Pvrolvsis and Polvrnerization of Gaseous Paraffins and Olefins J
J
J
NOWLE D GE
@K
pane, c o n s i d e r a b l y more deResults obtained in the pyrolysis of of the reaccomposes t o form ethylene and ethane and propane at atmospheric presm e t h a n e than propylene and tions insure in helical KA2S tubes are presented. hydrogen. A number of secvolved in the pyrolytic decomUnder optimum conditions about 74 per ondary reactions also occur durposition and p o l y m e r i z a t i o n cent by volume of the ethane charged was ing the p y r o l y s i s of paraffins; of gaseous h y d r o c a r b o n s is two of the more important are fundamental for an understandconverted to olefins and the maximum ing of t h e m e a n s b y w h i c h (a) complete d e com p osi t i o n yield in the case of propane was 82 per cent. with the formation of carbon these hydrocarbons may be conOwing to the fact that a major portion of a n d h y d r o g e n , a n d (b) converted to higher boiling liquids. the propane reacting formed ethylene and densation of the olefins formed T h e l i t e r a t u r e dealing with methane, the weight yield of olefins from to aromatic liquids. the thermal decomposition of paraffins (and olefins) is extenthis charge was appreciably lower than the In the pyrolysis of ethane and p r o p a n e best results were obsive and has been reviewed by volume yield. tained when using a reactor conEgloff, Schaad, and LOWTY( 3 ) . The polymerization of pure ethylene and sisting of a helical coil of KA2S The l i t e r a t u r e d e a l i n g with tubing. An 18-foot (5.5-meter) pure propylene in the pressure range 500 to the polymerization of olefins a t length of this tubing, having an 3000 pounds per square inch at temperai n t e r n a l diameter of 6/18 inch superatmospheric p r e s s u r e is (8 mm.) was coiled into a helix meager, but mention should be tures varying from 650' to 850' F. (343' to having a mean diameter of 3.6 m a d e of t h e e a r l y w o r k of 454' C.) and times of contact of from 1 to inches (81 mm.) a b o u t 14 f e e t Ipatieff ( 4 ) , and the l a t e r i n (4.25 meters) of the tube being in 105 minutes is described. Liquid yields of the coiled p o r t i o n , the volume vestigations of Stanley (7), Nash, 70 to 80 per cent, based on the ethylene of which was 15.4 cubic inches Stanley, and Bowen ( 5 ) , Pease (252 cc.). This reactor was placed charged, were obtained under optimum (6),Waterman and T u l l e n e r s in a r a d i a n t - t y p e electrically (8), and the very informative conditions; the major portion of the liquid heated furnace, temperatures being read by means of six thermocouples articles ,by Dunstan, Hague, and produced fell within the motor-fuel boiling peened to six turns of the coil. T o Wheeler (1) and by Egloff and range. From 60 to 65 per cent of the proreduce radiation effects as much as Schaad (2). possible, the thermocouples were pylene charged was converted to liquid unThe production of liquid hyattached to the tube surface formder optimum conditions. ing the inside of the helix. drocarbons from gaseous parafThe charge mas passed from fins by a one-step process, instorage through a calibrated flowrolving simultaneous pyrolysis meter to the reaction coil which F. W. SULLIVAN, JR., R. F. RUTHRUFF, and condensation a t high temwas at atmospheric pressure in A N D W. E. KUENTZEL all cases. The reaction products peratures a n d a t m o s p h e r i c were shock-cooled and measured pressure, has been studied by Standard Oil Company (Indiana), either by a meter or by collecting many investigators, as has the in a calibrated gas holder. The Chicago, Ill. condensation of pure olefins at olefin content of the various gas samples was determined by abhigh temDeratures and atmossorption in fuming sulfuric acid using a Rurrell gas analysis pheric pressure. In all of this work, the liquid produced was apparatus and a Francis automatic bubbling pipet. The olefins highly aromatic; about half was in the motor-fuel boiling were removed according to a definite routine procedure during range, and the remainder consisted of condensed aromatic which a small amount of the paraffin reacted with the acid. To determine and correct for the paraffins so destroyed, the same hydrocarbons. This work is summarized in the two literasample was again subjected to the same procedure; the contracture reviews mentioned (9). Preliminary experiments intion observed during the second analysis was taken t o represent