Carbonization of
COAL-OIL MIXTURES A Review of Recent Developments
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DAVID BROWNLIE 46,Grange Road, Ealing, London W. 5, England
FIGURE 1. MITFORD PROCESS PLANT AT TIproN, STAFFORDSHIRE
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INCE about 1930 great attention has been given in Great Britain to processes for the carbonization of mixtures (generally about 50:50) of pulverized coal and liquid fuel, such as heavier petroleum oil or tar fractions, for which claims of a high yield of light oil are made. In modern times the principle of carbonization of coal-oil mixtures was first developed in the United States about 1918 and was then abandoned. Recently it has been revived in Great Britain partly by fuel technologists from the United States. About fifteen processes are now based upon this principle, and the present contribution will attempt to give a concise review of the developments during the past twenty years, particularly in regards to the Bluemner, Carbonol, Knowles, Mitford, and Stephenson processes which are the most recent. The term "coal-oil" means any mixture of finely divided solid hydrocarbon, such as coal, lignite, oil shale, and torbanite, suspended in any hydrocarbons that are liquid or semi-liquid a t ordinary atmospheric temperatures, such as petroleum fractions and heavy residues, tars, or oils from the carbonization of the solid hydrocarbons as well as their heavy residues, and the heavier fractions of the mixed oils and tars resulting from the particular process.
to coke or burned as fuel. A second method is to carbonize at 752-932' F. (400-500" C.) so that the coal-oil mixture is converted into a solid, with all the liquid portion separated as gases and vapors. In some cases also (when coal is used) the carbonization is completed at very high temperatures, up to 1832-2192' F. (1000-1200" C . ) , to form a hard metallurgical coke. To this atmospheric pressure group belong the Ryan, Hampton-Ryan, Thompson-Beeler, Greenstreet, Mitford, Struban, Meiro, and Knowles processes. In the second group the carbonization is carried out a t pressures above that of the atmosphere, which may be as high as 200-300 pounds per square inch and a t temperatures around 572-662" F. (300-350" C.), leaving a liquid residue, or a t 752-932' F. (400-500" C.) or higher, forming coke. Processes of this type are the Lewis, Cranston, Strevens, Mondello, Bluemner, Carbonol, and Stephenson, although full details are not available concerning the operating pressure of the latter process.
Atmospheric-Pressure Carbonization RYANPROCESS. The Ryan or Ryan Oil Digestion process, originated in 1918 by Henry D. Ryan of Boulder, Colo., consisted in mixing pulverized solid fuel, particularly oil shale or coal, in the usual proportion of about 50:50, with heavy oil; the mixture was then heated to 599-653" F. (315-345" C,), or if necessary up to 698°F. (370" C.). The gases and light oils were driven off, and the residual thick liquid mixture was treated in a centrifuge to separate the finely divided solid from the heavy oil; the latter was returned to the process. Any design of retort could be used, but the preferred setting was a horizontal rotary cylinder of iron gauze, dipping
Types of Carbonization Coal-oil mixture processes can be divided into two main groups. The first involves carbonization under ordinary atmospheric pressure conditions and may be carried out at different temperatures. One general method is to heat only to about 572-662' F. (300-350" C.) to drive off light oils, leaving a thick liquid residue which can either be carbonized 629
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VIEWSOF MITFORD Pmxi FIGURE 2 . INTERIOR
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into a bath of hot oil in a stationary outer casing, externally heated from below. Operation was on mechanically continuous lines, the pulverized oil shale or coal being fed into the cylinder a t one end by a screw, and the residual solid material falling through the meshes of the gauze. The main claims of the Ryan process were that carbonization in hot oil resulted in a much higher yield of light oil than if the coal or oil shale and the heavy oil had been heated separately to the same temperature; the quality of the light oil is also superior. Difference of opinion has, however, always existed with regard to the general claims for increased yield of light oil by using the coal-oil mixture principle, and more independent evidence is required. So far as can be discovered, experimental Ryan plants were operated a t York, Pa., a t the Bush Terminal Building in Brooklyn, and in New York, but the process has long since been abandoned. Then in 1919 the Hampton-Ryan process was developed on the same general principle by W. Huntley Hampton of Portland, Ore., who carbonized the mixture in a screw conveyor retort a t about 300-400" F. (150-205" C.) and then treated the thick liquid residue in a ball or tube mill to form a species of "colloidal" fuel. THOMPSON-BEELER PROCESS.About 1919 Cary W. Thompson and Henry C. Beeler, mining engineers of Denver, Colo., developed a process intended primarily for oil shale. They used a long, externally heated, screw conveyor retort, carbonizing with a progressive rise i n temperature to about 900" F. (482" C.); and a solid residue formed. The