U.S. patent application number 12/570042 was filed with the patent office on 2011-03-31 for method for desulfurization of hydrocarbon oils.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Deborah Ann Haitko, John Aibangbee Osaheni, Grigorii Lev Soloveichik.
Application Number | 20110073526 12/570042 |
Document ID | / |
Family ID | 43242871 |
Filed Date | 2011-03-31 |
United States Patent
Application |
20110073526 |
Kind Code |
A1 |
Haitko; Deborah Ann ; et
al. |
March 31, 2011 |
Method for Desulfurization of Hydrocarbon Oils
Abstract
Provided herein are processes for desulfurization of a
hydrocarbon oil. The processes comprise providing a hydrocarbon oil
comprising sulfur impurities and mixing the oil with a phase
transfer agent and a source of hypochlorite ions to provide a
mixture. The mixture separates into an aqueous hypochlorite phase
and a non-polar oil phase. The hypochlorite phase may then be
removed from the oil phase, and the oil phase centrifuged and
separated from any precipitate, thereby providing a cleaned oil
phase.
Inventors: |
Haitko; Deborah Ann;
(Schenectady, NY) ; Osaheni; John Aibangbee;
(Clifton Park, NY) ; Soloveichik; Grigorii Lev;
(Latham, NY) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
43242871 |
Appl. No.: |
12/570042 |
Filed: |
September 30, 2009 |
Current U.S.
Class: |
208/236 ;
208/208R |
Current CPC
Class: |
C10G 2300/1037 20130101;
C10G 21/27 20130101; C10G 2300/202 20130101; C10G 21/08 20130101;
C10G 2300/1074 20130101; C10G 2300/44 20130101; C10G 3/00 20130101;
Y02P 30/20 20151101; C10G 21/06 20130101 |
Class at
Publication: |
208/236 ;
208/208.R |
International
Class: |
C10G 17/00 20060101
C10G017/00 |
Claims
1. A process for desulfurizing a hydrocarbon oil comprising:
Providing a hydrocarbon oil comprising sulfur impurities, mixing
the hydrocarbon oil with a phase transfer agent and a hypochlorite
ion source to provide a mixture, and allowing the mixture to
separate into an aqueous hypochlorite phase and a non-polar oil
phase.
2. The process of claim 1, further comprising agitating the mixture
prior to allowing the mixture to separate.
3. The process of claim 1, wherein the phase transfer agent
comprises one or more cationic, anionic and nonionic
surfactants.
4. The process of claim 3, wherein the phase transfer agent
comprises one or more quaternary ammonium salts, quaternary
phosphonium salts and crown ethers.
5. The process of claim 4, wherein the phase transfer agent
comprises one or more of tetrabutyl ammonium bromide, tetrabutyl
ammonium hydrogen sulfate, tributylmethyl ammonium chloride,
benzyltrimethyl ammonium chloride, benzyltriethyl ammonium
chloride, methyltricaprylyl ammonium chloride, dodecyltrimethyl
ammonium bromide, tetraoctyl ammonium bromide, cetyltrimethyl
ammonium chloride, cetyltrimethylammonium bromide and
trimethyloctadecyl ammonium hydroxide.
6. The process of claim 5, wherein the phrase transfer agent
comprises cetyltrimethylammonium bromide (CETAB),
tetrabutylammonium bromide (TBAB) or a combination of these.
7. The process of claim 1, wherein the phase transfer agent is
provided in an amount of from about 0.01 wt % to about 1 wt % based
upon the weight of the hypochlorite ion source.
8. The process of claim 1, wherein the phase transfer agent is
provided in solution.
9. The process of claim 8, wherein the phase transfer agent is
provided in solution with water, in a concentration of from about
0.05 wt % to about 0.5 wt %.
10. The process of claim 1, wherein the hypochlorite ion source
comprises sodium hypochlorite, calcium hypochlorite, or a
combination of these.
11. The process of claim 1, further comprising separating the
phases.
12. The process of claim 11, wherein the hydrocarbon oil and/or
hypochlorite ion source is/are recycled to the process.
13. The process of claim 11, wherein the hydrocarbon oil and/or
hypochlorite ion source is/are recycled to a different
process/point of use.
14. The process of claim 11, further comprising subjecting the
separated hydrocarbon oil phase to further processing.
15. The process of claim 14, wherein the hydrocarbon oil is washed
with a polar solvent.
