Carbon dioxide recovery apparatus
Patent Information
- Application Number
- PCT/JP2025/011477
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2026-10-01
Smart Images
Figure JP2025011477_01102026_PF_FP_ABST
Abstract
Description
Carbon dioxide capture device
[0001] This invention relates to a carbon dioxide recovery device.
[0002] Conventionally, in systems that use a heat transfer medium to heat or cool target equipment, the use of heat sources such as heat pumps is a known technique. Patent document 1, for example, describes this type of technique. Patent document 1 relates to an energy-saving ventilation and air conditioning system that maintains an air-conditioned space at a predetermined temperature and humidity.
[0003] Japanese Patent Publication No. 2010-276217
[0004] Incidentally, in carbon dioxide recovery devices that use a module with an adsorbent to draw in a gas such as air containing carbon dioxide, adsorb the carbon dioxide onto the adsorbent, and then heat the adsorbent to desorb the adsorbed carbon dioxide and recover it, heat sources such as heat pumps are also used.
[0005] However, in carbon dioxide capture systems, when carbon dioxide is desorbed, if only a high-temperature heat transfer medium (high-temperature heat transfer medium) heated in a heat source is supplied to the module for heating, there is a problem in that the heating load on the heat source that heats the high-temperature heat transfer medium becomes large. In particular, when the outside temperature is low due to the season being winter, etc., and the temperature of the module before heating is very low (for example, below 5°C), the heating load on the heat source becomes especially large. An increase in the heating load on the heat source increases the power consumption of the heat source, and as a result, the energy consumption of the carbon dioxide capture system increases, which is undesirable.
[0006] The present invention aims to provide a carbon dioxide recovery device that can reduce the heating load on a heat source.
[0007] (1) A carbon dioxide recovery device according to one aspect of the present invention (for example, carbon dioxide recovery device 1 described later) includes an adsorbent (for example, adsorbent 11 described later) inside a module (for example, module 2 described later) which performs an adsorption step of drawing a gas containing carbon dioxide onto the adsorbent to adsorb the carbon dioxide and a desorption step of heating the area around the adsorbent to desorb the carbon dioxide from the adsorbent, a heat pump type heat source (for example, heat source 21 described later) which heats a high-temperature heat transfer medium (for example, high-temperature water described later) and cools a low-temperature heat transfer medium (for example, low-temperature water described later), a high-temperature heat transfer medium tank (for example, high-temperature water tank described later) which stores the high-temperature heat transfer medium heated by the heat source, and a coolant that has been cooled by the heat source The system includes a heat exchange device (for example, a heat exchange device 3, described later) having a low-temperature heat transfer medium tank (for example, a low-temperature water tank 22, described later) for storing the low-temperature heat transfer medium, and a control unit (for example, a control unit 4, described later). The control unit performs a first heating step to raise the temperature of the module by supplying the low-temperature heat transfer medium from the low-temperature heat transfer medium tank to the module when the module is performing the detachment step, and a second heating step to raise the temperature of the module by supplying the high-temperature heat transfer medium from the high-temperature heat transfer medium tank to the module when the temperature of the low-temperature heat transfer medium in the low-temperature heat transfer medium tank is equal to or lower than the temperature of the module.
[0008] In this configuration, when the module performs the desorption process, the module is heated by the low-temperature heat transfer medium as long as the module's temperature is lower than the temperature of the low-temperature heat transfer medium in the low-temperature heat transfer medium tank. This allows the amount of heating of the module by the high-temperature heat transfer medium to be kept to a minimum. Therefore, it is possible to reduce the heating load on the heat source that heats the high-temperature heat transfer medium.
[0009] (2) In the carbon dioxide recovery apparatus described in (1) above, the control unit may perform the first heating step when the module performs the desorption step and the temperature of the low-temperature heat medium in the low-temperature heat medium tank is higher than the minimum temperature required for the operation of the heat source, and perform the second heating step when the temperature of the low-temperature heat medium in the low-temperature heat medium tank is below the minimum temperature.
[0010] In this configuration, a first heating step can be performed in which the module is heated with a low-temperature heat transfer medium so as not to interfere with the operation of the heat source when the module performs the detachment process.
[0011] (3) The carbon dioxide recovery apparatus described in (1) or (2) above further comprises a storage unit (for example, a storage unit 5 described later) that stores an assumed heating profile showing the temporal process of heating the module assumed in advance in the desorption process, and the control unit may continue to perform the first heating process when the module performs the desorption process if the difference between the assumed temperature of the module in the assumed heating profile and the actual measured temperature of the module is less than or equal to a predetermined value, and may perform the second heating process instead of the first heating process if the difference between the assumed temperature of the module and the measured temperature of the module is greater than a predetermined value.
