Symposium on Hydrocarbon Decomposition Presented before the Division of Petroleum Chemistry at the 86th Meeting of the American Chemical Society, Chicago, Ill., September 10 to 15, 1933.
Economics of Petroleum Cracking GUSTAVEGLOFF, Universal Oil Products Company, Chicago, Ill. fields is the equally important HEN c r a c k i n g was The cracking process through crude oil conbusiness of locating new areas put i n t o commercial servation has decreased outlays for drilling pipe to exploit. This calls for the operation about lines, storuge facilities, and refining facilities. expense of a host of geologists, twenty years ago, its motor fuel Through increased yields of gasoline and high p h y s i c i s t s , mathematicians, was looked upon as an inferior antiknock ralues, the automotive indusiry has chemists, and engineers. The product, when as a m a t t e r of rate of depleting oil resources is fact it was s u p e r i o r . An apbeen benefited by cracking. Gas of higher heatlargely governed by the distribuparent shortage of gasoline was ing d u e than natural gas has been available to tion of products available from impending a t that time owing the industries. There has been a consertation each barrel of crude, which prodto the i n c r e a s i n g number of of natural gasoline owing to the lotc-boiling ucts have increased since the admotor cars, and the c r a c k i n g hydrocarbons resulting from the cracking operavent of cracking. At the same process for gasoline was required time, the intensity of search for to meet t h e d e m a n d . Even tion. Coal has been subjected to the highly comnew oil pools is influenced by the t h e m o s t enthusiastic prophet petitice f u d oil. Road oils and asphalts hace rate of depletion. Consequently, did not envision that cracking also been benefited by the cracking industry. the effect of cracking is felt by would b e come the m a n if o 1d Finally, in the realm of synthetic producfs, such the searchers for oil reserves. art it is. as ethylene glycol and ethyl alcohol, the cracking Without cracking, a further The conversion of hydrocarserious p r o b l e m would have bon mixtures under pressure at industry 0Sfer.s a promisina field. d e v e l o p e d in marketing the elevated t e m p e r a t u r es h a s other products, such as kerosene, grown, through an enormous amount of research and commercial application, to be a flex- gas oil, and fuel oil from crude after removal of the gasoline. ible process operating to produce many controlled products. The shifting percentages of products obtained froin a barrel Although it was primarily a means for increasing the quantity of crude petroleum may be visualized from the comparison of gasoline obtainable from crude oil, the cracking process has shown in Table I. enlarged its scope until today its influence is widely felt. Far from being limitled to the gasoline branch of the industry, TABLE I. PRINCIPAL PETROLEUM PRODUCTS FROM CRUDEOIL cracking is an important economic factor touching oil producGASOLINE GAS AND U.S . CREDE AND tion, transportation, refining, the automotive industry, the YE.4R REFINED NAPHTHAKEROSENEFUELOIL L U B R I C A N T S gas and coal industries, the field of alcohol production, and 1000 barrels 7 7 7n 7fi .-" ," ..other industries. 1880 .... 10.3 75.2 .. 2.1 1889 .... 12.8 65.9 7.7 1899 .... 12.9 57.6 14:0 9.1 1904 .. . 10.3 48.3 12.8 11.6 OIL IXDUSTRS 1909 .... 10.7 33.0 33.6 10.7 1914 .... 18.2 24.1 46.5 6.6 Cracking, which is primarily a refining process, has a di1917 21.5 13.1 49.2 5.7 1918 32'6;025 25.3 13.3 53.5 6.2 rect effect upon other branches of the oil industry. By in1919 361,520 25.2 15.4 50.2 5.6 creasing the amounts of desirable commercial products ob1920 433,915 26.1 12.7 48.6 5.7 tainable from a given amount of crude oil, the necessary yearly 1921 443,363 27.1 10.5 51.9 4.7 1922 434,976 28.8 11.0 50.9 4.7 production is strikingly decreased. I n fact, the effect of 1923 538,252 30.0 9.6 49.5 4.5 1924 597,954 31.2 9.3 49.8 . 4.3 cracking upon oil production, based on gasoline alone, has 1925 698,582 32.4 8.1 49 ..3 4.2 been to conserve over 3,000,000,000 barrels in the last six 1926 737,598 34.9 7.9 46.9 4.1 years; that is, without the cracking process, the oil resources of 1927 778,729 36.0 6.S 47.4 3.8 1928 835,711 37.4 6.6 46.7 3.8 the United States would have been depleted by 3,000,000,000 1929 912,191 39.4 5.8 45.4 3.5 1930 866,615 42.0 5.3 40.2 3.7 more barrels of crude in order to meet the motor fuel demand. 1931 894,608 44.3 4.7 37.7 3.0 Had it been necessary to drill a t the rate of 500,000,000 1932 819,997 44.7 5.3 36.9 2.7 barrels more crude oil each year, the added cost to the producer would have been of the order of L100,000,000 a year. I n the refining branch of the industry, the development of It would also have been necessary to provide added pipe lines cracking has opened the doors of other industries to its prodfor transportation and storage tanks for the crude oil. The existing pipe lines for crude oil transportation cover a ucts. The existing investment in cracking equipment distance of about 100,000 miles and represent an investment amounts to over 9400,000,000, and extensive researches going of $800,000,000. This pipe line system has a yearly carrying on in the field of cracking represent a yearly expenditure of capacity of about 1,000,000,000 barrels. TTTithout the crack- over 65,000,000. The products from cracking have had proing process, about 50 per cent increased pipe line capacity found influence upon the course of industries to which they would have been required a t an increased cost of $400,000,000. apply, as well as a greater influence upon the scope of the oil Intimately associated with crude production from known industry.
