U.S. patent application number 16/836977 was filed with the patent office on 2020-07-16 for method and plant 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 | 20200223774 16/836977 |
Document ID | / |
Family ID | 56684041 |
Filed Date | 2020-07-16 |
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United States Patent
Application |
20200223774 |
Kind Code |
A1 |
DEUR-BERT; Dominique ; et
al. |
July 16, 2020 |
METHOD AND PLANT FOR PRODUCING TETRAFLUOROPROPENE
Abstract
A plant for the manufacture of tetrafluoropropene comprises
three reactors for reaction in the gas phase comprising a catalyst
bed. The first and second reactor are each configured in order to
be fed in turn by a device for feeding with a reaction stream
comprising a compound B and hydrofluoric acid; and a device for
feeding with a regeneration stream configured in order to feed the
reactor with a regeneration stream comprising an oxidizing agent.
The third reactor is configured in order to be fed in turn by a
device for feeding with a reaction stream comprising a compound A
and hydrofluoric acid; said compound A being different from said
compound B; and a device for feeding with a regeneration stream
configured in order to feed the reactor with a regeneration stream
comprising an oxidizing agent.
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: |
56684041 |
Appl. No.: |
16/836977 |
Filed: |
April 1, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16099208 |
Nov 6, 2018 |
10640438 |
|
|
PCT/FR2017/051187 |
May 17, 2017 |
|
|
|
16836977 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 2208/00371
20130101; B01J 19/02 20130101; B01J 2219/0286 20130101; B01J
2219/0295 20130101; C07C 21/18 20130101; B01J 8/0457 20130101; B01J
38/12 20130101; B01J 8/0492 20130101; C07C 17/206 20130101; C07C
17/206 20130101; C07C 21/18 20130101 |
International
Class: |
C07C 17/20 20060101
C07C017/20; B01J 8/04 20060101 B01J008/04; B01J 19/02 20060101
B01J019/02; B01J 38/12 20060101 B01J038/12; C07C 21/18 20060101
C07C021/18 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 2016 |
FR |
1654445 |
Claims
1. A plant for the manufacture of tetrafluoropropene comprising
three reactors for reaction in the gas phase comprising a catalyst
bed, the first reactor and the second reactor for reaction in the
gas phase being each configured in order to be fed in turn by: a
device for feeding with a reaction stream comprising a compound B
and hydrofluoric acid; and a device for feeding with a regeneration
stream configured in order to feed the reactor with a regeneration
stream comprising an oxidizing agent; and the third reactor for
reaction in the gas phase being configured in order to be fed in
turn by: a device for feeding with a reaction stream comprising a
compound A and hydrofluoric acid, and optionally an intermediate
collecting device connected at the outlet of the first reactor or
of the second reactor; said compound A being different from said
compound B; and a device for feeding with a regeneration stream
configured in order to feed the reactor with a regeneration stream
comprising an oxidizing agent.
2. The plant as claimed in claim 1, configured so that, when the
first reactor is fed by the device for feeding with reaction
stream, the second reactor is fed by the device for feeding with a
regeneration stream.
3. The plant as claimed in claim 1, in which the device for feeding
with the regeneration stream is connected at the top and at the
bottom of the reactor.
4. The plant as claimed in claim 1, configured so that the device
for feeding with the regeneration stream feeds any one of the three
reactors at the bottom and at the top alternately.
5. The plant as claimed in claim 1, wherein the tetrafluoropropene
comprises 2,3,3,3-tetrafluoropropene or
1,3,3,3-tetrafluoropropene.
6. The plant as claimed in claim 1, wherein the compound A is
selected from the group consisting of tetrachloropropenes,
chlorotrifluoropropenes, pentachloropropanes,
dichlorotrifluoropropanes, trichlorodifluoropropanes,
tetrachlorofluoropropanes, dichlorodifluoropropenes,
trichlorofluoropropenes and the mixtures of these; and the compound
B is selected from the group consisting of chlorotrifluoropropenes,
pentafluoropropanes, dichlorotrifluoropropanes,
trichlorodifluoropropanes, tetrachlorofluoropropanes,
dichlorodifluoropropenes, trichlorofluoropropenes and the mixtures
of these.
7. The plant as claimed in claim 1, comprising: a first reactor; a
second reactor; a third reactor; a device for collecting a stream
of products resulting from the third reactor connected at the
outlet of the third reactor; a separation unit fed by the device
for collecting the stream of products resulting from the third
reactor; 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 the compound B; an intermediate
collecting device connected at the outlet of the first reactor or
of the second reactor; a first device for feeding the third reactor
configured in order to feed the third reactor, this device being
itself fed by the device for feeding with preliminary reaction
mixture and optionally by the intermediate collecting device; a
second device for feeding with reaction medium configured in order
to alternately feed the second reactor and the first reactor, this
device being itself fed by the second collecting pipe and
optionally by a device for feeding with hydrofluoric acid; a device
for feeding with the regeneration stream configured in order to
feed the first reactor and the second reactor; a device for feeding
with the regeneration stream configured in order to feed the third
reactor; a device for collecting a stream of gas resulting from the
regeneration of the first reactor and of the second reactor; and a
device for collecting a stream of gas resulting from the
regeneration of the third reactor.
8. The plant as claimed in claim 1, comprising: a first reactor; a
second reactor; a third reactor; a device for collecting a stream
of products connected at the outlet of the first reactor and of the
second reactor; a separation unit fed by the device for collecting
stream of products; 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 the compound B; an
intermediate collecting device connected at the outlet of the third
reactor; a first device for feeding with a reaction medium
configured in order to feed the third reactor, this device being
itself fed by the device for feeding with preliminary reaction
mixture and optionally by the second collecting pipe; a second
device for feeding with a reaction medium configured in order to
feed the first reactor or second reactor, this device being itself
fed by the intermediate collecting device and optionally by a
device for feeding with hydrofluoric acid; a device for feeding
with a regeneration stream configured in order to feed the first
reactor and the second reactor; a device for feeding with a
regeneration stream configured in order to feed the third reactor;
a device for collecting a stream of gas resulting from the
regeneration of the first reactor and of the second reactor; and a
device for collecting a stream of gas resulting from the
regeneration of the third reactor.
