INDUSTRIAL AND ENGINEERING CHEMISTRY
750
Grummitt, Oliver, Sensel, E. E., Smit,h, W. R., Burk, R. E., and Lankelma, H. P., I b i d . , 67, 910 (1945). (18) Hepp, H. J. (to Phillips Petroleum Co.), U. S. Patent 2,461,545 (17)
(1949). (19)
Hoskins, V. M., and Ferris, C. A , , IND. ERG.C H E M . ,AKAL.ED., 8, 6 (1936).
Hughes, E. C., et al., Division of Chemistry, 117th Meeting, -kx. CHEM.Soc., Houston, March 1950. (21) Ipatieff, V. N., and Grosse, A. V.,IND.EXG. C H E M . ,28, 461
(20)
(1936). (22)
Xomarewsky, V. I., and Click, S. C . , J . Am. Chem. Soc., 69, 492 (1947).
Lien, A. P., and Evering, B. L. [to Standard Oil Co. (Indiana)], U . 8. Patent 2,427,865 (1947). (24) McCauley, D. 9., Shoemaker, B. H., and Lien, A . P., Division of Petroleum Chemistry, 117th Meeting, AM. CHEY. Soc., Houston, March 1950. (25) Montgomery, C. W., Mcrlteer, J. H., and Franke, N. W., J.
(23)
Am. Chem. SOC.,59, 1768 (1937).
EngFnyring
(26)
Oblad,
Vol. 43, No. 3
G., and Gorin, M. H., IND.ENG.C H E X . , 38, 822
(1946).
( 2 7 ) Pines, Herman, and Wackher, R. C., J . Am. Chem. Soc., 6 8 , 595 (1946). (29)
W.J., I N D . E N G . C H E M . ,ASAL. E D . , 5, 172 (1933). Powell, T. M., and Reid, E. B., J . Am. Ckem. Soc., 67, 1020
(30)
Richmond, J. L. (to Phillips Petroleum C o . ) . U. S . Patent
( 2 8 ) Podbielniak, (1945).
2,461,568 (1949).
Stewart, T. D., and Calkins, W. H., Division of Physical and Inorganic Chemistry, 115th Meeting, AM. C H E M . SOC., San Francisco, March 1949. (32) Thomas. C. A , , "Anhydrous Aluminum Chloride in Organic Chemistry," Am. Chem. Soc. Monograph No. 87, S e w York. Reinhold Publishing Corp., 1941. (33) Whitmore, F. C., Chen,. Eng. ,Vews, 26, 668-74 (1948). (34) Wilcox, L. V., IND. E X G . C H E M . ,ASAL.ED.,4, 38 (1932). (31)
RECEIVED hIay 15, 1950.
Presented before the Division of Petroleum Chemistry a t the 117th Meeting of the A M E R I C A NC H E M I C A L SOCISTI-, Houston, Tex.
Separation of Sulfur and Aromatics from Petroleum
process development
WITH BORON FLUORIDE A N D HYDROGEN FLUORIDE I
E. C. HUGHES, W. E. SCOVILL, C. H. WHITACRE, R. B. FARIS, J. D. BARTLESON, THE STANDARD OIL CO.
AND
S. M. DARLING
(OHIO),CLEVELAND, OHIO
T h e high-sulfur crudes produced in this country have less value than the sweet crude oils. The sulfur compounds are troublesome to refine, requiring special noncorrosible equipment. The presence of the sulfur in products is undesirable in every case. The work was undertaken in an effort to provide basic information on a novel method of separating sulfur compounds. I t was shown that the majority of sulfur compounds in crude oil and even in the heaviest 50% of the crude oil can be removed by the new combination of reagents, and that it is also possible to separate the aromatics. The significance of these results is twofold. The funda-
mental science shows that the system hydrogen fluorideboron trifluoride will form complexes with aromatics and sulfur compounds in the same way as Friedel-Crafts catalysts, and that it is possible to disassociate these complexes at higher temperatures with recovery of the reagents. Practically it would be possible to use these reagents for large scale separations of sulfur or aromatic compounds. The process is in competition with solvent extraction processes. The reagent is highly selective and easily recoverable. Preparations of high quality lcerosenes, lubricating oils, and crude oils from stocks of poor quality are suggested as possible uses for the reagent.
