Carbon dioxide capture system

Abstract

By suppressing the influence of day and night and weather, and separating and capturing carbon dioxide stably at a high operating rate, and by converting the separated and captured carbon dioxide into a high-pressure gas or liquefaction that is easy to use, or by storing it underground, the annual amount of separated and captured carbon dioxide, or the amount of high-pressure gas or liquefied carbon dioxide obtained by separation and capture, or the amount of carbon dioxide stored underground can be increased. [Solution] A carbon dioxide separation and capture system comprising: a heat storage unit that stores solar heat and provides the heat; a carbon dioxide absorption liquid circulation and regeneration mechanism that uses the heat provided by the heat storage unit to heat an absorption liquid that has absorbed carbon dioxide contained in gas, releasing and separating and capturing the carbon dioxide while heating and regenerating the absorption liquid, and then causing it to absorb carbon dioxide contained in the gas again; and a carbon dioxide gas separation and capture function.

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide separation and capture system. [Background technology]

[0002] Patent Document 1 describes a thermal power generation system equipped with a carbon dioxide separation and capture device that includes a boiler that burns fossil fuel, a steam turbine driven by steam generated in the boiler, a condenser that condenses the steam that drives the steam turbine, a carbon dioxide separation and capture device that separates and captures carbon dioxide from exhaust gas from the boiler, and a solar thermal collector that collects solar heat to generate steam and supplies the steam to a reboiler of the carbon dioxide separation and capture device, wherein the thermal power generation system is configured so that when the amount of steam generated by the solar thermal collector falls below the amount of steam required by the reboiler, extracted steam extracted from the steam turbine is supplied to the reboiler, and a portion of the drainage generated by the reboiler is recovered in the condenser, and when the amount of steam generated by the solar thermal collector exceeds the amount of steam required by the reboiler, excess steam is recovered in the condenser, bypassing the reboiler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5704937 Summary of the Invention [Problem to be solved by the invention]

[0004] Solar thermal energy can be used to reduce carbon dioxide emissions resulting from the energy used to separate and capture carbon dioxide. For example, in chemical absorption methods, when heating an absorption solution containing carbon dioxide in a regeneration tower, steam generated by solar heat is used to heat the absorption solution. In this case, heating using solar heat, which does not emit carbon dioxide, reduces the carbon dioxide emissions resulting from the energy required to separate carbon dioxide. However, solar heat cannot be used at night or during inclement weather when sunlight is not available. That is, in all carbon dioxide separation and capture methods—chemical absorption, physical adsorption using an adsorbent, and membrane separation using a carbon dioxide separation membrane—the ability to stably separate and capture carbon dioxide regardless of the time of day or weather allows for stable operation of the equipment at a high operating rate and increases the annual amount of carbon dioxide separated and captured. However, if solar heat cannot be stored and used, stable continuous operation at a high operating rate regardless of the time of day or weather is not possible, making it impossible to increase the annual amount of carbon dioxide separated and captured. Furthermore, just like carbon dioxide separation and capture, a great deal of energy is consumed when compressing the separated and captured carbon dioxide gas and filling it into high-pressure gas cylinders, liquefying it, and injecting the liquefied carbon dioxide underground for underground storage. Therefore, stable operation day and night, regardless of the weather, will increase energy savings and the effectiveness of carbon dioxide reduction. However, if solar heat cannot be stored and used, there is the issue of not being able to stably convert the separated and captured carbon dioxide gas into high-pressure gas or liquefied carbon dioxide, or store it underground, at a high operating rate. The object of the present invention is to increase the annual amount of carbon dioxide gas separated and recovered, the amount of separated and recovered carbon dioxide gas converted into high-pressure gas, the amount of separated and recovered carbon dioxide gas liquefied, or the amount of separated and recovered carbon dioxide stored underground, by suppressing the effects of day and night and weather, and separating and recovering carbon dioxide stably at a high operating rate, and by converting the separated and recovered carbon dioxide into easy-to-use high-pressure gas or liquefied carbon dioxide, or by storing it underground. [Means for solving the problem]

