2 94
INDUSTRIAL AND ENGINEERING CHEMISTRY 592.528
FIGURE 3 UNITED STATES CRUDE RUBBER IMPORTS.
u) z
1
/I
c? 510,000
sd u LT
IL
0
I I
I
I925
I
I
1930
1935
I
This symposium on resins and plastics from hydrocarbons is sponsored jointly by petroleum, paint and varnish, and rubber chemists. Kothing could be more fitting than for these three groups to meet together for a discussion of problems of mutual interest, representing as they do a large present and potential supplier of both raw materials and finished products, and the two largest consumers. I n my opening remarks I used the adjective “tremendous” to describe the growth of synthetic resin production during the last decade or so. That this is fully justified is illustrated in Figure 1. This curve shows the output of such products manufactured from coal tar chemicals in recent years ( 2 ) ; the production reached 141,000,000 pounds in 1937.
VOL. 32. F O . 3
The production of resins from noncoal tar chemicals is of a much lower order of magnitude, as shown (Figure 2) by a volume of 21,000,000 pounds in 1937 (2). However, in a new and coming field we are perhaps more concerned with the rate of growth than with the actual volume reached in the early stages of the development. This rate of growth is much greater in the case of the resins of noncoal tar origin. It is this capacity for growth that has its special appeal here. Turning now to rubber as the true representative of what are commonly termed “plastics”, Figure 3 shows a steady increase in imports of crude rubber to the United States, amounting to some 1,300,000,000pounds in 1937 (1). Until the problem of manufacturing rubber synthetically from domestically available raw materials has been solved, this high import of the crude product will remain a challenge to our profession. Much has been said on this subject and I need only add that a successful start has been made. We have seen, again within the last decade, several synthetics enter the field and replace rubber for specific uses where it has been possible t o effect actual improvements over nature’s product. Although highly significant both chemically and economically, the progress made so far is small when considered on a volume basis. To develop a synthetic hydrocarbon product capable of competing with natural rubber for general use on a combined basis of quality and cost is a problem that should have special appeal for those engaged in the field of hydrocarbon chemistry.
Literature Cited U.S.D e p t . Commerce, Bur. of the Census, Statistical Abstract of U. S., 1938. (2) U. S. Tariff Commission, R e p t . 131, 2nd series, 1938. (1)
PROPANE PRECIPITATION OF PETROLEUM RESINS P. T. GRAFF AND H. 0. FORREST
The M. W. Kellogg Company, 225 Broadway, New York, X. Y.
HE residuum obtained from the distillation of crude petroleum may be separated into asphalt, resin, and lubricating oil fractions by the use of the precipitating effect of liquid propane. The behavior of propane in varying ratios and a t various temperatures upon the precipitation of asphalt and resins from propane-oil solutions has been described at length in the literature (1, 6, 6). The information previously published disclosed the improvement or refining effected in the lubricating oil base by the propane precipitation of asphalt and resins. Some data concerning the characteristics of the precipitated asphalts and resins have been given. The purpose of this paper is to disclose more fully the properties of the so-called resins that may be obtained by the precipitating action of propane. The term “resins” is used widely and broadly to describe many different materials occurring naturally or produced synthetically. These range from the gums or hard resinous lacquerlike substances found in trees and plants, to synthetic substances, and to the color bodies adsorbed by decolorizing clays from petroleum fractions or other oils. This paper is confined strictly to a consideration of propane-precipitated petroleum resins.
Propane-precipitated petroleum resins contain those hydrocarbons or color bodies which are adsorbed on clays or earths in the treatment and refining of petroleum lubricating oils and which may be dissolved or washed from the clay by solvents such as benzene. These hydrocarbon substances are similar to asphaltenes except that they are not oxidized or combined with sulfur and are therefore soluble in petroleum ether. In addition to containing hydrocarbons conforming to the usual definition of petroleum resins, propaneprecipitated petroleum resins contain paraffinic and naphthenic hydrocarbons of high molecular weight and also asphaltenes, in quantities or proportions depending upon the precipitating conditions and the previous treatment of the oil. Propane fractionating technique provides a comparatively simple process method of producing a “resin” fraction from petroleum and this fraction may represent a portion of the crude petroleum not readily isolated by other industrial process methods available to refiners.
