U.S. patent application number 10/662817 was filed with the patent office on 2005-09-01 for process for desulfurization without consumption of hydrogen.
This patent application is currently assigned to Institut Francais du Petrole. Invention is credited to Briot, Patrick, Chapus, Thierry, Forestiere, Alain, Llido, Eric, Morel, Frederic.
Application Number | 20050189261 10/662817 |
Document ID | / |
Family ID | 31897422 |
Filed Date | 2005-09-01 |
United States Patent
Application |
20050189261 |
Kind Code |
A1 |
Briot, Patrick ; et
al. |
September 1, 2005 |
Process for desulfurization without consumption of hydrogen
Abstract
The desulfurization of a hydrocarbon-containing fraction, e.g.
kerosene or gas oil that comprises at least one stage of treatment
of said fraction with an oxidizing agent in the presence of a
catalyst of said oxidation, in which said catalyst comprises at
least one oxide of chemical formula MxOy, whereby M is an element
that is selected from the group that consists of the elements of
groups IV-B, V-B or VI-B of the periodic table.
Inventors: |
Briot, Patrick; (Pommier de
Beaurepaire, FR) ; Forestiere, Alain; (Vernaison,
FR) ; Chapus, Thierry; (Lyon, FR) ; Morel,
Frederic; (Francheville, FR) ; Llido, Eric;
(Communay, FR) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD.
SUITE 1400
ARLINGTON
VA
22201
US
|
Assignee: |
Institut Francais du
Petrole
1 et 4 avenue de Bois-Preau
Rueil Malmaison Cedex
FR
92852
|
Family ID: |
31897422 |
Appl. No.: |
10/662817 |
Filed: |
September 16, 2003 |
Current U.S.
Class: |
208/243 ;
208/196; 208/240; 208/249 |
Current CPC
Class: |
C10G 53/14 20130101;
C10G 27/12 20130101 |
Class at
Publication: |
208/243 ;
208/196; 208/249; 208/240 |
International
Class: |
C10G 027/04; C10G
029/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 16, 2002 |
FR |
02/11.472 |
Claims
1. A process for desulfurization of a hydrocarbon-containing
fraction process comprising at least one treatment stage of said
fraction with an oxidizing agent in the presence of a catalyst of
said oxidation, in which said catalyst is in bulk form and
comprises an active phase consisting essentially of at least one
metallic oxide of chemical formula M.sub.xO.sub.y, wherein M is an
element that is selected from the group that consists of the
elements of groups IV-B, V-B or VI-B of the periodic table.
2. A process for desulfurization according to claim 1, in which
said hydrocarbon-containing fraction is a petroleum fraction whose
boiling points are between 150 and 500.degree. C.
3. A process for desulfurization according to claim 1, in which
said hydrocarbon-containing fraction comprises a fraction by weight
of sulfur-containing compounds of between 5 ppm and 5%.
4. A process for desulfurization according to claim 1, in which the
temperature of said oxidation reaction is between 40.degree. C. and
300.degree. C.
5. A process for desulfurization according to claim 1, in which the
temperature of said oxidation reaction is greater than or equal to
100.degree. C.
6. A process for desulfurization according to claim 1, in which the
pressure of said oxidation reaction is between 0.1 and 5 MPa.
7. A process for desulfurization according to claim 1, in which
element M is selected from the group that consists of vanadium,
chromium, zirconium, molybdenum, tungsten, and titanium, and
combination thereof.
8. A process for desulfurization according to claim 1, in which the
active phase of said catalyst consists essentially of MoO.sub.3,
V.sub.2O.sub.5 or ZrO.sub.2 or mixtures thereof.
9. A process for desulfurization according to claim 1, in which
said catalyst is used in the form of powder, balls or
extrudates.
10. A process for desulfurization according to claim 1, in which
said oxidizing agent is selected from the group that consists of
peroxides, hydroperoxides, organic peracids, ozone, oxygen,
nitrogen oxides and metallic oxidizing agents, by themselves or in
a combination.
11. A process for desulfurization of a sulfur-containing
hydrocarbon-containing fraction that comprises at least the
following stages: a) an oxidation of at least a portion of the
sulfur-containing compounds contained in said
hydrocarbon-containing fraction in the presence of at least one
oxidizing agent and a catalyst according to claim 1, b) a
separation of the oxidized sulfur-containing compounds of the
products obtained from stage a) by extraction, distillation or
adsorption.