[0005] The invention described in claim 1 includes a heat storage unit that stores solar heat and provides the heat, and a turbine that is driven by the heat provided by the heat storage unit, a gas compressor driven by the rotational driving force of the turbine; The heat provided by the heat storage unit is used to heat the absorbing solution that has absorbed the carbon dioxide contained in the gas, and the carbon dioxide is released and separated and recovered while the absorbing solution is heated and regenerated, and then Compressed by the gas compressor The carbon dioxide separation and capture system includes a carbon dioxide absorption liquid circulation and regeneration mechanism that absorbs carbon dioxide contained in gas, a carbon dioxide gas separation and capture function, and an injection section that injects the carbon dioxide separated and captured by the separation and capture function into a geological formation using the rotational power of the turbine. The invention described in claim 2 is a solar power generation system including: a heat storage unit that stores solar heat and provides the heat; and a turbine that is driven by the heat provided by the heat storage unit. a gas compressor driven by the rotational driving force of the turbine; The adsorbent that adsorbs the carbon dioxide contained in the gas is heated by the heat provided by the heat storage unit, and the carbon dioxide is released and separated and recovered while the adsorbent is heated and regenerated, and then, Compressed by the gas compressor It absorbs carbon dioxide contained in the gas. Arrival The carbon dioxide separation and capture system includes a carbon dioxide adsorbent heating and regeneration mechanism for separating and capturing carbon dioxide gas, a carbon dioxide gas separation and capture function, and an injection section that injects the carbon dioxide separated and captured by the separation and capture function into the geological formation using the rotational power of the turbine. The invention described in claim 3 includes a heat storage unit that stores solar heat and provides the heat, a turbine that is driven by the heat provided by the heat storage unit, and a gas compressor that is driven by the rotation of the turbine. and the suction pump and the gas compressor and the suction pump of between and an injection section that injects the carbon dioxide separated by the separation membrane into the geological formation by the rotational power of the turbine. The invention described in claim 4 is characterized in that a gas compressor is driven by the rotation of the turbine, and high-pressure gas containing carbon dioxide pressurized by the gas compressor is turned into fine bubbles and ejected into the carbon dioxide absorbing liquid described in claim 1. , a carbon dioxide capture system . The invention described in claim 5 is a gas compressor driven by the rotation of the turbine, and a high-pressure gas containing carbon dioxide pressurized by the gas compressor is fed to the carbon dioxide absorption device described in claim 2. Arrival The carbon dioxide separation and capture system is characterized by supplying a material into a container containing the material. The invention described in claim 6 is a device driven by the rotation of the turbine. Suction pump and the above Suction pump The carbon dioxide absorption method according to claim 2 Arrival The carbon dioxide absorption gas is provided on a carbon dioxide gas separation and recovery pipe of a container containing the material. Arrival Including materials The aforementioned This is a carbon dioxide separation and capture system that is characterized by desorbing carbon dioxide gas while changing the pressure inside the container and then suctioning and capturing it. The invention described in claim 7 is driven by the rotation of the turbine. and compress the gas gas Pressurization Compressor Further preparation , the gas Pressurization The compressor is a carbon dioxide separation and capture system characterized in that it further compresses and pressurizes the carbon dioxide gas separated and captured by any of the methods described in claims 1 to 6 to produce high-pressure carbon dioxide gas.

[0006] We also propose a carbon dioxide separation and capture system that includes a heat storage unit that stores solar heat and provides heat, an absorption refrigerator or adsorption refrigerator that is driven by the heat provided by the heat storage unit, and supplies the cold heat obtained by driving the refrigerator to cool a carbon dioxide absorption liquid, a carbon dioxide adsorbent, or a pressurized and compressed gas, thereby improving the carbon dioxide separation and capture performance or liquefying the separated and captured carbon dioxide. Furthermore, we propose a carbon dioxide separation and capture system characterized by comprising a heat storage unit that stores solar heat and provides heat, a turbine that is driven by the heat provided by the heat storage unit, a liquid feed pump that is driven by the rotation of the turbine, and the liquid feed pump circulating a carbon dioxide absorption liquid, or sending liquefied carbon dioxide that has been separated and recovered, or injecting and storing liquefied carbon dioxide that has been separated and recovered underground. [Effects of the Invention]

[0007] According to the present invention, carbon dioxide can be separated and recovered stably with a high operating rate by suppressing the effects of day and night and weather, and further, by converting the separated and recovered carbon dioxide into high-pressure gas or liquefied carbon dioxide, it can be filled into high-pressure gas cylinders or liquefied to make it suitable for transportation, or when the separated and recovered carbon dioxide is compressed and liquefied and injected underground for underground storage, it is possible to increase the annual amount of carbon dioxide gas separated and recovered, the amount of separated and recovered carbon dioxide gas converted into high-pressure gas, the amount of separated and recovered carbon dioxide gas liquefied, or the amount of separated and recovered carbon dioxide stored underground. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the overall configuration of a carbon dioxide separation and capture system according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing the overall configuration of a carbon dioxide separation and capture system according to a first modified example of the first embodiment. [Figure 3] FIG. 2 is a diagram showing the overall configuration of a carbon dioxide separation and capture system according to a second modification of the first embodiment. [Figure 4] FIG. 1 is a diagram showing the overall configuration of a carbon dioxide separation and capture system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. [Overall configuration of the carbon dioxide separation and capture system] Figure 1 is a diagram showing the overall configuration of a carbon dioxide separation and capture system 1 according to a first embodiment. The carbon dioxide separation and capture system 1 captures carbon dioxide from the atmosphere and injects and stores the carbon dioxide underground. The carbon dioxide separation and capture system 1 is placed at a position where the carbon dioxide is injected underground.

[0010] The carbon dioxide separation and capture system 1 according to the first embodiment includes a solar heat collection unit 10 and a drive unit 20. The carbon dioxide separation and capture system 1 also includes a separation unit 30, a liquefaction unit 40, and an injection unit 50.

[0011] The solar heat collecting unit 10 includes a heat collector 11 , a heat collection tube 12 , and a heat storage unit 13 . The heat collector 11 collects sunlight. The heat collector 11 is, for example, a mirror with a parabolic cross section, and collects sunlight at the focus of the parabola. The heat collection tube 12 receives the sunlight concentrated by the heat collector 11 and heats the heat medium flowing inside the tube. For example, synthetic oil or molten salt is used as the heat medium. The heat collection tube 12 is disposed at the focal position of the heat collector 11.

