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Synthetic Oil Production in Germany
Interrogation of Dr. Butefisch
British Intelligence Objectives Sub-Committee
Interrogation of Dr. Butefisch at the Ministry of Fuel &
Power January, 1946
BIOS Item 30
Fuels and Lubricants
Interrogation on 2nd January, 1946
Dr. Butefisch was interrogated by the following :
Major K. Gordon
Dr. R. Holroyd
Dr. J.N. Perquin
Mr. D. Morten
Mr. D.A.C. Dewdney
Mr. A.R.M. Murray
Mr. K. Stock
Dr. F.A. Williams
General Survey of Synthetic Oil Production in Germany
Dr. Butefisch was asked in the first place to give an outline of
the production of synthetic oil in Germany. Dr. Butefisch referred to the start
of production in 1927 at Leuna with an output of 300,000 tons per annum at
first, subsequently increased to 500,000. It was intended that half of the whole
of the oil used in Germany should be synthetic. In 1934-1935 under the
"Vierjahres Plan" there were started up additional plants in the
Difficulties with the hydrogenation of black coal delayed the erection of plants for this purpose, but ultimately the treatment of the black coal was commenced at Scholven and Gelsenberg. These were followed by the following synthetic oil plants Wesseling, Poelitz, Ruhrchemie, Hoesch and Essener Steinkohle.
Dr. Butefisch gave figures indicating the rapid increase in the total production of oil from synthetic plants and natural petroleum during the war years from 4,300,000 tons in 1940 to the maximum attained of 7,100,000 in 1943. He was subsequently asked to prepare a table showing details of the various grades of oil produced throughout the war in Germany.
Dr. Butefisch pointed out that of the 1943 production of oil the Fischer Tropsch process accounted for 430,000 tons as compared with the 3,400,000 tons produced by hydrogenation.
Poelitz had been the highest producer of iso-octane; Leuna had also contributed; Moosbierbaum had produced alkylate, DHD-benzine and also hydro forming benzene.
Natural petroleum was responsible for the greater part of the production of lubricating oils. Special synthetic lube oils were obtained from the polymerisation of olefins produced from Fischer-Tropsch wax, brown coal tar wax and petroleum wax and by the synthesis of Ester oils. The total production of synthetic lubes was only some percent of the total lubricating oil, to which shale oil contributed a proportion. Plans had been made for the development of oil produced from the latter, but no great success had been achieved. The total production of shale oil for 1943 was 109,000 tons.
The Blechhammer hydrogenation plant was not finished and alkylate plants at various hydrogenation and Fischer Tropsch works were also unfinished. It seemed possible that these may not have been needed since the development towards the use of turbine engines called for a fuel more like diesel oil.
Blending of the aviation gasoline was carried out by the Luftwaffe; the plants supplied only base petrol. In the last year they had tried monomethyl aniline or ordinary aniline since the production of lead tetra-ethyl was doubtful.
Comparison of Fischer Tropsch and Hydrogenation Processes.
Asked why the hydrogenation process had developed to a much greater extent than the Fischer Tropsch, Dr. Butefisch replied that the raw material requirements for the Fischer Tropsch process were appreciably higher than for hydrogenation. The Fischer Tropsch motor fuel was also too low in octane number, 40-45. The diesel oil was of course very good. Dr. Butefisch was understood to say that the Fischer Tropsch oils were more expensive than hydrogenation oils both in capital and running costs, but he undertook to supply figures comparing the two processes. By and large he thought Fischer Tropsch oil was some 20% higher in cost than hydrogenation oils both in capital and running costs, but he undertook to supply figures comparing the two processes. By and large he thought Fischer Tropsch oil was some 20% higher in cost than hydrogenation oil, and quoted figures of 32 pf. per kilo of oil by the Fischer Tropsch process as compared with 24-25 by the hydrogenation process. The isomerization of the straight chain paraffins in Fischer Tropsch product was not as easy as was thought at the time. In his view, the Fischer Tropsch should be regarded as a chemical process yielding pure hydrocarbons, and was therefore, one for the chemical rather that the fuel industry. He mentioned that some 80,000 tons per annum of Fischer Tropsch diesel oil was converted to soap by sulphonation; lubricating oil was made from the wax. He regarded the Oxo process as very interesting. The variation in the Fischer Tropsch products obtainable by choice of catalysts and conditions made the Fischer Tropsch process very flexible.
Hydrogenation on the other hand was mainly suitable for making benzine, diesel and fuel oil, but not for making chemicals. In connection with the hydrogenation of Upper Silesian coal, Dr. Butefisch appeared not to think these were any more difficult to treat than Ruhr coals.
