Apr., 1916
T H E JOCRAVAL O F IiVDlrSI'RI.1L
a n d I : I . ~ O >a n d t h e a m o u n t Qf morphine should never be less t h a n two-thirds of t h e entire alkaloidal content. F o r t h e extract of t h e unroasted opium t h e ratio should v a r y between I : I . jo a n d I : z + , a n d t h e proportion of morphine should naturally be t h e reverse of t h a t for tschandu. Samples of T y p e I11 will show a n abnormal alkaloidal composition similar t o t h a t of tschandu; this, however, m a y be moderated or exaggerated, depending on whether yen shee was added t o t h e ordi-
A N D ENGINEERING CHEMISTRY
351
n a r y extract or t o tschandu. Suspicion will also be directed towards a sample when its ash percentage exceeds 8 . 0 , or its water-insoluble residue (consisting largely of carbon) exceeds 5 . 0 in t h e d r y material. T h e peculiar and characteristic odor of yen shee m a y also furnish a clue if noticed in t h e smoking opium. Samples of T y p e ITr m a y be identified b y t h e usual physical, chemical a n d microscopical tests. U S. CUSTOMS LABORATORY BALTIMORE, MARYLAID
LABORATORY AND PLANT THE MANUFACTURE OF GASOLINE AND BENZENETOLUENE FROM PETROLEUM AND OTHER HYDROCARBONS By W. F. RITTMAN, C. B. DUTTON AND
E. W. D E A N
Received March 6 , 1916
T h e U. S. Bureau of Mines has just published Bulletin 114,bearing t h e above title. I n view of t h e wide-spread interest i n t h e processes described in this publication, t h e authors have, u p o n request, prepared t h e following a b s t r a c t , including supplement a r y information acquired since t h e completion of t h e ] original manuscript.- [EDITOR. T h e bulletin deals with t h e cracking of petroleum a n d other hydrocarbons a n d the productions thereby of gasoline or of benzene a n d toluene. T h e first p a r t is devoted t o a discussion of t h e principles involved. T h e second deals with t h e large-scale development of both processes. T h e l a t t e r section is of primary interest t o readers of THIS J O U R N A L , as t h e matters discussed in t h e forepart of t h e bulletin h a v e been covered generally b y articles previously published.' PURPOSE O F EXPERIMENTS
In connection with t h e description of a n d c o m m e n t on t h e large-scale development of t h e benzene-toluene process which follows, it should b e k e p t in m i n d t h a t t h e object in, view was t o demonstrate t h e commercial feasibility of t h e process. Certain refinements i n mechanical equipment were out of t h e question a t t h e outset since such devices were not suited t o minute s t u d y of each step in t h e process, b u t could be installed at a n y t i m e after t h e commercial possibilities of t h e process h a d been demonstrated; e . g., such obvious improvements as feeding t h e oil b y a single p u m p through a common header, or t h e use of one large condenser for all t h e tubes in place of individual condensers for each t u b e , were set aside in favor of less desirable mechanical arrangements b y which each tube could be kept as a separate unit a n d its products analyzed a p a r t f r o m those of t h e remaining tubes. I t will be recognized readily t h a t it was first necessary t o prove t h a t t h e process would work as well o n a commercial basis as in t h e laboratory. This could be done only a t t h e sacrifice of a very considerable percentage of t h e product formed. Elimination of THIS JOURNAL, 6 (19141, 383, 472; 7 (1915), 945, 1014, 1019; 8 (1916), 20; M e t . and Chem. E m . , 13 (1915). 682.
