Method for producing a recycled refrigerant composition containing (E)-1,2-difluoroethylene

Abstract

The present invention provides a method for producing a recycled refrigerant composition in which disproportionation of the resulting recycled refrigerant composition is suppressed compared to conventional methods, and the generation of acid due to the reaction between the refrigerant composition and oxygen is also suppressed. [Solution] A method for producing a recycled refrigerant composition containing (E)-1,2-difluoroethylene, The process includes step 1 of removing oxygen and water from the mixed refrigerant composition to be treated, which contains (E)-1,2-difluoroethylene. The above step 1 is carried out under a pressure of 5 MPa·G or less. A manufacturing method characterized by the following features.

Description

Technical Field

[0006]

[0001] The present disclosure relates to a method for producing a recycled refrigerant composition containing (E)-1,2-difluoroethylene.

Background Art

[0002] (E)-1,2-Difluoroethylene (hereinafter also referred to as "R-1132(E)") has a low global warming potential (GWP), and thus is attracting attention as a refrigerant to replace difluoromethane (R-32) and 1,1,1,2,2-pentafluoroethane (R-125), which are greenhouse gases.

[0003] Patent Document 1 discloses a method for recycling a refrigerant, which includes a step of transferring an un-recycled refrigerant composition containing one or more hydrofluoroolefins from a supply container to a treatment container, a step of determining a target composition, a step of determining one or more treatments based on the target composition, and a step of performing at least one treatment selected from the group consisting of transfer, blend, distillation, nitrogen purge, filtration, dehydration, caustic scrub, decant, and combinations thereof to form a partially recycled refrigerant composition or a recycled refrigerant composition.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a method for producing a recycled refrigerant composition in which disproportionation of the obtained recycled refrigerant composition is suppressed more than in the conventional method, and generation of an acid due to reaction between the refrigerant composition and oxygen is suppressed.

Means for Solving the Problems

[0006] This disclosure includes, for example, the disclosures described in the following sections: 1. A method for producing a recycled refrigerant composition containing (E)-1,2-difluoroethylene, comprising step 1 of removing oxygen and water from the mixed refrigerant composition to be treated containing (E)-1,2-difluoroethylene, The above step 1 is carried out under a pressure of 5 MPa·G or less. A manufacturing method characterized by the following features. 2. The manufacturing method according to item 1, wherein step 1 is a step of passing the mixed refrigerant composition to be treated through an adsorption tower containing at least one dehydrating agent, the dehydrating agent being at least one selected from the group consisting of zeolite, silica gel, calcium chloride, and sodium sulfate. 3. The manufacturing method according to item 1 or 2, wherein the method for removing oxygen in step 1 is to pass the mixed refrigerant composition to be treated through the adsorption column containing an oxygen scavenger, and / or to remove oxygen using a distillation column. 4. The manufacturing method according to item 3, wherein the oxygen scavenger is at least one selected from the group consisting of metals, metal oxides, and organic oxygen scavengers. 5. The manufacturing method according to any one of items 1 to 4, wherein step 1 is carried out under a pressure of 0.05 MPa·G or higher. 6. The manufacturing method according to any one of items 1 to 5, wherein step 1 is carried out under temperature conditions of 150°C or lower. 7. The manufacturing method according to any one of items 1 to 6, wherein the content of (E)-1,2-difluoroethylene in the mixed refrigerant composition to be treated is greater than 70% by mass and less than or equal to 100% by mass, with the total content of refrigerants in the mixed refrigerant composition to be treated being 100% by mass, and step 1 is carried out under a pressure of 1.5 MPa·G or less and a temperature of 150°C or less. 8. The manufacturing method according to any one of items 1 to 6, wherein the content of (E)-1,2-difluoroethylene in the mixed refrigerant composition to be treated is greater than 50% by mass and 70% by mass or less, with the total content of refrigerants in the mixed refrigerant composition to be treated being 100% by mass, and step 1 is carried out under a pressure of 3 MPa·G or less and a temperature of 150°C or less. 9. The manufacturing method according to any one of items 1 to 6, wherein the content of (E)-1,2-difluoroethylene in the mixed refrigerant composition to be treated is 50% by mass or less, with the total content of refrigerants in the mixed refrigerant composition to be treated being 100% by mass, and step 1 is carried out under a pressure of 5 MPa·G or less and a temperature of 150°C or less. 10. The manufacturing method according to any one of items 1 to 9, wherein in step 1, the material is further passed through an adsorption tower containing a deoxidizing agent. 11. A manufacturing method according to any one of items 1 to 10, further comprising step 2 of aggregating the recycled refrigerant composition. [Effects of the Invention]

