Carbon dioxide capture equipment

Abstract

To provide a carbon dioxide recovery device capable of efficiently recovering carbon dioxide desorbed from an adsorbent.SOLUTION: A carbon dioxide recovery device 1 comprises: a reactor 11 having an adsorbent 12 therein and performing an adsorption step of drawing gas containing carbon dioxide into the adsorbent 12 to adsorb the carbon dioxide, and a desorption step of heating the surroundings of the adsorbent 12 under a reduced pressure to desorb the carbon dioxide from the adsorbent 12; a carbon dioxide recovery pump 63 that applies suction force to the inside of the reactor 11 to recover the carbon dioxide desorbed in the desorption step; a heat exchanger (cooler) 64 arranged at a stage subsequent to the carbon dioxide recovery pump 63 and cooling the gas containing carbon dioxide and water vapor sucked by the carbon dioxide recovery pump 63 to perform gas-liquid separation; and a ballast pipe 170 for returning at least a portion of the carbon dioxide after gas-liquid separation, which has passed through the heat exchanger 64, to the inside of the carbon dioxide recovery pump 63 as ballast gas.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide capture device. [Background technology]

[0002] Conventionally, techniques for extracting predetermined components from gases have been known. Techniques of this type are described, for example, in Patent Document 1 and Patent Document 2. Patent Document 1 relates to a technique for recovering hydrocarbons from gases. Patent Document 2 relates to a technique for separating condensable gases and non-condensable gases from a mixed gas consisting of condensable gases and non-condensable gases, and recovering the condensable gases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-95679 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-288331 Summary of the Invention [Problem to be solved by the invention]

[0004] In a carbon dioxide capture device that captures carbon dioxide by drawing a gas such as air containing carbon dioxide into a reactor that holds an adsorbent and adsorbing it onto the adsorbent, and then desorbing the carbon dioxide adsorbed onto the adsorbent, a vacuum pump is used in the desorption process. Air generally contains moisture, and when an adsorbent that adsorbs water simultaneously with carbon dioxide is used, not only carbon dioxide but also water is desorbed from the adsorbent in the desorption process. The water is restored to its original pressure after passing through the vacuum pump and is recovered as a liquid. If the liquid water mixes with carbon dioxide during the desorption process, the purity of the carbon dioxide ultimately recovered may be reduced.

[0005] An object of the present invention is to provide a carbon dioxide recovery device that can recover carbon dioxide desorbed from an adsorbent with high efficiency. [Means for solving the problem]

[0006] (1) The present invention provides a carbon dioxide capture device (for example, the carbon dioxide capture device 1 described later) that includes a reactor (for example, the reactor 11 described later) that has an adsorbent (for example, the adsorbent 12 described later) therein and performs an adsorption step in which a gas containing carbon dioxide is drawn into the adsorbent to adsorb the carbon dioxide, and a desorption step in which the adsorbent is heated under reduced pressure to desorb the carbon dioxide from the adsorbent; a carbon dioxide capture pump (for example, the carbon dioxide capture pump 63 described later) that applies suction to the inside of the reactor to capture the carbon dioxide desorbed in the desorption step; a cooler (for example, the heat exchanger 64 described later) that is arranged downstream of the carbon dioxide capture pump and cools the gas containing carbon dioxide and water vapor drawn by the carbon dioxide capture pump to separate it into gas and liquid; and ballast piping (for example, the ballast piping 170 described later) that returns at least a portion of the carbon dioxide that has passed through the cooler after gas-liquid separation to the inside of the carbon dioxide capture pump as ballast gas.

[0007] (2) In the carbon dioxide capture device described in (1) above, the carbon dioxide capture pump has a compression chamber (e.g., compression chamber 151 described later) that performs a compression process to return the gas sucked from the reactor to atmospheric pressure, and the ballast piping may be connected to the compression chamber or a stage subsequent to the compression chamber inside the carbon dioxide capture pump.

[0008] (3) In the carbon dioxide recovery device described in (1) or (2) above, the flow path (e.g., flow path 160 described later) through which the gas of the cooling machine passes may be inclined so that the outlet (e.g., outlet 160b described later) is located lower than the inlet (e.g., inlet 160a described later).

[0009] (4) The carbon dioxide recovery device described in (1) or (2) above may further include a heat pump type heat source (for example, heat source 81 described later) that heats a heating heat medium to be supplied to the reactor and cools a cooling heat medium to be supplied to the reactor, and the heat medium that cools the cooling machine may be the cooling heat medium or the heating heat medium. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a carbon dioxide recovery device that can recover carbon dioxide desorbed from an adsorbent with high efficiency. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram showing a configuration relating to gas flow in a carbon dioxide capture device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a configuration relating to the flow of liquid in the carbon dioxide capture device of the present embodiment. [Figure 3] FIG. 2 is a schematic diagram showing a configuration relating to gas flow in a reactor of the carbon dioxide capture device of the present embodiment. [Figure 4] FIG. 2 is a schematic diagram showing a configuration relating to the flow of liquid in a reactor of the carbon dioxide capture device of the present embodiment. [Figure 5] 1 is a schematic diagram showing the configuration of a heat source circuit of a carbon dioxide recovery device according to an embodiment of the present invention. [Figure 6] 1 is a schematic diagram showing a configuration for introducing ballast gas with a high carbon dioxide concentration into a carbon dioxide capture pump of a carbon dioxide capture device of this embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] <Overall structure> Fig. 1 is a schematic diagram showing the configuration related to gas flow in a carbon dioxide capture device 1 according to one embodiment of the present invention. Fig. 2 is a schematic diagram showing the configuration related to liquid flow in the carbon dioxide capture device 1 of this embodiment. Note that the configuration related to liquid flow in the carbon dioxide capture device 1 is omitted in Fig. 1, and the configuration related to gas flow in the carbon dioxide capture device 1 is omitted in Fig. 2.

