THE EFFECT OF TEhIPERA4TURE ON THE FORAIAT I O i i OF BESZEXE, TOLUEKE, XYLEKE, S X P H T H A L E K E , AKD ANTHRACEXE FRO11 PETROLEVhl AT AT110SP H E R I C PRESS U R E BY GUSTX\’ EGLOFF AND THOMAS J. TWOMEY
C p to the present writing numerous investigators’ have shown only in a general manner the effect of temperature at atmospheric pressure on the individual aromatic formation from petroleum. It has been pointed out that low temperature ‘‘ cracking processes produce either gasoline or the low boiling aromatics-benzene, toluene and xylene-mixed with gasoline with the major portion of the original high boiling oil changed but slightly, and no naphthalene or anthracene formation. Moderately high temperatures resulted in a cracked ” oil containing benzene, toluene, and xylene, relatively free from gasoline, but with the amount of benzene predominating. Saphthalene and anthracene occurred but in quantities less than that of benzene and its homologues. High temperatures, according to experimental evidence, gave relatively large yields of naphthalene and anthracene with a lesser production of the lighter aromatic compounds. These facts, covering a period of the last sixty or seventy years, are to be found generally in the literature. Due to the European war, which has increased tremendously the demand for benzene and toluene for the manufacture of explosives, attention has been concentrated on the production of these compounds either directly from the cracking of petroleum or indirectly as by-products in the making of gas from petroleum, and coke and gas from coal. Thus it is extremely- important t h a t knowledge of the effect of the various factors on the individual aromatic formation be found. n’ith definite data of this kind it would be possible to obtain a max”
‘ I
References in Historical Review.
imum yield of the desired aromatic from a given amount of oil. n‘ith one or two exceptions aromatic compounds have been made by the cracking of petroleum a t atmospheric pressure either in experimental research or as by-products in the manufacture of gas. Under this condition the factors which influence the formation are ( I ) temperature, ( 2 ) rate of feed, ( 3 ) nature of the oil, and (4) the size of the cracking area. Of these factors temperature has the largest effect on the individual aromatic formation. Heiice, the object of this paper w a s to jitid the ejfect o j tewperatiire 012 the formation of benzene, toluene, xyletie, tiaphtlzaleue, and anthraceue from petroleum with all other factors held constant. It is hoped t h a t the data obtained in this research will furnish further evidence for the theory of cracking, and t h a t it will encourage the manufacturers of gas from petroleum t o develop the by-product production of their tars and liquid hydrocarbons to a maximum.
Historical I n this historical sketch a review of the research on the production of aromatics from the cracking of petroleum and other mineral oils will be given. The object in mind is t o show that this formation as influenced by the various factors has been indicated but slightly bj- any one investigator. From an analysis of the data which has come t o our notice certain regularities in the relationship between the individual aromatics in the cracked oil, depending on the conditions of production, will be brought forth. The Philosophical Transactions of the Royal Society of London for 182j , page 440, contains a paper ‘‘ On S e w Compounds of Carbon and Hydrogen and On Certain Other Products Obtained during the Decomposition of Oil by H e a t ” by Michael Faraday, which will ever be memorable due t o the fact that one of the new compounds described was benzene. I n 1 8 2 j the Portable Gas Company of London prepared gas by decomposing a mixture of fish and vegetable oils. Fara-
day states that in the operation of the company when the oil gas was compressed, a fluid deposited which could be drawn off and presers-ed in the liquid state. Searly one gallon of oil was obtained from 1,000cu. it. of gas compressed. The pressure used was 30 atmospheres. By fractional distillation of this fluid and bq- freezing the portion boiling between 185' and 190' F (85' and 88' C) a compound was separated which he called "Bi-Carburet of Hydrogen." It had a specific gral-ity of 0.85 a t 60" F i I j j c C),freezing point a t 32' F (0' C ) , and in fact the main properties by which benzene is identified a t the present day. The recovered fluid from the gas, specific gravitq- o S Z I , was attacked by sulphuric acid with the evolution of much heat forming a black acid sludge as the lower layer, in a two-layer system which resulted. This action with sulphuric acid is very characteristic of a cracked oil. The work of Faraday's besides resulting in the discovery of benzene is also very important in the history of oil cracking because it demonstrated for the first time that aromatic compounds may be obtained by the cracking of a fish or vegetable oil. No further work was conducted until 1864, when papers by H. Tuttschewl and Voh13 appeared, giving the results of passing oil vapors through red-hot tubes. The production of a permanent gas was noted but no attempt was made to analyze the recovered tar. The first publication of importance was that of L e t n ~ . ~ H e passed Baku petroleum residue, specific gravity 0.870 and boiling above 2 7 0 ' C, through an iron tube seven feet in length and one foot in diameter, and recovered a tar having a specific gravity of I .OIj t o I 2 0 0 . The analysis of the tar is given in Table I . Besides the tar a liquid was also obtained, specific gravity 0.904, which began to boil a t 70' C and consisted of benJour. prakt. Chem., 93, 394 (1864). Dingl. poly. Jour., 177, j 8 (186j). Ibid., 229, 353 (1878).
