U.S. patent application number 16/829014 was filed with the patent office on 2020-07-16 for method for producing tetrafluoropropene.
The applicant listed for this patent is Arkema France. Invention is credited to Dominique DEUR-BERT, Dominique GARRAIT, Anne PIGAMO, Laurent WENDLINGER.
Application Number | 20200223773 16/829014 |
Document ID | / |
Family ID | 56684040 |
Filed Date | 2020-07-16 |
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United States Patent
Application |
20200223773 |
Kind Code |
A1 |
DEUR-BERT; Dominique ; et
al. |
July 16, 2020 |
METHOD FOR PRODUCING TETRAFLUOROPROPENE
Abstract
A method for preparing tetrafluoropropene utilising three
reactors is described. Each reactor comprises a catalytic bed
containing a catalyst or a preliminary catalyst. The method
comprises the implementation, separately in each of the reactors,
of catalytic reactions or reactions regenerating the catalyst, the
quantity of catalyst or preliminary catalyst in the catalytic bed
of one of the reactors representing between 90% and 110% of the
quantity of catalyst or preliminary catalyst contained in the
catalytic bed of one of the other two reactors. A facility
configured to implement the method is also described.
Inventors: |
DEUR-BERT; Dominique;
(Charly, FR) ; GARRAIT; Dominique; (Charly,
FR) ; PIGAMO; Anne; (Francheville, FR) ;
WENDLINGER; Laurent; (Soucieu en Jarrest, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Arkema France |
Colombes |
|
FR |
|
|
Family ID: |
56684040 |
Appl. No.: |
16/829014 |
Filed: |
March 25, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16099235 |
Nov 6, 2018 |
10633309 |
|
|
PCT/FR2017/051186 |
May 17, 2017 |
|
|
|
16829014 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 17/206 20130101;
Y02P 20/584 20151101; B01J 8/0278 20130101; B01J 2219/00038
20130101; B01J 8/025 20130101; C07C 17/013 20130101; B01J 19/2445
20130101; C07C 17/206 20130101; C07C 21/18 20130101 |
International
Class: |
C07C 17/20 20060101
C07C017/20; B01J 8/02 20060101 B01J008/02; B01J 19/24 20060101
B01J019/24; C07C 17/013 20060101 C07C017/013 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 2016 |
FR |
1654444 |
Claims
[0203] 1. A plant for the manufacture of tetrafluoropropene
comprising three reactors for reaction in the gas phase each
comprising a catalytic bed containing a catalyst or a preliminary
catalyst, the three reactors for reaction in the gas phase each
being configured in order to be fed by: a device for feeding with a
reaction stream comprising a compound B and hydrofluoric acid;
and/or a device for feeding with a preliminary reaction stream
comprising a compound A and hydrofluoric acid; and/or a device for
feeding with a regeneration stream configured in order to feed the
reactor with a regeneration stream comprising an oxidizing agent;
and optionally, a device for feeding with a waiting stream
configured in order to feed the reactor with an inert gaseous
stream comprising an inert gas; wherein the amount of catalyst or
of preliminary catalyst in the catalytic bed of one of the reactors
represents between 90% and 110% of the amount of catalyst or of
preliminary catalyst present in the catalytic bed of one of the
other two reactors.
2. The plant as claimed in claim 1, wherein the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is between 90% and 110% of the amount of catalyst or of
preliminary catalyst present in the catalytic bed of the other two
reactors considered independently of one another.
3. The plant as claimed in claim 1, wherein the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is identical in the three reactors.
4. The plant as claimed in claim 1, wherein the tetrafluoropropene
comprises 2,3,3,3-tetrafluoropropene or
1,3,3,3-tetrafluoropropene.
5. The plant as claimed in claim 1, comprising: a first reactor, a
second reactor and a third reactor; a first device for collecting a
stream of products resulting from the first reactor connected at
the outlet of the latter; a second device for collecting a stream
of products resulting from the second reactor connected at the
outlet of the latter; a third device for collecting a stream of
products resulting from the third reactor connected at the outlet
of the latter; a first intermediate collecting device connected to
any one of the devices for collecting stream of products resulting
from the first, second and/or third reactor and joined to the
device for feeding with preliminary reaction stream; a second
intermediate collecting device connected to any one of the devices
for collecting stream of products resulting from the first, second
and/or third reactor and joined to the separation unit; a
separation unit fed by the second intermediate collecting device; a
first collecting pipe and a second collecting pipe which are
connected at the outlet of the separation unit, the first
collecting pipe being configured in order to transport a stream
comprising hydrochloric acid and tetrafluoropropene and the second
collecting pipe being configured in order to transport a stream
comprising hydrofluoric acid and compound B; a device for feeding
with a reaction stream configured in order to feed the first
reactor, the second reactor and the third reactor, this device
being itself fed by a device for feeding with hydrofluoric acid and
optionally by the second collecting pipe; a device for feeding with
a preliminary reaction stream configured in order to feed the first
reactor, the second reactor and the third reactor, this device
being itself fed by a device for feeding with hydrofluoric acid and
optionally by the first intermediate collecting device; a device
for feeding with a regeneration stream configured in order to feed
the first reactor, the second reactor and the third reactor; a
device for collecting a stream of gas resulting from the
regeneration of the first reactor, of the second reactor and of the
third reactor.
6. The plant as claimed in claim 1, comprising: a first reactor, a
second reactor and a third reactor; a first device for collecting a
stream of products resulting from the first reactor connected at
the outlet of the latter; a second device for collecting a stream
of products resulting from the second reactor connected at the
outlet of the latter; a third device for collecting a stream of
products resulting from the third reactor connected at the outlet
of the latter; a third intermediate collecting device connected to
any one of the devices for collecting a stream of products
resulting from the first, second and/or third reactor and joined to
the device for feeding with a reaction stream; a second
intermediate collecting device connected to any one of the devices
for collecting the stream of products resulting from the first,
second and/or third reactor and joined to the separation unit; a
separation unit fed by the second intermediate collecting device; a
first collecting pipe and a second collecting pipe which are
connected at the outlet of the separation unit, the first
collecting pipe being configured in order to transport a stream
comprising hydrochloric acid and tetrafluoropropene and the second
collecting pipe being configured in order to transport a stream
comprising hydrofluoric acid and compound B; a device for feeding
with a reaction stream configured in order to feed the first
reactor, the second reactor and the third reactor, this device
being itself fed by a device for feeding with hydrofluoric acid,
and by the third intermediate collecting device and optionally by
the second collecting pipe; a device for feeding with a preliminary
reaction stream configured in order to feed the first reactor, the
second reactor and the third reactor, this device being itself fed
by a device for feeding with hydrofluoric acid and optionally by
the second collecting pipe; a device for feeding with a
regeneration stream configured in order to feed the first reactor,
the second reactor and the third reactor; a device for collecting a
stream of gas resulting from the regeneration of the first reactor,
of the second reactor and of the third reactor.
7. The plant as claimed in claim 1, wherein the reactors are made
of steel and have an interior surface covered with an alloy
comprising more than 30% by weight of nickel or with a
fluoropolymer-type coating.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S.
application Ser. No. 16/099,235, filed on Nov. 6, 2018, which is a
National Stage application of International Application No.
