High sulfur crude oil is desulfurized by a low temperature (25-80 C.) chlorinolysis at ambient pressure in the absence of organic solvent or diluent but in the presence of water (water/oil=0.3) followed by a water and caustic wash to remove sulfur and chlorine containing reaction products. The process described can be practiced at a well site for the recovery of desulfurized oil used to generate steam for injection into the well for enhanced oil recovery

Ernest, J. B.

Hsu, G. C.

Kalvinskas, J. J.

English

NASA Technical Reports Server

States Patent [I91 11 11 4,310,049 
[45] Jan. 12, 1982 
1541 CRUDE OIL DESUL~RIZATIBN 
[75] Inventors: John J. Kalvinskas, Pasadena; George 
e. Hsu, La Crescenta; John B. 
Ernest, Santa Ana, all of Calif. 
[73] Assignee: California Institute of Technology, 
Pasadena, Calif. 
[2l] Appl. No.: 30,831 
[22] Filed: Apr. 17, 1979 
[51] Pmt. a.3 ....................... E21B 43/28; ClOG 27/02 
[52] U.S. c1. .................................... 166/267; 166/303; 
208/241 
[58] Field of Search ..................... 166/75 R, 265, 266, 
166/267, 272, 303; 208/241, 227, 228, 230 
[561 References Cited 
U.S. PATENT DOCUMENTS 
1,263,618 4/1918 Squires ................................ 166/266 
2,107,713 2/1938 Rowland et al. ................... 208/241 
2,503,486 4/1950 Himel .............................. 208/241 X 
2,582,148 1/1952 Nelly, Jr. ............................ 166/266 
2,969,226 VI961 Huntington ..................... 166/272 X 
3,660,512 5/1972 Hamby et al. .................. 208/241 X 
3,844,349 10/1974 Snavely, Jr. et al. ............... 166/272 
3,881,550 5/1975 Barry .............................. 166/303 X 
4,007,786 2/19J7 Schlinger ........................ 166/267 X 
OTHER PUBLICATIONS 
Shreve, R. Norris, Chemical Process Industries, Third 
Edition, 1967, pp. 240-242. 
Primary Examiner-Stephen J. Novosad 
Assistant Examiner-George A. Suchfield 
Attorney, Agent, or Firm-Marvin E. Jacobs 
[571 ABSTRACT 
High sulfur crude oil is desulfurized by a low tempera- 
ture (25"-80" C.) chlorinolysis at ambient pressure in the 
absence of organic solvent or diluent but in the presence 
of water (water/oil=0.3) followed by a water and caus- 
tic wash to remove sulfur and chlorine containing reac- 
tion products. The process can be practiced at the well 
site for the recovery of desulfurized oil used to generate 
steam for injection into the well for enhanced oil recov- 
ery. 
4 Claims, 2 Drawing Figures 
https://ntrs.nasa.gov/search.jsp?R=19820015408 2020-03-21T16:28:14+00:00Z
U.S. Patent Jan. 12, 1982 4 3  10,049 
t 
CRUDE 
OIL H20 
I t  CAUSTIC 
18 
l0 
40 
t 
DESULFURIZED 
CRUDE 
t 
Fig. 1. 
Fig. 2. 
1 
4,310, 
CRUDE OIL DESULFURIZATION 
ORIGIN OF THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 83-568 
(72 Stat. 435; 42 USC 2457). 
TECHNICAL FIELD 
5 
10 
The present invention relates to desulfurization of 
high sulfur crude oils. 
BACKGROUNDART 15 
Petroleum is still the primary feed stock for oil-fired 
burners for petroleum refineries, petrochemical indus- 
tries, domestic power generation and for on-site pro- 
duction of steam for reinjection into a well for steam 
flooding which is a major Enhanced Oil Recovery 2o 
(EOR) Process being successfully practiced in Califor- 
nia and elsewhere. 
However, there are very few instances of naturally 
occurring low-sulfur crudes (less than 0.5% sulfur) and 
the limited availability makes these crude oils very ex- 25 
pensive. Combustion of high sulfur crudes leads to sul- 
fur dioxide emissions at excessive levels which require 
expensive post-combustion scrubbing of the flue gas. 
Pre-combustion desulfurization is an alternative. Sul- 
fur removal from petroleum oil at the site is much more 30 
difticult than desulfurization of coal due to the unique 
organic-sulfur form of the impurity and the EPA re- 
quirement to reduce the sulfur content to about 0.3%. 
Whereas, some coals mainly contain pyritic sulfur of the 
inorganic type which can readily be removed by physi- 35 
cal-chemical treatment, it is much more difficult to 
remove organic thiophenes from petroleum. Organic 
thiophenes are mainly liquids and tend to d i s t i l  with 
the petroleum fraction if fractionation purification is 
Hydrodesulfurization of petroleum crude oil with 
cobalt-molybdenum or nickel-molybdenum catalysts on 
an alumina support is a currently utilized desulfuriza- 