[0012] In this configuration, when the difference between the expected temperature of the module and the measured temperature (temperature difference) becomes large during the first heating process, the control unit switches to a second heating process in which the module is heated with a high-temperature heat transfer medium that is hotter than the low-temperature heat transfer medium. This makes it possible to heat the module efficiently over time while reducing the heating load on the heat source that heats the high-temperature heat transfer medium when the module performs the detachment process.
[0013] (4) The carbon dioxide recovery apparatus described in (1) or (2) above further comprises a storage unit (for example, a storage unit 5 described later) that stores an assumed heating profile showing the temporal process of heating the module assumed in advance in the desorption process, and the control unit continues to perform the first heating process when the module performs the desorption process if the difference obtained by subtracting the actual measured heating rate of the module at the measured temperature from the assumed heating rate of the module in the assumed heating profile at the actual measured temperature of the module is less than or equal to a predetermined value, and if the difference obtained by subtracting the measured heating rate at the measured temperature from the assumed heating rate at the measured temperature is greater than a predetermined value, the control unit may perform the second heating process instead of the first heating process.
[0014] In this configuration, during the first heating step, when the difference between the expected heating rate of the module and the measured heating rate (heating rate difference) at the same temperature (measured temperature) of the module becomes larger than a predetermined value, the control unit switches to a second heating step in which the module is heated with a high-temperature heat transfer medium that is hotter than the low-temperature heat transfer medium. This makes it possible to heat the module efficiently over time while reducing the heating load on the heat source that heats the high-temperature heat transfer medium when the module performs the detachment step.
[0015] According to the present invention, it is possible to reduce the heating load on the heat source that heats the high-temperature heat transfer medium in a carbon dioxide recovery device.
[0016] This is a schematic diagram showing a configuration for heating and cooling a module in a carbon dioxide recovery device according to the first embodiment of the present invention. This is a flowchart showing the temperature rise control of a module in a carbon dioxide recovery device according to the first embodiment of the present invention. This is a graph showing the temperature rise profile of a module corresponding to the flowchart in Figure 2. This is a flowchart showing the temperature rise control of a module in a carbon dioxide recovery device according to the second embodiment of the present invention. This is a graph showing the temperature rise profile of a module corresponding to the flowchart in Figure 4.
[0017] <First Embodiment> Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the following description, corresponding components will be denoted by the same reference numerals, and descriptions of overlapping parts may be omitted.
[0018] Figure 1 is a schematic diagram showing a partial configuration of a carbon dioxide capture device 1 according to the first embodiment. The carbon dioxide capture device 1 is applied, for example, to direct air capture technology (DAC) that captures carbon dioxide from the atmosphere in order to reduce the concentration of carbon dioxide in the atmosphere. The carbon dioxide captured by the carbon dioxide capture device 1 is stored underground or reused as fuel or material.
[0019] As shown in Figure 1, the carbon dioxide recovery device 1 comprises a module 2, a heat exchanger 3, a control unit 4, and a storage unit 5.
[0020] Module 2 is a carbon dioxide recovery module that includes an adsorbent 11 for adsorbing carbon dioxide and a temperature sensor 12 for measuring the temperature of Module 2.
[0021] The adsorbent 11 is placed inside the module 2 to adsorb carbon dioxide. The adsorbent 11 is a particulate material that adsorbs carbon dioxide at low temperatures (for example, in the range of -30°C to 50°C) and desorbs (releases) carbon dioxide at high temperatures (for example, in the range of 50°C to 110°C) and when the ambient carbon dioxide concentration is low. Examples of such an adsorbent 11 include solid amine carbon dioxide adsorbents composed of amines supported on a porous material such as silica.
[0022] The temperature sensor 12 in module 2 measures the temperature of the adsorbent 11. The measurement information from the temperature sensor 12 is transmitted to the control unit 4. Module 2 includes an inlet-side flow path 13 connected to an inlet through which the heat transfer medium flows in, and an outlet-side flow path 14 connected to an outlet through which the heat transfer medium flows out. The heat transfer medium circulates with the heat exchanger 3, which will be described later, to heat and cool module 2.
[0023] The heat exchanger 3 supplies thermal energy to heat the inside of module 2 to a predetermined temperature when module 2 performs the desorption process. The heat exchanger 3 also recovers unnecessary thermal energy when each module 2 performs the adsorption process. The heat exchanger 3 of this embodiment includes a heat source circuit 20, a low-temperature water line 30 (low-temperature heat transfer medium line), a high-temperature water line 40 (high-temperature heat transfer medium line), and a three-way valve 50.
[0024] The heat source circuit 20 includes a heat source 21, a low-temperature water tank 22 (low-temperature heat transfer medium tank), a high-temperature water tank 23 (high-temperature heat transfer medium tank), a heat source low-temperature water line 24 (heat source low-temperature heat transfer medium line), and a heat source high-temperature water line 25 (heat source high-temperature heat transfer medium line).