[0007] The method for producing a recycled refrigerant composition according to this disclosure suppresses disproportionation of the resulting recycled refrigerant composition compared to conventional methods, and also suppresses the generation of acid due to the reaction between the refrigerant composition and oxygen. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the steps of the manufacturing method disclosed herein. [Modes for carrying out the invention]

[0009] In this specification, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0010] In this specification, the term "refrigerant" includes at least compounds that have been assigned a refrigerant number (ASHRAE number) beginning with R, as defined by ISO 817 (International Organization for Standardization), and also includes compounds that have equivalent refrigerant properties even if they have not yet been assigned a refrigerant number. Refrigerants are broadly classified into "fluorocarbon compounds" and "non-fluorocarbon compounds" in terms of their compound structure. "Fluorocarbon compounds" include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Examples of "non-fluorocarbon compounds" include propane (R290), propylene (R1270), butane (R600), isobutane (R600a), carbon dioxide (R744), and ammonia (R717).

[0011] A composition containing a refrigerant includes at least (1) the refrigerant itself (including a mixture of refrigerants), (2) a composition further containing other components that can be used to obtain a working fluid for a refrigerator by mixing with at least refrigerant oil, and (3) a working fluid for a refrigerator containing refrigerant oil. In this specification, of these three embodiments, composition (2) is referred to as "refrigerant composition" to distinguish it from the refrigerant itself (including a mixture of refrigerants). In the manufacturing method of this disclosure, the mixed refrigerant composition to be treated, which is recovered in the market, etc., and used as a raw material gas, may contain oil such as the refrigerant oil mentioned above.

[0012] The present disclosure provides a method for producing a recycled refrigerant composition containing (E)-1,2-difluoroethylene, comprising step 1 of removing oxygen and water from the mixed refrigerant composition to be treated containing (E)-1,2-difluoroethylene, wherein step 1 is carried out under a pressure of 5 MPa·G or less.

[0013] The manufacturing method of this disclosure includes step 1, which removes oxygen and water from the used, recovered mixed refrigerant composition to be treated, thereby enabling the production of a recycled refrigerant composition containing (E)-1,2-difluoroethylene (R-1132(E)), and enabling the production of a recycled refrigerant composition containing R-1132(E). Furthermore, in the manufacturing method of this disclosure, step 1 is carried out under a pressure of 5 MPa·G or less, thus suppressing disproportionation. In addition, the manufacturing method of this disclosure can suppress the generation of acid due to the reaction between the refrigerant composition and oxygen.

[0014] The manufacturing method disclosed herein enables refrigerant regeneration. In this specification, refrigerant regeneration means reprocessing to remove oil, water, acidic substances, and other impurities that may adversely affect the quality of the refrigerant, i.e., the performance of the refrigerant.

[0015] The recycled refrigerant compositions produced by the manufacturing method of this disclosure are refrigerant compositions obtained by regenerating used (or recovered) treated mixed refrigerants to meet the AHRI 700 quality standard. The quality of the refrigerant can be verified by analytical techniques such as GC-FID, GC-TCD GC-MS, FTIR, Goetz Bub, Karl Fischer, Byk-Garner Color, and various other analytical methods.

