HFC mixed refrigerant component separation and recovery apparatus and component separation and recovery method using HFC mixed refrigerant component separation and recovery apparatus

Abstract

The present invention provides a component separation and recovery apparatus for HFC mixed refrigerants that can separate R410A into R125 and R32 without temperature adjustment. [Solution] A component separation and recovery device for HFC mixed refrigerants, comprising: an R410A filled container 2, an R32 recovery container 3, and an R125 recovery container 4; an R32 recovery pipe 31 connected to the R410A filled container 2 and a filter unit 1, having an R410A supply valve SV1, an expansion valve 22, an evaporator 23, and an R410A compressor 5 in its path; an R32 recovery pipe 31 connected to the filter unit 1 and an R32 recovery container 3, having an R32 buffer tank 34 and an R32 compressor 6 in its path; a filter-impermeable gas pipe 11 connected to the filter unit 1; an R125 recovery pipe 41 branching from the filter-impermeable gas pipe 11 and connected to the R125 recovery container 4; and an R410A circulation pipe 71 branching from the filter-impermeable gas pipe 11 and connected between the R410A supply valve SV1 and the expansion valve 22 of the R410A supply pipe.

Description

Technical Field

[0001] The present invention relates to a component separation and recovery device for HFC (hydrofluorocarbon) mixed refrigerants used in thermal control systems such as air-conditioning equipment and heat pump systems, and is particularly specialized in the component separation and recovery of R410A refrigerant. More specifically, it relates to a component separation and recovery device for HFC mixed refrigerants and a component separation and recovery method using the same, for efficiently separating and recovering pentafluoroethane (R125) and difluoromethane (R32) constituting R410A.

Background Art

[0002] R410A has a zero ozone depletion potential (ODP) and is superior to R22 from the perspective of ozone layer protection. Therefore, it has been widely used as a standard UFC mixed refrigerant in thermal control systems such as air-conditioning equipment and heat pump systems. When disposing of equipment using these R410A, R410A is recovered and recycled. However, when recycling is not possible, it is rendered harmless by high-temperature incineration or chemical decomposition and then disposed of, but these treatments have a greater environmental impact compared to recycling. In addition, fluorite (calcium fluoride), which is a raw material for fluorocarbons, is unevenly distributed among producing countries and the demand in other industries is also increasing. Therefore, it is required in the future to recycle R410A as much as possible without performing disposal.

[0003] On the other hand, as the global warming problem becomes more serious, in recent years, the environmental impact of refrigerants used in heat treatment systems has attracted international attention. In particular, the global warming potential (GWP) of refrigerants has become an important indicator, and the reduction of the use of high-GWP refrigerants has become a global issue.

[0004] R410A is an HFC mixed refrigerant obtained by mixing pentafluoroethane (R125) and difluoromethane (R32) in equal amounts, and its GWP value is relatively high at about 2088, which has become a major current environmental problem. R125 and R32, both included in R410A, show a significant difference in their GWP values. R125 has a GWP value of 3500, indicating a large long-term impact on climate change. On the other hand, R32 has a GWP value of 675, which is significantly lower than R125, resulting in a relatively smaller environmental impact. Thus, since R32 has a significantly lower GWP value than R125, separating and recovering them would offer various environmental benefits. R32 could be reused as a low-GWP refrigerant, while R125 could be properly treated or repurposed for more environmentally friendly applications.

[0005] Patent Document 1 describes a method for recovering a specific fluorocarbon from recovered fluorocarbons that contain two or more types of fluorocarbons. Furthermore, Patent Documents 2 and 3 describe methods for separating a target gas from multiple types of gases. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2005-9715 [Patent Document 2] Japanese Patent Publication No. 2016-67972 [Patent Document 3] Japanese Patent Publication No. 2017-196601 [Overview of the project] [Problems that the invention aims to solve]

[0007] The method described in Patent Document 1 separates and recovers fluorocarbons contained in recovered fluorocarbons by utilizing differences in boiling points. However, R410A is an azeotropic mixture of R125 and R32, making separation by distillation using differences in boiling points difficult.