[0012] The heat storage unit 13 stores solar heat and provides heat. A heat medium flows inside the heat storage unit 13. Hereinafter, in this specification, the heat medium flowing inside the heat storage unit 13 will be referred to as the heat storage medium. As the heat storage medium in the heat storage unit 13, for example, synthetic oil or molten salt is used. The heat storage unit 13 includes a high-temperature tank 13a, a low-temperature tank 13b, a heat storage pipe 13c, and a heat exchanger 13d. The high-temperature tank 13a and the low-temperature tank 13b are containers capable of storing a heat storage medium. The heat storage pipe 13c connects the high temperature tank 13a and the low temperature tank 13b. The direction in which the heat storage medium flows in the heat storage pipe 13c is controlled by pumps provided in the high temperature tank 13a and the low temperature tank 13b, respectively. The heat exchanger 13d is provided in the heat storage pipe 13c between the high-temperature tank 13a and the low-temperature tank 13b. The heat collection pipe 12 passes through the heat exchanger 13d. The heat exchanger 13d exchanges heat between the heat storage medium flowing in the heat storage pipe 13c and the heat medium flowing in the heat collection pipe 12.

[0013] The drive unit 20 includes a steam generator 21, a turbine 22, a shaft 23, a steam condenser 24, piping 25, and a circulation pump 26. The steam generator 21, the turbine 22, and the steam condenser 24 are connected by a pipe 25, and water flows inside the pipe 25. A circulation pump 26 flows the water inside the pipe 25 toward the steam generator 21. The water inside the pipe 25 circulates by flowing through the steam generator 21, the turbine 22, and the steam condenser 24 in that order. In the first embodiment, water is used as the medium for rotating the turbine 22, but the turbine 22 may be rotated using another medium.

[0014] The piping 25 includes a first branch pipe 251 and a second branch pipe 252 . The first branch pipe 251 and the second branch pipe 252 are provided between the turbine 22 and the steam condenser 24. The first branch pipe 251 is provided closer to the turbine 22 than the second branch pipe 252. The first branch pipe 251 returns to the pipe 25 through a heating section 325, which will be described later. The second branch pipe 252 returns to the pipe 25 through a heat exchanger 42, which will be described later.

[0015] The steam generator 21 exchanges heat between the water in the pipe 25 and the heat medium in the heat collection pipe 12 to vaporize the water in the pipe 25 and generate steam. The turbine 22 is provided with blades that rotate when steam is received, and a shaft 23 that serves as a rotation axis for rotating the turbine 22 . The shaft 23 transmits the rotational force of the turbine 22 to various devices, and serves as a drive source for driving the various devices. More specifically, the shaft 23 drives a gas compressor 31, a carbon dioxide compressor 41, and an injection pump 51, which will be described later. The steam condenser 24 changes the state of the steam that rotates the turbine 22 into a liquid.

[0016] The separation unit 30 separates and recovers carbon dioxide from atmospheric air. The separation unit 30 includes a gas compressor 31 and a chemical absorption separation unit 32. The gas compressor 31 compresses the gas and supplies it to the chemical absorption separation unit 32. The gas compressor 31 is a rotary compressor. The drive unit of the gas compressor 31 is directly connected to the shaft 23 and rotates as the shaft 23 rotates. The shaft 23 and the drive unit of the gas compressor 31 may also be connected via a transmission. The transmission is, for example, a device that combines multiple gears with different numbers of teeth. The transmission changes the magnitude of the torque and rotation speed of the rotational power transmitted from the shaft 23 and transmits the rotational power to the gas compressor 31. Note that the gas compressor 31 may be a reciprocating compressor as long as it can use the rotational power of the shaft 23. In this case, the gas compressor 31 converts the rotational power of the shaft 23 into reciprocating motion, causing a piston to reciprocate and compress the gas. In the example shown, atmospheric air is supplied to the gas compressor 31, but biogas or combustion exhaust gas may also be supplied.

[0017] The chemical absorption separation unit 32 is an apparatus that separates carbon dioxide by chemical absorption and includes an absorption tower 321, a fine bubble supply pipe 322, a regeneration tower 323, a heating unit 325, and absorption liquid pipes 326 and 327. An absorbing liquid that absorbs carbon dioxide is stored in the absorption tower 321, and a fine bubble supply pipe 322 into which air compressed by the gas compressor 31 is injected is inserted. The absorbing liquid is, for example, an aqueous amine solution. The microbubble supply pipe 322 injects microbubbles into the absorbing solution. Here, the microbubbles are gas bubbles that are made into tiny bubbles so that carbon dioxide can be easily absorbed into the absorbing solution, such as nanobubbles with a size of less than 0.001 mm or microbubbles with a size of 0.001 mm or more but less than 0.1 mm. The regeneration tower 323 desorbs carbon dioxide from the absorbing solution that has absorbed carbon dioxide, thereby recovering the carbon dioxide. The heating section 325 heats the absorbing solution in the regenerator 323. A first branch pipe 251 is passed through the heating section 325, and steam that has done work in the turbine 22 is sent to the heating section 325. The absorbing solution in the regenerator 323 is heated by this steam. The absorbing liquid pipe 326 connects the absorption tower 321 and the regenerator 323. The absorbing liquid pipe 326 is provided with a liquid sending pump 326a that sends the absorbing liquid from the absorption tower 321 to the regenerator 323. The absorbing liquid pipe 327 connects the absorption tower 321 and the regenerator 323. The absorbing liquid pipe 327 is provided with a liquid transfer pump 327a that transfers the absorbing liquid from the regenerator 323 to the absorption tower 321. The liquid feed pump 326a and the liquid feed pump 327a are connected to the shaft 23 via a power transmission unit (not shown) and operate using the rotational power of the shaft 23. The liquid feed pump 326a and the liquid feed pump 327a are examples of liquid feed pumps.