dicated that such one-step processes were inferior to the twothe paraffins reacting in the fist, and the initial analysis was corstep process involving first, the thermal decomposition of the rected accordingly. The density of the cracked gas was determined by means of an paraffins at atmospheric pressure with the formation of olefins, effusiometer, and in most cases the molecular weight of the oleand secondly, the polymerization of the olefins a t superatfins formed was calculated by absorbing the olefins from a large mospheric pressure to produce liquids. For this reason the sample and determining the density of the olefin-free gas. Time two-step process only is considered in the following. of contact was calculated by dividing the average of the inlet and exit gas rates, corrected for the indicated mean reaction temperature, into the reaction volume. The volume increase reported is Thermal Decomposition of Gaseous Paraffins the increment of the exit over the inlet flow rate, expressed as a percentage of the inlet rate. Volume per cent conversion to In the thermal decomposition of any paraffin higher than olefins was determined from the formula: , ethane, two primary reactions occur; the first involves the B rupture of the molecule cracked with the formation of a lower Volume per cent conversion = (100 A ) zo paraffin and lower olefin, and the second involves simple de\There A = volume increase, per cent hydrogenation with the production of a n olefin containing B = olefins in exit gas, volume per cent the same number of carbon atoms as the original paraffin: This value is obviously the number of volumes of olefins produced CnH,ri + 2 +Cn - A n - .z C ~ H+Zz ~ per hundred volumes of feed. CnH2n + 2 +CnHm H2 The data obtained in twenty runs charging ethane are As the homologous series is ascended, the first reaction besummarized in Table I ; the trend of the more important comes increasingly important; but even in the case of pro7 072
-
+
+ +
SEPTEhlHER, 1935
INDUSTRIAL A S D ENGIhEEKIUG CIIE\.IISTRY
1073
and 6. In Table I1 both the weight per cent and volume per cent yield of olefins arc shown, for in the pyrolysis of propane the charge may react to form either propylene and hydrogen or ethylene and methane. The volume yield is about 1.35 to 1.45 times as great as the olefin yield calculated on the weight basis, and this ratio apparently does not change in any regular manner with variations in temperature, time of contact, or conversion. Q u a l i t a t i v e l y , t h e data obtained in the pyrolysis of propane are similar in all respects to the corresponding ethane results. A plot of volume per cent conversion of p r o p a n e to olefins against per cent v o l u m e i n c r e a s e is satisfied by one curve regardless of the time CONYEPSION To OLEr NS-KXUME PER CENT FIGURE 1. VOLUMEINCREASEus. FIGURE 2. UNSATURATES IN EXIT and conditions to ObCONVERSION TO OLEFIIWIY ETHANE GAS US. TINE OF CONTACT IN tain the individual points. T h e d e v i a t i o n PYROLYSIS ETHANEPYROLYSIS of this curve from the t h e o r e t i c a l is q u i t e small but increases with increasing rapidity as conversion increases. At 50 per cent conversion, volume increase is theoretically 50 per cent; actually it was found to be 55 per cent, With 75 per cent of the charge converted to olefins, the volume increase was 91 instead of 75 per cent, while the volume increase is actually 104 per cent (instead of 80 per cent) when the volume per cent yield of olefins is 80 per cent. As shown by Figures 4 and 5, the olefin yield (by volume) and the olefin content of the cracked gas are both maximum when operating a t high temperatures and short contact times. Under such conditions the cracked gas contained 40 per cent FIGCRE 3. COVVERSIOX TO OLEFINS us. TIMEOF olefins, equivalent to an olefin yield (by volume) of about CONTACT IN ETHANE PYROLYSIS 82 per cent. On increasing time of contact beyond that necessary for optimum results, the olefin content of the variables is shown graphically in Figures 1, 2, and 3. In cracked gas and the olefin yield both decrease because of destruction of the olefins through secondary reactions. Figure l the volume per cent conversion of charge to olefins is plotted against the per cent volume increase. In the absence of secondary reactions, volume increase is numerically Polymerization of Gaseous Olefins euual to the volume yield of olefins and, as Figure 1 shows. the deviation of experimental points from