[0016] (Process 1) The mixed refrigerant composition to be treated used in step 1 of the manufacturing method of this disclosure is a mixed refrigerant composition to be treated (raw material gas) recovered in the market, etc. The lower limit of the R-1132(E) content in the raw material gas is not particularly limited, and can be 0.1% by mass or more, 1% by mass or more, 10% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 70% by mass or more, with the raw material gas being 100% by mass. Furthermore, the upper limit of the R-1132(E) content in the raw material gas is not particularly limited, and can be 100% by mass or less, 99.9% by mass or less, or 99.5% by mass or less, with the raw material gas being 100% by mass.

[0017] In the manufacturing method of the present disclosure, Step 1 is carried out under a pressure of 5 MPa·G or less. If the pressure exceeds 5 MPa, disproportionation of the produced recycled refrigerant composition cannot be suppressed. The pressure is preferably 4 MPa or less, more preferably 3 MPa or less, still more preferably 1 MPa or less, and particularly preferably 0.5 MPa or less. Also, the lower limit of the pressure is not particularly limited, and is preferably 0.01 MPa or more, more preferably 0.03 MPa or more, and still more preferably 0.05 MPa or more. By having the lower limit of the pressure within the above range, gas entrainment from the outside into the reaction system can be suppressed.

[0018] In this specification, the pressure means gauge pressure.

[0019] In the manufacturing method of the present disclosure, the temperature conditions when carrying out Step 1 are preferably 200°C or less, more preferably 150°C or less, and still more preferably 100°C or less. By having the upper limit of the temperature conditions within the above range, disproportionation of the produced recycled refrigerant composition can be more effectively suppressed. Also, the temperature conditions when carrying out Step 1 are preferably -53°C or more, more preferably 0°C or more, and still more preferably a temperature condition exceeding 0°C. When the lower limit of the temperature conditions is within the above range, since the mixed refrigerant composition to be treated is in a liquid or gaseous state, Step 1 becomes easier, which is desirable. When the upper limit of the temperature conditions is within the above range, disproportionation can be further suppressed.

[0020] In the manufacturing method of the present disclosure, suitable pressure conditions and temperature conditions in Step 1 may be set according to the content range of R-1132(E) in the mixed refrigerant composition to be treated. Hereinafter, an explanation will be given according to the content range of R-1132(E) in the mixed refrigerant composition to be treated. In each of the following cases (1) to (3), the content of (E)-1,2-difluoroethylene is the content with the total content of the refrigerants in the mixed refrigerant composition to be treated being 100% by mass. The above refrigerants mean, for example, R-1132(E), R-1234yf, etc., and is a concept that does not include impurities such as oil content contained in the mixed refrigerant composition to be treated.

[0021] ((1) Content of R-1132(E): More than 7 mass% and 100 mass% or less) When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 70% by mass and less than or equal to 100% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the pressure conditions in step 1 are preferably 1.5 MPa·G or less, more preferably 1 MPa·G or less, and even more preferably 0.5 MPa·G or less. In this case, the lower limit of the pressure conditions in step 1 is not particularly limited and may be 0.01 MPa or more, 0.03 MPa or more, or 0.05 MPa or more. When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 70% by mass and less than or equal to 100% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the disproportionation of the resulting regenerated refrigerant composition is further suppressed by the pressure conditions in step 1 being within the above range, and the generation of acid due to the reaction between the refrigerant composition and oxygen is further suppressed.

[0022] When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 70% by mass and less than or equal to 100% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the temperature conditions for step 1 are preferably 150°C or lower, more preferably 100°C or lower, and even more preferably 50°C or lower. In this case, the upper limit of the temperature conditions for step 1 is not particularly limited and may be around 200°C or lower. In this case, the lower limit of the temperature conditions for step 1 is not particularly limited and may be -79°C or higher, -30°C or higher, 0°C or higher, or 20°C or higher. When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 70% by mass and less than or equal to 100% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the disproportionation of the resulting regenerated refrigerant composition is further suppressed by the temperature conditions for step 1 being within the above range, and the generation of acid due to the reaction between the refrigerant composition and oxygen is further suppressed.