16. The process of claim 1, wherein the residual sulfur content of
the hydrocarbon oil after the process is less than about 3 wt
%.
17. The process of claim 16, wherein the residual sulfur content of
the hydrocarbon oil after the process is less than about 2.5 wt
%.
18. The process of claim 14, wherein the residual sulfur content of
the hydrocarbon oil after the process is less than about 2.0 wt %.
Description
BACKGROUND
[0001] Petroleum is the world's main source of hydrocarbons used as
fuel and petrochemical feedstock. Because of the presence of
impurities, crude oil is seldom used in the form produced at the
well, but rather, is typically converted in oil refineries into the
wide range of fuels and petrochemicals appropriate for their
intended end-use applications.
[0002] While compositions of natural petroleum or crude oils vary
significantly, all crudes contain sulfur compounds. Generally,
sulfur concentrations in crude oils range from about 0.5 to about
1.5 percent, but may deviate upwardly to up to about 8 percent.
When combusted, sulfur containing compounds are converted to sulfur
oxides (SOx), considered to be an environmental pollutant.
Catalytic oxidation of sulfur and the subsequent reaction thereof
with water can result in the formation of sulfuric acid mist,
thereby also contributing to particulates emission. And so, such
crudes typically must be desulfurized to yield products, which meet
performance specifications and/or environmental standards.
[0003] In fact, it is likely that sulfur removal from petroleum
feedstocks and products will become increasingly important in years
to come. While legislation on sulfur in diesel fuel, for example,
in Europe, Japan and the US has recently lowered the specification
for on-road vehicles from 0.05 to 0.001 (EU) or 0.0015 (US) percent
by weight, indications are that future specifications may go below
this level and include off-road vehicles.
[0004] A variety of methods have been reported to reduce the amount
of sulfur in crude oil. Some of these include one or more of the
use of ozone, or peroxides, either alone, or in the presence of
molybdenum or tungsten metal catalysts. However, the use of
peroxide and ozone can introduce undesirable handling issues into
the manufacturing environment, and both are expensive. Adding
molybdenum and tungsten catalysts does increase the percentage of
sulfur removable by peroxide processes, but adds to the cost, in
some applications, prohibitively.
[0005] Efficient, more cost effective, methods for removal of
sulfur compounds from hydrocarbon oils are thus needed. The
usefulness of such methods could be further leveraged if they
required only mild conditions, so that implementation in
manufacturing environments would not introduce substantial handling
issues.
BRIEF DESCRIPTION
[0006] Provided herein are processes for desulfurization of a
hydrocarbon oil and oil distillates. The processes comprise
providing a hydrocarbon oil comprising sulfur impurities and mixing
the hydrocarbon oil with a phase transfer agent and a source of
hypochlorite ion source to provide a mixture. The mixture is
allowed to separate into an aqueous hypochlorite phase and a
non-polar oil phase and the phases separated from each other.
DRAWINGS
[0007] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0008] FIG. 1 is a flow chart schematically illustrating one
embodiment of the present process;
[0009] FIG. 2 is a flow chart schematically illustrating another
embodiment of the present process;
[0010] FIG. 3 is a flow chart schematically illustrating another
embodiment of the present process;
[0011] FIG. 4 is a flow chart schematically illustrating another
embodiment of the present process;
[0012] FIG. 5 is a flow chart schematically illustrating another
embodiment of the present process;
[0013] FIG. 6 is a flow chart schematically illustrating another
embodiment of the present process;
[0014] FIG. 7 is a flow chart schematically illustrating another
embodiment of the present process; and
[0015] FIG. 8 is a flow chart schematically illustrating another
embodiment of the present process.
DETAILED DESCRIPTION
[0016] Unless defined otherwise, technical and scientific terms
used herein have the same meaning as is commonly understood by one
of skill in the art to which this invention belongs. The terms
"first", "second", and the like, as used herein do not denote any
order, quantity, or importance, but rather are used to distinguish
one element from another. Also, the terms "a" and "an" do not
denote a limitation of quantity, but rather denote the presence of
at least one of the referenced item, and the terms "front", "back",
"bottom", and/or "top", unless otherwise noted, are merely used for
convenience of description, and are not limited to any one position
or spatial orientation. If ranges are disclosed, the endpoints of
all ranges directed to the same component or property are inclusive
and independently combinable (e.g., ranges of "up to about 25 wt.