tion process. The requirements of catalysts, hydrogen 
consumption and severe reactor operating conditions 
render this process quite expensive. An urgent need for 
an economical, crude oil desulfurization process has 
been expressed by the petroleum industry in a recent 
attempted. 40 
45 
2 
049 
of the oil at ambient pressure for a short period in the 
absence of organic solvent but in the presence of a 
minor amount of water followed by aqueous and caustic 
washes to remove the sulfur and chlorine containing 
by-products. 75 to 90% of the sulfur is removed in about 
one hour of treatment. Any process equipment having a 
chlorine-resistant surface may be utilized. The only 
process requirement appears to be adequate mixing of 
the oil and chlorine gas and an efficient means of intro- 
ducing the chlorine gas. 
These and many other attendant advantages of the 
invention will become readily apparent as the invention 
becomes better understood by reference to the follow- 
ing detailed description when considered in conjunction 
with the accompanying drawings. 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 is a schematic view of a crude oil desulfuriza- 
FIG. 2 is a schematic view of a well-site desulfuriza- 
tion system in accordance with this invention; and 
tion system. 
DETAILED DESCRIPTION OF THE 
INVENTION 
The high sulfur crude oils to be treated in the process 
of the invention are petroleum crude oils containing 
from 0.5% to 3% sulfur, generally about 1% sulfur. 
Chlorinolysis is conducted at a low temperature below 
120" C., generally from 25" C. to 85" C. for at least 5 
minutes and usually for less than 120 minutes. The ratio 
of water to crude oil should be at least O.OS/l and no 
more than 0.5A. The water can be added as steam and 
separately bubbled through the crude. Chlorine gas is 
introduced at a rate of from 1 to 100 grams of Clz/lOO 
grams oil/hr. 
A brown emulsion results. The chlorinated crude is 
then treated with at least an equal volume of water at 
ambient temperature or slightly heated to a temperature 
from 20" C. to 80" C. and the water separated. The 
crude oil is then washed with at least an equal volume of 
caustic such as sodium hydroxide having a molarity of 
from 0.1 to 2. 
The carbon-sulfur (sulfide) and sulfur-sulfur (disul- 
fide) bonds of the organic sulfur components of crude 
oil are highly reactive due to high steric accessibility 
and electron releasing and demanding nature of the 
sulfur atom. Chlorine treatment in the presence of water 
brings about the scission of these bonds as follows: 
R-S-R + CI+ - C l - e R S C 1  + R'+ + CI-*RSCl + RCI 
R-S-S-R' + C1+ - CI-+RSCI + RS+ + C I ' e R S C I  + RSCI 
survey. 55 
STATEMENT OF INVENTION 
A simple, low cost method of desulfurizing high sul- 
fur petroleum crude oils has been provided in accor- 
dance with the present invention. The process has a low 60 
energy penalty, operating at very low temperature and 
ambient pressure, and can be carried out in simple appa- 
ratus with minimum capital cost for equipment at the 
drilling site and at other locations removed from the 
available refinery or process plant catalytic desulfuriza- 65 
tion installations. 
High sulfur crude oil is desulfurized in accordance 
with this invention by a low temperature chlorinolysis 
where R and R represent hydrocarbon groups. 
The resulting chlorinated organo-sulfur compounds 
are oxidized and hydrolyzed in the presence of chlorine 
and water at moderate temperature to produce sulfate 
compounds as follows: 
Most of the sulfate compounds and chlorine com- 
pounds are removed by hydrolysis during the water and 
caustic washing steps. 
3 
4,3-10,049 
Referring now to FIG. 1, the desulfurization system 
generally includes a chlorinolysis unit 10, water wash- 
ing unit 12 and caustic washing unit 14. Water and 
crude oil are fed to the chlorinolysis unit BO from lines 
16 and 18 respectively in the desired ratio, usually 0.3 
WzO/oil, by volume. The streams are at ambient or can 
be preheated to the desired temperature. Stirrer 20 is 
started and chlorine is fed to fritted glass bubbler 22 at 
the bottom of the unit. At the end of the desired reac- 
tion period, valve 24 is closed, valve 26 is opened and 
the brown emulsion is pumped through line 28 by 
means of pump 30 into unit 12. 
An excess amount of water, usually 4/1 water to oil is 