[0014] The carbon dioxide capture device 1 of this embodiment is applied to, for example, direct air capture (DAC) technology that captures carbon dioxide from the atmosphere in order to reduce the carbon dioxide concentration in the atmosphere. The carbon dioxide captured by the carbon dioxide capture device 1 is stored underground or reused as fuel or material.

[0015] As shown in Figures 1 and 2, the carbon dioxide recovery device 1 of this embodiment includes a reactor unit 10, a fan 61, a vacuum pump 62, a carbon dioxide recovery pump 63, a heat exchanger 64, a separator 65, a carbon dioxide tank 66, an inert gas tank 69, a heat exchanger 70, and a control device 90.

[0016] As shown in FIG. 1, the carbon dioxide recovery device 1 includes an adsorption line 101, a vacuum line 102, a carbon dioxide line 103, a circulation line 104, and an inert gas supply line 107 as gas flow paths.

[0017] The reactor unit 10 is configured by arranging a plurality of reactors 11 in parallel, each of which adsorbs carbon dioxide. In this embodiment, a total of 16 reactors 11 are arranged by a pair of left and right reactor units 10.

[0018] 3 is a schematic diagram showing a configuration related to gas flow in the reactor 11 of the carbon dioxide capture device 1 of this embodiment. The reactor 11 is a carbon dioxide capture reactor including an adsorbent 12, a first valve 21, a second valve 22, a third valve 23, a fourth valve 24, a pressure sensor 25, a carbon dioxide sensor 26, and a temperature sensor 27.

[0019] The adsorbent 12 is placed inside the reactor 11 to adsorb carbon dioxide. The adsorbent 12 is a particulate material that has the property of adsorbing carbon dioxide at low temperatures (for example, in the range of -30°C to 50°C) and desorbing (releasing) carbon dioxide at high temperatures (for example, in the range of 50°C to 110°C) when the ambient carbon dioxide concentration is low. Examples of such adsorbent 12 include solid amine carbon dioxide adsorbents formed by supporting amine on a porous material such as silica.

[0020] The first valve 21 is an on-off valve arranged at the connection between the reactor 11 and a carbon dioxide line 103 that captures carbon dioxide. A carbon dioxide capture pump 63 is arranged in the carbon dioxide line 103. The second valve 22 is an on-off valve arranged at the connection between the reactor 11 and a vacuum line 102 in which a vacuum pump 62 is arranged. The third valve 23 is an on-off valve arranged at the inlet that takes in air and the like into the reactor 11. The fourth valve 24 is an on-off valve arranged at the connection between the adsorption line 101 and the reactor 11.

[0021] The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are all controlled to open and close by a control device 90. The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are each configured by, for example, a normally open butterfly valve.

[0022] The pressure sensor 25 measures the internal pressure of the reactor 11. The carbon dioxide sensor 26 measures the carbon dioxide concentration inside the reactor 11. The temperature sensor 27 measures the temperature of the adsorbent 12. Measurement information from the pressure sensor 25, the carbon dioxide sensor 26, and the temperature sensor 27 is sent to the control device 90.

[0023] Returning to FIG. 1 , the adsorption line 101 and the fan 61 will be described. The adsorption line 101 branches off and is connected to each of the reactors 11. The fan 61 is located where the branched portions of the adsorption line 101 converge. When driven, the fan 61 generates a gas flow from "intake" to "exhaust" through the adsorption line 101 to the reactor 11. This supplies atmospheric air into the reactor 11. A carbon dioxide concentration sensor 611, a humidity sensor 612, and a temperature sensor 613 are located in the gas exhaust portion of the adsorption line 101, and measure the carbon dioxide, humidity, and temperature exhausted from the adsorption line 101. Measurement information from the carbon dioxide concentration sensor 611, the humidity sensor 612, and the temperature sensor 613 is sent to the control device 90.

[0024] The vacuum line 102 is branched and connected to each of the reactors 11. The vacuum pump 62 is disposed at the point where the branched portions of the vacuum line 102 converge. When the vacuum pump 62 is driven, it sucks gas from the inside of the reactor 11 through the vacuum line 102, bringing the inside of the reactor 11 into a vacuum state or a state close to a vacuum state.

