METHOD AND INSTALLATION FOR SEPARING A MIXTURE COMPRISING AT LEAST ONE FLUORIDED FLUID AND ONE OR MORE CONTAMINANTS

Abstract

The invention relates to a method and installation for recycling a mixture comprising at least one fluorinated fluid, the mixture comprising one or more fluorinated chemical components and one or more contaminants selected from one or more hydrocarbons and / or one or more fluorinated contaminants, including a double membrane filtration step to reduce the contaminant content of the mixture. Figure for the abstract: Figure 1

Description

Title of the invention: METHOD AND INSTALLATION FOR SEPARING A MIXTURE COMPRISING AT LEAST ONE FLUORIDED FLUID AND ONE OR MORE CONTAMINANTS Technical field of the invention

[0001] The invention relates to the field of Hydrofluorocarbons (HFCs), Hydrofluoroolefins (HFOs), and / or Hydrochlorofluoroolefins (HCFOs) and relates to a process for recycling substances contained in mixtures comprising at least one fluorinated fluid and one or more contaminants. Technological background

[0002] Fluorinated chemical components usable as refrigerants, aerosol propellants, extinguishing agents or expanding agents are known under the designation of HydroFluoro-Carbide (HFC) molecules (composed of hydrogen, fluorine and carbon atoms), HydroFluoro-Olefins (HFO) and HydroChloroFluoro-Olefin (HCFO).

[0003] HFCs, HFOs, and HCFOs enable the implementation of a thermodynamic cycle in a cooling device (such as a cold room or a freezer, for example) or in a heating device (such as a heat pump, for example). They can also be used as aerosol propellants, extinguishing agents, or expanding agents.

[0004] A fluorinated fluid commonly comprises a pure chemical component, or pure molecule, or a mixture of chemical components. Among the HFC / HFO / HCFO components, the main ones known are R-1234yf / ze, R-134a, R-32, R-227ea, R-125, R-152a and R-143a used alone or in mixtures with other components.

[0005] Nowadays, HFCs have replaced both chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) as refrigerants, spray propellants, and insulating foams because they do not deplete the ozone layer and have a lower global warming potential (GWP) than the latter. Nevertheless, their contribution to global warming is significant because, even though their lifetime is relatively short, their GWP over one hundred years can be several thousand times greater than that of CO2.

[0006] Thus, the F-Gas legislation limits their use and encourages the recycling and reuse of these products. Reducing their consumption, or at least their release into the atmosphere, is one of the challenges for the coming years. Indeed, HFC emissions have been rising since the 1990s, while current regulations aim to reduce their use. Known alternatives to HFCs include For example, they use HFOs or hydrocarbons such as propane (R290), which have a much lower GWP. For example, the GWP of R32 is 675 and that of R125 is 3500, while that of R290 is 3, according to the IPCC's Fourth Assessment Report.

[0007] Unfortunately, replacing some of the fluorinated chemical components with hydrocarbons in refrigerants or refrigerant mixtures complicates the recycling process, particularly the possibilities of separating the different substances using conventional distillation methods. A solution therefore remains to be found to improve the recycling of mixed fluorinated fluid mixtures, insofar as they comprise either different types of fluorinated chemical components or both fluorinated chemical components and hydrocarbons.

[0008] The invention aims to provide a solution to one or more problems and drawbacks encountered in the prior art. In particular, the invention aims to provide a method for recycling a plurality of chemical components from a chemical mixture comprising at least one fluorinated chemical component and one or more contaminants selected from one or more hydrocarbons and / or one or more fluorinated contaminants. Presentation of the invention

[0009] To this end, according to a first aspect, the invention relates to a process for recycling a mixture comprising at least one fluorinated fluid, notable in that it comprises:

[0010] a) the supply, in the form of an initial flow, of a mixture comprising at least one fluorinated fluid; the mixture comprising one or more fluorinated chemical components and one or more contaminants selected from one or more hydrocarbons and / or one or more fluorinated contaminants;

[0011] b) membrane filtration of the initial stream so as to obtain a purified stream comprising a contaminant content lower than the contaminant content of the initial stream and a contaminant-enriched stream, said membrane filtration comprising at least two successive membrane filtration substeps; and

[0012] c) the recovery of the purified stream and / or the stream enriched in contaminants for reuse and / or recycling.

[0013] As will be understood from the definition just given, the invention proposes to perform a double membrane filtration of a mixture comprising at least one fluorinated fluid in order to obtain a purified stream depleted of contaminants and a stream enriched in contaminants. According to the invention, the purified stream is the permeate and the stream enriched in contaminants (for example, in hydrocarbons when present) is the retentate.

[0014] The invention finds a particular application in the decontamination of streams of mixtures of refrigerants containing hydrocarbon contaminants and in the separation of mixtures of fluorinated chemical compounds. The purified and / or enriched streams thus generated can be reused directly or directed to an additional recycling facility comprising one or more units for separating the fluorinated chemical components for recycling via conventional channels.

[0015] The invention is remarkable in that it allows, through this specific contaminant separation step, for the overall efficiency of a recycling process for a mixture containing at least one fluorinated fluid to be improved. Indeed, contamination of mixtures containing at least one fluorinated fluid by contaminants, such as hydrocarbons, could, when the hydrocarbon content was too high, affect the yield of distillation processes, or even make recycling certain mixtures impossible. It has been found that implementing a preliminary contaminant separation step improves distillation capacity and thus enhances the overall efficiency of the recycling process. In the case of fluorinated contaminants, the separation and purification of the fluorinated chemical components is improved.

[0016] According to one embodiment, the initial stream comprises one or more fluorinated contaminants and the, or at least one, fluorinated contaminant is 1,1,1,2,3,3,3-heptafluoropropane (R227ea) and / or the initial stream comprises one or more fluorinated contaminants and step c) comprises the recovery of the contaminant-enriched stream and its recycling.

[0017] According to one embodiment, the initial stream comprises one or more hydrocarbons selected from the group comprising propane and isobutane; and / or the initial stream comprises one or more hydrocarbons, and step c) comprises the recovery of the purified stream and its recycling.

[0018] Preferably, the initial stream comprises one or more fluorinated chemical components selected from hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFOs), and hydrochlorofluoroolefins (HCFOs); more preferably, the initial stream comprises one or more fluorinated chemical components selected from hydrofluorocarbons (HFCs) and / or hydrofluoroolefins (HFOs). According to the invention, step b) of membrane filtration comprises at least two successive membrane filtration substeps. Indeed, as shown in the examples, implementing two-stage filtration, i.e., in which at least two membrane filtration modules are arranged in series, significantly improves the separation of contaminants such as hydrocarbons.As will be understood, each sub-step of filtration generates a permeate and a retentate, the second sub-step of filtration is carried out on the permeate from the first sub-step of filtration.

[0019] Preferably, each membrane filtration substep generating a permeate and a retentate, the retentate from the second substage of membrane filtration is recycled so as to be mixed into the initial stream.

[0020] According to a preferred embodiment, step b) of membrane filtration includes at least one substep of filtration using a membrane comprising at least one layer of a material selected from polyethersulfone (PES), polysulfone (PSU), polyvinylidene fluoride (PVDF), polyether block copolymer and polyamide block copolymer (PEBA), polypropylene (PP), cellulose acetate (AC), polytetrafluoroethylene (PTFE), sulfonated polyphenylene sulfone (sPPSU), cellulose acetate butyrate (CAB), polyhedral oligomeric silsesquioxane (POSS), or polydimethylsiloxane (PDMS). Preferably step b) of membrane filtration includes at least one substep of filtration using a membrane comprising at least one layer of a material chosen to be a polyether block polyamide copolymer (PEBA) and / or a polyethersulfone (PES).

