Method for producing chlorofluorocarbon refrigerant, method for storing chlorofluorocarbon refrigerant, method for producing heat pump device, and carbon dioxide storage system

Abstract

This method for producing a chlorofluorocarbon refrigerant comprises: a step in which an adsorbent is used to collect carbon dioxide; and a step in which the collected carbon dioxide is used as a raw material to synthesize the chlorofluorocarbon refrigerant.

Description

Method for producing fluorocarbon refrigerant, method for storing fluorocarbon refrigerant, method for producing heat pump device, and carbon dioxide storage system

[0001] The present disclosure relates to a method for producing a fluorocarbon refrigerant, a method for storing a fluorocarbon refrigerant, a method for producing a heat pump device, and a carbon dioxide storage system.

[0002] Patent Document 1 discloses a DAC (Direct Air Capture) technology that captures carbon dioxide from factory exhaust or the air around a factory.

[0003] International Publication No. 2021 / 230045

[0004] For example, from the perspective of preventing global warming, carbon dioxide fixation technology is also being researched to prevent the carbon dioxide captured by the above technology from being released into the atmosphere. However, if the captured carbon dioxide is prevented from being released into the atmosphere by storing it in underground facilities or tanks, it may require a huge amount of labor and energy to manage these.

[0005] In view of the above circumstances, the present disclosure aims to provide a method for producing a fluorocarbon refrigerant, a method for storing a fluorocarbon refrigerant, a method for producing a heat pump device, and a carbon dioxide storage system that can reduce the effort and energy required to store and manage recovered carbon dioxide.

[0006] One aspect of the method for producing a fluorocarbon refrigerant according to the present disclosure includes a step of recovering carbon dioxide using an adsorbent, and a step of synthesizing a fluorocarbon refrigerant using the recovered carbon dioxide as a raw material.

[0007] According to one aspect of the present disclosure, carbon dioxide can be captured from a gas to be treated, such as the atmosphere, indoor air, or factory exhaust, using an adsorbent, and the captured carbon dioxide can be used as a raw material to synthesize a fluorocarbon refrigerant. The fluorocarbon refrigerant is chemically stable, and by using it as a heat medium in a heat pump device, for example, the synthesized fluorocarbon refrigerant can be stably stored in the heat pump device from the time the heat pump device is manufactured until it is disposed of. In other words, there is no need to prepare separate underground facilities or tanks for storing the captured carbon dioxide, which reduces the labor and energy required to store and manage the captured carbon dioxide.

[0008] It is a schematic diagram of a carbon dioxide storage system according to an embodiment. It is a schematic diagram of a carbon dioxide recovery device included in the carbon dioxide storage system according to an embodiment. It is a schematic diagram of a carbon recycling fluorocarbon refrigerant synthesis device included in the carbon dioxide storage system according to an embodiment. It is a schematic diagram of a heat pump device included in the carbon dioxide storage system according to an embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments, and can be arbitrarily modified within the scope of the appended claims.

[0010] Fig. 1 is a schematic diagram of a carbon dioxide storage system 1 according to the present embodiment. As shown in Fig. 1, the carbon dioxide storage system 1 converts carbon dioxide (CO ２ The carbon dioxide storage system 1 includes a carbon dioxide recovery unit 50 that recovers carbon dioxide from the gas to be treated, a carbon recycling fluorocarbon refrigerant synthesis unit 60 that synthesizes a fluorocarbon refrigerant from the recovered carbon dioxide, and a heat pump unit 70 that uses the synthesized fluorocarbon refrigerant as a heat medium.

[0011] Fig. 2 is a schematic diagram of a carbon dioxide capture device 50 according to the present embodiment. As shown in Fig. 2, the carbon dioxide capture device 50 includes a first supply path 2, a carbon dioxide adsorption unit 3, a first outlet path 4, a regenerating fluid supply unit 5, a second supply path 6, a heater 7, a pressure reducer 8, a second outlet path 9, a carbon dioxide separator 10, a compressor 11, and a cooler 12.

[0012] The first supply path 2 is connected to an adsorption region 31 (described later) of the carbon dioxide adsorption unit 3. The first supply path 2 guides a gas to be treated, such as atmospheric air, room air, or factory exhaust, to the adsorption region 31 of the carbon dioxide adsorption unit 3. The first supply path 2 is provided with a blower 21 for sending the gas to be treated to the carbon dioxide adsorption unit 3. Note that if the gas to be treated introduced into the first supply path 2 can flow to the carbon dioxide adsorption unit 3 without using the blower 21, the blower 21 need not be provided. If the gas to be treated is factory exhaust or the like, the first supply path 2 may be provided with an exhaust gas treatment device for removing nitrogen oxides, soot, and the like from the gas to be treated in advance.

[0013] The carbon dioxide adsorption unit 3 includes a first region 3A and a second region 3B. The first region 3A and the second region 3B each include an adsorbent capable of adsorbing carbon dioxide and a container for accommodating the adsorbent. The container for the first region 3A and the container for the second region 3B are configured to be interchangeable. The carbon dioxide adsorption unit 3 also includes an adsorption region 31 that adsorbs carbon dioxide contained in the gas to be treated, and a regeneration region 32 that regenerates the adsorbent to which carbon dioxide has been adsorbed. In this embodiment, "regeneration" refers to desorbing carbon dioxide from the adsorbent to which carbon dioxide has been adsorbed, thereby returning the adsorbent to a state capable of adsorbing carbon dioxide again. In the example shown in FIG. 2 , the first region 3A is the adsorption region 31, and the second region 3B is the regeneration region 32.

[0014] Examples of adsorbents include amines, silica gel, zeolites, activated carbon, diatomaceous earth, and alumina. By adsorbing carbon dioxide contained in the gas to be treated onto the adsorbent, the carbon dioxide can be separated from other components of the gas to be treated. The adsorbent may be in the form of granules or powder. Examples of granules include beads (spherical) and pellets (cylindrical). When a powder adsorbent is used, the adsorbent may be supported on the surface of a substrate. The substrate may have a honeycomb shape.