gases and vapors passed to a special Beeler air-cooled condenser so that the heavy oils returned continuously to the retort. A large experimental retort, 22 feet long, was operated for some time a t Denver but the process apparently never reached the commercial stage. MEIRO PROCESS.About 1926 Adam Meiro, a Russian chemical engineer resident in Brussels, developed a process for the progressive low-temperature carbonization of coal-oil mixtures in a mechanically continuous, screw conveyor type of setting by means of external heating to a niaximum temperature of 770-840" F. (410450" (3.). The retort consisted of a series of horizontal cast_iron or wrought-iron narrowdiameter cylinders, one above the other, with an inclined cylinder a t the bottom and a vertical heating chamber of firebrick. In the top of the setting was a wide-diameter cylindrical condenser, divided transversely into a series of compartments, the lower portion being externally heated by the waste combustion gases from the retort setting. The upper compartments were air-cooled, but in the lower part the heavy oil, boiling a t 570" F. (300" C,), was condensed and returned continuously to the screw conveyor retort, so that the charge was always mixed with the hot oil coming from the process. Nothing is known about the experimental or commercial work that has been undertaken with this process. STRUBAN PROCESS. A. M. A. Struban of London, in 1928, heated a coal-oil mixture to 572-662" F. (300-350" C.) in any convenient type of retort, although in the patent a horizontal, wide-diameter, mechanically continuous cylindrical unit, with a paddle agitator and externally heated, is mentioned. The residual semi-liquid material is then carbonized in retorts of the ordinary type, although in the patent they are described as horizontal, stationary, externally heated, paddle agitator units, operated in series with the first retort. So far as can be ascertained, no large-scale plant of commercial size has been operated, although the subject has been agitated considerably in the British daily press, especially in connection with the various companies concerned. GREENSTREETPROCESS. This process was developed about 1930 by Charles Jason Greenstreet. In 1922 he had
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INDUSTRIAL AND ENGINEERING CHEMISTRY
worked out in the United States the Coalinoil colloidal fuel process (a suspension of pulverized coal in oil using a Jizateur or stabilizer such as lime-rosin soap) along the same lines as the well-known cclloidal fuel developed in 1919 by the Submarine Defense Association, New York, under the chair-
FIGURE 3. GENERAL ARRANGEMENT OF BLUEMTO BRITISH PROCESS PLANT[ACCORDING PATENT 427558 (1933)] SHOWING THREERETORTS IN $ERIES, SEPARATING TOWER,DEPHLEGMATOR TOWER, CONDENSERS, ETC.
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manship of Liiidon W. Bates. In the Greenstreet process, coal41 mixtures are heated a t 392-752' F. (200-400' C.) in any convenient type of retort, still, or other apparatus, although a rotary cylindrical retort generally seems to have been employed. Extraordinary claims have been made for this process, including a yield of 50 to 85 Imperial gallons of oil per long ton (2240 pounds) of coal, in addition to the added oil; some experimental work has apparently been carried out in England In an old low-temperature carbonization plant a t the Cannock & Leacroft Collieries (Cannock, Staffordshire), originally erected for the Vandergrift, American Hydrocarbon, or Bituminoil process, which was abandoned. In the Vandergrift process an ordinary rotary cylindrical retort, like a small cement kiln, was used for solid coal having an outer bath of molten lead within a jacket. The present position in England with regard to the Greenstreet process is somewhat obscured, but apparently work is being carried out in association with John Swallow, a t the old Fusion process rotary-retort plant a t Mansfield (Derbyshire) which had been lying idle for a considerable period. MITFORDPROCESS.The Mitford or Cannock process has attracted a tremendous amount of attention in the British technical and daily press for several years. This is the invention of E. W. Brocklebank and W. B. Mitford, dating from 1931, on the same general lines as the Greenstreet processcarbonization of 50:50 coal-oil mixtures in rotary cylindrical retorts. In the Mitford process, however, the empty steel plate retort is heated to about 932-1112' F. (500-600" C.); the coal-oil mixture is poured in continuously a t one end, with discharge of solid carbonized fuel a t the other. The gases and vapors given off pass to water-cooled condensers, and the resulting mixed crude oil is fractionated a t 410' F. (210' C.) to drive off the light oils, which are passed to a condenser plant on the usual lines. The residual heavy oil, about 90 per cent of the total yield, is then returned to the process, and a fresh amount of liquid fuel is added from time t o time (generally coal-tar creosote) to maintain the necessary volume for the 50:50 coal-oil mixture. The rotary cylindrical retorts are about 50 feet long and 5 feet in diameter, and the process was originally operated at Cannock, Staffordshire, on the site of the Vandergrift process plant. Although C. J. Greenstreet seems to have been associated with the work, the details are not clear.