W
Y
Y
I _
41
42
INDUSTRIAL AND ENGINEERING CHEMISTRY
AUTOMOTIVE INDUSTRY Not only is the oil industry dependent upon the development of motors for its gasoline market, but the automotive industry is essentially dependent upon oil for fuels and lubricants to make its new developments practicable. The total gasoline consumed in the United States has paralleled the increased registration of motor vehicles, as follows: YEAR 1920 1925 1930 1932
AUTOMOBILES In thousandr 9,232 19,937 26,524 24,150
MOTORFUEL CONSUMPTION 1000 barrels 108,945 232 182 398’075 373:770
The trend of the age has been toward ever-increasing rates of speed, and the automotive industry has been supplying increasingly powerful and rapid transportation. As a means towards this end, it has been desirable to increase the compression ratios under which our engines operate. These values have increased since 1924, when about 58 per cent of the cars operated under ratios of less than 4.5 to 1, about 39 per cent a t 4.5-5.0 to 1, and only 3 per cent a t more than 5.0 to 1, until in 1932 over 91 per cent of the cars operated a t compression ratios greater than 5.0 to 1. Each increase in compression pressure of motor operation has required improved quality gasoline. The characteristic which has become more and more desirable is what is known as antiknock value, measured in octane number. This is a property governed by the type of hydrocarbons present in the gasoline, a property which is controllable in cracked gasoline but not in gasoline distilled directly from the crude. Without fuel of suitable composition, motor design along these lines would have remained more or less static. The higher content of aromatic and unsaturated hydrocarbons, and the smaller amount of paraffins in cracked gasoline than in the straight-run product from the same crude oil, as shown in Table 11, indicate the advantage of cracked gasoline in highcompression engines. TABLE11. CHEMICAL ANALYSESOF GASOLINES NAPH-
PARAFFINS
TEENES
Arkansas (Smackover): Straight-run Cracked Califorpia: Straight-run Cracked Kansas: Straight-run Cracked Kentucky (Somerset) : straight-run Cracked Kentucky: Straight-run Cracked Michigan (Mt. P!easant): Straight-run Cracked Oklahoma (Cushing): Straight-run Cracked Pennsylvania: Straight-run Cracked Texas (Van Zandt): Straight-run Cracked 2
%
%
%
%
14.5 21.2
11.3 27.5
7.9 14.7
66.3 36.3
34.9 16.7
2.8 22.0
5.1 23.0
57.2 38.3
20.3 12.8
0.4 17.8
2.7 16.1
76.6 53.3
20.6 11.8
5.3 14.9
3.8 12.5
70.3 60.8
23.1 18.8
2.8 26.0
5.8 12.5
68.3 42.7
7.4 3.1
4.5 33.5
2.9 25.9
85.2 37.5
23.7 18.0
4.9 19.8
1.6 10.9
69.8 61.3
13.0 10.2
6.9 23.5
2.2 9.7
77.9 56.6
0.0 0.0
2.9 35.2
1.7 22.2
95.4 42.6
Table I11 shows the antiknock advantage of cracked compared with straight-run gasolines as determined under comparable conditions. The differences in octane values of straight-run or cracked gasolines may be interpreted in terms of increased power output or efficiency under proper combustion conditions in the motor for each fuel.