[0008] Furthermore, Patent Documents 2 and 3 describe a method of separating and recovering gases by changing the molecular size of each gas through a porous material filter, thereby altering the molecular size of each gas. However, since R410A is stored in a liquid state in a high-pressure gas container, it is difficult to control the temperature of the stored R410A. Moreover, a temperature control device is required to control the temperature. It should be noted that neither Patent Documents 2 nor 3 describes any specific means for temperature control.

[0009] The present invention aims to provide a component separation and recovery apparatus for HFC mixed refrigerants and a component separation and recovery method using the HFC mixed refrigerant component separation and recovery apparatus, which can separate R410A into R125 and R32 without temperature control. [Means for solving the problem]

[0010] The present invention, made to achieve the above objective, comprises an R410A-filled container filled with R410A, an R32 recovery container for recovering R32 separated from R410A, an R125 recovery container for recovering R125 separated from R410A, an R410A supply pipe connected to the R410A-filled container and a filter unit, having an R410A supply valve, an expansion valve, an evaporator, and an R410A compressor in its path, an R32 recovery pipe connected to the filter unit and the R32 recovery container, having an R32 buffer tank and an R32 compressor in its path, a filter-impermeable gas pipe connected to the filter unit, and a branch from the filter-impermeable gas pipe. The present invention provides a component separation and recovery apparatus for an HFC mixed refrigerant, comprising: an R125 recovery pipe connected to the R125 recovery container and having an R125 recovery valve in its path; an R410A circulation pipe branching from the filter-impermeable gas pipe and connected between the R410A supply valve and the expansion valve of the R410A supply pipe, and having a first R410A circulation valve, an R410A buffer tank, and a second R410 circulation valve in its path; a permeable side pressure switch provided between the filter unit and the R32 buffer tank of the R32 recovery pipe; and an impermeable side pressure switch provided between the first R410A circulation valve and the R410A buffer tank of the R410A circulation pipe. The filter unit has a double-tube structure consisting of an outer cylinder and a filter tube housed within the outer cylinder, the filter tube being made of a molecular sieve membrane, the R410A supply pipe being connected to one end of the filter unit and communicating with the inside of the filter tube, the filter-impermeable gas pipe being connected to the other end of the filter unit and communicating with the inside of the filter tube, and the R32 recovery pipe may be connected to the outer surface of the outer cylinder and communicating with the inside of the outer cylinder. The R410 supply pipe may have a pressure reducing valve between the evaporator and the R410A compressor.

[0011] Furthermore, the present invention comprises an R410A supply step, (1) starting the R410A compressor with the R410A supply valve and the first R410A circulation valve open and the R125 recovery valve and the second R410 circulation valve closed to supply R410A from the R410A filling container and store R410A in the R410A buffer tank, and (2) closing the R410A supply valve and opening the second R410 circulation valve and the R410A buffer tank (3) The R410A circulation and R32 recovery process involves sending the R410A stored in the buffer tank to the filter unit, storing the R32 separated by passing it through the filter unit in the R32 recovery container, and storing the R410A containing R125 that does not pass through the filter unit in the R410A buffer tank and circulating it. The present invention provides a method for separating and recovering components of an HFC mixed refrigerant using an HFC mixed refrigerant component separation and recovery apparatus, comprising: an R125 recovery step, in which R410A containing R125, after separating R32 stored in a buffer tank, is stored in the R125 recovery container via the R125 recovery pipe 125; in step (1), when the non-permeable side pressure switch reaches a predetermined pressure or higher, the process moves to step (2); in step (2), when the non-permeable side pressure switch falls below a predetermined pressure, the process returns to step (1); in step (2), the R32 compressor is started to send the R32 stored in the R32 buffer tank to the R32 recovery container, the permeable side pressure switch is started when it falls below a predetermined pressure, the R32 compressor is stopped, and when the cumulative time of steps (1) and (2) reaches a certain level or higher, the process moves to step (3). [Effects of the Invention]