PCT/FR2017/051186, filed on May 17, 2017, which claims the benefit
of French Patent Application No. 1654444, filed on May 19,
2016.
FIELD OF THE INVENTION
[0002] The present invention relates to a process for the
manufacture of tetrafluoropropene (HFO-1234) and in particular of
2,3,3,3-tetrafluoropropene (HFO-1234yf), and to a plant suitable
for the implementation of this process.
TECHNOLOGICAL BACKGROUND
[0003] Greenhouse gases are gaseous components which absorb the
infrared radiation emitted by the surface of the Earth, thus
contributing to the greenhouse effect. The increase in their
concentration in the atmosphere is one of the factors causing
global warming.
[0004] The production of the chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HCFCs) used in refrigeration and air
conditioning systems has thus been successively regulated by the
Montreal protocol and then the Kyoto protocol. There exists a need
to develop new molecules which are just as effective and which in
particular exhibit the smallest possible global warming potential.
This is the case with hydrofluoroolefins and in particular
HFO-1234yf, which is a particularly useful compound.
[0005] It is known to produce hydrofluoroolefins or
hydrofluorocarbons by fluorination of hydrochloroolefins or of
hydrochlorocarbons in particular. This fluorination is generally a
catalytic fluorination using hydrofluoric acid as fluorinating
agent.
[0006] The fluorination reaction generally has to be carried out at
a high temperature (more than 300.degree. C.) in the gas phase, in
the presence of a supported or bulk solid catalyst.
[0007] It is known to provide cofeeding with an oxidizing agent, in
particular air, or optionally chlorine, in order to preserve the
lifetime of the catalyst and to limit the deposition of coke at its
surface during the reaction stage.
[0008] The document U.S. Pat. No. 8,614,361 describes a process for
the manufacture of HFO-1234yf by reacting HCFO-1233xf with HF in
the presence of a high oxygen content.
[0009] The document U.S. Pat. No. 8,618,338 describes a process for
the manufacture of fluoroolefin in two stages, in particular a
first stage of reaction in the liquid phase starting from
1,1,2,3-tetrachloropropene (HCO-1230xa), in order to obtain the
intermediate HCFO-1233xf, and a second stage of reaction in the gas
phase starting from HCFO-1233xf, in order to obtain HFO-1234yf.
[0010] The document WO 2013/088195 teaches a process for the
manufacture of HFO-1234yf in two stages, a first stage of
fluorination in the gas phase of 1,1,1,2,3-pentachloropropane
(HCC-240db) and/or of 1,1,2,2,3-pentachloropropane (HCC-240aa), in
order to obtain the intermediate HCFO-1233xf, and then a second
stage of reaction in the gas phase starting from HCFO-1233xf, in
order to obtain HFO-1234yf.
[0011] The documents WO 2012/098421 and WO 2012/098422 teach the
activation and the regeneration of fluorination catalysts.
[0012] The document WO 2013/182816 describes a chemical reaction
process for the alternating implementation of a phase of catalytic
reaction and of a phase of regeneration of catalyst in a
reactor.
[0013] The document WO2016/001515 describes a chemical reaction
process for the alternating implementation of a phase of catalytic
reaction and of a phase of regeneration of catalyst in one or more
reactors.
[0014] There still exists a need to improve the processes for the
manufacture of HFO-1234 compounds, such as HFO-1234yf, and in
particular to produce these compounds with a high yield and with a
high degree of purity while minimizing the production costs and the
capital costs.
SUMMARY OF THE INVENTION
[0015] According to a first aspect, the present invention relates
to a process for the manufacture of tetrafluoropropene employing
three reactors each comprising a catalytic bed containing a
catalyst or a preliminary catalyst and comprising the
implementation, independently in each of the reactors, of: [0016]
at least one stage of reaction in the gas phase of a compound A in
the presence of hydrofluoric acid and of a preliminary catalyst, in
order to form a compound B; [0017] at least one stage of reaction
in the gas phase of a compound B in the presence of hydrofluoric
acid and of a catalyst, in order to form the tetrafluoropropene, or
[0018] a stage of regeneration of the catalyst or of the
preliminary catalyst by bringing the latter into contact with a
regeneration stream comprising an oxidizing agent, characterized in
that the amount of catalyst or of preliminary catalyst in the
catalytic bed of one of the reactors represents between 90% and
110% of the amount of catalyst or of preliminary catalyst present
in the catalytic bed of one of the other two reactors.
[0019] Preferably, the amount of catalyst or of preliminary
catalyst present in the catalytic bed of each reactor is between
90% and 110% of the amount of catalyst or of preliminary catalyst
present in the catalytic bed of the other two reactors considered
independently of one another, advantageously between 92% and 108%,
preferably between 95% and 105%, in particular between 98% and
102%.
[0020] According to a preferred embodiment, the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is identical in the three reactors.
[0021] According to a preferred embodiment, the stage of reaction
of a compound B in the presence of hydrofluoric acid or the stage
of reaction of a compound A in the presence of hydrofluoric acid is
carried out alternately with a stage of regeneration of the
catalyst or of the preliminary catalyst.
[0022] According to a preferred embodiment, the present process
simultaneously employs: [0023] a stage of reaction of a compound A
in the presence of hydrofluoric acid in one of the three reactors;
[0024] a stage of reaction of a compound B in the presence of
hydrofluoric acid in another of the three reactors; [0025] a stage
of regeneration of the catalyst or of the preliminary catalyst or a
waiting stage in the third reactor.
[0026] According to a preferred embodiment, the process comprises:
[0027] the collecting of a stream of products on conclusion of the
stage of reaction of the compound B; [0028] the use of said stream
of products collected on conclusion of the stage of reaction of the
compound B in order to carry out the stage of reaction of the
compound A in the presence of hydrofluoric acid; and [0029] the
separation of the stream of products resulting from the stage of
reaction of the compound A in the presence of hydrofluoric acid
into a first stream comprising hydrochloric acid and
tetrafluoropropene and a second stream comprising hydrofluoric acid
and the compound B; [0030] optionally, the collecting of said
second stream comprising hydrofluoric acid and the compound B, and
the recycling of this in the stage of reaction of the compound B in
the presence of hydrofluoric acid or in the stage of reaction of a
compound A in the presence of hydrofluoric acid.
[0031] According to a preferred embodiment, the tetrafluoropropene
is 2,3,3,3-tetrafluoropropene (HFO-1234yf) or
1,3,3,3-tetrafluoropropene (HFO-1234ze).