Yol. 26, No. 1
TABLE111. OCTANENUMBERS OF STRAIGHT-RUN AND CRACKED GASOLINES (Codperation Fuel Research Steering Committee research method) STRAIQHT-RUN CRACKED GASOLINE GASOLIN~ California (Kettlemen Hills) 60 80 California (Ellwood-Santa FB) 52 74 East Texas 57 70 East Texas (Joiner) 56 73 Texas (Yates) 62 81 Texas (Van Zandt) 43 71 Texas (Refugio) 58 90 Kansas 45 73 Kansas 40 71 Michigan (Mt. Pleasant) 19 64 Midcontinent 51 77 Montana (Kevin Sunburst) 54 81 New Mexico (Hobbs) 55 76 Oklahoma (Allen) 61 78 Oklahoma (Oklahoma City) 47 72 Pennsylvania 50 74 Pennsylvania 43 72 Wyoming (Lost Soldier) 71 81
The efficiency of gasoline is raised by increasing octane numbers to the extent of about 0.3 per cent for each octane number, when running the test motor a t the highest compression ratio with equal knocking. For example, an increase in octane number from 45 to 73 effects an 8 per cent increase in power output or miles per gallon of gasoline. Illustrative of the growing demand for cracked gasolines in modern engines is the changing relation of cracked to straight-run motor fuels. Table I V traces this relation from 1918 through 1932, in percentage of the total gasoline produced from the crude oil. TABLEIV. INCREASED DEMAND FOR CRACKED GASOLINE(8) YEAR 1918 1919 1920 1921 1922 1923 1924 1925
STRAIQHTCRACKED RUN GASOLINE GASOLINBI o/ total yo of total Fasolins gasoltne 10.0 90.0 10.5 89.5 12.9 87.1 16.3 83.7 20.8 79.2 19.4 80.6 18.8 81.2 26.4 73.6
YEAR 1926 1927 1928 1829 1930 1931 1932
STRAIQETCRACKED RUN GABOLINNGASOLINE % of total % o/ total gasoline pasolane 31.2 68.8 30.6 69.4 32.5 67.5 33.0 67.0 38.0 62.0 40.3 59.7 42.8 57.2
As the automotive industry continues to design engines capable of higher speeds and greater power, a continued increase in the ratio of cracked gasoline to straight-run of low antiknock value is indicated. Not only do these trends in automotive design require improved fuels, but the higher speeds of operation demand special lubricants. Here again the products of cracking are a source for at least part of the needed lubricating oils. The unsaturated hydrocarbons resulting from the cracking process can be polymerized to yield synthetic oils suitable for the high gear pressures and great speeds of modern automotive and airplane transportation. Although these synthetic lubricants are produced commercially in relatively small amounts at present, the 1,823,000 barrels of daily cracking capacity in the United States could supply large amounts of raw material for such synthetic lubricants when necessary.
MANUFACTURBD GASINDUSTRY The gas industry, too, has been invaded by products from the cracking process, because of the 250,000,000,000 cubic feet of gases of high heating value which it yields annually. Cracked gases as they are produced have an average heat content of about 1400 B. t. u. per cubic foot, as compared with about 1100 for natural gas and 540 for manufactured gss. The gases from the cracking process have proved useful as fuel in themselves and are excellent blending agents for gases of low heating value. The utilization of cracked gases by gas companies has been demonstrated to be “commercially feasible and economical,” both when the gases are used for “cold enrichment” and “re-
January, 1934
INDUSTRIAL AND
43
ENGINEERING CHEMISTRY
I3ATTERY O F CRACKING U N I T S
formed” or cracked. In the latter case, very high-temperature cracking is resorted to in treating the gases to make them more suitable as domestic or industrial fuel. The reforming of cracked gases is either a process of gas cracking or may include their passage through an incandescent coke bed in the presence of steam, producing water gas at the same time. The object of treatment is the conversion of gases of high heat value into larger volumes of gas of lower heat content. Hydrogen, a product of gas reforming, is being produced in increasing quantities. As one of the products of cracking, hydrogen extends the effects of the cracking process to