[0021] For example, step b) of membrane filtration includes at least one substep of filtration using a multilayer membrane comprising a layer of polyether block copolymer material and polyamide block copolymer (PEBA), and a layer of polyethersulfone (PES).

[0022] Preferably, the polyamide block comprises at least one polyamide selected from polyamide 6, polyamide 11 and polyamide 12; preferably, polyamide 6.

[0023] For example, the initial stream supplied in step a) comprises a hydrocarbon content greater than or equal to 0.5% by weight relative to the total weight of the initial stream; for example greater than or equal to 1.0%.

[0024] For example, the initial flow supplied in step a) includes a hydrocarbon content of 0.5% to 30% by weight relative to the total weight of the initial flow.

[0025] For example, step b) is conducted so as to obtain a hydrocarbon content of less than 5.0% by weight relative to the total weight of the purified stream; preferably, less than or equal to 4.0% by weight; preferably less than or equal to 3.0% by weight; preferably less than or equal to 2.5% by weight. Indeed, it has been found that a hydrocarbon content that is too high, such as a content exceeding 5.0% by weight, will degrade the distillation yield during the recycling of the purified mixture and / or the contaminant-enriched stream that can be carried out during step c).

[0026] For example, step b) is conducted so as to obtain a purified stream with a hydrocarbon content reduced by at least a factor of 4 compared to the hydrocarbon content of the initial stream, preferably by at least a factor of 5, more preferably by at least a factor of 6; more preferably by at least a factor of 8.

[0027] According to a preferred embodiment, the initial flow comprises at least two fluorinated chemical components and step c) of recycling includes the separation of said fluorinated chemical components by distillation.

[0028] In one embodiment, the purified stream includes a fluorinated component and step c) includes recycling said purified stream by at least one purification step or substep; preferably the purification step is carried out by simple distillation on at least one simple distillation column.

[0029] In one embodiment, the purified stream is an azeotropic mixture and step c) comprises recycling said purified stream including one or more distillation substeps selected from at least one sub-step of simple distillation on a simple distillation column; and / or at least one advanced distillation substep by pressure balance; and / or at least one advanced distillation substep of distillation by extraction.

[0030] Preferably, the purified stream is an azeotropic mixture and step c) comprises recycling said purified stream including one or more distillation substeps comprising at least one simple distillation substep on a simple distillation column followed by one or more advanced distillation substeps selected from at least one advanced distillation substep by pressure balance; and / or at least one advanced distillation substep of distillation by extraction.

[0031] According to a second aspect, the invention relates to an installation for implementing the process according to the first aspect, notable in that it comprises a membrane filtration unit comprising at least two membrane filtration modules arranged in series.

[0032] Preferably, the installation further comprises a distillation unit including: one or more simple distillation columns; and / or one or more columns configured to allow the implementation of advanced extraction distillation, and / or one or more columns configured to allow the implementation of advanced pressure balance distillation.

[0033] Preferably, the installation further comprises a distillation unit including: one or more simple distillation columns; and one or more columns configured to allow the implementation of a advanced distillation by extraction. Presentation of the figures

[0034] The invention will be well understood and other aspects and advantages will become clear upon reading the following description given with reference to the attached figures listed below.

[0035] [Fig.1] Fig.1 illustrates an example of the realization of an installation according to the invention.

[0036] [Fig.2] The [Fig.2] is the representation of a thin film composite membrane stage with a flow pattern in the feed and permeate streams.

[0037] [Fig. 3] Figure 3 is a graph illustrating the concentration of HFC+HFO in the permeate stream versus the recovery of HFC+HFO as a function of the feed pressure (1-8 bar) and the membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h₁. Membrane thickness = 2 µm. The feed composition is 90% by weight of HFC + HFO and 10% by weight of HC (R600a + R290).

[0038] [Fig. 4] Figure 4 is a graph representing the concentration of R32+R125 in the permeate stream versus the recovery of R32+R125 as a function of the feed pressure (1-8 bar) and the membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h₁. Membrane thickness = 2 µm. The feed composition is 40% by weight of R32, 40% by weight of R125, 10% by weight of R600a, and 10% by weight of R290.

[0039] [Fig. 5] Figure 5 allows for a comparison of one-stage and two-stage HFC+HFO purification: concentration of HFC+HFO in the permeate stream versus recovery of HFC+HFO as a function of feed pressure (1-8 bar) and membrane surface area. Each data point represents a combination of feed pressure and membrane surface area. Feed rate = 10 kg h₁. Membrane thickness = 2 µm. The feed composition is 90% by weight of HFC + HFO and 10% by weight of HC (R600a + R290).

[0040] [Fig. 6] Figure 6 allows for a comparison of the purification of R32+R125 with one and two steps: concentration of R32+R125 in the permeate stream versus recovery of R32+R125 as a function of feed pressure (1-8 bar) and membrane surface area. Each data point represents a combination of feed pressure and membrane surface area. Feed rate = 10 kg h⁻¹. Membrane thickness = 2 µm. The feed composition is 40% by weight of R32, 40% by weight of R125, 10% by weight of R600a, and 10% by weight of R290.

[0041] [Fig. 7] Figure 7 allows for a comparison of the purification of R227ea with one and two stages: concentration of R227ea in the retentate stream versus recovery of R227ea as a function of the feed pressure (1-4 bar) and the membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h⁻¹ 1. Membrane thickness = 2 µm. The composition of the feed is 70% by weight of R227ea, 20% by weight of R1234ze and 10% by weight of R134a. Detailed description

[0042] In the following description, the term "include" is synonymous with "include" and is not limiting in that it permits the presence of other elements in the described installation or other steps in the process to which it relates. It is understood that the term "include" includes the terms "consist of." Throughout the description, the various figures use the same reference numerals to designate identical or similar entities.

[0043] The invention relates to a process for recycling a mixture comprising at least one fluorinated fluid and an installation for carrying out such a process. The process and the installation will now be described jointly with reference to [Fig. 1].

[0044] According to the invention, the recycling process for a mixture 1 comprising at least one fluorinated fluid is remarkable in that it comprises:

[0045] a) the supply, in the form of an initial stream 3, of a mixture 1 comprising at least one fluorinated fluid; the mixture 1 comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more contaminants selected from one or more hydrocarbons and / or one or more fluorinated contaminants; and

[0046] b) membrane filtration of the initial stream 3 so as to obtain a purified stream 5 comprising a contaminant content lower than the contaminant content of the initial stream 3 and a contaminant-enriched stream 33, said membrane filtration comprising at least two successive membrane filtration substeps; and

[0047] c) the recovery of the purified stream 5 and / or the stream enriched in contaminants 33 for the purpose of their reuse and / or recycling.

[0048] In one embodiment, step c) includes recovering the purified stream 5 and / or the contaminant-enriched stream 33 for reuse. Indeed, depending on the composition of the initial mixture, the purified stream 5 and / or the contaminant-enriched stream 33 can be recovered and reused as is (without any further separation or purification steps).

[0049] In a preferred embodiment, step c) includes the recovery of the purified stream 5 for recycling. The recycling of the purified stream 5 is carried out by separation and / or purification of the fluorinated chemical components (41, 43, 49, 51, 55) contained in the purified stream 5 by distillation.

[0050] In a preferred embodiment, step c) includes the recovery of the contaminant-enriched stream 33 for recycling. The recycling of the contaminant-enriched stream 33 is carried out by separation and / or purification of the fluorinated contaminant(s). and / or hydrocarbon(s) contained in the stream enriched with contaminants by distillation.

