The Oil Shales of Norfolk, 1920

From the Oil Shale Industry in Scotland and England

By Victor C. Alderston

Excerpts from the Quarterly of the Colorado School of Mines, October 1920

The Kimmeridge clay formation in Norfolk County has been well explored by open cuts, bore holes, and shafts, in the region south of King's Lynn and east of Ouse. The oil shale appears in two series; the upper called the Smith's series and the lower the Puny Drain series, virtually at the top of the Kimmeridge clay. An open cut or quarry on the property of the English Oilfields, Ltd., shows a seven foot stratum of oil shale, wet and oily, beneath an overburden of from 13 to 30 feet In thickness. The dip Is 5 degrees to the east. The deposit has been tested by pits and bore holes over· an area of two square miles. A 50 foot shaft, 6 by 12 feet, has been sunk to an eight foot stratum of oil shale. This stratum consists of two distinct layers: the upper, or black shale, 3 feet 6 Inches thick; and a lower stratum, 4 feet 6 inches thick. The roof is soft so that the walls and roof of the main drifts need to be bricked. A sample of the shale tested at the Colorado School of Mines gave: Oil, 17 gallons per ton; sulphur, 5.48 per cent

English Oilfields Ltd

The English Oilfields, Ltd., is the largest oil shale company in the Norfolk district. It owns, or controls by long lease, sixty square miles of territory. It is capitalized at £1,500,000 ($7,500,000) in shares of one pound sterling each. The company is making extensive improvements on their property consisting of a branch from the main line of the Great Eastern Railway; houses for workmen; retorts, condensers, scrubbers, refinery shops, and by product plant, with the intention of establishing a plant complete in all details. Besides it has erected and tested several retorts for the distillation of its shale.

The Removal of Sulphur from Oil Shale

Fortunately for the oil shale Industry in the United States, sulphur in the oil shale here has not yet been found in quantity to be detrimental to the oil produced. Also, there is little or no sulphur in the Scottish shale. But in England the known beds of oil shale all carry so much sulphur as to make the oil unmarketable except for fuel. During the war, the British Admiralty raised the allowable limit of sulphur In oil to three per cent., but paid a low price for any above two per cent. The one great obstacle standing in the way of the development of the oil shale industry in England is the desulphurlzatlon of the shale without spoiling the oil. Logically there are three methods of attack.

• A. During the retorting of the shale an attempt may be made to remove the sulphur by such agents as lime and caustic soda.
• B. As soon as the oil vapors and gas are evolved, and before condensation, they may be passed over desulphurizing agents. ·
• C. After the vapors have been condensed the oil may be desulphurized by some chemical means.

Many patents have been taken out to cover processes and many individuals claim to have a solution, yet no process has yet appeared that satisfies commercial and industrial requirements. During the Great War the need of a domestic supply of oil was felt so keenly by the British Government that it investigated every possible source of supply. In the case of oil shale the presence of an excess of sulphur stood as an insurmountable obstacle. It remains the great unsolved problem before the technical men of Great Britain. When Its solution comes, as it probably will some day, great quantities of oil shale in the Kimmeridge formation, now commercially valueless, will become a source of great wealth to the British Empire, and of economic importance in supplying an additional domestic supply of oil.

Besides the technical point of view, it is to be observed that, in an utilitarian age like the present, the aesthetic objection to the odor of sulphur bearing oil may have to be ignored because of grim industrial necessity. Also sulphur bearing oils may have to be mixed with non-sulphur bearing oils to reduce the average percentage of sulphur below the objectionable point. However, the only solution that will be permanently satisfactory will be the production of sulphur free from oil.