T
Examples of Resin Precipitation The essential operations of precipitating resins by the use of liquid propane are indicated in Figure 1, which shows the
INDUSTRIAL AND ENGINEERING CHEMISTRY
MARCH, 1940
CHARGE
INSPECTIONS
aRAVlTY lS.2*A.Pl. FLASH. c 0 . c . 575.E PIRE, 5 . 0 C. 655.F.
VISCOSITY
306 S.S
[email protected]. 7.4 WT U 1.155
GARB. R E I . v . 0 0.
-
I
m W
-
QR4VlTY VI5COIITY COLOR
T n
3 1 D T. R. COLOR C I R B . RES. '2.50 WT. V. Q.C. 0.833
Z2.I04.P.I. 199 S,S,U,@ZlO'K 0-1.R.
%
I4 0-F.
I
1 *
RESINS
ASPHALT YIEW 10 9 % 8R 811. LO157
VELD CRAVIYY VIS.
I~D-F.
CUI. 11.F. 4 DY51ILITY 0 G O % , SOL. 99.llK CI SOL. 99.71% llAP?HTW-IOL. '8.34; llAPHlM-IWWL. 13.7 % T ~ R 12.7 % NOH-TARRV Mn.R€I. O M IN OR^. ma. 0.38 %
x
S W E R
{
~ 4 ~ RES. 0 . z.ea V.4.C. 0.831
IO5'F.
MELT. PT.
295
GARB. REI. V.0.C.
CCI.
cs
*%
11.9
aoL. SOL.
14.8 '1. P.1. 1000 a,
[email protected]*. 11.1 U T . % 0.078 99.15% e9.16%
d w n w s o L . aai79c
ncsnm-
msoL. 0.- tc T U 0.15% NOH -TARRY O W K S . 0 . 0 8 S Z
%
*
DEPROPANIZED
PRODUCT
FIGURE 1. PROCESS DIAGRAM FOR PROPANE DEASPHALTING AND DERESINING OF MID-CONTINENT CRUDERESIDUVM
proportions of propane used, settling temperatures, and products realized in two-stage operations on mid-continent crude residuum. The first stage is used for the separation of asphalt, and the second stage accomplishes the propane pre-
Propane precipitation provides a relatively new process for the separation of petroleum resins from crude residua and heavy distillates. Because of the high molecular weight and high boiling point of these resins, it has been difficult heretofore to separate these components of petroleum on an industrial scale. The separation in propane is conducted a t moderate temperatures, and therefore no injury results to the natural properties of the resin components of the crude oil. Color bodies, carbonforming material, and some asphaltenes are found in the products. In addition, high-viscosity oil fractions are settled out with the resin material, the oil consisting of high-molecular-weight naphthenes and paraffins. The quantity and, to some extent, the nature of the oil so included may be controlled by the temperature and propane solution ratio, and thus a means is available of making narrow cuts of highviscosity products. One or more additional stages of settling in propane solution will further subdivide the product into oils and a resinous residue.
cipitation of a resin fraction leaving an improved and partially refined lubricating oil base stock dissolved in the propane. The asphalt product is high in melting point, hard, and brittle, and contains most of the asphaltenes or material insoluble in petroleum ether. The properties of the deasphalted residuum after depropanizing are indicated. In the steps of propane precipitation illustrated here, the deasphalted oil while still in propane solution is further diluted with an additional quantity of propane (200 volume per cent of the original residuum), and a heavy oil fraction called "resins" is precipitated in the resin settler a t 140' F. ( S O o (3.). The inspections of the original residuum and depropanized products show that the heaviest hydrocarbons and asphaltenes are DERESINING OF SANTA FE SPRINGS CRUDE FIGURE 2. PROPANE VACUUM-STILL DISTILLATE DISTILLATI
Gravity Viscosity Carb. res. V. G. C.
15.7' A. P. I. 400 €3. €3. U. a t 210' F. 4 . 3 wt. 70 0.880
I
$
Primary Precipitation Propane 10 vol. Temperature 100' F.
4
5.
PRIMARY R E S I N 0
D E R E S I N E D OIL
Yield, Grantyl Viscosity Carb. res. V. G. C.