9. 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 of U.S. patent application
Ser. No. 16/099,208, filed on Nov. 6, 2018, which is a National
Stage application of International Patent Application No.
PCT/FR2017/051187, filed on May 17, 2017, which claims the benefit
of French Patent Application No. 1654445, 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] The present invention relates, according to a first aspect,
to a process for the manufacture of tetrafluoropropene employing
three reactors and comprising the stages of: [0016] carrying out,
in the first and the second reactor, 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;
alternately with a stage of regeneration of the catalyst by
bringing the latter into contact with a regeneration stream
comprising an oxidizing agent, [0017] carrying out, in the third
reactor, a preliminary stage of manufacture of the compound B,
which is preferably a preliminary stage of reaction in the gas
phase of a compound A in the presence of hydrofluoric acid and of a
preliminary catalyst, said compound A being different from said
compound B, alternately with a stage of regeneration of the
preliminary catalyst with a regeneration stream comprising an
oxidizing agent,
[0018] characterized in that: [0019] the stage of regeneration of
the preliminary catalyst in the third reactor is carried out in the
absence of stage of reaction of the compound B in the presence of
hydrofluoric acid in said first and second reactors.
[0020] According to one embodiment, the process comprises: [0021]
the collecting of a stream of products on conclusion of the
preliminary stage of manufacture of the compound B; [0022] the use
of said stream of products in order to carry out the stage of
reaction of the compound B in the presence of hydrofluoric acid;
and [0023] 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; [0024] 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 preliminary stage of
manufacture of the compound B.
[0025] According to one embodiment, the stage of regeneration of
the preliminary catalyst in the third reactor is carried out
simultaneously with the stage of regeneration of the catalyst in
the first reactor or the second reactor or both; or in the absence
of stage of regeneration of the catalyst in the first reactor or
the second reactor or both. In this case, the first reactor and/or
the second reactor can be in the regeneration phase or in the
waiting phase, that is to say a phase during which no stream
circulates or only a stream consisting of an inert gas.
[0026] According to one embodiment, in the first reactor and the
second reactor, the stage of reaction of a compound B in the
presence of hydrofluoric acid is carried out alternately with the
regeneration stage.
[0027] According to one 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..
[0028] According to a preferred embodiment, the tetrafluoropropene
is 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene.
[0029] 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 (HFCO-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).
[0030] 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 into the first reactor or the second reactor of a
reaction stream comprising the compound B and hydrofluoric
acid.
[0031] According to a preferred embodiment, the direction of the
regeneration stream is alternated at each regeneration stage.
[0032] The invention also relates to a plant for the manufacture of
tetrafluoropropene, comprising three reactors for reaction in the
gas phase comprising a catalyst bed, [0033] the first reactor and
the second reactor for reaction in the gas phase being each
configured in order to be fed in turn by: [0034] a device for
feeding with reaction stream comprising a compound B and
hydrofluoric acid; and [0035] a device for feeding with
regeneration stream configured in order to feed the reactor with a
regeneration stream comprising an oxidizing agent; and [0036] the
third reactor for reaction in the gas phase being configured in
order to be fed in turn by: [0037] a device for feeding with
reaction stream comprising a compound A and hydrofluoric acid, and
optionally an intermediate collecting device connected at the
outlet of the first reactor or of the second reactor; said compound
A being different from said compound B; and [0038] a device for
feeding with regeneration stream configured in order to feed the
reactor with a regeneration stream comprising an oxidizing
agent.
[0039] According to one embodiment, the plant is configured so
that, when the first reactor is fed by the device for feeding with
reaction stream, the second reactor is fed by the device for
feeding with regeneration stream.
[0040] According to one embodiment, the device for feeding with
regeneration stream is connected at the top and at the bottom of
the reactor.
[0041] According to one embodiment, the plant is configured so that
the system for feeding with regeneration stream feeds any one of
the three reactors at the bottom and at the top alternately.
[0042] According to a preferred embodiment, the tetrafluoropropene
is 2,3,3,3-tetrafluoropropene or the tetrafluoropropene is
1,3,3,3-tetrafluoropropene.
[0043] 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 (HFCO-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).
[0044] According to a preferred embodiment, the plant comprises:
[0045] a first reactor; [0046] a second reactor; [0047] a third
reactor; [0048] a device for collecting stream of products
resulting from the third reactor connected at the outlet of the
third reactor; [0049] a separation unit fed by the device for
collecting stream of products resulting from the third reactor;
[0050] 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 the compound B; [0051] an
intermediate collecting device connected at the outlet of the first
reactor and/or of the second reactor; [0052] a first device for
feeding the third reactor configured in order to feed the third
reactor, this device being itself fed by the device for feeding
with preliminary reaction mixture and optionally by the
intermediate collecting device; [0053] a second device for feeding
with reaction medium configured in order to alternately feed the
second reactor and the first reactor, this device being itself fed
by the second collecting pipe and optionally by a device for
feeding with hydrofluoric acid; [0054] a device for feeding with
regeneration stream configured in order to feed the first reactor
and the second reactor; [0055] a device for feeding with
regeneration stream configured in order to feed the third reactor;
[0056] a device for collecting stream of gas resulting from the
regeneration of the first reactor and of the second reactor; and
[0057] a device for collecting stream of gas resulting from the
regeneration of the third reactor.
