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RESULTS OF HYDROGENATION RESEARCH WORK IN THE PAST TEN YEARS IN THE LABORATORY OF CHEMICAL ENGINEERING OF DELFT UNIVERSITY By Prof. H. I. WATERMAN, Ph.D., HOn.M.Inst.P.T.
.' HYDROGENATION processes are often combined with destructive hydrogenation. If we have only to do with pure hydrogenation, then the velocity of the process in connection with the capacity of the plant is of the utmost interest.The quality of the hydrogenation product in this case is completely settled, and needs no further investigation.If there is destructive hydrogenation, a new factor of uncertainty is introduced. The quality of the reaction product is not known before, and must be determined. Therefore it was necessary to work out methods that allow us to determine the average number of rings per molecule.Thus the ring formation or eventually the ring opening can be measured quantitatively.The method is a purely physical one, so that the products are not maltreated, e.g. by strong sulphuric acid treatment. One of the advantages of the new method of examining mineral hydrocarbon mixtures is, among others, that the paraffinic sidechains are not neglected, e.g. asopropyltoluene is not a pure aromatic, its paraffinic residues (methyl and iaopropyl radicals) form a rather important percentage of the total weight. A valuable help in the examination, especially of the higherboiling fractions, has been the cathode light vacuum distillation with internal condensation, according to the improved methods of Delft chemical engineering laboratory. Another valuable help is the analytical catalytic hydrogenation of aromatic rings which might eventually be present.The dispersion na d no among others enables us to judge if the hydrogenated product is indeed free from aromatic rings. By following the methods of analysis described, the ring formation in cracking was measured quantitatively for the first time, and the inhibitory influence of high-pressure hydrogen on this ring formation was also established quantitatively. A special example proved that by the presence of hydrogen in the berginisation of paraffin wax which caused a hydrogen consumption of 14%, the ring formation was reduced to one-seventh of that in cracking. It is not intended in this paper to give a summary of the actual work which has been carried out, but to call attention to those principles and methods which, in the author's opinion, are still of actual interest for the development of the hydrogenation processes. In the references a survey is found of the papers published up to now by the Delft laboratory (the numbers in parenthesis refer to hydrogenation of fatty oils). THE CHOICE OF THE RAW MATERIAL. It is absolutely necessary to study high-pressure hydrogenation using raw materials which should be as little complicated as possible. The choice will depend on the nature of the process which has to be investigated. It is not desirable to begin with the complicated highpressure hydrogenation of coal, lign
THE HYDROGENATION OF BITUMINOUS GOAL By K. GORDON
. IN a brief discussion of the constitution of coal it is shown that the major constituent of bituminous coal, the uhnin compounds, in which oxygen is the key molecule, largely determines the course of the hydrogenation reactions. Thus the hydrogenation of coal must be essentially different from the hydrogenation of a hydrocarbon such as crude petroleum. The functions of a hydrogenation process to produce a light hydrocarbon oil from bituminous coal are (a) Reduction of the oxygenated groupings of the ulmin, and removal of sulphur and nitrogen before thermal decomposition can set in at these weak points. of the molecules. (b) The resulting high molecular weight product of low hydrogen to carbon ratio must be broken down, and hydrogen added by a combination of cracking and hydrogen saturation to give a mixture of liquid hydrocarbons of low molecular weight and comparatively high hydrogen to carbon ratio. (c)_ A means for the continual purging of ash and unchanged or partially changed solid from the system. The extent to which destructive hydrogenation occurs depends mainly on the reaction temperature, reaction time, catalyst and pressure of hydrogen. The influence of the variation of each of these has been studied in semi-technical plants. By suitable choice of conditions, good yields of light oil have been obtained from all British coals tried, with the exception of anthracites. Typical yields are given. The composition of the ulmin compounds largely determines the suitability of a coal for hydrogenation, and it is therefore now possible to obtain an estimate of the yields, etc., obtainable from a coal by examination of its ultimate analysis. A brief reference is made to the large-scale design which is kept continuously up to date at Billingham, and the auxiliary equip. ment required is discussed. The hydrogenation of the vaporised light oils can be arranged so that any type of petrol from a completely aromatic to a naphthenic-paraffinic spirit is made. Choice of suitable catalysts is necessary for this. The properties are given of petrol, diesel oil and fuel oil made by the hydrogenation of coal.