[0012] The present invention, by means of solving the above-mentioned problems, can achieve at least one of the following effects. <1> Since the temperature of the R410A to be separated is not controlled, a temperature control device and a heat transfer medium for heating and cooling are not required. <2> By using a molecular sieve membrane and separating the materials through the molecular sieving effect, the azeotropic mixture R125 and R32 can be separated and recovered. <3>By providing a pressure reducing valve between the evaporator and the R410A compressor, the suction pressure of the R410A compressor can be maintained at an appropriate pressure.

Brief Description of the Drawings

[0013] [Figure 1] Overall explanatory drawing of the component separation and recovery device for the HFC mixed refrigerant of the present invention [Figure 2] Explanatory drawing of separation by the filter unit [Figure 3] Explanatory drawing (1) of the component separation and recovery method using the component separation and recovery device for the HFC mixed refrigerant of the present invention [Figure 4] Explanatory drawing (2) of the component separation and recovery method using the component separation and recovery device for the HFC mixed refrigerant of the present invention [Figure 5] Explanatory drawing (3) of the component separation and recovery method using the component separation and recovery device for the HFC mixed refrigerant of the present invention

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Examples

[0015] <1>Overview of the component separation and recovery device for the HFC mixed refrigerant (Fig. 1) The component separation and recovery device for the HFC mixed refrigerant of the present invention separates and recovers R125 and R32, which are components of R410A, a HFC mixed refrigerant. The component separation and recovery device for the HFC mixed refrigerant of the present invention separates by supplying R410A to the filter unit 1 having a molecular sieve membrane, utilizing the difference in the molecular diameters of R125 and R32. Also, by circulating the R410A to be separated within the device and passing it through the filter unit 1 multiple times, the certainty of the separation of R125 and R32 is enhanced.

[0016] <2>Overall configuration of the component separation and recovery device for the HFC mixed refrigerant (Fig. 1) The HFC mixed refrigerant component separation and recovery apparatus of the present invention comprises an R410A-filled container 2 filled with R410A to be separated, an R32 recovery container 3 and an R125 recovery container 4 for recovering R32 and R125 separated from R410A, respectively. The R410A-filled container 2, the R32 recovery container 3 and the R125 recovery container 4 are connected by piping made of charge hoses, stainless steel tubes, etc., as appropriate, as described below. An R410A supply pipe 21 is connected to the R410A-filled container 2, and the R410A supply pipe 21 is connected to one end of the filter unit 1 via an R410A supply valve SV1 that opens and closes the pipeline, an expansion valve 22, an evaporator 23, a pressure reducing valve 24, and an R410A compressor 5. The filter unit 1 has an R32 recovery pipe 31 connected to its outer surface, and the R32 recovery pipe 31 is connected to the R32 recovery container 3 via an R32 buffer tank 34 and an R32 compressor 6. A permeation-side pressure switch PS1 is provided between the filter unit 1 and the R32 buffer tank 34. A check valve 33 may also be provided between the filter unit 1 and the R32 buffer tank 34. A filter-impermeable gas pipe 11 is connected to the other end of the filter unit 1. The filter-impermeable gas pipe 11 branches into an R125 recovery pipe 41 and an R410A circulation pipe 71. The R125 recovery pipe 41 is connected to the R125 recovery container 4 via an R125 recovery valve SV2 that opens and closes the pipeline. The R410A circulation pipe 71 is connected between the R410A supply valve SV1 and the expansion valve 22 of the R410A supply pipe 21 via a first R410A circulation valve SV3 that opens and closes the pipeline, an R410A buffer tank 7, and a second R410A circulation valve SV4 that opens and closes the pipeline. A filter-impermeable pressure switch PS2 is installed in front of the R410A buffer tank 7 (between the first R410A circulation valve SV3 and the R410A buffer tank 7) on the R410A circulation pipe 71. The R410A supply valve SV1, the R125 recovery valve SV2, the first R410A circulation valve SV3, and the second R410 circulation valve SV4 shall be electrically operated valves, solenoid valves, or other devices that open and close automatically in response to signals.