the theoretical curve The equipment employed in the polymerization of pure is quite small but increases with increasing conversion. This olefins a t superatmospheric pressure consisted of a low-presfigure also demonstrates that temperature, per cent conversure gas storage system in which fresh gas was held, two sion, and time of contact per se have little influence on the three-stage compressors by means of which the feed gas course of the reaction. Table I shows that, while times of was compressed to a pressure equal to that a t which the excontact of 0.5 to 2.6 seconds were employed in the temperaperiment was to be run, a high-pressure storage system to ture range 1440' to 1550' F. (782' to 843' C.), one curve on accommodate the compressed gas, and finally the polyFigure 1 represents all the data obtained, with two exceptions merizing bombs themselves. These bombs had a reaction where secondary reactions were pronounced. space 10 inches (25.4 cm.) long and 2 inches (5.1 cm.) in In Figure 2 the ole& content of the exit gas is plotted against time, and it is apparent that T A B L E I. ETH.4NE PYROLYSIS I N KAPS COIL the greatest olefin concentration (39 per cent) is Arithmetic Mean Time obtained by operating a t very high temperatures Val. Conver- of Reaction Inlet and very short contact times. Volume per cent "N",: &&,, Temp. Gas --Exit Gas-Increase sion Contact yield of olefins is plotted against time of contact % UnsatuMol. in Figure 3. Under optimum conditions 74 per F. Sec. C. F. C . L./min. L./min. rates % Vol. % wt. cent of the charge was converted to olefins in 55 1430 40.5 39.5 0.80 28.1 20.9 777 1436 780 3.98 5.59 4 3 . 3 0 .85 2 9 . 6 2 1 . 0 4 6 . 2 774 1440 782 3 . 8 3 5 . 6 0 50 1425 one pass. These figures demonstrate that olefin 50.7 48.1 1.38 58 1432 778 1436 31.9 20.0 780 2.22 3.35 yield and olefin content of the cracked gas in54 46.8 46.2 1.47 1428 776 1430 31.5 19.8 777 2.12 3.11 49.0 51.1 1.48 53 1443 784 1445 34.2 19.5 785 2.13 3.18 at any given temperature with increasing 51 1428 776 1436 780 1.82 51.5 1.69 32.6 1 9 . 0 58.0 2.88 19.3 42.5 43.0 , 2.5 30.2 769 1421 772 1.28 1.83 1417 time of contact until optimum conditions are 56 2.6 52 1441 783 1445 17.0 70.0 47.8 785 1.14 1.94 28.2 reached, after which a further increase in time of 57 1420 771 1423 773 1.17 1.81 31.2 1 9 . 4 55.0 48.3 2.6 58.0 52.6 0.50 33.2 20,O 802 1494 812 6.06 9 .60 contact results in decreased olefin yield and lower 42 1476 40 1500 816 1502 817 4.94 8.15 34.1 19.8 65.0 56.2 0.54 olefin concentration in the cracked gas. This de59 1486 80s 1494 812 4.55 7.06 33.6 19.5 55.0 52.1 0.65 43 1477 803 1490 810 4.04 6.66 35.5 64.6 58.5 0.73 crease is due to the destruction of olefins through 49 1486 sos 1496 813 3 . 7 8 6 . 4 4 3 4 . 9 1 8 : s 7 0 . 5 5 9 . 5 0.76 secondary reactions; part decomposes to form 2: ii:: f::: 3":;: 66.5 65 79 ..73 01 ., 84 5 2 carbon, hydrogen, and methane 45 1529 832 1550 843 5 . 8 9 10.42 39.2 18.3 77.0 69.4 '0.47 47 1534 834 1552 844 4.00 7.60 39.0 1 6 . 8 90.0 7 4 . 1 0.65 portion condenses to form aromatic liquids. 71.3 0.66 46 1514 823 1530 832 4.06 7.45 38.8 17.7 83.0 Similar data obtained in the pyrolysis of pro48 1558 848 1571 855 1.99 3.89 32.2 15.4 96.0 63.1 1.27 pane are shown in Table I1 and Figures 4, 5,
;::: z;:
IXDUSTRIAL AND ENGINEERING CHEMISTRY
1074
VOL. 27, NO. 9
T ~ B L1E 1. PROPANE PYROLYSIS IN KAZS COIL Run
No.
F.
3 2 1 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 32 33 34 35 36 37 38
Mean Reaction Temp.
Arithmetic Av. Temp.
1208 1222 1237 1259 1282 1307 1344 1372 1369 1376 1404 1427 1443 1450 1444 1456 1471 1479 1474 1465 1479 1491 1496 1477 1489 1501
O
C.
653 661 669 682 694 708 729 744 743 747 762 775 784 788 784 791 799 804 801 796 804 811 813 803 809 816
F. 1260 1246 1247 1310 1305 1313 1407 1412 1410 1403 1412 1466 1465 1460 1498 1494 1495 1497 1491 1503 1497 1505 1505 1486 1499 1508
C.
682 674 675 710 707 712 764 767 766 762 767 797 796 793 814 812 813 814
811 817 813 818 818 808 815 820
Inlet Gas
L./?nin. 5.96 3.98 2.01 5.72 4.02 1.96 8.30 6.30 6.34 4.20 2.13 6.59 4,l3 2.17 8.28 6.36 4.24 2.07 2.73 8.16 4.23 2.71 2.17 6.19 4.13 2.43
I
L./min. 6.82 4.61 2.46 7.36 5.16 2.81 11.4 9.18 9.14 6.4 3.72 10.62 7.06 4.13 14.48 11.71 8.29 4.31 5.47 14.70 8.26 5.54 4.56 11.33 8.30 5.18
Exit Gas % unsatu- Mol. rates
11.0 11.7 15.0 17.4 20.4 24.4 27.1 29.7 29.9 30.1 37.0 36.0 38.5 39.6 37.6 38.4 39.5 38.2 39.6 38.0 39.2 39.4 37.6 37.9 40.2 38.5
wt. 35.7 35.8 34.0
.. ..