%, or, more specifically, about 5 wt. % to about 20 wt. %," is
inclusive of the endpoints and all intermediate values of the
ranges of "about 5 wt. % to about 25 wt. %," etc.). The modifier
"about" used in connection with a quantity is inclusive of the
stated value and has the meaning dictated by the context (e.g.,
includes the degree of error associated with measurement of the
particular quantity).
[0017] Provided herein are processes for desulfurization of
hydrocarbon oil and/or oil distillates. The processes comprise
mixing the hydrocarbon oil or the oil distillate with a phase
transfer agent and source of hypochlorite ions to provide a
mixture. The mixture separates into an aqueous hypochlorite phase
and a non-polar oil phase. The hypochlorite phase is then removed
from the treated oil phase, and, if desired, the oil phase
centrifuged and separated from any precipitate, thereby providing a
clean oil phase.
[0018] The processes disclosed herein may advantageously be applied
to any hydrocarbon oil or oil distillate, or mixture of one or more
hydrocarbon oils and/or oil distillates, comprising sulfur
impurities. As those of ordinary skill in the art are aware,
hydrocarbon oils are normally classified into 6 classes, according
to the oil's boiling point, purpose and composition. The boiling
point, ranging from about 175.degree. C. to about 600.degree. C.,
and carbon chain length, ranging from about 20 carbon atoms to
about 70 carbon atoms, of the oil increases with the fuel oil
number. Viscosity also increases with fuel oil number and the
heaviest oil, fuel oil no. 6, typically must be heated in order to
flow.
[0019] Exemplary hydrocarbon oils suitable for the present
invention include any of fuel oil nos 1-6 regardless of their
source, for example, petroleum, liquid oils obtained from bitumen
(often called tar sands or oil sands), oil shale, or coal, as well
as synthetic crude oils produced by the liquefaction of coal, heavy
crude oils, and petroleum refinery residual oil fractions, such as
bottoms or fractions produced by atmospheric and vacuum
distillation of crude oil.
[0020] Examples of oil distillates include in particular, No. 1
fuel oil, No. 2 fuel oil and No. 3 fuel oil, which may also be
referred to as distillate fuel oils, diesel fuel oils, light fuel
oils, or gasoil. For example, No. 2 fuel oil, No. 2 distillate and
No. 2 diesel fuel oil are approximately the same, with diesel
differing only in that it also has a cetane number limit which
described ignition quality of the fuel. Hydrocarbon oils comprising
high levels of sulfur impurities, such as Saudi oils, e.g.,
typically having sulfur contents of greater than 3 wt %, or Coker
oils, can find particular benefit from application of the present
processes.
[0021] The hydrocarbon oil desirably desulfurized by the present
process is mixed with a phase transfer agent. A phase transfer
agent is an agent which can facilitate the migration of a reactant,
in this case the sulfur impurities, in a heterogeneous system from
one phase, e.g., the oil phase, into another phase, e.g., the
hypochlorite ion phase, where the desired reaction can take place.
As such, suitable phase transfer agents may typically facilitate
the separation of any sulfur impurities from the hydrocarbon oil,
while the hypochlorite ion source may typically oxidize the sulfur
impurities to form, e.g., sulfones. Some phase transfer agents may
also function as catalysts, i.e., may facilitate the acceleration
of the reaction of the hypochlorite ion source with any sulfur
impurities within the hydrocarbon oil, typically once the sulfur
impurities have migrated into the phase comprising the hypochlorite
ion source.
[0022] Any phase transfer agent may be used, whether or not also
active as a catalyst, and many of these, including those that are
cationic, anionic or nonionic, are known to those of ordinary skill
in the art. Cationic, anionic and nonionic surfactants, for
example, can act as phase transfer agents, and any of these may be
used in the present process. In some embodiments, cationic phase
transfer agents, such as quaternary ammonium salts, quaternary
phosphonium salts and crown ethers, may desirably be used.
Particular examples of these include, but are not limited to,
tetrabutyl ammonium bromide, tetrabutyl ammonium hydrogen sulfate,
tributylmethyl ammonium chloride, benzyltrimethyl ammonium
chloride, benzyltriethyl ammonium chloride, methyltricaprylyl
ammonium chloride, dodecyltrimethyl ammonium bromide, tetraoctyl
ammonium bromide, cetyltrimethyl ammonium chloride,
trimethyloctadecyl ammonium hydroxide, and hexaethylguanidinium
bromide. Quaternary ammonium halides are particularly suitable for
use in some embodiments, and of these, cetyltrimethylammonium
bromide (CETAB) and tetrabutylammonium bromide (TBAB) are
particularly well suited.