this loss was regarded as a mere matter of course, t o be t a k e n u p a t will. These losses continued, however, throughout t h e period covered b y t h e d a t a published. L A R G E - S C A L E D E V E L O P M E N T 0 F B E S ZE S E - T0 L C E N E
PROCESS
Under t h e t e r m s of t h e agreement with t h e Aetna Explosives Co., t h e work incident t o t h e development of t h e benzene-toluene process on a scale of commercial magnitude was begun a t Pittsburgh, P a . il plant was acquired a n d t h e experimentation was begun which was t o result in t h e successful working o u t of t h e process on a commercial scale. E X P E R I M E N T S WITH V A R I O U S S I Z E S O F T U B E S
The original apparatus used in the laboratory experiments consisted of a tube 1 1 / ~ in. in diameter by 3 it. in length. When the development work was undertaken, a small number of experiments with a tube of the same internal diameter, but 41/2 ft. in length, sufficed t o show that the longer tube gave the same general results. A second tube z1/2 in. in diameter and 4 ft. long gave equal11 satisfactory results, and was, therefore, promptly abandoned in favor of a tube 4l/2 in. in diameter and 6 f t . long which was found to give results comparable with those obtained with the original small tube. Some half dozen or more runs were made at varying temperatures and rates of feed, a t a pressure of 2 5 0 lbs. per sq. in. A t a temperature of 600' C. and a rate of feed of 8 gal. per hour an oil of 0.94 specific gravity was recovered, which on distillation in the laboratory gave a benzene yield of 1 2 per cent and a toluene yield of 8 per cent, on the basis of recovered oil. Thus sufficiently favorable results were obtained with this apparatus to justify its abandonment in favor of one of still larger size. In the next series of experiments the length of the tube was increased from 6 to I O ft., the diameter remaining the same. It was found that operations at comparable temperatures and pressures with those used in the shorter tubes gave the same relative yields of aromatic hydrocarbons. The increased length, however, which exposed the gases for a longer period of time to the influence of temperature and pressure, made it possible to increase the rate of feed from 8 to I O gal. per hour. This change illustrates one of the important means of controlling the time element in a gaseous hydrocarbon reaction. The results obtained with the single 41/2-in. tube were of such a character as to justify experiments to determine whether or not satisfactory yields could be obtained by encasing I O tubes in a single combustion chamber. Accordingly, a furnace containing a battery of I O tubes, 4l/2 in. in diameter by I O ft. in length, was constructed. Experience with this installation proved that the 41/2-in. tube was of too small diameter t o give efficient results. I t
352
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
was demonstrated by later experiments that to obtain maximum efficiency a tube a t least double or treble this diameter should be used. Tubes of 1 0 " ~ in. internal diameter are now being efficiently employed. E X P E R I M E N T S WITH
6-IK.
x
9-FT. T U B E