[0018] The liquefaction unit 40 liquefies the carbon dioxide gas separated and recovered by the separation unit 30. The liquefaction unit 40 includes a carbon dioxide compressor 41, a heat exchanger 42, and a carbon dioxide cooler 43. The carbon dioxide compressor 41 is a rotary compressor. The drive section of the carbon dioxide compressor 41 is directly connected to the shaft 23, and rotates as the shaft 23 rotates. The shaft 23 and the drive section of the carbon dioxide compressor 41 may also be connected via a transmission. The carbon dioxide compressor 41 may be a reciprocating compressor as long as it can use the rotational power of the shaft 23. In this case, the carbon dioxide compressor 41 converts the rotational power of the shaft 23 into reciprocating motion, causing a piston to reciprocate and compress the gas. In the first embodiment, the rotating shaft of the turbine 22 and the rotating shaft of the carbon dioxide compressor 41 are connected coaxially, but the liquid pump and the carbon dioxide compressor may be operated under independent control by branching the steam generated from the steam generator 21 and supplying it to multiple turbines.

[0019] The heat exchanger 42 has the second branch pipe 252 passing through it, and is disposed in a regenerator 433 (described later) of the carbon dioxide cooler 43. The heat exchanger 42 exchanges heat with the absorbing solution in the regenerator 433, and heats the absorbing solution.

[0020] The carbon dioxide cooler 43 is an absorption refrigerator that cools carbon dioxide by using the heat of vaporization of water as a refrigerant. The carbon dioxide cooler 43 includes an evaporator 431, an absorber 432, a regenerator 433, and a condenser 434. The evaporator 431, the absorber 432, the regenerator 433, and the condenser 434 are connected via piping. A pipe through which carbon dioxide gas passes is passed through the evaporator 431. The water supplied to the evaporator 431 is evaporated while removing heat from the carbon dioxide gas. This causes the carbon dioxide gas to cool and become liquefied carbon dioxide. The absorber 432 absorbs the water vaporized in the evaporator 431 into an absorbing solution (for example, an aqueous lithium bromide solution). The absorber 432 transports the absorbing solution, which has absorbed water and has a lower concentration, to the regenerator 433. The regenerator 433 heats the absorbing solution using the heat exchanger 42 to generate steam. The absorbing solution, whose concentration has increased due to the generation of steam, is supplied to the absorber 432 again. The condenser 434 condenses the water vapor generated by the regenerator 433. The water liquefied by the condenser 434 is supplied to the evaporator 431 again.

[0021] The injection section 50 includes an injection pump 51 and an injection well 52 . The injection pump 51 applies energy to the liquefied separated carbon dioxide to inject the carbon dioxide into the formation. The injection pump 51 is, for example, a positive displacement pump. The drive unit of the injection pump 51 is directly connected to the shaft 23 and rotates as the shaft 23 rotates. The shaft 23 and the drive unit of the injection pump 51 may be connected via a transmission. The injection pump 51 may be any pump as long as it can use the rotational power of the shaft 23. The injection pump 51 may be one that imparts energy to the liquid by rotational motion or one that imparts energy to the liquid by reciprocating motion. When imparting energy to the liquid by reciprocating motion, the injection pump 51 converts the rotational power of the shaft 23 into reciprocating motion to reciprocate a piston. The injection pump 51 is an example of a liquid feed pump.

[0022] The injection well 52 is a pipe that extends underground, and extends deeper than the bedrock or stratum that is impermeable to carbon dioxide. The injection well 52 may extend to, for example, an oil reservoir or a natural gas reservoir, and inject the separated and recovered carbon dioxide into the cavity left after pumping up the oil or natural gas. The injection pump 51 is connected to the shaft 23. The injection pump 51 is driven by the rotation of the shaft 23. The injection pump 51 applies pressure to the liquefied carbon dioxide to inject the carbon dioxide into the ground through the injection well 52 and store it there.

[0023] [Carbon dioxide separation and capture operation] First, atmospheric air is supplied to the gas compressor 31 of the separation section 30. The gas compressor 31 compresses the supplied air and supplies the compressed air to the chemical absorption separation section 32. The chemical absorption separation section 32 supplies the supplied air into the absorption tower 321 via a fine bubble supply pipe 322. A portion of the carbon dioxide in the air supplied to the absorption tower 321 is absorbed by the absorption liquid. Hereinafter, the absorption liquid that has absorbed carbon dioxide may be referred to as a rich absorption liquid. The absorption tower 321 releases the air, from which carbon dioxide has been absorbed and whose carbon dioxide concentration has been reduced, into the atmosphere.