Sulphur occurs in shale oil and petroleum both in the form of organic and inorganic compounds, and even as free sulphur dissolved in the oil. The sulphur in inorganic compounds may usually be removed without much difficulty, either in the process of distillation, or by treatment of the distillate. Some organic compounds of sulphur are more or less decomposed by distillation, so that a partial removal of the sulphur is easily elected, but the complete elimination of organic sulphur from an oil may prove very difficult commercially. The exact conditions or combinations in which the sulphur exists, which are not definitely known, and which may vary in different oils, add to the difficulties of the case. Many methods have been proposed for the elimination of sulphur and some have proved successful with certain oils. Unsaturated organic compounds containing sulphur can be removed with sulphuric acid, but ordinary sulphur free, unsaturated compounds are more easily attacked, and, therefore, it the oil contains a large percentage of the latter, the process becomes too expensive. Also, it is possible for sulphur to be actually added in the process by the formation of sulphonic acids. Liquid sulphurous acid has been used in the Edeleanu process to remove sulphur. It combines with the unsaturated sulphur compounds and settles out of the oil. But not all the sulphur is necessarily in combination with unsaturated compounds. Metallic oxides, such as cupric oxide, have been employed to combine with and eliminate sulphur. This is done, either by bringing the hot vapors of distillation in contact with the oxide, or agitation of the latter with the hot oil. By the Frash process the amount of sulphur can be reduced to 5 per cent without spoiling the oil, but not below that point. These and other methods are employed with more or less success according to the nature of the oil, but the problem as a whole is apparently still unsolved.

Investigations by the British Government

On account of the shortage of petroleum and its products during the Great War, especially fuel oil for the Admiralty, the British Government directed its attention to the possible production of petroleum from home supplies; i.e., from Scotland and England alone. First of all, efforts were made to increase production from the known deposits of oil shale in Scotland by speeding up the mining of raw shale, by using to full capacity of the retorts in use, and by putting in use older retorts that had been lying idle. By these efforts the output was increased, but not to a degree sufficient to meet the pressing needs. Investigations were then carried on with the deposits of oil shale which were known to exist in Dorsetshlre, Norfolk and elsewhere, but on investigation these shales were found to produce an oil too high in sulphur for Admiralty purposes and various retorts and processes were tried in order to produce a suitable oil from these shales and an oil which was free from sulphur. In 1917 the Inter-departmental Committee carried out experiments with the Del Monte retort. a low temperature distillation process, on the Kimmeridge shales which gave an output of 45 gallons a ton, but carried 6.6 per cent. of sulphur. An endeavor was then made to find a process for eliminating this sulphur, and from June to October, 1917, experiments were carried on and investigations made of the process invented by Heyl which failed to produce the results obtained by the inventor. Other processes examined were Burnet's process for desulphurizing the oil obtained from the Norfolk shales. Still other processes investigated were Tozer's system for producing oil by low temperature vacuum process distillation, the S.O.S. system for the retorting of sewage sludge, the Simpson system, the Moeller system, the Maclaurln system, and the Lamplough process. Oil shales from other parts of the country were also investigated, namely, at Anglesey, and at Skipton in Yorkshire. Having failed to find any satisfactory process for eliminating this sulphur, attention was directed to the cannel coal and torbanite which were known to exist in various parts of the country, and which were capable of producing a high percentage of oil.

General Observations

The English oilshale deposits are essentially different from those investigated elsewhere and present specialized problems of desulphurlzatlon, retorting, and refining. They are particularly characterized by;

• a. A high specific gravity.
• b. A large content of olefines and unsaturated hydrocarbons.
• c. A low content of the paraffin and naphthenic series.
• d. A high percentage of sulphur.

To those who foresee a high price for the ammonium sulphate produced from shale a note of warning should be sounded. The high price of ammonium sulphate, obtainable in Scotland, is the result of peculiar local and industrial conditions and should not be regarded as a criterion for the United States. Here the synthetic production of ammonium sulphate has progressed to such a point that its market price in the future will be lower than it has been in the past, so that a high price for ammonium sulphate, as a product from crude shale oil, should not be counted upon.