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Three companies control, or have controlled, the Mitford process-Cleveland Securities Ltd., M. S. & G. Ltd., and National Coke and Oil Company Ltd., all of London. Mitford, who comes from Canada, was also formerly associated with the Vandergrift process. A report on the Mitford process, dated October 5, 1934, was issued by Cecil H. Lander, formerly director of the Fuel Research Board (British Government), who is stated to be the technical adviser to the process. The main point of this report is the statement that 1 long ton of small coal mixed with about 18 Imperial gallons of creosote, along with sufficient heavy oil from the process to make a 50:50 mixture, gjves 15.3 Imperial gallons of high-grade niotor spirit (gasoline) and 15.5 cwt. (78 per cent) of solid smokeless fuel, along with the heavy oil returned to the process. The statement is also made that no deterioration of the heavy oil results, although it is continually being returned to the retort, heated to dryness, and condensed. The yield of light oil claimed is extraordinarily high, but no information seems to have been published concerning the vital matter of the fractionation tests and general quality of the motor spirit. Presumably the added creosote is cracked, and the resulting light oil is added to that from the carbonization of the coal and the decomposition of the tar, but how this takes place a t atmospheric pressure is a mystery. Also nothing is known concerning the wear and tear on the rotary retorts. The original plant of two retorts a t Cannock was operated experimentally for some time but was dismantled and reerected toward the end of 1935 a t Tipton, Staffordshire, along with two more retorts; the plant was claimed to be capable of carbonizing 200 tons of coal every 24 hours and to produce 2250 gallons of motor spirit, 2000 gallons of Diesel oil, and 120 tons of solid smokeless fuel. Judgment on the Mitford process must be suspended until much more definite and reliable information is provided. KNOWLES PROCESS.A large-scale coal-oil plant is operating this process in England a t the new steel works of Stewarts & Lloyds Ltd., a t C o r b y ( n e a r Kettering, Korthamptonshire), and is of particular interest. The proce s s was d e v e l o p e d by the late Alexander S. Knowles of Chicago a n d is now c o n t r o l l e d b y t h e B r a s s e r t Tidewater Development Company, Inc., a subsidiary of H. A. Brassert & Company of Chicago, associated with Universal Oil Products Company. In the early stages solid coal only was carbonized, but after 1925 the trend was toward the carbonization of petroleum residues; the third and latest variation is the heat treatment of coal-oil m i x t u r e s . T h e basic principle, however, is the same for all three processes-that is, the use of a very wide-sole flue oven with the flat floor heated from below by a series of narrow, parallel combustion chambers or flues. The floor is cont i structed of high-alumina fire clay, FIGURE 4. DESIGN silicon carbide, Carborundum, or OF HEAT TREATs i m i l a r m a t e r i a l in the form of MENT VESSEL OR large tiles, and a very high temRETORT OF BLUEMNER PROCESS, WITH p e r a t u r e is used u p t o 1796Two CONCENTRIC 2000' F. (980-1095' C.). T h i s CYLINDERS;THE principle of the flat-sole flue oven INNERONE Is Rowas invented in the United States TATING AT A CONSIDERABLE SPEED by B e r n a r d Zwillinger in 1919, Y
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FIQUREJ 5 . STANDARD DESIQNAND ARRANGEMENT OF CARBONOL TO BRITISH PATENT 396,054 (1931) 1, INCLUD PROCEJSS [ACCORDING INQ RETORT, CRACKING TROUQHS,CONDENSATION CHAMBERS, PUMPS,AND PARTOF TEE BY-PRODUCT RECOVERY PLANT