[0015] In the adsorption region 31, at least a portion of the carbon dioxide contained in the gas to be treated is adsorbed by the adsorbent and removed, so that gas having a lower concentration of carbon dioxide than the gas to be treated is obtained.

[0016] The regeneration region 32 regenerates the adsorbent that has adsorbed carbon dioxide in the adsorption region 31 using a regenerating fluid F1 supplied by the regenerating fluid supply unit 5. The regeneration region 32 has the function of desorbing carbon dioxide from the adsorbent. The regeneration region 32 is equipped with a heating device, such as a heater, that heats the adsorbent. The heating device desorbs carbon dioxide from the adsorbent by heating the adsorbent in the presence of the regenerating fluid F1. The adsorbent is regenerated by the desorption of carbon dioxide. The regenerating fluid F1 containing the carbon dioxide desorbed from the adsorbent is discharged from the regeneration region 32 as a regeneration discharge fluid F2.

[0017] The regeneration zone 32 may include a pressure reducing device, such as a vacuum pump, that places the adsorbent under reduced pressure to promote desorption of carbon dioxide from the adsorbent.

[0018] The first outlet path 4 is connected to the adsorption region 31. Gas with a reduced carbon dioxide concentration, obtained by passing the gas to be treated through the adsorption region 31, is introduced into the first outlet path 4. The first outlet path 4 releases the gas with a reduced carbon dioxide concentration due to the adsorption region 31 into the atmosphere, a living space, or the like. If the gas to be treated is factory exhaust, for example, an exhaust gas treatment device may be provided in the first outlet path 4.

[0019] The regenerating fluid supply unit 5 is a supply source of the regenerating fluid F1, and supplies the regenerating fluid F1 toward the regenerating region 32 of the carbon dioxide adsorption unit 3. The regenerating fluid supply unit 5 may include a tank for storing the regenerating fluid F1, a discharge pump for sending the regenerating fluid F1 toward the regenerating region 32, and the like. The regenerating fluid F1 may be, for example, nitrogen (N ２ ), hydrogen (H ２ ), methane (CH ４ The regenerating fluid F1 in this embodiment is a gas, but may also be a liquid.

[0020] The second supply path 6 is connected to the regenerating fluid supply unit 5 and the regenerating region 32 of the carbon dioxide adsorption unit 3. The second supply path 6 guides the regenerating fluid F1 supplied from the regenerating fluid supply unit 5 to the regenerating region 32.

[0021] The heater 7 and the pressure reducer 8 are provided in the second supply path 6. The pressure reducer 8 is provided downstream of the heater 7, i.e., between the heater 7 and the regeneration zone 32. The heater 7 is, for example, a heat exchanger or a heater, and can heat the regeneration fluid F1 to a temperature suitable for desorption of carbon dioxide from the adsorbent in the regeneration zone 32. The heater 7 can, for example, heat the regeneration fluid F1 so that the temperature of the regeneration fluid F1 in the regeneration zone 32 is 90°C to 120°C. The pressure reducer 8 is, for example, a pressure reducing valve, and reduces the pressure of the regeneration fluid F1 to a pressure suitable for desorption of carbon dioxide from the adsorbent in the regeneration zone 32. Note that the heater 7 and the pressure reducer 8 are not essential elements in this embodiment, and one or both of them may not be provided in the second supply path 6.

[0022] The second outlet path 9 is connected to the regeneration region 32 of the carbon dioxide adsorption unit 3 and the carbon dioxide separator 10. The second outlet path 9 guides the regeneration discharge fluid F2 discharged from the regeneration region 32 to the carbon dioxide separator 10.

[0023] The carbon dioxide separator 10 separates at least a portion of the carbon dioxide contained in the regeneration discharge fluid F2 using a separation method such as liquefaction separation, membrane separation, adsorption separation, etc. The carbon dioxide separator 10 may employ one of these separation methods or a combination of two or more of them.

[0024] The carbon dioxide separator 10 using liquefaction separation liquefies, for example, a specific component and separates it from other components (gases) in the regeneration discharge fluid F2. Specifically, for example, carbon dioxide is liquefied under high-pressure and low-temperature conditions and separated from other components (gases).

[0025] The carbon dioxide separator 10 using membrane separation separates a specific component from other components, for example, by using a separation membrane that allows small molecular components to permeate. Specifically, for example, a separation membrane that selectively allows carbon dioxide to permeate is used. This separation membrane separates carbon dioxide from a mixed fluid (i.e., regeneration discharge fluid F2) containing carbon dioxide and other components (nitrogen, hydrogen, methane, etc.). Examples of separation membranes include organic membranes (such as dendrimer membranes) and inorganic membranes (such as zeolite membranes, silica membranes, and carbon membranes).

[0026] The carbon dioxide separator 10 using adsorption separation separates specific components by, for example, adsorbing them onto an adsorbent. Examples of adsorbents include amines, silica gel, zeolites, activated carbon, diatomaceous earth, and alumina. Specifically, for example, carbon dioxide can be separated from other components in the regeneration discharge fluid F2 by adsorbing it onto the adsorbent.

[0027] The carbon dioxide separated from the regeneration discharge fluid F2 in the carbon dioxide separator 10 is supplied to the carbon recycled fluorocarbon refrigerant synthesis device 60. The regeneration discharge fluid F2, whose carbon dioxide concentration has been reduced by the separation of the carbon dioxide, is discharged as discharge fluid F3 from the carbon dioxide separator 10. The discharge fluid F3 may be supplied to the regeneration fluid supply unit 5 and reused as the regeneration fluid F1.

[0028] The compressor 11 and the cooler 12 are provided in the second outlet path 9. The cooler 12 is provided downstream of the compressor 11, i.e., between the compressor 11 and the carbon dioxide separator 10. The compressor 11 can increase the pressure of the regeneration discharge fluid F2 to a pressure suitable for separating carbon dioxide from the regeneration discharge fluid F2 in the carbon dioxide separator 10. The cooler 12 is, for example, a heat exchanger, and can lower the temperature of the regeneration discharge fluid F2, which has been increased to a high temperature by pressurization by the compressor 11, to a temperature suitable for separating carbon dioxide from the regeneration discharge fluid F2 in the carbon dioxide separator 10. Note that the compressor 11 and the cooler 12 are not essential elements in this embodiment, and one or both of them may not be provided in the second outlet path 9.