[0032] According to a preferred embodiment, the compound A is
chosen from tetrachloropropenes, chlorotrifluoropropenes,
pentachloropropanes, dichlorotrifluoropropanes,
trichlorodifluoropropanes, tetrachlorofluoropropanes,
dichlorodifluoropropenes, trichlorofluoropropenes and the mixtures
of these; the compound B is chosen from chlorotrifluoropropenes,
pentafluoropropanes, dichlorotrifluoropropanes,
trichlorodifluoropropanes, tetrachlorofluoropropanes,
dichlorodifluoropropenes, trichlorofluoropropenes and the mixtures
of these; preferably, the compound A is selected from the group
consisting of 2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf),
2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db),
1,1,1,2,3-pentachloropropane (HCC-240db),
1,1,2,2,3-pentachloropropane (HCC-240aa),
1,1,1,3,3-pentachloropropane (HCC-240fa),
1,1,2,3-tetrachloro-1-propene (HCO-1230xa),
2,3,3,3-tetrachloro-1-propene (HCO-1230xf),
1,1,3,3-tetrachloro-1-propene (HCO-1230za) and
1,3,3,3-tetrachloro-1-propene (HCO-1230zd); and the compound B is
selected from the group consisting of
2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf),
1,1,1,2,2-pentafluoropropane (HFC-245cb) and
1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zd).
[0033] According to a second aspect, the present invention provides
a plant for the manufacture of tetrafluoropropene comprising three
reactors for reaction in the gas phase each comprising a catalytic
bed containing a catalyst or a preliminary catalyst, the three
reactors for reaction in the gas phase each being configured in
order to be fed by: [0034] a device for feeding with reaction
stream comprising a compound B and hydrofluoric acid; and/or [0035]
a device for feeding with preliminary reaction stream comprising a
chlorinated compound A and hydrofluoric acid; and/or [0036] a
device for feeding with regeneration stream configured in order to
feed the reactor with a regeneration stream comprising an oxidizing
agent; and [0037] optionally, a device for feeding with waiting
stream configured in order to feed a reactor with a gaseous stream
comprising an inert gas; characterized in that the amount of
catalyst or of preliminary catalyst in the catalytic bed of one of
the reactors is from 90% to 110% of the amount of catalyst or of
preliminary catalyst present in the catalytic bed of one of the
other two reactors.
[0038] According to a preferred embodiment, the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is between 90% and 110% of the amount of catalyst or of
preliminary catalyst present in the catalytic bed of the other two
reactors considered independently of one another, advantageously
between 92% and 108%, preferably between 95% and 105%, in
particular between 98% and 102%.
[0039] According to a preferred embodiment, the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is identical in the three reactors.
[0040] According to a preferred embodiment, the tetrafluoropropene
is 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene.
[0041] According to a preferred embodiment, the plant comprises:
[0042] a first reactor, a second reactor and a third reactor;
[0043] a first device for collecting stream of products resulting
from the first reactor connected at the outlet of the latter;
[0044] a second device for collecting stream of products resulting
from the second reactor connected at the outlet of the latter;
[0045] a third device for collecting stream of products resulting
from the third reactor connected at the outlet of the latter;
[0046] a first intermediate collecting device connected to any one
of the devices for collecting stream of products resulting from the
first, from the second and/or from the third reactor and joined to
the device for feeding with preliminary reaction stream; [0047] a
second intermediate collecting device connected to any one of the
devices for collecting stream of products resulting from the first,
from the second and/or from the third reactor and joined to the
separation unit; [0048] a separation unit fed by the second
intermediate collecting device; [0049] a first collecting pipe and
a second collecting pipe which are connected at the outlet of the
separation unit, the first collecting pipe being configured in
order to transport a stream comprising hydrochloric acid and
tetrafluoropropene and the second collecting pipe being configured
in order to transport a stream comprising hydrofluoric acid and
compound B; [0050] a device for feeding with reaction stream
configured in order to feed the first reactor, the second reactor
and the third reactor, this device being itself fed by a device for
feeding with hydrofluoric acid and optionally by the second
collecting pipe; [0051] a device for feeding with preliminary
reaction stream configured in order to feed the first reactor, the
second reactor and the third reactor, this device being itself fed
by a device for feeding with hydrofluoric acid and optionally by
the first intermediate collecting device; [0052] a device for
feeding with regeneration stream configured in order to feed the
first reactor, the second reactor and the third reactor; [0053] a
device for collecting stream of gas resulting from the regeneration
of the first reactor, of the second reactor and of the third
reactor.
[0054] According to another preferred embodiment, the plant
comprises: [0055] a first reactor, a second reactor and a third
reactor; [0056] a first device for collecting stream of products
resulting from the first reactor connected at the outlet of the
latter; [0057] a second device for collecting stream of products
resulting from the second reactor connected at the outlet of the
latter; [0058] a third device for collecting stream of products
resulting from the third reactor connected at the outlet of the
latter; [0059] a third intermediate collecting device connected to
any one of the devices for collecting stream of products and joined
to the device for feeding with reaction stream; [0060] a second
intermediate collecting device connected to any one of the devices
for collecting stream of products resulting from the first, from
the second and/or from the third reactor and joined to the
separation unit; [0061] a separation unit fed by the second
intermediate collecting device; [0062] a first collecting pipe and
a second collecting pipe which are connected at the outlet of the
separation unit, the first collecting pipe being configured in
order to transport a stream comprising hydrochloric acid and
tetrafluoropropene and the second collecting pipe being configured
in order to transport a stream comprising hydrofluoric acid and
compound B; [0063] a device for feeding with reaction stream
configured in order to feed the first reactor, the second reactor
and the third reactor, this device being itself fed by a device for
feeding with hydrofluoric acid, and by the third intermediate
collecting device and optionally by the second collecting pipe;
[0064] a device for feeding with preliminary reaction stream
configured in order to feed the first reactor, the second reactor
and the third reactor, this device being itself fed by a device for
feeding with hydrofluoric acid and optionally by the second
collecting pipe; [0065] a device for feeding with regeneration
stream configured in order to feed the first reactor, the second
reactor and the third reactor; [0066] a device for collecting
stream of gas resulting from the regeneration of the first reactor,
of the second reactor and of the third reactor.
[0067] According to a preferred embodiment, the reactors are made
of steel and have an interior surface covered with an alloy
comprising more than 30% by weight of nickel or with a coating of
fluoropolymers type; preferably, the alloy comprising more than 30%
by weight of nickel is an Incolloy.RTM., Inconel.RTM., Monel.RTM.
or Hastelloy.RTM..
BRIEF DESCRIPTION OF THE FIGURES
[0068] FIGS. 1a and 1b diagrammatically represent an embodiment of
a plant according to the invention with three reactors in different
operating configurations.
[0069] FIGS. 2a, 2b and 2c diagrammatically represent an embodiment
of a plant according to the invention with three reactors in
different operating configurations.
[0070] FIGS. 3a and 3b diagrammatically represent an embodiment of
a plant according to the invention with three reactors comprising a
device for feeding with regeneration stream at the reactor bottom
and at the reactor top, in two different configurations.
[0071] FIG. 4 diagrammatically represents an embodiment of a plant
according to the invention in which the separation unit is in a
different operating configuration.
DETAILED DESCRIPTION OF THE INVENTION
[0072] The invention is now described in greater detail and in a
nonlimiting manner in the description which follows. Unless
otherwise mentioned, the percentages and proportions shown are
values by weight. The invention provides for the production of
HFO-1234 by catalytic reaction in the gas phase; this catalytic
reaction is, according to the invention, alternated with the
regeneration of the catalyst. In some embodiments, the invention
provides for the production of HFO-1234 in several stages.