With a tube 6 in. in diameter and 9 ft. long it was found that the feed could be increased to 14 gal. per hour, an increase in capacity of 4 gal. per hr. over the 41/2-in. tube. An average of j runs, which were made a t a temperature of Gooo C. and 250 lbs. pressure, and a rate of flov of 1 j gal. per hr., gave 8.3 per cent toluene and 13.5 per cent benzene, on the basis of recovered oil. ilpproximately 40 runs were made a t temperatures ranging from 500' C. to 7 2j ' C. and a t a constant pressure of 250 lbs., but with varying rates' of oil feed. With Oklahoma crude oil the optimum conditions were approximately Gooc C., a feed of 14 gal., and a pressure of 2jo lbs. per sq. in. This tube was abandoned in favor of one of the same diameter, but I ft,, longer, since it had previously been demonstrated in experiments with the smaller tubes that an increase in length
1'01. 8, No. 4
This is confirmed by the data obtained in this series of experiments. It will be seen from Fig. I that the amount of benzene formed increases progressively with increase of temperature up to 750' C., and shows a slight decrease from this point up to 800' C. As the temperature is increased beyond 800' C. the percentage of benzene formed sharply drops until a t 850' C. it is practically negligible. Toluene formation, on the other hand, shows a consistent and steady decrease above a temperature of 6jo" C. This result again is in accord with the evidence obtained from the experiments in the small electricaily heated furnace. It will be noted that the total yields of benzene and toluene shown in Table I are considerably below the total percentage of aromatic hydrocarbonq, formed in the small laboratory apparatus.' This is due to two causes: ( I ) the xylene formed is left out of consideration; ( 2 ) the condensation was wholly inadequate to permit a full recovery of the aromatic hydrocarbons formed. The gases, after passing through the condenser, issued from the end of the pipe in the form of a white cloud, whereas the gases could not have been noted if none but fixed gases
0 FIGS.1
A N D II-SFFECT
TEMPERATURES O N FORMATION O B BENZENE A N D TOLUENE WHEN AN O K L A H O M A CONSTANT PRESSURE AND RATEOF OIL-FEED IN TUBES O F DIFFERENT DIAMETERS
OF V A R Y I N G
permitted more oil to be fed in during a given period of time, owing to the increase in heating surface. EXPERIMENTS WITH 6-IK. X IO-FT. T U B E With the installation of a 6-in. X io-ft. tube a force-feed pump was employed, with the object of obtaining a more constant flow than could be obtained by gravity feed, where the pressure exerted by the column of oil was relied on to overcome the pressure of the gases and force the oil into the tube. It was found possible to obtain a better adjustment of temperature and pressure conditions with relation to the amount of oil supplied. Oklahoma crude oil was used in most of these experiments, the results of which appear in Table I. Little uniformity is shown in the tabulated results unless the data be compared for the same rate of feed at different temperatures and pressures. At a constant temperature and rate of feed, but with varying pressures, the percentage of benzene and toluene formed increased with increase of pressure; e . g., at a temperature of 600' C. and a rate of feed of 1 2 gal. per hr., 4.3 per cent of benzene was formed a t a pressure of I O O lbs.; a t 150 lbs., 4.9 per cent, and a t 2 2 j lbs., 6.7 per cent. Similar variations were obtained when the pressure was increased a t higher temperatures; e . g., at 750' C. and a feed of 14 gal. per hr., 4.4 per cent of benzenetoluene was formed at a pressure of 175 lbs., and 5.2 per cent a t 2 2 j lbs. The higher temperatures, as has been stated,2 are favorable for benzene formation, but prejudicial to toluene formation. 