82 vol. 5% 18.3' A. P. I. 220 S. S. U. a t 210' F. 2.39
Yield
18 vol. %
?&pat 7 7 ' 1
6
145* F.
0.867
Resin +Vsahing Propane 3 vol. Temperature 100' F.
.+
J.
WASHBD R E S I N 5
WASH OIL
Yield, Gravlty Viscosity V. G. C.
5 vol. %
16.8' A. P. I. 350 9. S. U. at 210" F. 0.872
Yield Sp. gr.
M.P.
Pen. at 77' F. Mol. wt. Unaulfonated residue
13 vol. 5% 1.045 170' F. 1
590
Approx. 10%
INDUSTRIAL AND ENGINEERING CHEMISTRY
296
RESIS SETTLERSIN
A
VOL. 32, NO. 3
COMMERCIAL PROPANE DEWAXING AND DERESINING PLANT
concentrated in the asphalt, that the precipitated resins are of higher specific gravity than the charge while the hydrogencarbon ratio is lower, and that paraffinicity of the resins as measured by the viscosity-gravity constant (1'.G. C.) value ( 3 ) is less than for the deasphalted and deresined oil. The improvements in color and in carbon residue of the deresined deasphalted oil show the concentration of color bodies and carbon-forming material in the propane-precipitated resins. According to the usual definition of petroleum resins, that they are materials adsorbed by clay, the nomenclature of resins is not incorrect for material precipitated from petroleum fractions in propane solution a t temperatures above 130-140' F. (54.4-60" C.). The references cited showed that, as the temperature is increased to the critical tempera-
ture of propane (212.2' F. or 100.11" C.), less of the viscous oil is found in the propane solution and therefore with increasing temperature the character of the resin fraction may more closely approach that of the oil charged to the resin settler. Propane precipitation effects some refining with respect to increasing paraffinicity as indicated above and in Figure 2, which shows the effect of the propane precipitation of a resin fraction with propane washing thereof for a vacuum still distillate from Santa Fe Springs crude. In this case the precipitate contains mostly entrained asphalt. However, under deresining conditions the lesser quantities of propaneprecipitated materials approach in character the type of resin removed from petroleum fractions by clay filtration.
FIQURE 3. PROCESSING OF A TEXAS CRUDERESIDUUM TEXAB CRUDE RESIDUUM
Gravity Viscosity Carb. res. Color, OD V. G. C.
17.3' A. P. I. 409 S. S. U. at 210° F. 6.74% 21,565 0.866
NITROBENZENE EXTRACTION*
PROPANE DEABPHALTINQ
Propane Temperature
980 vol. % 100' F.
I
Yield Sp. gr. M. P.
1 3 . 2 vol. % 1.057 180" F.
.1
I
4,
J.
Yield. Gravity Viscosity Carb. res. Color, O D
RAFFINATE
EXTRACT
DEASPHALTED OIL
ASPHALT
8 6 . 8 vol.F% 19.6' A,:?. I 229 9. S.V. a't'210' F. 2.95% 1552
Yield
58 vol. %
Yield, 42 vol. % Gravltv 25.1' A. P. I. Viscosi'ty 179.5 S.S. U. at 210' F. Carb. res. 1 . 8 4 % Color, O D 9147
PROPANE DERESININQ
NITROBENZENE EXTRACTION*
EXTRACT
* By Atlantic Refining Company.
Propane Temperature
RAFFINATE
RESINS
970 vol. yo 150' F.
DERESINED OIL
297
INDUSTRIAL AND ENGINEERING CHEMISTRY
MARCH, 1940
RESINS
ASPHALT 18 VOL.%
SP OR
4 V0L.K ORbVlTY B ' A P.1 VIS. 1000s.9 u.@ Z I O ° F
1.08
MELT PT. Z O O O F
DEASPHALTING AND DERESINING FIGURE4. REFINERY
carbon concentration appears to come in the material settling out of propane solution.