. Hydrogenation in England has from the beginning been primarily concerned with bituminous coal and the by-products of coal distillation, and as far as can be foretold this will always be the position. While no commercial plant for the hydrogenation of bituminous coal is yet in existence, the advance in knowledge and technique during the last decade has been very great, so that. from a position of relying entirely on imported knowledge, we now in Great Britain are the authorities on the production of hydrocarbon mixtures from bituminous coal, and the design of largescale plant to accomplish this production. COAL. Coal as mined consists of an organic coal substance mixed with ash, but both the coal substance and the ash vary considerably both in quantity and composition. The ash consti
COMPARISON OF CRACKING AND HYDROGENATION AS METHODS OF PRODUCING GASOLINE By R. T. HASLAM,* R. P. RUSSELL t and W. C. ASBURY fi
. THE general applicability of the hydrogenation process to the problems df the petroleum industry has been discussed in previous papers.h 2 This article deals exclusively with the use of the hydrogenation process for production of gasoline from gas oil.1 A critical analysis has been made of the factors which affect the economic position of the hydrogenation process, the ability of the process to compete with cracking and its use in conjunction with cracking. The comparison of hydrogenation and cracking has been made on as broad a basis as possible; the influence of gasoline prices, ranging from the low price now obtaining in the United States to the high price frequently encountered has been studied. The gas oils selected for the comparison include both refractory, low-aniline point, and parafiinic, high-aniline point, stocks met with in normal present-day cracking operations. To-day two general types of hydrogenation are available for the production of gasoline from gas oils; one may be roughly characterised as high-temperature, the other as low-temperature operation. Both types may be carried out in the same apparatus under similar pressure conditions. The former is advantageous where high octane number gasolines are desired, while the latter is especially effective in a range of medium octane number, giving high yields and high conversions. These two phases of gasoline production by hydrogenation are covered in detail in the following sections. TYPES OF HYDROGENATION APAILABLE FOR GASOLINE PRODUCTION. A. High-Temperature Operation. As already outlined in earlier articles,i, 3 the conditions of hydrogenation may be so adjusted that gasolines of high octane number may be produced. Since the temperatures employed in this operation are somewhat higher than generally required in other applications of hydrogenation, this method has been termed "high temperature hydrogenation." In this process, hydrogenation intensity is so limited that nonparaffinic gasoline is produced, but without the formation of tar or coke. The resulting gasolines are low in sulphur, are gum stable and require only minimum amounts of treating. This type operation has been demonstrated in the commercial units of the I.G. Farbenindustrie A.G. on a wide variety of gas oils from coal tars and crude oils and in the pilot plant of the Standard Oil Co. of La. on numerous cracked and virgin gas oils. High-flash high octane number safety fuel and high-solvency paint and lacquer naphthas are among the products made in this operation. Catalysts available for this type of hydrogenation have shown excellent strength, ruggedness and long life. * Standard Oil Development Company, New York City. t Hydro Engineering and Chemical Company, Elizabeth, N.J. $ This process is based on the fundamental work of the I.G. Farbenindustrie A.G. Recent work in this fi
PROPERTIES OF HYDROGENATED MOTOR OILS By R. T. HASLAM,* R. P. RUSSELL t and W. C. ASBURY f
. Tim history of the development of the hydrogenation process, the applications of that process to the problems of oil refining, the type of products producible by hydrogenation and the mode of operation have been discussed in detail in previous papers1, z This paper will be devoted to one phase of the hydrogenation work, namely, hydrogenated lubricating oils, their properties and operating performance, in the automobile engine. The present-day trend in automotive design, toward increase of compression ratio, higher speeds and greater bearing loads, results in severe operating conditions which can be met satisfactorily only by the best of lubricants. Experience gained during the past three years in laboratory and field tests has shown that hydrogenated motor oils, in