associated with N. Von Bauer of Germany, but on the death of Zwillinger some of the patents were assigned to the Tar Petroleum Process Company of Chicago, also associated with Universal Oil Products, and H. A. Brassert & Company. About 1925 the Knowles process, originally intended for solid coal, was developed for the carbonization of petroleum residues; the liquid was poured continuously over the heated floor of the oven until a thick layer of coke was formed which was then heated to a high temperature. Plants of this type are operating in the United States a t Bayonne, N. J., Drumright, Okla. (Tidal Refining Company), Point Breeze, Philadelphia, Pa. (Atlantic Refining Company), and a t Lamont, Ill. A Knowles plant for the carbonization of bituminous coal smalls from mines of the Old Ben Corporation was also started in December, 1933, a t West Frankfort, Ill. Full details concerning the Knowles plant a t Corby have not yet been made public, but the installation consists of four ovens and treats a 50:50 mixture of pulverized noncoking bituminous coal and coal-tar fractions from a battery of thirty-five by-product coke ovens producing 3500 tons of coke a week. So far as can be ascertained, the oven floors are each 30 feet long and 7 feet wide, instead of 10 feet wide a h were those used for petroleum residues; the side walls are about 1.5 feet high, and there is an arched roof 4.5 feet from the carbonizing floor a t the center. The liquid mixture of pulverized coal and oil is fed onto the red-hot floor of the oven until there is a coked layer about 6 inches deep; then the flow of the mixture is stopped
and the coke is finally heated to about 1480" F. (805" C.) or higher. Included also is a preheater which raises the incoming cold coal-oil mixture to 895" F. (480" C.), but no information has yet been published concerning the yields obtained and the general performance of the plant a t Corby.
Carbonization under Pressure LEWISPROCESS. One of the coal-oil mixture processes operating under pressure in Great Britain is the invention of G. P. Lewis, developed in 1918 in an experimental plant a t Uxbridge, near London; the liquid mixture was heated a t 752-930" F. (400-500" C.) a t about 270 pounds per square inch pressure, followed by sudden expansion to a large chamber at ordinary atmospheric pressure. For this purpose long, narrow-diameter, steel tubes were fixed horizontally in a combustion chamber for external heating, with a force pump in the circuit to give the desired internal pressure. No definite information was ever made available concerning the yields of light oil obtained, and the process has been abandoned. Incidentally a number of inventors have claimed, both in the coal-oil mixture field and otherwise, that, if carbonization is carried out under pressure and the gases and vapors are allowed to expand suddenly, the yield of light oil is increased. One of the chief processes of this type in Great Britain, although not based on the coal-oil mixture principle, was the Turner process which has also been abandoned. Turner
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and the residual product, still in the thick liquid condition, carbonized solid coal in vertical, intermittent, cast-iron reis then passed from the retort setting to a horizontal pressuretorts with highly superheated steam a t 1058-1220" F. (570reducing vessel, which is essentially a colloid mill, consisting 660" C.) under such conditions that, by means of mechanically of an upper horizontal steel disk revolving a t a high speed operated valves, the pressure in the retort was allowed to and a lower stationary disk between which the mixture passes rise to about 4-6 pounds per square inch gage, followed by in a thin &n. The claim is that this film is finally discharged sudden release a t the rate of about five to nine times a minute. in the true colloidal state; that is, the carbonized coal particles CRANSTON PROCESS. The patents of William M. Cranston, are in such a finely divided condition that they will never commencing in 1928, specified heating the coal-oil mixture separate by gravity from the oil, similar to the condition of a to about 392" F. (200' C.) under approximately 200 pounds "s~lution'~ of glue in water. This is quite different from the per square inch pressure while the mixed gases and vapors so-called colloidal fuel using jixateurs or stabilizers, such as were passed through a nickel gauze catalyst. The claims lime-rosin soap, in which most of the coal particles are not are for combined carbonization, semi-hydrogenation, and in the colloidal state. cracking, while the thick liquid residue is carbonized in a separate retort a t about 1022" F. (550" C.). Another important claim is that, because of the high speed STREVENS PROCESS. John