1 A smaller number of runs were made a t temperatures between 600' and 725' C. a n d 125 lbs. pressure, b u t t h e yields were considerably decreased, this result being due as much t o failure t o obtain t h e proper r a t e of oil feed as t o t h e unsuitability of the pressure for converting oil t o aromatic hydrocarbons. The necessity of obtaining concrete results with a minimum loss of time made it necessary t o suspend experiments with varying rates of pressure for t h e time being. 2 K. F. Rittman, THISJOURNAL, 7 (1915), 945
C R U D E OIL IS C R A C K E D AT
escaped: a large proportion of the volatile liquids formed were thus carried away by the gases, the quantity of which could TABLEI-BENZEHE A N D TOLUENE FORMED FROM CRACKIXG OKLAHOMA CRUDEOIL I N A SINGLE-TIUBE FURNACE (TUBE6 I N . IN DIAMETER AND 10 FT. L O X G ) , AT VARYING TEMPERATURES, PRESSURES, A H D RATES OF OIL F E E D ( Q ) Distillation of Oklahoma Crude Oil Used for Cracking NO. 1 7 3 4 5 6 7 75' lobo 125' 1.50' 200' 250' 300' C. T e m p . of C u t , . 11.0 14.0 8.0 15.5 7.0 3.5 Volume % ..... 1 . 5 Sp. GI .... , . . . , 0.720 0.722 0.735 0.752 0.782 0.786 0.836 Pressure Per cent on Basis PER CENTI N Lbs. Gal. OIL RENO. per Oil COVERED OIL RECOVERED . of Original Oil OF T e m p . sq. per P e r Sp. Ben- Tol- TOTAL Ben- Tol- TOTAL RITKS" C . (,b,l in. hr. cent GI. zene uene B. T. zene uene B . A T 1 . 8 2.5 4.3 7.2 10.0 17.2 1 600 100 12 25 . . . . 3.5 2.5 6.0 1 650 100 12 21 . . . 1 6 . 7 1 2 . 0 2 8 . ( 0 . 9 1 . 3 2.2 . . . . . . , . . . 18 700 100 1 3.3 2.0 5.3 5 17 . . . . 1 9 . 4 i i : s 1 700 100 2 . 4 2 . 5 4.9 1 0 . 0 1 9 . 6 . . . 9 . 6 I50 12 25 1 600 3.2 3.2 6 . 4 7 . 6 15.2 7.6 9 42 , . . . 1 650 175 7 . 7 2.3 5.0 1 0 . 5 2 2 . 8 1 2 . 3 22 . . , . 175 18 1 700 2.2 2.2 4.4 1 750 175 14 21 . . . . 1 0 . 5 1 0 . 5 2 1 . 0 4 . 6 2.4 7 . 0 1 650 200 15 22 . . . . 2 1 . 0 1 1 . 0 3 2 . 0 1.6 2.8 4.4 5.2 8.2 3.0 1 675 200 27 54 . . . . 2 . 5 1 . 9 4.1' 9.5 22.0 1 700 200 12 20 . . . . 1 2 . 5 4 . 2 2.5 6 . i 1 600 225 12 18 . . . . 2 3 . 3 13.9 3 7 . 2 4.5 3.0 7 . 5 1 650 225 18 22 . . . . 2 0 . 4 13.7 34.1 2.9 2.7 5.6 1 700 225 18 22 . . . . 13.2 12.3 2 5 . 5 3 . 3 1.9 5.2 9 . 5 26.0 1 750 225 14 20 . , . . 1 6 . 5 1 650 250 ,19 1 7 . . . . 2 1 . 8 1 2 . 4 3 4 . 2 3.z 2.1 5 . 8 3 . i 3.4 7.1 690 250 18 35 . . . . 1 0 . 6 9 . 7 2 0 . 3 4 2.4 4.0 6.4 9 . 1 14.6 5.5 1 650 250 19 44 . . . . 1 675 250 16 22 . . . . 1 0 . 9 1 0 . 9 2 1 . 8 2.4 2.4 4.8 3.4 2 . ) 6.1 . . . . 14.2 11.2 25.4 700 2 5 0 1 7 3 3.4 2.2 5.6 . . . . 2 0 . 0 12.9 32.9 1 750 250 17 2.0 1.2 3.2 3.0 8.0 2 600 150 17 40 0 . 8 9 4 . 0 11.0 2.4 1.4 3.8 I .o 3 650 150 1 7 34 0 . 9 1 2.6 2.0 4.6 6 . 0 1 4 . 0 8.0 5 600 200 17 33 0 . 9 2 3.2 2.9 6.1 9.0 19.0 5 600 250 17 32 0 . 9 3 10.0 4.8 3.5 8.3 30 0 . 9 6 16.0 1 1 . 5 27.5 4 650 250 4.9 2.8 7.7 27 0 . 9 9 1 8 . 0 10.5 28.5 750 250 4 4.8 1 8 6.6 1 0 . 0 3 6 . 0 2 6 . 0 1 . 0 1 800 250 17 18 1 0.9 0.6 1 . 5 4.0 10.0 6.0 850 250 17 15 1 . 0 3 2 (a)Average results low, due t o insufficient condensation. ( b ) Temperatures measured b y pyrometer attached t o wall of tube
+
3i:i
E
1.0
:;.
not be determined with the facilities at hand. The percentage ol' loss was not of so much moment in these experiments as was 1
XI'. F. Rittman. THISTOURNAL, 7 (1915). 945.
Apr., 1916
T H E J O C R , Y A L OF I N D U S T R I A L A N D E N G I N E E R I X G C H E J f l S T R Y
1'11..