[0025] The carbon dioxide line 103 branches off and is connected to each of the reactors 11. At the point where the branched portions of the carbon dioxide line 103 converge, a carbon dioxide recovery pump 63, a heat exchanger 64, a separator 65, and a carbon dioxide tank 66 are arranged.

[0026] The carbon dioxide capture pump 63 applies suction force to send the carbon dioxide flowing through the carbon dioxide line 103 to the carbon dioxide tank 66. A one-way valve 631 is arranged on the carbon dioxide line 103 upstream of the carbon dioxide capture pump 63. This prevents gas from flowing back from the heat exchanger 64 side to the reactor 11 side.

[0027] The heat exchanger 64 is an intercooler that cools the high-temperature gas containing carbon dioxide recovered from the reactor 11 and separates it into gas and liquid.

[0028] The water separated into gas and liquid in the heat exchanger 64 is recovered in a separator 65. A first valve 651 and a second valve 652 are disposed in the separator 65. The first valve 651 opens and closes a path communicating with the gas phase part of the separator 65. The second valve 652 opens and closes a path communicating with the liquid phase part of the separator 65.

[0029] In this embodiment, a ballast pipe 170 is connected to the carbon dioxide line 103 midway through the route, for introducing the gas with a high concentration of carbon dioxide after gas-liquid separation in the heat exchanger 64 as ballast gas into the carbon dioxide capture pump 63. Details of the configuration for introducing ballast gas into the carbon dioxide capture pump 63 will be described later with reference to FIG. 6.

[0030] The carbon dioxide tank 66 stores the carbon dioxide recovered through the carbon dioxide line 103. A tank valve 661 is arranged on the carbon dioxide line 103 upstream of the carbon dioxide tank 66. The tank valve 661 is controlled to open and close by the control device 90. In addition, various sensors such as a pressure sensor 662, a flow rate sensor 663, a humidity sensor 664, a temperature sensor 665, and a carbon dioxide concentration sensor 666 are arranged on the carbon dioxide line 103 between the tank valve 661 and the carbon dioxide tank 66. In addition, the carbon dioxide tank 66 is arranged with a pressure release valve 668 that releases pressure when the pressure reaches or exceeds a predetermined pressure.

[0031] Next, the inert gas tank 69 will be described. The inert gas tank 69 stores N2 as an inert gas supplied from an N2 gas cylinder 691 at a certain pressure or higher (for example, 980 kPa). A gas cylinder valve 692 is arranged between the inert gas tank 69 and the N2 gas cylinder 691. Also, the inert gas tank 69 is arranged with a pressure release valve 693 that releases the pressure when the pressure reaches a predetermined pressure or higher. A pressure sensor 694 is arranged inside the inert gas tank 69. Pressure information measured by the pressure sensor 694 is sent to the control device 90.

[0032] The inert gas tank 69 is connected to the carbon dioxide line 103 via an inert gas supply line 107. An inert gas valve 695 is disposed on the inert gas supply line 107. The inert gas valve 695 is controlled to open and close by the control device 90.

[0033] The heat exchanger 70 will be described with reference to Fig. 2. The heat exchanger 70 supplies thermal energy for heating the interior of each reactor 11 of the reactor unit 10 to a predetermined temperature when the reactor 11 performs the desorption step. The heat exchanger 70 also recovers unnecessary thermal energy when the reactor 11 performs the adsorption step.

[0034] The heat exchange device 70 of this embodiment includes a heat source circuit 80, a cold water line 111, a hot water line 112, a three-way valve 30, a bypass path 31, and a bypass valve 32.

[0035] The heat source circuit 80 mainly comprises a heat source device 81, a cold water tank 82, and a hot water tank 83, and performs heat exchange between a cooling heat medium flowing in a cold water line 111 and a heating heat medium flowing in a hot water line 112. Due to the heat transfer that occurs in the heat source circuit 80, the heat medium flowing in the cold water line 111 is cooled and the heat medium flowing in the hot water line 112 is heated. The heat medium is, for example, a liquid such as water. The detailed configuration of the heat source circuit 80 will be described later with reference to FIG. 5.

[0036] The cold water line 111 is a pipe through which cold water flows as a cooling heat medium. The cold water line 111 is branched and connected to the upstream and downstream sides of each reactor 11, connecting the cold water tank 82 to each reactor 11. Of the cold water lines 111, the line connected to the upstream side of each reactor 11 is referred to as a cold water supply line 111a, and the line connected to the downstream side of each reactor 11 is referred to as a cold water return line 111b.

[0037] The cold water supply line 111a is connected in parallel to the multiple reactors 11, and cold water can be supplied in parallel to each reactor 11. A first cold water circulation water pump 822 and a second cold water circulation water pump 823 are arranged in the cold water supply line 111a. The first cold water circulation water pump 822 and the second cold water circulation water pump 823 are, for example, cascade pumps.

[0038] Additionally, a circulation line 824 is arranged in the chilled water supply line 111a, returning from the downstream side of the second chilled water circulation water pump 823 to the upstream side. A safety valve 825 is arranged in this circulation line 824. The safety valve 825 relieves pressure when the pressure in the system between the second chilled water circulation water pump 823 and the chilled water line 111 exceeds a certain level, thereby suppressing a pressure increase. By arranging the safety valve 825, which relieves pressure in the event of an abnormality in the chilled water line 111, in parallel with the second chilled water circulation water pump 823, it is possible to achieve both a large flow rate circulation by the second chilled water circulation water pump 823 and safe operation.