When questioned about the operation of the Blechhammer hydrogenation plant to produce an excess of distiallate heavy oil at a very high throughput, some three times the normal, Dr. Butefisch said that it was desired to obtain fuel oil- a material which under normal conditions it would not be worth while producing by hydrogenation. Consideration appeared not to have been given to the use of any liquid phase stage to treat this heavy oil for conversion into middle oil.
Methyl Alcohol for Motor Purposes.
Dr. Butefisch referred to experiments which had been carried out using fuels containing methyl alcohol. He referred to the difficulty with water tolerance and to the fact that the total consumption of an engine using a fuel containing 15% of alcohol was no higher than with the petrol alone.
Methyl alcohol was not used as a fuel during the war because it was wanted for other purposes. It was pointed out to Dr. Butefisch that methyl alcohol plants were cheaper than hydrogenation plants, but Dr. Butefisch said that the gas consumption involved in the production of the alcohol were much the same as by other synthetic methods.
High Octane Number Fuels
Dr. Butefisch said that octanes were being made pre war at Leuna and Poelitz. In the former case isobutanol was the starting material
Production of aviation spirit at the start of the war was low because the Luftwaffe up to 1938 was not worried about high octane numbers; they were prepared to blend with benzol. When the Luftwaffe demanded higher octane numbers as a result of pressure from engine designers, iso-octane was made from isobutanol. The hydrogenation petrol had an octane number of 78-79 and with iso octane or alkylate addition, numbers of 102-104 were achieved. All the aviation gasolene came from black coal. The cost of iso-octane from isobutanol was said to be 80-90 pf. per kilo. In 1941 isobutane was dehydrogenated to isobutene, polymerised to iso-octene and hydrogenated. Later isobutene and butane were alkylated. There was, however, difficulty with supplying the isobutene. Leuna was the first to make alkylate.
With regard to the D.H.D plants built at several works but not put into operation, it was said that this delay was due to the influence of the development work being carried out on turbine engines, coupled with the use of aniline which showed that it was not necessary to have D.H.D. petrol, and in addition the loss of production of 20% resulting from the D.H.D. processes was serious with the declining output from the synthetic plants. It was pointed out to Dr. Butefisch that alkylate plants were still being increased at the end of the war but he inferred that there was insufficient co-operation between engine designers and the Luftwaffe.
Dr. Butefisch was in agreement with the statement made to him that the aromatic content in the D.H.D. petrol from black coal was too high for the utilisation by any engine which was in existence. Junkers were also of this opinion. High load content in the fuel had no injurious effect on valves when using aniline.
Jet Engine Fuel.
Dr. Butefisch said the supply of jet engine fuel was a simple problem but the Germans had made it complicated. A pour point of - 20ºC was necessary to avoid blockage of the fuel lines. Actually the fuel consisted of black coal middle oil from the sump phase, which had been put through the gas phase at 320-330º C and was mixed with heavy spirit.
The products from both the T.T.H. and M.T.H. processes at Zeitz could be used for gas turbines. These two processes serve to give paraffins and lubes, although the lube oil was not good. There was no incentive to make diesel oil since the return was only 16 pf. as compared with 32 pf. for the spirit.
Dr. Butefisch said it had been proposed to erect in Hamburg in pre-war days a plant for the catalytic cracking of petroleum oil combined with hydrogenation. At the end of the war there were proposals to use petroleum oil fractions or middle oil from hydrogenation to make motor fuels with a silica fixed bed catalyst.
Lubs Oil Production
Dr. Butefisch admitted that insufficient dewaxing and solvent refining equipment was available in Germany to make good lubricating oils. The wax was needed and it was intended to erect more plant. The ethylene synthetic oils and S.S. oils helped to overcome the difficulties with cold in Russia. Poelitz made use of Fischer-Tropsch wax for producing synthetic oils, whereas Ruhrchemie appear not to have been successful. He thought that the matter may have some paternal difficulties. The synthetic Ester lubricating oils were prepared by blending the ester from adipic acid and isobutanol with ethylene synthetic lubricating oil. The quality of the blend could be varied by varying the proportions of the mixture. Special lubricating oils were used for the Panzers.
Interrogation on 9th January, 1945
The interrogation of Dr. Butefisch was conducted by:
Sir Harold Hartley
Mr. O.F. Thompson
Dr. W.A. Macfarlane
Mr. A.R.M. Murray
Dr. F.A. Williams
In the first place Dr. Butefisch was asked to give an account of his activities in connection with the oil programs in Germany. Dr. Butefisch related how in 1920 he had been in charge of all new technical processes at Leuna. He later became a Director of the I.G. Farbenindustrie. He was a Founder-member of the Wirtschaft- gruppe Kraftstoffe, which was formed in 1926/27 by Industry although its leader was a Government nominee. In the course of the war Dr. Butefisch had succeeded Dr. E.R. Fischer as head of this organisation. Dr. Butefisch mentioned that he was also a Director of Brabag and was also interested in the Poelitz plant and other organisations.