F
vessels which could be weighed to measure the charges. The desired partial pressure of boron fluoride was maintained from a small cylinder, which also could be weighed t,o measure boron fluoride consumption. The react'or was immersed in a water bath. The contents of the reactor were removed through a long siphon tube. The solvent and hydrocarbon phases were usually collected in separate pressure vessels in which they could be weighed. Use of an external connection of flexible saran tubing made it possible t o detect the interface between the dark solvent phase and the hydrocarbon phase as the reactor was emptied. The solvent phase was neutralized in iced sodium hydroxide solution and released hydrocarbon was recovered. The hydrocarbon phase was neubralized prior t o analysis. Standard (1, 3 ) test procedures Rere employed in determining the sulfur and aromatic content of the oils. Fluorine was detcrmined by a method described by Hoskins and Ferris (6). Prior t o titration of the fluorine, however, the oil samples were oxidized in a bomb as outlined in the procedure for dekrmination of sulfur in petroleum products ( 1 ) . Cracking of the hydrocarbon was avoided by controlling temperature and quant'ity of the reagents; polymerization, by using nonolefinic stocks. The only variable investigated was the effect of relative quantities of hydrogen fluoride. As the original plan was t o use a n excess of hydrogen fluoride, hydrogen fluoride volumes from 0.5 t,o 1 part of the hydrocarbon volume were first employed. It was observed that the formation of a n interface layer could be avoided and the experimental work simplified by reducing this volume t'o 10% or less of the hydrocarbon volume,
OR some time aluminum halides with the halide acid have been known to form complexes with aromatics ( l a , 13, 15) a,nd aromatics have been separated commercially from lubricating oil fractions with these reagents ( 8 , l l ) . Recently hydrogen fluo-. ride has been described as a reagent for removing sulfur compounds (5, 9, 14). Boron fluoride has been used with hydrogen fluoride for treating purposes ( 3 , 4). The results of treating a number of stocks with hydrogen fluoride and boron fluoride are given in this paper. Aromatics and sulfur-containing compounds were substantially removed by the solvent system. APPARATUS AND PROCEDURE
The apparat'us and procedures employed are described by Hughes and Darling ( 7 ) . The boron fluoride and hydrogen fluoride were obtained in cylinders from the Harshaw Chemical Co. and were used as reeeived. Under t,he conditions used in this work, the solvent system consisted of a liquid hydrogen fluoride phase and a gaseous boron fluoride phase. The apparatus employed was a >Ionel-lined pressure bomb with a 3-inch inside diameter and a capacity of 2 . 8 liters. The bomb was equipped with three turbinelike stirrers which rot,ated inside a peripheral group of stationary hlonel baffles. Before each experiment the apparatus was thoroughly dried and flushed with t,ank nitrogen. The hydrogen fluoride and hydrocarbon charges were forced into the reactor from pressure
March 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
O F LIGHTGAS OIL TABLE I. TREATMENT
FROhI A
ExDeriment No.
2
751
MISSISSIPPI
CRUDE
1
Operating Conditions Temperature, F. Contact time, min. System pressure, Ib./ss. inch
Untreated Stock
Reagent composition based on hydrocarbon H F , vol. 70 BFaa, wt. 7 0 Properties Gravity, A.P.I. a t 60' F. Aromatics, vol. % Sulfur, wt. 7'
r)
Distillation data Initial b.p., F. 00% b.p., O F. Final b.p., F. Distillate, % Raffinate, wt. %
424 506 580
90
Properties Aromatics in Engler distillate, vol. % Sulfur, wt. 7 '
*
80 30
82 30
90 30
8
150
30
60
51
0 21
51
98.5 18.8
41.0 18 0.116
39.5 17
44.2
405 511 635 98 94.7
352 511 620 98 82.2
404 513 636 98 95.6 28
19.4
6
.,.
.
,
0.071
O
-
0
g80
44.9 4 0.063 179 506 580 90 74.1
Extract 71
.