[0058] According to a preferred embodiment, the plant comprises:
[0059] a first reactor; [0060] a second reactor; [0061] a third
reactor; [0062] a device for collecting stream of products
connected at the outlet of the first reactor and of the second
reactor; [0063] a separation unit fed by the device for collecting
stream of products; [0064] 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 the
compound B; [0065] an intermediate collecting device connected at
the outlet of the third reactor; [0066] a first device for feeding
the third reactor configured in order to feed the third reactor,
this device being itself fed by the device for feeding with
preliminary reaction mixture and optionally by the second
collecting pipe; [0067] a second device for feeding with reaction
medium configured in order to feed the first reactor or the second
reactor, this device being itself fed by the intermediate
collecting device and optionally by a device for feeding with
hydrofluoric acid; [0068] a device for feeding with regeneration
stream configured in order to feed the first reactor and the second
reactor; [0069] a device for feeding with regeneration stream
configured in order to feed the third reactor; [0070] a device for
collecting stream of gas resulting from the regeneration of the
first reactor and of the second reactor; and [0071] a device for
collecting stream of gas resulting from the regeneration of the
third reactor.
[0072] According to a preferred embodiment, the reactors of the
plant 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..
[0073] The present invention makes it possible to overcome the
disadvantages of the state of the art. It more particularly
provides a process for the manufacture of HFO-1234 (and in
particular of HFO-1234yf) which has a high yield and which provides
the desired product in a high degree of purity, while being more
economical.
[0074] This is accomplished by virtue of the discovery by the
present inventors that the regeneration stage can be optimized,
without the lifetime of the catalyst being visibly affected over a
predetermined period. In addition, some reaction stages can be
carried out essentially in the absence of oxidizing agent. An
advantage resulting therefrom is that a gaseous stream of HFO-1234
of a higher purity is obtained as it is obtained essentially in the
absence of oxygen during the reaction. In addition, the use of
reactors, only the interior surface of which is in an alloy as
defined in the present invention, renders the process more viable
economically while maintaining a high resistance to corrosion.
BRIEF DESCRIPTION OF THE FIGURES
[0075] FIGS. 1a, 1b and 1c diagrammatically represent an embodiment
of a plant according to the invention with three reactors for
catalytic reaction in different operating configurations.
[0076] FIGS. 2a, 2b, 2c, 2d and 2e diagrammatically represent an
embodiment of a plant according to the invention with three
reactors, the third of which is in regeneration mode, in three
different configurations.
[0077] FIGS. 3a, 3b and 3c 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 three different
configurations.
[0078] FIGS. 4a, 4b and 4c 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 and a separation unit
connected to the outlet of the first and of the second reactors, in
three different configurations.
DETAILED DESCRIPTION OF THE INVENTION
[0079] 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.
[0080] According to a first aspect, the present invention provides
a process for the manufacture of tetrafluoropropene. Said process
for the manufacture of tetrafluoropropene employs three reactors.
The process according to the present invention comprises in
particular a stage of carrying out, in the first reactor and the
second reactor, at least one stage of reaction in the gas phase of
a compound B in the presence of hydrofluoric acid and of a
catalyst; alternately with a stage of regeneration of the catalyst
by bringing the latter into contact with a regeneration stream
comprising an oxidizing agent. Said process can also comprise a
stage of carrying out, in the third reactor, a preliminary stage of
manufacture of the compound B, which is preferably a preliminary
stage of reaction in the gas phase of a compound A in the presence
of hydrofluoric acid and of a preliminary catalyst, said compound A
being different from said compound B, alternately with a stage of
regeneration of the preliminary catalyst with a regeneration stream
comprising an oxidizing agent. In addition, in the present process,
the stage of regeneration of the preliminary catalyst in the third
reactor can be carried out in the absence of stage of reaction of
the compound B in the presence of hydrofluoric acid in said first
and second reactors.
[0081] Thus, according to one embodiment, said process for the
manufacture of tetrafluoropropene in the three reactors comprises
the stages of: [0082] carrying out, in the first and the second
reactor, 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; alternately with a stage
of regeneration of the catalyst by bringing the latter into contact
with a regeneration stream comprising an oxidizing agent, [0083]
carrying out, in the third reactor, a preliminary stage of
manufacture of the compound B, which is preferably a preliminary
stage of reaction in the gas phase of a compound A in the presence
of hydrofluoric acid and of a preliminary catalyst, said compound A
being different from said compound B, alternately with a stage of
regeneration of the preliminary catalyst with a regeneration stream
comprising an oxidizing agent,
[0084] characterized in that: [0085] the stage of regeneration of
the preliminary catalyst in the third reactor being carried out in
the absence of stage of reaction of the compound B in the presence
of hydrofluoric acid in said first and second reactors.
[0086] According to a preferred embodiment, when the third reactor
is in the regeneration phase, that is to say that the stage of
regeneration of the preliminary catalyst is carried out in this
third reactor, the first reactor and the second reactor are,
independently of one another, either in the phase of regeneration
of the catalyst or in the waiting phase, during which no flow
circulates or a flow consisting of an inert gas, such as nitrogen,
argon or helium, circulates in the reactor under consideration or
the reactor under consideration is placed under vacuum.
[0087] "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.
[0088] "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
Cl). 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.
[0089] It is understood that "compound B" or "compound A" is also
understood to mean mixtures of compounds.
[0090] The compound B can be chosen from chlorotrifluoropropenes,
pentafluoropropanes, dichlorotrifluoropropanes,
trichlorodifluoropropanes, tetrachlorofluoropropanes,
dichlorodifluoropropenes, trichlorofluoropropenes and a mixture of
these.
[0091] The compound A can be chosen from tetrachloropropenes,
chlorotrifluoropropenes, pentachloropropanes,
dichlorotrifluoropropanes, trichlorodifluoropropanes,
tetrachlorofluoropropanes, dichlorodifluoropropenes,
trichlorofluoropropenes and the mixtures of these.
[0092] 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).
[0093] 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 used in the third reactor can be
different from the compound B used in the first or the second
reactor.
[0094] 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).
[0095] In particular, the compound A can be selected from the group
consisting of 2-chloro-3,3,3-trifluoro-1-propene (HFCO-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).
[0096] 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).
[0097] 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).