[0024] The absorption tower 321 supplies the rich absorbing liquid to the regeneration tower 323. In the regeneration tower 323, the rich absorbing liquid is heated to separate the absorbing liquid from carbon dioxide. The separated carbon dioxide is supplied to the liquefaction unit 40. The regenerated absorbing liquid is supplied again to the absorption tower 321 and circulated. The chemical absorption separation unit 32 is an example of a circulation regeneration mechanism for the carbon dioxide absorbing liquid. The chemical absorption separation unit 32 is also an example of a carbon dioxide gas separation and recovery function. Even if the absorbing liquid has been heated and turned into a regenerated absorbing liquid, if the temperature of the absorbing liquid is high, its absorption performance will be reduced when absorbing carbon dioxide again. Therefore, a cooler may be provided to cool the regenerated absorbing liquid. For example, cold energy may be generated in the carbon dioxide cooler 43, and this cold energy may be used to cool the regenerated absorbing liquid.

[0025] The carbon dioxide gas supplied to the liquefaction unit 40 is compressed by the carbon dioxide compressor 41 to a pressure higher than the pressure at the triple point of carbon dioxide. The compressed carbon dioxide gas is cooled and liquefied by the carbon dioxide cooler 43 while maintaining the pressure.

[0026] The liquefied carbon dioxide is transported to the injection section 50. The liquefied carbon dioxide transported to the injection section 50 is pumped to an injection well 52 by an injection pump 51 of the injection section 50. The liquefied carbon dioxide is injected into an underground geological formation connected to the injection well 52 and stored underground.

[0027] [Operation of the heat storage unit] When excess heat is generated in excess of the amount of heat required to generate steam in the steam generator 21 during a period when sunlight is irradiating the heat collector 11, the heat storage unit 13 stores the excess solar heat. Furthermore, the heat storage unit 13 supplies the stored heat to the drive unit 20 during a period when sunlight is not irradiating the heat collector 11. Note that the period when sunlight is irradiating the heat collector 11 here refers to, for example, a sunny daytime period when sunlight is irradiating the ground. Note that the period when sunlight is not irradiating the heat collector 11 here refers to, for example, the nighttime period after sunset until sunrise the next day, or a period when the weather is cloudy or rainy.

[0028] When the heat storage unit 13 stores heat, the heat storage medium contained in the low-temperature tank 13b is moved to the high-temperature tank 13a. At this time, the heat storage medium passes through the heat exchanger 13d provided between the low-temperature tank 13b and the high-temperature tank 13a. In the heat exchanger 13d, the heat storage medium is heated by exchanging heat with the heat medium in the heat collection pipe 12. The heated and high-temperature heat storage medium flows into the high-temperature tank 13a and is stored there.

[0029] Furthermore, during periods when solar heat is not supplied to the heat collector 11, the heat storage unit 13 supplies the heat stored therein to the water circulating through the drive unit 20. More specifically, the heat storage unit 13 flows the heat storage medium from the high-temperature tank 13a to the low-temperature tank 13b, and exchanges heat with the heat medium in the heat collection tube 12 in the heat exchanger 13d. The heat medium in the heat collection tube 12 is heated by the heat storage medium and reaches a high temperature. The heat medium in the heat collection tube 12 flows to the steam generator 21 and heats the water in the pipe 25. The water in the pipe 25 is heated by the heat medium in the heat collection tube 12 and turns into steam, which rotates the turbine 22. In other words, the turbine 22 is driven by the heat provided by the heat storage section 13. The rotation of the turbine 22 rotates the shaft 23, which drives various devices that use the shaft 23 as a drive source. More specifically, the gas compressor 31, the carbon dioxide compressor 41, and the injection pump 51 are rotated. In other words, the gas compressor 31 is driven by the rotation of the turbine 22. The carbon dioxide compressor 41 is driven by the rotation of the turbine 22. The injection pump 51 is driven by the rotation of the turbine 22.

[0030] Moreover, the heat supplied from the heat storage section 13 is supplied to the heating section 325 via the first branch pipe 251. The heating section 325 heats the absorbing liquid, thereby separating and recovering carbon dioxide. Furthermore, the heat supplied from the heat storage section 13 is supplied to the heat exchanger via the second branch pipe 252. The carbon dioxide cooler 43 uses the heat exchanger to cool and liquefy the carbon dioxide gas.

[0031] With this configuration, the carbon dioxide separation and capture system 1 according to the first embodiment can use solar heat to separate and capture carbon dioxide and store it underground at a high operating rate, even at night, during sunset and sunrise, and even during the daytime, even on rainy or cloudy days.

[0032] In addition, when the amount of solar heat collected by the heat collector 11 exceeds the amount of steam generated by the steam generator 21 required to operate the carbon dioxide separation and capture system 1, and excess solar heat is collected and stored in the heat storage section 13, the method of circulating the heat medium in the heat collection tube 12 is to store the excess heat in the heat storage section 13 via a circulation path that passes through the heat collector 11 and the heat exchanger 13d in addition to the circulation path that passes through the heat collector 11 and the steam generator 21, by controlling the opening and closing valves provided on the branch flow paths upstream and downstream of the heat exchanger 13d, and during periods when excess heat is generated, opening the valves on the circulation flow paths upstream and downstream of the heat exchanger 13d that were closed during periods when excess heat is not generated, and circulating the heat medium in both the circulation flow path that passes through the steam generator 21 and the circulation flow path that passes through the heat exchanger 13d, so that the excess solar heat can be stored in the heat storage section 13 while the carbon dioxide separation and capture system 1 is operating.