R. Strevens of London, in 1928, of the inner cylinder, the coal-oil mixture is submitted during heated the coal-oil mixture (including, if necessary, a colloid heat treatment to centrifugal force of such strength that stabilizer such as soap) to about 896" F. (480' C.)and as bubbles of gas do not cling to the coal particles and hamper high as 900 pounds per square inch pressure, followed by the heat treatment, while the coal particles are not separated sudden expansion to atmospheric, to bring about carbonizato any appreciable extent from the oil. It is claimed that tion, cracking, and semi-hydrogenation. No commercial this formation of adherent gas bubbles is a serious practical development of either the Cranston or Strevens processes problem in heating coal-oil mixtures under pressure. has been reported. The size of the retorts depends upon the throughput required, but apparently a standard setting carbonizing 25 MONDELLO PROCESS. Beginning in 1924 Hugo Mondello, tons of coal-oil mixture every 24 hours has six retorts, about of Italy, heated coal-oil mixtures with highly superheated 19 to 20 feet (5.8 to 6.1 meters) high, approximately 28.5 steam up to about 1112" F. (600' C.) under a relatively small inches (750 mm.) outside diameter, and 26.6 inches (700 mm.) pressure of 30 to 45 pounds per square inch (but combined inside diameter, with a concentric heat-treatment space of with extremely slow heating) for about 24 hours; if necessary 0.97 inch (25 mm.). Full details cannot yet be obtained with the pressure was suddenly exhausted to atmosphere or to regard to the yields, but they are stated to be about 20 to vacuum. 25 per cent light oil on the original coal-oil mixture and 65 BLUEMNER PROCESS. Erwin Bluemner, an Austrian fuel per cent colloidal fuel, in addition to gas and some heavy technologist resident in Germany, secured British patents oil. Also it is believed that a commercial plant is to be erected (such as Nos. 427,558 and 436,380) for a process consisting in Great Britain, but information is lacking. in heat treatment, with concentric steel tubes, under relatively high-pressure conC A R B ~ N O L PROCESS. ditions of coal-oil mixtures The Carbonol or Woidich FIQURE 6. REMAINDER OF THE CARBONOL PROCESS PLANT NOT composed of 40 to 50 parts process is the invention of SHOWNIN FIGURE 5 , INCLUDINQ THE SEPARATING TOWER. DEF r a n c i s S. W o i d i c h of oil and 50 to 60 parts pulPHLEQMATOR. ETC. Tulsa, Okla., r e s i d e n t in verized coal. The standFrance, who recently obard retort setting consists 1 of a number of high, vertitained h i s f i r s t B r i t i s h patent (396,054), although cal steel cylinders, operathe had s e c u r e d earlier a ing in s e r i e s , so that the coal-oil m i x t u r e can pass l a r g e n u m b e r of United from one to the other with States patents, relating to the temperature raised on petroleum oil refining and p r o g r e s s i v e lines under cracking. The C a r b o n o l accurately controlled conp r o c e s s consists in an exd i t i o n s f r o m 302°F. tremely complicated setting for h e a t i n g coal-oil mix(150" C.) in the first retort tures a t about 599-707' F. to about 806" F. (430" C.) I I I I in the last of the retorts. (315-375' C.) a n d p r e s The latter c o n s i s t of an s u r e s of a b o u t 280-290 outer stationary steel cylinpounds p e r s q u a r e i n c h der heated externally; inwith claims for combined side is a relatively widecarbonization, f r a c t i o n a diameter r o t a t i n g s t e e l tion, and cracking. cylinder with s p i r a l proIn the standard design jections on the o u t s i d e , the retort i s f o r m e d of operating a t 120 r e v o l u three vertical c o n c e n t r i c tions p e r m i n u t e , while steel tubes or narrow-diamethe coal-oil mixture passes ter cylinders, and the coalt h r o u g h the narrow conoil m i x t u r e is caused to centric space between the travel by a force pump up two cylinders, using a force the narrow space between p u m p . The pressure dethe outer and the middle v e l o p e d i s about 280 to tube and t h e n d o w n the 290 pounds per square inch. cor r e s p o n d i n g space beAs usual, the gases and tween the middle and the lighter oils are driven off, inner tube. This arrangeC .