[0029] At least one of the devices included in the carbon dioxide capture device 50 may be driven by renewable energy such as sunlight, wind power, hydropower, geothermal power, solar heat, atmospheric heat, or other heat present in nature. In other words, the carbon dioxide capture device 50 may be configured to capture carbon dioxide using renewable energy.

[0030] 3 is a schematic diagram of a carbon recycled fluorocarbon refrigerant synthesis unit 60 according to the present embodiment. As shown in FIG. 3, the carbon recycled fluorocarbon refrigerant synthesis unit 60 uses carbon dioxide (CO ２ ) and hydrogen (H ２ a hydrocarbon synthesis unit 15 for synthesizing hydrocarbons from the hydrocarbons and chlorine (Cl ２ ) and dichloromethane (CH ２ Cl ２ a dichloromethane synthesis unit 16 that synthesizes dichloromethane (CH 2 ), which is a fluorocarbon refrigerant, by reacting the dichloromethane with hydrogen fluoride (HF); ２ F ２ and a fluorocarbon refrigerant synthesis unit 17 for synthesizing a fluorocarbon refrigerant (refrigerant number: R32).

[0031] The hydrocarbon synthesis unit 15 includes a catalyst that promotes a synthesis reaction from carbon dioxide and hydrogen to hydrocarbons, and a reaction chamber (reactor) that houses the catalyst and into which the carbon dioxide and hydrogen recovered by the carbon dioxide recovery unit 50 are introduced. The hydrocarbons synthesized in the hydrocarbon synthesis unit 15 include, for example, methane (CH ４ ) The catalyst in the hydrocarbon synthesis section 15 may be, for example, a solid catalyst using an inorganic material or a biocatalyst using a bacterium. In order to maintain such a catalyst at a temperature suitable for hydrocarbon synthesis, the hydrocarbon synthesis section 15 may be provided with a heating device such as a heater or a cooling device using a heat exchanger. The hydrocarbons synthesized in the hydrocarbon synthesis section 15 are supplied to the dichloromethane synthesis section 16.

[0032] The hydrogen supplied to the hydrocarbon synthesis section 15 may be produced by any method, but may be produced by electrolysis of water, and renewable energy may be used for this electrolysis.

[0033] The dichloromethane synthesis unit 16 synthesizes the hydrocarbon (methane) synthesized in the hydrocarbon synthesis unit 15 and chlorine (Cl ２ The dichloromethane synthesis unit 16 includes a reaction chamber (reactor) into which hydrocarbon (methane) is introduced, and a heating device such as a heater for heating the inside of the reaction chamber. The chlorine supplied to the dichloromethane synthesis unit 16 may be produced by any method. The heating device of the dichloromethane synthesis unit 16 raises the temperature inside the reaction chamber to a temperature suitable for causing a radical reaction between hydrocarbon (methane) and chlorine, for example, to 400°C to 500°C. Dichloromethane (CH ２ Cl ２ The synthesized dichloromethane is supplied to the fluorocarbon refrigerant synthesis section 17. Renewable energy may be used to operate the heating device.

[0034] In addition to or instead of the heating device of the dichloromethane synthesis section 16, a photocatalyst that promotes a radical reaction between hydrocarbon and chlorine by irradiation with light may be provided in the reaction chamber.

[0035] The fluorocarbon refrigerant synthesis unit 17 converts dichloromethane and hydrogen fluoride (HF) into difluoromethane (CH ２ F２ The fluorination catalyst includes a fluorination catalyst that promotes a synthesis reaction to produce dichloromethane (dichloromethane), and a reaction chamber (reactor) that houses the fluorination catalyst and receives the dichloromethane synthesized in the dichloromethane synthesis unit 16 and hydrogen fluoride. The hydrogen fluoride supplied to the fluorocarbon refrigerant synthesis unit 17 may be produced by any method. Examples of the fluorination catalyst include a catalyst that has a catalytic component containing chromium oxide as a main component and optionally further containing at least one element selected from the group consisting of In, Zn, Ni, Co, Mg, and Al, and a carrier that supports the catalytic component, and at least a portion of the catalytic component is fluorinated with hydrogen fluoride. The carrier may be, for example, activated alumina having fine pores.

[0036] In order to raise the temperature of the fluorination catalyst in fluorocarbon refrigerant synthesis section 17 to a temperature suitable for synthesizing difluoromethane, fluorocarbon refrigerant synthesis section 17 may be provided with a heating device such as a heater or a cooling device using a heat exchanger, etc. Difluoromethane synthesized in fluorocarbon refrigerant synthesis section 17 is supplied to heat pump unit 70 directly or via a cylinder, etc.

[0037] The fluorocarbon refrigerant synthesized in the carbon recycled fluorocarbon refrigerant synthesis unit 60 is a hydrofluorocarbon (HFC) made from the carbon dioxide recovered in the carbon dioxide recovery unit 50, and does not contain chlorine.

[0038] The carbon recycled fluorocarbon refrigerant synthesis unit 60 may further include a mixed refrigerant production unit (not shown) that produces a mixed refrigerant containing, as one of its components, the difluoromethane synthesized in the fluorocarbon refrigerant synthesis unit 17. Such a mixed refrigerant production unit includes a mixer, and the difluoromethane synthesized in the fluorocarbon refrigerant synthesis unit 17 and another refrigerant supplied from outside the carbon recycled fluorocarbon refrigerant synthesis unit 60 are supplied to the mixer and mixed together to produce a mixed refrigerant.

[0039] The other refrigerant supplied to the mixed refrigerant production section from outside the carbon recycled fluorocarbon refrigerant synthesis unit 60 may be not only a newly produced refrigerant but also a refrigerant recovered from an existing heat pump device, for example. Examples of the other refrigerant include fluorocarbon refrigerants and olefin-based refrigerants (hydrofluoroolefins, HFOs). Examples of the other fluorocarbon refrigerants supplied from outside the carbon recycled fluorocarbon refrigerant synthesis unit 60 include hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), and examples of these hydrochlorofluorocarbons include chlorodifluoromethane (CHClF ２ By supplying chlorodifluoromethane to the mixed refrigerant production section, a mixed refrigerant of the chlorodifluoromethane and the difluoromethane synthesized in the fluorocarbon refrigerant synthesis section 17 can be produced.