[0073] According to a first aspect of the present invention, a
process for the manufacture of tetrafluoropropene is provided. Said
process for the manufacture of tetrafluoropropene employs three
reactors each comprising a catalytic bed containing a catalyst or a
preliminary catalyst and comprises the implementation,
independently in each of the reactors, of: [0074] at least one
stage of reaction in the gas phase of a compound A in the presence
of hydrofluoric acid and of a preliminary catalyst, in order to
form a compound B; [0075] at least one stage of reaction in the gas
phase of a compound B in the presence of hydrofluoric acid and of a
catalyst, in order to form the tetrafluoropropene, or [0076] a
stage of regeneration of the catalyst or of the preliminary
catalyst by bringing the latter into contact with a regeneration
stream comprising an oxidizing agent.
[0077] Preferably, the amount of catalyst or of preliminary
catalyst in the catalytic bed of one of the reactors is from 90% to
110% of the amount of catalyst or of preliminary catalyst present
in the catalytic bed of one of the other two reactors.
[0078] According to a preferred embodiment, the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is between 90% and 110% of the amount of catalyst or of
preliminary catalyst present in the catalytic bed of the other two
reactors considered independently of one another, advantageously
between 92% and 108%, preferably between 95% and 105%, in
particular between 98% and 102%.
[0079] According to a specific embodiment, the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is identical in the three reactors. Preferably, the
catalyst is the same catalyst as the preliminary catalyst.
[0080] Said catalyst or said preliminary catalyst used in the
present process can, for example, be based on a metal comprising a
transition metal oxide or a derivative or a halide or an oxyhalide
of such a metal. Mention may be made, for example, of FeCl.sub.3,
chromium oxyfluoride, chromium oxides (optionally subjected to
fluorination treatments), chromium fluorides and their mixtures.
Other possible catalysts are catalysts supported on carbon,
antimony-based catalysts or aluminum-based catalysts (for example
AlF.sub.3 and Al.sub.2O.sub.3, aluminum oxyfluoride and aluminum
fluoride).
[0081] Use may be made in general of a chromium oxyfluoride, an
aluminum fluoride or oxyfluoride, or a supported or nonsupported
catalyst containing a metal such as Cr, Ni, Fe, Zn, Ti, V, Zr, Mo,
Ge, Sn, Pb, Mg or Sb. Reference may be made, in this regard, to the
document WO 2007/079431 (on p. 7, 1. 1-5 and 28-32), to the
document EP 939 071 (section [0022]), to the document WO
2008/054781 (on p. 9, 1. 22-p. 10, 1. 34) and to the document WO
2008/040969 (claim 1), to which documents reference is expressly
made.
[0082] The catalyst is more particularly preferably chromium-based
and it is more particularly a mixed catalyst comprising
chromium.
[0083] According to one embodiment, use is made, for any one of the
reaction stages, of a mixed catalyst comprising chromium and
nickel. The Cr/Ni molar ratio (on the basis of the metal element)
is generally from 0.5 to 5, for example from 0.7 to 2, for example
approximately 1. The catalyst can contain from 0.5% to 20% by
weight of nickel.
[0084] The metal can be present in metallic form or in the form of
a derivative, for example an oxide, halide or oxyhalide. These
derivatives are preferably obtained by activation of the catalytic
metal.
[0085] The support preferably consists of aluminum, for example
alumina, activated alumina or aluminum derivatives, such as
aluminum halides and aluminum oxyhalides, for example described in
the document U.S. Pat. No. 4,902,838, or obtained by the activation
process described above.
[0086] The catalyst can comprise chromium and nickel in an
activated or nonactivated form, on a support which has or has not
been subjected to an activation.
[0087] Reference may be made to the document WO 2009/118628 (in
particular on p. 4, 1. 30-p. 7, 1. 16), to which reference is
expressly made here.
[0088] Another preferred embodiment is based on a mixed catalyst or
mixed preliminary catalyst containing chromium and at least one
cocatalyst chosen from Co, Mn, Mg and Zn salts, preferably Zn
salts. Said cocatalyst is preferably present in a content of 1% to
10% by weight, based on the weight of the catalyst.
[0089] The catalyst and the preliminary catalyst can be identical.
Before its use, the catalyst or the preliminary catalyst is
preferably subjected to an activation with air, oxygen or chlorine
and/or with HF. For example, the catalyst is preferably subjected
to an activation with air or oxygen and HF at a temperature of 100
to 500.degree. C., preferably of 250 to 500.degree. C. and more
particularly of 300 to 400.degree. C. The duration of activation is
preferably from 1 to 200 h and more particularly from 1 to 50 h.
This activation can be followed by a final fluorination activation
stage in the presence of an oxidizing agent, HF and organic
compounds. The HF/organic compounds molar ratio is preferably from
2 to 40 and the oxidizing agent/organic compounds molar ratio is
preferably from 0.04 to 25. The temperature of the final activation
is preferably from 300 to 400.degree. C. and its duration is
preferably from 6 to 100 h.
[0090] According to one embodiment, the stage of reaction of a
compound B in the presence of hydrofluoric acid or the stage of
reaction of a compound A in the presence of hydrofluoric acid is
carried out alternately with a stage of regeneration of the
catalyst or of the preliminary catalyst.
[0091] The reaction in the gas phase in the presence of
hydrofluoric acid of the compound B or of the compound A can be
carried out: [0092] with an HF/compound B or compound A molar ratio
of 3:1 to 150:1, preferably of 4:1 to 125:1 and more particularly
preferably of 5:1 to 100:1; [0093] with a contact time of 3 to 100
s, preferably 4 to 75 s and more particularly 5 to 50 s (volume of
catalyst divided by the total entering stream, adjusted to the
operating temperature and pressure); [0094] at a pressure ranging
from atmospheric pressure to 20 bar, preferably from 2 to 18 bar
and more particularly from 3 to 15 bar; [0095] at a temperature
(temperature of the catalytic bed) of 200 to 450.degree. C.,
preferably of 250 to 400.degree. C. and more particularly of 280 to
380.degree. C.
[0096] The duration of the reaction stage is typically from 10 to
8000 hours, preferably from 50 to 5000 hours and more particularly
preferably from 70 to 1000 hours.
[0097] An oxidizing agent, preferably oxygen, can optionally be
added during the reaction. The oxygen/organic compounds molar ratio
can be from 0.005 to 2, preferably from 0.01 to 1.5. Oxygen can be
introduced in the pure form or in the form of air or of an
oxygen/nitrogen mixture. Oxygen can also be replaced with
chlorine.
[0098] Alternatively, the stage of reaction of the compound B or of
the compound A in the presence of hydrofluoric acid is essentially
carried out in the absence of oxygen and preferably essentially in
the absence of any oxidizing agent.
[0099] According to one embodiment, the stage of regeneration of
the catalyst or of the preliminary catalyst is carried out
alternately with the stage of reaction of a compound B in the
presence of hydrofluoric acid or with the stage of reaction of a
compound A in the presence of hydrofluoric acid.