[0039] The cold water recovery line 111b is also connected in parallel to the plurality of reactors 11, and the recovery of cold water after cooling can also be carried out in parallel for each reactor 11.

[0040] The hot water line 112 is a pipe through which hot water as a heat medium for heating flows. The hot water line 112 is branched and connected to the upstream and downstream sides of each reactor 11, and connects the hot water tank 83 to each reactor 11. Of the hot water lines 112, the line connected to the upstream side of each reactor 11 is referred to as a hot water supply line 112a, and the line connected to the downstream side of each reactor 11 is referred to as a hot water return line 112b.

[0041] The hot water supply line 112a is connected in parallel to the multiple reactors 11, and hot water can be supplied to each reactor 11 in parallel. A first hot water circulation water pump 832 and a second hot water circulation water pump 833 are arranged on the hot water supply line 112a. The first hot water circulation water pump 832 and the second hot water circulation water pump 833 are, for example, cascade pumps. By using a cascade pump that generates a large amount of heat when driven, it is possible to further heat the heat medium passing through the first hot water circulation water pump 832 and the second hot water circulation water pump 833.

[0042] Additionally, a circulation line 834 is arranged in the hot water supply line 112a, returning from the downstream side of the second hot water circulation water pump 833 to the upstream side. A safety valve 835 is arranged in this circulation line 834. The safety valve 835 relieves pressure when the pressure in the system between the second hot water circulation water pump 833 and the hot water line 112 exceeds a certain level, thereby suppressing a pressure increase. By arranging the safety valve 835, which relieves pressure in the event of an abnormality in the hot water line 112, in parallel with the second hot water circulation water pump 833, it is possible to achieve both a high flow rate circulation by the second hot water circulation water pump 833 and safe operation.

[0043] The hot water return line 112b is also connected in parallel to the plurality of reactors 11, and the hot water after heating can also be recovered in parallel for each reactor 11.

[0044] The three-way valve 30 is connected to the cold water line 111, the hot water line 112, and the reactor 11. The three-way valve 30 is disposed on each of the upstream and downstream sides of the reactor 11. The three-way valve 30 is configured to be able to select, by flow path switching, a cold water connection state in which the cold water line 111 is connected to the reactor 11, a hot water connection state in which the hot water line 112 is connected to the reactor 11, and a cut-off state in which the cold water line 111 and the hot water line 112 are cut off from the reactor 11.

[0045] The flow path switching of the three-way valve 30 is controlled by the control device 90. The heat medium is introduced into the reactor 11 through the three-way valve 30 arranged on the upstream side, and the heat medium is returned to the heat source device 81 side through the three-way valve 30 arranged on the downstream side.

[0046] The bypass path 31 is a flow path that allows the movement of a heat transfer medium between the reactors 11. The bypass path 31 connects two reactors 11. The reactors 11 connected by the bypass path 31 may be adjacent reactors or may be reactors 11 that are not adjacent but located apart.

[0047] The bypass valve 32 is disposed in the bypass path 31. The bypass valve 32 is disposed in each of the plurality of bypass paths 31. The bypass valve 32 is controlled to open and close by the control device 90.

[0048] 4 is a schematic diagram showing the configuration related to the flow of liquid in the reactor 11 of the carbon dioxide recovery device 1 of this embodiment. In the following description, the three-way valve 30 arranged upstream of the reactor 11 is referred to as the three-way valve 30a, and the three-way valve 30 arranged downstream of the reactor 11 is referred to as the three-way valve 30b.

[0049] 4, the reactor 11 includes an inlet-side flow path 33 connected to an inlet through which the heat transfer medium flows in, and an outlet-side flow path 34 connected to an outlet through which the heat transfer medium flows out. The bypass path 31 is connected to the outlet-side flow path 34 of the reactor 11 and is also connected to the inlet-side flow path 33 of another reactor 11.

[0050] A three-way valve 30a is disposed at the upstream end of the inlet flow path 33, and a three-way valve 30b is disposed at the downstream end of the outlet flow path 34. In the hot water connection state, the three-way valve 30a is connected to the hot water supply line 112a, and the three-way valve 30b is connected to the hot water return line 112b. In the cold water connection state, the three-way valve 30a is connected to the cold water supply line 111a, and the three-way valve 30b is connected to the cold water return line 111b.

[0051] The three-way valves 30a and 30b are configured to be able to adjust the flow rate. This flow rate adjustment function allows the flow rate of hot water to be adjusted when the hot water supply is connected, and the flow rate of cold water to be adjusted when the cold water supply is connected.

[0052] A temperature sensor 35 is disposed in the inlet-side flow path 33. A temperature sensor 36 and a flow rate sensor 37 are disposed in the outlet-side flow path 34. Measurement information from the temperature sensor 35, the temperature sensor 36, and the flow rate sensor 37 is transmitted to the control device 90.