[0040] Examples of olefin-based refrigerants supplied to the mixed refrigerant production unit include HFO-1123, HFO-1224yd, HFO-1234yf, HFO-1234ze, R1233zd (HFO-1233zd), HFO-1226mzz(Z), HFO-1336mzz-Z, and HFO-1336mzz-E. By supplying an olefin-based refrigerant to the mixed refrigerant production unit, a mixed refrigerant of the olefin-based refrigerant and difluoromethane synthesized in fluorocarbon refrigerant synthesis unit 17 can be produced.

[0041] Fig. 4 is a schematic diagram of a heat pump unit 70 according to the present embodiment. As shown in Fig. 4, the heat pump unit 70 includes a gas-to-liquefaction heat pump 80 and a recovery port 86. The heat pump 80 includes a heater 81, an expander 82, a cooler 83, a compressor 84, and a circulation path 85. The circulation path 85 is filled with refrigerant F4 so as to be circulatable.

[0042] The heater 81 is a heat exchanger that exchanges heat between the refrigerant F4 and a fluid F5 flowing outside the heat pump device 70. That is, the heater 81 heats the fluid F5 by exchanging heat between the refrigerant F4, whose temperature has been increased by compression, and the fluid F5. The fluid F5 may be either a gas or a liquid. The expander 82 is, for example, an expansion valve, and reduces the pressure of the refrigerant F4, thereby lowering the temperature of the refrigerant F4.

[0043] The cooler 83 is a heat exchanger that exchanges heat between the refrigerant F4 and the fluid F6 flowing outside the heat pump device 70. That is, the cooler 83 cools the fluid F6 by exchanging heat between the refrigerant F4, whose temperature has been lowered by a pressure drop in the expander 82, and the fluid F6. The fluid F6 may be either a gas or a liquid. The compressor 84 compresses the refrigerant F4 to increase its pressure, thereby raising the temperature of the refrigerant F4.

[0044] Circulation path 85 is a circular path connecting heater 81, expander 82, cooler 83, and compressor 84 in this order. Circulation path 85 is filled with and stored as refrigerant F4, which is fluorocarbon refrigerant produced in carbon recycled fluorocarbon refrigerant synthesis device 60 (e.g., difluoromethane synthesized in fluorocarbon refrigerant synthesis section 17). Refrigerant F4 may be a mixed refrigerant. Refrigerant F4 circulates through heater 81, expander 82, cooler 83, and compressor 84 in this order.

[0045] The recovery port 86 is connected to the circulation path 85. The refrigerant F4 filled in the circulation path 85 can be recovered via the recovery port 86. For example, when the heat pump device 70 has reached the end of its service life and is to be discarded, the refrigerant F4 is recovered via the recovery port 86. The recovered refrigerant F4 may be supplied to the mixed refrigerant production section of the carbon recycled fluorocarbon refrigerant synthesis device 60, for example, to produce a new refrigerant (e.g., a mixed refrigerant). The recovery port 86 may also be used as a filling port for filling the circulation path 85 with the refrigerant F4.

[0046] The heat pump unit 70 may constitute, for example, an air conditioner. The air conditioner performs at least one of cooling and heating by utilizing heat absorption or heat release of the refrigerant F4. When heating the room, the indoor unit functions as a heater 81, and the outdoor unit functions as a cooler 83. When cooling the room, the indoor unit functions as a cooler 83, and the outdoor unit functions as the heater 81.

[0047] Heat pump unit 70 may constitute, for example, a refrigerator-freezer unit. The refrigerator-freezer unit cools the interior of the unit using a cooler 83 by utilizing the heat absorbed by refrigerant F4. Heat pump unit 70 may constitute, for example, a water heater or a washing machine with a drying function. The water heater heats water using a heater 81 by utilizing the heat released by refrigerant F4. The washing machine with a drying function heats air for drying clothes using a heater 81 by utilizing the heat released by refrigerant F4.

[0048] Next, a method for producing a fluorocarbon refrigerant, a method for storing a fluorocarbon refrigerant, and a method for producing a heat pump device in this embodiment will be described below. The operation of the carbon dioxide storage system 1 will also be described. Note that, as a method for producing a fluorocarbon refrigerant in this embodiment, a method using the carbon dioxide recovery device 50 and the carbon recycled fluorocarbon refrigerant synthesis device 60 described above will be described, but this is just one example, and fluorocarbon refrigerant may also be produced using other devices.

[0049] 2 , by operation of the blower 21, the gas to be treated is introduced via the first supply path 2 to the adsorption region 31 of the carbon dioxide adsorption unit 3. In the adsorption region 31, the carbon dioxide contained in the gas to be treated is adsorbed by the adsorbent, and at least a portion of the carbon dioxide is removed from the gas to be treated. The gas to be treated, with its carbon dioxide concentration now reduced, is released from the adsorption region 31 into the atmosphere or the living space via the first outlet path 4.

[0050] When the adsorption of carbon dioxide by the adsorbent in the adsorption region 31 becomes impossible or difficult due to the adsorption of carbon dioxide, the adsorbent is exchanged between the adsorption region 31 and the regeneration region 32. The container containing the adsorbent with adsorbed carbon dioxide in the adsorption region 31 is moved to the second region 3B of the carbon dioxide adsorption unit 3, and the container containing the regenerated adsorbent in the regeneration region 32 is moved to the first region 3A of the carbon dioxide adsorption unit 3. As a result, the regenerated adsorbent is placed in the adsorption region 31, and the adsorbent with adsorbed carbon dioxide is placed in the regeneration region 32. By placing the regenerated adsorbent in the adsorption region 31, the adsorption region 31 is once again able to adsorb carbon dioxide. By exchanging the adsorbent between the adsorption region 31 and the regeneration region 32 at regular intervals, an adsorbent capable of adsorbing carbon dioxide is maintained in the adsorption region 31.