1 1 1 ~~si0 ~ ~ ~RATES X S OF OIL Fsaocb) PROM
corsrANT P ~
V~aut
WITII
5
I
mn
ii
I < i l , i S < I P Oil. I
OIL RS-
SINCLE-TUBT. I i i i x h . ~ c (TUBE ~ 6
mNC) AT
2
PoanlZo
I I
s
600
is0
AXl>
E
Gal.
Temp. 0
c.
550 550 550 57.5 600 600 600 625
Oil ~ e hr. r
17 19
26 13 17 19
23 22
6.50
19 21
6.5"
2.5
610 ~~~
~
(o)Bolling point 2 5 0 O t o 350' condensation.
C.
(b1ReruIts IDW.
due to insufficient
EXPERIMENTS WITH 8-IN. X IO-FT. TUBS
The same oil was cracked in a number of experiments in an 8-in. X io-it. tube. The data are assembled in Table IX. The average percentage of gasoline formed is only 18.8 as compared with 19.j in the smaller tube. In the larger tube the average rate of feed was increased from 2 2 gal. to 30 gal. per hour. The greater volume of gases generated placed a heavier burden upon the already inadequate condenser, which contributed to the average lower yield obtained. The low percentage of gasoline formed is, in the majority of yields reported in this table, clearly due to the excessirc rate of feed, which did not allow sufficient opportunity for conversion.
I
I
COXCLUSIONS AS To GASOLINE TRSTS-I~ considrring the figures assembled in the foregoing tables, it must bc remembered that efficient condensation was lacking. The work was carried on during intervals when benzene-toluene experiments were being conducted with equipment erected to obtain indications I n.. F. ~ i t t m ~ 'rHIs n. JWRX.N.. T ( I ' J I T ~ . 945.
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
Apr., 1916
as to benzene-toluene reactions, and not t o determine maximum yields. Accordingly the condensing facilities were of the crudest type. The results can be considered only as suggestive of TABLEX-GASOI,INE FORMED FROM CRACKING A DIBTILLATE FUEL OIL IN A SINGLE-TUBE FURNACE (TUBE 8 IN. IN DIAMETER AND 10 FT. LONG)AT A CONSTANT PRESSURE OF 250 LBS. PER SQ. IN., WITH VARYING TEMPERATURES AND RATESOF OIL FEED(^) Gal. GASOLINE Oil OIL RE- Per cent in Per cent on Temp. per COVERED Recovered Basis of Sp. OC. hr. Per cent Oil Original Oil Gr. 22.5 75 30.0 .... 12 19.8 79 2.5. 1 15 22.2 71 31.3 0.76 12 30.8 40.0 0.72 77 12 28.9 38.5 0.75 75 16 26.8 74 0.75 36.3 12 17.6 .... 88 20.0 15 26.0 0.78 80 30.5 15 (a)Results low, owing to insufficient condensation. .
.
I
.
what can be accomplished under proper conditions. Viewed in this light they are of a distinctly favorable character, and justify belief in the commercial possibilities of the process. GASOLINE PROCESS COMPARED W I T H B E N Z E N E - T O L U E N E PROCESS
I n comparison with t h e benzene-toluene process, t h e gasoline process is simple in character. This m a y be more readily perceived by considering t h e order of hydrocarbon reactions as given below. T h e relative order is n o t only based o n t h e o r y , b u t is in accordance with t h e evidence’ gained as t h e result of extended series of tests.l ORDER OB HYDROCARBON REACTIONS
1 I
=
for conversion of h e a v y oil i n t o gasoline. T h e duration of t h e gasoline reaction is less t h a n half t h a t required for t h e benzene-toluene reaction if t h e s a m e size a n d length of t u b e s be used. It is manifest, therefore, that b y introducing twice t h e volume of oil t o b e converted, t h e effect will be t h e same as decreasing t h e t i m e factor by one-half. CONCLUSIONS AS TO GASOLINE PROCESS
.