124
Gzlstac Eglojj avld Thomas J . Twomey
zene, toluene, xylene, cumene, and naphthalene. free from any higher boiling compounds.
TABLE I ~~
Below zooo C
c\ c,
2ooo-z~oo 27Oo-34O0
I
-____.______ ~
~
~
It was
_ _ _ ~- _ _ _ ~
2 . 3 percent water 4 . 6 percent benzene
5.z percent toluene naphthalene and unchanged petroleum
The portion distilling above 340' C was collected in three fractions. 9 . 3 percent petroleum (a) 12 , o percent 2 . 7 percent crude phenanthrene 0 . 7 6 percent pure phenanthrene 5 . z percent petroleum ( b ) 7 . 5 percent z . 4 percent crude phenanthrene 0 . 8 percent pure phenanthrene 6 . 0 4 percent petroleum (c) 8 . o percent I .94 percent crude phenanthrene Two experiments were quoted with tubes four feet in length, one being two and the other one inch in diameter, Using the former, IOO grams of petroleum gave 23.9 grams of tar, specific gravity 0.880, and 3 0 . I liters of gas; whereas with the latter, IOO grams of petroleum yielded 4 6 . 4 grams of tar, specific gravity 0.890, and 54 liters of gas. When the tube was packed with platinized carbon, IOO grams of petroleum gave 66.o grams of tar, specific gravity 0.890, and 7 j , 2 liters of gas. The analysis of these tars showed the presence of benzene, toluene and xylene, but no naphthalene or anthracene. One distillation record in which no gravities were given indicates, however, t h a t slightly more toluene than benzene was formed in the recovered tar. Letny's results cannot be compared directly because there is no statement that the rate of flow of the oil into the tube was constant in each case, and that the same temperature was employed. Moreover, different size retorts were used. On the assumption that the specific gravities represent the combined effects of temperature, rate of feed, and size of retort and that these gravities could have been ob-
Efiect o j Temperature
011
Formation of Beme,te, Etc.
125
tained by temperature effect alone-an assumption we know to be true from our own work-it is possible to point out some interesting facts from his data. High gravity of the tar, meaning a high temperature employed, gave naphthalene and phenanthrene, while low gravity corresponding to low temperature used did not result in the formation of these compounds. And with low temperatures there was greater toluene than benzene formation. That same year Atterburg’ passed Swedish wood tar through an iron tube filled with coke heated to a dull redness in one case and to a bright redness in another. “ A t a bright red heat a tar was obtained which contained all of the products to be found in coal tar. The tar was rich in naphthalene and contained much anthracene. The recovery was about 2 j . o percent. At a dull red heat, 50-60 percent recovery was obtained consisting of a light oil which began to boil a t 5 8 . 0 ” C. It contained 10.0percent toluene with trace of benzene, no naphthalene and 0 . 3 percent anthracene.” In a general way these results are quite similar to those obtained by Letny. They show in two distinct instances the effect of temperature on benzene, toluene, naphthalene and anthracene formation. Two other papers-by Salzmann and Wickelhaus2 and by Lieberman and Burg3-the former on the preparation of benzene from lignite tar oil which corresponds to shale oil, and the latter on the decomposition of lignite tar oil a t white heat, appeared a t this time. The tars were passed through heated iron tubes, and cracked tars were obtained containing aromatic compounds. As the distillation cuts were taken between very wide temperature limits, they cannot be made to show the relationship existing between the individual aromatics In 1884, in England, attention was turned toward the analysis of tar and “hydrocarbon” oil produced as a byBer. deutsch. chern. Ges., 11,
* Ibid., 11, 1431 (1878). Ibid., 11, 723 (1878).