Good oil shales have low specific gravities. The specific gravity of ordinary clay shale varies from 2.4 to 2.5. The specific gravity of oil shale is seldom more than 2.4 and may go as low as 1.4. As a general rule the lower the specific gravity the richer the oil content.

Directory of Scottish and English Oil Shale Retorts

Scotch Practice:

Wm. Fraser, Manager-Director Scottish Oils, Ltd., 135 Buchanan Street, Glasgow, Scotland.

Vertical, circular type ; two sections; upper section of cast iron; upper diameter, two feet ; lower diameter, 2 feet 4 inches ; height, 11 feet; lower section enlarged to three feet in diameter; 20 feet high; entire retort encased in brick; four retorts in a house; 16 houses form a bench; throughput 3 to 4 tons in 24 hours ; temperature in the upper section, 990 to 1000° Fahr., In the lower section 1800 to 2000° Fahr.; shale broken only to about the size of one's two fists; feed and discharge continues; externally gas heated; gas from the shale generally sufficient but an auxiliary gas producer Is kept in readiness for use when lean shale is retorted and supply of gas from the shale is insufficient; exhaust steam is injected at the bottom; gas and oil vapors are drawn out at the top ; less steam is needed If shale Is In large pieces, more If shale is small; rich shale takes more time for retorting; lean shale less time; gas and oil vapors are produced In the upper chamber. ammonia In the lower chamber.

This type of retort is used In all the Scottish plants and has been in successful commercial operation for twenty years. It is designed especially for the maximum production of ammonium sulphate. Minor changes have been made, but these changes are only in the mechanical details of the feed and discharge; and In the shape of the cross section; e.g., In the Pumpherston retort the spent shale drops out at the bottom, but ln the new Thompson retort the shale comes out through a door at the side. The Broxburn retort has an oval and the Thompson an oblong cross section. ·

N. M. G. Process:

F. D. Marshall, 19 Queen Anne's Chambers, Tothill St., Westminster, London, S. W. 1, England.

Harald Nielsen, 13 Firs Ave., Muswell Hlll, London N. 10.

This process is being tested under commercial conditions. details are not yet available.

Perkin Retort:

Dr. F. Mallwo Perkln, 59 Albion House, New Oxford St., · London, S. W. 2, England.

Stationary horizontal type: rectangular cross section, length, 55 feet ; width, 5 feet; height, 8 inches. Shale Is advanced by teeth protruding from the base: teeth are four inches apart, staggered and have a forward, downward, backward, and upward motion: gas fired from underneath; gas and oil vapors removed through series of vents from top of retort under slight suction: feed and discharge continuous.

Universal Retort:

G. F. Bale, 4 Featherstone Bldg., London, W. C., England. Vertical, circular type: Internally gas fired; height, 20 feet; diameter at top, 18 Inches; at bottom, 2 feet 2 inches; feed and discharge continuous; discharge by a ram-forward and backward motion; steam, gas, and air admitted at bottom ; shale broken to 2 inch mesh; gas and oil vapors ·drawn off together at the top.

Wise Continuous Retort:

Wilfred Wise, 36 Victoria St., London, S. W. 1, England.

Stationary horizontal type : length, 180 feet; width, 7 feet; shale ,. broken to half Inch mesh ; shale advanced through retort by means of 25 baffles; throughput, 100 tons in 24 hours; gas fired underneath; gas and oil vapors withdrawn from series of vents under suction; continuous feed and discharge.

Maclaurln Retort:

Robert Maclaurin, Grangemouth, Scotland.

Vertical type; diameter, 4 feet .at the top, 10 feet at the bottom; 30 to 40 tons are put in at a charge and stay in the retort; 48 hours; temperature, 550° C.'; superheated steam injected at the bottom; gas producer gas made from the spent shale.

Burnet Tubular Retort:

Dr. Edward Burnet, 93 Harley St., London, S. W. 1, England.