[0051] According to one embodiment, the recycling process for a mixture 1 comprising at least one fluorinated fluid is notable in that it comprises:

[0052] a) the supply, in the form of an initial stream 3, of a mixture 1 comprising at least one fluorinated fluid; the mixture 1 comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more hydrocarbons; and

[0053] b) membrane filtration of the initial stream 3 so as to obtain a purified stream 5 comprising a hydrocarbon content lower than the hydrocarbon content of the initial stream 3, said membrane filtration comprising at least two successive membrane filtration sub-steps; and

[0054] c) the recovery of the purified stream and its recycling

[0055] According to one embodiment, the recycling process for a mixture 1 comprising at least one fluorinated fluid is notable in that it comprises:

[0056] a) the supply, in the form of an initial stream 3, of a mixture 1 comprising at least one fluorinated fluid; the mixture comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more fluorinated contaminants; and

[0057] b) membrane filtration of the initial stream 3 so as to obtain a purified stream 5 comprising a contaminant content lower than the contaminant content of the initial stream 3 and a contaminant-enriched stream 33, said membrane filtration comprising at least two successive membrane filtration substeps; and

[0058] c) the recovery of the stream enriched with contaminant 33 and its recycling.

[0059] The invention also relates to an installation for implementing the process, the installation comprising a membrane filtration unit 7 comprising at least two filtration modules (9, 11).

[0060] Preferably, the installation further comprises a distillation unit 13 comprising - one or more simple distillation columns 15; and / or - one or more columns (21, 23) configured to allow the setting of work of an advanced distillation by extraction, and / or - one or more columns (17, 19) configured to allow the implementation of advanced pressure balance distillation.

[0061] More preferably, the installation further comprises a distillation unit 13 comprising - one or more simple distillation columns 15; and / or - one or more columns (21, 23) configured to allow the setting of work of an advanced distillation by extraction.

[0062] Step a) of supplying a mixture comprising at least one fluorinated fluid.

[0063] According to the invention, the initial stream 3 is a mixture 1 comprising at least one fluorinated fluid; the mixture comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more contaminants selected from one or more hydrocarbons and / or one or more fluorinated contaminants. Preferably, the initial stream 3 is a mixture 1 comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more hydrocarbons. Preferably, the initial stream 3 is a mixture 1 comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more fluorinated contaminants.

[0064] According to the invention, a fluorinated contaminant is a fluorinated fluid that can be separated from the mixture in that it is present predominantly in the membrane filtration retentate.

[0065] According to the invention, a fluorinated chemical component is a fluorinated fluid that can be separated from the mixture in that it is present predominantly in the membrane filtration permeate.

[0066] The components of the mixture have been previously used to enable the implementation of a thermodynamic cycle in a plurality of independent thermodynamic devices. A thermodynamic device is understood to mean a cold-producing device (such as a cold room, a freezer, or a refrigerator), a heat-producing device (such as a heat pump), or even an aerosol propellant, for example. The fluorinated fluids have been used pure or in mixtures, and then collected in separate collection tanks during a collective or selective recovery operation.

[0067] According to a preferred embodiment of the invention, the process further comprises a step of identifying one or more fluorinated fluids in the initial stream, this step being carried out before step b) of membrane filtration. In particular, the process comprises a step of identifying one or more contaminants selected from among one or more hydrocarbons and / or one or more fluorinated contaminants in the initial stream.

[0068] For example, the identification step is a qualitative and quantitative analysis step preferably carried out by chromatographic analysis and the installation further includes an identification device, preferably a chromatographic analysis system.

[0069] For example, the initial stream 3 comprises one or more hydrocarbons selected from the group including methane (R50), ethane (R170), propane (R290), butane (R600), isobutane (R600a), pentane (R601), isopentane (R601a), and propene (R1270). Preferably, the initial stream 3 comprises propane (R290) and / or isobutane (R600a). In the context of the invention, the hydrocarbon(s) are contaminants in that they are present predominantly in the retentate.

[0070] For example, the initial stream 3 comprises at least one fluorinated contaminant being 1,1,1,2,3,3,3-heptafluoropropane (R227ea).

[0071] The hydrocarbon content of the initial stream 3 is for example at least 0.3% by weight based on the total weight of the initial stream; preferably at least 0.5% by weight; more preferably at least 0.8% by weight; more preferably at least 1.0% by weight; more preferably at least 5.0% by weight and even more preferably at least 10.0% by weight.

[0072] For example, the hydrocarbon content of the initial stream 3 is at most 70% by weight based on the total weight of the initial stream; preferably, at most 60% by weight; more preferably at most 50% by weight; more preferably at most 40% by weight; more preferably at most 30% by weight; and even more preferably at most 25% by weight. When the hydrocarbon content is too high, for example, when it exceeds 40% by weight based on the total weight of the initial stream, it is possible to perform a dilution step of the initial stream with another hydrocarbon-free stream in order to adjust the hydrocarbon content to be below 40%. Such a dilution step increases the overall efficiency of the process. Thus, step a) may include a substep for adjusting the hydrocarbon content.

[0073] For example, the hydrocarbon content of the initial stream 3 is between 0.3 and 70% by weight based on the total weight of the initial stream; preferably between 0.5 and 60% by weight; more preferably between 1.0 and 50% by weight and more preferably between 5.0 and 40% by weight.

[0074] For example, the initial stream 3 comprises one or more fluorinated fluids selected from hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFOs), and hydrochlorofluoroolefins (HCFOs); more preferably, the initial stream 3 comprises one or more hydrofluorocarbons (HFCs) and / or one or more hydrofluoroolefins (HFOs).

[0075] According to one embodiment of the invention, the initial flow 3 comprises at least one fluorinated chemical component (41, 43, 49, 51, 55) and preferably at least two distinct fluorinated chemical components (41, 43, 49, 51, 55).

[0076] In one embodiment, the initial flow 3 comprises one or more hydrofluorocarbon (HFC) fluorinated fluids selected from trifluoromethane (R23), difluoromethane (R32), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), 1,1-difluoroethane (R152a), 1,1,1,2,3,3,3-heptafluoropropane (R227ea), 1,1,1,2,3,3-hexafluoropropane (R236ea), 1,1,1,3,3,3-hexafluoropropane (R236fa), trifluoropropane (R263), difluoropropane (R272), the fluoropropane (R281), and the 1,1,1,3,3-pentafluorobutane (R365mfc).

[0077] Preferably, the initial stream 3 comprises one or more hydrofluorocarbon (HFC) fluorinated fluids selected from difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), and 1,1,1-trifluoroethane (R143a). Preferably, the initial stream 3 comprises one or more hydrofluorocarbon (HFC) fluorinated fluids selected from difluoromethane (R32), pentafluoroethane (R125), and 1,1,1,2-tetrafluoroethane (R134a). Preferably, the initial stream 3 comprises at least one HFC being difluoromethane (R32) and / or pentafluoroethane (R125).

[0078] In one embodiment, the initial stream 3 comprises one or more hydrofluoroolefin (HFO) fluorinated fluids selected from cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z), trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E), 2,3,3,3-tetrafluoropropene (R1234yf), and trans-1,3,3,3-tetrafluoropropene (R1234ze). Preferably, the initial stream 3 comprises at least one HFO being 2,3,3,3-tetrafluoropropene (R1234yf) and / or trans-1,3,3,3-tetrafluoropropene (R1234ze).