Hydrogenation had been started at Leuna in 1927 and the output which in 1930/31 had been about 100,000 tons per annum had soon been pushed up to 300,000 without any increase in plant. The final maximum obtained at Leuna was 600,000 tons per annum. In 1935/36 the Vierjahresplan was prepared and the Brabag Organisation set up with capital which was not provided by the Government. Other plants were subsequently erected in which, however, there was Government assistance for example the Havebrack and Auschwitz plants were I.G. Farben enterprises financed with Government money. Both these plants were projected after the commencement of the war. The I.G. Farben enterprises financed with Government money. Both these plants were projected after the commencement of the war. The I.G. Farben did not have an interest in the Blechammer plant which was set up by a syndicate of Silesian coal owners with, however, Government money. The reason for I.G. non-participation was that the I.G. felt that they had gone as far as they wished to go in investments in synthetic oil plants. Butefisch claimed that he had no knowledge of the projected synthetic oil plants at Glanbeck and Frankenthal and therefore he did not think they could be I.G. Farben projects.
The I.G. had several interests in the possibilities of developing fuels and chemicals from petroleum. It has a plant at Moosbierbaum.
In addition to hydro-forming there was at Moosebierbaum a D.H.D. plant. The subsequent addition of crude oil distillation plant was an emergency measure to provide additional refining capacity undertaken at the direction of the Reichamt under Dr. Krauch.
Dr. Butefisch said that he personally thought the war was not going to be won by Germany after Stalingrad, but it was not possible for the realisation of this by I.G. to make any change in their policy.
Effect of Air Attacks.
Dr. Butefisch was unable to say when the shortage of oil was really felt because the position regarding attacks in Germany was always kept a close secret. He was, however, aware of the severe decline in production as soon as the May 1944 bombing of the synthetic oil works started. Up till then there had been no anxiety felt about oil supplies.
According to Butefisch the damage to communications did not seriously interfere with oil production except in the case of the Ruhr plants where rail dislocation hampered production at Scholven and Gelsenberg. In general, the effect of the bombing of communications had only a secondary effect on oil production. The actual bombing of the plants was far more important. Butefisch stated that he was astonished at the rapidity with which bomb damage to railway tracks was repaired. At one time a shortage of railway tank wagons became imminent but this was unexpectedly relieved by the shortening of communications due to the retreat in Russia, and from then on there was an abundant supply of tank wagons.
The damage to communications did not, in general, prove a serious factor in the repair of plants. He felt that any delays in the completion of repairs were due more to lack of materials caused by the muddled priorities of the Geilenberg programme than to difficulties in transporting materials.
At the start of the war aviation fuel consisted of normal gasoline plus iso-Octane prepared from isobutanol. Some 6/7,000 tons per annum of iso-Octane was manufactured. Benzole was also used to bring up the octane rating of the fuel together with up to 0.7 c.c. per litre of Lead Tetra-Ethyl. Aromatised spirit of O.N. 78 prepared from spirit of O.N. 68 by hydrogenation treatment using Tungsten Disulphide was also employed to be followed later by D.H.D. Spirit.
Prior to the war it was intended to use butane for the manufacture of synthetic rubber. The planning of the use of butane for alkylate production was left too late in the war since the plants were not finished. Only the plants at Leuna and Poelitz were completed. The curve for the production of iso-Octane rose very slowly and the maximum reached was only 50,000 to 60,000 tons per annum. In 1944 there was talk of alkylete not being required since spirit of O.N. 74/75 plus 0.12 c.c's per litre of lead with the addition of aniline or bono methyl aniline gave a satisfactory fuel with no attendant corrosion problems.
Dr. Butefisch was concerned only with the subject of base petrol and D.H.D. petrol. Special blends were prepared by the Forces for particular uses, e.g. motor transport, bombers, fighters, and the blends employed were not secret.
The D.H.D. process was really equivalent to the hydro-forming process except that it worked at some 50 atmospheres pressure instead of 25 atmospheres pressure. It gave a spirit of C.N. 78/82 but with a loss of some 15/20%. Attempts have been made to pass Fischer Tropsch spirit through the D.H.D process but have met with difficulties.