[0100] In each reactor used for carrying out the reaction of the
compound B or of the compound A in the presence of HF, said
reaction can be alternated with phases of regeneration of the
catalyst. It is possible, for example, to pass from the reaction
phase to the regeneration phase when the conversion of the compound
B falls below a predetermined threshold, for example of 50%. If
need be, beforehand, a transition period consisting in
decompressing the reaction gas phase is provided. It can be
followed by a phase of flushing using an inert gas or else of
placing under vacuum with the aim of completely removing the
reactants present.
[0101] According to a preferred embodiment, the regeneration of the
catalyst or of the preliminary catalyst of the present process can
comprise the treatment of said catalyst with a gaseous stream
containing an oxidant.
[0102] According to one embodiment, the oxidant used is oxygen or
air or an oxygen/nitrogen mixture or chlorine or a
chlorine/nitrogen mixture. When the regeneration stage is carried
out with air or an oxygen/nitrogen mixture, the proportion of
oxygen can be from 5 mol % to approximately 100 mol %, with respect
to the mixture of oxygen plus nitrogen.
[0103] According to another embodiment, the regeneration stage can
be carried out with oxygen or air or an oxygen/nitrogen mixture or
chlorine and HF. Advantageously, the regeneration stream contains
at least 1 mol % of oxygen, with respect to the total regeneration
stream. The proportion of oxygen can be from approximately 2 mol %
to approximately 98 mol %, with respect to the mixture of oxygen
plus HF, and from approximately 20 mol % to approximately 100 mol
%, with respect to the mixture of oxygen plus nitrogen.
[0104] The temperature during the regeneration stage can range from
250 to 500.degree. C., preferably from 300 to 450.degree. C., more
preferably from 350 to 400.degree. C.
[0105] The regeneration stage can be carried out with a contact
time of 1 to 200 s, preferably of 1 to 150 s, more preferably of 5
to 100 s; and for a time of 1 to approximately 1500 hours,
preferably of 2 to 1000 hours, more preferably of 4 to 500 hours,
particularly preferably of 10 to 200 hours, in particular of 15 to
150 hours.
[0106] The regeneration stage can be carried out at a pressure
ranging from atmospheric pressure up to 20 bar.
[0107] According to a preferred embodiment, the temperature during
the regeneration stage can be from approximately 250 to 500.degree.
C., with a contact time of from approximately 1 to 200 s, for a
time of 10 to 200 hours and at a pressure ranging from atmospheric
pressure to 20 bar.
[0108] The regeneration stage makes it possible to recover the
initial activity of the catalyst. Several cycles can thus be linked
together without to a significant extent detrimentally affecting
the activity of the catalyst, which makes it possible to increase
its lifetime.
[0109] On conclusion of the regeneration stage, the reactor can be
placed under vacuum, so as to remove the inert gases and the oxygen
which were introduced, prior to the reintroduction of the organic
materials in the presence of hydrofluoric acid.
[0110] According to a preferred embodiment, the stage of reaction
of a compound B in the presence of hydrofluoric acid is carried out
in one of the three reactors while the stage of reaction of a
compound A in the presence of hydrofluoric acid is carried out in
one of the other two reactors.
[0111] According to a preferred embodiment, a regeneration stage is
carried out in one of the three reactors while a stage of reaction
of a compound B in the presence of hydrofluoric acid is carried out
in one of the other two reactors. Preferably, a regeneration stage
is carried out in one of the three reactors while a stage of
reaction of a compound A in the presence of hydrofluoric acid is
carried out in one of the other two reactors.
[0112] According to a preferred embodiment, said process also
comprises the implementation of a waiting stage during which an
inert gaseous stream feeds one of the three reactors; preferably,
the inert gaseous stream consists of a stream of nitrogen, of
argon, of helium or of a mixture of these. The waiting stage is
preferably carried out before or after the regeneration stage.
[0113] According to a specific embodiment, the process according to
the invention employs: [0114] a stage of reaction of a compound A
in the presence of hydrofluoric acid in one of the three reactors;
[0115] a stage of reaction of a compound B in the presence of
hydrofluoric acid in another of the three reactors; [0116] a stage
of regeneration of the catalyst or of the preliminary catalyst or a
waiting stage in the third reactor.
[0117] According to a favored embodiment, the process according to
the invention simultaneously employs: [0118] a stage of reaction of
a compound B in the presence of hydrofluoric acid in one of the
three reactors; [0119] a stage of reaction of a compound A in the
presence of hydrofluoric acid in another of the three reactors;
[0120] a stage of regeneration of the catalyst or of the
preliminary catalyst or a waiting stage in the third reactor.
[0121] Preferably, the process comprises: [0122] the collecting of
a stream of products on conclusion of the stage of reaction of the
compound B; [0123] the use of said stream of products collected on
conclusion of the stage of reaction of the compound B in order to
carry out the stage of reaction of the compound A in the presence
of hydrofluoric acid; and [0124] the separation of the stream of
products resulting from the stage of reaction of the compound A in
the presence of hydrofluoric acid into a first stream comprising
hydrochloric acid and tetrafluoropropene and a second stream
comprising hydrofluoric acid and the compound B; [0125] optionally,
the collecting of said second stream comprising hydrofluoric acid
and the compound B, and the recycling of this in the stage of
reaction of the compound B in the presence of hydrofluoric acid or
of the stage of reaction of the compound A.
[0126] Alternatively, the process comprises: [0127] the collecting
of a stream of products on conclusion of the stage of reaction of
the compound A; [0128] the use of said stream of products collected
on conclusion of the stage of reaction of the compound A in order
to carry out the stage of reaction of the compound B in the
presence of hydrofluoric acid; and [0129] the separation of the
stream of products resulting from the stage of reaction of the
compound B in the presence of hydrofluoric acid into a first stream
comprising hydrochloric acid and tetrafluoropropene and a second
stream comprising hydrofluoric acid and the compound B; [0130]
optionally, the collecting of said second stream comprising
hydrofluoric acid and the compound B, and the recycling of this in
the stage of reaction of the compound B in the presence of
hydrofluoric acid or of the stage of reaction of the compound
A.
[0131] According to a preferred embodiment, the reactors used in
the present process are made of steel and have an interior surface
covered with an alloy comprising more than 30% by weight of nickel
or with a coating of fluoropolymers type; preferably, the alloy
comprising more than 30% by weight of nickel is an Incolloy.RTM.,
Inconel.RTM., Monel.RTM. or Hastelloy.RTM..
[0132] According to a specific embodiment, the tetrafluoropropene
is 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene.
[0133] "Compound B" is understood to mean an organic compound
comprising one or more carbon atoms. This compound preferably
comprises 3 carbon atoms. This compound B is preferably a propane
or a propene having one or more substituents chosen from F, Cl, I
and Br (preferably from F and Cl). Preferably, the compound B is a
propane or propene comprising at least one fluorine atom, in
particular comprising two, three, four or five fluorine atoms, more
particularly three or five fluorine atoms.
[0134] "Compound A" is understood to mean an organic compound
comprising one or more carbon atoms, preferably 3 carbon atoms. The
compound A is preferably a propane or a propene having one or more
substituents chosen from F, Cl, I and Br (preferably from F and CO.