Propane Selectivity in Precipitating Color Bodies A comparison of the effect of propane precipitation and of selective solvent extraction is shown in the diagram of the processing of a Texas crude residuum (Figure 3). I n one case the residuum was propane-deasphalted and then nitrobenzene-extracted; in the other case propane was used to precipitate a low A. P. I. gravity resin fraction from the raffinate produced by nitrobenzene extraction of the crude residuum. A comparison of the original charge and the intermediate and final products with respect to carbon residue and color (optical density values, 2 ) shows that propane precipitation of asphalts and resins is highly effective in concentrating the carbon-forming and color material in the precipitates. The selective solvent improves the paraffinicity, V. G. C., and carbon residue. Per unit volume removed in propane precipitation or in solvent extraction, the greater
Commercial Resin Precipitation Propane precipitation of petroleum resins is used commercially to reduce the duty of clay in decolorizing lubricating oil stocks. Figure 4 shows the operation of a refinery unit which both deasphalts and deresins a selected mid-continent crude residuum before solvent extraction, dewaxing, and finishing. Inspection of the resins as well as of other products is given. Propane-precipitated petroleum resins may vary greatly in composition, depending upon the nature of the residuum and its previous treatment and upon the conditions of propane dilution and temperature of settling. These resins may be narrow cuts on the crude and consist predominately of
-CHARGE-
PROPbNE
197' A P I GRAVITY IO05 ssu VIS 210'E IDD COLOR-TR 635 FLASH. C.0.C. "F 730 FIRE C O C O F 841 V. G C.
RESINS 1830%
h
I
CYCLE SOLUTION TO
v PRIMARY RESVV S E T T L E R
I62 9 SSU VIS. 2 W F
I D COLOR-T.R
I I
2DCOLOR.IR i 3 8 CAR RES % ,617 V G C
1
,828 V G . C
5-1/2 D COLOR-TR 2 32 CAR RES % ,826 YGC
,
1
I
I TEMP 180eF.
, T E M P 120-F
\'" .1
WASHED RESINS* 4 4 VOL % OF CYLDR ST ( 5 6 ' &PPI G R A V I T I
+
I97O A E
GRAVITY 1243 S S U VIS. 210'F 3-1/200 COLOR-TI1 6 4 CAR RES %
.a33 yoc DEPROmNIZED
*
HIGH-VIS, srom VOL % O F CYLOR ST
l S
I
LOW-VIS STOCK* 46 OF CYLDR GRAVVITY 521 SSU VIS. 2lO0F 30 C O L O R - T R . 3 7 CAR. R E S . % 8 2 5 VG.C 4 3 VOL 221D API
ST
OIL
FRACTIONATING RESINSFROM DEWAXED PENNSYLVANIA CYLINDER STOCK FIGURE 5. PROPANE
INDUSTRIAL AND ENGINEERING CHEMISTRY
298
color bodies and hydrocarbons with high carbon-to-hydrogen ratios. When broader cuts are produced, the resin fraction may have associated with it lubricating fractions of high molecular weight. Inspections were published (4) of two different propane resin products obtained in a refinery from dewaxed Bradford, Penna., cylinder stocks, which are repeated here : Resins of cylinder stock 3.5 Resins: of Bradford crude 0.63 Propane used, vol. yo of dewaxed cylinder stock 1,100 Temperature of settler, F. ( " C.) 154(67.8) Ins ection ranty ', O A. P. I. 16.1 Viscosity, S. S. U. (seconds, Saybolt Universal) at 210' F. (98.93 C.) 3,860 Color optical density 28,960 Garb& residue, wt. % 12.6 635(335) Flash (Cleveland open cup), ' F. ( " C . )
B
13.0 2.34 1,100 171(77.2)
:
19.4
High-Viscosity Stook Cut fraction, vol. % of high flash cyl. stock Overhead cut fraction on Bradford crude, vol. yo Ins ection: Zravity O A P. I Viscositj, s.'s. U:at 2100 F. (93.3 C.) Carbon residue, wt. % V. G.C.
Washed Resins
2.1
2.4
99.1-99.5
99.5-100.0
18.5
15.5
1795 9.4 0.837
4073 13.5 0.852
PHBNOL S O L V ~ W TEXTN. Ra5nate Ext. Raffinate 59.2 Yield, vol. % 65.4 34.6 Ins ection: 21.4 23.3 10.2 Zravity 0 A. P. I. Vimositj s 8.U.a t 2100 F 2180 1312 (93.3 'c.j ' Visoositu. 8. 8. U. at 150' F 13030 6930 2 ' / L D D ... 5'14 D D D Co\::";:kobinson 3.3 5.6 Carbin residue. wt. % 0.802 . . . 0.810
Nontsr organic Inorganic residue
...