touch modern synthetic industries. Outstanding among these, as a logical market for the bjdrogen obtained in reforming cracked gases, are the synth&c ammonia and hydrogenation industries. A large proportion of the gas from the cracking process is composed of propane and butane. Since these hydrocarbons are readily liquefied and therefore transported in cylinders, tank cars, and pipe lines under pressure, a rapidly widening field of application for them has been developed. Liquefied gases are being used successfully for heating and lighting in homes located beyond the reach of gas mains and electric lines, and industrially where closely controlled temperatures are especially important. In small towns it has been found satisfactory to pipe these gases, in admixture only with air, to the consumer rather than to maintain a town gas plant, and in some cases this has actually supplanted gas-making plants. In the water gas industry, liquefied petroleum gases have proved to be excellent enriching agents. Propane’s heating value of 2550 B. t. u. per cubic foot and butane’s a t 3200, added to their ease of handling, are clearly illustrative of the value of these gases for enriching others of low heat content. It has been estimated that the cracking units in operation in the United States are a potential source of 900,000,000 gallons of liquid propane and even a greater amount of butane per year. These would be equivalent in heating value to about 70 per cent of the present manufactured gas output. The remarkable growth of the liquefied petroleum gas industry has increased the yearly consumption of liquefied propane and butane from about 1,000,000 gallons in 1927 to over 33,500,000 in 1932. The distribution of these liquefied gases for various uses in 1932 is shown in Table V. The amounts of cracked gases obtainable as sources for
propane and butane are more than ample to meet this growing demand in the gas industry. PRODUCTION OF LIQUEFIED PETROLEUM TABLEV. MARKETED GASES (5) (In thousands of gallona)
-ESTIMATH~D DIBTRIBUTIONIndustrial and Gas manuPRODCCTION Bottled gas miscellaneous facturing 223 192.1 277 ... .___ .. ... 376 1924 II 0 404 1925 465 1926 ... 1927 1,091 1500 400 2,600 4,523 1928 1500 2500 5,900 9,931 1929 2200 4000 18,017 11,800 1930 6184 7023 28,503 15,296 1931 9691 8167 33,630 15,771 1932 a Sale of liquefied petroleum gas confined primarily to bottled gas businesa prior to 1928. YEAR 1922
...
.. ..
...
..
....
The natural gasoline industry, which is another source of these same constituents for liquefied gases, has long felt the sharp competition of cracking. Cracked gasoline, because of the ability to control its properties, does not require the blending with volatile natural gasoline which is so valuable for the straight distilled product. Yet, the very cracking process that yields such finished gasoline, produces a t the same time large amounts of the natural gasoline hydrocarbons, propane, butane, and pentane. The rapid decline of natural gasoline as contrasted with cracked gasoline, in their relations to the total production, is illustrated by the fact that natural gasoline comprised 11.9 per cent in 1929 and dropped sharply to 6.3 per cent in 1932, while cracked gasoline increased from 32.5 to 43.1 per cent in the same period.
C o h INDUSTRY ~ Coal for many years was king of fuel until the growth of the keen competition of fuel oil. In the period 1913 to 1926 coal advanced in tonnage from 478,000,000 to a maximum of 573,000,000, an increase of about 20 per cent. During this same period, fuel oil increased from 114,000,000 barrels to 365,000,000, an increase of more than 200 per cent. The year 1926 was the turning point in coal consumption, whereas fuel oil continued to rise until the peak year of 1929 when 449,000,000barrels were produced, marking an advance of over 300 per cent since 1913. Coal production in 1932 was lower by 35 per cent than in 1913, while the volume of fuel oil was over 150 per cent higher than that year.