Dr. Butefisch said that there was no shortage of lubricating oils. The bulk of the lubricants came from the German and Austrian petroleum which contained a large proportion. There was, however, insufficient de-waxing equipment available because of the large proportion of wax in the crudes.
Special lubricants for aero-engines were made from the polymerisation of ethylene, the source of the ethylene was usually by-product ethane obtained through hydrogenation. These synthetic lube oils possessed very good qualities and were used in blends with natural oils. Ester lubricating oils were also made synthetically from the ester of adipic acid and isobutanol. Synthetic lubricants amounted to only 10% of the total lubricants.
Fischer Tropsch Process.
Dr. Butefisch said that the I.G. were very interested in syntheses starting from carbon monoxide and hydrogen mixtures in order to make alcohols, pure hydrocarbons, etc., but not as a means of making fuel. All Fischer-Tropsch plants had worked to their maximum capacity but not by any means did the whole of the product go to fuel uses. Much use had been made of fractions by the Chemical Industry, for example, the use for soap had amounted to 70,000 tons per annum. He mentioned that at Schaffgotsche trouble had been experienced with medium pressure operation. At Schwarzheide there had been trouble with the gasification of brown coal as well as difficulties with the synthesis. The Lutzkendorf plant had always been in difficulties with the gasification and gas purification and had actually produced little oil during the whole war.
The cost of the Fischer Tropsch process was stated to be some 20% higher than that of the hydrogenation of coal for the production of spirit. It was possible by the Fischer Tropsch process to produce a highly unsaturated product but the unsaturated hydrocarbon had the double bond in the centre of the carbon chains whereas it was preferable to have it near the end of the chain. He regarded the C8 to C20 hydrocarbons as the most important range for the production of chemicals for use in textiles, solvents, washing materials, lacquers.
At Poelitz paraffin wax from the Fischer Tropsch process and from T.T.H. and M.T.H. processes at Zeitz were cracked and used for the manufacture of lubricating oils. It has been intended to erect a Catalytic Cracking Plant at Niedersachswerfen since the process gives a good aviation spirit from petroleum.
Arising out of the earlier of the above interrogations Dr. Butefisch was asked to supply written information on a number of points. These points were subsequently incorporated in a questionnaire. In the ensuing section the questionnaire and Dr. Butefisch's reply are given in full.
Ministry of Fuel & Power
7, Millbank London
At the meeting last Wednesday, it was arranged that you would
provide this Ministry with information on the following points:
(1) The relevant costs of production from black coal per ton of motor fuel by the Fischer Tropsch and hydrogenation processes.
(2) The relevant qualities of coal required to produce a ton of motor fuel by the two processes.
(3) An account of the manufacture, properties and use of the Ester synthetic lubricating oils.
(4) Oil production figures for Germany during the war period.
It is now desired that you should elaborate upon the above points, so as to include the following additional information. Any explanation required to make the figures precise and to avoid misinterpretation should be included.
(A)(i) Under (1) above the cost figures quoted should be those actually achieved under good running conditions. A similar set of figures of estimated cost in the case of a new specially designed plant should also be included if they differ from the realised figures.
(ii) Fischer Tropsch Process.
The figures for the costs should be given for both one metric ton of primary product and for one ton of motor fuel, using as raw materials brown coal or coke from black coal. The proportion represented by operating costs should be shown and details given of the capital and other costs.
Figures should be given per metric ton of motor fuel which apply to the use of each of the following raw materials:
Black coal, black coal tar, pitch, producer tar, brown coal and brown coal tar.
The prices taken for each of these raw materials should be shown and operating costs and capital costs etc. should be differentiated.
(B)(i) Item (2) above should be extended in the following manner:
(ii) Fischer Tropsch Process.
The quantity of coal required to give one metric ton of primary product and one ton of motor fuel from both brown and black coal should be given. Details should be shown separately of the amounts of coal required to produce the necessary synthesis gas, and one of the energy and power requirements.
The figures should show separately the coal requirements for actual conversion to oil, and in addition the coal requirements for the necessary hydrogen and lastly the coal equivalent of the energy and power requirements. Figures should be given for the hydrogenation of both black and brown coal. Finally figures should be quoted for the amounts of brown coal tar, black coal tar, pitch, producer tar and petroleum residues required to give one ton of motor fuel and likewise the coal (expressed in terms of black and brown coal) required to produce the necessary hydrogen should be shown, and in addition the coal required for energy and pwer.
(C)(i) Item (4) should show the overall production from the various sources for each of the war years 1939-1945 for the following products:
Motor spirit, aviation base inclusive of D.H.D., diesel oil, fuel oil, lubricating oil, treib gas, alkylate and octane, kerosene, miscellaneous.