[0017] <3> Separation by filter unit 1 (Figure 2) The R410A to be separated is stored in liquid form in the R410A-filled container 2 and supplied to the filter unit 1 in gaseous form after passing through the expansion valve 22 and evaporator 23. Since temperature control is not performed and the R410A is converted to gas by the expansion valve 22 and evaporator 23 using the heat of the surrounding air, a temperature control device and a heat transfer medium for heating and cooling are not required. The filter unit 1 has a double-tube structure consisting of an outer cylinder 12 and a filter tube 13 that is housed within the outer cylinder 12. The filter tube 13 is composed of a molecular sieve membrane made of organic polymer. R410A is an azeotropic mixture of R125 and R32, making separation by distillation difficult. In this invention, the difference in molecular diameters between R125 and R32 is utilized, and separation is performed by molecular sieving using a molecular sieve membrane with pores of a size that allows only R32 to pass through. The theoretical molecular diameter of R32 at 25°C and 0.6 MPa is 0.362 nm, and the theoretical molecular diameter of R125 is 0.446 nm. The R410A supply pipe 21 connected to one end of the filter unit 1 and the filter-impermeable gas pipe 11 connected to the other end are both connected to the inside of the filter pipe 13. The R32 recovery pipe 31 is connected to the outer surface of the outer cylinder 12 and is connected to the inside of the outer cylinder 12, which is outside the filter pipe 13. When R410A is supplied from the R410A supply pipe 21 to the filter pipe 13, which is the inner tube of the filter unit 1, only R32 permeates out of the filter pipe 13 and is sent to the R32 recovery pipe 31. R125, which does not permeate the filter pipe 13, passes through the inside of the filter pipe 13 and is sent to the filter-impermeable gas pipe 11.

[0018] <4> Component separation and recovery method using an HFC mixed refrigerant component separation and recovery device Next, a method for separating and recovering components using the HFC mixed refrigerant component separation and recovery apparatus of the present invention will be described.

[0019] <4.1> Process 1: R410A supply process (Figure 3) With the R410A supply valve SV1 and the first R410A circulation valve SV3 open, and the R125 recovery valve SV2 and the second R410 circulation valve SV4 closed, the R410A compressor 5 is started to supply R410A from the R410A filled container 2 into the device. The liquid R410A supplied from the R410A-filled container 2 passes through the expansion valve 22 and evaporator 23 to become a gas, which is then compressed by the R410A compressor 5 and supplied to the filter unit 1 at a predetermined pressure. A pressure reducing valve 24 is provided between the evaporator 23 and the R410A compressor 5 to maintain the suction pressure of the R410A compressor 5 at an appropriate level. A portion of the R32 in the R410A supplied to the filter unit 1 passes through the filter tube 13 and is sent from the R32 recovery tube 31 to the R32 buffer tank 34. The R410A, including the R125 that does not pass through the filter tube 13 and the R32 that does not pass through the filter tube 13, is stored as a liquid in the R410A buffer tank 7 via the filter-impermeable gas tube 11 and the R410A circulation tube 71. As the amount of R410A stored in the R410A buffer tank 7 increases, the pressure in the R410A circulation pipe 71 in front of the R410A buffer tank 7 rises. When the amount of R410A in the R410A buffer tank 7 reaches a predetermined level, the pressure in the R410A circulation pipe 71 in front of the R410A buffer tank 7 exceeds a predetermined level, and the non-permeable side pressure switch PS2 in front of the R410A buffer tank 7 is activated. The process then proceeds to the next R410A separation step.