[0053] Next, the control device 90 will be described. The control device 90 controls the operation of each part of the carbon dioxide capture device 1. The control device 90 controls the operation of devices used for adsorption and desorption of carbon dioxide, such as driving and stopping. The control device 90 selectively controls the timing of supplying a heat medium to each reactor 11 to heat or cool the reactors 11, so that the multiple reactors 11 repeatedly adsorb and desorb in time series.

[0054] The control device 90 controls the opening and closing of the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 provided in each reactor 11, and the opening and closing of each bypass valve 32. The control device 90 also controls the drive of the fan 61, the vacuum pump 62, the carbon dioxide capture pump 63, the first cold water circulation water pump 822, the second cold water circulation water pump 823, the first hot water circulation water pump 832, the second hot water circulation water pump 833, etc., and controls the opening and closing of the safety valve 825 and the safety valve 835.

[0055] The control device 90 is, for example, a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The control device 90 may be configured as a single device or as a plurality of devices. The control device 90 may also be configured using an electric circuit such as a relay.

[0056] <Carbon dioxide capture> Next, we will explain the control for capturing carbon dioxide by the control device 90. The carbon dioxide capture device 1 alternately performs an adsorption process in which the adsorbent 12 in the reactor 11 adsorbs carbon dioxide in a gas such as the air that has been taken in, and a desorption process in which the carbon dioxide adsorbed by the adsorbent 12 is desorbed, and stores the desorbed carbon dioxide in the carbon dioxide tank 66, thereby removing and capturing carbon dioxide from the air.

[0057] The adsorption process is a process in which carbon dioxide is adsorbed by the adsorbent 12 in the reactor 11. During the adsorption process, the third valve 23 and the fourth valve 24 of the reactor 11 are opened, and the first valve 21 and the second valve 22 are closed. In addition to controlling the opening and closing of the valves, the heat exchanger 70 controls the three-way valves 30a and 30b to a cold water connection state, allowing cold water to flow through the reactor 11 and cool the adsorbent 12 in the reactor 11. The fan 61 is driven, generating a gas flow from upstream to downstream, and gas containing carbon dioxide (e.g., atmospheric air) is drawn in through the third valve 23. The drawn gas passes through the adsorbent 12 in the reactor 11. At this time, the inside of the reactor 11 is cooled to room temperature (25°C) by the cold water, and the carbon dioxide in the gas is adsorbed by the adsorbent 12. Gases other than carbon dioxide, such as nitrogen and oxygen, are exhausted to the outside of the carbon dioxide recovery system 1 through the fourth valve 24 and the adsorption line 101.

[0058] The desorption step is a step of desorbing carbon dioxide from the adsorbent 12 in the reactor 11. In the desorption step, the first valve 21, the third valve 23, and the fourth valve 24 of the reactor 11 are closed, and the second valve 22 is opened. The vacuum pump 62 is operated to draw air into the reactor 11 and reduce the pressure to create a vacuum or near-vacuum state. In addition to controlling the opening and closing of the valves, the heat exchanger 70 controls the three-way valves 30a and 30b to a hot water connection state, and hot water flows through the reactor 11 to supply thermal energy and raise the temperature of the adsorbent 12 in the reactor 11. By controlling the temperature rise of the adsorbent 12, the adsorbent 12 is also heated to a predetermined temperature (e.g., 80°C) sufficient for the desorption step, and the carbon dioxide adsorbed in the adsorbent 12 is desorbed. Next, the second valve 22, the third valve 23, and the fourth valve 24 are closed, the first valve 21 is opened, and the carbon dioxide recovery pump 63 is driven, and the carbon dioxide desorbed through the carbon dioxide line 103 is stored in the carbon dioxide tank 66. In this embodiment, each step is controlled so that 12 of the 16 reactors 11 perform the adsorption step and the remaining four perform the desorption step.

[0059] <Heat source circuit> Next, the detailed configuration of the heat source circuit 80 will be described with reference to Fig. 5. Fig. 5 is a schematic diagram showing the configuration of the heat source circuit 80 of the carbon dioxide recovery device 1 of this embodiment.

[0060] As shown in Figure 5, the heat source circuit 80 of this embodiment includes a heat source device 81, a heat source high-temperature water circuit 85 including a hot water tank 83, a heat source low-temperature water circuit 86 including a cold water tank 82, and an equipment heat recovery circuit 87.

[0061] The heat source device 81 cools the heat medium introduced from the cold water tank 82 and heats the heat medium introduced from the hot water tank 83. The heat source device 81 is composed of a heat pump that transfers heat by utilizing the compression and expansion of gas.

[0062] The heat source high temperature water circuit 85 circulates hot water between the hot water tank 83 and the heat source device 81. The heat source high temperature water circuit 85 includes the hot water tank 83, a hot water side heat source supply line 221, and a hot water side heat source return line 222.