Distillation Analysis of Original Oil Used [Specific gravity, 0.915 (23’ B . ) ; first drop at 300’ C.] Temperature DISTILLATION PRODUCT of Cut Volume yo of SpeciGc OC Cc. Original Oil Gravity 350 85 42 0.8; 400 80 40 Jelly-hke
H e a v y petroleum Hydrocarbons 1
341
1
Light petroleum Hydro(carbons (saturated a n d (unsaturated)
JE. Cymene, etc.
Jb Xylene
i b Toluene
i\ Benzene
T h e large-scale experiments have fully coAfirmed t h e laboratory experiments a n d established t h e f a c t t h a t t h e conversion i n t o gasoline can be even more satisfactorily accomplished in a t u b e of greatly enlarged diameter a n d increased length t h a n in t h e electrically h e a t e d I I/2-inch t u b e . T h e conditions favorable for gasoline production a r e shown t o be t h e . same in t h e larger t u b e s as in t h e small t u b e , namely, a t e m p e r a t u r e of approximately j o o o t o 5 7 5 ’ C. a n d a preQure of 2 5 0 t o 300 lbs. per sq. in. T h e gasoline process, therefore, can justly be considered as a success so f a r as conversion in t h e large tubes is concerned. T h e a d a p t a t i o n of t h e unit t o refinery conditions is a m a t t e r of mechanical detail involving no inherent difficulties. SUCCESS O F B E N Z E N E - T O L U E N E PROCESS
I n view of t h e continuous operation of the benzenetoluene process by t h e A e t n a Explosives Co., over a period of nearly one year, as well as t h e results of t h e large-scale operations, which h a v e been given in detail, t h e r e can exist little d o u b t as t o t h e success of t h e benzene-toluene process on a commercially operat i v e scale. It has been proved t h a t benzene a n d toluene can be produced in .large quantities b y t h i s process. These products have been shown t o be capable of being worked i n t o t h e nitro-compounds desired for making explosives. Furthermore, these nitro-compounds, or t h e derivatives thereof, a r e equally suitable for use i n producing dyestuffs. T h e claims which were m a d e for t h e process at t h e outset have t h u s been fully verified b y commercial results, a n d its f u t u r e is dependent alone upon t h e perfection of t h e mechanical a p p a r a t u s a n d t h e conseq u e n t reduction in labor a n d operating costs.
J\ Naphthalene, Diphenyl, etc.
Jb Anthracene, etc.
BUREAUOF MINES,WASHINGTON
A TEST OF A SURFACE COMBUSTION FURNACE’ B y E. SCHRAMM AND J. R. CAIN Received February 2, 1916
Jb C a r b o n and Gas T h e conversion f r o m h e a v y hydrocarbons i n t o lighter hydrocarbons involves only one s t e p , a n d is easy of accomplishment, whereas t h e conversion i n t o t h e lower boiling aromatic hydrocarbons requires t h a t t h e heavier hydrocarbon molecules undergo a much more extensive series of changes before t h e desired products are obtained. Because of t h e greater ease with which gasoline can be made, t h e installation used for benzene-toluene production will have double t h e capacity when used Rittman, Byron and Egloff, THIS JOURNAL, 7 (1915). 1019.
I n a n article on “ T h e Design of Surface Combustion Appliances,” Prof. C. E. LuckeZ gives a n account of t h e principles underlying this new process of combustion, a n d of their application t o t h e development of commercial a p p a r a t u s . T h e surface combustion process has aroused considerable interest a n d given rise t o much speculation since its first publication in 1 9 0 2 . ~ For a diversity of views as t o its 1
Published with the permission of the Director of the Bureau of Stand-
ards. 2 C. E. Lucke, THIS JOURNAL, 6 (1913), 801-24; Proc. Amer. Gas. Inst., 8 (1913), 420-504. a C. E. Lucke, Trans Amer. SOC.M e c h . Eng., 28, 253-262.