12. A process for desulfurization according to claim 11, in which
stage b) comprises an adsorption step carried out in at least one
adsorbent column, wherein said adsorbent is selected from the group
consisting of amorphous oxides, amorphous aluminas, amorphous
silicas amorphous silica-aluminas, crystallized oxides, zeolites,
clays or a mixture of at least two of the adsorbents of said
group.
13. A process for desulfurization according to claim 11 also
comprising a separation stage of said catalyst between oxidation
stage a) and separation stage b).
14. A process according to claim 1, wherein the hydrocarbon
fraction is kerosene or gas oil.
15. A process for desulfurization according to claim 10, in which
the active phase of said catalyst consists essentially of
MoO.sub.3, V.sub.2O.sub.5 or ZrO.sub.2 or mixtures thereof.
16. A process according to claim 15, wherein the oxidizing agent is
hydrogen peroxide tertiary butyl hydroperoxide, or cumene.
17. A process for desulfurization according to claim 2, in which
the temperature of said oxidation reaction is greater than or equal
to 100.degree. C.
18. A process for desulfurization according to claim 8, in which
the temperature of said oxidation reaction is greater than or equal
to 100.degree. C.
19. A process for desulfurization according to claim 16, in which
the temperature of said oxidation reaction is greater than or equal
to 100.degree. C.
20. A process for desulfurization according to claim 11, in which
the temperature of said oxidation reaction is greater than or equal
to 100.degree. C.
21. A process according to claim 1, wherein the bulk form is in the
form of balls, extrudates or powder.
22. A process according to claim 19, wherein the bulk form is in
the form of balls, extrudates or powder.
23. A process according to claim 20, wherein the bulk form is in
the form of balls, extrudates or powder.
24. A process according to claim 11, wherein the bulk form is
powder and the process comprising an intermediate step of removing
the powder prior to the adsorption step.
25. A process according to claim 11, wherein water forms during the
oxidation step and wherein the process further comprises a step of
removing the water before the adsorption step.
Description
[0001] This invention relates to a process for desulfurization of
hydrocarbon-containing fractions that contain sulfur with contents
that are at least greater than 5 ppm and that can go up to 5% by
weight. This process finds its application in particular in the
treatment of petroleum fractions whose boiling points are typically
higher than 150.degree. C. and even 200.degree. C. In particular,
this process advantageously makes it possible to desulfurize a
kerosene or a gas oil that is obtained from the distillation of
crude oil or in general any product that is obtained partly or
completely from a process for converting a petroleum residue.
[0002] Because of environmental requirements, official provisions
in the industrialized countries limit the sulfur content in fuels,
and more particularly the fuels such as the gas oils, in an
increasingly restrictive way. The European specifications impose,
for example, a sulfur content in the gas oils that is less than 50
ppm (portion per million) at present, while this limitation should
certainly reach 10 ppm in the near future.
[0003] To reach this objective, a process for hydrodesulfurization
by hydrogenation is routinely used by the refiner so as to
eliminate the sulfur that is contained in the ydrocarbon-containing
fraction that is to be treated. The sulfur that is present is
finally extracted from said fraction in the form of gaseous sulfur
or hydrogen sulfide. These processes generally consist in
hydrogenating the feedstock in the presence of pressurized hydrogen
(2 to 10 MPa) and at temperatures of generally between 300 to
400.degree. C., in the presence of a catalyst with a sulfide base
of cobalt and molybdenum or nickel and molybdenum.
[0004] The main problem that is linked to this type of process is
the high consumption of hydrogen thereof. This hydrogen is
generally of a limited quantity on the site of the refinery since
it is generally produced in the great majority only during a
catalytic reforming stage. Finally, since the specifications that
relate to the sulfur contents of the products that are obtained
from the refinery are set to become increasingly strict, it can be
anticipated that the production of hydrogen by the simple process
of catalytic reforming will prove to be, within the refinery,
inadequate to meet the demand.