[0023] Any amount of the phase transfer agent may be utilized, but
at a minimum, the amount utilized will facilitate the migration of
any sulfur impurities within the hydrocarbon oil into a phase
comprising the hypochlorite ion source. Such amounts are expected
to include amounts as low as about 0.01 wt % (based on amount of
the hypochlorite ion source. Further, the amount of the phase
transfer agent to be used is not particularly limited, and may only
be limited by practical considerations. Generally speaking then,
useful amounts of the phase transfer agent are expected to range
from about 0.01 wt % to about 1.0 wt %, or from about 0.05 wt % to
about 0.8 wt %, or from about 0.05 wt % to about 0.5 wt %.
[0024] The phase transfer agent may desirably be provided as, and
added to, the hydrocarbon oil, as a solution. If the same is
desired, any solvent for the phase transfer agent may be used, and
selection of the same will thus necessarily depend on the phase
transfer agent selected. Any solvent utilized will also desirably
not interfere with ability of the phase transfer agent to
facilitate the migration of any sulfur impurities within the
hydrocarbon oil into a phase comprising the hypochlorite ion source
and/or the reaction between the hypochlorite ion source and sulfur
compounds within the hydrocarbon oil.
[0025] Examples of suitable solvents for the phase transfer agent
generally include aprotic polar solvents such as acetonitrile,
nitromethane, water, or combinations of these. However, any solvent
in which the desired amount of phase transfer agent is soluble may
be utilized. Further, the solubility of the phase transfer agent
within the solvent may be facilitated by, e.g., heating the
solvent, so that solvents in which the phase transfer agent
exhibits a lower solubility than those listed above can be
utilized, if desired. In some embodiments, water is particularly
well suited for use, and advantageously is readily available and
cost effective. However, it is to be understood that, within the
context of the present application, the particular solvent
utilized, if any, is not critical. What is important is that an
effective amount of the phase transfer agent is brought into
contact, however said contact is achieved, with any sulfur
impurities in the hydrocarbon oil so the phase transfer agent can
facilitate the migration of the sulfur impurities from the
hydrocarbon oil into the hypochlorite ion phase.
[0026] If provided in solution, the phase transfer agent is
provided in the desired solvent in a concentration of from about
0.05 wt % to about 1.0 wt %, or from about 0.1 wt % to about 0.8 wt
%, or from about 0.1 wt % to about 0.6 wt %.
[0027] Advantageously, a hypochlorite ion source is provided, and
may be added to the hydrocarbon oil, phase transfer agent, and/or
mixture comprising the hydrocarbon oil and phase transfer agent.
That is, the hypochlorite ion source may be added directly to the
hydrocarbon oil prior to the addition of the phase transfer agent,
may be added to the phase transfer agent prior to mixing with the
hydrocarbon oil, or, may be added to the mixture once the phase
transfer agent and hydrocarbon oil have been placed in contact, or
combinations of these. Suitable hypochlorite sources include those
capable of oxidizing at least a portion of the sulfur compounds
within the hydrocarbon oil. Examples of such hypochlorite ion
sources include sodium hypo chlorite, calcium hypo chlorite,
potassium hypochlorite, and hypochlorous acid.
[0028] After the hypochlorite ion source and/or phase transfer
agent is added to the hydrocarbon oil/mixture, the mixture may
desirably be agitated to facilitate contact of the components
thereof. That is, the mixture may be sonicated, vibrated,
centrifuged, or may simply be shaken.
[0029] The present process desirably removes a substantial portion
of any sulfur containing impurities within the hydrocarbon oil, as
may be present in the oil naturally, or, as may be created as
residue from atmospheric/vacuum distillation processes. Typical
sulfur containing impurities present in hydrocarbon oils, and
desirably removed by the present process include, but are not
limited to, organic sulfur-containing compounds, such as alkyl
sulfides or aromatic sulfur containing compounds. Examples of
organic sulfur-containing compounds that may typically contaminate
hydrocarbon oil and oil distillates, and that are desirably removed
therefrom, include thiophene and its derivatives. Exemplary
derivatives of thiophene include various substituted
benzothiophenes, dibenzothiophenes, phenanthrothiophenes,
benzonapthothiophenes, thiophene sulfides, and the like.