addition to meeting the exacting requirements of automotive lubrication adequately, have actually demonstrated superior performance to even the best natural lubricants. PROPERTIES DESIRED IN A LUBRICATING OIL. Since the operating viscosity of a lubricant is fixed by engine design, operating conditions and atmospheric temperature, the properties which are desired in a superior lubricating oil are (a) High viscosity index, (b) Low consumption, (c) Minimum tendency to form carbon and sludge, (d) High lubricating value or oiliness, (e) Rapid distribution to bearings. Oils of high viscosity index (good viscosity-temperature relationship) have relatively low viscosity at low temperatures and relatively high viscosity at high temperatures.The former is important in starting engines in cold weather.Since engine cranking speed has been found to be the controlling factor in cold starting, low viscosities at low temperatures are imperative.$Oils of high viscosity at low temperature lower the cranking speed of the engine, retarding or preventing its start. At high temperatures, such as those encountered on engine cylinder walls, the high viscosity index oil does not thin out excessively and lose its " body."High viscosity under hot-engine conditions ensures perfect lubrication and the maintenance of a good piston seal. The effect of viscosity index on the low and high temperature viscosities of oils, all having the same viscosity at 210 F. (60 Saybolt seconds), is clearly shown by the following table TABLE I. Viscosity Index Redwood Seconds At0 F. ... 200 F. ... 400 F. . Kinematic Viscosity at 400 F. (Centistokes) ... ... * Standard Oil Development Company, New York City. t Hydro Engineering and Chemical Company, Elizabeth, N.J. 0. 625,000 584 28-2 152 50. 196,000 58-0 295 164 100. 38,300 575 30,1 1-92 At zero degrees Fahrenheit (with oils of equal viscosity at 210 F.), oils of 100 viscosity index have only onesixteenth the viscosity of oils of zero viscosity index, yet at 400 F. they have 26% higher absolute viscosity than the zero viscosity index oils. For maximum economy in operation it is
HIGH-PRESSURE EXPERIMENTAL PLANT By W. R. ORMANDY, D.Sc., F.I.C._, M.Inst.P.T., and J. BURNS, B.Sc., Ph.D.
. THE authors describe the methods employed and some of the results obtained by Chemical Reactions, Limited, in the development of the process of destructive hydrogenation from laboratory scale up to semi-commercial scale operation. Early investigations were confined to discontinuous experiments in rotating autoclaves, and these investigations demonstrated the necessity of a small continuous laboratory-scale unit which would give results quickly and accurately. The paper describes a laboratory unit capable of dealing with 10-20 ml. of raw material per hour for use as an assay plant for testing raw materials and catalysts under reaction conditions similar to those obtaining in larger scale practice. The accuracy obtainable in this unit- is demonstrated by two experiments. A second unit was designed on somewhat similar lines to the foregoing, but with a throughput of 200 ml. of raw material per hour. This unit is designed to test the efficiencies of different catalysts and catalyst supports during long periods of continuous operation. A series of experiments on this apparatus demonstrates that molybdenum is an efficient catalyst for the conver sion of a high-temperature tar oil to light spirit.The experiments demonstrate, too, the effect of maintaining a fixed percentage of sulphuretted hydrogen in the reaction vessel. It is impossible to deal adequately with many operative problems in destructive hydrogenation in units which are pri. marily intended as assay units, and the next stage of development is portrayed in a plant of 5 litres catalyst capacity, designed for the complete conversion of a raw material to light spirit in one continuous operation. This plant is designed for vapour phase treatment only, but incorporates the basic features of a similar full-scale unit. It is suited for the conversion of creosote to light spirit and results indicate that a yield of spirit amounting to 94% by volume on the raw material may be obtained. The hydrogen used up in the operation amounts to 660 litres per kilo of raw material.The spirit is rich in aromatic compounds and has good anti-knock characteristics. Vapour phase treatment alone is suitable only for tar oils and materials with similar characteristics, and when whole tars of the low-temperature type are treated, it is necessary to submit these to a preliminary treatment in the liquid phase in the presence of supported catalysts. The product from the liquid phase treatment is submitted to a subsequent treatment in the vapour phase.A plant is described for the liquid phase treatment of tar and results indicate that a low-temperature tar can be converted to 71% by volume of middle oil and 23% by volume of light spirit.Subsequent treatment of the middle oil in the vapour phase produces 90% by volume of light spirit, giving a total of 87% by volume of light spirit from the original tar. The t