[0023] ((2) R-1132(E) content: more than 50% by mass and not more than 70% by mass) When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 50% by mass and less than or equal to 70% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the pressure condition in step 1 is preferably 3 MPa·G or less, and more preferably 2 MPa·G or less. In this case, the lower limit of the pressure condition in step 1 is not particularly limited and may be 0.01 MPa or more, 0.03 MPa or more, or 0.05 MPa or more. When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 50% by mass and less than or equal to 70% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the disproportionation of the resulting regenerated refrigerant composition is further suppressed by the pressure condition in step 1 being within the above range, and the generation of acid due to the reaction between the refrigerant composition and oxygen is further suppressed.

[0024] When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 50% by mass and less than or equal to 70% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the temperature condition of step 1 is preferably 150°C or lower, and more preferably 100°C or lower. In this case, the upper limit of the temperature condition of step 1 is not particularly limited and may be around 200°C or lower. In this case, the lower limit of the temperature condition of step 1 is not particularly limited and may be -79°C or higher, -30°C or higher, 0°C or higher, or 20°C or higher. When the R-1132(E) content in the mixed refrigerant composition to be treated is greater than 50% by mass and less than or equal to 70% by mass, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the disproportionation of the resulting regenerated refrigerant composition is further suppressed by the temperature condition of step 1 being within the above range, and the generation of acid due to the reaction between the refrigerant composition and oxygen is further suppressed.

[0025] ((3) R-1132(E) content: 50% by mass or less) When the R-1132(E) content in the mixed refrigerant composition to be treated is 50% by mass or less, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the pressure condition in step 1 is preferably 5 MPa·G or less, and more preferably 4 MPa·G or less. In this case, the lower limit of the pressure condition in step 1 is not particularly limited and may be 0.01 MPa or more, 0.03 MPa or more, or 0.05 MPa or more. When the R-1132(E) content in the mixed refrigerant composition to be treated is 50% by mass or less, with the total refrigerant content in the mixed refrigerant composition to be treated being 100% by mass, the disproportionation of the resulting regenerated refrigerant composition is further suppressed by setting the pressure condition in step 1 within the above range, and the generation of acid due to the reaction between the refrigerant composition and oxygen is further suppressed.

[0026] When the R-1132(E) content in the mixed refrigerant composition to be treated is 50% by mass or less, based on 100% by mass of the total refrigerant content in the mixed refrigerant composition to be treated, the temperature condition for step 1 is preferably 150°C or lower. In this case, the upper limit of the temperature condition for step 1 is not particularly limited and should be around 200°C or lower. In this case, the lower limit of the temperature condition for step 1 is not particularly limited and may be -79°C or higher, -30°C or higher, 0°C or higher, or 20°C or higher. When the R-1132(E) content in the mixed refrigerant composition to be treated is 50% by mass or less, based on 100% by mass of the total refrigerant content in the mixed refrigerant composition to be treated, the disproportionation of the resulting regenerated refrigerant composition is further suppressed by setting the temperature condition for step 1 within the above range, and the generation of acid due to the reaction between the refrigerant composition and oxygen is further suppressed.

[0027] In step 1, oxygen and water are removed from the mixed refrigerant composition to be treated. In step 1, it is preferable that the oxygen is removed from the mixed refrigerant composition by passing it through an adsorption tower containing at least a dehydrating agent.

[0028] The dehydrating agent is not particularly limited, and can be zeolite, silica gel, calcium chloride, sodium sulfate, etc. Among these, zeolite is preferred from the viewpoint of superior dehydration performance.

[0029] Dehydrating agents may be used individually or in mixtures of two or more types.

[0030] When the adsorption tower capacity is approximately 50-100cc, the amount of dehydrating agent used is preferably 10-60g, and more preferably 20-50g. By keeping the lower limit of the dehydrating agent usage within the above range, the dehydration of the regenerated refrigerant composition is more sufficient. By keeping the upper limit of the dehydrating agent usage within the above range, the gas flow in the reaction apparatus is improved, and production efficiency is further enhanced.

[0031] In this specification, if an adsorption tower contains only a dehydrating agent and does not contain oxygen scavengers, deoxidizing agents, etc., as described later, the adsorption tower will also be referred to as a "dehydration tower."