[0079] In one embodiment, the initial flow 3 comprises one or more fluorinated fluids of the hydrochlorofluorocarbon (HCFC) type selected from chlorodifluoromethane (R22), chlorofluoromethane (R31), 2,2-dichloro-1,1,1-trifluoroethane (R123), l-chloro-l,2,2,2-tetrafluoroethane (R124), l-chloro-l,l,2,2-tetrafluoroethane (R124a), 1,1-dichloro-l-fluoroethane (R141b), l-chloro-l,l-difluoroethane (R142b), and l,3-dichloro-l,l,2,2,3-pentafluoropropane (R225cb).

[0080] In one embodiment, the initial flow 3 comprises one or more fluorinated hydrochlorofluoroolefin (HCFO) type fluids selected from trans-l-chloro-3,3,3-trifluoropropene (R-1233zd(E)), cis-l-chloro-3,3,3-trifluoropropene (R-1233zd(Z)), and (Z)-1-Chloro2,3,3,3,-Tetrafluoropropene (R-1224yd(Z)).

[0081] The content of fluorinated chemical components (41, 43, 49, 51, 55) of the initial stream 3 is for example at least 20% by weight based on the total weight of the initial stream 3; preferably at least 30% or at least 40% by weight; more preferably at least 50% by weight and more preferably at least 60% by weight.

[0082] For example, the content of fluorinated chemical components (41, 43, 49, 51, 55) of the initial stream 3 is at most 97% by weight based on the total weight of the initial stream; preferably, at most 95% by weight; more preferably at most 92% by weight and more preferably at most 90% by weight.

[0083] For example, the content of fluorinated chemical components (41, 43, 49, 51, 55) of the initial stream 3 is between 30 and 97% by weight based on the total weight of the initial stream; preferably, between 40 and 95% by weight; more preferably, between 50 and 92% by weight. weight and more preferably between 60 and 90% by weight.

[0084] According to embodiments of the invention, step a) includes at least one sub-step of pretreatment of the refrigerant mixture 1 to obtain the initial flow 3. It is understood that the pretreatment sub-step(s) are carried out before step b) of membrane filtration by means of a pretreatment unit 25.

[0085] For example, the fluorinated fluid mixture 1 may or may not be compressed for storage purposes. When the fluorinated fluid mixture 1 is not compressed, step a) includes a compression substep in a compression unit 27. In one embodiment of the invention, the initial flow 3 is compressed to exhibit a pressure between 1 and 10 bar.

[0086] Preferably, before entering the membrane filtration unit 7, the initial stream 3 undergoes one or more pretreatment sub-steps to remove any traces of water, oil, and particles that could damage the membrane surface. This task can be performed by one or more coalescing filters (29, 31) placed in series, for example, two coalescing filters (29, 31) with cartridges of 0.1 µm² and 0.01 µm², respectively.

[0087] Alternatively, and according to an embodiment not shown, step a) includes a substep of drying the refrigerant mixture in a dehydration unit. Advantageously, the dehydration substep is carried out using a molecular sieve. For example, the refrigerant mixture, or a portion thereof, is compressed to cause the condensation of at least some of its water content to produce a two-phase stream having liquid and gaseous phases. The gaseous phase is introduced into the dehydration unit to remove at least some of its water content and produce a dried gaseous phase.

[0088] Regardless of the pretreatment chosen, a person skilled in the art will benefit from the initial stream 3 entering the membrane filtration unit 7 having a water content of no more than 10 ppm by weight relative to the total weight of the initial stream.

[0089] For example, step a) includes a substep for adjusting the hydrocarbon content of the refrigerant mixture 1 by mixing different collected refrigerant streams. Indeed, when the contaminant content, for example hydrocarbons, is greater than 40% by weight relative to the total weight of the initial stream, a person skilled in the art would benefit from diluting the initial stream with another stream free of hydrocarbons.

[0090] Step b) of membrane filtration and the membrane filtration unit

[0091] It will be understood that step b) of membrane filtration of the initial stream 3 in order to obtain a purified stream 5 comprising a hydrocarbon content lower than the hydrocarbon content of the initial stream 3, also makes it possible to obtain an enriched stream contaminants 33.

[0092] Membrane separation takes place in a membrane filtration unit 7 comprising at least one filtration module 9, and preferably at least two filtration modules (9, 11) arranged in series. When the membrane filtration unit 7 comprises a single filtration module 9, the filtration is said to be single-stage. When the membrane filtration unit 7 comprises several filtration modules (9, 11) arranged in series, the filtration is said to be multi-stage. Figure 1 illustrates the embodiment in which the membrane filtration unit 7 comprises two filtration modules (9, 11) arranged in series.

[0093] Each filtration module (9, 11) comprises one or more membranes arranged in parallel. The membrane(s) may be single-layer or multi-layer, preferably with at least one selective layer allowing the separation of hydrocarbons. Two product streams exit a filtration module (9, 11): a permeate stream (5, 35) (or permeate) containing the portion of the feed stream that passes through the membrane, and a retentate stream (33, 37) (or retentate) containing the portion of the feed stream that does not pass through the membrane. According to the invention, the purified stream is the permeate and the stream enriched with contaminants (for example, hydrocarbons) is the retentate. The retentate can then be treated as waste (for example in the case of a hydrocarbon-type contaminant) or purified by recycling for reuse (for example in the case of a fluorinated contaminant is 1,1,1,2,3,3,3-heptafluoropropane (R227ea)).Thus, according to the invention, the process may further include the recovery of the filtration retentate obtained in step b) and the recycling of said retentate. Preferably, the recycling of the retentate can be carried out by distillation.

[0094] The filtration step b) can be a single-stage filtration comprising a simple membrane filtration step or a multi-stage filtration in which a plurality of membrane filtration sub-steps are carried out successively.

[0095] According to the invention, step b) of membrane filtration comprises at least two successive membrane filtration substeps. Indeed, as shown in the examples, the implementation of multi-stage filtration, that is to say, in which several filtration modules (9, 11) are arranged in series, makes it possible to improve the hydrocarbon separation performance.

[0096] According to the invention, membrane filtration is carried out such that the contaminant(s) are predominantly in the filtration retentate (33, 37). Since each filtration substage generates a permeate and a retentate, subsequent filtration substages are performed on the permeate of the preceding filtration substage. In the case of two-stage filtration, the second filtration substage is performed on the permeate 35 of the first filtration substage.

[0097] Preferably, the retentate from the additional filtration substages is recycled so as to be mixed in the initial stream 3. In the case of two-stage filtration, the retentate 37 from the second filtration substage is recycled so as to be mixed in the initial stream 3.

[0098] Preferably, the retentate 33 from the first filtration substep is discharged for further processing.

[0099] Preferably, the membrane(s) of the filtration module(s) (9, 11) comprise at least one layer of a material selected to be a polyethersulfone (PES), a polysulfone (PSU), a polyvinylidene fluoride (PVDF), a polyether-block polyamide copolymer (PEBA), a polypropylene (PP), a cellulose acetate (AC), a polytetrafluoroethylene (PTFE), a sulfonated polyphenylene sulfone (sPPSU), cellulose acetate butyrate (CAB), polyhedral oligomer silsesquioxane (POSS), or a polydimethylsiloxane (PDMS). More preferably, the membrane(s) of the filtration module(s) (9, 11) comprise at least one layer of a polymer or copolymer comprising repeating units of a tetramethylene oxide, propylene oxide, or ethylene oxide monomer. For example, the polymer or copolymer comprises repeating motifs according to formula (1):

[0100] [Math.l] OO HO—|—C---PA----C---PE (1)

[0101] wherein PA is a polyamide selected from polyamide 6, polyamide 11 and polyamide 12, and PE is poly(ethylene oxide) or poly(tetramethylene oxide); preferably, PA is polyamide 6.