(ii) The year by year production of each of these products from the various processes, Fischer Tropsch, hydrogenation, brown coal tar distillation, bituminous coal tar distillation, petroleum, benzol etc., should be given. Finally the production of each plant of these various products should be given.
(iii) Details should also be given of the extent to which it was proposed to extend the capacity for the above products at each of the above plants, and of the dispersed plants proposed under the Geilenberg plan.
Information is also required on the following points:
(D) In the hydrogenation process was there any preferences for any particular raw material in order to produce a specific product, or was the choice merely one of the most appropriate operating conditions.
(E) The I.G. carried out experimental work on four hydrocarbon synthesis processes using iron catalysts.
(i) Which of these is regarded as the most promising ?
(ii) Was any one of the processes developed sufficiently for full scale production?
(iii) Was there any intention to carry out full scale development?
(iv) What were the estimated costs for the fixed bed high recycle process?
(v) Did the processes of (iv) give a spirit of octane number as high as 80, and if so was this due to isohydrocarbons?
(vi) Who in the I.G. organisation is the best authority on the Fischer Tropsch work carried out by the I.G.
The questions set out in the document of the 4th January by the Ministry of Fuel and Power are concerned mainly with a comparison of the Fischer process with the hydrogenation process, and involve the consideration of range of various manufacturing possibilities. The exact evaluation of these figures in a form capable of withstanding any criticism would require information on each single operation in the processes, with all the specific consumption figures and detailed cost calculations. These figures are not at my disposal here, and I have no notes or documents on the matter. The copious documentary material was, when last heard of, at Leuna.
For comparing processes and for the technical and scientific consideration of both projected and existing plants, I developed and built up at Leuna in 1926 the Abtailund fur Wirtschaftlichkeitsprufung (Department for the Examination of Economics), which thereafter worked on many I.G. projects.
The establishment had as its object the examination of scientifically investigated reactions and processes which had been worked out on a semi-technical scale, with a view to determining their economic practicability before they were employed on an industrial scale. Such examination can only be undertaken by personnel who, as a result of the best scientific training and several years practical experience in various processes, have powers of observation and critical examination, and further, know how the products prepared in the processes should be examined and judged from the commercial standpoint (market analysis).
This Department had therefore to undertake the following main task:
(1) Testing the scientific and technical bases of the processes.
(2) Preliminary calculation of the cost of production of the products, in accordance with the generally valid rules of experience.
(3) Market analysis of the products.
(4) Comparative calculation of the existing manufacturing processes with the same or similar end products.
(1) The theoretical bases of the process under consideration were worked out (thermodynamic conditions, theoretical yield, heat consumption etc.) The technical details were then discussed (e.g./questions of plant, corrosion, temperature, pressure, other conditions etc.)
(2) After the questions under (1) were thoroughly clarified and after the quantities of raw materials consumed were determined, a preliminary calculation of the production cost of the product is made. The following data are determined according to the generally valid rules of experience, bearing in mind any special conditions, such as may arise, for example, from the situation of the plant:
(i) The price of the raw materials to be used including transport costs.
(ii) Power costs for steam and electricity according to the various prices for coals and the various possibilities for current generation. (High or extremely high pressure steam, condensation or counter-pressure, price of water, facilities for the utilization of gas and the general price configuration).
(iii) Costs of necessary chemicals.
(iv) Wages (wages/man/hour) for working the process.
(v) Wages for repair work. These are calculated according to special rules from other comparable chemical industries (e.g. fitter-hours for low-pressure or high-pressure plant-water-gas production or salt works inclusive of materials consumed-etc.)
(vi) Necessary bonuses on wages.
(vii) Conditions of employment of skilled and unskilled workers (from experience with related processes).
(viii) Determination of the capital charges-the overall value of the plant according to the data from the constructional engineer's office (necessary for making comparison)-calculation of the necessary amortisation (life of the plant) and calculation of the necessary interest payments-taxation questions.
(3) The market analysis is carried out in collaboration with the commercial departments (purchase and sales). It includes an examination of the prices of like or related products already on the market, import and export questions, customs duties and special payments, questions of demand and comparisons of quality, and of the development of markets.
4. If like or similar manufacturing possibilities exist, a comparison of the cost of production of these products is drawn up considering the various cost factors separately. At the same time, other processes in course of development are compared with the process under investigation in so far as the same or similar end products are in question.