CONDITIONS: BF, PRESSURE= l5Op.s.i,(PARTIAL)
84
TEMP."F: = 90'
Distillation d a t a Initial b.p., O F. 50'% b.p., F. Final b.p., O F. Distillate, % Extract, wt. % a
4
80 30
0
39.7 18 0,206
3 Raffinate
420 517 586 87 3.7
.. . ... ,.,
CONTACT TIME = 15 MIN.
370
348
...
630" ... 97 1.5 17.8
620 90 21.3
Includes BFI in vapor phase of autoclave.
so smaller amounts of the reagent were used in subsequent experiments.
J
0
TREATMENT OF DISTILLATES AND C R U D E O I L S
The results obtained by treating a variety of stocks with hydrogen fluoride-boron fluoride are shown in Tables I and 11. Experiments using hydrogen fluoride and boron fluoride separately showed that partial desulfurization was effected with hydrogen fluoride alone, but aromatic removal was not marked. Substantial improvement in desulfurization was observed through the use of hydrogen fluoride with boron fluoride. The major difference, however, was the removal of most of the aromatic portions from all the fractions. The hydrocarbon recovered
Figure 1.
I IO VOLUME
Treatment of Kerosene with Hydrogen Fluoride and Boron Fluoride
from the "extract" complex was found t o contain 71 to 97% aromatic compounds. The selectivity of the process for aromatics is thus shown t o be high. All of the aromatics were not removed, as shown by residual values of 2 to 6%. This reflected other observations t h a t benzene or toluene in heptane was only partially
TABLE11. TREATMENT OF SEVERALDISTILLATESFROM 5
Experiment No.
Heavy Naphtha Untreated stock Raffinate
49 12.2
Properties Aromatics in Engler distillate, vol. Yo Sulfur, wt. 9% Distillation deta
0
b
Includes BFs in vapor phase of autoclave. Cylinder stock raffinate dewaxed.
54.0 13 0,053
55.9 2
... ... ...
AN
ILLINOIS CRUDE
6 300 Neutral Oil (Dewaxed) Untreated stock Raffinate
-4 30 20
Propertiesb Gravity A.P.I. at 60' F. Aromatics, vol. % Viscosity-gravity constant Viscosity index Sulfur wt. % Raffinkte, wt. %
I I I I 20 30 40 50 PERCENT HYDROGEN FLUORIDE
7 Cylinder Stock Untreated stock Raffinate
110
150
15 198
380
30
99.2 21.7 24.3 ..,
0.853 58.7 0.46
85.5
30.5
0:Sls
94.2
0.10
56.3
10 8.1 19.2
6:857
...
0.68
27.1 0.800
93.7 0.12 43.8
Extract 97 296 347 423 85
1.85
33.1 7.9
55.3
INDUSTRIAL AND ENGINEERING CHEMISTRY
152
TABLE 111. EFFECT OB VOLUMEOF HYDROGEN FLUORIDE ON REFININGOF KEROSENE" Operating conditions. BFs pressure. 150 Ib./sq. inch (partial). Contact time 15 minntes. Ternperatire 90' F. Properties of Raffinate HF, Gravity Expt. Vol. Raffinate, BFs, Extract, A.P.I. bromatics, No. yo Wt. Wt. yo Wt. 7, a t 60' F. Vol. Yo 8 5.65 89.0 8.7 4.5 45.1 8 9 10 88.0 9.9 10.3 46.0 4 10 10 86.2 9.3 8.2 45.4 5 11 15.6 86.9 12.3 11.5 46.4 4 12 15.2 87.7 11.2 11.2 46.4 2 13 20 82.2 15.3 18.2 46.2 7 14 30.5 83.6 14.9 13.1 47.8 1 16 28.8 84.8 14.9 13.3 47.2 1.5 16 40 78.8 17.5 13.0 47.5 3 Charge stock 43.3 16 a From Illinois crude having boiling range of 361' to 507' F. a n d 0.042y0 sulfur. Sulfur content of this kerosene was reduced to 0.01.54R in experiment 11.