1222
(1878).
product in the manufacture of Pintsch gas, an industry which had been in vogue only a few years. Pintsch gas is made by decomposing petroleum or shale oil with heat, contains a high percentage of illuminants, and is used extensively in the lighting of railroad coaches. Armstrong’ found that the “hydrocarbon” oil-the liquid deposited in a chamber immediately attached t o the pumps and also in the gas containers-and the tar contained benzene, toluene, xylene, trimethyl benzene, pseudocumene, mesitylene and naphthalene. Benzene was present in the largest quantities. Only traces of paraffins, traces of pseudoolefins, large amounts of amylene, hexylene, heptylene, crotonylene and similar compounds of the last type were found to be present. Among one of Armstrong’s conclusions was that high temperatures are necessary for the formation of benzene and anthracene. In the making of Pintsch gas the temperature has a big effect upon the composition of the “hydrocarbon” oil and tar produced. This is brought out by ~~‘illiams2 who analyzed several samples of the hydrocarbon oil. The results follow in Table 2 :
TABLE 2 -
~________~___
~~
No. sample ~-~
- ~.
~ ~~
~
~
~~
~
_
Specific gravity _
A B C D
0.850 0.835 0.840 0.830 0.840
F G
0,800
E
o 760
Percent benzene and toluene -
-
65.6 54.2 j2 .O
45 . 2 44.4 37.8 24.6
While TVilliams did not give the temperatures under which the oils were obtained, we know t h a t the gravity of the samples represents the relative heats t o which the oils were subjected. The analysis brings out that the amounts of benzene and toluene increase with temperature. Very interand bIiller: Jour. Chem. SOC., 49, 74 (1886). Chem. Kewvs, 49, 197 (1884).
1 Armstrong
esting data indeed would have been obtained if the separate quantities of benzene and toluene had been determined in each sample. Due to economic conditions, the first attempt t o commercialize the production of aromatics from petroleum occurred in Russia. Since oil is obtained in large quantities, it is used in the place of coal for the manufacture of gas, and hence scarcitJ- of coal-tar products result. For this reason Russian chemists have concentrated much attention on the manufacture of benzene and allied products from petroleum. The development in Russia which began about 1885 has continued to the present time. Before mentioning the work of the Russian chemists, the publication of Lewes' will be taken up. Lewes cracked Russian petroleum in an iron retort, I O feet in length and four inch diameter, a t 500°,7o0°, goo0 and 1,000' C, the temperature being judged by the color of the retort. X distillate oil, specific gravity o 864, was used. The results follow in Table 3 :
TABLE 3
-
~
~
Temp. Percent recovered oil Sp. gr. recovered oil Distillation
jooo
59 I o 866
c
IIOO 120'
c
125'
I35 140
22.7
o 908
-
-
-
9 0
-
130;
7000 c
I O 2 0
I 3
ISOO
2
j
9.5 4 0 1.5 3 5
1go0
3 0
3 0
200
2
2
Ij O c
4 0
160'
3.5
IjOC
0 5
'
0
0
~
;;;; c o 926
-
Iooooc 11 8 I
-
1 6
5.0 3 3 3 3 j 0
3 6 5 6 5
3 6 0 6 0
IO 0 I O
2 5 2 0
-
-
.o~g
I
O
Xs would he expected the gravity of the recovered oil increased with temperature. while the percent of recovered Jour. SOC.Cliem. I d . ,
11,
j84 (1S9zj.