The calculations as a whole give a general picture of the the possibilities of utilising a process, and, on more prolonged observation, a constant comparison with other like or similar processes already in existence. They allow analyses of the individual stages of a process to be made, and the fixed and variable costs to be separated. In this way, the examination of the economic practicability gives constant stimulation and direction in seeking possibilities for the improvement and development of the process. For drawing up the cost calculations for a process the data mentioned above are necessary, together with the material on which they are based, and this applies particularly for the comparison of processes.
Explanation of Table I
The data are estimated from figures in my possession for the actual operation of both types of plant, but I have not here at my disposal the accurate data on which they are based. The individual items are composed of a series of single values (see Introduction). They give an approximate picture for the comparison of large plants (capacity, for hydrogenation, ca. 150,000 t., for Fischer ca. 100,000 t./year).
(2) The comparison is made on the basis of 1 tonne (1000 kg.) liquid products in the case of the Fischer process, but on the basis of 1 tonne motor spirit in the case of hydrogenation. Thus we are concerned with different end products in comparing the coal consumption and total cost, as these final products have different values. It is therefore essentially, only a comparison of processes. The further evaluation is followed up below.
(3) For the Fischer synthesis a yield of liquid products of 130t./cu.m. ideal gas is assumed which is based on the results of the Schwarzheide plant with a good catalyst.
(4) Apart from the fixed costs, the total cost is very markedly dependent on the quality and price of the new materials (analysis of the coal, method of generating energy).
(5) The energy requirements can only be estimated roughly and the use of waste heat, waste gases, etc. can cause changes from the estimated value.
As far as coal consumption is concerned the two processes show no essential differences, but it is to be noted that more of the coal used by the hydrogenation process is used for power production so that cheaper coal can be used (coal dust or waste gases). An essential part of the Fischer synthesis is the preparation of water gas and synthesis gas and this determines the high coke consumption. Although synthesis gas can be prepared from methane either by a purely thermal treatment or by a catalytic process, this, according to our technical results, offers no advantage, if one compares the methane with the calorific value of the coal and uses an equivalent amount. The size and the cost of a Fischer plant are therefore to a large extent determined by the large synthesis gas plant necessary and the cost of preparing the synthesis gas. This forms about 50% of the total price of the plant.
In the case of hydrogenation the final product is motor spirit, which, starting from bituminous coal, has an octane number of about 74-78 without further treatment. The process is flexible in that it can be made to give diesel oil and fuel oil by using a greater throughput; there is a corresponding diminution in the consumption of hydrogen. And either tar or pitch may be used as raw materials. If Fischer products are to be altered by cracking the middle oil and wax then additional costs and losses are involved and the process must be rejected as uneconomic. The octane number of the spirit can be improved from its normal value of 58-60 by isomerisation over new catalysts, but as far as I know, this has not yet been developed into a technical process.
Medium pressure synthesis from carbon monoxide and hydrogen with cobalt, and also with iron or mixed catalysts, has in the first place a much higher cost on account of the compression of all the synthesis gas to about 20 atm. Working so as to obtain saturated hydrocarbons, the total yield of liquid products is not increased. It is possible to conduct the synthesis so as to obtain higher yields of wax, but this always means decreasing the gas velocity. The conditions can also be altered-by altering the gas composition, temperature or catalyst-so as to obtain a greater proportion of unsaturated hydrocarbons in the products, or to obtain a mixture of unsaturated hydrocarbons, aldehydes, ketones, and alcohols. The separation of these mixtures is very difficult and has not yet been solved on the full scale.
The project for conducting the Fischer synthesis so as to produce mainly unsaturated hydrocarbons and then to convert these in a separate process the Oxo-synthesis- by the addition of CO + H; into aldehydes and then into alcohols or acids has been studied from many angles and a full scale research plant has been built. The economics of this process is very questionable because the price of the olefins is at present too high and no satisfactory technical solution of this problem has been forthcoming (such as simple cracking of waxes).
Medium pressure synthesis, and also synthesis with iron or mixed catalysts thus appears to have a position intermediate between synthesis or pure paraffin hydrocarbons and of pars alcohols. For example, in the position of the double bond in the unsaturated hydrocarbons of in the branching in the long chain paraffins.
Use of the Synthesis Products for Chemical Purposes
The synthesis products are chemically pure and as a result they offer possibilities for the preparation of:
(1) Fatty acids (from wax by direct oxidation or by way of the Oxo-synthesis. Price of Wax.