[0005] U.S. Pat. No. 3,551,328 describes an alternative process for
desulfurization of a heavy hydrocarbon fraction that does not
consume hydrogen, in which the sulfur-containing compounds that are
contained in said fraction are oxidized in the presence of an
oxidizing agent. This oxidation can be done in the presence of a
catalyst that comprises an organometallic complex of a metal of
groups IV-B, V-B and VI-B of the periodic table. The thermal
instability of such catalysts makes it necessary, however, to carry
out the oxidation at a relatively low temperature, which produces
relatively long reaction times that are not very compatible with
the economic requirements of an industrial-scale operation.
[0006] The process that is the object of this invention proposes an
alternative solution to hydrotreatment processes. This process
comprises selectively oxidizing the sulfur-containing compounds
that are contained in a fraction or petroleum fraction into
sulfones and sulfoxides.
[0007] Upon further study of the specification and appended claims,
further objects and advantages of this invention will become
apparent to those skilled in the art.
[0008] This process uses a more stable catalyst and also makes it
possible to have oxidation periods that are short and compatible
with an industrial use.
[0009] In its more general form, the invention relates to a process
for desulfurization of a hydrocarbon-containing fraction that
comprises at least one stage of treatment of said fraction with an
oxidizing agent in the presence of a catalyst of said oxidation, in
which said catalyst comprises at least one metallic oxide of
chemical formula M.sub.xO.sub.y, whereby M is an element that is
selected from the group that consists of the elements of groups
IV-B, V-B or VI-B of the periodic table.
[0010] The catalyst is preferably in bulk form and more preferably
essentially consists of the active phase M.sub.xO.sub.y, i.e., it
is constituted at at least 70% by weight, preferably at at least
80% by weight, more preferably at at least 90% by weight, and even
at at least 98% by weight, by a metallic oxide of chemical formula
M.sub.xO.sub.y wherein x and y are dependent on the valence of
M.
[0011] The use of such a catalyst thus makes it possible to reduce
the time in which the different reaction phases are brought into
contact thanks to a temperature that according to the invention can
be between ambient temperature (about 20.degree. C.) and
200.degree. C., and even 300.degree. C. The temperature is more
preferably greater than or equal to 100.degree. C.
[0012] The hydrocarbon-containing fraction that is treated in the
process according to the invention can be obtained from the
distillation of crude oil or an effluent from the entire cracking
unit that is known to one skilled in the art. It is generally
called an atmospheric distillate and comprises the kerosene and/or
gas oil fraction. Said hydrocarbon-containing fraction is
preferably a petroleum fraction whose boiling points are between
150 and 500.degree. C. More preferably, said hydrocarbon-containing
fraction comprises a fraction by weight of sulfur-containing
compounds of between 5 ppm and 5%.
[0013] In the process of desulfurization according to the
invention, the temperature of the oxidation reaction is preferably
between 40.degree. C. and 300.degree. C. and more preferably
greater than or equal to 100.degree. C.
[0014] The pressure of this stage is preferably between 0.1 MPa and
5 MPa, more preferably between 0.1 MPa and 2 MPa, with or without
oxygen.
[0015] In the catalyst according to the invention, element M is
preferably selected from the group that consists of vanadium,
chromium, zirconium, molybdenum, tungsten, and titanium, by
themselves or in combination. Very preferably, said catalyst
comprises a molybdenum oxide. Said catalyst is preferably used in
the form of powder, balls or extrudates.
[0016] In the process for desulfurization according to the
invention, the oxidizing agent is preferably selected from the
group that consists of peroxides, hydroperoxides, organic peracids,
ozone, oxygen, nitrogen oxides and metallic oxidizing agents, by
themselves or in combination.
[0017] The process for desulfurization of a hydrocarbon fraction
according to the invention preferably comprises at least the
following stages:
[0018] a) An oxidation of at least a portion of the
sulfur-containing compounds that are contained in said
hydrocarbon-containing fraction in the presence of at least one
oxidizing agent and a catalyst according to any of the generically
or specifically described oxidation steps of the invention, and
[0019] b) A separation of the oxidized sulfur-containing compounds
of the products obtained from stage a) by extraction, distillation
or adsorption.