[0033] Furthermore, when the heat stored in the heat storage section 13 is supplied to the water circulating through the drive section 20 during the period when solar heat is not supplied to the heat collector 11, the method of circulating the heat medium in the heat collection tube 12 is such that, of the circulation path passing through the heat collector 11 and the circulation path passing through the steam generator 21, the heat medium is not circulated in the former circulation path, and the heat medium is selectively circulated only in the latter circulation path passing through the steam generator 21, by controlling the opening and closing valves provided on the branch flow paths upstream and downstream of the heat exchanger 13d, and during the period when solar heat is not supplied to the heat collector 11, the valve of the circulation path passing through the heat collector 11 is closed and only the valve that forms the circulation path passing only through the heat exchanger 13d and the steam generator 21 is opened, thereby selectively circulating the heat medium only in the circulation path passing through the steam generator 21, thereby making it possible to efficiently use the heat stored in the heat storage section 13 for steam generation.

[0034] Furthermore, in carbon dioxide separation and capture system 1, the force of rotation of shaft 23 is used to drive gas compressor 31, carbon dioxide compressor 41, and injection pump 51. However, shaft 23 does not necessarily need to drive all three of gas compressor 31, carbon dioxide compressor 41, and injection pump 51, and may drive only one of them, and although second branch pipe 252 is provided downstream of first branch pipe 251 in the direction in which water flows in piping 25, it may also be provided upstream of first branch pipe 251.

[0035] [Modification 1 of the First Embodiment] FIG. 2 is a diagram showing the overall configuration of a carbon dioxide separation and capture system 2 according to a first modification of the first embodiment. The first modification of the first embodiment differs from the first embodiment in that the chemical absorption separation section 32 of the separation section 30 is replaced with a physical adsorption separation section 34. Note that the same functions as those in the first embodiment are designated by the same reference numerals, and their description will be omitted here.

[0036] The carbon dioxide separation and capture system 2 includes a solar heat collection unit 10, a drive unit 20, a separation unit 230, a liquefaction unit 40, and an injection unit 50. The separation section 230 includes a gas compressor 31 and a physical adsorption separation section . The physical adsorption separation unit 34 includes an adsorption tank 341 , a heat exchanger 342 , and a suction pump 343 .

[0037] The adsorption tank 341 stores an adsorbent that adsorbs carbon dioxide inside the tank. Examples of the adsorbent include zeolite and activated carbon. The adsorption tank 341 also includes an outlet 341a that can be opened and closed. The outlet 341a is used to replace the gas inside the adsorption tank 341. The heat exchanger 342 heats the inside of the adsorption tank 341. Steam that has done work in the turbine 22 is sent to the heat exchanger 342 via the first branch pipe 251. The inside of the adsorption tank 341 is heated by the heat of this steam. Suction pump 343 reduces the pressure inside adsorption tank 341. Suction pump 343 includes gear 343a that is attached to shaft 23 and obtains rotational power from shaft 23, and rotating shaft 343b that transmits the rotational power of gear 343a to suction pump 343. Rotating shaft 343b is connected to a drive unit of suction pump 343, and suction pump 343 is driven by the rotational power of rotating shaft 343b.

[0038] [Carbon dioxide separation and capture operation] In physical adsorption, carbon dioxide is separated from other gases by utilizing a pressure difference or a temperature difference. Specifically, first, the exhaust port 341a of the adsorption tank 341 is closed, and the gas compressor 31 is driven. Air compressed by the gas compressor 31 is supplied to the adsorption tank 341, increasing the pressure inside the adsorption tank 341. As the pressure inside the adsorption tank 341 increases, the adsorbent adsorbs carbon dioxide. Next, the exhaust port 341a is opened, and the gas with a reduced carbon dioxide concentration is discharged. Then, after closing the exhaust port 341a, the suction pump 343 is driven to reduce the pressure inside the adsorption tank 341. As the pressure inside the adsorption tank 341 decreases, carbon dioxide is desorbed from the adsorbent. The desorbed carbon dioxide is then recovered.

[0039] In addition, adsorbents generally have a higher adsorption rate at low temperatures and a lower adsorption rate at high temperatures. Therefore, the adsorption tank 341 may be heated when desorbing carbon dioxide from the adsorbent. Heating the adsorbent desorbs more carbon dioxide, allowing the adsorbent to adsorb more carbon dioxide when reused compared to when the adsorbent is not heated. The adsorption tank 341 is heated by supplying steam to the heat exchanger 342 via the first branch pipe 251. The adsorption tank 341 may also be cooled when the adsorbent adsorbs carbon dioxide. For example, cold energy may be generated using a carbon dioxide cooler 43 and supplied to the adsorption tank 341. The physical adsorption separation unit 34 is an example of a thermal regeneration mechanism for the carbon dioxide adsorbent and an example of a carbon dioxide gas separation and recovery function.