NEUERE FORTSCHRITTE AUF DEM GEBIETE DER KATALYTISCHEN DRUCKHYDRIERUNG Von Dr. M. PIER
. IN the catalytic high-pressure hydrogenation of oil, tar and coal the lighter oils are treated as vapours in the so-called gas phase method of operation over solid catalyst, which remains permanently fixed in the reaction vessel, while the heavy oils, with which this paper is chiefly concerned, are hydrogenated in the liquid state by the so-called sump phase method of operation. The arrangement characteristic of the gas phase using fixed lump catalyst is only applicable in the sump phase when relatively clean materials, and in particular asphalt-free materials, are to be treated. Low-grade lubricating oils can in this way be converted into high-grade lubricating oils by the addition of hydrogen. It is likewise possible by means of highly active catalysts to refine the most varied materials at temperatures of around 200 C.; it is, for example, possible by the addition of hydrogen to purify in the liquid phase almost without loss crude petrols and crude benzoles which are highly unsaturated and show a strong tendency to form condensation products. Heavy petroleum and cracking residues, tar and coal are, on the other hand, preferably hydrogenated with a finely divided catalyst. The hydrogen is passed through at a rapid rate and recirculated; this maintains intimate contact between the raw material, catalyst and hydrogen. The increasing solubility of hydrogen in oils with temperature is also favourable.It is of advantage if the catalyst and the contents of the reaction vessel have an acid reaction, or at any rate if an alkaline reaction is compensated by the addition of acid. For the conversion of high boiling oils into low boiling products a method of operation was first developed in which the liquid in the oven is recirculated at reaction temperature together with 20% or more of catalyst finely distributed in the oil; only the gas oil and petrol formed together with a little hydrocarbon gas leave the reaction space in the vapour state with the hydrogen. Since it is difficult to separate the catalyst from coal ash and the unconverted coal, though only a small percentage of the latter is left, the liquefaction of coal is carried out for economic reasons with only a small quantity of catalyst, which, however, is sufficient to convert practically the whole of the coal substance into low boiling oils and a small amount of gas. Operation with small quantities of catalyst has been applied with success to the treatment of heavy oil residues and similar oils by hydrogenation at elevated pressure. The catalyst is preferably supported on a' carrier finely distributed in the oil and passes only once through the reaction vessel. In this way it is possible to use a higher temperature than was previously practicable and thereby obtain higher throughputs in the con version of heavy oils to gas oil and petrol.Deterioration of the catalyst caused by the high boiling
AN HISTORICAL ACCOUNT OF HYDROGENATION By Dr. FRIEDRICH BERGIUS TaF, research and technical work on hydrogenation under high pressure were already begun in 1910. In my laboratory at Hanover, I had already constructed the necessary apparatus and equipment to study chemical reactions under pressures up to 300 atmospheres. At that time, Ludwig Landsberg urged me to take up the problem of cracking heavy oils and oil residues into gasoline. Specialists in that field were able to foresee that the progress of the automobile industry would eventually entail a considerable increase in the consumption of gasoline, although nobody had an approximate idea as to the extent of this development. The cracking processes then known were all but perfected. The losses occurring during the cracking operation in the form of coke methane and unsaturated hydrocarbons were very heavy, and the formation of hard petroleum -coke on the walls of the cracking apparatus made it difficult and expensive to carry through the technical process. Having worked upon this problem for some time, I came to the conclusion that the defects of the cracking the cracking oils, that coke was not formed and that the lighter oils so produced were more