.. 30.0 28.5 28.5 27.0 23.8 25.0 24.3 22.5 25.5 24.8 22.6 20.4 21.6 25.0 22.2 20.6 19.8 Ca25 23.0 (2822
Vol. . Increase Mol. wt. olefins
%
34.6
14.5 14.8 22.2 28.6 28.5 43.4 37.5 45.6 44.6 53.5 74.5 61.1 71.0 90.2 75.0 84.3 95.4 108.0 100.2 80.0 95.2 104.0 110.0 83.0 101.0 113.0
..
31.6 31.6 32.1 32.8 32.2 32.2 33.5 31.6 30.3 32.4 31.5 32.3 34.1 30.2 30.4 29.8
..
.. ..
.. ..
-Conversion---
VoZ. % 12.6 13.6 18.3 22.4 26.2 39.3 37.2 43.3 43.3 46.2 64.6 58.0 65.8 75.2 65.8 70.8 77.1 79.5 79.3 68.4 76.4 80.1 79.0 69.4 80.8 82.1
Time
Wt. % ' 9.9 12.7 16.1 18.8 28.7 27.7 31.7 35:2
..
40.0 48.5 53.4 48.3 54.8 53.0 55.0
.. .. .. .. .. ..
.. ..
See. 0.71 1.03 1.90 0.67 0.94 1.78 0.42 0.53 0.53 0.77 1.39 0.48 0.71 1.25 0.35 0.43 0.62 1.21 0.95 0.34 0.62 0.94 1.14 0.45 0.62 1.01
so prepared indicated that they were about 95 per cent pure. In carrying out an experiment, the bomb was heated as rapidly as possible to the desired operating temperature, a low flow of the charge being maintained during this period. When the operating temperature was reached, the flow was increased to the predetermined desired value after which all conditions were maintained as constant as possible. The exit products, after reduction of pressure and cooling, were passed through a separator from which the liquid was withdrawn from time to time. No attempt mas made to remove butanes or higher components from the gas leaving the separator. As is well known, the polymerization of olefins is highly exothermic. If the heat evolved is not dissipated, the operating temperature will rise, thus increasing the velocity of polymerization; this in turn will result in an even more rapid evolution of heat. The exothermic character of the polymerization reaction has been observed by many investigators in this field; in fact Waterman and Tulleners (8) state that "ethylene a t a temperature above 350" C. and under a pressure of 175 kg. per sq. em. (ea. 175 atmospheres) decomposes with explosive violence." Fortunately, this was not found to be the case, but in many experiments the temperature "ran away." In one run, for example, the temperature began to rise and continued to rise after the heat input to the bomb was stopped. After reaching 1200' F. (649" C.), the temperature r e m a i n e d c o n s t a n t for 2 hours, after which it gradually receded. On opening the bomb, it 75 was found t o be filled with carbon. Data on the polymerization of " 5 e t h y l e n e a n d propylene a r e presented in Table 111. All operating conditions are shown and, in addition, the capacity of the experimental units as measured by the liquid production per hour and the weight per cent liquid yield based on t h e weight of olefins charged. Inspections on the various polymers a r e given, includTIME OF CONTACT- SECONDS TIME OF CONTACT-SECONDS ing the gravity, the per cent overFIGURE 6. CONVERSION OF OLEFINSus. FIGURE 5. UNSATURATES IN EXITGASus. IN PROPANE PYROLYSIS head a t 392" F. (ZOOo C.) when TIMEOF CONTACTIN PROPANE PYROLYSIS TIMEOF CONTACT
diameter, and were provided with a thermocouple well together with appropriate connections for the entrance of feed and the removal of polymer and unpolymerized gas. The bombs were externally heated. High- and low-pressure condensers w e r e provided for the removal of liquid from the exit gas s t r e a m , and the r a t e of e x i t gas flow was measured by a suitable flowmeter. The o l e fins were prepared b y t h e dehydration of ethyl alcohol or i s o p r o p y l ether by passage over coke satur a t e d with phosphoric a c i d , a t e m p e r a t u r e of 550" F. (288" C.) COWON To OLEFINS-VCLUME PER CENT being employed. FIGURE4. VOLUME INCREASEus. Repeated analyses CONVERSION TO OLEFINS IN PROPANE of the two olefins PYROLYSIS
INDUSTRIAL AND ENGINEERING CHEMISTRY
SEPTEMBER, 1935 TABLE111.
