THE COLLIERY GUARDIAN AND JOURNAL OF THE COAL AND IRON TRADES. Vol. CXV. FRIDAY, FEBRUARY 22, 1918. No. 2982. A New British Oil Industry.* By E. H. CUNNINGHAM CRAIG, B.A., F.R.S.E., F.G.S. Of the several sources from which oil can be obtained in this country by distillation, viz., oil shales, coal, cannel coals and torbanites, blackband ironstones, lignite, and peat, the only source at present being utilised is oil shale, the working and treatment of which are confined to Scotland. Of the others, coal yields too little, and is too valuable, to be utilised on a large scale; lignites are not yet sufficiently opened for development; and peat has proved troublesome and expensive to treat owing to the difficulty of elimi- nating water. This leaves cannel coals, torbanites, and blackband ironstones, which are closely associated, and in many cases easily to be obtained. Cannel. Cannel coal differs from ordinary coal by being less highly carbonised: it contains many fragments, strings, and particles of vegetable matter still showing their natural forms, though flattened by pressure, and sometimes the internal vegetable structure is also still in evidence. The percentage of hydrogen to carbon is higher than in ordinary bituminous coal, the per- centage of inorganic matter is usually higher also, and the fracture and general appearance serve to distin- guish this variety of carbonaceous deposit. The lustre is sometimes dull, sometimes bright, the fracture is conchoidal or semi-conchoidal, and lamination is as a rule not well-defined. Most cannels contain a very large number of both macro- and micro-spores: usually “ jetonised ” and appearing dark yellow or reddish- brown in thin microscopic sections. They are believed to yield on distillation waxes and resinous compounds, whilst the other vegetable bodies yield tarry oils and tarry acids. Torbanites. Torbanites, though very similar in outward appear- ance, are essentially different from true cannels, and are known in many of our coal fields, e.g., North Staf- fordshire, Northumberland, Fife, Lanarkshire, and Cumberland, though none sp far discovered is so rich as the typical “ Torbanehill mineral.” A torbanite consists essentially of a coal matrix, in which are embedded certain oval, spherical, or irre- gular yellow or brown bodies, which have been desig- nated conveniently as kerogen. These bodies have been described as algse, macro-spores, or resin globules by different authorities. Extensive researches have proved that these kerogen globules contain a consider- able proportion of inorganic mineral matter in close, and apparently chemical, combination with hydro- carbons of organic origin. Torbanite, in fact, forms a half-way stage between the carbonaceous and the petroliferous phases ; and where torbanites are frequent in the upper members of a thick coal measure series, seepages of crude petroleum are equally prominent in the lower strata. Torbanites have a clean conchoidal fracture as a rule, a fairly high percentage of ash, and a streak that varies from yellow to dark brown. ‘ The kerogen globules vary greatly in size, shape, and numbers in different deposits of this nature, and undergo a form of degeneration in four stages. This degeneration is in effect a species in inspissation, and the quality of the oil yielded by distillation varies according to the stage attained. Cannels and torbanites, however, are inextricably mixed up. There are few cannels that do not contain some kerogen globules ; whilst torbanites contain uncar- bonised vegetable matter, spores, cuticle, etc., just as cannels do; and every gradation between a typical tor- banite and a typical cannel is found. Most English torbanites are known as cannels or gas coals, or some- times even as black shales when the lamination is dis- tinct ; and it is therefore convenient to class both tor- banites and cannels under the generic title of cannel when dealing with practical questions of oil produc- tion. But one important point must be noted: the kerogen globules yield on distillation oils of the paraffin series and olefines, and the fresher and less degenerated the kerogen the greater the quantity of light oils pro- duced. The most degenerated types yield quantities of heavy paraffin waxes. Thus it is possible by micro- scopic examination of a deposit of this nature to make a good rough estimate, not only of the quantity of oil per ton that can be obtained, but also of the quality of the oil. Besides true cannels, there are also bastard cannels and impure coaly or canneloid bands that cannot be sold as coal, and accumulate on the waste heaps. Such bands have various local names in different parts of the country, e.g., Jacks, Rattle jacks, Gees, Rattlers, Batts, etc. These deposits, which in many cases have * From a paper presented to the Institution of Petroleum Technologists on February 19. to be worked with the seams, contain kerogen globules