Gustav Eglofl and Thomas J . Twomey
128
oil decreased. The maximum decrease in the latter occurred between 500' and 700' C, beyond which point the percent of recovered oil decreased a t a much slower rate with increase in temperature. As an analysis of the cracked oil, the distillation record with no description of the method and with no gravities means practically nothing, except to show that the higher the temperature employed the greater the extent of the cracking reaction. It is mentioned that the distillate up to 200' C did contain a large percentage of aromatics. From this statement and from the distillation record it seems that the lower temperatures give more xylene than toluene and more toluene than benzene. The measurement of temperature by eye is not accurate and to all appearances the temperatures indicated for the experiments were lower than was given. The Russian chemists, although they have published considerable concerning the commercial processes developed have disclosed but little data which can be used t o illustrate the desired points in this paper. The method of Nikiforoff' is the most important. A typical analysis of a cracked oil obtained by that process yielded 1 2 .o percent benzene, 2 o percent naphthalene and 0 . 5 percent anthracene. Using the same method, but on a larger scale, Zelinsky? obtained from cracking a Russian petroleum a cracked oil, of which 14. I percent distilled up to 180' C. This fraction contained 5 8 . 0 percent benzene and 28 o percent toluene. Dzwienwonski3 analyzed a gas tar obtained from a Galician mineral residue and found I 2 percent benzene, o 88 percent benzene and toluene, some xylene, 6 o percent naphthalene, and considerable amounts of anthracene." According to Redwood, ' the Sobel plant a t Baku, Russia, obtained by cracking petroleum, from which the kerosene and lighter constituents had been removed, 30-40 percent tar which contained I j to 17 1
2 3 4
Chem. Ztg., 2 0 , 8 (1896). Ibid., 26, 68 (1902). Saphtha, 3 8 j , 4 O j (1901). Jour. SOC. Chem. Ind., 4, 7 5 (1885).
E J x t o j Temperature 011 Formatiou o j Beizzene, Etc.
129
percent fifty percent benzene. On cracking] this tar, after the benzene had been removed, gave 7 to I O percent benzene, 16 percent naphthalene, and 2 to 3 percent anthracene. In the manufacture of gas from petroleum a t Kasan, Russia, W. Rudnew' states that a tar was obtained containing 10-12 percent benzene and 5 o percent naphthalene. The Russian processes for the production of aromatics from petroleum either directly or indirectly from gas manufacture seem to give uniformly more benzene than toluene, and also naphthalene and anthracene. h-o definite data were found concerning the temperature of the cracking, or the rate of feed. Judging from the percent of tar recovered in a few instances, one would expect more benzene than toluene to be produced. Pamfilow? passed petroleum through a hot tube. H e states generally t h a t low temperatures yield large quantities of tar containing aromatic compounds mixed with large amounts of paraffins and olefins. Under the same conditions high temperatures produced considerable yields of naphthalene, little anthracene] and but little benzene. The paper by Dvorkovitch3 delivered before a group of British gas engineers is valuable in relation to the present communication. Different Russian distillate oils were passed through two horizontal pipes, one above the other and connected together. At the end of one pipe was a condenser in which the cracked oil was collected. The results are given in Table 4. From the distillation records it is difficult to determine the quantitative relationship between the individual aromatics. The cut 79' to 83' C does not contain all of the benzene, neither does the cut 1 0 9 ~ - 1 1 3 ~all the toluene. Although stating t h a t the graTities of the cuts did show the presence of aromatics, he neglected to give them. The data, however, are interesting, because they show in a measure the effect of temperature on the cracking reaction, Dingl. poly. Jour., 239, 7 2 (1881). Ztg., 1069 (1897); Russ. Priv., 13, Jour. SOC.Chem. Ind., 12,5, 403 (1893).
* Chem.
322,
Sept. (1897).
TABLE 4 -
-
Temp. Sp. gr. oil used Percent of rec. oil Cu f t . gas Distillation 60°-j9' C
;
83 109 '130 '35 ' I43
1300' F 0.885 37.5 69.8
1 3 0 0 ~F 0.899 38.0 69.0
7.0
5 .9
I. j
1.2
2 .Oj I .02
10.0
7.0
16.44
2.66 I1
.o
2.33
21.66
2 1 j O
225
1600' F 0,863 32 .o 126 .o
'
2.66
2.56 9.06 3.17 14.95 3.17
I
.88
9.41 2.23
13.69 4.45
The modern era has witnessed the first complete comprehensive study of the cracking of petroleum. Dr. W. F. Rittman, chief of the petroleum section of the Bureau of Mines a t Pittsburg, Pa., published in the XoT-ember issue of the JOURNAL OF IiSDUSTRIAL A S D ENGI~SEERING CHEhlISTRY a paper entitled ' ' Thermal Reactions of Petroleum Hydrocarbons in the Vapor Phase,"l in which are given the data obtained by cracking petroleum from different sources a t different temperatures and under different pressures. In this review we are only interested in his results in so far as they show the individual aromatic formation a t different temperatures and a t atmospheric pressure. These results are tabulated in Table j . The data in this table are the best that ha1.e ever been published from which the indix-idual aromatic formation ma>- be pointed out. TT-hile the quantitative amounts of benzene, toluene, q-lene and naphthalene are not given, the distillation cuts with the gal-ities ma>-he safely used for this purpose The distillations n ere coiiducted using an efficient fractionating column This method resulted in the separation of the aromatic, from each other. -4s is seen from the table, the cracked oil w a i distilled making cuts to 100' C , and tlit-11 cl-en- 50' C u p to 300' C . The gra\-ities of each
_-
- -1
Jour. Ind.