[0032] The method for removing oxygen from the mixed refrigerant composition to be treated is not particularly limited, and examples include adding the mixed refrigerant composition to the above-mentioned dehydrating agent and then passing it through an adsorption column containing an oxygen scavenger, or removing oxygen by utilizing the difference between the boiling point of the mixed refrigerant composition and the boiling point of oxygen. Examples of methods for removing oxygen by utilizing the difference between the boiling point of the mixed refrigerant composition and the boiling point of oxygen include removing oxygen using a distillation column, or cooling the mixed refrigerant composition to be treated to a liquid or solid and removing gaseous oxygen. These methods may be used individually or in combination of two or more.

[0033] The oxygen scavenger is not particularly limited and can be a metal, metal oxide, metal salt, organic oxygen scavenger, sulfate, etc.

[0034] Examples of the above-mentioned metals include iron, and iron powder can be suitably used.

[0035] Examples of the above-mentioned metal oxides include metal oxides other than those used as dehydrating agents, and specifically, triiron tetroxide can be used.

[0036] Examples of the above-mentioned organic oxygen absorbers include vitamin C.

[0037] When the adsorption tower capacity is approximately 50-100cc, the amount of oxygen scavenger used is preferably 10-60g, and more preferably 20-50g. By keeping the lower limit of the oxygen scavenger usage within this range, the removal of oxygen from the regenerated refrigerant composition becomes more sufficient. By keeping the upper limit of the oxygen scavenger usage within this range, the gas flow in the reaction apparatus improves, leading to increased production efficiency.

[0038] When an adsorption tower is used in the manufacturing method of this disclosure, the adsorption tower may contain other additives such as polymerization inhibitors and stabilizers in addition to the dehydrating agent and oxygen scavenger described above. When an adsorption tower is used in the manufacturing method of this disclosure, one adsorption tower may contain other additives such as dehydrating agents, oxygen scavengers, polymerization inhibitors, and stabilizers, and multiple adsorption towers containing these separately may be connected in series. Furthermore, multiple adsorption towers containing a combination of several of the other additives such as dehydrating agents, oxygen scavengers, polymerization inhibitors, and stabilizers may be connected in series. The above-mentioned polymerization inhibitors, stabilizers, and other additives may be used by being contained in the adsorption tower, or they may be used by being added to the mixed refrigerant composition to be treated.

[0039] Limonene, terpenes, etc., can be used as polymerization inhibitors. By adding a polymerization inhibitor to the adsorption tower, the dehydrating agent and oxygen scavenging agent can be regenerated. The polymerization inhibitor may be used by being incorporated into the adsorption tower, or by being added to the mixed refrigerant composition to be treated. When a polymerization inhibitor is used as described above, the polymerization inhibitor that has eluted from the adsorption tower into the mixed refrigerant composition to be treated, or the polymerization inhibitor that has been added to the mixed refrigerant composition to be treated, will be mixed into the mixed refrigerant composition to be treated. However, by connecting an adsorption tower containing silica gel, the polymerization inhibitor mixed into the mixed refrigerant composition to be treated can be removed. It is preferable that the adsorption tower containing silica gel is connected after the adsorption tower containing the polymerization inhibitor. The polymerization inhibitor may be used by being incorporated into the adsorption tower, or by being added to the mixed refrigerant composition to be treated.

[0040] Dibutylhydroxytoluene (BHT), butylhydroxyanisole (BHA), etc., can be used as stabilizers. When the mixed refrigerant composition to be treated passes through the adsorption tower, R-1132(E) may polymerize or decompose due to the effects of the dehydrating agent, oxygen scavenger, and other additives. By adding a stabilizer to the adsorption tower, the polymerization and decomposition of R-1132(E) can be suppressed. The stabilizer may be used as part of the composition contained in the adsorption tower, or it may be used by adding it to the mixed refrigerant composition to be treated.

[0041] In the manufacturing method of this disclosure, oxygen may be removed from the mixed refrigerant composition to be treated by a distillation column. The distillation column is not particularly limited, and any known distillation column can be used.