and uncarbonised vegetable matter from which oil can be obtained by distillation, and therefore such material has a distinct value, entitling it to be regarded as something more than a waste product of the mine. Blackband Ironstones. Many of the famous seams of blackband ironstone have been worked out, but there still remain a great number of inferior or thin seams which can be utilised. They are essentially ironstone seams, in which there is a very intimate association of iron oxide or hydrate with carbonaceous material. Microscopic examina- tion has proved that the carbonaceous contents are kerogenous, or only slightly carbonised, and are capable of yielding oil by distillation. In many such seams the ironstone is associated with cannel seams highly torbanitic in character. Such seams, if worked at all, are heaped in bings in the open and set fire to, a certain .quantity of coal usually being mixed with the material to start combustion, carbonaceous material in the ironstone being sufficient to support combustion, and effect the complete calcination of the iron. A better use for the blackband seams has been devised by Mr. D. V. Hollingworth, whose process enables the oil contents of a blackband seam to be extracted by distilling the volatile matter, the fixed carbon being left in association with the iron. It is claimed that the ironstone thus treated is in a better condition for treatment in a blast furnace, that some 4 cwt. of coke per ton of ironstone can be saved, and that the extraction of the metal as pig iron can be effected more quickly and possibly at a slightly lower temperature, thus ensuring less wear and tear in the furnace. Furthermore, in the preliminary retorting, the nitrogen contents of the deposit can be collected as ammonium sulphate, and it is possible to retort at such a temperature that sufficient uncondensable gas is produced to supply the heating power to the retorts, and thus make the process practically self-supporting. This method does away with a very wasteful process, reduces fuel consumption both in bings and blast fur- naces, furnishes the latter with a superior raw material, and makes available two valuable by-pro- ducts—oil and ammonium sulphate. New Industry. On the basis of these various deposits, cannels and bastard cannels, torbanites and blackband ironstones, it is proposed to found a new industry in this country. This industry will be simply the low-temperature car- bonisation of the material, with the extraction of oil and all by-products that can be produced in sufficient quantity. Several low-temperature carbonisation processes have been demonstrated experimentally and on a fairly large scale, and all have their respective merits, advan- tages, and disadvantages. Material that intumesces and cokes is unsuitable for some forms of retort, but can be dealt with in others; so that the particular material to be treated in each district must be con- sidered. The great objection to any low-temperature process is that the maximum production of ammonium sulphate cannot be obtained unless retorting is carried out at a fairly high temperature. On the other hand, working at a high temperature loses the bulk of the light oils, which are cracked, with the formation of large quantities of uncondensable gas. But here the scientific classification of the various deposits to be dealt with comes to our aid. A torbanite yields at the best a small percentage of ammonium sulphate, but a large percentage of light oils, especially if the kerogen has not suffered greatly from degeneration. On the other hand, a true cannel may yield but little light oil, but a large percentage of ammonium sulphate. For the %former, therefore, a low-temperature carboni- sation is indicated, and for the latter as high a temper- ature as is consistent with an adequate production of oil. In most cases, doubtless, a compromise can be arranged on the basis of the most economical work- ing ; sufficient gas to heat the retorts must be pro- duced, and at the temperature necessary to produce that quantity of gas, though the maximum yield neither of light oil nor of ammonium sulphate could be obtained, the production of both might well be sufficient for practical working. Alternatively, it should be possible in many cases to utilise the residue after retorting in a producer to make all the gas neces- sary for running the plant, and at the same time recover all the ammonium sulphate. The most econo- mical method in each case will be determined by local conditions, and by the particular characters of the raw material, thus necessitating an efficient control of method by research experts. Probable Yield. Few cannels—and these are all torbanitic—can be counted upon yielding as much as 50 gals, of water-free oil per ton, though many are capable of 40 gals. The worst of the bastard cannels can be expected to yield from 20 to 25 gals., and unless oil of unusually good