[0020] Stage b) is preferably an adsorption that is carried out in
at least one adsorbent column, whereby said adsorbent is selected
from among amorphous oxides such as amorphous aluminas, amorphous
silicas or amorphous silica-aluminas or from among the crystallized
oxides such as zeolites, clays, or a mixture of at least two of
these elements. More preferably, an absorbent that can be
regenerated directly by calcination will be selected.
[0021] The desulfurization process according to the invention
optionally can also comprise a stage for separation of the catalyst
between oxidation stage a) and separation stage b).
BRIEF DESCRIPTION OF THE DRAWING
[0022] The invention will be better understood by reading the
following description of a non-limiting embodiment of said
invention, schematically illustrated by the attached FIGURE.
[0023] The feedstock, for example a hydrocarbon fraction that is
obtained from the atmospheric distillation of a crude oil whose
boiling point is higher than 150.degree. C. and that contains a
sulfur fraction, is injected via line 1 into an oxidation unit A.
This unit consists of one or more reactors that operate
continuously or intermittently, i.e. batch-wise. Most often, a
system for mechanical stirring of phases present among reactors
and/or a system for recirculation (internal or external) of the
batch and/or reagents are provided so as to have the best contact
possible between the feedstock, the reagents and the catalyst.
[0024] An oxidizing agent is routed via line 2 to oxidation unit A.
An oxidation catalyst is either initially present in the unit or
injected at the same time as the oxidizing agent via line 2. This
oxidizing agent/catalyst pair is able to oxidize selectively the
sulfur-containing compounds that are contained in the hydrocarbon
fraction. By way of example, the dibenzothiophenes are oxidized
into sulfones according to the following reaction:
[Key: Oxdyant/Catalyseur=Oxidizing agent/catalyst]
[0025] The oxidizing agent that is used is advantageously selected
from the class of hydroperoxides and preferably from the group that
consists of hydrogen peroxide, tert-butyl hydroperoxide, and cumene
hydroxide.
[0026] The catalyst comprises at least one oxide of general formula
M.sub.xO.sub.y as defined above, and element M is preferably
selected from the group that consists of titanium, zirconium,
vanadium, chromium, molybdenum and tungsten. The very preferred
metallic oxides are molybdenum oxide MoO.sub.3, vanadium oxide
V.sub.2O.sub.5 or zirconium oxide ZrO.sub.2, taken either
separately or in a mixture.
[0027] The catalyst is most often used in the form of balls,
extrudates or powder, although any known form of the catalyst can
be considered within the scope of this application.
[0028] The molar ratios between the catalyst and the sulfur that
are contained in the feedstock are most often between 0.0001 and
2000, preferably between 0.001 and 100. These ratios are adjusted
by one skilled in the art based on the flow rate of the feedstock
and the average temperature of unit B.
[0029] The products of the oxidation reaction are routed via line 3
to a unit for separation of catalyst B. This operation is optional
and is justified only to the extent that the catalyst that is used
is in powdered form and routed with the oxidizing agent via line 2.
In the case of a catalyst, in the form of balls or extrudates,
already being present in unit A, for example in the form of a fixed
particle bed, this operation is generally not useful.
[0030] The products of the reaction are then sent into a water
elimination unit C via a line 4. Unit C can be a decanter, a
coalescer or any other known means that can promote an elimination
of the water that is contained in said products of the reaction.
This operation is optional, but preferred, because on the one hand,
the oxidation of the sulfur-containing compounds is generally not
done in an aqueous medium, and the other hand, said oxidation can
result in a formation of water in a small quantity that can
adversely affect the adsorbent during the following adsorption
phase. The water is evacuated via line 5.
[0031] The products that are obtained from unit C are then sent via
line 6 into a unit D for separation of sulfones and sulfoxides from
the hydrocarbon-containing medium. Although the use of a
distillation or solvent extraction solvent or any other known means
of separation is possible within the scope of this invention,
preferably an adsorption unit will be used. For example, columns
that are filled with an adsorbent will be used. The adsorbent then
advantageously comprises at least one amorphous oxide such as
alumina, silica or silica-alumina or a mixture of the latter or a
crystallized oxide such as a zeolite or a clay. It will also be
possible to employ a mixture of these compounds in adequate
proportions within the columns.
[0032] After adsorption of sulfones, the effluent, which is low in
sulfur-containing compounds, is finally recovered at the outlet of
the unit via line 7.