[0042] The distillation temperature when removing oxygen using a distillation column is preferably 50 to 250°C, more preferably 80 to 200°C, even more preferably 100 to 180°C, and particularly preferably 130 to 170°C.

[0043] In the manufacturing method of this disclosure, the adsorption tower may further contain a deoxidizing agent. By containing a deoxidizing agent in the adsorption tower, acidic components generated by the reaction of R-1132(E) in the refrigerant mixture to be treated with oxygen in the air mixed into the refrigerant mixture to be treated can be removed simultaneously when water is removed by the adsorption tower.

[0044] The deoxidizing agent is not particularly limited, and soda lime, sodium hydroxide, potassium hydroxide, etc., can be used. Among these, soda lime is preferred from the viewpoint of being able to remove acidic components more easily.

[0045] When the adsorption tower capacity is approximately 50-100cc, the amount of deoxidizing agent used is preferably 10-60g, and more preferably 20-50g. By keeping the lower limit of the deoxidizing agent usage within this range, the removal of acidic components from the recycled refrigerant composition becomes more sufficient. By keeping the upper limit of the deoxidizing agent usage within this range, the gas flow in the reaction apparatus improves, leading to increased production efficiency.

[0046] The deoxidizing agent may be contained in an adsorption tower that also contains a dehydrating agent and an oxygen scavenger, or it may be incorporated into a separate adsorption tower within the reaction system and contained in that separate adsorption tower.

[0047] When the deoxidizing agent is contained in an adsorption tower separate from the adsorption tower containing the dehydrating agent and the oxygen scavenger, it is preferable to install the adsorption tower containing the deoxidizing agent before the adsorption tower containing the dehydrating agent and the oxygen scavenger. With this configuration, the deoxidizing agent can be captured in the adsorption tower containing the dehydrating agent and the oxygen scavenger, and the deoxidizing agent can be removed from the regenerated refrigerant composition produced.

[0048] By step 1 described above, a recycled refrigerant composition containing (E)-1,2-difluoroethylene can be produced.

[0049] (cooling process) Step 1 may include a cooling step before Step 2, which will be described later, in which the obtained recycled refrigerant composition is cooled to obtain a liquefied or solidified recycled refrigerant composition. By including a cooling step in Step 1, the manufactured recycled refrigerant composition can be recovered more efficiently.

[0050] The cooling method for cooling the regenerated refrigerant composition is not particularly limited. For example, as shown in Figure 1, the mixed refrigerant composition to be treated is passed through an adsorption tower 12 containing a dehydrating agent and an oxygen scavenging agent to produce a regenerated refrigerant composition, and the regenerated refrigerant composition is recovered in a cylinder 13 immersed in a cooling container filled with liquid nitrogen 14 as a refrigerant.

[0051] The lower limit of the cooling temperature in the cooling process is preferably -230°C or higher, and more preferably -210°C or higher. The upper limit of the cooling temperature in the cooling process is preferably 50°C or lower, 25°C or lower, 0°C or lower, -50°C or lower, -100°C or lower, -150°C or lower, and -170°C or lower. By keeping the cooling temperature within the above range, the recycled refrigerant composition produced by the manufacturing method of this disclosure can be recovered more efficiently.

[0052] If step 1 includes a cooling step, the manufacturing method of the present disclosure may remove oxygen by performing a degassing operation in the cylinder used in the cooling step. That is, as shown in Figure 1, when recovering the regenerated refrigerant composition into a cylinder 13 immersed in a cooling container filled with liquid nitrogen 14 as a refrigerant, a degassing operation may be performed in the cylinder 13.

[0053] By step 1 described above, oxygen and water can be removed from the mixed refrigerant composition to be treated, which contains (E)-1,2-difluoroethylene.

[0054] (Process 2) The manufacturing method of the present disclosure may further include a step 2 after step 1 in which the recycled refrigerant composition is aggregated. By including step 2 in the manufacturing method of the present disclosure, the manufactured recycled refrigerant composition can be aggregated into an aggregation container with a larger capacity.