separated by the reagents under these conditions. It, therefore, appears t h a t some aromatics do not form as strong complexes as others (IO). The selectivity was equally good for naphthas and for the heaviest lubricating oil fractions. The production of 90 t o 95 viscosity index oil from Illinois crude lubricating fractions suggests the possible utilization of the process in place of solvent extraction. B complex of reagent with aromatics which was insoluble in both phases formed a t the interface. This complex formation led to the study of the effect of hydrogen fluoride volume shown in Table 111. Hydrogen fluoride volumes of 10 t o 28% of the hydrocarbon phase were found t o be ample for removing aromatics from kerosene (Figure 1). CRUDEOILS.Results of the treatment of some higher sulfur crudes are shown in Tables IV, V, and VI. These crudes are termed "reduced" crudes because the gasoline boiling to 250" F. had been removed before they were treated. With the use of hydrogen fluoride alone, the sulfur removed wad rather meager, but a very good reduction, from 0.85 t o 0.11% (experiment 18), was obtained when the combination reagent was used. However, with the use of about half as much boron fluoride (experiment 19), the concentration of sulfur was reduced from 0.87 to only 0.32% Thus the amount of sulfur compounds removed can be
T.&BLE
1'.
20 Untreated Stock
Operating conditions Temperature, F. Contact time min. System presske, lb./sq. inch Reagent composition based o n hydrocarbon HF, vol. % BFa, wt. % PropertiesQ Gravity, A.P.1. at 60' F. Aromatics i n Engler distillate, vel. ,% Viscosity-gravity constant Viscosity a t 100' F., S.U.S. Sulfur, wt. % Fluorine, wt. yo Raffinate, wt. %
""I.
TREATYEKT OF Experiment No.
YAZOO CRUDEREDCCED TO 225" F. 17
18
Untreated Stocka
RaffiRaffinate nate Operating conditions Temperature, F . 110 110 Contact time, mln. 13 15 System pressure. ib./ sq. inch 33 60 Reagent comDosition -based onhydrocarbon H F , vol. % 100.2 100.7 BFs, wt. % 0 14.0 Properties Gravity, h.P.1. a t 60° F. 29 9 30.7 37.5 Aromatics in Engler distillate, voi. % 54 38 31 Viscosity-gravity oonstant. 0.836 0.826 0.797 Viscosity a t looo F., S.U.S. 87.1 65.6 Sulfur, wt. yo 0.85 0.65 0.11 Distillation data Initial b.p., F. 295 360 313 50% b.p., ",F. 643 650 629 Final b.p., F. TO4 687 667 Distillate, 7G 95 92 96 Raffinate, rvt. yo 91.2 55.2 Interface, wt. Yo
19
Un-
treated Stock
RafEnste 110 15
50
96.5 8.7 30.2
33.2
36
28
0.836 82.7
0.886
290 615 675 93
Distillation data Initial b.p., F. 466 252 507, b.p., F. Final b.p., F. 590 619 Distillate, ?& 63 42 Extract, wt. 10.1 34.7 Interface, wt. % a 7.157, distillate removed. b Extract of experiment 19 heated to 350" F.
0.818 78.3 0.32 340 664 6Q4 90 69.2 4.7
322 713 726 74 15.4 10.8
controlled hy thc quantity of boron fluoride provided. Reduced West Tevas crude containing 2.26% sulfur was separated into a 55.7% raffinate having only 0.30y0sulfur. A comparison of the distribution of the products of the crude and the raffinate (Table VII) shows several major differences between thc crude oil and the raffinate. The aromatic content of the distilled fractions was very much lower for the rafinate. In particular, the material boiling above 1000 F. (atmospheric
TREATMENT O F WIGST TEXAS CRUDE REDUCED TO 250' F.
Experiment No.
Propertiesb Aromatics
TABLE ITT.
Vol. 43, No. 3
Raffinate
21 (Vapor Phase) Raffinate
100 60 Stmospheric
100 15 165 10 8.8
3.5 11.2
25.7
37.8
35.0
0 .'866 77.2 2.26
0:817 43.6 0.30 0.058 55.7
Q:g27
...
0.55 0.06 62.9
Extract in
Engler
distillate,
al,
5.76 SUI