[0051] The adsorbent may be replaced by removing the adsorbent in the adsorption region 31 from the container and moving it to the second region 3B, and by removing the adsorbent regenerated in the regeneration region 32 from the container and moving it to the first region 3A.

[0052] The adsorption region and the regeneration region can also be switched by changing the paths. In Fig. 2 , the first region 3A (left part in Fig. 2 ) of the carbon dioxide adsorption unit 3 is the adsorption region 31. The first supply path 2 and the first outlet path 4 are connected to the first region 3A. The second region 3B (right part in Fig. 2 ) is the regeneration region 32. The second supply path 6 and the second outlet path 9 are connected to the second region 3B.

[0053] By operating a valve provided in a branch path (not shown), the first supply path 2 and the first outlet path 4 are connected to the second region 3B, and the second supply path 6 and the second outlet path 9 are connected to the first region 3A. This operation causes the first region 3A to become a regeneration region, and the second region 3B to become an adsorption region. In this manner, the adsorption region and the regeneration region may be switched. After the second region 3B becomes an adsorption region and carbon dioxide adsorption is performed for a certain period of time, the first region 3A is returned to the adsorption region and the second region 3B is returned to the regeneration region by operating a valve, and this process is repeated thereafter.

[0054] The regenerating fluid supply unit 5 supplies the regenerating fluid F1, and the regenerating fluid F1 is introduced into the regeneration region 32 of the carbon dioxide adsorption unit 3 via the second supply path 6, the heater 7, and the pressure reducer 8. The heater 7 heats the regenerating fluid F1 to a temperature suitable for desorption of carbon dioxide from the adsorbent in the regeneration region 32. The heater 7 heats the regenerating fluid F1 so that the temperature of the regenerating fluid F1 in the regeneration region 32 is 90°C to 120°C, for example. The pressure reducer 8 reduces the pressure of the regenerating fluid F1 to a pressure suitable for desorption of carbon dioxide from the adsorbent in the regeneration region 32.

[0055] In the regeneration region 32, carbon dioxide is desorbed from the adsorbent in the presence of regeneration fluid F1. The adsorbent is regenerated by the desorption of carbon dioxide. That is, the adsorbent that adsorbed carbon dioxide in the adsorption region 31 is regenerated in the regeneration region 32. The carbon dioxide desorbed from the adsorbent is contained in the regeneration fluid F1, and the regeneration fluid F1 containing carbon dioxide is discharged from the regeneration region 32 via the second outlet path 9 as a regeneration discharge fluid F2.

[0056] The regeneration discharge fluid F2 discharged from the regeneration region 32 is introduced into the carbon dioxide separator 10 via the second outlet path 9, through the compressor 11 and the cooler 12. The compressor 11 increases the pressure of the regeneration discharge fluid F2 to a pressure suitable for separating carbon dioxide from the regeneration discharge fluid F2 in the carbon dioxide separator 10. The cooler 12 reduces the temperature of the regeneration discharge fluid F2, which has been increased to a high temperature by pressurization by the compressor 11, to a temperature suitable for separating carbon dioxide from the regeneration discharge fluid F2 in the carbon dioxide separator 10.

[0057] The carbon dioxide separator 10 separates and recovers at least a portion of the carbon dioxide contained in the regeneration discharge fluid F2 using a separation method such as liquefaction separation, membrane separation, or adsorption separation. The recovered carbon dioxide is supplied to the hydrocarbon synthesis section 15 of the carbon recycling fluorocarbon refrigerant synthesis unit 60. That is, the recovery of carbon dioxide from the gas to be treated is carried out in the carbon dioxide separator 10 of the carbon dioxide recovery unit 50. The regeneration discharge fluid F2, whose carbon dioxide concentration has been reduced by the separation of the carbon dioxide, is discharged from the carbon dioxide separator 10 as discharge fluid F3.

[0058] As shown in Figure 3, carbon dioxide captured in the carbon dioxide capture unit 50 is supplied to the hydrocarbon synthesis unit 15 of the carbon recycled fluorocarbon refrigerant synthesis unit 60. In the hydrocarbon synthesis unit 15, hydrocarbons (methane) are synthesized from the carbon dioxide captured in the carbon dioxide capture unit 50 and hydrogen. The synthesized hydrocarbons are supplied to the dichloromethane synthesis unit 16.

[0059] In the dichloromethane synthesis section 16, dichloromethane is synthesized by a radical reaction between the hydrocarbons synthesized in the hydrocarbon synthesis section 15 and chlorine. The synthesized dichloromethane is supplied to the fluorocarbon refrigerant synthesis section 17.

[0060] In the fluorocarbon refrigerant synthesis unit 17, the dichloromethane synthesized in the dichloromethane synthesis unit 16 is reacted with hydrogen fluoride to synthesize difluoromethane, a fluorocarbon refrigerant. In other words, the fluorocarbon refrigerant is synthesized using carbon dioxide recovered from the gas to be treated, completing the method for producing a fluorocarbon refrigerant in this embodiment. The fluorocarbon refrigerant synthesized in the carbon recycling fluorocarbon refrigerant synthesis unit 60 is supplied to the heat pump unit 70 directly or via a cylinder or the like.

[0061] As shown in FIG. 4 , the fluorocarbon refrigerant synthesized in the carbon recycled fluorocarbon refrigerant synthesis device 60 is filled as refrigerant F4 into the circulation path 85 of the heat pump device 70. As a result, the fluorocarbon refrigerant synthesized using carbon dioxide recovered from the gas to be treated as a raw material is filled and stored in the heat pump device 70. This completes the method for storing fluorocarbon refrigerant in this embodiment. In addition, in the manufacture of the heat pump device 70, the fluorocarbon refrigerant synthesized using carbon dioxide recovered from the gas to be treated as a raw material is filled into the heat pump device 70 that is not yet filled with refrigerant, thereby manufacturing the heat pump device 70. This completes the method for manufacturing the heat pump device in this embodiment. Furthermore, by filling the heat pump device 70 with the fluorocarbon refrigerant, it becomes possible to start using the heat pump device 70.