[0040] As described above, in the first modification of the first embodiment, the pressure inside the adsorption tank 341 can be changed to separate carbon dioxide using the gas compressor 31 driven by heat supplied from the heat storage unit 13 and the suction pump 343. Furthermore, the temperature inside the adsorption tank 341 can be changed by utilizing the heat supplied from the heat storage unit 13, allowing for efficient separation of carbon dioxide.

[0041] In the first modification of the first embodiment, it has been described that carbon dioxide is separated using both pressure changes and temperature changes in the adsorption tank 341. However, carbon dioxide may be separated using only one of the pressure changes and temperature changes in the adsorption tank 341.

[0042] [Modification 2 of the First Embodiment] FIG. 3 is a diagram showing the overall configuration of a carbon dioxide separation and capture system 3 according to a second modification of the first embodiment. The second modification of the first embodiment differs from the first embodiment in that the chemical absorption separation section 32 is replaced with a separation membrane module 36. Note that the same functions as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted here.

[0043] The carbon dioxide separation and capture system 2 includes a solar heat collection unit 10, a drive unit 20, a separation unit 330, a liquefaction unit 40, and an injection unit 50. The separation section 330 includes a gas compressor 31 and a separation membrane module 36 .

[0044] The separation membrane module 36 includes a separation membrane 361 and a suction pump 362 . The separation membrane 361 selectively allows carbon dioxide to pass through. The separation membrane 361 is disposed inside the tube of the tubular separation membrane module 36, and divides the inside of the tube into an upstream side and a downstream side. The suction pump 362 is provided downstream of the separation membrane 361 and reduces the air pressure downstream inside the separation membrane module 36. The suction pump 362 includes a gear 362a that is provided on the shaft 23 and obtains the rotational power of the shaft 23, and a rotating shaft 362b that transmits the rotational power of the gear 362a to the suction pump 362. The rotating shaft 362b is connected to a drive unit of the suction pump 362, and the suction pump 362 is driven by the rotational power of the rotating shaft 362b. Examples of the suction pump 362 include a vacuum pump and a decompression pump.

[0045] [Carbon dioxide separation and capture process] First, atmospheric air is supplied to the gas compressor 31 of the separation section 30. The gas compressor 31 compresses the supplied air to make the pressure of the air higher than atmospheric pressure. The magnitude of the pressure of the air compressed by the gas compressor 31 is set appropriately depending on the performance of the separation membrane, etc. Also, the suction pump 362 is driven to reduce the pressure on the downstream side of the separation membrane 361. This creates a pressure difference between the upstream and downstream sides of the separation membrane 361, causing the carbon dioxide gas to pass through the separation membrane and move downstream. The carbon dioxide that has moved downstream is recovered and supplied to the liquefaction unit 40. Meanwhile, the air that remains on the upstream side of the separation membrane 361 and has a reduced carbon dioxide concentration is discharged into the atmosphere.

[0046] Second Embodiment FIG. 4 is a diagram showing the overall configuration of a carbon dioxide separation and capture system 4 according to the second embodiment. The second embodiment differs from Modification 2 of the first embodiment in that it further includes a renewable energy power generation unit 60. Also, a liquefaction unit 240 of the second embodiment differs from the liquefaction unit 40 of the first embodiment in that the carbon dioxide cooler 43 is replaced by a turbo chiller 73. Note that the same functions as those of the first embodiment are designated by the same reference numerals, and their description will be omitted here.

[0047] Examples of the renewable energy power generation unit 60 include solar power generation, solar thermal power generation, wind power generation, geothermal power generation, and water current power generation. In the second embodiment, solar power generation will be described as an example. The renewable energy power generation unit 60 may be provided with an external power transmission facility and supply electric power to the outside, or may supply electric power only to the carbon dioxide separation and capture system 4.

[0048] The renewable energy power generation unit 60 includes a solar power generation device 61 and a power storage unit 62. The solar power generation device 61 may be a solar cell that generates electricity when irradiated with sunlight. There is no particular limitation on the type of solar cell, but examples include silicon-based solar cells and compound-based solar cells. The electricity generated by the solar power generation device 61 is supplied to various devices in the carbon dioxide separation and capture system 4. The power storage unit 62 is a chargeable and dischargeable device, and may be, for example, a storage battery. The power storage unit 62 stores a portion of the power generated by the solar power generation device 61. The power storage unit 62 supplies the stored power to various devices in the carbon dioxide separation and capture system 4.

[0049] The liquefaction section 240 includes a carbon dioxide compressor 41 and a turbo refrigerator 73 . The turbo chiller 73 has an internal compressor that compresses a refrigerant using the compressor to execute a refrigeration cycle. Carbon dioxide gas cooled by the turbo chiller 73 is liquefied to become liquefied carbon dioxide. In the second embodiment, the compressor of the turbo chiller 73 is driven by power supplied by the renewable energy power generation unit 60. During periods when sunlight is not irradiated, such as at night, the power storage unit 62 supplies power to the turbo chiller 73.

[0050] The carbon dioxide separation and capture system 4 according to the second embodiment can separate and capture atmospheric carbon dioxide from the air surrounding the system and store it underground, even in places where there are no power lines, such as deserts.