H11g. Chem.,
7, 94j (IgIj).
TABLE j Temperature of " Cracking "-joo" C PennsylOil used vania Oklahoma California Oil recovered (per99 0 91.3 cent) 94.5 Sp. gr. of oil recovered 0.799 0.872 0 939 Distillation PerPerPercent Sp. gr. cent Sp. gr. cent Sp. gr. Temperature -~ 1.0 0 . 7 1 8 2 . 3 0.724 3 . 2 0.727 IOOO 6.7 o 761 2.7 0.766 4 . 5 0.785 Ijoo 200" j.3 0.824 4 2 o 802 2 . 5 o 787 38.0 0 . 8 1 4 1 1 . 8 0.835 8 . 8 0.865 250; .. I1 2 13 2 0.891 300 Temperature of Cracking"-6oo C i
~~
-
~~i ~
I
Oil used Oil recovered (percent) Sp. gr. of oil recovered Distillation Temperature IOOO Ijoo 200O 2jo0
i
i
~
( '
~~
< -
~
~~~i
-
Pennsiylvania
~
i
~
Oklahoma
o 840
46 6
0.966
0 . go6
PerPercent Sp. gr. cent o 759 o 803
10.3
~
~
California
50.8
59.9
8.7 I8.j
~
~
PerSp.gr. cent _
0.769 o 817 o 840
_
_
8.3
Sp. gr. _
~
~
0.767o 831 o 861
Ij.0 14 j 3 6 . j 0.81j 1 0 . 5 8 o 2 3 . j 0.850 11 2 0.872 12 o 0.902 300 O j.7 10.901 1 4 o o 894 1 j . j 0.937 Temperature of Cracking"-i jo" C __ __ PennsylOil used vania Oklahoma California Oil recovered (per16.j 17.5 20.9 cent) Sp. gr. of oil recovered I .OI2 1.039 I .092 PerPerPerDistillation cent Sp.gr. cent Sp. gr. cent Sp. gr. Temperature IOOO 16.8 0 . 8 7 6 1 3 . 7 0.873 1 3 . 4 0 . 8 7 0 IjOO 1 4 . 3 o 878 13.4 0.S76 10 8 0 . 8 7 5 zoo0 8 9 0.922 5 . 1 o 9.17 3 . 6 o 917 250: 20 7 Solid 19. I Solid 17 j Solid 300 8.2 .. 6 . 9 0.994 1 'I
'
~
~
~
Gusta;) Egloj-
132
and Thomas J . Twomey
TABLEj-(Contznued) Temperature of "Cracking"-8j0° ~~
Oil used-
Pennsylvania
~
Oil recovered (percent) Sp. gr. of oil recovered Distillation Temperature rooo I joo ~~~
9.7 I 026
Percent ~~
~
18.0
7 0
2ooo
10.0
2 jo0
Solid
300 O
C
-~ __
~~~~
-
Sp. gr. _
~_
0.87j o.8jg 0.885 -
cut are also given. I t is very safe to assume that the method of distillation gave the majority of the benzene in the cut to 100' C, and the major portions of the toluene and xylenes in the cut 100' t o I jo' C. When the cracking was conducted a t temperatures joo' and 600' C, the recovered oil, irrespective of the source, gave on distillation a less amount up t o 100' C than it did in the cut from 100' to I j o ' C. This is positive indication that the amount of benzene is less than the combined amounts of toluene and xylene At 750' C there is again uniformly a larger percent in the cut to 100' than was found in the fraction from 100' to Ijo' C. At this temperature, which is relatively high, this fact proves that benzene is formed in larger amounts than either toluene or xylene, or than the combined quantities of toluene and xylene. A similar phenomena is found a t 8j0' C in the recovered oil from the Pennsylvania crude petroleum, although it is more pronounced. It should also be noted sharply that the amounts of toluene and xylene a t this temperature are less than were obtained a t 750' C. In other words, the toluene and xylene formation reached a maximum, and a t 8jo' C is beginning to decrease. The solid appearing in the distillation cuts from 200° to 250' C a t a cracking temperature of 750' and 8jo' C is partly naphthalene. As the distillation was not carried above 300' C, there is no means of estimating the anthracene formation. The conclusion may again be drawn, however, that a
Eject o j Temperature on Fornzatioii
OJ
Beizzeiqe, Etc. 133