INDUSTRIAL AND ENGINEERING CHEMISTRY
44
The comparative data of coal and fuel oil production are as follows: YEAR 1913 1923 1926 1927 1928
FUELOIL BITCMINOUS AND COAL( 4 ) GAS OIL (1) 1000 tons 1000 barrels 478,435 114,310 564,564 287,481 573,367 365,195 517,763 393,066 500,744 427,237
YEAR 1929 1930 1931 1932
FUELOIL BITUMINOGS A N D COAL( 4 ) GAS OIL ( 1 ) 1000 tons 1000 barrels 534,989 448,949 467,526 372,498 382,089 336,967 305,667 294,287
While fuel oil has been competing with coal as fuel, the amount of cracked residue included in the yearly supply of fuel oil has been increasing. The cracking process controls the properties of cracked fuel oil as well as those of cracked gasoline and may be regulated to yield a product to meet any specification. That the demand for special fuel, such as furnace or tractor oils, may at times be more profitably filled than that for gasoline is borne out by the fact that, a t times, some cracking units in the United States are operated to produce furnace oil rather than gasoline. The tabulation of national distribution of gas oil and fuel oil for 1926-30, given in Table J71,is an excellent indication of the fields of domestic and industrial utilization of fuel in which oil fuels are vying successfully with coal. TABLEVI. NATIONAL DISTRIBUTION OF GAS OIL OIL, 1926-30 (3) (In 1000 barrels 1926 Railroads 72,217 S t e a m 8 h i p B (including tankers) 79,287 Gas and. electric power nlantn 33,651 8,951 Smelters and mines 16,102 Iron and steel products Chemicals and allied industries 1;603 Automotive industries Textiles and their products ... Paper and wood pulp 3,183 Logging and lumbering 5,586 Cement and lime plants 3,216 Ceramic industries Food industries 7,674 23,017 Other manufacturing 13,874 Commercial heating 2,905 Domestic heating U. S. Navy, Army trans6,541 ports, etc. 48,701 Fuel by oil companies 7,514 Miscellaneous 6,000 Furnace oils (domestic) USES
...
AKD
FUEL
of 42 gallons each) 1927 1928 1929 1930 1931 69,847 70,680 76,847 67,900 58,150 88,215 89,942 92,870 94,130 83.558 3 0 0 2 1 3 0 9 0 1 31,511 26,748 24,490 6:831 6:897 7,049 5,936 3,626 18,335 19,429 20,208 15,210 12,855 2 0 8 0 3 4 0 0 ' 4,191 3,258 2,907 1:686 3:628 3,224 2,225 1,783 4,852 4,586 4,721 4,472 5,683 3,131 2,792 2,992 2,222 1,833 2 370 2 673 2,578 2,369 1,667 5:051 5:223 3,351 3,007 2,434 3,270 2,995 2,376 1,989 1,598 7 151 6 4 8 8 6,924 7,031 5,660 11:130 10:023 12,861 11,656 9,998 15,750 16,427 17,819 17,343 15,731 5,233 5,971 7,157 9,822 10,446 6,505 8,368 8,192 8,635 9,203 43,452 50,044 55,558 53,436 51,196 9 3 5 3 12 757 11,560 11,233 10,266 6:475 8:300 12,423 15,537 14,213
Satural fuel oil obtained by atmospheric distillation of crude must depend upon the varying constituents of crude oil for its properties. Cracked residual fuels, however, surpass the usual natural fuel oil in heat content, viscosity, and cold test-three important fuel characteristics. The number of British thermal units per gallon of cracked fuel oil is about 10 per cent higher than that of the natural product, measured on a volume basis. Over 400,000,000 barrels of charging stock were treated by the cracking process in 1932. The economic soundness of cracking is apparent from the fact that a crude-yielding straight-run gasoline of low octane number and fuel oil of average properties can be converted into two or three times the amount of high-antiknock cracked gasoline and a fuel residue of superior characteristics, Moreover, the greater heat content of cracked fuel oil mould increase the amount of coal displaced by a given amount of natural fuel oil when measured on a B. t. u. basis. The effect of fuel oil competition upon the coal industry, then, increases with the increasing use of cracking and the corresponding increases in the ratio of cracked to natural fuel oils. I n 1932, 160,000,000 barrels of the total 294,000,000 barrels of fuel oil were cracked fuel. Measured on the basis of B. t. u. content, this volume of cracked fuel is equivalent to about 42,000,000 tons of bituminous coal, or about 14 per cent of the total production of coal in that year.