[0102] According to a preferred embodiment of the invention, the material of the or at least one layer of the filtration membrane is chosen to be a polyether block-polyamide block copolymer (PEBA). Preferably, the polyamide block comprises at least one polyamide selected from polyamide 6, polyamide 11, and polyamide 12; preferably, polyamide 6.

[0103] As is known, polyamide (PA) and polyether (PE) block copolymers result from the copolycondensation of reactive-end polyamide blocks with reactive-end polyether blocks. For example, the following can be reacted: - polyetherdiol and a dicarboxylic acid polyamide, - polyetherdiamine and a dicarboxylic acid polyamide, - polyetherdiol and a diamine polyamide.

[0104] French patent document FR 2 273 021 describes such copolymers formed from polyamide blocks and polyether blocks, the polyamide and polyether blocks being linked by an ester function. These products are sold under the trade name PEBAX® by ARKEMA. Examples of PEBAs usable within the scope of the invention are PEBAX® 1074, PEBAX® 2533, and PEBAX® 1657, commercially available from ARKEMA.

[0105] Thus, according to a preferred embodiment, step b) of membrane filtration includes at least one substep of filtration using a membrane comprising at least one layer of a material selected from polyethersulfone (PES), polysulfone (PSU), polyvinylidene fluoride (PVDF), polyether block copolymer and polyamide block copolymer (PEBA), polypropylene (PP), cellulose acetate (AC), polytetrafluoroethylene (PTFE), sulfonated polyphenylene sulfone (sPPSU), cellulose acetate butyrate (CAB), polyhedral oligomeric silsesquioxane (POSS), or polydimethylsiloxane (PDMS). Preferably step b) of membrane filtration includes at least one substep of filtration using a membrane comprising at least one layer of a material chosen to be a polyether block polyamide copolymer (PEBA) and / or a polyethersulfone (PES).

[0106] For example, step b) of membrane filtration includes at least one substep of filtration using a multilayer membrane comprising a layer of polyether block copolymer material and polyamide block copolymer (PEBA), and a layer of polyethersulfone (PES).

[0107] Preferably, step b) is conducted so as to obtain a hydrocarbon content of less than 5.0% by weight relative to the total weight of the purified stream 5; preferably less than or equal to 4.0% by weight, more preferably less than or equal to 3.0% by weight; and even more preferably less than or equal to 2.5% by weight.

[0108] For example, the purified stream comprises a hydrocarbon content of between 0.01% and less than 5.0% by weight relative to the total weight of the purified stream 5; preferably between 0.01% and 4.0% by weight, more preferably between 0.01% and 3.0% by weight; more preferably between 0.01% and 2.5% by weight. Step c) of recycling

[0109] The recycling step c) is carried out on the purified stream 5 and / or the contaminant-enriched stream 33. Preferably, when the initial stream 3 contains one or more fluorinated contaminants, a recycling step is carried out on the contaminant-enriched stream 33. Preferably, when the initial stream 3 contains one or more hydrocarbons, a recycling step is carried out on the purified stream 5.

[0110] According to a preferred embodiment, the initial flow 3 comprises a single component fluorinated chemical (41, 43, 49, 51, 55) and one or more hydrocarbons, and step c) of recycling is carried out on the purified stream and is a purification step of said fluorinated chemical component (41, 43, 49, 51, 55). This purification can be carried out by any means, preferably by distillation.

[0111] According to a preferred embodiment, the initial stream 3 comprises at least two fluorinated chemical components (41, 43, 49, 51, 55) and one or more hydrocarbons, and the recycling step c) is at least carried out on the purified stream and comprises at least one step for separating the fluorinated chemical components (41, 43, 49, 51, 55). This separation can be carried out by any means, preferably by distillation. Preferably, each separation step allowing the isolation of a fluorinated chemical component, or at least one of these separation steps, is followed by a purification step of the fluorinated chemical component that has been isolated.

[0112] According to a preferred embodiment, the initial stream 3 comprises at least one fluorinated chemical component (41, 43, 49, 51, 55) and one or more fluorinated contaminants, and step c) comprises recycling the purified stream 5 and / or the contaminant-enriched stream 33. The recycling of each stream may be a step of purification or separation of the fluorinated contaminant(s) and the fluorinated chemical component(s).

[0113] According to the invention, a fluorinated contaminant is a fluorinated refrigerant that can be separated from the refrigerant mixture in that it is predominantly present in the membrane filtration retentate.

[0114] According to the invention, a fluorinated chemical component is a fluorinated refrigerant that can be separated from the refrigerant mixture in that it is predominantly present in the membrane filtration permeate.

[0115] The processes for separating fluorinated refrigerants by distillation are known to those skilled in the art. In the case of zeotropic mixtures, it is possible to separate the different components by a simple distillation process using simple distillation columns.

[0116] In the case of azeotropic or pseudo-azeotropic mixtures, two advanced distillation processes are known: by pressure swing (known as "pressure swing" in English), and by extraction using a carrying agent, called solvent 45.

[0117] According to one embodiment of the invention, the purified stream 5 is an azeotropic mixture and step c) is a separation step of a mixture of fluorinated chemical components (41, 43, 49, 51, 55) and / or fluorinated contaminants comprising one or more distillation substeps selected from: - a simple distillation substage on a simple distillation column 15, - a pressure balance distillation substage using columns auxiliary distillations (17, 19), and - a sub-step of distillation by extraction using auxiliary distillation columns (21, 23).

[0118] Preferably, the purified stream 5 is an azeotropic mixture and step c) is a separation step of a mixture of fluorinated chemical components (41, 43, 49, 51, 55) and / or fluorinated contaminants comprising at least one simple distillation substep and one or more advanced distillation substeps selected from: - a pressure balance distillation substep, and - an extraction distillation substep.

[0119] Pressure balance distillation methods are known to those skilled in the art and employ two distillation columns (17, 19) operating under different pressures.

[0120] More specifically, a complex submixture 39 evolves successively, in a continuous circuit, in two columns (17, 19) set at different pressures. Each column (17, 19) has the role of separating one of the components (41, 43) of the complex submixture 39 according to the pressure to which it is set.

[0121] In the first distillation column 17, which is mainly used at a low pressure (P1), one of the two components 41 can be removed from the bottom of the column 17, while the azeotrope is removed from the top of the column and introduced into the second column 19, which operates at a higher pressure (P2), thus removing the azeotropic mixture. In the second column 19, the second compound 43 can be removed from the bottom, while an azeotropic mixture 57 is formed at the top. This latter mixture again has a significantly different composition from that of the submixture 39. This azeotropic mixture 57 is reintroduced into the first column 17.

[0122] Extractive distillation uses a solvent 45, called the entraining agent, which increases the volatility of one of the components or strongly modifies the activity coefficients of the substances to be separated in different directions, and thus the separation factor becomes significantly different from 1 (1 = azeotrope). Two columns (21, 23) are used. Typically, the solvent 45 is fed near the top of the first column 21 (called the extraction column), and the complex submixture 47 to be separated is introduced into a lower section of this column 21 to obtain the best possible mixing. The solvent 45 can be withdrawn from the bottom of this same column 21 along with one 51 of the substances to be separated. The second column 23 (called the regeneration column) is used to separate (regenerate) the solvent 45 and isolate the fluorinated chemical compound 51 to be extracted.

[0123] Such a process for separating a complex mixture of fluorinated chemical components (41, 43, 49, 51, 55) is known to those skilled in the art and is described, for example, in document FR3115036. Thus, preferably step c) of separation by dis- tillation includes the implementation of said process.