relatively high temperature, 750' C, or above, is required for the formation of naphthalene. This paper of Dr. Rittman's shows better than any of the previous ones, the effect of temperature on the indi\-idual aromatic formation, and that with the type oils used, the formation is independent of the nature of the oil. Other investigators' have also brought out in a measure the effect of temperature, but a discussion of their m7ork adds nothing t o what already has been said. From the history of the production of aromatic compounds by cracking petroleum a t atmospheric pressure, the following conclusions may be drawn : I . There has been no clear cut attempt t o follow the individual aromatic formation with increase of temperature. 2 . Interpretations of the analysis of cracked oils obtained by distillation and by chemical methods point out the following : ( a ) Low temperatures produce more toluene and xylene than benzene, and no naphthalene or anthracene. ( b ) Moderately high temperatures yield more benzene than toluene and xylene, with appreciable amounts of naphthalene and anthracene. (c) High temperatures result in large quantities of naphthalene and anthracene, and still relati\-el>- smaller quantities of benzene, toluene and xylene. EXPERIMENTAL PROCEDURE
The experimental procedure consisted of passing a weighed amount of oil a t a definite rate of feed through an electrically heated furnace. TT-hen a run was completed the cracked oil Yeith: Das Erdol, Braunschweig, 43j (1892). Adiasiewitsch: Chem. Centralbl., I, 401 (1896). Ogloblin: Chem. Centralbl., 79, 2 , 830 (19041. Rosenfeld: Osterr. Chem. Tech. Ztg., 27, I (1909). Schutzen and Jonine: Comptes rendus, 91,825 (1880). Edeleanu: Intern. Pet. Kongr. Paris, 78 (1900);Osterr. Chem. Tech. Ztg., 8, 20 (1902). Boissieu: Bull. SOC.chim. Paris, ( 3 ) 9, 2 (1893). Neffert: Chem. Centralbl., I, 1 j 9 (1899). Lermontowa: Tech. der Naphtha nach XTeith.Ljubawin: Chem. Centralbl., 11, 118 (1899); Jour. Russ. Phi-s. Chem., 31,3 j S (1899).
was tapped from the condenser and weighed, and the volume in the gasometer noted. Oil Used The oil employed for the cracking experiments was what is commercially termed a distillate or gas oil. It was obtained in refining Pennsylvania crude petroleum and analyzed as follows: Sp. gr. o 817 ___._ __ _____ -_____
~
Temp. ~-
200
-
---
- - ~--
"C.
Percent _ _ _ _ _ _ _ ~ ~ _ _ _ _ _ _
'
200'-2 j0' 25 0 O - 3 0 0 300 '-350'
Residue
2
-~-
Sp. gr. --___
.o
7.3 57.0 28 .o 5.5
0.792 0.818 0.827
I n each experiment 574 grams of oil, filtered through filter paper previous to use, was run through the furnace. Electrically Heated Furnace and Apparatus The furnace and apparatus similar to t h a t employed by TV. F. Rittmanl has been described completely. Experiments
As the object of this paper was to follow the individual aromatic formation with change of temperature, the oil was cracked in the furnace a t temperatures 4j0°, 500°, 5 5 0 ° , 6 0 0 ° , 650", joo', 750', 800' and 875' C . During the procedure the temperature was the only factor which was changed for the respective runs. The same oil was used, and was admitted to the cracking area a t the rate of 246 grams per hour. As a very slight i-ariation in the rate would have affected materially the amount and composition of the end products, great care was exerciscd in keeping this factor constant. For each temperature, three or more runs were made, first with the object of obtaining checking results, and secondly, for the purpose of receil-ing enough oil for accurate anal>-sis. 1
Jour. Tnd. Eng. Chem., 6 , 4 7 2 (1914;.