Vol. 26, No. 1
The effect of cracking upon the fuel field once dominated by coal is not limited, however, to fuel oil. The great volume of gases obtained from cracking, as previously discussed, makes other appreciable inroads into fuel uses, affecting the coal as well as the gas industry. Calculated upon the same B. t. u. basis as above, the 250,000,000 cubic feet of cracked gases produced in 1932 are found to be equivalent to 15,000,000 tons of bituminous coal, or 5 per cent,of the 1932 coal production. A third product from petroleum is in direct competition with coal-petroleum coke; 1,700,000 tons were produced by the cracking process in 1932. This amount of cracked petroleum coke, on a B. t. u. basis, would replace 2,200,000 tons of bituminous coal as fuel-i. e., about 0.7 per cent of the amount of coal produced in 1932. The chief method a t present of producing petroleum coke by the cracking process is a continuous operation, much less expensive than the old batch process and doubly efficient in that it yields a high-quality gasoline at the same time. Some proximate analyses and heat contents of atmospheric distilled and cracking process cokes are given as follows for comparison: COKE Cracked: Midcontinent Texas Smackover (-4rk.) Kentucky Pennsylvania California Atmospheric distilled: 1 2
VOLATILEFREE
HEAT
HzO MATTERCARBON ASH SULFUR VALUE % % % % % B. t. u./lb. 0.50 0.15 0.11 0.39 0.20 0.47 0.6 0.3
8.07 15.02 12.28 11.65 11.39 18.03
91.81 83.21 87.15 87.42 87.42 80.49
0.05 1.62 0.46 0.54 0.99 0.91
0.83 1.96 4.18 0.66 0.22 1.09
15,645 15,456 15,898 16,403 16,248 15.295
2.1 3.9
95.8 94.1
1.5 1.0
0.5 0.7
14,480 14,900
A summary of the inroads made by cracked products into the field of the coal industry is as follows: EQCIVALENT EQWVALEXT CRACKED PRODCCT Fuel oil Oases Petroleum coke a
TO
PRODUCTION I N 1932 In thousands 160,000 barrels 250,000,000 cu. ft. 1,700 tons I
BITITXINOITS COAL" 1000 tone 42,000 15,000 2,200
Total replacement of coal by cracked products B. t. u. basis.
TO
1932 COAL
% 14 5 0.7
__ ~19.7
MISCELLANEOUS INDUSTRIES Road oils, the production of which amounted to 5,425,000 barrels in 1930, 5,177,000 in 1931, and 6,879,000 in 1932, are partly produced by the cracking process. Moreover, cracked road oil may be obtained from crude oils, such as Pennsylvania, which yield no oils as such by atmospheric distillation. For exarriple, cracked road oils can be produced to meet commercial specifications by cracking Pennsylvania paraffinbase crude. Another road-building industry to which cracking is. offering new supplies of a satisfactory product is asphalt making. The amount of asphalt produced from United States petroleum was 3,830,457 tons in 1929, 3,223,888 in 1930, 2,975,690 in 1931, and 2,474,919 in 1932. The production of asphalt by cracking makes it possible to treat a crude petroleum, which contains no asphalt, so as to obtain a good yield of highantiknock gasoline and excellent asphalt. A wedge into the resin field has been made by the cracking process. Synthetic products are being made by the action of aluminum chloride upon cracked distillates. The unsaturated hydrocarbons are polymerized into solid resins and are being marketed. Among the industries which are definitely feeling the competitive influence of the growing use of cracking is the alcohol industry. The highly unsaturated character of cracked products-gaseous and liquid-makes them excellent material
January, 1934
INDUSTRIAL AND ENGINEERING
for the synthesis of alcohols of many kinds. The annual volume of cracked gases produced in the United States is estimated to contain over 50,000,000,000 cubic feet of the unsaturated hydrocarbons-ethylene, propylene, butylenes, amylenes, and butadiene. The potential capacity of the oil industry is over 1,000,000,000 gailons a yearbf alcohols from cracked gases* The present Output Of alcohol from cracked gases is over 4,000,000 gallons a year at a price competitive with that of ethyl alcohol produced from grain or molasses. Ethylene glycol is also produced comand is mercially from as an antifreeze agent* Alcohols (such as isopropyl, sec-butyl, and amyl), glycols, ethers. and related compounds are also being produced com-
CHEMISTRY
45
mercially from cracked gases, and are important solvents. Any conceivable demand for alcohols could be supplied by the oil industry through the use of the cracking process. LITERATURE CITED (1) Am. Petroleum Inst., Statistical Bull. 14 (27), 10 (1933). ( 2 ) Bur. Mines, Monthly Petroleum Statement P102 (Dec., 1932); Am. Petroleum Inst., Petroleum Facts and Figures, 1930. (3) Bur. Mines, Natl. Survey of Fuel Distribution, p. 22 (1930): Bur. Mines, Monthly Mineral Statement 154 (Nov. 16, 1932). (4) Bur. Mines, T e e k l y Coal Rept. 722 (May 16, 1931). (5) Oberfell, Proc. Am. Petrdeum Inst., Sect. 111, p , 11 (1932). RECEIYED September 7, 1933
Halogens and Halogen Compounds in Heat Treatment of Hydrocarbons A. R-. 1
