, of 

 sulphur now found in the distillates could in some way be reduced 

 to a reasonable limit. The history of the oil industry, generaMy, 

 supplies several instances where similar problems after careful 

 research have been solved and serious defects removed w.'th com- 

 plete success. Two extensive oil-fields, one in U.S.A., the Lima 

 district in South-Western Ohio, and the other in Canada, between 

 Lakes Huron and Ontario, were for a long time practically as use- 

 less as Kimmeridge shale st : ll is here. The sulphur content of the 

 oils from these fields is much lower than in Kimmeridge oil, aver- 

 aging about 1 per cent. only. The bulk of the sulphur could be 

 taken out by the usual refining methods, but a small residual 

 portion of obstinately held sulphur for a long time defying ah 

 attempts at removal and causing offensive smells rendered 

 the oil of little industrial value. Finally, H. Frash after 

 careful research succeeded in solving the problem of removing the 

 last traces of sulphur from these ''skunk" oils, and to-dav they 

 are just as valuable as the ordinary Pennsylvaman products. Many 

 other oils contain considerable proportions of sulphur, but no 

 special difficulties have been experienced in their refining and they 

 all yield good class distillates. As a matter of fact, strictly speak- 

 ing, all mineral oils contain some sulphur, but mostly in very 

 minute quantities, or such as can be removed by suitable processes. 