[0055] The method for aggregating the recycled refrigerant composition is not particularly limited. The recycled refrigerant composition can be aggregated into the aggregating container by connecting the container containing the recycled refrigerant composition obtained in step 1 to a larger aggregating container and reducing the pressure.

[0056] In step 2, the aggregation container is preferably cooled by immersion in an ice bath. The cooling temperature is preferably -10°C to 10°C, and more preferably -5°C to 5°C. By keeping the cooling temperature within the above range, the recycled refrigerant composition can be aggregated more stably within the aggregation container.

[0057] According to the manufacturing method of the present disclosure described above, a mixed refrigerant composition to be treated, recovered from the market, can be recycled to produce a recycled refrigerant composition containing (E)-1,2-difluoroethylene. The recycled refrigerant composition produced by the manufacturing method of the present disclosure has a low global warming potential (GWP) and can be suitably used as a substitute refrigerant for difluoromethane (R-32) and 1,1,1,2,2-pentafluoroethane (R-125), which are greenhouse gases. According to the manufacturing method of the present disclosure, disproportionation of the recycled refrigerant composition produced is suppressed, and the generation of acid due to the reaction between the refrigerant composition and oxygen can be suppressed, so a recycled refrigerant composition containing (E)-1,2-difluoroethylene can be suitably produced. [Examples]

[0058] The present disclosure will be described in more detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

[0059] (Example 1) A recycled refrigerant composition containing (E)-1,2-difluoroethylene was produced using a manufacturing apparatus similar to the one shown in Figure 1. Specifically, a container 11 containing the mixed refrigerant composition to be treated, recovered from the market, was prepared and connected to the manufacturing apparatus. Next, the mixed refrigerant composition to be treated, which was in gaseous phase, was fed into the manufacturing apparatus and passed through an adsorption tower 12 containing a deoxidizing agent and a dehydrating agent to remove water and acid. The mixed refrigerant composition to be treated was recovered in a cylinder 13 immersed in a cooling container filled with liquid nitrogen 14 as a refrigerant. Next, oxygen was removed from the mixed refrigerant composition to be treated by performing a degassing operation in the cylinder 13, thereby producing a recycled refrigerant composition.

[0060] The regenerated refrigerant composition containing (E)-1,2-difluoroethylene was manufactured under the following conditions. Although Figure 1 shows an example where one adsorption tower 12 is provided, in Example 1, the mixed refrigerant composition to be treated was passed through a deoxidation tower from the supply side, and then through a dewatering tower connected in series with the deoxidation tower. • Pressure within the reaction system: 0.05~0.1 MPa·G • Temperature in the reaction system: 23°C • Cylinder degassing operation: 1 time / 100g ·Deoxidizing tower: Capacity 68cc • Deoxidizing agent: Soda lime, 43g filling amount ·Deoxidizing tower passing rate 5g / min • Dehydration tower: Capacity 68cc, dehydrating agent MS (molecular sieve (zeolite)), filling amount 43g MS regeneration conditions: 150°C reduced pressure, regeneration time 3 hours or more • Dehydration tower flow rate: 5g / min, moisture content reduced from 282ppm to 8ppm

[0061] (Example 2) The mixed refrigerant composition to be treated, which is in gaseous phase, was fed into the manufacturing apparatus and passed through an adsorption tower (dehydration tower) 12 containing a dehydrating agent but not an oxygen scavenger. Next, the mixed refrigerant composition to be treated was passed through a distillation tower after the adsorption tower (dehydration tower) 12 to remove oxygen. A regenerated refrigerant composition containing (E)-1,2-difluoroethylene was produced in the same manner as in Example 1.

[0062] The regenerated refrigerant composition containing (E)-1,2-difluoroethylene in the above-mentioned distillation column was produced under the following conditions. ·Dehydration tower passing amount: 80g / min • Dehydration tower pressure: 0.4~0.6 MPa·G • Dehydration tower temperature: 2-6℃ • Distillation temperature: 35℃

[0063] (Evaluation method) The recycled refrigerant compositions obtained in the examples were evaluated as follows.