[0020] <4.2> Process 2: R410A circulation and R32 recovery process (Figure 4) The R410A supply valve SV1 is closed to stop the supply from the R410A filled container 2, and the second R410A circulation valve SV4 is opened to circulate the R410A in the R410A buffer tank 7 within the device. The liquid R410A stored in the R410A buffer tank 7 passes through the expansion valve 22 and evaporator 23 to become a gas, which is then compressed by the R410A compressor 5 and supplied to the filter unit 1 at a predetermined pressure. Then, a portion of the R32 in the R410A supplied to the filter unit 1 passes through the filter tube 13 and is sent from the R32 recovery tube 31 to the R32 buffer tank 34. The R410A, including the R125 that does not pass through the filter tube 13 and the R32 that does not pass through the filter tube 13, is stored as a liquid in the R410A buffer tank 7 via the filter-impermeable gas tube 11 and the R410A circulation tube 71, and is circulated back into the device. By circulating the R410A within the device and passing it through the filter unit 1 multiple times, the reliability of separating R125 and R32 is increased. Furthermore, the R32 compressor 6 is started to send the R32 in the R32 buffer tank 34 to the R32 recovery container 3 for storage, thereby recovering R32 from the device. When the R32 compressor 6 is started, the R32 recovery pipe 31 connected to the suction side of the R32 compressor 6 and the outer circumference side of the filter unit 1 (the side after permeation of the filter pipe 13) are depressurized, so the amount of R32 that permeates through the filter pipe 13 increases, and the certainty of separation between R125 and R32 is also increased. When the amount of R32 in the R32 buffer tank 34 and the amount of R32 that permeates through the filter pipe 13 decreases, the pressure at the permeation side pressure switch PS1 between the filter unit 1 and the R32 buffer tank 34 decreases. When the pressure falls below a predetermined level, the permeation side pressure switch PS1 is activated and the R32 compressor 6 is stopped. As R32 is separated and recovered, and the amount of R410A in the device decreases, the pressure in the R410A circulation pipe 71 in front of the R410A buffer tank 7 decreases. Therefore, when the pressure in the R410A circulation pipe 71 in front of the R410A buffer tank 7 falls below a predetermined level, the non-permeable side pressure switch PS2 is activated, and the process returns to step 1 in <4.1>.

[0021] <4.3> Process 3: R125 Recovery Process (Figure 5) After separating R32 from R410A through steps 1 and 2, only R125 will circulate within the device. Therefore, once the cumulative time for processes 1 and 2 exceeds a certain level, the process moves on to the R125 recovery process. In this process, the first R410A circulation valve SV3 is closed and the R125 recovery valve SV2 is opened. The R410A buffer tank 7 and R125 in the device are sent by the R410A compressor 5 through the filter unit 1 and the filter-impermeable gas pipe 11, the R410A circulation pipe 71, and the R125 recovery pipe 41 to the R125 recovery container 4 for storage, thereby recovering R125 from the device. Then, after a certain period of time has elapsed, the process returns to step 1, and steps 1 to 3 are repeated to separate and recover all of the R410A in the R410A-filled container 2.

[0022] <5> Other applications include HFC mixed refrigerants. In this embodiment, R410A, which consists of R125 and R32, was described. However, R410A of lower quality may contain other fluorocarbons. Since the molecular diameter of R32 is small among fluorocarbons, other fluorocarbons do not permeate the filter tube 13. Therefore, by using this apparatus, high-purity R32 can be recovered. Furthermore, even with other combinations of HFC mixed refrigerants, separation can be performed using this device by selecting the pore size of the organo-type separation membrane of the filter tube 13 according to the difference in molecular size. [Explanation of symbols]