quality be produced, or the amount of available material be very large and easily and cheaply obtained, it would probably be inadvisable to treat material giving a lower yield than 25 gals, per ton. Blackband ironstones may give a much lower yield, but they are in a different category, the iron being the primary product. Over the whole country it is probable that the cannels and torbanitic cannels can be counted upon to give an average yield of from 33 to 35 gals, of crude oil per ton. This oil will naturally vary in quality according to the nature of the raw material and the method of retorting employed. The petrol percentage will probably vary between 4 and 10, and refining for the purpose of producing fuel oil should yield from 60 to 70 per cent, of the crude oil. The maximum of ammonium sulphate that can be obtained’, calculated upon the nitrogen content of the raw material, is large in many cases, running to over 60 lb. per ton, but except where high-temperature car- bonisation is employed, or the residues from a low- temperature process utilised in a producer, the maxi- mum cannot be recovered. Low-temperature retorting alone cannot be expected to yield more than 20 to 25 lb. per ton. It is therefore difficult to make any estimate of what an average yield of ammonium sulphate for the country would be, but let it be taken for purposes of comparison at from 30 to 40 lb. per ton of material retorted. The yield of solid paraffin wax is not likely to be so large as in the case of the Scottish oil shales. The Scottish oil shale companies obtain a yield of oil approximately 22 gals, and 42 lb. of ammonium sulphate per ton. Thus, so far as oil is concerned, cannel distillation has a decided advantage, but the position as regards ammonium sulphate is reversed. As regards the cost of raw materials, the oil shale mined and delivered at the retorts in Scotland costs approximately 5s. 6d. per ton, and therefore very inferior shale, so far as oil yield is concerned, can be worked, if the production of ammonium sulphate is high. The cannels and torbanites cannot be expected to be obtained at such a low average price. There is a large quantity of what is really waste at collieries that could be obtained more cheaply, but when cannel seams have to be specially worked, or larger timbering becomes necessary to allow of the floor or roof of a seam to be extracted and brought to bank, the mining costs must be considered. Again, the miners, if required to load the hutches with cannels and bastard cannels as well as coal, may demand to be paid for it as coal. But with contracts made for the retortable material which can be mined without difficulty, yet which it is in the collieries’ interests not to permit to be mixed with the coal, a fair price can no doubt be arrived at. There are few collieries which, before the war, would not have been glad to ensure a price of 7s. per ton for such retortable material as they have to mine with the coal. Cannel seams specially opened and worked, and some of the rich cannels that have always had a good sale to gas works, must be considered differently. It is obvious that the success of a cannel distillation industry must depend upon the cordial co-operation of coal owners, and that therefore a fair price must be paid for the raw material. Taking the good with the bad, it is probable that the average price to be paid over a term of years would not be greater than 10s. per ton. Oil shale leaves an enormous quantity of useless residue after retorting; and this has to be loaded and transported to huge tips which are constantly increas- ing in size, while rental of new land for new tips is a recurring expense. But the residue from the retort- ing of cannel can be worked up into very fair briquettes, whilst the residues from the better grades can be utilised in producers, to give not only all the power gas that is required, but the full yield of sulphate of ammonia. Thus the residues may be made a source of profit, and there can be little doubt that it is on the use of the residues that the success or failure of a cannel distillation industry depends. The industry must be started on broad lines and on a large scale; and in this connection the experience of the Scottish shale companies is useful. Of the 50-odd companies that once existed, only five have survived, and it was only those that had sufficient financial resources to buy up the businesses and fields of those that failed, bring them under one management, work on a large scale, and practise every economy in hand- ling, retorting, and refining, that finally attained to a secure financial position. So in cannel distillation, only large central works must be projected, and they must be placed with due regard to supplies of retortable material and facilities for transport. The through-put of cannel should be at least 1,000 to 2,000 tons per day, and in some instances it might be more.