[0098] 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-1234yf).
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).
[0099] 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).
[0100] 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).
[0101] 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).
[0102] 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).
[0103] 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).
[0104] 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).
[0105] The conversion of the compound B to give HFO-1234 can be a
direct conversion or an indirect conversion (that is to say,
involving an intermediate product).
[0106] The reaction of the compound B to give HFO-1234 is carried
out in two reactors for reaction in the gas phase comprising a
catalyst bed. The reaction of the compound A to give compound B is
carried out in a reactor in the gas phase comprising a preliminary
catalyst bed. Said catalyst used in the first and the second
reactor can be identical to the preliminary catalyst used in the
third reactor.
[0107] The catalyst or the 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).
[0108] 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.
[0109] 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.
[0110] The catalyst is more particularly preferably chromium-based
and it is more particularly a mixed catalyst comprising
chromium.
[0111] 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.
[0112] 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.
[0113] The support is preferably formed with 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.
[0114] 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.
[0115] 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.
[0116] 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.
[0117] 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.
[0118] The reaction in the gas phase in the presence of
hydrofluoric acid with the compound B or the compound A can be
carried out: [0119] 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; [0120] 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); [0121] at a pressure ranging
from atmospheric pressure to 20 bar, preferably from 2 to 18 bar
and more particularly from 3 to 15 bar; [0122] at a temperature
(temperature of the catalyst bed) of 200 to 450.degree. C.,
preferably of 250 to 400.degree. C. and more particularly of 280 to
380.degree. C.
[0123] 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.
[0124] 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.
[0125] 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.
[0126] According to a specific embodiment, said process also
comprises: [0127] the collecting of a stream of products on
conclusion of the preliminary stage of manufacture of the compound
B; [0128] the use of said stream of products 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 preliminary stage of manufacture of the compound B.
[0131] According to another specific embodiment, said process also
comprises: [0132] the collecting of a stream of products on
conclusion of the stage of reaction of the compound B in the
presence of hydrofluoric acid; [0133] the use of said stream of
products in order to carry out the stage of reaction of the
compound A in the presence of hydrofluoric acid in order to form a
stream of products in the third reactor; [0134] the separation of
the stream of products thus obtained in the third reactor into a
first stream comprising hydrochloric acid and tetrafluoropropene
and a second stream comprising hydrofluoric acid and the compound
B; and [0135] 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 in the first reactor or the second
reactor.
[0136] The separation of the streams of products resulting
respectively from the stage of reaction of the compound A with HF
or from the stage of reaction of the compound B with HF can be
carried out by a separation unit which can be a distillation column
or any other device capable of separating, on the one hand,
hydrochloric acid and tetrafluoropropene and, on the other hand,
hydrofluoric acid and the compound B.
[0137] In each reactor used for carrying out the reaction of the
compound B or of the compound A with 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.
[0138] 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.
[0139] According to one embodiment, the oxidant used in the
regeneration stage 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.
[0140] 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.
[0141] 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.
[0142] 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.
[0143] The regeneration stage can be carried out at a pressure
ranging from atmospheric pressure up to 20 bar.
[0144] 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 approximately 1 to 200 s, for a time of
10 to 200 hours and at a pressure ranging from atmospheric pressure
to 20 bar.
[0145] 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.
[0146] On conclusion of the regeneration stage, the reactor can be
placed under vacuum, so as to remove the inert gases and the oxygen
introduced, prior to the reintroduction of the organic materials in
the presence of hydrofluoric acid.
[0147] Preferably, the stage of regeneration of the preliminary
catalyst in the third reactor is carried out simultaneously with
the stage of regeneration of the catalyst in the first reactor or
the second reactor or both; or in the absence of stage of
regeneration of the catalyst.
[0148] Preferably, in the first and the second reactor, the
reaction stage as described above is carried out alternately with
the regeneration stage as described above.
[0149] According to a specific embodiment, the reaction and
regeneration streams can be in the same direction or the reverse
direction; preferably, the reaction and regeneration streams are
reversed. In particular, the direction of the regeneration stream
is alternated at each regeneration stage. Thus, during a first
regeneration phase, the reaction and regeneration streams can be in
the same direction and then, in a second regeneration phase, the
reaction and regeneration streams can be reversed.
[0150] According to a specific embodiment, the three reactors used
in the present process can be 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 can be an
Incolloy.RTM., Inconel.RTM., Monel.RTM. or Hastelloy.RTM..
[0151] According to a second aspect of the present invention, a
plant 1 is provided. The plant 1 for the manufacture of
tetrafluoropropene comprises three reactors 2a, 2b and 3 for
reaction in the gas phase and comprises a catalyst bed 21a, 21b or
21c.
[0152] In addition, the first reactor 2a and the second reactor 2b
for reaction in the gas phase are each configured in order to be
fed in turn by: [0153] a device for feeding with reaction stream 16
comprising a compound B and hydrofluoric acid; and [0154] a device
for feeding with regeneration stream 11 configured in order to feed
the reactor with a regeneration stream comprising an oxidizing
agent.
[0155] Furthermore, the third reactor 3 for reaction in the gas
phase can be configured in order to be fed in turn by: [0156] a
device for feeding with reaction stream 13 comprising a compound A
and hydrofluoric acid, and optionally an intermediate collecting
device 19 connected at the outlet of the first reactor 2a or of the
second reactor 2b; said compound A being different from said
compound B; and [0157] a device for feeding with regeneration
stream 14 configured in order to feed the reactor with a
regeneration stream comprising an oxidizing agent.
[0158] As described above in connection with the process, the
reaction stream 16 or 13 can be essentially devoid of oxygen and
preferably of any oxidizing agent. On the other hand, the
regeneration stream 11 or 14 can contain at least 1 mol % of
oxygen, with respect to the total regeneration stream.