added to the emulsion through line 32 and removed 
through drain 34 and discarded after the supernatent oil 
has been transferred through line 35 into unit 14. An 
excess amount of dilute caustic, usually 4/1 caustic (1 
molar) to oil at is then added to unit 14 through line 36. 
Desulfurized crude is recovered at 40 and spent caustic 
4 
decrease. Thereafter the washed oil was further mixed 
and washed with a four-fold quantity of sodium hydrox- 
ide (1 molar). The final oil was analyzed and fraction- 
ally distilled for characterization. 
Significant desulfurization is experienced at treatment 
periods as little as 15 minutes with optimum treatment 
appearing to be at 60 minutes. EPA requirement of 
0.3% sulfur is achieved at room temperature in 60 min- 
utes, though more efficient desulfurization occurs at 50" 
10 C. The process of the invention provides low cost, 
efficient desulfurization readily adapted to the on-site 
generation of process heat or steam for EOR from oil 
wells. 
It is to be understood that only preferred embodi- 
15 ments of the invention have been described and that 
numerous substitutions, modifications and alterations 
are permissible without departing from the spirit and 
scope of the invention as defined in the following 
claims. 
5 
is discarded through drain 42. 20 We claim: 
Referring now to FIG. 2, the well-site system in- 
cludes a recovery well 50, chlorinolysis unit 52, wash- 
ing unit 54, and steam generator 55. Crude oil recovered 
from the well 50 is delivered to chlorinolysis unit 52. 
Clz is bubbled into the oil from a perforated ring bubbler 25 
56 and steam is injected into the oil from line 58. The 
chlorine treated oil is then delivered to washing unit 54 
in which it is successively washed with water and caus- 
tic from lines 60 and 62 respectively. 
combustion section of steam generator 55 along with air 
and the combustion gases generate steam in tube bank 
64. The generated steam is recycled to chlorinolysis unit 
92 and well 50 through lines 58 and 66. 
EXAMPLE 1 
A series of experiments were carried out at tempera- 
tures from 25" C. to 80" C. for periods from 0 to 120 
minutes on a crude petroleum oil containing 1 % sulfur 
obtained from the Brea-Olinda field of Union Oil Co. 40 
Chlorine was introduced at a rate of 5 grams of C12/100 
grams of oil/hour. The ratio of water to oil was 0.3. 
In typical runs, about 230 grams of petroleum was 
stirred in a glass flask fitted with a stirrer and fritted gas 
bubbler. Either at room temperature, or upon pre-heat- 45 
ing to the stated temperature, a vigorous degree of 
stirring was initiated, and chlorine then introduced to 
the lowest portion of the flask for up to one hour. A 
brown emulsion resulted. This product was washed 
with a four-fold amount of water, and the water then 50 
1. A method of reducing the sulfur content of a crude 
petroleum oil containing from 0.5 to 3% sulfur by at 
least 50% comprising the steps of: 
bubbling molecular chlorine gas through the oil in the 
presence of water at a temperature from 25" C. to 
85" C. at ambient pressure for at least 5 minutes, the 
ratio of water to oil being from 0.05A to 0.5A; 
washing the oil to remove sulfur and chlorine con- 
taining reaction products; and 
A portion of the desulfurized oil is then fed to the 30 ' recovering a desulfurized oil. 
2. A method according to claim 1 in which chlorine 
gas is bubbled through the oil at a rate of 1 to 100 grams 
of C12/100 grams oil/hour. 
3. A method according to claim 2 in which the 
35 treated oil is washed with at least an equal volume of 
water followed by washing with at least an equal vol- 
ume of caustic having a molarity from 0.1 to 2. 
4. A method of enhancing the recovery of oil from a 
well comprising the steps of: 
recovering crude petroleum oil containing sulfur 
treating the oil at the well site with molecular chlo- 
washing the oil to remove sulfur and chlorine react- 
recovering a desulfurized oil; 
feeding the recovered desulfurized oil to a boiler; 
burning the oil to produce steam; and 
injecting the steam into the well to enhance the re- 
covery of oil by steam flooding. 
from a well; 
rine gas in the presence of water; 
ing products; 
separated. The oily layer showed very little fluidity * * * * *  
55 
60 
65 


Crude oil desulfurization

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