Analysis of O i l The oil as it came from the condensers, especiallv when the result of high temperature cracking reaction, was found to contain appreciable amounts of carbon. For this reason it was filtered before the specific gravity was determined. If not removed, the suspended carbon in the oil w-ould have made the specific gravity of the oil abnormally high in value. The analysis of the cracked oil for benzene, toluene, and xylene was conducted according t o the method devised by the authors The first step in this method of analvsis is a distillation of 170' C. This fraction was then analyzed for benzene, toluene, and xylene. The residue above 170' C was distilled in a manner usually adopted for coal tar. The following cuts were made: 170' to 230' C ; 230' to 270' C ; and 270' C to tar. n'hen naphthalene and anthracene? were found present, the respective fractions were chilled in an ice-salt mixture, and these solid aromatics separated from the oil in the fraction by pressing and drying with filter paper. The results are expressed as crude naphthalene and anthracene. Specific gravities were taken by means of a TTestphal balance a t I j 0' C. EXPERIMENTAL DATA The experimental results are brought out by means of tables and graphs in the following order: Tahlc 6 aiid Fig. I. Tlic c:jj+cci U.t ? w i p i c z ? i t i c mi tlic jwi ~ e u ~t 1 - ii c L o L c ? c do i l , 011 ilic ?as .ioi u i c z t i o i i , aizd 011 ilrc spec ijii g i a , i t j 01 ilic icLo;e/ctioil 7alde 7 a1.d I. 1g 2 Tli~C ~ tC U T i c ~ i z p ratii i c, 311 ilic i i t o i I.cii:ciic, ioIrii i i c , i j liirc, i apliiliuleiic a i i d c r i l t l i i J c c i r i ZIl tllC i l c l ~ , c ~ l c t orl. i l a 6 1 1 (5 illid l,iL!. 3 71LL. e - t i c i i UT f i I I i p 1 ? L l f l l ? L 1 ) : ) '1,z , f O / l l L 7 1 ? C , l i ' l i i llO~1l!/lcX/l 7 l C U l 1 d OllLlii d i l 1lC 011
ilic
h
1
2
~
i
j
c,il i i \ c L i . r o ?
t i i i i i l*iodliciitiii
Rittnian. Twomey and Eglofi: Met. and Chem. Eng.. 13, 6 8 2 ,1915,. Hol(;e: 1:samination of Hj-drocarhon Oils, 11. z jj.
136
Gustac Eglofl and Thomas J . Tworney
Table 9 aizd Fig.4. The effect of temperature on the distillate to 170' C, on the specific gravity of the distillate to 170' C, and on the percent of benzene, toluene, and xylene in the distillate to 170' C. Table I O . The effect of temperature on the specific gravity of the benzene cut 0' to 95 ' C, on the specific gravity of the toluene cut 95' to 120' C. and on the xylene cut 120' t o I j o ' C.
100
OOG
/.oo 90
g.%
80
BOO 0.80
70
700
0.70
60 600
060
50 500 0.50 40
400 0.40
30 300 0.30
20
200
0.20 /O / 00 0.1 0
0 4.
Efject
01Temperature
01z
Fomatioiz
of
Beiizeve, Etc. 137
Table I I . The effect of the temperature on the residue above 170' C of the recox-ered oil, as shown by distillation and specific gravities. Rate
=
TABLE 6 246 grams per hour; amount of oil used =
jj4
grams.
=Itrnosphericpressure Percent of rec oil
AV. -
98 6 96 1
83
0
85
0 I
6 0 6 0
84.9
28 o 34 0 26 o 28 0
86 4
85, I
61 64
j
62.8
44 40 44 25 27 27
6 3 3
43 I
427 425 439
0
6 23 o 24 9 27 6
536
2j.S
jjS o 606 o 612 o 59.5 0
21
730 705 700
6 20
7
29.0
0.813
.o
0.819 0.820 0.819 0.823
0.820
248.0
0.823 0.82j
0.824
430.0
0.851 0.8j4 0.876
0.860
552.0
0,894 0.899 0.904
0.899
IO1
0.964
0.940 593.0
I j 0
s o
9.4
-
0.967 0.960
~
0,958
0.989 i 0.982 0.990
0 0 0
~
71 j . o
-
6 5 6 0
I3 5
-
0.819
0.813 0.814 0.814
72j 0
19 0 19 6
0 .8 2 0
0 . 812
0
jj8 o
___
0.818
0
26.7
27
22 2 21 I
6.0
j j 2 0
I 2
7
~
0 0
AV.