Vertical type, 26 feet high; cross section oval; long diameter at top, 6 feet; at bottom, 7 feet; short diameter at the top, 3 inches; at the bottom, 5.5 inches; shale broken to half inch mesh; seven annular rings, upper three of cast iron and lower four of refractory material; heat from gas applied externally; temperature regulated; feed and discharge continuous; gas and oil vapors taken of at intersections or rings; steam injected at bottom and half way up; temperature 400° C.; throughput 20 tons in 24 hours; six retorts designed for one bench.

Kimwall Retort:

A. L. Sidney, Care of Joseph Kimber & Co., 23 Philpot Lane, London, E. C., England.

Vertical type, 15 feet high; bulging at the sides; smallest inside diameter, 3.5 feet; largest, 4 feet; construction, in three parts ; Inner section, firebrick, 6 inches thick; middle section fire clay, 4 Inches thick; outer section, ordinary brick, 14 inches thick; no iron used ; shale broken to 2 inch mesh; capacity of retort, 2.5 tons; throughput, 12 tons in 24 ·hours; gas and oil vapors withdrawn at the top; no external heat is applied; superheated steam by the Bynoe system, at a temperature of 500° Fahr. is injected at the bottom and comes in direct contact with the shale. This retort is erected and is being operated for testing shale, at the coal mine of the Ayrshire Coal and Oil Company, near Stewarton, 23 miles from Glasgow, Scotland.

Burney Retort:

Commander C. N. Burney, R.M., C.M.G., 20 Wilton Crescent, . London, S. W. 1, England.

Stationary, horizontal, cylindrical type; thirty feet long; 6 feet in diameter; shale advanced by means of a revolving helical screw; shale broken to 1.5 inch mesh, or less; shale passes between the periphery of the cylinder and the exterior of the threads of the screw; heating gas passes within the ribs of the screw and, by induction, distills the shale; heat controlled by speed at which gas is drawn through; gas and oil vapor is drawn off by suction from six vents; continuous feed and discharge; temperature 550 to 600° F.; 24 hour throughput, 75 tons.

Chiswick Retort:

John Gallon, Supt., Carbon Products and Distillation Co., Church Wharf, Cheswick, London.

Horizontal, cylindrical, stationary type; 25 feet long; 18 inches in diameter; shale advanced by revolution of internal helical screw; shale broken to 1.5 inch mesh; gas and oil vapors drawn from series of vents; gas fired beneath retort; temperature. 450 to 480° c.; continuous feed and discharge; throughput, two tons in 24 hours. The British Government used this retort during the Great War. For nearly a year it was in almost constant use, and hundreds of tests were made with it, yet the retort itself has never been given a thorough test to determine its own efficiency as a commercially successful retort. Its use by the Government was a war measure, merely to determine the oil content of the many varieties of oil shale submitted to it.

Trozer Retort:

C. W. Trozer, 66 Victoria St., Westminster, London, 8. W. 1, England.

Vertical type; height, 10 feet; diameter, 40 inches at the top; slightly larger at the bottom; feed and discharge intermittent; one charge is fully treated and the residue removed before a new charge is put in; time of treatment, 4.5 hours; throughput, 5 tons in 24 hours; gas and oil vapors are removed through a central vertical duct. The peculiarity of this retort is the internal construction, especially the cross section. In order to secure a large heating surface for the shale to come in contact with, and at the same time have a thin layer of shale, the interior of the retort has a series of circular iron sections joined by radial iron partitions. The retort is externally fired and the heat is conducted through the iron to the shale. This retort is erected at Battersea, London, and has been used extensively, especially in experimental work on the low temperature carbonization of coal as well as the retorting of shale.

English Oilfields Retort:

Dr. William Forbes-Leslie, 8 Buckingham Palace Mansions, London, S. W. 1, England.