Preferably, the compound A is a propane or propene comprising at
least one chlorine atom, two, three, four or five chlorine atoms.
Preferably, the compound A has a lower degree of fluorination than
that of the compound B.
[0135] It is understood that "compound B" or "compound A" is also
understood to mean mixtures of compounds.
[0136] The compound B can be chosen from chlorotrifluoropropenes,
pentafluoropropanes, dichlorotrifluoropropanes,
trichlorodifluoropropanes, tetrachlorofluoropropanes,
dichlorodifluoropropenes, trichlorofluoropropenes and a mixture of
these.
[0137] The compound A can be chosen from tetrachloropropenes,
chlorotrifluoropropenes, pentachloropropanes,
dichlorotrifluoropropanes, trichlorodifluoropropanes,
tetrachlorofluoropropanes, dichlorodifluoropropenes,
trichlorofluoropropenes and the mixtures of these.
[0138] Preferably, the compound B can be chosen from the group
consisting of 2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf),
2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db),
1,1,1,2,2-pentafluoropropane (HFC-245cb) and
1-chloro-3,3,3-trifluoropropene (HCFO-1233zd).
[0139] Preferably, the compound A can be chosen from the group
consisting of 2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf),
1,1,1,2,3-pentachloropropane (HCC-240db),
1,1,2,2,3-pentachloropropane (HCC-240aa),
2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db),
1,1,2,3-tetrachloro-1-propene (HCO-1230xa),
2,3,3,3-tetrachloro-1-propene (HCO-1230xf),
1,1,1,3,3-pentachloropropane (HCC-240fa),
1,1,3,3-tetrachloropropene (HCO-1230za), 1,3,3,3-tetrachloropropene
(HCO-1230zd), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd),
1,1,1,3-tetrachloropropane (HCC-250fb), 1,1,3-trichloropropene
(HCO-1240za) and 3,3,3-trichloropropene (HCO-1240zf).
Advantageously, the compound A can be different from the compound
B.
[0140] In particular, the compound B can be selected from the group
consisting of 2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf) and
1,1,1,2,2-pentafluoropropane (HFC-245cb).
[0141] In particular, the compound A can be selected from the group
consisting of 2-chloro-3,3,3-trifluoro-1-propene (HCFO-1233xf),
2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db),
1,1,1,2,3-pentachloropropane (HCC-240db),
1,1,2,2,3-pentachloropropane (HCC-240aa),
1,1,1,3,3-pentachloropropane (HCC-240fa),
1,1,2,3-tetrachloro-1-propene (HCO-1230xa),
2,3,3,3-tetrachloro-1-propene (HCO-1230xf),
1,1,3,3-tetrachloro-1-propene (HCO-1230za) and
1,3,3,3-tetrachloro-1-propene (HCO-1230zd).
[0142] In one embodiment, the compound B is
2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), in order to produce
2,3,3,3-tetrafluoropropene (HFO-1234yf).
[0143] In another embodiment, the compound B is
1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), in order to produce
1,3,3,3-tetrafluoropropene (HFO-1234ze).
[0144] In another embodiment, the compound A is
1,1,1,2,3-pentachloropropane (HCC-240db) or
1,1,2,2,3-pentachloropropane (HCC-240aa) or else a mixture of the
two, in order to produce 2,3,3,3-tetrafluoropropene (HFO-1234y1).
In particular, the compound A is 1,1,1,2,3-pentachloropropane
(HCC-240db) or 1,1,2,2,3-pentachloropropane (HCC-240aa) or else a
mixture of the two; and the compound B is
2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), in order to produce
2,3,3,3-tetrafluoropropene (HFO-1234yf).
[0145] According to yet another embodiment, the compound A is
2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db), in order to
produce 2,3,3,3-tetrafluoropropene (HFO-1234yf). In particular, the
compound A is 2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db) and
the compound B is 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), in
order to produce 2,3,3,3-tetrafluoropropene (HFO-1234yf).
[0146] According to yet another embodiment, the compound A is
1,1,2,3-tetrachloropropene (HCO-1230xa) or
2,3,3,3-tetrachloropropene (HCO-1230xf) or a mixture of these two
compounds, in order to produce 2,3,3,3-tetrafluoropropene
(HFO-1234yf). In particular, the compound A is
1,1,2,3-tetrachloropropene (HCO-1230xa) or
2,3,3,3-tetrachloropropene (HCO-1230xf) or a mixture of these two
compounds; and the compound B is 2-chloro-3,3,3-trifluoropropene
(HCFO-1233xf), in order to produce 2,3,3,3-tetrafluoropropene
(HFO-1234yf).
[0147] According to yet another embodiment, the compound A is
1,1,2,3-tetrachloropropene (HCO-1230xa) or 2,3,3,3
-tetrachloropropene (HCO-1230xf) or 1,1,1,2,3-pentachloropropane
(HCC-240db) or a mixture of two of these or a mixture of the three;
and the compound B is 2-chloro-3,3,3-trifluoropropene
(HCFO-1233xf), in order to produce 2,3,3,3-tetrafluoropropene
(HFO-1234yf).
[0148] According to one embodiment, the compound B is
1,1,1,2,2-pentafluoropropane (HFC-245cb), in order to produce
2,3,3,3-tetrafluoropropene (HFO-1234yf). Preferably, the compound A
is 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and the compound B
is 1,1,1,2,2-pentafluoropropane (HFC-245cb), in order to produce
2,3,3,3-tetrafluoropropene (HFO-1234yf).
[0149] According to another embodiment, the compound A is
1,1,3,3-tetrachloropropene (HCO-1230za) or
1,3,3,3-tetrachloro-1-propene (HCO-1230zd) or a mixture of the two;
and the compound B is 1-chloro-3,3,3-trifluoropropene
(HCFO-1233zd), in order to produce 1,3,3,3-tetrafluoropropene
(HFO-1234ze).
[0150] According to another embodiment, the compound A is
1,1,1,3,3-pentachloropropane (HCC-240fa) and the compound B is
1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), in order to produce
1,3,3,3-tetrafluoropropene (HFO-1234ze).
[0151] According to a preferred embodiment, the regeneration stream
is in the same direction or in the reverse direction, preferably in
the reverse direction, with respect to the direction of
introduction of a reaction stream comprising the compound B and
hydrofluoric acid or the compound A and hydrofluoric acid feeding a
reactor carrying out a stage of reaction of a compound B in the
presence of hydrofluoric acid or a stage of reaction of a compound
A in the presence of hydrofluoric acid. In particular, the
direction of the regeneration stream is alternated at each
regeneration stage.
[0152] According to a second aspect of the present invention, a
plant 1 for the manufacture of tetrafluoropropene. Preferably, the
plant 1 is configured in order to carry out the process according
to the present invention described in detail above.