[0023] 1 Filter unit, 11 Filter-impermeable gas pipe, 12 Outer cylinder, 13 Filter pipe, 2 R410A filled container, 21 R410A supply pipe, 22 Expansion valve, 23 Evaporator, 24 Pressure reducing valve, 3 R32 recovery container, 31 R32 recovery pipe, 33 Check valve, 34 R32 buffer tank, 4 R125 recovery container, 41 R125 recovery pipe, 5 R410A compressor, 6 R32 compressor, 7 R410A buffer tank, 71 R410A circulation pipe PS1 is a permeable pressure switch, PS2 is a non-permeable pressure switch. SV1 R410A supply valve, SV2 R125 recovery valve, SV3 First R410A circulation valve, SV4 Second R410A circulation valve

Claims

1. An R410A-filled container filled with R410A, An R32 recovery container for recovering R32 separated from R410A, An R125 recovery container for recovering R125 separated from R410A, The R410A supply pipe is connected to the R410A filled container and the filter unit, and has an R410A supply valve, expansion valve, evaporator, and R410A compressor in its path. The filter unit and the R32 recovery container are connected, and the R32 recovery pipe has an R32 buffer tank and an R32 compressor in its path, A filter-impermeable gas pipe connected to the aforementioned filter unit, An R125 recovery pipe, which branches off from the filter-impermeable gas pipe and connects to the R125 recovery container, and has an R125 recovery valve in its path, A R410A circulation pipe is branched from the filter-impermeable gas pipe and connected between the R410A supply valve and the expansion valve of the R410A supply pipe, and has a first R410A circulation valve, an R410A buffer tank, and a second R410A circulation valve in its path. A permeate-side pressure switch is provided between the filter unit and the R32 buffer tank of the R32 recovery pipe, The R410A circulation pipe has a non-permeable side pressure switch installed between the first R410A circulation valve and the R410A buffer tank, A device for separating and recovering components of HFC mixed refrigerants.

2. The filter unit has a double-tube structure consisting of an outer cylinder and a filter tube housed within the outer cylinder. The filter tube is made of a molecular sieve membrane, The R410A supply pipe is connected to one end of the filter unit, communicating with the inside of the filter tube. The filter-impermeable gas pipe is connected to the other end of the filter unit, communicating with the inside of the filter pipe. The R32 recovery pipe is characterized by being connected to the outer surface of the outer cylinder in communication with the inside of the outer cylinder. The HFC mixed refrigerant component separation and recovery apparatus according to claim 1.

3. The R410 supply pipe is characterized by having a pressure reducing valve between the evaporator and the R410A compressor. The HFC mixed refrigerant component separation and recovery apparatus according to claim 1.

4. (1) An R410A supply step in which the R410A supply valve and the first R410A circulation valve are opened, the R125 recovery valve and the second R410 circulation valve are closed, the R410A compressor is started to supply R410A from the R410A filling container, and the R410A is stored in the R410A buffer tank, (2) The R410A supply valve is closed, the second R410 circulation valve is opened, the R410A stored in the R410A buffer tank is sent to the filter unit, the R32 separated by passing through the filter unit is stored in the R32 recovery container, and the R410A containing R125 that does not pass through the filter unit is stored in the R410A buffer tank and circulated, an R410A circulation and R32 recovery process, (3) The process consists of an R125 recovery step, in which the first R410A circulation valve is closed, the R125 recovery valve is opened, and the R32 stored in the R410A buffer tank is separated, and the R410A containing R125 is stored in the R125 recovery container via the R125 recovery pipe 125. In step (1), when the non-permeable side pressure switch reaches a predetermined pressure or higher, it activates and the process moves to step (2). In step (2), when the non-permeable side pressure switch falls below a predetermined pressure, the process returns to step (1). The (2) step involves starting the R32 compressor to send the R32 stored in the R32 buffer tank to the R32 recovery container, and when the permeate side pressure switch falls below a predetermined pressure, it activates to stop the R32 compressor. When the cumulative time of steps (1) and (2) exceeds a certain amount, the process moves on to step (3). A method for separating and recovering components of an HFC mixed refrigerant using an HFC mixed refrigerant component separation and recovery apparatus according to any one of claims 1 to 3.

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