[0063] The hot water tank 83 is a heat storage device that has a heat insulating function and can store a heat medium. The capacity of the hot water tank 83 is preferably at least five times the maximum flow rate discharged by the hot water circulation water pump 831, which will be described later. By setting the capacity of the hot water tank 83 to be large relative to the flow rate of the heat medium, it is possible to suppress temperature fluctuations of the hot water (heat medium) during heat load fluctuations within a predetermined temperature range (for example, within ±5°C). In other words, the hot water tank 83 functions as a buffer for heat load fluctuations.

[0064] The hot water tank 83 is connected to the heat source device 81 via a hot water side heat source supply line 221 and a hot water side heat source return line 222. In addition, the hot water tank 83 is connected to a hot water supply line 112a and a hot water return line 112b.

[0065] The hot water side heat source supply line 221 is a path through which the heat medium flows from the hot water tank 83 to the heat source device 81. A hot water side circulation water pump 831 is arranged in the hot water side heat source supply line 221. The hot water side circulation water pump 831 is configured by, for example, a centrifugal pump or the like, and circulates the heat medium between the hot water tank 83 and the heat source device 81. The hot water side heat source return line 222 is a path through which the heat medium flows from the heat source device 81 to the hot water tank 83.

[0066] Next, we will explain the heat-source low-temperature water circuit 86. The heat-source low-temperature water circuit 86 circulates cold water between the cold water tank 82 and the heat source device 81. The heat-source low-temperature water circuit 86 includes the cold water tank 82, a cold water-side heat source supply line 121, a cold water-side heat source return line 122, and an equipment heat recovery circuit 87.

[0067] The cold water tank 82 is a heat storage device that has a heat insulating function and can store a heat medium. The capacity of the cold water tank 82 is preferably at least five times the maximum flow rate discharged by the cold water circulation water pump 821, which will be described later. By setting the capacity of the cold water tank 82 to be large relative to the flow rate of the heat medium, it is possible to suppress temperature fluctuations of the cold water (heat medium) during heat load fluctuations within a predetermined temperature range (for example, within ±5°C). In other words, the cold water tank 82 functions as a buffer for heat load fluctuations.

[0068] The cold water tank 82 is connected to the heat source device 81 via a cold water side heat source supply line 121 and a cold water side heat source return line 122. In addition, the cold water tank 82 is connected to a cold water supply line 111a and a cold water return line 111b.

[0069] The chilled water side heat source supply line 121 is a path through which the heat medium flows from the chilled water tank 82 to the heat source device 81. A chilled water side circulation water pump 821 is arranged in the chilled water side heat source supply line 121. The chilled water side circulation water pump 821 is configured by, for example, a centrifugal pump or the like, and circulates the heat medium between the chilled water tank 82 and the heat source device 81. The chilled water side heat source return line 122 is a path through which the heat medium flows from the heat source device 81 to the chilled water tank 82.

[0070] Next, we will explain the equipment heat recovery circuit 87. The equipment heat recovery circuit 87 cools target equipment such as the carbon dioxide recovery pump 63 and the heat exchanger 64, and also increases the temperature of the heat medium. The equipment heat recovery circuit 87 is connected in parallel to the heat-source low-temperature water circuit 86.

[0071] The equipment heat recovery circuit 87 of this embodiment has an equipment heat cooling line 126 whose upstream end is connected to the chilled water side heat source return line 122 and whose downstream end is connected to the chilled water side heat source supply line 121. The equipment heat cooling line 126 has a first branch line 126a that cools the carbon dioxide recovery pump 63 and a second branch line 126b that cools the heat exchanger 64.

[0072] The first branch line 126a is connected to the carbon dioxide capture pump 63, and uses cold water as a heat medium to cool the carbon dioxide capture pump 63. The cold water is heated by heat exchange with the carbon dioxide capture pump 63, and then merges with the second branch line 126b and is sent to the cold water side heat source supply line 121.

[0073] The second branch line 126b is connected to the heat exchanger 64 that generates heat of condensation of steam, and recovers the heat of condensation of steam by cooling the heat exchanger 64 with cold water as a heat medium. The cold water is heated by heat exchange with the heat exchanger 64 and then merges with the first branch line 126a, and is sent to the cold water side heat source supply line 121.

[0074] As described above, the equipment heat recovery circuit 87 recovers the exhaust heat of the vacuum pump 62 and the carbon dioxide recovery pump 63 into the heat medium to cool the target equipment, and the heat recovery makes it possible to cause the heat medium to flow into the heat source device 81 at a high temperature potential. By raising the temperature of the cold water to a predetermined temperature or higher, the temperature difference between the hot water and the cold water flowing into the heat source device 81 becomes smaller, and the COP can be increased.

[0075] <Introducing ballast gas into the carbon dioxide capture pump> Next, the connection structure of the carbon dioxide capture pump 63, heat exchanger 64, and separator 65 of this embodiment will be described with reference to Fig. 6. Fig. 6 is a schematic diagram showing a configuration for introducing ballast gas with a high carbon dioxide concentration into the carbon dioxide capture pump 63 of the carbon dioxide capture device 1 of this embodiment.

[0076] The carbon dioxide recovery pump 63 shown in FIG. 6 is a vacuum pump that compresses high-temperature gas containing carbon dioxide and superheated steam and returns it to atmospheric pressure.