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ment is fixed in a steel plate heating chamber with a firebrick oil-6red combustion chamber to provide external heating of the retort to the maximum of 707" F.; the residual liquid mixture discharges to an adjoining vertical tower with a separating chamber a t the center. In the upper part the gases and lighter oil vapors separate and pass to a fraction tower with a dephlegmator, where the light oil is separated into Bitumenol 1 (high-grade gasoline), Bitumenol 2 (good-grade gasoline), and Bitumenol 3 (heavy fractions for use in Diesel engines). In the lower part of the separator tower the residual coal-oil mixture passes to a cracking chamber built around the outside of the retort chamber and containing a series of troughs filled with molten lead or other metal kept a t a high temperature by means of the retort combustion chamber. The result is to give further light oil vapors, and the final product, still liquid, is then discharged, being known as Carbonol stated to consist of 50 parts each of solids and liquids. No details are given, however, concerning the proportions of the original coal-oil mixture, and nothing seems to be known as regards the exact yields claimed except that the amount of light oil is very high. According to reports a Carbonol plant is to be erected in Great Britain. As in the Bluemner process it is further claimed that, because of the extreme subdivision due to the use of pulverized coal, carbonization, and solution in the hot oil of the bituminous content, the residual Carbonol, consisting of heavy oil and carbon particles, is in the true colloidal conditions, although no colloid mill is incorporated and there is no reference to troubles with adherent gas bubbles. STEPHENSON PROCESS. This invention of H. P. Stephenson. formerly a chemist with Imperial Chemical Industries Ltd., a t Billingham-on-Tees, is controlled by Coal and Allied Industries Ltd.,of London, formerly Motor Fuel Proprietary Ltd. The latter company owned the Dvorkovitz process of low-temperature carbonization (not, however, for coal-oil mixtures) for which an experimental plant formerly existed a t Slough, near London. In September, 1934, Coal and Allied Industries Ltd., with a capital of 2300,000 ($1,500,000) issued a prospectus referring to a report on the Stephenson process by C. K. Ingold, professor of organic chemistry at London University, and J. W. McBain of Stanford University, Calif. No technical information is given in this prospectus, but the heating of coal-oil mixtures is mentioned. According
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FIGURE7. ONE DESIGNOF SETTING FOR THE STEPHENSON PROCFSS ACCORDIXGTO THE FIRSTBRITISHPATENT[431,163 (I 933) 1, USINGHORIZONTAL CONCENTRIC STEEL TUBES, w I T H C o A L PULVERIZERS, COAL-OILMIXING TANKS, AND CONDENSING FORCE PUMP, IN THE CIRCUIT.THIS, PLANT HOWEVER, DOESNOTSEEMTO HAVEBEENOPERATED.