H
. 4 AND ~ ~
ALOGENS and halogen
J. hf ASON, University of Birmingham, Birmingham, England
This paper summarizes the literature on the genation and dehydrogenation c o m p o u n d s m a y be eflect of halogens and halogen compounds on the in certain cases, and in effectused in numerous procing v a r i o u s s y n t h e s e s of the heat treatment of hydrocarbons. Effecfs with esses of heat treatment of hyFriedel-Crafts type for the prod r o c a r b o n s . The aimof this chlorine and iodine are emphasized. A review d u c t i o n of h y d r o c a r b o n s , of the literature on cracking oils with aluminum ketones, and acids. In addition, paper is to indicate the main types of processes and point out t h i s r e a g e n t is used in the chloride is gicen at some length. Other materials, the connections in which their such as zinc chloride and boron triJEuoride, are Gattermann and Hoesch uses arise. Processes p u r e 1y syntheses of aldehydes, and in discussed. References to ParaJlow are gitjen. the of hydrogen chloride of synthesis a r e m a i n l y excluded except those which-seem to ethylene. more d i r e c t l y connected with USE OF HALOGENS ALONE the heat treatment of hydrocarbons or are of special interest in the production of synthetic oils. For various reactions the use of halogens has been proThere are many reasons for the importance of halogens and posed-e. g., in the pyrolysis of methane to give acetylene, halogen compounds in petroleum chemistry and technology. in the production of carbon black from hydrocarbons, and in One is the reactivity of the halogens themselves, especially the capacity of a catalyst in certain cracking reactions of chlorine, in the halogenation of saturated and unsaturated gaseous hydrocarbons. hydrocarbons. Some catalytic activity has been shown with In the first example, an interesting process (68) has been the halogens, especially iodine-e. g., in the splitting of lower recently described. In the pyrolysis of methane to give paraffin hydrocarbons, and in certain hydrogenation reactions. Certain metallic and nonmetallic halides are of great value acetylene, the necessary heat for this endothermic reaction in effecting desired changes with hydrocarbons alone (such is largely supplied by a simultaneous and independent exoas in cracking, polymerization of unsaturated hydrocarbons, thermic reaction in situ-namely, the reaction between hydroand polymerization together with condensation) or hydro- gen and chlorine to form hydrogen chloride. The hydrogen carbons together with halogen compounds such as in reac- chloride can act also as a water-soluble diluent (6). Further tions involving condensation, or addition of hydrogen chloride. results allied to the above were obtained by Mason and Of the halides employed it would be difficult to overestimate Wheeler (36) in experiments on the chlorination of methane the actual and potential importance of aluminum chloride, carried out a t temperatures of 1200' to 1400' C., when apwhich has many uses. It is employed in cracking and as a preciable amounts of acetylene and hydrogen, together with refining agent in effechg desulfurization and removal of the small amounts of ethane and ethylene, were evident in the more undesirable unsaturated hydrocarbons; in these con- exit gases. It has been claimed (51) that in a similar process the temnections its large-scale development depends on its cheap manufacture and economical recovery from residues. Alumi- perature of pyrogenation can be lowered by the use of a num chloride can bring about polymerization and condensa- halogen or halogen compound, and a further variation has tion reactions with olefins, which reactions are of consider- been described (3) where carbon black and hydrogen chloride able interest in the production of synthetic oils. The mecha- are produced by the treatment of the products resulting from nism of aluminum chloride reactions with complex sub- the cracking of heavy hydrocarbon oils in the vapor phase stances such as petroleum fractions is not yet fully under- with chlorine in the presence of hydrogen chloride. The function of halogens and halogen compounds as catastood. Researches have been carried out on the action of aluminum chloride on individual hydrocarbons. This has lysts has been referred to in the recent patent literature resulted in the explanation of the occurrence of certain prod- (40) for converting hydrocarbons, which are normally in a ucts in processes of heat treatment with aluminum chloride gaseous form, into unsaturated hydrocarbons of lower molecuand sometimes (e. g., in ethylene polymerization) in a fairly lar weight. Propane and butane are relatively resistant to cracking. complete explanation of the mechanism of the reaction. Aluminum chloride may also be used to bring about hydro- When high cracking temperatures are used Tith these two