[0077] The carbon dioxide capture pump 63 of this embodiment includes a compression chamber 151 that performs a compression process to compress high-temperature gas by rotating a screw 152, a bearing 153 that supports the screw 152, and a gearbox 154 that is arranged on the opposite side of the compression chamber 151 across the bearing 153.

[0078] The high-temperature gas containing carbon dioxide and superheated steam desorbed from the adsorbent 12 of the reactor 11 flows into the compression chamber 151 of the carbon dioxide recovery pump 63 through the carbon dioxide line 103, is compressed in the compression chamber 151, returns to atmospheric pressure, and is sent to the heat exchanger 64 from the outlet 155.

[0079] The heat exchanger 64 is connected to the outlet 155 of the carbon dioxide capture pump 63. A flow path 160 is formed inside the heat exchanger 64, through which high-temperature gas containing carbon dioxide and superheated steam discharged from the carbon dioxide capture pump 63 flows. The flow path 160 is inclined so that an inlet 160a side is higher and an outlet 160b side is lower. A pipe 161 is connected to the outlet 160b of the flow path 160 of the heat exchanger 64.

[0080] Cold water is introduced into the heat exchanger 64 as a cooling heat medium for cooling the high-temperature gas. The cold water introduced into the heat exchanger 64 flows outside the flow path 160 and exchanges heat with the high-temperature gas flowing inside the flow path 160. As a result of the heat exchange between the cold water and the high-temperature gas, the superheated steam contained in the high-temperature gas becomes a supercooled liquid. Meanwhile, the temperature of the cold water that is the other party in the heat exchange is raised. As described above, the cold water is a cooling heat medium that flows through the equipment heat recovery circuit 87, and the thermal energy obtained by cooling the high-temperature gas is used to raise the temperature of the cold water that flows into the heat source device 81.

[0081] The upstream end of the pipe 161 is connected to the outlet 160b of the flow path 160 of the heat exchanger 64, and the downstream side branches off to the separator 65 side and the carbon dioxide tank 66 side. In the following explanation, of the pipe 161, the pipe connected to the separator 65 side will be referred to as the separator side pipe 161a, and the pipe connected to the carbon dioxide tank 66 side will be referred to as the carbon dioxide side pipe 161b.

[0082] The separator-side pipe 161a is connected to a separator 65 located below the outlet 160b of the flow path 160 of the heat exchanger 64. The separator 65 is a catch tank that stores water that has been cooled in the heat exchanger 64 and turned from superheated steam into liquid.

[0083] The carbon dioxide side piping 161b is connected to the carbon dioxide tank 66. Gas containing carbon dioxide as a main component, from which moisture has been removed by gas-liquid separation in the heat exchanger 64, flows inside the carbon dioxide side piping 161b. In this embodiment, a ballast piping 170 connected to the upstream side of the heat exchanger 64 is connected to the carbon dioxide side piping 161b.

[0084] The ballast piping 170 is a ballast gas flow path for sending gas with a high carbon dioxide concentration flowing through the carbon dioxide side piping 161b as ballast gas to the inside of the carbon dioxide capture pump 63 located upstream of the heat exchanger 64. A compressor 171 is disposed in this ballast piping 170 for pressurizing the ballast gas from the carbon dioxide side piping 161b to the inside of the carbon dioxide capture pump 63. The compressor 171 is connected to, for example, the control device 90, and is driven based on a signal from the control device 90. The compressor 171 may have a function for being started by its own start switch.

[0085] The upstream end of the ballast piping 170 is connected to the carbon dioxide side piping 161b midway through the route before it reaches the carbon dioxide tank 66. The downstream end of the ballast piping 170 is connected to a rear portion of the compression chamber 151 inside the carbon dioxide capture pump 63. In this embodiment, the downstream end of the ballast piping 170 is connected to the bearing 153 located at the rearmost side of the compression chamber 151, and ballast gas is introduced into the carbon dioxide capture pump 63 so as to seal the gear box 154.

[0086] In the above embodiment, the upstream end of the ballast piping 170 is connected to the carbon dioxide side piping 161b, but the present invention is not limited to this configuration. For example, the upstream end of the ballast piping 170 may be connected to the carbon dioxide tank 66, and gas with a high carbon dioxide concentration stored in the carbon dioxide tank 66 may be returned to the carbon dioxide capture pump 63 as ballast gas.

[0087] Furthermore, in the above embodiment, the downstream end of the ballast piping 170 is configured to be connected to the rear side of the compression chamber 151 of the carbon dioxide capture pump 63, but this configuration is not limiting. For example, it may be arranged on the front side of the compression chamber 151, or it may be connected to the downstream side of the compression chamber 151 and arranged in a flow path before reaching the discharge port 155. In this way, the ballast gas mainly composed of carbon dioxide is preferably introduced at a position where the high-temperature gas returns to atmospheric pressure during the compression process or at a position after it has returned.

[0088] In the above embodiment, the heat medium introduced into the heat exchanger 64 is the cold water of the heat-source low-temperature water circuit 86, but this is not limiting. For example, the heat medium may be hot water of the heat-source high-temperature water circuit 85, which is introduced into the heat exchanger 64.