POLYYEItIZdTlON O F
ETHYLENE .4XD
1075
PROPYLENE oc..
tane Grav. Per Cent Grav. No. Time of off of of of PresConver- Prodat Gaso- GasoTemperaRun ture Contact ' sure Liquid sion uct 392' F. line line NO. F. C. Min. L b . / s q . in. Cc./hr. Wt. % ' A . P . I . 'A.P.T Ethylene 2.2 3.1 52.5 72.4 55.7 9.3 500 750 399 4435 6.7 16.2 52.7 2223 18.0 73.1 57.6 751 399 8.0 6.0 52.6 80.0 56.5 802 428 4.6 421 16.2 19.2 52.2 75.6 58.1 76 8.5 800 427 3335 1 7 . 0 34.0 51.6 72.3 58.8 801 427 16.0 74 5534 27.0 8.9 51.1 78.4 453 2.1 55.8 77 848 5533 853 456 4.1 30.3 20.6 52.0 79.5 57.9 78 420 5521 851 455 8.1 38.7 59.1 49 0 73.8 58 1 .. 6.1 5.0 43.0 27.0 56.2 371 9.7 1000 72 317 700 5 . 2 7.0 50.4 53.7 56.1 19.2 372 3333 701 7.2 17.3 51.4 59.3 57.5 372 36.8 75 702 3334 5.4 52.4 15.9 63.2 56.9 399 4.5 76 5532 751 13.1 45.0 58.2 17.6 46.3 9.1 399 750 416 25.8 27.7 62.3 63.0 58.3 17.4 72 399 751 3332 50.6 50.2 60.2 59.3 33.2 399 31.6 70 751 5530 24.6 84.6 51.8 67.3 58.9 4.2 72 553 1 80 1 427 30.8 52.7 69.2 60.6 8.4 49.1 72 427 800 517 55.2 50.0 65.5 76.5 59.8 427 14.7 801 70 322 67.8 61.2 59.6 51.6 28.9 40.6 428 802 71 4432 39.2 50.5 167.5 69.1 59.5 454 3.8 71 850 4433 42.1 61.7 71.4 61.1 454 7.7 76.2 850 318 58.7 46.9 455 13.6 87.6 68.6 59.7 851 68 520 70.0 41.5 49.3 69.5 60.9 454 27.4 850 5529 70 .. 372 9 . 6 2000 7 . 8 4 . 8 5 1 . 3 5 1 . 6 5 9 . 0 702 5526 18.7 35.3 21.6 47.8 38.5 518.4 699 371 57.1 73 42.2 41.7 371 35.2 47.7 39.4 57.7 516 700 67.2 32.7 53.8 .. 372 49.1 42.5 60.1 701 5523 50.5 23.2 399 52.6 61.2 60.2 9.0 3326 250 68 399 87.7 46.3 49.9 49.6 59.8 16.6 72 515.4 I 51 398 86.0 61.6 49.0 30.0 3325 748 50.7 60.1 63 33.4 63.0 4427 750 399 65.7 51.6 61.4 61.2 66 63.2 428 18.9 54.1 70.2 4.4 60.0 3329 803 63 428 49.1 53.1 8.0 146.4 5524 803 66.5 61.2 67 181.1 6 6 . 7 802 428 49.0 56.7 61.6 14.3 315 62 426 49.1 26.8 121.8 72.3 4426 798 61.9 61.7 62 427 73.2 51.6 68.5 61.3 59.5 33.1 4428 800 65 454 36.4 54.4 4.8 154.2 850 71.4 60.8 63 3328 54.4 131.4 456 52.6 73.1 60.9 7.8 3327 852 66 454 48.6 74.5 15.5 67.5 5525 850 69.3 60.8 65 451 22.4 844 48.0 62.5 80.8 60.2 .. 186.3 5522 454 69.3 61.9 17.4 4429 850 50.6 74.2 59.4 63 14.7 3000 16.5 7.5 344 47.7 33.8 58.8 70 2227 651 27.7 19.5 343 45.0 26.9 28.9 57.8 2228 650 69 343 45.1 26.9 56.6 26.3 31.5 57.8 1129 650 71 343 111.4 16.2 41.8 47.4 36.1 59.1 1128 650 70 372 46.2 28.3 78.7 19.5 7.1 57.7 3324 701 39.3 17.4 13.8 372 50.6 47.8 61.2 3337 702 68 26.3 100.0 43.1 370 44.6 26.9 698 58.9 321 69 373 49.2 53.1 50.3 51.6 40.8 61.1 703 4438 66 75.0 85.0 75.0 373 46.5 40.2 61.4 703 1125 62 395 40.5 6.5 46.4 282.9 47.1 58.8 743 4425 399 48.6 41.5 12.0 54.6 239.0 60.7 750 3601 70 402 44.3 19.9 73.0 324.5 46.2 61.5 755 62 519 401 95.0 47.5 47.3 753 43.0 74.8 4437 62.3 63 399 48.7 54.4 78.8 75.7 2224 65.1 62.1 751 63 428 48.0 144.0 6.0 39.8 59.0 54.4 803 3336 78 312.6 43 1 47.7 55.3 808 74.3 17.3 62.5 62 4436 455 49.4 85 1 59.3 451.0 5.3 64.2 61.1 63 1126 452 50.1 67.1 344.0 71.4 9.6 845 61.3 63 2225 72.2 22.6 75.4 49.1 68.7 61.0 1127 85 1 455 68
..