[0062] When the heat pump unit 70 reaches the end of its service life and is to be disposed of, the refrigerant F4 that has been filled in the circulation path 85 is recovered. The refrigerant F4 is recovered from the circulation path 85 via a recovery port 86. As shown in FIG. 1 , the refrigerant F4 recovered from the circulation path 85 of the heat pump unit 70 may be supplied to the mixed refrigerant production section of the carbon recycled fluorocarbon refrigerant synthesis unit 60 in order to produce a new refrigerant (or a mixed refrigerant).

[0063] The method for producing a fluorocarbon refrigerant in this embodiment includes a step of recovering carbon dioxide using an adsorbent and a step of synthesizing a fluorocarbon refrigerant using the recovered carbon dioxide as a raw material. Therefore, using the adsorbent, carbon dioxide can be recovered from the gas to be treated, such as the atmosphere, indoor air, or factory exhaust, and the recovered carbon dioxide can be used as a raw material to synthesize a fluorocarbon refrigerant. Fluorocarbon refrigerants are chemically stable, and when used as a heat medium in a heat pump device, for example, the synthesized fluorocarbon refrigerant can be stably stored within the heat pump device for a period from the manufacture to the disposal of the heat pump device (e.g., 10 to 20 years). In other words, there is no need to prepare separate underground facilities or tanks to store the recovered carbon dioxide, which reduces the labor and energy required to store and manage the recovered carbon dioxide.

[0064] In the method for producing a fluorocarbon refrigerant according to this embodiment, the carbon dioxide recovery step recovers the carbon dioxide using renewable energy. Using fossil fuels or the like to recover carbon dioxide from the gas to be treated generates greenhouse gases such as carbon dioxide during the recovery process, which is undesirable from the perspective of preventing global warming, for example. By using renewable energy to recover carbon dioxide, it is possible to suppress the generation of greenhouse gases during the recovery process.

[0065] In the method for producing a fluorocarbon refrigerant in this embodiment, the step of synthesizing the fluorocarbon refrigerant involves synthesizing a hydrocarbon from the recovered carbon dioxide and hydrogen, synthesizing dichloromethane by a radical reaction between the hydrocarbon and chlorine, and synthesizing difluoromethane by reacting the dichloromethane with hydrogen fluoride. In this case, difluoromethane (CH ２ F ２ , refrigerant number: R32) does not contain chlorine as a component and has an ozone depletion potential (ODP) of 0, and therefore can provide a preferable refrigerant from the perspective of protecting the ozone layer.

[0066] In the method for producing a fluorocarbon refrigerant according to this embodiment, the hydrocarbon is methane. For example, fluorocarbon refrigerants can be synthesized from hydrocarbons such as methane, ethane, propane, and butane. However, among these hydrocarbons, methane has the simplest structure. Therefore, in the process of synthesizing hydrocarbons from recovered carbon dioxide, methane can be synthesized with relatively little energy, thereby reducing the energy required for synthesis.

[0067] In the method for producing a fluorocarbon refrigerant according to this embodiment, a mixed refrigerant containing difluoromethane as one of its components is produced. When an existing heat pump apparatus is disposed of, the fluorocarbon refrigerant filled in the heat pump apparatus must also be disposed of. In this case, for example, by producing a mixed refrigerant from difluoromethane produced by the method for producing a fluorocarbon refrigerant according to this embodiment and a fluorocarbon refrigerant recovered from the existing heat pump apparatus, it is possible to reduce the labor and cost required to dispose of the fluorocarbon refrigerant in the existing heat pump apparatus.

[0068] In the fluorocarbon refrigerant production method of this embodiment, the mixed refrigerant is a mixed refrigerant of the difluoromethane and an olefin-based refrigerant. Olefin-based refrigerants (HFOs) generally have a lower global warming potential (GWP) than hydrofluorocarbons (HFCs) such as difluoromethane. Therefore, by producing a mixed refrigerant from difluoromethane produced by the fluorocarbon refrigerant production method of this embodiment and an olefin-based refrigerant, a mixed refrigerant with a low global warming potential can be provided.

[0069] In the method for producing a fluorocarbon refrigerant in this embodiment, the mixed refrigerant is a mixed refrigerant of difluoromethane and chlorodifluoromethane. When disposing of an existing heat pump device, the fluorocarbon refrigerant filled in the heat pump device must also be disposed of. In addition, in existing heat pump devices, hydrochlorofluorocarbons (HCFCs), such as chlorodifluoromethane (CHClF ２ In some cases, a fluorocarbon refrigerant (refrigerant number: R22) is used. In this case, for example, by producing a mixed refrigerant from difluoromethane produced by the method for producing a fluorocarbon refrigerant in this embodiment and chlorodifluoromethane recovered from an existing heat pump device, it is possible to reduce the labor and cost required to dispose of chlorodifluoromethane in the existing heat pump device.

[0070] In the method for storing a fluorocarbon refrigerant in this embodiment, the fluorocarbon refrigerant synthesized by the above-described method for producing a fluorocarbon refrigerant is filled and stored in a heat pump device. Therefore, by using the fluorocarbon refrigerant synthesized using recovered carbon dioxide as a heat medium in the heat pump device, the fluorocarbon refrigerant can be stably stored in the heat pump device for a period from the manufacture of the heat pump device to its disposal (e.g., 10 to 20 years). In other words, there is no need to prepare separate underground facilities or tanks for storing the recovered carbon dioxide, which reduces the labor and energy required to store and manage the recovered carbon dioxide.

[0071] In the method for storing a fluorocarbon refrigerant in this embodiment, a heat pump device is manufactured by filling the heat pump device with a fluorocarbon refrigerant synthesized by the above-described method for producing a fluorocarbon refrigerant. Therefore, by using the fluorocarbon refrigerant synthesized using recovered carbon dioxide as a heat medium within the heat pump device, the fluorocarbon refrigerant can be stably stored within the heat pump device for a period from the manufacture to the disposal of the heat pump device (e.g., 10 to 20 years). In other words, since there is no need to prepare separate underground facilities or tanks for storing the recovered carbon dioxide, a heat pump device can be provided that reduces the labor and energy required to store and manage the recovered carbon dioxide.