[0153] The plant comprises three reactors 2a, 2b, 2c for reaction
in the gas phase each comprising a catalytic bed containing a
catalyst or a preliminary catalyst 21a, 21b, 21c. According to a
preferred embodiment, the three reactors 2a, 2b, 2c for reaction in
the gas phase are each configured in order to be fed by: [0154] a
device for feeding with reaction stream 16 comprising a compound B
and hydrofluoric acid; and/or [0155] a device for feeding with
preliminary reaction stream 20 comprising a compound A and
hydrofluoric acid; and/or [0156] a device for feeding with
regeneration stream 11 configured in order to feed the reactor with
a regeneration stream comprising an oxidizing agent; [0157]
optionally, a device for feeding with waiting stream 14 configured
in order to feed the reactor with an inert gaseous stream
comprising an inert gas.
[0158] Preferably, the amount of catalyst or of preliminary
catalyst n in the catalytic bed 21a, 21b, 21c of one of the
reactors 2a, 2b, 2c is from 90% to 110% of the amount of catalyst
or of preliminary catalyst present in the catalytic bed of one of
the other two reactors.
[0159] According to a specific embodiment, the amount of catalyst
or of preliminary catalyst present in the catalytic bed of each
reactor is between 90% and 110% of the amount of catalyst or of
preliminary catalyst present in the catalytic bed of the other two
reactors considered independently of one another, advantageously
between 92% and 108%, preferably between 95% and 105%, in
particular between 98% and 102%.
[0160] Preferably, as explained above with reference to the
process, the amount of catalyst or of preliminary catalyst present
in the catalytic bed 21a, 21b, 21c of each reactor 2a, 2b, 2c is
identical in the three reactors.
[0161] According to a preferred embodiment, the plant is configured
so that, when the first reactor 2a is fed by the device for feeding
with reaction stream 16, the second reactor 2b is fed by the device
for feeding with regeneration stream 11. Preferably, the device for
feeding with regeneration stream 11 is connected at the top and at
the bottom of the reactor. In particular, the plant is configured
so that the device for feeding with regeneration stream 11 feeds
any one of the three reactors at the bottom and at the top
alternately.
[0162] According to a preferred embodiment, the tetrafluoropropene
is 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene. The
compounds A and B are as described above in connection with the
process for the manufacture of tetrafluoropropene.
[0163] The plant can comprise: [0164] a first reactor 2a, a second
reactor 2b and a third reactor 2c; [0165] a first device for
collecting stream of products resulting from the first reactor 18a
connected at the outlet of the latter; [0166] a second device for
collecting stream of products resulting from the second reactor 18b
connected at the outlet of the latter; [0167] a third device for
collecting stream of products resulting from the third reactor 18c
connected at the outlet of the latter; [0168] a first intermediate
collecting device 13 connected to any one of the devices for
collecting stream of products 18a, 18b, 18c and joined to the
device for feeding with preliminary reaction stream 20; [0169] a
second intermediate collecting device 19 connected to any one of
the devices for collecting stream of products 18a, 18b, 18c and
joined to the separation unit 4; [0170] a separation unit 4 fed by
the second intermediate collecting device 19; [0171] a first
collecting pipe 15 and a second collecting pipe 17 which are
connected at the outlet of the separation unit 4, the first
collecting pipe 15 being configured in order to transport a stream
comprising hydrochloric acid and tetrafluoropropene and the second
collecting pipe 17 being configured in order to transport a stream
comprising hydrofluoric acid and compound B; [0172] a device for
feeding with reaction stream 16 configured in order to feed the
first reactor 2a, the second reactor 2b and the third reactor 2c,
this device being itself fed by a device for feeding with
hydrofluoric acid 10 and optionally by the second collecting pipe
17; [0173] a device for feeding with preliminary reaction stream 20
configured in order to feed the first reactor 2a, the second
reactor 2b and the third reactor 2c, this device being itself fed
by a device for feeding with hydrofluoric acid 10 and optionally by
the first intermediate collecting device 13; [0174] a device for
feeding with regeneration stream 11 configured in order to feed the
first reactor 2a, the second reactor 2b and the third reactor 2c;
[0175] a device for collecting stream of gas resulting from the
regeneration 12 of the first reactor 2a, of the second reactor 2b
and of the third reactor 2c.
[0176] Alternatively, the plant can comprise: [0177] a first
reactor 2a, a second reactor 2b and a third reactor 2c; [0178] a
first device for collecting stream of products resulting from the
first reactor 18a connected at the outlet of the latter; [0179] a
second device for collecting stream of products resulting from the
second reactor 18b connected at the outlet of the latter; [0180] a
third device for collecting stream of products resulting from the
third reactor 18c connected at the outlet of the latter; [0181] a
third intermediate collecting device 3 connected to any one of the
devices for collecting stream of products 18a, 18b, 18c and joined
to the device for feeding with reaction stream 16; [0182] a second
intermediate collecting device 19 connected to any one of the
devices for collecting stream of products 18a, 18b, 18c and joined
to the separation unit 4; [0183] a separation unit 4 fed by the
second intermediate collecting device 19; [0184] a first collecting
pipe 15 and a second collecting pipe 17 which are connected at the
outlet of the separation unit 4, the first collecting pipe 15 being
configured in order to transport a stream comprising hydrochloric
acid and tetrafluoropropene and the second collecting pipe 17 being
configured in order to transport a stream comprising hydrofluoric
acid and compound B; [0185] a device for feeding with reaction
stream 16 configured in order to feed the first reactor 2a, the
second reactor 2b and the third reactor 2c, this device being
itself fed by a device for feeding with hydrofluoric acid 10, and
by the third intermediate collecting device 3 and optionally by the
second collecting pipe 17; [0186] a device for feeding with
preliminary reaction stream 20 configured in order to feed the
first reactor 2a, the second reactor 2b and the third reactor 2c,
this device being itself fed by a device for feeding with
hydrofluoric acid 10 and optionally by the second collecting pipe
17; [0187] a device for feeding with regeneration stream 11
configured in order to feed the first reactor 2a, the second
reactor 2b and the third reactor 2c; [0188] a device for collecting
stream of gas resulting from the regeneration 12 of the first
reactor 2a, of the second reactor 2b and of the third reactor
2c.
[0189] Preferably, the reaction stream comprises said compound B
and optionally hydrofluoric acid. The preliminary reaction stream
can comprise said compound A and optionally hydrofluoric acid.
[0190] The plant can also comprise a device for feeding with
waiting stream 14 configured in order to feed the first reactor 2a,
the second reactor 2b and the third reactor 2c with an inert
gaseous stream. Thus, the plant also comprises a device for
collecting an inert gas stream 23 resulting from the first reactor
2a, from the second reactor 2b and from the third reactor 2c.
[0191] The device for feeding with waiting stream 14 and the device
for feeding with regeneration stream 11 can be configured in order
to feed, at the top and at the bottom, any one of the three
reactors 2a, 2b, 2c. This can be carried out by a suitable device,
for example a set of valves 25a, 25b, 25c, 25d as represented in
FIG. 3a and in FIG. 3b.
[0192] The reactors 2a, 2b, 2c are preferably made of steel and
have an interior surface covered with an alloy comprising more than
30% by weight of nickel or with a coating of fluoropolymers type;
preferably, the alloy comprising more than 30% by weight of nickel
is an Incolloy.RTM., Inconel.RTM., Monel.RTM. or
Hastelloy.RTM..