..
3345 4607 3346 5547 5546 5548 4447 5537 3338 4441 3340 4440 3339 3348 4446 3344 5545 4445 3342 5549 5544 4444 5543 3605 5542 4450 3341 4602 5539 4442 4603 3443 5538 4604 5540 5541
750 801 800 850 851 850 851 751 800 800 800 850 850 700 702 701 748 750 751 750 800 802 805 849 852 849 697 701 751 752 751 802 800 800 854 844
399 427 427 454 455 454 455 399 427 427 427 454 454 371 372 372 398 399 399 399 427 428 429 454 456 454 369 372 399 400
399 428 427 427 457 451
14.5 6.5 13.4 1.8 3.4 3.4 5.7 4.1 3.8 11.2 22.6 3.3 6.2 18.2 25.8 54.2 7.7 13.5 22.1 28.6 6.4 11.1 16.9 3.4 5.9 10.6 22.8 35.4 6.4 17.1 27.3 5.4 8.8 16.4 5.3 8.7
Propylene 1.3 4.9 7.2 11.1 25.0 15.5 24.5 1000 8.2 25.0 49.1 45.6 100.0 107.0 2000 10.8 17.0 22.5 53.6 70.8 75.4 94.3 282.0 220.4 199.3 368.7 368.6 239.0 3000 34.8 51.4 109.0 225.0 207.2 551.0 473.0 262.0 450.0 397.0 500
2.2 3.7 11.0 2.4 10.3 6.0 16.3 1.8 5.5 27.5 46.9 22.9 38.1 5.6 11.6 29.1 11.1 24.0 38.9 51.0 41.7 53.9 64.0 32.7 48.5 62.8 13.8 27.9 12.7 49.8 62.6 43.0 56.2 61.0 43.4 61.2
52.7 54.2 52.1 52.7 54.9 49.4 53.2 53.0 56.2 54.5 53.6 55.5 54.9 48.1 51.9 52.2 53.1 55.0 54.7 50.2 i3.9 04.1 53.4 53.6 52.4 49.8 53.5 53.1 53.8 53.1 52.7 53.3 52.1 52.5 49.5 50.3
73.8 81.3 77.5 81.2 82.3 78.3 80.3 68.6 79.6 75.7 73.1 79.9 76.7 51.1 58.8 59.0 65.1 67.3 65.4 56.1 70.1 68.1 69.5 70.7 70.3 66.2 57.8 57.2 61.1 60.5 59.5 63.4 63.3 63.4 67.4 67.1
54.8 55.4 54.9 54.4 56.7 52.4 56.3 55.9 57.4 58.0 59.1 57.5 58.2 53.9 67.8 58.7 57.4 59.6 60.2 58.1 59.6 59.8 60.3 58.8 59.2 59.1 59.7 60.1 58.5 60.1 60.6 59.4 59.9 60.3 58.5 59.1
.. .. .,
., 80
..
78 86.5 80 86 87 86 87
..
75 79 76 79 79 75 74 75 75 74
78 75 82 80 75 78 79 74 74 74
1. Ethylene a t 850" F. (4540 C.) Propylene a t 850' F. (4540 C . ) 3. Ethylene at 800' F. (4270 C.) 4. Propylene a t 800°.F. (4270 C.) 5. Ethylene a t 750' F. (3990 C.) 6 Propylene a t 750' F. (399" C.) 2.
LI
TIME OF CONTACT-MINUTES
i
FIGURE7. P O L Y M E R I Z A T OF ION ETHYLENE .4ND PROPYLENE A T 500 POUNDS PER SQUARE INCH PRESSURE
6
c 2 I
Y
, 6-
2 4
Y
L
ay z
w 82
$ U
TIME OF CONTACT-MINUTES
FIGURE 8. ENE
1. 2. 3. 4. 5. 6.