[0030] Advantageously, added heat and pressure are not necessary
for carrying out the present process. However, application of
either or both may facilitate either or both of the reaction of the
phase transfer agent with any sulfur containing impurities within
the hydrocarbon oil, and/or dissolution of any sulfones created by
the reaction therebetween within the hypochlorite ion source, and
so, the present process may optionally include the same. If so
desired, the hydrocarbon oil, phase transfer agent/solution,
hypochlorite ion source, and/or mixture may be provided with a
temperature of at least about 15.degree. C., or from about
20.degree. C. to about 50.degree. C., or even from about 20.degree.
C. to about 35.degree. C. The hydrocarbon oil, phase transfer
agent/solution, hypochlorite ion source, and/or mixture may also be
provided with a pressure of at least about 1 atmosphere, or from
about 1 atmosphere to about 5 atmospheres, or even from about 1
atmosphere to about 2 atmospheres.
[0031] Once all of the components have been added to a mixture
comprising the hydrocarbon oil, phase transfer agent/solution and
hypochlorite ion source and agitated, the mixture will typically
separate into two phases--a hydrocarbon oil phase, and an aqueous
phase containing the hypochlorite ion source and the reaction
products of the reaction between the hypochlorite ion source and
any sulfur impurities in the hydrocarbon oil. Such reaction
products may typically comprise chloride ions and sulfones. These
two layers are then desirably separated so that the clean
hydrocarbon oil may be further processed, if desired. More
particularly, the layers may be separated by any suitable method or
apparatus known in the art, such as by decantation, centrifugation
or using a separatory funnel or a mixer-settler.
[0032] Thereafter, the hydrocarbon oil treated by the disclosed
process may be delivered to a point-of-use, or, may be subjected to
further processing, or to be re-treated via one or more steps of
the disclosed process. Similarly, and once separated from the
biphasic mixture, the hypochlorite ion source may be recycled
either for use in the present process, or downstream processes.
[0033] The hydrocarbon oil may be retreated by all or a portion of
the present process. As would be appreciated by one skilled in the
art, the number of times the process is performed can be dependent
on the desired purity of the final hydrocarbon product, and one or
more of the contacting steps can be repeated until the desired
purity has been substantially achieved. Or, in another exemplary
embodiment, the treated oil can have added thereto an additional
amount of a polar solvent, which is expected to be capable of
solubilizing at least a portion of any remaining reaction products
from the oxidation/reaction of sulfur impurities by/with the
hypochlorite ion source. If the same is desired, any aprotic polar
solvent may be utilized, including those listed above in connection
the discussion of a solvent for the phase transfer agent, i.e.,
acetonitrile, nitromethane, water, or combinations of these. The
oil/solvent mixture may be agitated, if desired, and then allowed
to separate into a solvent phase and an oil phase.
[0034] The present process is expected to be less costly and
complicated than conventional processes for the removal of sulfur
impurities from hydrocarbon oils, such as for example,
hydrodesulfurization. Further, the present process makes use of
materials that are readily and economically available in bulk
quantities. And, the materials used in the process do not present
significant handling and safety issues, at least relative to
materials used in conventional desulfurization processes, e.g.,
peroxides and ozone.
[0035] The disclosed process is capable of removing substantially
all of the sulfur impurities from hydrocarbon oil (e.g. to a level
of less than about 1% by weight) from a hydrocarbon oil having
greater than 3% sulfur content. Aspects of the present invention
are particularly useful for gas turbine applications where it is
often desirable to lower the sulfur impurity content from 4% by
weight sulfur (or greater) to less than about 1% by weight
sulfur.
[0036] Referring now to FIG. 1, one embodiment of the disclosed
process for removing sulfur impurities from hydrocarbon oil is
shown in flow chart form. More specifically, FIG. 1 shows process
100, wherein hydrocarbon oil comprising sulfur impurities is
provided at step 101. The sulfur impurities capable of being
removed by process 100 include one or more of alkyl- and
arylsulfides, thiophenes, benzothiophenes, and
dibenzothiophenes.
