PETROL FROM COAL

Dominion, Volume 29, Issue 302, 17 September 1936, Page 15

PETROL FROM COAL

Development in England Described HEAVY PRODUCTION COSTS The various processes by which petrol is obtained from coal were described by Mr. W. A. Joiner, of the Dominion Laboratory, in an address to the Technological Section of the Philosophical Society last night. Mr. Joiner dealt chiefly with the hydrogenation process as employed by Imperial Chemical Industries Ltd., at Billingham, England. His conclusion was that economically the erection of large plants eould not be justified. In the first place lie pointed out that no process so far devised would produce petrol at a price comparable with that of petroleum motor spirit,. In Great Britain the average landed cost of petrol was between 3d. and 4d. a gallon, as against a minimum of 6d. a gallon for petrol produced by hydrogenation. This meant that the petrol produced from coal must be exempted in some degree from the usual petrol tax .with consequent loss to the Exchequer. “The petrol production, at Billingham is about 45,000,000 gallons per annum, which means a loss in petrol tax of li million pounds per annum for a period of 4J years if total exemption of the 6d. per gallon tax is taken advantage of,” he said. “At any rate, under present arrangements the. total amount would be £6 750 000. ’“lt ’is 'stated that the extra labour directly and indirectly employed by an undertaking such as this would affect the loss in revenue to the extent of about half this amount by relieving the State of the necessity for providing sustenance for unemployed workers. Economically then it seems doubtful if the erection of large plants can be justified, but unfortunately other aspects have to be considered, such as the necessity for providing supplies of motor spirit in times of national emergency.. Even in this case it is conceivable that large plants of the type required might prove vulnerable objects of attack by air. Too Early to Forecast “All these arguments are based on the present state of development of the industry and it is too early to forecast what may take place in the future. In the meantime money must be spent .and experience gained if such industries are to progress. New Zealand must.be content to keep in close-touch with every development and await with patience the results of experiments being carried out elsewhere. “Technically, there are three ways in which oil can be obtained from coal. These are (1) by carbonisation; (2) Hydrogenation; (3) synthesis from gases produced from coal. “In the case of carbonisation- any oil produced is always in the nature of a byproduct and is not or should not be regarded as the main object of carbonisation. The high temperature carbonisation of coal gives either gas or coke as its main product. The tar is little suited for the production of special liquid fuels such as petrol. Low- temperature carbonisation is concerned chiefly with the manufacture of smokeless fuel or semicoke. “In the second and third process—hydrogenation and synthesis—the major product is motor spirit. The practical application of the hydrogenation of coal is probably one of the most important achievements of modern technology. Coal, if we disregard the physically combined eonstituents such as moisture and mineral matter and also such minor impurities as nitrogen and sulphur compounds, consists of a complex chemical combination of carbon, hydrogen and oxygen. Petroleum consists essentially of the two elements' carbon and hydrogen. “The ratio of "hydrogen to carbon is much higher for petroleum than for coal. The molecules of the coal fcubstance are also much larger and more complex than those in, say, motor spirit. The .process of hydrogenation consists, therefore, in introducing hydrogen into the coal and at the same time reducing the molecular weight from about 2000 for coal to about 100 for petrol. "The main reactions are: (1) The transformation of the coal into hydrocarbons at the same time eliminating the elements, oxygen, nitrogen and sulphur which are got rid of in the form of water, ammonia and sulphurated hydrogen respectively. (2) The addition of hydrogen to the-unsaturated hydrocarbons formed by (1). (3) Splitting' of the saturated hydrocarbons so formed to give the simpler hydrocarbons of. petrol and gas. History of the Process. “The idea of treating coal with hydrogen in this way was first conceived by Dr. Bergius in Germany about 1913. During the war years which followed little development took place, and it was not until 1921 that a semi-industrial plant was erected at Mannheim-Weisena i for treating oil. In 1924 the British Bergius Syndicate was formed, which obtained an option on the patent rights of the Bergius process for the British Empire. British coale were tested out at Mannheim and the results obtained were communicated to the British Government, which decided to commence experimental work at the fuel research station, Greenwich. In 1926 a plant was installed at Greenwich and the work has proceeded since that time, in the meantime the LG. Farbenindustrie had been developing the hydrogenation process independently, and in Germany the process passed wholly into their hands. The first commercial plant was erected by the LG. in 1927. In this year 1.C.1. began experiments. This company applied itself to the solution of the problem of producing motor spirit as the sole product The original Bergius process gave a mixture of oils--petrol, tar acids, heavy oil and pitch. By the end of 1929 1.C.1. had in operation a 10 ton per day of coal pilot plant “The passing of the British Hydrocarbon Oils Production Bill in 1933 added fresh stimulus to development and 1.C.1. decided to construct a full scale commercial plant to produce petrol. The tax on petrol in Great Britain is Bd. per gallon, and this Bill granted the remission of 4d. of this tax for a period of nine years for home-produced motor spirit. If desired the whole of the tax would be remitted for 4j years or proportionately for periods between 4J and 9 years, after which time the matter would receive further consideration. The Billingham Plant. “The Billingham plant of 1.C.1. was originally designed to produce 100,000 tons of petrol per annum, but later was modified to produce 150.000 tons, the extra 50,000 tons to be manufacture! from creosote oil. Construction was commenced in 1933 and the first petrol produced from creosote oil in February, 1935. In June of that year coal was fed into the plant and to-day the works are in full operation. “It is a great tribute to British engineering that since the commencement of operations the plant has continued to operate smoothly apart from minor difficulties Which were only to be expected in a plant of this nature. The total cost of the Billingham plant was in the vicinity of £5,500,000. “The capacity of the plant, which is considered to be the smallest economic unit, is 150,000 tons of petrol. The exact, yield of petrol per ton of coal hydrogenated has not been disclosed, but it is close to 65 per cent, by weight of coal (on an ash and moisture-free basis). The total weight of coal required to produce one ton of petrol, including the coal used ,in hydrogen manufacture and in auxiliary plant, is about five tons. On a new plant this could be reduced to 3| tons. No figures are available yet for production costs, but it seems safe to assume that this would be in the neighbourhood of 7d. per gallon. “The synthetic method of producing petrol is due to Fischer and Ircpsch, of the Coal Research Institute at MulheiniRnhr. This process differs entirely from

the preceding. The reactions are carried out at atmospheric pressure and at much lower temperatures. The raw material for synthesis is a mixture of carbon monoxide and hydrogen. These can be produced from coke in the form of blue water gas which contains roughly equal volumes of these gases. In the hydrogenation process the complex coal substance is broken down in stages with the addition of hydrogen to form the simpler molecules composing motor spirit. In the synthetic process, the coal is very largely decomposed into its elements and these recombined with hydrogen to give the desired product, "Industrial development of the Fischer process has been possible only within the last two years or so. There are no industrial plants in Great Britain, although in addition to investigations at Universities and at the Fuel Research Station a private company is carrying out research on the synthetic process”