[0124] Preferably, the purified stream 5 is a complex mixture of fluorinated chemical components (41, 43, 49, 51, 55), and step c) comprises: - a substep of identifying in the purified stream 5 at least two submixtures (39, 47, 53), each submixture being a simple submixture 53 comprising a single fluorinated chemical component 55 or a complex submixture (39, 47) comprising a combination of fluorinated chemical components (41, 43, 48, 51), each complex submixture (39, 47) being associated either with a first secondary distillation group by a pressure balance distillation method, or with a second secondary distillation group by an extraction distillation method, - a primary distillation step, using a simple distillation column 15, so as to separate each identified submixture (39, 47, 53), and - a secondary distillation step, using at least two auxiliary extraction columns, of each complex submixture (39, 47) of the first group and the second group, wherein the complex submixtures 39 of the first group are separated by the pressure balance distillation method and the complex submixtures 47 of the second group are separated, using a solvent 45, by the extraction distillation method.

[0125] According to one embodiment of the invention, the same auxiliary columns can successively perform pressure-balancing distillation and extraction distillation. Such a configuration is advantageous in that it reduces the number of columns in the installation and therefore the associated costs.

[0126] Preferably, solvent 45 is selected from the following solvents: n-pentane, dichloromethane, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), heptanone, pentanone, cyclohexanone, and dimethyl ether. Preferably, the compound used is methyl isobutyl ketone (MIBK). Such a solvent advantageously provides a high separation factor and high extraction capacity for advanced distillation and recovery of the chemical component.

[0127] Preferably, several secondary distillation steps are carried out successively for each complex submixture (39, 47) of the first group and the second group.

[0128] Optionally, the separation of a fluorinated chemical component 55 from a simple submixture 53 includes a purification step carried out on said simple submixture 53.

[0129] When step c) includes both primary distillation substeps and Secondarily, the installation for implementing the process according to the invention comprises a distillation unit 13 comprising one or more simple distillation columns 15; preferably, the distillation unit 13 further comprises at least two auxiliary columns (17, 19, 21, 23) configured to allow the implementation of advanced distillation by extraction, and / or advanced distillation by pressure balance.

[0130] A procedure similar to that carried out on the purified stream can be carried out on the enriched stream when it includes one or more fluorinated contaminants.

[0131] Preferably, the installation includes: - a simple distillation column 15 configured to receive the purified stream 5 and carry out a primary distillation, so as to separate the purified stream 5 into at least two submixtures, - an electronic computer configured for: • identify in the chemical mixture the different submixtures (39, 47, 53), each submixture being a simple submixture 53 comprising a single chemical component 55 or a complex submixture (39, 47) comprising a combination of chemical components (41, 43, 49, 51), • associate each complex submixture (39, 47) either to a first secondary distillation group by a pressure balance method, or to a second secondary distillation group by an extraction distillation method, - at least two auxiliary columns (17, 19, 21, 23), configured to carry out secondary distillation and to allow extraction distillation by means of an entrainer, and / or pressure balance distillation, so as to separate all the chemical components (41, 43, 49, 51) of each submixture (39, 47).

[0132] Preferably, two auxiliary columns are configured to carry out secondary distillation and to allow successive distillation by extraction using an entrainer, then by pressure balance, so as to separate all the chemical components of each submixture. Examples

[0133] Example 1: Selection of the membrane and refrigerant mixtures

[0134] The results presented in the examples below were obtained using simulation software based on ideal (non-competitive) experimental permeability and selectivity data obtained at laboratory scale.

[0135] The membrane material used in this project is a block copolymer of polyethers and block polyamides, namely a thermoplastic elastomer composed of units The membrane consists of flexible poly(ethylene oxide) (PEO, 60% by weight) and rigid glassy segments of polyamide 6 (PA6, 40% by weight). The polyamide segments provide mechanical strength to the polymer and prevent PEO crystallization, resulting in a polymer material with good film-forming properties and high gas permeability. The membrane thickness is 2 µm.

[0136] The analysis of the experimental results concerning the pure permeation properties of 7 HFCs and HFOs and 2 hydrocarbons through the polymer membrane led to the definition of two refrigerant mixtures M1 and M2 whose composition is given in Table 1. A mixture of fluorinated refrigerants is also indicated in M3.

[0137] Table 1: Composition of the different refrigerant mixtures as mass percentages relative to the total weight of the mixture

[0138] [Tables 1] Refrigerant (% weight) Ml M2 M3 R32 16 40 - R125 26 40 - R134a 21 - 10 R1234yf 20 - - R1234ze 7 - 20 R227ea - - 70 R600a 5 10 - R290 5 10 -

[0139] The Ml mixture contains HFCs, HFOs and hydrocarbons. It is a mixture of type R448A in which 10% by weight of R32 has been replaced by hydrocarbons.

[0140] The M2 mixture contains HFCs and hydrocarbons. It is a mixture of type R410A in which 20% by weight of the HFCs has been replaced by hydrocarbons.

[0141] The M3 mixture contains a fluorinated contaminant of the HFC type 1,1,1,2,3,3,3-heptafluoropropane (R227ea). HFCs

[0142] - R32: difluoromethane - R125: pentafluoroethane - R 134a: 1,1,1,2-tetrafluoroethane - R227ea 1,1,1,2,3,3,3-heptafluoropropane HFOs

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151] - R1234yf: 2,3,3,3-Tetrafluoropropene - R1234ze: trans-l,3,3,3-Tetrafluoroprop-l-ene Hydrocarbons - R600a: isobutane - R290: propane Example 2: Process using a single-stage membrane separation unit and hydrocarbons The membrane separation step is conducted at a temperature of 25°C and under a maximum pressure of 8.0 bars. The mathematical model for a membrane separation unit was constructed taking into account the following assumptions: - The permeability to gases through the dense membrane layer is described by the solution-diffusion mechanism, which means that the permeability coefficient (P) is defined as the product of the sorption coefficient (S) and the diffusion coefficient (29). [Math.l] FF * 5 Where 5 is an equilibrium term related to the concentration of a component in the polymer phase, and 29 is a kinetic term related to the molecular movement of the permeable component across the membrane. - The transport of gas across a dense selective barrier is governed by the following expression. [Math.2] P • / X .A "" « kPpJ FpU■) where Ji is the molar flux of component i, Pi is the gas permeability coefficient, ô is the membrane thickness and Prj and Pp.i are the partial pressure of the component on either side of the membrane. - Gas permeability is independent of the feed composition (ideal gas permeability), i.e. that the simulation results do not take into account plausible competing effects resulting from feeding the membrane with gas mixtures. - Gas permeability depends on pressure. The permeability data for each HFC, HFO and HC have been described as a function of the pressure gradient applied across the membrane ( / Ipp following an exponential function).

[0152] [Math.3] p j :™- £ A çy -- -,-

[0153] where P(i) is a pre-exponential factor and m is a constant that provides information on the influence of pressure on gas permeability. A summary of the values ​​of the adjusted parameters for each gas is provided in Table 2. - The piston flow concentration model is developed in both the feed gas and the permeation gas flowing through the channels on both sides of the membrane. - Negligible pressure losses of the gaseous phase along the feed side. - Isothermal operation.

[0154] Table 2: Exponential fitting parameters to Eq. (3) of HFC, HFO and HC.

[0155] [Tables2] Parameters R32 R134a R125 R143a R227ea R1234yf R1234ze Pai (cross out) 110.78 58.02 15.10 8.22 4.54 8.25 26.24 m (bar-1) 0.1375 0.2366 0.1686 0.0766 0.484 0.1254 0.2676 Parameters R290 R600a Po,i (bar) 7.02 3.95 m (bar-1) 0.066 0.193

[0156] The schematic diagram of the gas separation process through a flat thin-film composite membrane is shown in [Fig.2].