Sp. gr. ~-
I02 0
113 o 88 o 99 0 246 o 249 0
86
xv
__
-~
97.4
8.5 8 85 0 83 4 85 4
Liters of gas per Kg
-
0,995 0.989 1.060 1.060 1,045 1.060 1.030
0.989
, 1.050
20
/8
/6
/4
/2
/O
8
6
4
2
0,
4 0
500
550
600
650
700
750
TernperzhrQs - D y e QS Ca"h7rdz Fig
Table j-.\nal\
2
51s 01
recovered
011
600
850
TABLE 7 Analysis of Recovered Oil
_ _ - - ~ ~- rature _____~
._
Percent benzene ~-
---
450 500 550 600 650 700 750 800 875
Percent toluene
~ - ~ ~ _ _ ~ _ _ _ - _ _ _ ercent Percent Percent xylene napthalene anthracene ~ _ _ ~
~
0 0
0 0
0 0
0 0 0 0
0 3 0 7 2 3 7 0 8 3 7.9
0
0 8
5.0 3
12
18.1
0 3 1 5 3.2 7
6 4
7I '. 50
9
0 0 0 0
2
58 o 6
21 0 11
0 0 0 0
2
1
0 0 0 0
0 0 0 0
0 0 0 0 0 0
4.0 9.8 11 4
0.0
0 0
1.2
2 5
TABLE8
__
Analysis on Basis of Oil Used _ _ -~
_ _ _ ~ _ ~ _ _ ~
Temp' - ~___
Percent benzene
j 00
5 50 600 650 j00
750 800 875
Percent toluene
--I-
~
450
__
~
Percent xylene
Percent naphthalene ______
-
Percent anthracene 0.0 0.0
0.0 0.0
0.0 0.2
0.0
0.0
0.2
0.0
0.0
0.6 1.4 3.1
0.3 0.6
0.0 0.0
1.4
0.0
3.3 4.7 4.4
2.2
1.9
0.0
0.0 0.0 0.0 0.0
2.0
I
1.3
0.0
1.5
I .2
2
.o
0.3
1.1
0.I
0.06
1.5
0.2
0.5 2.5
.6
I
TABLE g Analysis-~of Distillation Cut to 170' C _ _ ~
. . .
-
Temp.
450 500 S50
600
Percent t o I 70 C
2.6 7.3 14.8 26.2
6j
O j 00
31.9 42. j
750 800 875
39.6 38.4 17.6
~
gr'
0.742 0.745 0.742 0.766 0.806 0.841 0.866 0.8j6
0.884
Percent benzene 0.0 0.0 0.0
3.1
15.6 28.8 45.8 54.5 67.8
Percent toluene
Percent xylene
2.4 4.7
0.0 2.1 2.1
.o
10.0
19.3
16.9 16.0 15,I
0.0
8.6
22
20.0
18.2 5.6
5.7
3.2
Fig. 3
on basis of oil used
Table %-Analysis
TABLEIO Specific Gravity of Benzene, Toluene and Xylene Cuts at I j 0 / I 5 " C -~
-
-
Benzenz c u t
Temp. ___
-
0-95 ~
~
c.
0.711
650 700 750
0
800
875 1
0.711 0 711 0 733
784
,
o 828 0.862 0
875
0.881
These values are questionable.
Xylene cut 120-1 5 0 0 -
~
450 5 00 55 0
600
Toluene c u t 95-120' C .
o 762 0.762 0.762 0.786 0 824
0.77' 0 771 0 771 0.792
0.8jO
0.850 0.8801
0.870 I
c.
- ~ - _ _
0.870 0.870
0
825
0.887' 0
870
E#ect oj Tentperatuse
011
Formatioiz o j Bevuene, Etc. 141
0.c
90 0.8 80