Vertical type; two chambered; upper tapering section, 11 feet high; lower vertical section, 17 feet high; total height, 28 feet; oval cross section; long diameter, at the top, 2 feet 6 inches; short diameter, 13 inches; slightly larger at the bottom; steam injected at the bottom; externally heated; three separate vents for the withdrawal of gas. and oil vapors from the upper tapering section; throughput, 4 tons in 24 hours. This retort may be regarded as a modification of the present Scotch type; it is under construction by the English Oilfields, Ltd., on its property in Norfolk County five miles south of King's Lynn, England.

Fraser Retort:

William Fraser, Castle Hotel, Downham Market, Norfolk County, England.

Combined vertical and inclined type; three sections; lower vertical, 12 feet high ; middle inclined at an angle of 45°, 10 feet long; upper, vertical, 8 feet high; construction entirely of fire brick and clay; gas and oil vapors taken out in two places from the upper section; continuous feed and discharge; steam injected at the bottom; oval cross section; long diameter four feet ; short-diameter, 9' inches. The purpose in putting an oblique section between two vertical sections is to change the position of the whole body of shale in its descent, break up the column, and thus facilitate the upward passage of the vapors. It may be regarded as a modified Scotch type. It is erected on the property of the English Oilfields, Ltd., five miles south of King's Lynn, Norfolk County, England.

Simpson Retort:

Simpson Process, Ltd., Billiter St., London, England.

Vertical type; 21 feet high ; oval cross section; continuous feed and discharge; iron construction with brick-casing; externally fired; exhaust steam injected at the base ; gas and oil vapors drawn oil at the bottom under a 2-inch vacuum. This retort is erected on the property of the English Oilfields, Ltd., five miles south of King's Lynn, Norfolk County, England.

Freeman Multiple Retort:

Nat. H. Freeman, 9 Southampton St., W.C. 2, Care Educational Pub. Co., London, England.

This retort is of the vertical type and consists of a number of successive chambers one above the other through which the shale passes and is subjected to a successive increased range of carefully controlled heat. The shale is ground to pass a 10-mesh and fed into the first and upper compartment where the temperature is maintained at the boiling point of water to expel the moisture. The shale then passes to the second and next lower chamber where the temperature is regulated according to the product required; e.g., for gasoline, 150°; the material then passes to the third chamber where naphtha is produced at a temperature of 200 to 205° C. The next chamber produces kerosene and the next fuel oil. The maximum temperature reached is 600° Centigrade. The distinguishing feature of this process is the control of the heat by means of the Freeman Precision Temperature Control.

Fell Retort:

John Fell, Managing Director, Commonwealth Oil Co., 117-119 George St., Sydney, New South Wales.

Conclusions

After a two months study of the oil shale industry in England and Scotland, I am led to the following conclusions:

• a. The present Scotch methods are well adapted to the shale treated; they are commercially successful and meet the local conditions.
• b. The Scotch plants are the result of seventy years of operation; they have been improved from time to time, but naturally are not now so arranged as to be highly efficient from an operative point of view, yet it would be folly to scrap them and rebuild in more modern plans
• c. Scotch methods should not be slavishly followed in other countries unless conditions are Identical.
• d. The problem in Scotland is one of operating efficiency - the difference between cost of production and selling price.
• e. The problem in England is not yet a commercial one- but technical.
• f. The presence of an excess of sulphur in all oil shale deposits of England demands that some effective and economical method for the elimination of .the sulphur be devised.
• g. Where sulphur does not occur to an objectionable amount, as In the United States, the serious problem Is the design of an efficient retort.
• h. Many retorts are in process of development. At the present writing, it is virtually impossible for any one (except the inventor himself) to select the best.
• I. In my judgment, the successful retort will be one of three types;
  • 1. The present Scotch type, where local conditions are identical with those In Scotland.
  • 2. A vertical, modified Scotch type, adapted to shale rich In oil, but low in nitrogen content, or,
  • 3. A horizontal type, which will be based on correct scientific principles and be absolutely new.

It is not impossible that successful retorts of all three types will result. The keynote to the successful production of oil from shale is a retort adapted to the character of the shale to be treated.