AND PER
POLYYERIZATIOV O F ETHYL-
PROPYLENE AT 1000 POUKDS SQUARE INCHPRESSURE
Ethylene a t 850' F. (454' C . ) Propylene at 850' F. (454' C . ) Ethylene a t 800' F. (427' C . ) Propylene a t 800' F. (427' C . ) Ethylene a t 750' F. (399' C.) Propylene a t 750' F. (399' C.1; ethylene a t 700' F. (370' C . )
distilled through a Hempel column together with the gravity of this overhead product which was called gasoline. The knock ratings of the gasoline fractions (C. F. R. Research) are given in many cases. The effect of time of contact on the weight per cent conversion of ethylene and propylene to polymer a t 500 pounds per square inch pressure and in the temperature range 750" to 850" F. (400" to 455" C.) is shown graphically in Figure 7. The amount of entering ethylene converted to liquid a t constant temperature increases with increasing contact time, reaching a maximum of 59 per cent by weight a t 850" F. (455" C.) a t 8 minutes time of contact. The ethylene polymers produced a t t h i s p r e s s u r e had g r a v i t i e s of about 52" A. P. I. and contained 75 to 80 per cent gasoline having research knock ratings of 74 to 78 octane number. 'The liquid conversions in propylene experirnents were not so great as in ethylene experiments carried out under the same conditions, the isotherms for propylene being below the c o r r e s p o n d i n g ethylene isotherms. The propylene p o l y m e r s had gravities of 52" to 54" A. P. I. and contained from 75 to 82 per cent gasoline by volume,
INDUSTRIAL AND ENGINEERING CHEMISTRY
10i6
the knock rating of the gasolines varying from 78 to 80 (C. F. R. Research). The influence of contact time on polymer yield a t 1000 pounds per square inch pressure is shown in Figure 8 ; data from several ethylene runs and six propylene runs a r e included. With ethylene, conversion t o liquid increased with i n c r e a s i n g t i m e , t h e maximum liquid yield being 70 per cent obtained a t 850" F. (455" C.) with a contact time of 27 minutes. The polymers formed in the various exn M E OF CONTACT-MINUTES periments had, in FIGURE 9. POLYMERIZATION OF general, gravities ETHYLENE AND PROPYLENE AT 2000 of 48" to 52" A. POUNDS PER SQUARE INCHPRESSURE P. I. and usually contained 69 to 70 2. Ethylene a t 800' F. p e r c e n t gasoline 3 . Propylene at 800' F. of 68 to 76 octane 4. Ethvlene a t 750" F. number (C. F. R. Research). T h e p r o p y l e n e polymers formed under similar conditions had gravities of 53" to 55" A. P. I. and contained 70 to 80 per cent gasoline of 86 to 87 octane number (C. F. R. Research). The polymer yield from propylene is again appreciably lower than the corresponding ethylene yields. More attention was given to the polymerization of the two olefins a t 2000 and 3000 pounds per square inch than a t the lower pressures. The data obtained a t 2000 pounds for both ethylene and propylene are shown in Figure 9. Conversion increases rapidly with increasing contact time up to a maximum; beyond this point, further increase in time of contact results in little or no increase in liquid yield. With
VOL. 27, NO. 9
ethylene a t 800" F. (427" C.), conversion was 67 per cent a t 14 minutes, 72.3 per cent,at 27 minutes, and only 73.2 per cent after 59.5 minutes. At 850" F. (455" C.) increasing contact time beyond 22 minutes resulted in lowered yields of liquid, indicating that polymer destruction by cracking was proceeding more rapidly than polymer formation by polymerization. A liquid yield of 81 per cent was observed a t 850' F. and 22.4 minutes which decreased to 69 per cent on increasing contact time t o 62 minutes. The ethylene polymers produced a t 2000 pounds pressure had A. P. I. gravities varying from 48" to 54" and contained (in the higher temperature range) from 60 to 70 per cent gasoline with research knock ratings of 65 octane number. Propylene a t 2000 pounds pressure formed polymers having A. P. I. gravities of 50" t o 55" and containing from 65 to 70 per cent gasoline of about 75 to 80 octane number (C. F. R. Research). The effect of time of contact on polymer yield for operation a t 3000 pounds per square inch is shown in Figure 10. It is again evident that liquid yield increases with increasing time of contact to some maximum value, after which further increases in time of contact result in no further increases in liquid yield. The various ethylene polymers had gravities of 45' to 50" A. P. I. and contained from 25 to 70 per cent gasoline of 63 to 70 octane number (research). The propylene polymers were of 50" to 55" A. P. I. gravity and contained about 57 to 67 per cent of 75 octane gasoline. OF PRESSURE ox ETHYLENE AND PROPYLENE TABLE IV. EFFECT POLYMERIZATION
oc-
tane
I
Charge Ethylene
Propylene
Pressure Lb./sp. in. 500 1000 2000 3000 3000 3000 3000 500 1000 2000 2000 3000 3000 3000
Temp. Time F.
Min.