[0159] The plant can be 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. Both a device for collecting stream of
products resulting from the reaction and a device for collecting
stream of gas resulting from the regeneration are connected at the
outlet of the reactors 2a and 2b. Device for collecting or device
for feeding is understood to mean a single pipe or an assembly of
several pipes.
[0160] A device of inlet valves 7, 8 and a device of outlet valves
5, 6 are provided in order to make it possible to switch between
the devices for feeding with reaction stream 16 or with
regeneration stream 11 and the respective devices for collecting 12
and 19 of the first reactor 2a and of the second reactor 2b.
[0161] Preferably, the device for feeding with regeneration stream
11 or 14 is connected at the top and at the bottom of the reactor
2a, 2b or 3. This can, for example, be carried out by a device for
regulating the regeneration stream forming an integral part of the
device for feeding with regeneration stream 11, 14. Said device for
regulating the regeneration stream can comprise a plurality of
pipes and at least two regulating valves 25, 25' or 24, 24', as
illustrated, for example, in FIG. 3a.
[0162] Preferably, the plant 1 is configured so that each of the
devices for feeding with regeneration stream 11 or 14 respectively
feeds the first reactor 2a and the second reactor 2b or the third
reactor 3 at the bottom and at the top alternately. The
configuration of the valves 25, 25' or 24, 24' of the device for
regulating the regeneration stream makes it possible to easily
regulate the regeneration streams 11 ou 14 in order to alternate a
regeneration of a reactor at the top and a regeneration of a
reactor at the bottom.
[0163] According to another embodiment, the first reactor 2a, the
second reactor 2b and/or the third reactor 3 can be regenerated in
series, that is to say that the gas stream resulting from the
regeneration of one of the reactors 2a or 2b is conveyed to the
other reactor 2a or 2b or the third reactor 3 and is used for the
regeneration of the catalyst present in the latter.
[0164] The plant 1 is suitable for the manufacture of
tetrafluoropropene; advantageously, the tetrafluoropropene is
2,3,3,3-tetrafluoropropene or the tetrafluoropropene is
1,3,3,3-tetrafluoropropene. The compounds A and B are as described
above in connection with the process for the manufacture of
tetrafluoropropene.
[0165] According to a preferred embodiment, the plant 1 comprises:
[0166] a first reactor 2a; [0167] a second reactor 2b; [0168] a
third reactor 3; [0169] a device for collecting stream of products
resulting from the third reactor 18 connected at the outlet of the
third reactor 3; [0170] a separation unit 4 fed by the device for
collecting stream of products resulting from the third reactor 18;
[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 the compound B; [0172] an
intermediate collecting device 19 connected at the outlet of the
first reactor 2a or of the second reactor 2b; [0173] a first device
for feeding the third reactor 20 configured in order to feed the
third reactor 3, this device being itself fed by the device for
feeding with preliminary reaction mixture 13 and optionally by the
intermediate collecting device 19; [0174] a second device for
feeding with reaction medium 16 configured in order to alternately
feed the second reactor 2b and the first reactor 2a, this device
being itself fed by the second collecting pipe 17 and optionally by
a device for feeding with hydrofluoric acid 10; [0175] a device for
feeding with regeneration stream 11 configured in order to feed the
first reactor 2a and/or the second reactor 2b; [0176] a device for
feeding with regeneration stream 14 configured in order to feed the
third reactor 3; [0177] a first device for collecting stream of gas
resulting from the regeneration of the first reactor and/or of the
second reactor 12; and [0178] a second device for collecting stream
of gas resulting from the regeneration of the third reactor
12'.
[0179] According to an alternative embodiment, when the third
reactor 3 is in the regeneration phase, the device for feeding the
third reactor 20 is configured in order to feed the third reactor 3
with a regeneration stream comprising an oxidizing agent resulting
from the device for feeding with regeneration stream 14.
[0180] Alternatively, the plant can comprise: [0181] a first
reactor 2a; [0182] a second reactor 2b; [0183] a third reactor 3;
[0184] a device for collecting stream of products 19 connected at
the outlet of the first reactor 2a and of the second reactor 2b;
[0185] a separation unit 4 fed by the device for collecting stream
of products 19 resulting from the first reactor 2a or from the
second reactor 2b; [0186] 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 the compound B; [0187] an intermediate collecting device
18 connected at the outlet of the third reactor 3; [0188] a first
device for feeding the third reactor 20 configured in order to feed
the third reactor 3, this device being itself fed by the device for
feeding with preliminary reaction mixture 13 and optionally by the
second collecting pipe 17; [0189] a second device for feeding with
reaction medium 16 configured in order to feed the first reactor 2a
or the second reactor 2b, this device being itself fed by the
intermediate collecting device 18 and optionally by a device for
feeding with hydrofluoric acid 10; [0190] a device for feeding with
regeneration stream 11 configured in order to feed the first
reactor 2a and/or the second reactor 2b; [0191] a device for
feeding with regeneration stream 14 configured in order to feed the
third reactor 3; [0192] a first device for collecting stream of gas
resulting from the regeneration of the first reactor and/or of the
second reactor 12; and [0193] a device for collecting stream of gas
resulting from the regeneration of the third reactor 12'.
[0194] According to an alternative embodiment, when the third
reactor 3 is in the regeneration phase, the device for feeding the
third reactor 20 is configured in order to feed the third reactor 3
with a regeneration stream comprising an oxidizing agent resulting
from the device for feeding with regeneration stream 14.
[0195] According to an alternative embodiment, the second
collecting pipe 17 can feed the device for feeding with reaction
medium 16 configured in order to feed the first reactor 2a or the
second reactor 2b instead of feeding the device for feeding the
third reader 20 configured in order to feed the third reactor
3.
[0196] According to an alternative embodiment, the device for
feeding with regeneration stream configured in order to feed the
first reactor 2a and the second reactor 2b is common to the device
for feeding with regeneration stream configured in order to feed
the third reactor 3, that is to say that a single device for
feeding with regeneration stream is used to feed the three
reactors. The device for feeding with regeneration stream is then
configured for this purpose.