[0037] The hydrocarbon oil is combined with a phase transfer agent,
or phase transfer agent solution, and a hypochlorite ion source as
shown at step 102. The phase transfer agent will desirably be one
capable of facilitating the migration of any sulfur impurities
within the hydrocarbon oil into a phase comprising the hypochlorite
ion source. Typically, phase transfer agents so capable can include
cationic, anionic or nonionic surfactants, and include in
particular, cationic quaternary ammonium salts, e.g. quaternary
ammonium halides such as cetyltrimethylammonium bromide (CETAB) and
tetrabutylammonium bromide (TBAB). The phase transfer agent may
desirably be provided in solution with a polar solvent, such as,
e.g., water. The ratio of the polar solvent to the phase transfer
agent will depend upon the phase transfer agent and polar solvent
selected, and may be, e.g., from about 100:1 to about 10:1.
[0038] The hypochlorite ion source will desirably be one capable of
oxidizing, or otherwise reacting with, any sulfur impurities in the
oil. Any source of a hypochlorite ion may be used, including sodium
hypochlorite or calcium hypochlorite, for example. The mixture is
then allowed to separate into two phases at step 103, i.e., an
aqueous hypochlorite phase and a non-polar oil phase.
[0039] The components of the mixture can be combined in any order,
as is illustrated further by the embodiment of the present process
shown in FIG. 2. As shown in FIG. 2, process 200 comprises
providing the hydrocarbon oil to be desulfurized, at step 201. In
the embodiment shown in FIG. 2, at step 202, the hypochlorite ion
source is added to the hydrocarbon oil to provide a mixture, and
the phase transfer agent/solution added thereto at step 203. The
mixture is then allowed to separate into two phases at step
204.
[0040] Or, as shown in FIG. 3, the process 300 may comprise
combining the hydrocarbon oil with the desired phase transfer agent
to provide a mixture at step 302, and then, at step 303, adding the
hypochlorite ion source to the mixture. The mixture may then be
allowed to separate into two phases, as shown at step 304.
[0041] Or, as shown in FIG. 4, process 400 may comprise combining
the desired hypochlorite ion source with the desired phase transfer
agent to provide a mixture at step 402. The hydrocarbon oil may
then be added to the mixture at step 403, and the mixture allowed
to separate into phases, as shown at step 404.
[0042] The present process may also comprise removing the cleaned
hydrocarbon oil from the mixture, as shown in FIG. 5. More
particular, and as shown in FIG. 5, process 500 may comprise
providing a hydrocarbon oil desirably subjected to the present
process at step 501. The hydrocarbon oil is combined with the
desired hypochlorite ion source and phase transfer agent to provide
a mixture at step 502. A mixture is then allowed to separate into
two phases, as expected to occur upon standing for e.g., 5 minutes,
at step 503. The two phases, a clean hydrocarbon oil phase and a
hypochlorite ion source phase, may then be separated, as by
decantation, as shown at step 504.
[0043] In order to facilitate contact among the components of the
mixture, the mixture may be agitated after each addition. One such
embodiment is shown in FIG. 6, wherein process 600 comprises
providing a hydrocarbon oil having sulfur impurities desirably
removed therefrom at step 601. At step 602, the hydrocarbon oil is
combined with the desired hypochlorite ion source and phase
transfer agent to provide a mixture. The mixture is then agitated
at step 603. The agitation can be provided by any suitable method
known in the art, such as, e.g., sonication, vibration,
centrifugation, manual shaking, and the like. The mixture is then
allowed to separate into phases at step 604.
[0044] In some embodiments, it may be desirable to repeat certain
steps of the present process. Repetition of the process can further
reduce the amount of sulfur impurities in the hydrocarbon oil so
that more pure fractions may be obtained, or cruder grades of
hydrocarbon oils may be started with. One such embodiment is shown
in FIG. 7, wherein once the phases are separated at step 704, the
hydrocarbon oil is recycled through the process. That is, the clean
hydrocarbon oil phase separated at step 704 from the hypochlorite
ion source phase is once again combined with a phase transfer agent
and hypochlorite ion source to provide a mixture as shown at step
702, and then the mixture allowed to separate into two phases, as
shown at step 703. The phases are then separated again at step 704
and the clean hydrocarbon oil can either be recycled again through
the process as shown at step 705, subjected to further processing,
or dispensed to a point-of-use.