[0193] The plant will be described below in a detailed way in
connection with FIGS. 1a to 4, without being limited thereto. In
the description below, the compound A is, for example,
1,1,1,2,3-pentachloropropane (HCC-240db).
[0194] FIG. 1a illustrates a plant according to an embodiment of
the present invention in which a stage of reaction of a compound A
HCC-240db is carried out in the first reactor 2a. A stream 10
comprising hydrofluoric acid also feeds the reactor 2a in order to
make possible the reaction between the HCC-240db and HF via the
device for feeding with preliminary reaction stream 20. The valve 7
is configured for this purpose. The first reactor 2a comprises the
catalytic bed 21a. The first device for collecting stream of
products 18a resulting from the first reactor 2a and connected at
the outlet of the latter feeds the second intermediate collecting
device 19, itself connected to the separation unit 4. The first
device for collecting stream of products 18a and the second
intermediate collecting device 19 comprise in particular a stream
of products comprising at least HCFO-1233xf, HF and HCl, and
optionally HFO-1234yf and HFC-245cb. The latter stream is
separated, at the separation unit 4, into a first stream comprising
HCl and optionally HFO-1234yf in the first collecting pipe 15 and,
in the second collecting pipe 17, into a second stream comprising
HCFO-1233xf, HF and possibly HFC-245cb. The second collecting pipe
17 is connected to the device for feeding with reaction stream 16,
itself fed with hydrofluoric acid 10. The device for feeding with
reaction stream 16 feeds the third reactor 2c comprising a
catalytic bed 21c. In this third reactor, the compound B, in this
instance HCFO-1233xf, is subjected to a catalytic reaction in order
to form a stream of products comprising HFO-1234yf and HFC-245cb
which is collected at the outlet of the reactor by the third device
for collecting stream of products 18c. The third device for
collecting stream of products 18c resulting from the third reactor
feeds the first intermediate collecting device 13 joined to the
device for feeding with preliminary reaction stream 20. The second
reactor 2b comprising the catalytic bed 21b is in the regeneration
phase. The reactor 2b is thus fed with a regeneration stream
conveyed by the device for feeding with regeneration stream 11 via
the valve 8 configured for this purpose. The second device for
collecting the stream of the products 18b resulting from the second
reactor is connected to the device for collecting stream of gas
resulting from the regeneration 12 via a valve 6 configured for
this purpose. The process is carried out continuously.
[0195] FIG. 1b illustrates a plant according to an embodiment of
the present invention in which the direction of the regeneration
stream is modified with respect to that of the embodiment
illustrated in FIG. 1a. To this end, the regeneration stream feeds
the second reactor 2b by the top of the reactor. The direction of
the regeneration stream is thus reversed with respect to the
direction of introduction of the reaction stream and of the
preliminary reaction stream in, respectively, the first reactor 2a
and the third reactor 2c.
[0196] FIG. 2a illustrates a plant according to an embodiment of
the present invention in which a reaction between the compound B,
HCFO-1233xf and HF is carried out in the first reactor 2a, a
reaction between HCC-240db and HF is carried out in the second
reactor 2b and a regeneration of the catalyst is carried out in the
third reactor 2c. The device for feeding with preliminary stream 20
is fed with hydrofluoric acid 10 and HCC-240db and by the first
intermediate collecting device 13. The device for feeding with
preliminary stream 20 is connected to the second reactor 2b; the
valve 8 is configured for this purpose. The second device for
collecting the stream of products 18b resulting from the second
reactor 2b is joined to the second intermediate collecting device
19, the latter being connected to the separation unit 4. The second
collecting pipe 17 feeds the device for feeding with reaction
stream 16 feeding the first reactor 2a. The first device for
collecting the stream of products 18a resulting from the first
reactor 2a is configured in order to feed the first intermediate
collecting device 13 via the valve 5. The third reactor 2c is in
the regeneration phase. The latter is thus fed with regeneration
stream by the device for feeding with regeneration stream 11 via
the valve 22 configured for this purpose. The third device for
collecting stream of products 18c from the third reactor is
connected to the device for collecting the stream of gas resulting
from the regeneration 12 via the valve 24.
[0197] With respect to FIG. 2a, FIG. 2b illustrates a plant
according to an embodiment of the present invention in which the
regeneration stream feeds the third reactor 2c by the top of the
latter. The direction of the regeneration stream is thus reversed
with respect to the stream of the reaction mixture or of the
preliminary mixture which respectively feed the second reactor 2b
and the first reactor 2a by the bottom of the reactor.
[0198] With respect to FIG. 2b, FIG. 2c illustrates a plant
according to an embodiment of the present invention in which the
third reactor is fed with an inert gas stream instead of a
regeneration stream. The third reactor 2c is thus connected to the
device for feeding with waiting stream 14 comprising an inert gas.
The device for collecting stream of products 18c from the third
reactor is connected to the device for collecting the inert gas
stream 23.
[0199] With respect to FIG. 1a, FIG. 3a illustrates a plant
according to an embodiment of the present invention in which the
reactors can be fed with a regeneration stream at the top and at
the bottom of the reactor alternately. The valves 25a, 25b, 25c and
25d are configured in order to make it possible to feed the third
reactor 2c either by the top or the bottom of the latter with a
regeneration stream resulting from the device for feeding with
regeneration stream 11 according to the same principle as that
described in detail for FIG. 1a. The same principle can be applied
with the stream resulting from the device for feeding with inert
gas 14.
[0200] With respect to FIG. 3a, FIG. 3b illustrates a plant
according to an embodiment of the present invention in which the
first reactor 2a is in the regeneration phase instead of the third
reactor 2c.
[0201] FIG. 4 illustrates a plant according to another embodiment
of the present invention. The plant 1 comprises a third
intermediate collecting device 3 feeding the device for feeding
with reaction mixture 16 instead of the first intermediate
collecting device 13. The third reactor 2c is in the regeneration
phase, as explained above in FIG. 2b. The second reactor 2b is fed
by the device for feeding with preliminary reaction stream 20. The
second device for collecting stream of products 18b at the outlet
of the second reactor 2b is connected to the third intermediate
collecting device 3. The latter feeds the device for feeding with
reaction stream 16. The first reactor 2a is fed by the device for
feeding with reaction stream 16. The first device for collecting
stream of products 18a at the outlet of the first reactor 2a is
joined to the second intermediate collecting device 19. The stream
of products resulting from the first reactor 2a comprises
HCFO-1233xf, HCC-240db, HFO-1234yf, HF and HCl. This stream is
separated in the separation unit 4, as explained above. The second
collecting pipe 17 can feed either the device for feeding with
reaction stream 16 or the device for feeding with preliminary
reaction stream 20 via the valve 26, which can be configured for
either alternative.
[0202] The invention makes it possible to optimize the manufacture
of tetrafluoropropene (HFO-1234yf or HFO-1234ze) by alternating the
cycles of regeneration and of manufacture of the tetrafluoropropene
with three reactors comprising the same amount of catalyst. The
invention also makes it possible to improve the regeneration stage
by making it possible to carry out the latter alternately by the
bottom or the top of the reactor in order to prevent the
accumulation of coke in the reactor.
* * * * *