[0072] The carbon dioxide storage system 1 in this embodiment includes a carbon dioxide capture device 50 that captures carbon dioxide using an adsorbent, a carbon recycling fluorocarbon refrigerant synthesis device 60 that synthesizes a fluorocarbon refrigerant using the captured carbon dioxide as a raw material, and a heat pump device 70 that is filled with and stores the fluorocarbon refrigerant. Therefore, carbon dioxide can be captured from a gas to be treated, such as the atmosphere, indoor air, or factory exhaust, using an adsorbent, and a fluorocarbon refrigerant can be synthesized using the captured carbon dioxide as a raw material. The synthesized fluorocarbon refrigerant can be stored in the heat pump device 70. Because the fluorocarbon refrigerant is chemically stable, it can be used as a heat medium in the heat pump device 70, allowing the synthesized fluorocarbon refrigerant to be stably stored in the heat pump device 70 for a period from the manufacture of the heat pump device 70 to its disposal (e.g., 10 to 20 years). In other words, since there is no need to prepare separate underground facilities or tanks for storing the captured carbon dioxide, a carbon dioxide storage system 1 can be provided that reduces the labor and energy required to store and manage the captured carbon dioxide.

[0073] In the carbon dioxide storage system 1 of this embodiment, the carbon dioxide capture device 50 captures carbon dioxide using renewable energy. If fossil fuels or the like are used to capture carbon dioxide from the gas to be treated, the capture operation generates greenhouse gases such as carbon dioxide, which is undesirable from the perspective of preventing global warming, for example. By using renewable energy to capture carbon dioxide with the carbon dioxide capture device 50, the generation of greenhouse gases during the capture operation can be suppressed.

[0074] In the carbon dioxide storage system 1 of this embodiment, the carbon recycled fluorocarbon refrigerant synthesis device 60 synthesizes hydrocarbons from the recovered carbon dioxide and hydrogen, synthesizes dichloromethane by a radical reaction between the hydrocarbons and chlorine, and synthesizes difluoromethane by reacting the dichloromethane with hydrogen fluoride. In this case, difluoromethane (CH ２ F ２ , refrigerant number: R32) does not contain chlorine as a component and has an ozone depletion potential (ODP) of 0, so it is possible to provide a carbon dioxide storage system 1 that uses a refrigerant that is preferable from the perspective of protecting the ozone layer.

[0075] In the carbon dioxide storage system 1 of this embodiment, the hydrocarbon is methane. For example, it is possible to synthesize fluorocarbon refrigerants from hydrocarbons such as methane, ethane, propane, and butane. Of these hydrocarbons, methane has the simplest structure. Therefore, in the process of synthesizing hydrocarbons from recovered carbon dioxide, the hydrocarbon synthesis section 15 of the carbon recycling fluorocarbon refrigerant synthesis device 60 can synthesize methane with relatively little energy, thereby reducing the energy required for synthesis.

[0076] In the carbon dioxide storage system 1 of this embodiment, the refrigerant filled in the heat pump device 70 is a mixed refrigerant that contains difluoromethane as one of its components. When an existing heat pump device is disposed of, the fluorocarbon refrigerant filled in the heat pump device must also be disposed of. In this case, for example, a mixed refrigerant can be produced from difluoromethane produced by the carbon recycling fluorocarbon refrigerant synthesis device 60 and fluorocarbon refrigerant recovered from the existing heat pump device, and this mixed refrigerant can be filled and used in the heat pump device 70, thereby reducing the labor and cost required to dispose of the fluorocarbon refrigerant in the existing heat pump device.

[0077] In the carbon dioxide storage system 1 of this embodiment, the mixed refrigerant is a mixed refrigerant of the difluoromethane and an olefin-based refrigerant. The global warming potential (GWP) of olefin-based refrigerants (HFOs) is generally lower than that of hydrofluorocarbons (HFCs) such as difluoromethane. Therefore, by producing a mixed refrigerant from the difluoromethane produced by the carbon recycling fluorocarbon refrigerant synthesis unit 60 and the olefin-based refrigerant and filling this mixed refrigerant into the heat pump unit 70, it is possible to provide a carbon dioxide storage system 1 that uses a mixed refrigerant with a low global warming potential.

[0078] In the carbon dioxide storage system 1 of this embodiment, the mixed refrigerant is a mixed refrigerant of difluoromethane and chlorodifluoromethane. When disposing of an existing heat pump device, the fluorocarbon refrigerant filled in the heat pump device must also be disposed of. In addition, in existing heat pump devices, hydrochlorofluorocarbons (HCFCs), such as chlorodifluoromethane (CHClF ２In this case, for example, a mixed refrigerant can be produced from difluoromethane produced by carbon recycled fluorocarbon refrigerant synthesis unit 60 and chlorodifluoromethane recovered from an existing heat pump unit, and this mixed refrigerant can be filled into heat pump unit 70 for use, thereby providing carbon dioxide storage system 1 that can reduce the labor and cost required to dispose of chlorodifluoromethane in existing heat pump units.

[0079] In the carbon dioxide storage system 1 of this embodiment, the heat pump unit 70 includes a recovery port 86 that recovers the fluorocarbon refrigerant filled in the heat pump unit 70. In this case, when the heat pump unit 70 reaches the end of its service life and is to be disposed of, the filled fluorocarbon refrigerant can be recovered via the recovery port 86. This allows the fluorocarbon refrigerant to be recovered appropriately, and also reduces the effort required to recover the fluorocarbon refrigerant.

[0080] The technical scope of the present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure. For example, one or more concentrators (carbon dioxide concentrators) may be provided in the second outlet path 9. The concentrators increase the carbon dioxide concentration of the regeneration discharge fluid F2 by, for example, liquefaction separation, membrane separation, or adsorption separation. This increases the energy efficiency of the carbon dioxide separator 10. A concentrator may be provided in the first supply path 2. Alternatively, a concentrator may be provided between the carbon dioxide capture device 50 and the carbon recycled fluorocarbon refrigerant synthesis device 60.