[0197] Advantageously, the reactors used for the manufacture of
tetrafluoropropene 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..
[0198] The plant will be described below in a detailed away in
connection with FIGS. 1a to 4c, without being limited thereto.
[0199] FIG. 1a illustrates a plant according to an embodiment of
the present invention in which a stage of reaction of a compound B
is carried out in the first reactor 2a. The reactor 2b is in the
regeneration phase. A stage of reaction of a compound A is carried
out in the third reactor 3. Each of the reactors 2a, 2b and 3
respectively comprises a catalyst bed 21a, 21b or a preliminary
catalyst bed 21c. The first reactor 2a is fed with reaction
mixture, i.e. with compound B and with hydrofluoric acid, at the
bottom via the feeding device 16, the latter being fed by a device
for feeding with hydrofluoric acid 10 and by the second collecting
pipe 17 resulting from the separation unit 4. The valve 7 is
positioned so as to make it possible to convey the reaction mixture
to the first reactor 2a. The second reactor 2b is connected at the
bottom to a device for feeding with regeneration stream 11 via a
valve 8. The valves 7 and 8 connected to the first reactor 2a and
to the second reactor 2b make it possible to change the reactors
from a configuration in which a catalytic reaction is carried out
to a configuration in which a regeneration stage is carried out.
The stream of products resulting from the first reactor 2a is
conveyed to the intermediate collecting device 19 via a valve 5
configured for this purpose. The regeneration stream exits from the
second reactor 2b in order to be conveyed to the device for
collecting stream of gas resulting from the regeneration 12; this
being regulated via the valve 6. The valve 22 makes it possible to
regulate the streams entering the device for feeding the third
reader 20. Thus, said device for feeding the third reader 20 can be
fed with the streams originating from the intermediate collecting
device 19 and the device for feeding with preliminary reaction
mixture 13, or said device for feeding the third reader 20 can be
fed by a device for feeding with regeneration stream 14. The stream
entering the third reactor 3 is brought into contact with the
catalytic bed 21c. The stream of products resulting from the third
reactor 3 is subsequently conveyed to the separation unit 4 by the
device for collecting stream of products from the third reactor 18.
The valve 24 makes it possible to direct the stream of products to
the separation unit 4 or to a device for collecting stream of gas
resulting from the regeneration of the third reactor 12'. The
separation unit 4 comprises a first pipe 15 and a second pipe 17,
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 the compound B.
As represented in FIG. 1a, the regeneration stream in the second
reactor 2b and the stream of the reaction mixture in the first
reactor 2a are in the same direction.
[0200] FIG. 1b illustrates an embodiment identical to that
presented in FIG. 1a, with the exception of the direction of the
regeneration stream and of the reaction stream, i.e. of the
reaction mixture, in the first reactor 2a and the second reactor
2b. Thus, in FIG. 1b, the regeneration stream in the second reactor
2b and the reaction stream in the first reactor 2a are reversed. In
this case, the device for feeding with regeneration stream 11 feeds
the second reactor 2b by the top via the valve 6, whereas the
device for feeding with reaction mixture 16 still feeds the first
reactor by the bottom of the latter. The regeneration stream exits
from the second reactor 2b in order to be conveyed to the device
for collecting stream of gas resulting from the regeneration 12 via
the valve 8. The third reactor 3 is configured as described in FIG.
1a.
[0201] FIG. 1c illustrates an embodiment in which the first reactor
2a is in the regeneration phase, whereas the second reactor 2b is
in the reaction phase. The second reactor 2b is fed by the device
for feeding with reaction mixture 16 via the valve 8 configured for
this purpose. The stream of products resulting from the second
reactor 2b feeds the intermediate collecting device 19. Conversely,
the first reactor 2a is fed by the device for feeding with
regeneration stream 11 by the top of the reactor. The gases present
in the first reactor exit, in this case, at the bottom of the
reactor to the device for collecting stream of gas resulting from
the regeneration 12. The valves 5 and 7 are thus configured in
order to make it possible for the regeneration stream to pass
inside the first reactor 2a. The third reactor 3 is configured as
described in FIG. 1a.
[0202] FIGS. 2a, 2b, 2c, 2d and 2e illustrate embodiments in which
the third reactor 3 is in the regeneration phase. As explained
above, in this case, the first reactor 2a and the second reactor 2b
are not in the reaction phase. The first reactor 2a and the second
reactor 2b are, independently of one another, either in the
regeneration phase or in the waiting phase, during which no stream
circulates inside these. More particularly, FIG. 2a illustrates a
plant according to an embodiment in which a stage of regeneration
of the catalyst is carried out in the first reactor 2a and in the
second reactor 2b. A stage of regeneration of the preliminary
catalyst is carried out in the third reactor 3. Each of the
reactors 2a, 2b and 3 respectively comprises a catalyst bed 21a,
21b or a preliminary catalyst bed 21c. The first reactor 2a and the
second reactor 2b are fed at the top with a regeneration stream
dispensed by the device for feeding with regeneration stream 11.
The valves 5 and 6 are positioned so as to make it possible to
convey the regeneration stream to the first reactor 2a and the
second reactor 2b. The stream of gas resulting from the
regeneration in the first reactor 2a and the second reactor 2b are
discharged to the device for collecting stream of gas resulting
from the regeneration 12. The valves 7 and 8 are configured so as
to make it possible to convey the stream of gas resulting from the
regeneration of the reactors 2a and 2b to the device for collecting
stream of gas resulting from the regeneration 12. The third reactor
3 is fed at the bottom by a feeding device 20 comprising a
regeneration stream resulting from the device for feeding with
regeneration stream 14 via the valve 22 configured for this
purpose. The regeneration stream passes through the catalytic bed
21c of the third reactor 3. The stream of gas resulting from the
regeneration exits at the top of the third reactor 3 to the device
for collecting products resulting from the third reactor 18. This
regeneration gas stream is conveyed to the device for collecting
the streams of gas resulting from the regeneration 12'. The valve
24 is thus configured in order to connect the device for collecting
products resulting from the third reactor 18 to the device for
collecting the streams of gas resulting from the regeneration 12'.