[0089] As described above, the carbon dioxide capture device 1 of this embodiment is equipped with a reactor 11 that has an adsorbent 12 therein and performs an adsorption process in which a gas containing carbon dioxide is drawn into the adsorbent 12 to adsorb the carbon dioxide, and a desorption process in which carbon dioxide is desorbed from the adsorbent 12 by heating the adsorbent 12 under reduced pressure, a carbon dioxide capture pump 63 that applies suction force to the inside of the reactor 11 to capture the carbon dioxide desorbed in the desorption process, a heat exchanger (cooler) 64 that is arranged downstream of the carbon dioxide capture pump 63 and cools the gas containing carbon dioxide and water vapor drawn by the carbon dioxide capture pump 63 to separate it into gas and liquid, and a ballast piping 170 that returns at least a portion of the carbon dioxide that has passed through the heat exchanger 64 after gas-liquid separation to the inside of the carbon dioxide capture pump 63 as ballast gas.

[0090] As a result, ballast gas with a high concentration of carbon dioxide is sent into the carbon dioxide capture pump 63, which reduces the vapor pressure inside the carbon dioxide capture pump 63 and makes it difficult for water to condense. This causes water to condense in a later process compared to when ballast gas is not sent, making it possible to control the timing of water liquefaction later. Furthermore, ballast gas is a gas whose main component is carbon dioxide, unlike other gases such as nitrogen and dry air, so it does not reduce the concentration of carbon dioxide captured in the carbon dioxide tank 66 at the later stage.

[0091] In addition, in this embodiment, the carbon dioxide capture pump 63 has a compression chamber 151 that performs a compression process to return the gas sucked from the reactor 11 to atmospheric pressure, and the ballast piping 170 is connected to the compression chamber 151 or a stage subsequent to the compression chamber 151 inside the carbon dioxide capture pump 63.

[0092] This allows the ballast gas to effectively prevent the generation of water due to condensation of water vapor during the compression process without reducing the carbon dioxide concentration in the subsequent stage.

[0093] In this embodiment, the flow path 160 through which the gas of the heat exchanger 64 passes is inclined so that the outlet 160b is positioned lower than the inlet 160a.

[0094] This allows the water that has been cooled and turned into liquid in the heat exchanger 64 to flow along the slope without remaining in the subsequent separator 65, further reducing the possibility that the concentration of recovered carbon dioxide will decrease due to mixing of water and carbon dioxide.

[0095] In addition, the carbon dioxide recovery device 1 of this embodiment further includes a heat pump type heat source device 81 that heats the heating heat medium supplied to the reactor 11 and cools the cooling heat medium supplied to the reactor, and the heat medium that cools the heat exchanger 64 is cold water (cooling heat medium) or hot water (heating heat medium).

[0096] This makes it possible to suppress a decrease in carbon dioxide concentration due to contamination of carbon dioxide with water, while simultaneously recovering the heat of condensation of the high-temperature gas in the heat exchanger 64 and the exhaust heat during cooling, thereby enabling the heat source device 81 to be operated efficiently.

[0097] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications. Furthermore, the effects described in the above embodiments are merely preferred effects, and the present invention is not limited to those described in the above embodiments. [Explanation of symbols]

[0098] 1. Carbon dioxide capture device 11. Reactor 12 Adsorbent 62 Vacuum pump 63 Carbon dioxide capture pump 64 Heat exchanger (cooler) 65 Separator 70 Heat exchange equipment 80 Heat source circuit 81 Heat source equipment 85 Heat source high temperature water circuit 86 Heat source low temperature water circuit 87 Equipment heat recovery circuit 151 Compression Chamber 160 flow channels 170 Ballast piping

Claims

1. a reactor having an adsorbent therein, which performs an adsorption step of drawing a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the adsorbent under a reduced pressure around the adsorbent to desorb the carbon dioxide from the adsorbent; a carbon dioxide recovery pump that applies suction force to the inside of the reactor in order to recover the carbon dioxide desorbed in the desorption step; a cooling machine disposed downstream of the carbon dioxide capture pump, which cools the gas containing carbon dioxide and water vapor sucked by the carbon dioxide capture pump to separate the gas into liquid and gas; a ballast pipe for returning at least a portion of the carbon dioxide after gas-liquid separation that has passed through the cooler to the inside of the carbon dioxide capture pump as ballast gas; and Equipped with a heat pump type heat source that heats the heating medium to be supplied to the reactor and cools the cooling medium to be supplied to the reactor, The carbon dioxide recovery device, wherein the heat medium that cools the cooling device is the cooling heat medium or the heating heat medium.

2. The carbon dioxide capture pump comprises: a compression chamber for performing a compression step of returning the gas drawn from the reactor to atmospheric pressure; The ballast piping is The carbon dioxide capture pump is connected to the compression chamber or a stage subsequent to the compression chamber. The carbon dioxide capture device according to claim 1 .

3. The flow path through which the gas passes in the cooler is inclined so that the outlet is located lower than the inlet. The carbon dioxide recovery device according to claim 1 or 2.

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