[0157] The differential mass balances around each component in a slice of length dz are derived as follows,

[0158] [Math.4] (z - J, t71 <f È “L 72

[0159] [Math.5] jj?*

[0160] where F is the molar flow rate of component i, A is the membrane area, and z is the axial position along the module length. Furthermore, the transmembrane flux of each component (J) has been defined in Eq. 2. The proposed mathematical model is therefore formed by the system of equations (2), (3), (4) and (5). Performance of the separation process

[0161] The performance of the separation process is evaluated in terms of product purity and product recovery in the stream of interest (either the retentate or the permeate, depending on the case study). In each case study, product recovery is defined by Eq. (6) and purity is given by the mass concentration of the target component(s) in the product stream.

[0162] [Math.6] „ , Fhw rate of cwpsMt / in stream Prodoct recwerv ™.....—.......—.......-...............—.........-..................-................... * KwU ot campement / Filtration of the mixture (ml)

[0163] Figure 3 shows the concentration of HFC+HFO in the permeate stream versus the recovery of HFC+HFO as a function of the feed pressure (1-8 bar) and membrane area for mixture 1. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg / h*. Membrane thickness = 2 µm. The feed composition is 90% by weight of HFC + HFO and 10% by weight of HC (R600a + R290).

[0164] Table 3 illustrates an example of the membrane separation performance for the Ml mixture

[0165] Table 3

[0166] [Tables3] Retentate permeate (ml) Flow rate (kg / h) 10 4.2 5.8 Pressure (bar) 3.7 3.7 1.01 Refrigerant (% by weight) R32 16 7.05 22.5 R125 26 29.86 23.2 R134a 21 11.16 28.2 R1234yf 20 30.98 12.0 R1234ze 7 5.97 7.8 R290 5 8.38 2.5 R600a 5 6.60 3.8

[0167] As can be seen, the recovery and purity of HFC+HFO are 60.4% by weight (in the retentate) and 93.7% by weight (in the permeate), respectively. These product specifications are obtained with a feed pressure of 3.7 bar and a membrane modulus of 17 m² of permeation surface area. Filtration of mixture M2

[0168] Figure 4 represents the concentration of R32+R125 in the permeate stream by Report on the recovery of R32+R125 as a function of feed pressure (1-8 bar) and membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h1. Membrane thickness = 2 µm. Feed composition is 40% by weight of R32, 40% by weight of R125, 10% by weight of R600a, and 10% by weight of R290.

[0169] Table 4 illustrates an example of the membrane separation performance for the M2 mixture (membrane surface area: 5.1 m2)

[0170] Table 4

[0171] [Tables4] M2 retentate permeate Flow rate (kg / h) 10 4.8 5.2 Pressure (bar) 7.4 7.4 1.01 Refrigerant (% by weight) R32 40 12.7 65.0 R125 40 51.4 29.5 R290 10 17.4 3.3 R600a 10 18.5 2.2

[0172] As can be seen, the HC content in the product stream can be reduced from 20% by weight to 5.5% by weight with a single-stage membrane unit with a permeation area of ​​5 m² applying a feed pressure of 7.4 bar. The recovery and purity of R32+R125 are 61.4% and 94.5% by weight, respectively.

[0173] Table 5 illustrates another example of membrane separation performance for the M2 mixture (membrane area: 17 m2)

[0174] Table 5

[0175] [Tables5] M2 retentate permeate Flow rate (kg / h) 10 4.8 5.2 Pressure (bar) 3.6 3.6 1.01 Refrigerant (% by weight) R32 40 18.9 59.4 R125 40 47.4 33.2 R290 10 16.0 4.5 R600a 10 17.7 2.9

[0176] In this case, a much lower pressure of 3.6 bar must be applied in order to achieve an R32+R125 recovery and a purity of 60.2% and 92.6% by weight, respectively

[0177] Example 3: process employing a 2-stage membrane separation unit and hydrocarbons

[0178] In the two-stage design, the permeate from the first membrane unit is generally recompressed and sent to a second membrane unit, where further separation is performed. The final permeate is then enriched twice. Moreover, since the volume of gas processed by the second-stage membrane unit is smaller than in the first stage, the membrane surface area of ​​the second stage is smaller, and the required compression power does not increase significantly compared to the one-stage process. Filtration of the mixture (ml)

[0179] Figure 5 allows for a comparison of the purification of HFCs and HFOs using one and two steps. It illustrates the concentration of HFCs and HFOs in the permeate stream versus the recovery of HFCs and HFOs as a function of the feed pressure (1–8 bar) and the membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h₁. Membrane thickness = 2 µm. The feed composition is 90% by weight of HFCs and HFOs and 10% by weight of HC (R600a + R290).

[0180] As can be seen, this configuration improves the product specifications compared to the single-step process, as it would allow the presence of HC in the permeate stream to be reduced from the initial 10% by weight to a low hydrocarbon concentration (< 2% by weight) with HFC+HFO recoveries around 60%.

[0181] A schematic representation of a two-membrane separation unit The number of stages is shown in [Fig. 1]. The unit comprises two filtration modules connected in series, the first module having a membrane surface area of ​​57 m² and the second module having a membrane surface area of ​​5 m². The initial flow feeds the first module alone initially, then, as soon as it becomes available, the retentate from the second module is recycled to the inlet of the first module, adding to the initial flow and thus modifying the composition of the flow entering the first module. The results given in Table 6 illustrate an equilibrium situation.

[0182] Table 6

[0183] [Tableauxô] Initial flow (mL) Flow in the 1st module (= initial flow + recycled flow) Retentate of the 1st module Permeate of the 1st module (after recompression) Retentate of the 2nd module (= recycled flow) Permeate of the 2nd module Flow rate (kg / h) 10 23.6 3.7 19.9 13.6 6.3 Pressure (bar) 3.7 7.8 4.8 8 8 1.01 Refrigerant (% by weight) R32 16 10.1 2.9 11.5 5.8 23.8 R125 26 32.7 25.1 34.1 37.6 26.6 R134a 21 16.0 5.0 18.1 12.4 30.5 R1234yf 20 23.9 39.3 21.0 26.8 8.4 R1234ze 7 8.1 3.7 8.9 8.9 9.0 R290 5 5.3 11.3 4.1 5.4 1.3 R600a 5 3.9 12.7 2.3 3.1 0.4

[0184] As can be seen, it is possible to achieve a target HFC+HFO purity of 98.3% by weight with a recovery of 68.8%. The specifications of this product are obtained with a feed pressure of 4.8 bar at the first stage and 8 bar at the second stage, and with modules of 57 m² and 5 m² membrane surface area.

[0185] The initial hydrocarbon content of 10% by weight in the stream is less than 2% by weight in the second permeate (i.e. a decrease by a factor of 5). Filtration of mixture M2

[0186] Figure 6 allows for a comparison of the R32+R125 purification with one step and Two stages. It illustrates the concentration of R32+R125 in the permeate stream versus the recovery of R32+R125 as a function of feed pressure (1-8 bar) and membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h1. Membrane thickness = 2 µm. The feed composition is 40% by weight of R32, 40% by weight of R125, 10% by weight of R600a, and 10% by weight of R290.

[0187] The process illustrated in [Fig. 7] with recycling of the second retentate into the feed stream of the first module is also followed, with the difference that the membrane surface area is 80 m² in the first module and 5 m² in the second filtration module. The results at steady state are given in Table 7.