to the report of Ingold and McBain, 1 long ton of coal gives the extraordinary yield of 27.3 Imperial gallons of light oil, along with 16 cwt. (80 per cent) of low-grade smokeless fuel. The actual report, however, was apparently never made available to the public, and the prospectus merely contains a letter by Ingold. Apparently no technical information of any kind was published concerning the Stephenson process until October, 1935, when the first British patent (431,063) appeared. According to the patent, the process consists in carbonizing coal-oil mixtures, in the presence of a catalyst such as alkaline earths, in an apparatus consisting of alloy steel tubes formed of small vertical preheater coils and long horizontal steel tube units made of one tube inside another. The coal-oil mixture is raised in the preheater coils to about 572-752' F. (300-400" C.), using a force pump in the circuit, and is then carbonized a t 932-1112' F. (500-800" C.) in the narrow concentric space between the horizontal tubes; the pressure is stated to be about 750 pounds per square inch. These tubes have a series of four offtake pipes for the gases and vapors, and carbonization is completed to the solid condition; the carbonized fuel is discharged from the end of the tubes. How this method can operate is not clear; no explanation is given of the formation of solid fuel in the narrow concentric space or of the separation of the gases and light oil vapors from the liquid coal-oil mixture under high pressure. About the end of September, 1935, it was stated that a large plant had been completed and started a t Seaham Harbour, County Durham; a throughput of 500 tons of coal per 24 hours was claimed, in the form of a 2 to 1 mixture-that is, 500 tons of coal and 250 tons of oil. According to some of the sensational statements that have appeared in the British daily press, the plant was to produce 4,000,000 gallons of petrol (gasoline), 400,000 gallons of Diesel oil, and 100,000 tons of carbonized coal a year. This corresponds, on the assumption of 365 days a year, to 21.9 gallons of motor spirit, 2.19 gallons of Diesel oil, and 57.4 per cent of carbonized fuel per ton of coal. Since the plant cannot operate continuously every day, the claim would appear to be 32 to 40 gallons of light oil pert on of coal (since presumably only about 60 t o 70 per cent of the light oil is gasoline) and 32 to 40 gallons Diesel oil. No technical details, however, can be obtained concerning the design and the operating results of this plant at Seaham Harbour, and the
exact method of cnrbouimtiou is not. known; a 11~1i111icr of other Stephenson patents are still pending. The plant started 011 Xovemher 12, 1935, bot was partly destroyed by fire on December 13, and at the time of writing (February, 1936) the repairs have not yet been conipleted. According to statements made at the anuual mn't.ing of Coal arid Allied Industries Ltd. (including reports in t h i s daily press), the process wiiuld mot operate with a 2: 1 coal-oil mixture, and the usual 50:50 proportion had to he uscd. Also it is now stated that present insta1latii.n~ at, the, Seaharn Harbour plant consist of fifty-one ovens, each of which can treat 2.75 tons of coal and 2.75 tiins of hcavy oil every 24 hours (equal to 140 tons of coal and much less thail the original estimate). Apparently also t.he ovens do not operate at a pressure above atmospheric, and apparently shallow metal trays are used for the mixture. According to another statement in a progress report. issued hy Coal and Allied Industries LM., the estimated capacity of the plant of fifty-one ovens is 320 tons of coal-oil niixtnre
R day (50:50), producing &3,000 galloils 0 1 mirie oil which on treatment shorild give tlrp fdloiving yields in Imperial
gxllons:
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n'o infonuatioii is giveri as t u tlrc rjuaut,ity and quality of tlir heavy oil used as make-up that niust Be iricluded in the yields per ton of coal. The sinokeless fuel to tie placed on the market under the name of "Cauda" is estimated at 130 tons a day, and the plant is stated to have cost ahout, 2205,000 ($1,025,000). Further infornmtinri ir au.sit,wl wit,h iiitrreat. Itrcvirb:s \Ieieh 91, 1U:W
Polymerized Acrylic Acid Derivatives
L. KLEIN AND W. T. PEARCE The Resinous Products & Chemical Company. Inc Philadelphia. Pa.
Properties of Interest to the Varnish and Lacquer Industry
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MOSC the more recent industrial de velopments in the field of synthetic resins has been the growing importance of thr, acrylic resins, supplied commercially in this country under the trade name of Acryloid.' This term has been applied generally to the polymerized derivatives of acrylic acid (CH? : CII-COOII) and a-inethyl acrylic acid (CHI : t.COOFI), CB,
hereafter daignated "methacrylic acid." 0 importance are the polymerized lower ester L Hegirteied trade name of the %ohm Br Haas Comp Pruduetr R. Chemical C o m p n n y of Philhdeiphis.
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DEMONRTRATI~N 011 TEE EXTENSIOF POLYMETHYL ACRYLATEF ~ m s
The unstretohed film ie oompared with one to which 8mdi damp ie added in one O B B ~and s 500gram weight in the other.
Below: DEMONSTRATION OF THE WATERWHITE COLORA N D TRANSPARENCY OF A 20 P E R CENT SOLUTION O F A N ACHYLO~D POLYXER
: u d &yl, d tlieae t , w acids and their co-polynlers. Higher aliplintir as wcll as aromatic and I~rancli-chained e s t e r s have I>eenprepartxl, h i t so far these types IIRV(~ had a rnore limited use-