[0051] 〔others〕 In this embodiment, an absorption refrigerator is used as the carbon dioxide cooler 43, but an adsorption refrigerator may also be used. In this embodiment, carbon dioxide is separated and recovered from the atmosphere, but carbon dioxide may also be separated from biogas discharged from a biomass fermenter, for example. The arrangement of the mirrors that collect solar heat is not particularly limited. For example, a large number of flat mirrors may be arranged on the ground to surround the tower, with the heat collector 11 attached to the top of the tower. In this embodiment, the injection pump 51 is used to store liquefied carbon dioxide in the stratum, but the liquefied carbon dioxide may also be used as a raw material gas for commercial and industrial use. In this case, the injection pump 51 may be used to fill a carbon dioxide cylinder with high-pressure carbon dioxide gas, or to fill a tank truck or the like with liquefied carbon dioxide. The recovered carbon dioxide may also be solidified and used as dry ice. [Explanation of symbols]

[0052] 1, 2, 3, 4... Carbon dioxide separation and capture system, 10... Solar heat collection section, 11... Heat collector, 12... Heat collection tube, 13... Heat storage section, 13a... High temperature tank, 13b... Low temperature tank, 13c... Heat storage tube, 13d... Heat exchanger, 20... Drive section, 21... Steam generator, 22... Turbine, 23... Shaft, 24... Steam condenser, 25... Piping, 30... Separation section, 31... Gas compressor, 32... Chemical absorption separation section, 34... Physical adsorption separation section, 36... Separation membrane module, 40... Liquefaction section, 41... Carbon dioxide compressor, 42... Heat exchanger, 43... Carbon dioxide cooler, 50... Injection section, 51... Injection pump, 52... Injection well, 60... renewable energy power generation unit, 61... solar power generation device, 62... power storage unit, 73... turbo chiller, 230... separation unit, 240... liquefaction unit, 251... first branch pipe, 252... second branch pipe, 321... absorption tower, 322... fine bubble supply pipe, 323... regeneration tower, 325... heating unit, 326a, 326b... liquid feed pump, 330... separation unit, 341... absorption tank, 341a... discharge port, 342... heat exchanger, 343... suction pump, 344... shaft, 346b... rotating shaft, 361... separation membrane, 362... suction pump, 362a... gear, 431... evaporator, 432... absorber, 433... regenerator, 434... condenser

Claims

1. a heat storage unit that stores solar heat and provides the heat; a turbine driven by the heat provided by the heat storage unit; a gas compressor driven by the rotational driving force of the turbine; a carbon dioxide absorbing liquid circulation regeneration mechanism that uses heat provided by the heat storage unit to heat an absorbing liquid that has absorbed carbon dioxide contained in the gas, and then heats and regenerates the absorbing liquid while releasing and separating and recovering the carbon dioxide, and then causes the absorbing liquid to again absorb carbon dioxide contained in the gas compressed by the gas compressor; and a carbon dioxide gas separation and recovery function; an injection unit that injects the carbon dioxide separated and recovered by the separation and recovery function into a geological formation using the rotational power of the turbine; A carbon dioxide separation and capture system.

2. a heat storage unit that stores solar heat and provides the heat; a turbine driven by the heat provided by the heat storage unit; a gas compressor driven by the rotational driving force of the turbine; a carbon dioxide adsorbent heating and regeneration mechanism that uses heat provided by the heat storage unit to heat the adsorbent that has adsorbed carbon dioxide contained in the gas, and then heats and regenerates the adsorbent while releasing and separating and recovering the carbon dioxide, and then causes the adsorbent to again adsorb carbon dioxide contained in the gas compressed by the gas compressor; and a carbon dioxide gas separation and recovery function; an injection unit that injects the carbon dioxide separated and recovered by the separation and recovery function into a geological formation using the rotational power of the turbine; A carbon dioxide separation and capture system.

3. a heat storage unit that stores solar heat and provides the heat; a turbine driven by the heat provided by the heat storage unit; a gas compressor and a suction pump driven by the rotation of the turbine; a carbon dioxide separation membrane provided between the gas compressor and the suction pump; an injection unit that injects the carbon dioxide separated by the separation membrane into the formation using the rotational power of the turbine; A carbon dioxide separation and capture system.

4. a gas compressor driven by the rotation of the turbine; A carbon dioxide separation and capture system, characterized in that high-pressure gas containing carbon dioxide, which has been pressurized by the gas compressor, is turned into fine bubbles and then ejected into the carbon dioxide absorbing liquid according to claim 1.

5. a gas compressor driven by the rotation of the turbine; A carbon dioxide separation and capture system, characterized in that high-pressure gas containing carbon dioxide pressurized by the gas compressor is supplied into a container containing the carbon dioxide adsorbing material according to claim 2.

6. a suction pump driven by the rotation of the turbine; A carbon dioxide separation and capture system, characterized in that the suction pump is provided on a carbon dioxide gas separation and capture pipe of a container containing the carbon dioxide adsorbent according to claim 2, and the carbon dioxide gas is desorbed and then sucked and recovered while changing the pressure inside the container containing the carbon dioxide adsorbent.

7. The turbine further includes a gas compressor that is driven by the rotation of the turbine to compress the gas. The gas compression compressor further compresses and pressurizes the carbon dioxide gas separated and recovered by any one of the methods according to claims 1 to 6 to produce high-pressure carbon dioxide gas. Carbon dioxide capture system.

Images