[0045] Or, once the phases are separated from each other, the
hypochlorite ion source may be recycled and reused in the process
as shown in FIG. 8. As shown, process 800 involves providing a
hydrocarbon oil comprising sulfur impurities at step 801, and
combining the hydrocarbon oil with a hypochlorite ion
source/recycled hypochlorite ion source and phase transfer agent at
step 802. The mixture is allowed to separate into two phases at
step 803, and the hypochlorite ion phase separated from the
mixture, leaving the clean oil phase, at step 804. The hypochlorite
ion source may then be recycled into the process as shown at step
806, and the clean hydrocarbon oil subjected to further processing
as shown at step 805.
[0046] For example, the treated hydrocarbon oil can be washed with
a polar solvent, which is expected to be capable of solubilizing at
least a portion of any remaining reaction products from the
oxidation/reaction of sulfur impurities by/with the hypochlorite
ion source. If the same is desired, any aprotic polar solvent may
be utilized, including those listed above in connection the
discussion of a solvent for the phase transfer agent, i.e.,
acetonitrile, nitromethane, water, or combinations of these.
Example #1
[0047] To a 250 ml Erlenmeyer flask, 5.58 g of fuel (Saudi oil or
Coker oil, having an initial concentration of sulfur impurities of
from about 3 wt % to about 3.6 wt %) was weighed. The oil was
heated to 50.degree. C. in a hot water bath. A phase-transfer agent
solution was prepared by dissolving 0.0116 g of
Cetyltrimethylammonium bromide (CETAB) [CAS# 57-09-0;
CH.sub.3(CH.sub.2).sub.15N(CH.sub.3).sub.3Br; FW=364.46] in 3 g of
DI water. The agent solution was added to the oil at
.about.50.degree. C. and mixed vigorously. 165 ml of bleach
(calcium hypochlorite at 51 g/liter concentration) at 50.degree. C.
was used to extract the sulfur-containing impurities from the
mixture by shaking the mixture in a 250 ml reparatory funnel. The
mixture was then allowed to stand for five minutes, resulting in
the formation of two phases which were then separated by decanting
off the hypochlorite ion source phase. Thereafter, the oil phase
was emptied into a centrifuge tube and centrifuged at 2000 rpm for
10 minutes. The "clean oil" phase was submitted for total sulfur
analysis.
Example #2
[0048] To a 250 ml Erlenmeyer flask, 5.58 g of fuel (Saudi oil or
Coker oil, having an initial concentration of sulfur impurities of
from about 3 wt % to about 3.6 wt %) was weighed. The oil was
heated to 50.degree. C. in a hot water bath. A phase-transfer agent
solution was prepared by dissolving 0.0116 g of Tetrabutylammonium
bromide (TBAB) [CAS# 1643-19-2;
(CH.sub.3(CH.sub.2).sub.3).sub.4N(Br); FW=322.37] in 3 g of DI
water. The agent solution was added to the oil at .about.50.degree.
C. and mixed vigorously. 165 ml of bleach (calcium hypochlorite at
51 g/liter concentration) at 50.degree. C. was used to extract the
sulfur-containing impurities from the mixture by shaking the
mixture in a 250 ml reparatory funnel. The mixture was then allowed
to stand for five minutes, resulting in the formation of two phases
which were then separated by decanting off the hypochlorite ion
source phase. After decanting off the aqueous phase, the oil phase
was emptied into a centrifuge tube and centrifuged at 2000 rpm for
10 minutes. The "clean oil" phase was submitted for total sulfur
analysis.
[0049] The data from Examples 1 and 2 is summarized below in Table
1.
TABLE-US-00001 TABLE 1 Phase Sulfur concentration transfer in
treated oil Example Oil agent .mu.g/g wt % S 1 Coker CETAB 26000
+/- 300 2.6 2 Coker TBAB 16000 +/- 300 1.6 3 Saudi TBAB 13000 +/-
300 1.3 4 Saudi CETAB 18000 +/- 300 1.8
Further washing of sample 4 with 200 ml de-ionized water reduced
the sulfur content to 1.6 wt %. As used herein, the term "washing"
is meant to indicate that the water was added to the treated oil,
the oil/water mixture agitated, allowed to separate into an oil
phase and a water phase, and the oil and water phase separated.
[0050] While various embodiments of the present invention have been
shown and described herein, it will be understood that such
embodiments are provided by way of example only and not of
limitation. Numerous variations, changes and substitutions will
occur to those skilled in the art without departing from the
teaching of the present invention. Accordingly, it is intended that
the invention be interpreted within the full spirit and scope of
the appended claims.
* * * * *