850 850 850 700 750 800 850 850 800 800 850 750 800 850
8.1 27.4 22.4 85.0 43.0 17.3 9.6 5.7 22.6 16.9 10.6
27.3 16.4 8.7
NO. of Gaso- Gaso-
Liquid Grav. of Yield Liquid line % A . P.I. % 59.1 70.0 80.8 75.0 74.8 74.3 71.4 16.3 46.9 64.0 62.8 62.6 61.0 61.2
49.0 49.3 48.0 46.5 47.5 47.7 50.1 53.2 53.6 53.4 49.8 52.7 52.5 60.3
73.8 69.5 62.5 40.2 47.3 55.0 67.1 80.3 73.1 69.5 66.2 59.5 63.4 67.1
line 78 68 64 62 63 62 63 78 87 75 80 75 74 74
Table IV summarizes the conditions for maximum polymer yield under each of the four pressures studied. I n addition, the character of the polymer produced under the optimum conditions is also shown. The yield does not increase a p preciably with increasing pressure but it was found that the capacity of the experimental unit increased over tenfold with increasing pressure. At 500 pounds pressure the maximum liquid production observed was 39 cc. per hour; a t 3000 pounds, under otherwise similar conditions, the polymer production was 450 cc, per hour. The data in Table IV seem to show that pressure, temperature, and time of contact have but little influence on the maximum yield of polymer obtainable from the two olefins. 0
Acknowledgment
TIME OF CONTACT-MINUTES
FIGURE 10. POLYMERIZATION OF ETHYLENE AND PROPYLENE AT
3000
P O U N D S PER
PRESSURE
1. Ethylene at 850' F. (454'
C.)
SQUARE
INCH
ethylene at
The authors wish to take this opportunity t o thank H. R. Batchelder, J. A. Bolt, T. A. Geissman, and C. W. Nysewander for their invaluable aid in obtaining the data forming the basis of this report.
Literature Cited 7. Ethylene at 650' F. 8. Propylene at 700' F.
(1) Dunstan, Hague, and Wheeler, J. SOC.Chem. Znd., 51, 131-3T (1932). (2) Egloff and Schaad, J. Inst. Petroleum Tech., 19,800 (1933).
SEPTEMBEH, 1935
INDUSTRIAL AND ENGINEERIXG CHEMISTRY
(3) Egloff, Schaad, and Lowry, J . Phys. Chem., 34, 1617-1740 (1930); 35, 1825-1903 (1931). (4) Ipatieff, J . Russ. Phys.-Chem. Soc., 38, 64-75 (1906); Ber., 44 2978-87 (1911); 46, 1748-55 (1913). ( 5 ) Nash, Stanley, and Bowen, J . I n s t . Petroleum Tech., 16, 830-55 (1930).
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( 6 ) Pease, J . Am. Chern. Soc., 53, 613-19 (1931). (7) Stanley, J . SOC.Chem. Ind., 49, 349-54T (1930). (8) Waterman and Tulleners, J . Inst. Petroleum Tech., 17, 506-10 (1931). RECEIVED May 24, 1935.
Polymerization, a New Source of Gasoline
FIGURE 1.
EA
KEW cata-
lytic process has been developed for the production of g a s o l i n e f r o m the olefins in cracked gas and a plant is in commercial operation which is capable of processing 3 million cubic feet of gas per day. The c o m m e r c i a l plant has operated continuously for 23 days, producing 313,090 gallons of 81-octane g a s o l i n e f r o m the olefins in 58,054,000 cubic feet of gas whose propylenebutylene content was 27.4 per cent. The y e a r l y p r o d u c t i o n of cracked gas in this country as a by-product of the cracking process is 300 billion cubic feet, of which 50 billion cubic feet, are olefins. The latter has a po-
POLYMERIZIKG I ~ P P A R A T U SOF THE U N I V E R S 4 L O I L PRODUCTS
V. S. IP.ITIEFF, B. B. CORSON, AND
GUSTAV EGLOFF
Universal Oil Products Company, Riverside, Ill. 0
A catalytic process has been developed for the conversion of gaseous olefins into gasoline. The catalyst is rugged and active and can be regenerated. Cracked gases containing 17.6, 37.5, 43.1, and 69.7 per cent of propylene and butylenes gave gasoline yields of 3.3, 6.0, 6.8, and 10.9 gallons, respectively, per thousand cubic feet of gas processed. A commercial polymerization plant is i n operation which is producing gasoline at the rate of more than 5 gallons per 1000 cubic feet of cracked gas.
COMPANY
tential production of a billion gallons of polymer gasoline of 81 octane number. The total gasoline p r o d u c t i o n i n t h i s country in 1934 (straight-run and cracked) was 17.785 billion g a l l o n s of about, 65 octane number. Mild operating conditions of 230' C. (446' F.) and 200 pounds per square inch pressure have been found satisfactory in this p o l y m e r i z a t i o n process. The catalyst is a hard, gray-towhite, granular solid, n-hioh is noncorrosive. It is not poisoned by carbon monoxide, hydrogen sulfide, mercaptans, or o t h e r constituents or refinery gases. The catalyst gradually loses its activity with continued use but can be readily regenerated t o its o r i g i n a l activity with a time