saturated. The first patent on high-pressure hydrogenation of oils was applied for only in May, 1913, after we were convinced by long experimental work that the reaction could be carried through. This delay in filing the patent caused us extraordinary difficulties later on. The range of temperatures within which hydrogen could be brought to reaction soon proved to be very limited. It depended on working in a range of temperatures within which the velocity of the hydrogenation reaction was not surpassed by the velocity of the cracking reaction, and further on the hydrogen pressure being high enough to guarantee a quick termination of the hydrogenation reaction. At the same time, it was important that a sufficient amount of hydrogen should be always provided for every oil molecule splitting up. This latter condition could, of course, be fulfilled only if oil and hydrogen were thoroughly mixed. It was, therefore, a great progress in the development of the oil hydrogenation reaction when we conducted this experiment in a rotating autoclave (Fig. 2) the equipment of processes and the inferior quality of the unsaturated gasoline so produced could be remedied only by way of replacing the hydrogen, removed in form of methane during the cracking operation, by the addition of new hydrogen in order to prevent the separation of the products, poor in hydrogen, which are apt to cause coking. It was to be expected that the gasoline produced, would in these circumstances be of a rather saturated character. After we had gained some information as to the course of the cracking reaction, we investigated the effect of high-pressure hydrogenation upon petroleum hydrocarbons under temperature conditions causing the cracking reaction to take place. Thus we tried, so to
HYDROGENATION Chairman: DR. F. BERGIUs, HON.M.INST.P.T.General HON.M.INST.P.T. General Reporter: A. E. DUNSTAN, D.Sc., F.I.C., F.C.fi., M.INST.P.T. GENERAL REPORTER'S
This symposium afforded the most comprehensive discussion yet put forward on the subject of Hydrogenation. It was particularly fortunate that the chair was taken by Dr. F. Bergius, whose pioneering work in this direction is too well known to emphasise.Dr. Bergius, in his introductory address, surveys his own work from the year 1910 and discusses the general development of high-pressure work and the first experiments on the hydrogenation of coal that followed preliminary inves. tigations of the origin of this substance from the decom position of cellulose.In the course of these studies it was shown that the younger coals were readily liquefied, but that the anthracites were impossible to hydrogenate. He discusses the fate of the various components of coal substance and proceeds to describe the develop ment of the technical plant installed at Rheinau.The treatment of coal in the presence of catalysts followed on after the conclusion of his own experimental work in 1927, and of course this subsequent work laid the foundations of the hydrogenation process as carried out by the I. G. Dr. M. Pier takes up the story from the standpoint of the work of the I. G. and describes in considerable detail the catalysis of the hydrogenation of coal and of heavy petroleum. Another pioneer in the development of hydrogenation, Dr. W. R. Ormandy, describes, in collaboration with Dr. J. Burns, the experimental units ranging from a small continuous laboratory scale plant capable of dealing with 20 ml.an ml. an hour, and with a larger unit ten times that capacity, leading up to a still larger plant capable of 5 litres catalyst capacity, and which would bring about complete conversion of a raw material to light spirit in one continuous operation. Results in these units are put forward and treatments of lowtemperature and high-temperature tars are'discussed. Two papers are put forward by the technical staff of the Standard Oil Development Co. of New Jersey under the joint authorship,of R. T. Haslam, R. P. Russell and W. C. Asbury. The first of these deals with the pro perties of hydrogenated motor lubricating oils and discusses the viscosity index, consumption, tendency to form sludge, oiliness and distribution of typical hydrogenated material. In brief, the results set forth show that hydrogenated oils give markedly better consumption, no evidence of sludge formation, elimination of difficulties due to sticking piston rings and increased gasoline mileage due to the maintenance of a better piston seal. Incidentally, superior value for viscosity index is obtained. The second paper by the same authors puts forward a comparison of cracking and hydrogenation as methods of producing gasoline.