[0033] The following examples illustrate in a non-limiting manner
some of the advantages of this invention:
EXAMPLE 1
According to the Invention
[0034] This example demonstrates the effectiveness of this process
for eliminating sulfur-containing compounds contained in a
hydrocarbon-containing feedstock.
[0035] The feedstock is a gas oil that is obtained from a crude oil
whose distillation interval is between 150 and 350.degree. C. This
gas oil contains 2% by weight of sulfur.
[0036] The oxidizing agent/catalyst mixture is a mixture that
consists of tert-butyl hydroperoxide (38 g/liter of feedstock) and
bulk molybdenum oxide MoO.sub.3 (3.2 g/liter of feedstock). This
mixture is heated to 100.degree. C. The outlet effluent no longer
contains benzothiophene and dibenzothiophene but corresponding
sulfones and sulfoxides. This transformation was demonstrated by
gas chromatography.
[0037] The mixture that is obtained is then sent to a column that
contains an amorphous silica, previously activated under nitrogen
at 120.degree. C. This mixture is sent with an adjusted flow rate
such that the ratio of the flow rate of feedstock to the volume of
catalyst is equal to 1 liter of feedstock per liter of silica and
per hour. At the outlet of the unit, the sulfur content of the
unit, determined according to known techniques by combustion and
chemiluminescence, is equal to 5 ppm.
[0038] Several characteristics of the feedstock and the effluents
that are obtained from this process are reported in Table 1:
1 TABLE 1 Feedstock Effluents Density 0.82 0.819 Sulfur (% by
weight) 2 0.0005
[0039] This comparison shows that the process of the invention
makes it possible to obtain products that have a very low sulfur
content, according to specifications without the consumption of
hydrogen.
[0040] Example 4 demonstrates that the presence of a catalyst
according to the invention advantageously promotes the oxidation
stage of the sulfur-containing compounds compared to comparative
examples 2 and 3.
EXAMPLE 2
Oxidation without a Catalyst (For Comparison)
[0041] Two grams of oxidized water are dissolved in 20 g of
heptane. This mixture is placed in a flask on top of which is a
rising condenser. 3.6 g of acetic acid dissolved in 20 g of heptane
is added drop by drop into the flask to prepare the peracid. Then,
once the peracid is prepared, the feedstock that consists of decane
(107 g) that contains about 10% by weight of benzothiophene (1.4 g)
is added drop by drop to the peracid. Stirring of the mixture is
maintained, then it is heated first to 50.degree. C. at atmospheric
pressure for 4 hours, then to 100.degree. C. at atmospheric
pressure for 30 hours. Chromatographic analysis at a regular time
interval showed that the benzothiophene is not oxidized in a period
of at least 30 hours.
EXAMPLE 3
Oxidation with an Acid Catalyst (For Comparison)
[0042] The procedure that is used in this example is the same as in
the preceding example. 2 g of catalyst was added to the peracid
mixture before the feedstock was introduced, however. In this
example, the catalyst used is a sulfonic resin marketed by Rohm and
Haas under the trade name Amberlyst 15. The mixture was heated to
50.degree. C. at atmospheric pressure for 7 hours, then to
100.degree. C. at atmospheric pressure for 15 hours.
Chromatographic analyses showed that benzothiophene does not
oxidize even after 7 hours of heating.
EXAMPLE 4
Oxidation with a Catalyst According to the Invention
[0043] 0.28 g of molybdenum oxide is added to a peracid mixture
that is identical to that of Example 3. The mixture is heated to
100.degree. C. at atmospheric pressure while being stirred for one
hour. It appears that at the end of one hour, all of the
benzothiophene present in the feedstock has disappeared.
[0044] The preceding examples can be repeated with similar success
by substituting the generically or specifically described reactants
and/or operating conditions of this invention for those used in the
preceding examples.
[0045] The entire disclosures of all applications, patents and
publications, cited herein and of corresponding French application
No. 02/11.472, filed Sep. 16, 2002 are incorporated by reference
herein.
[0046] From the foregoing description, one skilled in the art can
easily ascertain the essential characteristics of this invention
and, without departing from the spirit and scope thereof, can make
various changes and modifications of the invention to adapt it to
various usages and conditions.
* * * * *