(2) Lubricating oils (by cracking the wax or lower fractions and polymerisation)
(3) Alcohols (see Oxo-synthesis, -Isoalcohols, Yield)
(4) Detergents (Sulpho-Chlorination of the 260-320ºO fraction. Alcoholsulphonates)
(5) Materials for the Textile Industry (See Oxo-synthesis)
(6) Softeners (Sulpho-chlorination & Phenol; and other ways)
The question then arises as to whether the CO & H2 synthesis should be used as the basis for these and other similar processes. In judging this, a series of other alternative possibilities must be considered, and the separation of individual fractions from the total synthesis product is also of fundamental importance for the calculation. In my own opinion, the Fischer process is a process for obtaining pure chemical substances as starting materials for further synthesis. It must therefore, in the first place, be compared with other chemical processes which serve the same purpose. In my opinion, it is not very suitable, under normal conditions, for the production of the usual motor fuels, as it has not sufficient flexibility, and, as compared with hydrogenation, is too expensive.
I cannot answer the detailed question under (i) and (ii) nor B (i) and (ii) without documents. Only approximate answers can be given, and it must be also born in mind that here, in particular, alterations in the composition of the raw materials used have a big effect. Differences in the analysis of one brown coal from another, and differences in the analyses of the tars, according to whether they have been produced by direct or by indirect processes, lead to differences in the consumption data even for hydrogenation. For the Fischer process the method of gasification of the brown coal briquettes is important - Koppers, Didier, or Schmalfeld processes - as here not only the consumption of raw material but also the capital cost varies.
Thus I can only give a rough comparison between the various possibilities, which however allows the fundamental differences to be appreciated. Documents concerning the details of these comparisons are to be found at Leuna. But at the moment I am still engaged in writing out the rough comparisons.
The consumption figures for the Fischer synthesis for the production of synthesis gas or water gas from coke, on the one hand, and from brown coal on the other, are very different because several different processes for gas generation are in use - the Koppers, the Didier and the Schmalfeld- and the capital costs of these plants are very different. The Schmalfeld process, used at Schwarzheide and Lutzkendorf (It was not used at Schwarzheide ! Translator) lead to no useful technical improvements. Briquettes with a water content of about 15% were used. The absolute coal consumption, calculated back to bituminous coal, should lead to the same figure, but it was, in part, 15-20% higher. I have no accurate data for the specific coal consumptions available, they are in the documents at Leuna. However, so far as the costs of the final products are concerned it can be said that this is about the same as for plants using coke from bituminous coal. This evening out is due to the smaller price of brown coal as compared with bituminous coal.
I have no data with me for the individual consumptions and analyses of the various raw materials for hydrogenation, brown coal, tar pitch and petroleum resides. Even the brown coals differ among themselves in carbon, hydrogen, and oxygen content so that the specific consumption figures will be different. Thus, the tars have also corresponding different properties, and these further depend on the process used in making the tar. The direct and indirect processes differ very much in this way and the tars from behave differently. At Leuna the following raw materials, among others, were said:
(1) Brown coal generator tar
(2) Brown coal low temperature carbonisation tar
(3) Bituminous coal tar middle oil
If petroleum residues or pitch alone are used then a pressure of 700 atms. for the liquid phase process is necessary. The evolution of reaction heat is not sufficient to allow petroleum residues to be hydrogenated at 200 atm.; in the case of pitch the breakdown is not sufficient.
For the hydrogenation of pure brown coal tar, as is done, for example, by Brabag, the price of the tar is so fixed that the price of the final products is the same as for the hydrogenation of brown coal. In the case of brown coal low temperature distillation tar this price is 78-85 R.M./t., and for generator tar 40-50 R.M./t. Low temperature tar from bituminous coal did not come into question as the amount available was so small only research scale working. Pitch was valued at 40-50 R.M./t. for hydrogenation. As already explained, only very general figures can be given for the consumption of the raw materials, approximate, estimated, figures being:
These figures do not add to approximately 100-Translator. It is not noted that the motor spirit from brown coal hydrogenation has an octane number of 69-72 and that obtained by the hydrogenation of brown coal tar has a rather lower value.
I have answered question 3 on lubricating oils and also C and D from my documents as far as they go, and for the rest, from memory.
An account of the manufacture, properties and use of the Ester synthetic lubricating oils
Work on synthetic lubricating oils at Leuna had as its object the development of economically possible processes for preparing synthetic oils with properties as good as or better than those of natural lubricating oils of petroleum origin. Two types of oil were prepared.
1. Ethylene Lubricating Oils. These are prepared from waste gases from hydrogenation or from ethylene made from ocetylene or alcohol. Production at Leuna: 10,000 t/year. Production cost taking 20 amortisation and using ethylene at 43 Rpf/kg : 85 Rpf/kg. Properties: high thermal stability and good freezing properties.