The device for collecting the streams of gas resulting from the
regeneration 12' can be identical to the device for collecting the
streams of gas resulting from the regeneration 12. Alternatively,
it is possible to have a single device for collecting the streams
of gas resulting from the regeneration 12. In this case, the device
for collecting products resulting from the third reactor 18 is
connected to the device for collecting the streams of gas resulting
from the regeneration 12, this device also being fed by the streams
of gas resulting from the regeneration of the first reactor 2a and
of the second reactor 2b.
[0203] FIG. 2b illustrates an embodiment of the present invention
in which the second reactor 2b and the third reactor 3 are in the
regeneration phase, whereas the first reactor 2a is in the waiting
phase. Thus, the second reactor 2b is fed at the top by the device
for feeding with regeneration stream 11. The regeneration stream
passes through the catalytic bed 21b in order to exit at the bottom
of the second reactor 2b and to be conveyed to the device for
collecting the stream of gas resulting from the regeneration 12.
The third reactor 3 is fed at the bottom by a feeding device 20
comprising a regeneration stream resulting from the device for
feeding with regeneration stream 14 via the valve 22 configured for
this purpose. The regeneration stream passes through the catalytic
bed 21c of the third reactor 3. The stream of gas resulting from
the regeneration exits at the top of the third reactor 3 to the
device for collecting products resulting from the third reactor 18.
This regeneration gas stream is conveyed to the device for
collecting the streams of gas resulting from the regeneration 12'.
The valve 24 is thus configured in order to connect the device for
collecting products resulting from the third reactor 18 to the
device for collecting the streams of gas resulting from the
regeneration 12'. No stream circulates in the first reactor 2a. The
valves 5 and 7 are configured for this purpose.
[0204] FIG. 2c illustrates a specific embodiment of the present
invention in which the second reactor 2b and the third reactor 3
are in the regeneration phase, whereas the first reactor 2a is in
the waiting phase, the second reactor 2a and the third reactor 3
being fed with regeneration stream by the same device for feeding
with regeneration stream 11. The regeneration stream 11 is conveyed
to the third reactor 3 via the feeding device 20 and the valve 22
configured for this purpose.
[0205] FIG. 2d illustrates a specific embodiment of the present
invention in which the first reactor 2a, the second reactor 2b and
the third reactor 3 are in the regeneration phase. The first
reactor 2a and the second reactor 2b are regenerated in series.
Thus, the regeneration stream 11 feeds the second reactor 2b by the
top of the reactor via the valve 6. The regeneration stream is
discharged at the bottom of the reactor 2b in order to be conveyed
via the valve 8, the pipe 30 and the valve 5 to the top of the
first reactor 2a. The regeneration stream is injected into the
first reactor 2a in order to exit at the reactor bottom. The stream
of gas resulting from the regeneration is collected in the device
for collecting the streams of gas resulting from the regeneration
12.
[0206] FIG. 2e illustrates a specific embodiment of the present
invention in which the second reactor 2b and the third reactor 3
are in the regeneration phase, whereas the first reactor 2a is in
the waiting phase. The second reactor 2b and the third reactor 3
are regenerated in series by the same device for feeding with
regeneration stream 11. The regeneration stream 11 is conveyed to
the third reactor 3 via the feeding device 20 and the valves 6 and
22 configured for this purpose. The stream of gas resulting from
the regeneration exits at the top of the third reactor 3 to the
device for collecting products resulting from the third reactor 18.
This regeneration gas stream is conveyed to the device for
collecting the streams of gas resulting from the regeneration 12'.
The valve 24 is thus configured in order to connect the device for
collecting products resulting from the third reactor 18 to the
device for collecting the streams of gas resulting from the
regeneration 12'.
[0207] FIG. 3a illustrates a specific embodiment of the present
invention in which the second reactor 2b and the third reactor 3
are in the regeneration phase, the first reactor 2a being in the
waiting phase. In this embodiment, the reactors can be fed with
regeneration stream either at the top or at the bottom of the
reactor by a device configured in order to be connected both at the
top and at the bottom of the reactors. This makes it possible to
regenerate alternately by the bottom of the reactor and by the top
of the reactor. The second reactor 2b is fed at the top by the
device for feeding with regeneration stream 11 via valves 25 and 6
configured for this purpose. The regeneration stream passes through
the catalytic bed 21b in order to exit at the bottom of the second
reactor 2b and to be conveyed to the device for collecting the
stream of gas resulting from the regeneration 12 via the valves 8
and 25'. The third reactor 3 is fed at the top by a feeding device
20 comprising a regeneration stream resulting from the device for
feeding with regeneration stream 14 via the valve 24 configured for
this purpose. The regeneration stream passes through the catalytic
bed 21c of the third reactor 3. The stream of gas resulting from
the regeneration exits at the bottom of the third reactor 3 to the
device for collecting products resulting from the third reactor 18.
This regeneration gas stream is conveyed to the device for
collecting the streams of gas resulting from the regeneration 12'.
The valve 24' is thus configured in order to connect the device for
collecting products resulting from the third reactor 18 to the
device for collecting the streams of gas resulting from the
regeneration 12'. No stream circulates in the first reactor 2a.
[0208] By modifying the configuration of the valves 24 and 24', the
third reactor 3 can be regenerated by the bottom of the reactor.
This is illustrated in FIG. 3b. The first reactor 2a and the second
reactor 2b are configured in an identical way to that described in
detail in connection with FIG. 3a. For its part, the third reactor
3 is fed at the bottom by a feeding device 20 comprising a
regeneration stream resulting from the device for feeding with
regeneration stream 14 via the valves 22 and 24' configured for
this purpose. The stream of gas resulting from the regeneration is
conveyed to the device for collecting products 18 at the reactor
top. This regeneration gas stream is conveyed to the device for
collecting the streams of gas resulting from the regeneration 12'.