[0081] In the above embodiment, the pressure reducer 8 is provided downstream of the heater 7, but this is not limited to this, and the pressure reducer 8 may be provided upstream of the heater 7 depending on the system specifications.

[0082] Known heat exchangers such as heaters and coolers can be used, including, for example, shell-and-tube heat exchangers, plate heat exchangers, coil heat exchangers, double-pipe heat exchangers, and spiral heat exchangers.

[0083] In the above embodiment, atmospheric air, indoor air, and factory exhaust gas are exemplified as gases to be treated, but nitrogen gas, hydrogen gas, oxygen gas, methane, etc. containing carbon dioxide may also be used as the gas to be treated.

[0084] In the above embodiment, hydrocarbons are synthesized from the recovered carbon dioxide and hydrogen, the hydrocarbons are subjected to a radical reaction with chlorine to synthesize dichloromethane, and the dichloromethane is reacted with hydrogen fluoride to synthesize difluoromethane, but the synthesis method is not limited to this. Other methods may be used to synthesize fluorocarbon refrigerants such as difluoromethane from the recovered carbon dioxide.

[0085] The catalysts in the hydrocarbon synthesis unit 15, the dichloromethane synthesis unit 16, and the fluorocarbon refrigerant synthesis unit 17 are not limited to the catalysts shown in the above embodiment, and may be changed to other appropriate catalysts depending on the system specifications.

[0086] In the above embodiment, difluoromethane is synthesized, but the present invention is not limited to this, and hydrofluorocarbons other than difluoromethane may also be synthesized.

[0087] REFERENCE SIGNS LIST 1 Carbon dioxide storage system 2 First supply path 3 Carbon dioxide adsorption section 3A First region 3B Second region 4 First discharge path 5 Regeneration fluid supply section 6 Second supply path 7 Heater 8 Pressure reducer 9 Second discharge path 10 Carbon dioxide separator 11 Compressor 12 Cooler 15 Hydrocarbon synthesis section 16 Dichloromethane synthesis section 17 Fluorocarbon refrigerant synthesis section 21 Blower 31 Adsorption region 32 Regeneration region 50 Carbon dioxide recovery device 60 Carbon recycled fluorocarbon refrigerant synthesis device 70 Heat pump device 80 Heat pump 81 Heater 82 Expansion device 83 Cooler 84 Compressor 85 Circulation path 86 Recovery port F1 Regeneration fluid F2 Regeneration discharge fluid F3 Discharge fluid F4 Refrigerant F5 Fluid F6 Fluid

Claims

1. A method for manufacturing a chlorofluorocarbon refrigerant, comprising a step of recovering carbon dioxide using an adsorbent, and a step of synthesizing a chlorofluorocarbon refrigerant using the recovered carbon dioxide as a raw material.

2. The method for manufacturing a chlorofluorocarbon refrigerant according to claim 1, wherein in the step of recovering the carbon dioxide, the carbon dioxide is recovered using renewable energy.

3. The method for manufacturing a chlorofluorocarbon refrigerant according to claim 1 or 2, wherein in the step of synthesizing the chlorofluorocarbon refrigerant, hydrocarbons are synthesized from the recovered carbon dioxide and hydrogen, dichloromethane is synthesized by subjecting the hydrocarbons and chlorine to a radical reaction, and difluoromethane is synthesized by reacting the dichloromethane with hydrogen fluoride.

4. The method for manufacturing a chlorofluorocarbon refrigerant according to claim 3, wherein the hydrocarbon is methane.

5. The method for manufacturing a chlorofluorocarbon refrigerant according to claim 3 or 4, wherein a mixed refrigerant containing difluoromethane as one of its components is manufactured.

6. The method for manufacturing a chlorofluorocarbon refrigerant according to claim 5, wherein the mixed refrigerant is a mixed refrigerant of difluoromethane and an olefin-based refrigerant.

7. The method for manufacturing a chlorofluorocarbon refrigerant according to claim 5, wherein the mixed refrigerant is a mixed refrigerant of difluoromethane and chlorodifluoromethane.

8. A method for storing a chlorofluorocarbon refrigerant, wherein the chlorofluorocarbon refrigerant synthesized by the method for manufacturing a chlorofluorocarbon refrigerant according to any one of claims 1 to 7 is filled into a heat pump device and stored.

9. A method for manufacturing a heat pump device, wherein the chlorofluorocarbon refrigerant synthesized by the method for manufacturing a chlorofluorocarbon refrigerant according to any one of claims 1 to 7 is filled into a heat pump device to manufacture the heat pump device.

10. A carbon dioxide storage system comprising a carbon dioxide recovery device that recovers carbon dioxide using an adsorbent, a carbon recycling chlorofluorocarbon refrigerant synthesis device that synthesizes a chlorofluorocarbon refrigerant using the recovered carbon dioxide as a raw material, and a heat pump device filled with and storing the chlorofluorocarbon refrigerant.

11. The carbon dioxide storage system according to claim 10, wherein the carbon dioxide recovery device recovers carbon dioxide using renewable energy.

12. The carbon recycling refrigerant synthesis device synthesizes hydrocarbons from the recovered carbon dioxide and hydrogen, synthesizes dichloromethane by subjecting the hydrocarbons and chlorine to a radical reaction, and synthesizes difluoromethane by reacting the dichloromethane with hydrogen fluoride. The carbon dioxide storage system according to claim 10 or 11.

13. The hydrocarbon is methane. The carbon dioxide storage system according to claim 12.

14. The refrigerant filled in the heat pump device is a mixed refrigerant containing the difluoromethane as one of its components. The carbon dioxide storage system according to claim 12 or 13.

15. The mixed refrigerant is a mixed refrigerant of the difluoromethane and an olefin-based refrigerant. The carbon dioxide storage system according to claim 14.

16. The mixed refrigerant is a mixed refrigerant of the difluoromethane and chlorodifluoromethane. The carbon dioxide storage system according to claim 14.

17. The heat pump device includes a recovery port for recovering the refrigerant filled in the heat pump device. The carbon dioxide storage system according to any one of claims 10 to 16.

Images