2. Ester-oils. The ester lubricating oils are mixtures of ethylene lubricating oils (also using fore-runnings) with esters of adipic acid, the esters used being those of the higher alcohols from the isobutylol plant. Frequently the higher boiling fraction (over 160ºC) C8-C14 iso-alcohols were used.
The mixtures were used for
(1) Aircraft Oil using 60% ethylene lubr. oil, 40% ester
(2) Motor Oil " 60%" "40%"
(3) Railway Axle-oil using 80% ethylene lubr. oil, 20% ester
(4) Machine oil using 75% (fore runnings) lubr. oil 25% ester
(5) Aerial torpedo oil using 40% ethylene lubr. oil 57% ester (+3% anti-corrosion component)
(6) Axle-oil using 60% residues ) ethylene
20% fore-runnings ) lubricating oils, 20% ester
The production data for the war years are given in Table II, III & IV insofar as I have them here at my disposal. They are essentially figures for the delivery of products and so cannot differ any more than a few per cent from the true production figures. The total capacities of the plants are shown in Table V. I have no figures with me for the production of alkylates and octane, and corresponding footnotes are made in Table II (they are not Translator) The total extensions according to the Krauch and Geilenberg programme can only be estimated here because I have no accurate data for the. It was planned to extend .
The idea of the Geilenberg Programme was to effect these extensions, to remove existing plants to safe underground sites and to split up large plants into a number of small units. From memory (I have no notes at my disposal) there were to be
(1) 4 Hydrogenation Plants (underground)
(2) 3 + 2 Topping and Lubricating oil plants (underground at Ebensae, Porta and Deutsch Brech
(3) 2 + 40 Cracking and Topping Plants (small pipe-still Topping Plants, each 3,000 t/month)
(5) 1 Catalytic Cracking Plant and D.H.D. plant (Niedersachwerften)
(6) 1 Catalyst Plant.
(Translators Note. Table III gives motor spirit production, whilst Table IV shows total production and aviation spirit production. The periods shown as I, II and III respectively are of 4 months although the figures are given in tonnes per month. The difference between total monthly production and the sum of aviation and motor spirit represents the diesel fuel production.)
(i) The researchers of the I.G. on hydrocarbon synthesis were concerned with:
1. Finding a cheaper substitute for cobalt catalysts because of the expense of regenerating them and the shortage or cobalt. Work was done with iron, manganese, and various mixed catalysts under normal Fischer conditions.
2. Examining the yields obtainable at medium pressure for different catalysts.
3. Working in a liquid medium with the catalyst suspended in the liquid.
4. Working in a liquid medium with the catalyst arranged in a fixed bed and using a high rate of recirculation.
All these researchers were done with a series of very different catalysts, in particular with iron and mixed catalysts. The composition of the synthesis-gas was varied and water-gas was also tried. The effect of temperature and pressure was studied. The aim was:
1. To increase the catalyst life. In this connexion researches on Regeneration were also carried out.
2. To improve the yield.
3. To prepared unsaturated hydrocarbons which could be worked up in other chemical processes.
4. To increase the yield of higher paraffins.
(ii) All these researches had not yet reached the technical research stage. Success was met with for iron and a series of mixed catalysts in obtaining rather higher yields, calculated on (CO + H2) and also higher yields of wax, up to about 65%. With iron, and above all, with manganese catalysts, a large proportion of unsaturated hydrocarbons is also obtained, but they are always accompanied by products containing oxygen, such as aldehydes, ketones, etc. Attempts to alter the position of the double bond in the unsaturated hydrocarbons by making alterations in the process were not successful. And in these processes there is a great difficulty in separating the products. The liquid phase process with water-gas has not yet been developed to the full technical-research scale on account of the large amount of oxygen products produced. The same is true for the process in which the liquid medium is circulated over a fixed bed of catalyst. In this case various isomerisation catalysts were introduced and an increase of iso-compounds was observed (but I cannot remember the results in greater detail.)
(iii) The I.G. had no intention of creating a large plant based on any of these researches because examination of the plant and production costs according to the results obtained up to now show that this would be uneconomic. These researches however, especially those concerned with the production of olefines, ought to be continued to obtain a comparison with other possible methods of working. Such researches are also necessary in order to obtain suitable starting material for the Oxo-synthesis, such materials being otherwise not obtainable.
(iv) To the best of my memory, cost estimates have not yet been made for the fixed-bed liquid phase process as no firm figure for the yield can yet be given as the experimental results are not sufficiently well repeatable.
(v) Yields in these researches were very variable but the highest octane number was about 80.
(vi) For Leuna: Dr. Herold (now in Leuna) For Ludwigshafen: Dr. Weitsel ( to the best of my knowledge now in Ludwigshafen.)