..
..
...
..
40.8 1 .Ol64(sp. gr.) I . .
... ... ... li6(i2.2) 22 l08+ 99.46 99.89 9s.99 1.01 0.934 0.064 0.012
... ... ...
The residual cvlinder stock from which the hieh-viscositv stock and the washed resins were precipitated was first propane-dewaxed; therefore it is probable that some of the color materials or resins were precipitated with the wax. The petrolatum is dark (higher than 10,000 OD) and is believed to contain resins amounting to about one per cent of the cylinder stock. The inspection indicates that this Pennsylvania crude has approximately 0.2 per cent of material resembling asphalt, except for the low percentage of asphaltenes, and that with it are associated high-viscosity paraffin hydrocarbons. This latter material is probably very stable because of its paraffinicity and high molecular weight. The two propaneY
Original resins Oxidized resins Oxidized resins Oxidized resins Oxidized resins
Ball and Ring Softening Point (A. S. T. M.D36-26) F. (" C.) Below SO(26.7) 107 41 7) 115146: 1) 131(55) 218(103.3)
Penetration 100 G . Total Wt. (A. S. T. M. D5-25) Cm. x 10-1 Too soft 142 101 59 23
Soluble in CClr
% 99.96 99.96 99.96 99.96 99.20
This oxidation reduces the susceptibility of the penetration t o temperature changes, as shown in the following comparison of the penetration of the original propane-precipitated resin and that of the final oxidized product with a 219" F. (103.9' C.) ball-and-ring softening point: Temp.,
F.(O C . )
Penetration (A. S. T. M. D5-25), Cm. X 10-2 Original resins Final oxidized resins (100 g. total wt.) (200 g. total wt.) 19 21 24 26 32 39 42 61
Users of plastic substances produced from petroleum will observe that it is possible by oxidizing the propane-precipitated resins to obtain plastic material with excellent temperature-penetration susceptibility characteristics and to have a t the same time materials which are very stable.
Ext.
... ... ...
...
precipitated fractions represent regular refinery production, and their phenol extraction is feasible on a plant scale. The production of propane-precipitated resins has commercial significance, since the product from Pennsylvania crude is marketed and its ductility characteristics recommend its use in the manufacture of insulating and waterproofing materials. These resins are reported t o have an unusually high degree of resistance to acids. Propane-precipitated resins from Pennsylvania cylinder stock were oxidized in batch stills, and the effecton the softening point and penetration is shown in the tabulation of properties of the oxidized products; the oxidized oils are almost completely soluble in carbon tetrachloride :
1,161 12,650 7.9 635(335)
The 13 per cent resins from the dewaxed Bradford cylinder stock may be fractionated in propane solution into highviscosity oil cuts by settling successively a t increasing temperatures. Such an operation is similar to that shown in Figure 5. The major portion of the wax-free 13 per cent resins is excellent quality oil of high viscosity. These highviscosity oil fractions find special uses, and since the separation takes place a t a maximum temperature of 180" F. (82.2' C.), there is no degradation of the natural lubricating qualities of the oils. The characteristics of propane-precipitated resin fractions from Bradford dewaxed cylinder stock are also apparent from the results of phenol countercurrent tower extraction of two of the plant products:
VOL. 32, NO. 3
Acknowledgment The authors wish to acknowledge the privilege of repeating here data furnished by the Atlantic Refining Company, by the Union Oil Company of California, and by Mr. W. B. McCluer of the Kendall Refining Company. Literature Cited (1) Bray, Swift, and Carr, Proc. Am. Petroleum Inat., 111, 14, 96 (1933). (2) Ferris and McIlvain, I N D .E N G .C H E M .Anal. , E d . , 6, 23 (1934). (3) Hill and Coats, I N D .E N Q .C H E M .20, , 642 (1928). (4) McCluer, Dickinson, and Forrest, Oil Gas J., 37, No. 27, 209 (1938). (5) Wilson and Keith, Proc. Am. Petroleum Inst., 111, 15, 106 (1934). (6) Wilson, Keith, and Haylett, IND. E N G .C H E M .28, , 1065 (1936).