[0064] (Composition of recycled refrigerant composition) The composition of the recycled refrigerant was analyzed using gas chromatography (MS detector).

[0065] (moisture) The moisture content in the recycled refrigerant composition was measured using a Karl Fischer moisture analyzer.

[0066] (acid content) The acidity was measured by immersing pH test paper in the recycled refrigerant composition.

[0067] (Oxygen concentration) The oxygen concentration of the recycled refrigerant composition was measured using an oxygen concentration meter.

[0068] (Evaporation residue) The evaporation residue of refrigerant oil and other components in the recycled refrigerant composition was measured according to the AHRI 700 standard.

[0069] The results are shown in Table 1.

[0070] [Table 1]

[0071] The results in Table 1 show that in Examples 1 and 2, the water content, evaporation residue (refrigerant oil, etc.), acid content, and oxygen content in the regenerated refrigerant composition were lower than those in the mixed refrigerant composition before regeneration, indicating that a regenerated refrigerant composition could be produced.

[0072] Furthermore, the results in Table 1 show that disproportionation was suppressed in Examples 1 and 2. In addition, it was found that in Example 1, the generation of acid due to the reaction between the refrigerant composition and oxygen was suppressed, and in Example 2, oxygen was removed, and the generation of acid was suppressed. [Explanation of Symbols]

[0073] 11: Container containing the mixed refrigerant composition to be treated 12:Adsorption tower 13: Cylinder 14: Liquid nitrogen

Claims

1. A method for producing a recycled refrigerant composition containing (E)-1,2-difluoroethylene, The process includes step 1 of removing oxygen and water from the mixed refrigerant composition to be treated, which contains (E)-1,2-difluoroethylene. The above step 1 is carried out under a pressure of 5 MPa·G or less. A manufacturing method characterized by the following features.

2. The manufacturing method according to claim 1, wherein step 1 is a step of passing the mixed refrigerant composition to be treated through an adsorption tower containing at least one dehydrating agent, the dehydrating agent being at least one selected from the group consisting of zeolite, silica gel, calcium chloride, and sodium sulfate.

3. The manufacturing method according to claim 2, wherein the method for removing oxygen in step 1 is to pass the mixed refrigerant composition to be treated through the adsorption column containing an oxygen scavenger, and / or to remove oxygen using a distillation column.

4. The manufacturing method according to claim 3, wherein the oxygen scavenger is at least one selected from the group consisting of metals, metal oxides, and organic oxygen scavengers.

5. The manufacturing method according to claim 1, wherein step 1 is carried out under a pressure of 0.05 MPa·G or higher.

6. The manufacturing method according to claim 1, wherein step 1 is carried out under temperature conditions of 150°C or lower.

7. The manufacturing method according to claim 1, wherein the content of (E)-1,2-difluoroethylene in the mixed refrigerant composition to be treated is greater than 70% by mass and less than or equal to 100% by mass, with the total content of refrigerants in the mixed refrigerant composition to be treated being 100% by mass, and step 1 is carried out under a pressure of 1.5 MPa·G or less and a temperature of 150°C or less.

8. The manufacturing method according to claim 1, wherein the content of (E)-1,2-difluoroethylene in the mixed refrigerant composition to be treated is more than 50% by mass and 70% by mass or less, with the total content of refrigerants in the mixed refrigerant composition to be treated being 100% by mass, and step 1 is carried out under a pressure of 3 MPa·G or less and a temperature of 150°C or less.

9. The manufacturing method according to claim 1, wherein the content of (E)-1,2-difluoroethylene in the mixed refrigerant composition to be treated is 50% by mass or less, with the total content of refrigerants in the mixed refrigerant composition to be treated being 100% by mass, and step 1 is carried out under a pressure of 5 MPa·G or less and a temperature of 150°C or less.

10. The manufacturing method according to claim 1, further comprising passing the material through an adsorption tower containing a deoxidizing agent in step 1.

11. Furthermore, the manufacturing method according to claim 1, further comprising step 2 of aggregating the recycled refrigerant composition.

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