[0188] Table 7

[0189] [Tables7] M2 Initial flow Flow in the 1st module (= initial flow + recycled flow) Retentate of the 1st module Permeate of the 1st module (after recompression) Retentate of the 2nd module (= recycled flow) Permeate of the 2nd module Flow rate (kg / h) 10 22.3 4.7 17.6 12.3 5.3 Pressure (bar) 3.5 3.5 3.5 6.0 6.0 1.01 Refrigerant (% by weight) R32 40 29.5 11.5 34.34 21.0 65.3 R125 40 53.3 48.3 54.73 64.2 32.6 R290 10 9.7 19.5 7.02 9.4 1.6 R600a 10 7.5 20.7 3.91 5.4 0.5

[0190] As can be seen, the two-stage filtration step reduces the presence of HC from the initial 20% by weight to approximately 2% by weight (a tenfold reduction) and achieves a higher recovery level (65%) than the single-stage separation. This separation is carried out with two membrane units of 80 and 5 m², respectively. The recovery and purity of R32+R125 are 64.8% and 97.9% by weight, respectively.

[0191] Example 4: process employing a 2-membrane separation unit floors and a fluorinated contaminant.

[0192] In the two-stage design, the permeate from the first membrane unit is generally recompressed and sent to a second membrane unit, where further separation is performed. The final permeate is then enriched twice. Furthermore, since the volume of gas treated by the second-stage membrane unit is smaller than in the first stage, the membrane surface area of ​​the second stage is smaller, and the required compression power does not increase significantly compared to the one-stage process. When the contaminant is a fluorinated contaminant, it may be advantageous to isolate this fluorinated chemical compound, which is classified as a contaminant, for recycling as well. Filtration of the M3 mixture

[0193] Figure 7 allows for a comparison of the separation of the fluorinated chemical compound R227ea with one and two stages. It illustrates the concentration of R227ea in the permeate stream versus the recovery of R227ea as a function of the feed pressure (1-4 bar) and the membrane area. Each data point represents a combination of feed pressure and membrane area. Feed rate = 10 kg h₁. Membrane thickness = 2 µm. The feed composition is 70 wt% R227ea, 20 wt% R1234ze, and 10 wt% R134a.

[0194] The process illustrated in [Fig. 5] with recycling of the second retentate into the feed stream of the first module is also followed, with the difference that the membrane surface area is 15.3 m² in the first module and 21.8 m² in the second filtration module. The results at steady state are given in Table 8.

[0195] Table 8

[0196] [Tables8] M2 Initial flow Flow in the 1st module (= initial flow + recycled flow) Retentate of the 1st module Permeate of the 1st module Retentate of the 2nd module (= recycled flow) Permeate of the 2nd module Flow rate (kg / h) 10 15.7 11.3 4.4 5.6 5.7 Pressure (bar) 3.0 3.0 3.0 1.01 3.0 1.01 Refrigerant (% by weight) R227a 70 68.9 75.9 50.9 84.97 67.0 R134a 20 20.5 14.9 34.8 8.47 21.3 R1234ze 10 10.6 9.2 14.3 6.56 11.7

[0197] As can be seen, the two-stage filtration step allows for the recovery of the fluorinated chemical contaminant R227ea in the first and second retentates at 68% and 85% respectively. This contaminant can then be purified and recycled.

Claims

Demands

1. A process for recycling a mixture (1) comprising at least one fluorinated fluid characterized in that it comprises: - a) the supply, in the form of an initial stream (3), of a mixture (1) comprising at least one fluorinated fluid; the mixture comprising one or more fluorinated chemical components (41, 43, 49, 51, 55) and one or more contaminants selected from one or more hydrocarbons and / or one or more fluorinated contaminants; - b) membrane filtration of the initial stream (3) so as to obtain a purified stream (5) comprising a contaminant content lower than the contaminant content of the initial stream (3) and a contaminant-enriched stream (33); said membrane filtration comprising at least two successive membrane filtration substeps; and - c) the recovery of the purified stream (5) and / or the contaminant-enriched stream (33) for reuse and / or recycling.

2. The recycling process according to claim 1 characterized in that the initial stream (3) comprises one or more fluorinated contaminants and the or at least one fluorinated contaminant is 1,1,1,2,3,3,3-heptafluoropropane (R227ea) and / or in that the initial stream (3) comprises one or more fluorinated contaminants and step c) comprises the recovery of the contaminant-enriched stream (33) and its recycling.

3. The recycling process according to claim 1 or 2 characterized in that the initial stream (3) comprises one or more hydrocarbons selected from the group comprising propane and isobutane and / or in that the initial stream (3) comprises one or more hydrocarbons and step c) comprises the recovery of the purified stream (5) and its recycling.

4. The recycling process according to any one of claims 1 to 3, characterized in that step b) of membrane filtration comprises at least one substep of filtration using a membrane comprising at least one layer of a polymer material selected from a polyethersulfone, a polysulfone, a polyvinylidene fluoride, a co- polyether block polymer and polyamide block polymer, polypropylene, cellulose acetate, polytetrafluoroethylene, sulfonated polyphenylenesulfone, cellulose acetate butyrate, polyhedral oligomeric silsesquioxane, or polydimethylsiloxane.

5. The recycling process according to any one of claims 1 to 4 characterized in that step b) of membrane filtration comprises at least one substep of filtration using a membrane comprising at least one layer of a material chosen to be a copolymer of polyether blocks and polyamide blocks; preferably, the polyamide block comprises at least one polyamide chosen from polyamide 6, polyamide 11 and polyamide 12; preferably, polyamide 6.

6. The recycling process according to any one of claims 1 to 5, characterized in that the initial stream (3) comprises one or more fluorinated chemical components (41, 43, 49, 51, 55) selected from hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFOs), and hydrochlorofluoroolefins (HCFOs), and / or in that the initial stream (3) comprises one or more fluorinated fluids (41, 43, 49, 51, 55) selected from difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 2,3,3,3-tetrafluoropropene (R1234yf), and trans-1,3,3,3-tetrafluoroprop-1-ene (RI234ze).

7. The recycling process according to any one of claims 1 to 6 characterized in that the initial stream supplied in step a) comprises a hydrocarbon content greater than or equal to 0.5% by weight relative to the total weight of the initial stream (3), and / or in that step b) is conducted so as to obtain a hydrocarbon content less than 5.0% by weight relative to the total weight of the purified stream (5).

8. The recycling process according to any one of claims 1 to 7 characterized in that the initial stream (3) comprises at least two fluorinated chemical components (41, 43, 49, 51, 55) and in that step c) of recycling the purified stream (5) comprises the separation of said fluorinated chemical components (41, 43, 49, 51, 55) by distillation.

9. The recycling process according to claim 8, characterized in that the step of separating the fluorinated chemical components (41, 43, 49, 51, 55) by distillation comprises: - a sub-step of identifying, in the mixture of fluorinated chemical components (41, 43, 49, 51, 55), at least two sub- mixtures (39, 47, 53), each submixture being a simple submixture (53) comprising a single fluorinated chemical component (55) or a complex submixture (39, 47) comprising a combination of chemical components (41, 43, 49, 51), each complex submixture (39, 47) being associated either with a first secondary distillation group by a pressure balance distillation method, or with a second secondary distillation group by an extraction distillation method, - a primary distillation step, using a simple distillation column 15, so as to separate each identified submixture (39, 47, 53), - a secondary distillation step, by at least two auxiliary columns (17, 19, 21, 23), of each complex submixture (39, 47) of the first group and the second group,the complex submixtures (39) of the first group being separated by the pressure balance distillation method and the complex submixtures (47) of the second group being separated, by means of a solvent (45), by the extraction distillation method.

10. Installation for implementing the process of recycling a mixture (1) comprising at least one fluorinated fluid according to any one of claims 1 to 9, characterized in that it comprises a membrane filtration unit (7) comprising at least two membrane filtration modules (9, 11) arranged in series.

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