The valve 24 is thus configured in order to connect the device for
collecting products resulting from the third reactor 18 to the
device for collecting the streams of gas resulting from the
regeneration 12'.
[0209] FIG. 3c illustrates a specific embodiment of the present
invention in which the three reactors are in the regeneration
phase. The first reactor 2a and the second reactor 2b are fed with
regeneration stream by the device for feeding with regeneration
stream 11. The valves 5, 6 and 25 are configured in order to make
this conveyance possible. In this embodiment, the first reactor 2a
and the second reactor 2b are fed at the top with the regeneration
stream which respectively passes through the catalytic beds 21a and
21b. The stream of gas resulting from the regeneration is
discharged from the first reactor 2a and from the second reactor 2b
to the device for collecting the stream of gases resulting from the
regeneration 12. The valves 7, 8 and 25' are configured in order to
make this conveyance possible. The third reactor 3 is regenerated
by the bottom of the reactor. The third reactor 3 is thus fed at
the bottom by a feeding device 20 comprising a regeneration stream
resulting from the device for feeding with regeneration stream 14
via the valves 22 and 24' configured for this purpose. The stream
of gas resulting from the regeneration is conveyed to the device
for collecting products 18 at the reactor top. This regeneration
gas stream is conveyed to the device for collecting the streams of
gas resulting from the regeneration 12'. The valve 24 is thus
configured in order to connect the device for collecting products
resulting from the third reactor 18 to the device for collecting
the streams of gas resulting from the regeneration 12'. Of course,
it is possible to have just one device for collecting the streams
of gas resulting from the regeneration 12. In this case, the device
for collecting products resulting from the third reactor 18 is
connected to the device for collecting the streams of gas resulting
from the regeneration 12, this device also being fed by the streams
of gas resulting from the regeneration of the first reactor 2a and
of the second reactor 2b. Alternatively, the direction of the
regeneration stream can be modified in the first reactor 2a, the
second reactor 2b and/or the third reactor 3. The valves 5, 6, 7,
8, 22, 24, 24', 25 and 25' are then configured in order to make it
possible to convey the regeneration stream in the desired
direction. This can be determined as a function of the significant
or insignificant presence of coke in the reactor taken into
consideration and especially of the place where the coke is formed,
i.e. at the bottom or at the top of the reactor.
[0210] FIGS. 1a to 3c illustrate a plant in which the separation
unit is positioned at the outlet of the third reactor, so as to
treat the stream of products resulting from the latter. FIGS. 4a to
4c illustrate a plant in which the separation unit is positioned at
the outlet of the first reactor 2a and of the second reactor
2b.
[0211] In the embodiment illustrated in FIG. 4a, the first reactor
2a is in the reaction phase, that is to say that a stage of
catalytic reaction of the compound B in the presence of HF is
carried out in the this reactor. The third reactor 3 is in the
phase of manufacture of the compound B, i.e. reaction of the
compound A with HF. The second reactor 2b is in the regeneration
phase. The third reactor 3 is fed, by the device for feeding the
third reader 20, with a stream of reaction mixture originating from
the device for feeding with preliminary reaction mixture 13 and
from the second collecting pipe 17. The preliminary reaction
mixture comprises the compound A and hydrofluoric acid. The second
collecting pipe 17 can comprise hydrofluoric acid and
2-chloro-3,3,3-trifluoropropene. A valve 22 makes it possible to
regulate the streams resulting from the device for feeding with
preliminary reaction mixture 13 and from the second collecting pipe
17. A valve 26 and an intermediate pipe 27 can be positioned
between the second collecting pipe 17 and the valve 22. The valve
26 can make it possible to convey the products from the second
collecting pipe 17 to the first reactor 2a and the second reactor
2b via an intermediate pipe 28 and the feeding device 16 without
passing through the third reactor 3. The preliminary reaction
mixture resulting from the device for feeding the third reader 20
comes into contact with the preliminary catalyst present in the
catalytic bed 21c. The products of the reaction are conveyed, via
the device for collecting stream of products from the third reactor
18, to the device for feeding 16 the first reactor 2a or the second
reactor 2b. The device for collecting stream of products from the
third reactor 18 comprises in particular the compound B. The
products resulting from the third reactor can be mixed with
hydrofluoric acid resulting from the device for feeding with
hydrofluoric acid 10 and/or with the products conveyed by the
second collecting pipe 17 via the intermediate pipe 28, in order to
form the reaction mixture used in the reaction stage carried out in
the first reactor 2a. The reaction mixture is brought into contact,
in the first reactor 2a, with the catalyst present in the catalytic
bed 21a. The products resulting from this reaction stage in the
first reactor 2a are conveyed to the intermediate collecting device
19 and to the separation unit 4 described in connection with FIG.
1a. The second reactor 2b is in the regeneration phase. The
regeneration stream is conveyed, by the device for feeding with
regeneration stream 11, to the top of the second reactor 2b. The
stream of gas resulting from the regeneration of the catalyst
present in the catalytic bed 21b is conveyed to the device for
collecting the streams of gas resulting from the regeneration 12.
The direction of the reaction stream and of the regeneration stream
is reversed in this embodiment.
[0212] FIG. 4b illustrates an embodiment in which the first reactor
2a is in the regeneration phase and the second reactor 2b carries
out a stage of reaction of the compound B with HF. The third
reactor 3 carries out a stage of reaction of a compound A with HF,
as described in FIG. 4a. In this embodiment, the streams in the
first reactor 2a and the second reactor 2b are in the same
direction.
[0213] FIG. 4c illustrates an embodiment as described in connection
with FIG. 4a, except that the products from the second collecting
pipe 17 are conveyed to the first reactor 2a via an intermediate
pipe 28 and the feeding device 16 without passing through the third
reactor 3.
[0214] 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. 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.
* * * * *