DISCUSSION. Mr. R. Stansfield referred to the paper on the status of Diesel Fuel Oil Standardisation in the United States, where it was recommended that the engine used should be as sensitive as possible to change of ignition quality and that it should cover the entire range of fuels without difficulty. It was also suggested that the operating conditions should depart as little as possible from service conditions. He emphagised that the schedule of many proposed and tried methods given in Appendix A of this paper implied that simple and inexpensive apparatus is desirable rather than delicate and expensive equipment. The motoring method of test to determine the critical compression ratio seemed best to fit in with requirements as far as the methods dealt with in the analysis made by Dr. Schweitzer were concerned, but it was objected that the method gave an ignition lag which was longer than in a normal engine. Tests made at Delft and also at Sunbury seemed to have established that the fears expressed by several authors regarding possible trouble from this departure from running conditions were groundless, except in extreme cases which could be detected, but which could not in any case be dealt with properly, in a test engine. A critical examination of the many methods of test suggested in the various papers confirmed that the least sensitive engine to change of ignition quality was that which included an air cell more or less separated from the main cylinder, and that direct-injection engines were the most sensitive to change of quality. It was also evident that running tests at full throttle were less sensitive than those with a throttled engine, and any running test less sensitive than the motoring test. Small cylinders, especially those with air cells, had the further disadvantage, readily demonstrated with a Farnboro' indicator, that the successive cycles are not nearly so well reproduced as in the direct-injection type, and this involved integrating methods for obtaining good results.. The tests reported in the paper from the Sunbury laboratory showed that the difference between ratings by a suitable motoring method and by a running method were too small to be of importance for compressionignition engine fuels. If the results of similar tests made in America with an injection of only a very few charges of fuel were examined in terms of behaviour in practical engines, the same conclusion was reached. It was obvious that the motoring test could only be successful if there were control of either the compression ratio or of inlet air and jacket temperature. Without such control the entire range of fuels could not be explored. The C.F.R. motoring method of determining the critical compression ratio (which may be easily adapted to give cetene numbers) and the method described for using the Gardner engine both gave the necessary range, and eliminated the need for any but the simplest instrumentation.' Becker and Stacey's suggestion t
SECONDARY REFERENCE STANDARDS FOR KNOCK-TESTING E. BECKER* and C. B. KASS By Dr. A.
. THE most direct method of determining octane numbers is by comparison of samples with blends of iso-octane and normal heptane, but the cost of the latter prohibits their use in routine testing. As an alternative it is necessary to use secondary standards which incidentally can be made more nearly like normal fuels for spark-ignition engines. However, their use introduces another variable in the test method, particularly if various groups of laboratories use different secondary standards. To reduce this factor to a minimum the Standard Oil Development Company have made available to industry generally their Standard Reference Fuels. These are made from straight-run naphthas to such specifications that they are entirely suitable for use in multi-cylinder engines of aviation, passenger car, bus or truck types. As they are stable products the possibility of change in octane number, gum content or other essential characteristics during storage and use is reduced to a minimum. However, every precaution should be taken to avoid contamination or vapour losses when handling in knock-testing laboratories or while actually making tests. The two Standard Reference Fuels now available have octane number ratings by the " C.F.R. Motor Method " of approximately 44 and 76. For this range the preferred method is to use blends of the two; above 76, C.P. benzene or other suitable antidetonant may be used. Calibration curves, in the preparation of which we have had the generous assistance of the members of the American Detonation Committee, are furnished with the fuels. It should be noted that the curves for blends of these with benzene apply only when using the chemically pure variety. Calibration curves for the various grades of commercial benzole would be somewhat different. Care must also be taken to assure thorough mixing when using benzene blends.Moreover, as the anti-knock quality of benzene blends varies markedly with change of engine temperature conditions, it is advisable to limit the use of secondary standards containing benzene. Such blends are, however, very useful for determining whether or not engine test conditions are correct. Experience has shown the advantages of using the same reference standards in aeroplane- and road-testing as are used in the laboratory. By so doing correlation of results is more easily accomplished. It is therefore desirable that secondary reference fuels have the same degree of anti-knock quality stability with change of engine and temperature testing conditions as the corresponding blends of octane and heptane. This permits blends of two such standards to be used for determining the octane number requirements of engines in service. As an economic matter it will be necessary to continue the use of secondary reference fuels until methods of manufacture are developed that will make available iso-octane and normal heptane at much lower