[0025] The heat source 21 is a heat pump type heat source that cools the low-temperature heat transfer medium (heat transfer medium) and heats the high-temperature heat transfer medium (heat transfer medium). The heat source 21 uses the cooling and heating generated by compressing and expanding gas in the heat pump to cool the low-temperature heat transfer medium flowing between it and the low-temperature water tank 22, and to heat the high-temperature heat transfer medium flowing between it and the high-temperature water tank 23. The heat transfer medium is, for example, a liquid such as water.
[0026] The low-temperature water tank 22 stores the low-temperature heat transfer medium cooled by the heat source 21. The high-temperature water tank 23 stores the high-temperature heat transfer medium heated by the heat source 21. The low-temperature water tank 22 is equipped with a temperature sensor 27. The temperature sensor 27 measures the temperature of the low-temperature heat transfer medium stored in the low-temperature water tank 22. The measurement information from the temperature sensor 27 is transmitted to the control unit 4.
[0027] The heat source low-temperature water line 24 is piping for circulating low-temperature water as a low-temperature heat transfer medium between the low-temperature water tank 22 and the heat source unit 21. Although not shown in the figures, the heat source low-temperature water line 24 is equipped with a circulating water pump for pressurizing the low-temperature water. This circulating water pump can circulate high-temperature water between the high-temperature water tank 23 and the heat source unit 21. This circulating water pump may be, for example, a centrifugal pump.
[0028] The heat source high-temperature water line 25 is piping for circulating high-temperature water as a high-temperature heat transfer medium between the high-temperature water tank 23 and the heat source unit 21. Although not shown in the figures, the heat source high-temperature water line 25 is equipped with a circulating water pump for pressurizing the high-temperature water. This circulating water pump allows the high-temperature water to be circulated between the high-temperature water tank 23 and the heat source unit 21. This circulating water pump may be, for example, a centrifugal pump.
[0029] The cold water line 30 is a pipe through which cold water flows. The cold water line 30 branches and connects to the upstream and downstream sides of module 2, connecting the cold water tank 22 and module 2. Of the cold water line 30, the line connected to the inlet channel 13 located upstream of module 2 is designated as the cold water supply line 31, and the line connected to the outlet channel 14 located downstream of module 2 is designated as the cold water return line 32.
[0030] Although not shown in the diagram, a circulating water pump is located in the low-temperature water supply line 31. This circulating water pump flows low-temperature water from the low-temperature water tank 22 towards module 2. For example, a cascade pump is used for this circulating water pump.
[0031] The high-temperature water line 40 is a pipe through which high-temperature water flows. The high-temperature water line 40 branches and connects to the upstream and downstream sides of module 2, connecting the high-temperature water tank 23 and module 2. Of the high-temperature water line 40, the line connected to the inlet channel 13 located upstream of module 2 is designated as the high-temperature water supply line 41, and the line connected to the outlet channel 14 located downstream of module 2 is designated as the high-temperature water return line 42.
[0032] Although not shown in the diagram, a circulating water pump, for example, is located in the high-temperature water supply line 41. This circulating water pump flows high-temperature water from the high-temperature water tank 23 towards module 2. For example, a cascade pump is used for this circulating water pump. By using a cascade pump, which generates a large amount of heat when driven, the high-temperature water (heat transfer medium) passing through the circulating water pump can be further heated.
[0033] The three-way valve 50 is connected to the low-temperature water line 30, the high-temperature water line 40, and the module 2. The three-way valve 50 is positioned on both the upstream and downstream sides of the module 2. The three-way valve 50 is configured to allow selection by flow path switching between a low-temperature water connection state, where the module 2 is connected only to the low-temperature water line 30; a high-temperature water connection state, where the module 2 is connected only to the high-temperature water line 40; and a disconnection state, where the connection between the low-temperature water line 30 and the high-temperature water line 40 and the module 2 is cut off.
[0034] The flow path switching of the three-way valve 50 is controlled by the control unit 4. A heat transfer medium is introduced into module 2 through the three-way valve 50 located on the upstream side, and the heat transfer medium is returned from module 2 to the heat source 21 side through the three-way valve 50 located on the downstream side. In the following description, the three-way valve 50 located on the upstream side of module 2 will be referred to as three-way valve 50a, and the three-way valve 50 located on the downstream side of module 2 will be referred to as three-way valve 50b.
[0035] A three-way valve 50a is positioned at the upstream end of the inlet-side flow path 13, and a three-way valve 50b is also positioned at the downstream end of the outlet-side flow path 14. When high-temperature water is connected, the three-way valve 50a is connected to the high-temperature water supply line 41, and the three-way valve 50b is connected to the high-temperature water return line 42. When low-temperature water is connected, the three-way valve 50a is connected to the low-temperature water supply line 31, and the three-way valve 50b is connected to the low-temperature water return line 32.
[0036] The three-way valves 50a and 50b are configured to allow for flow rate adjustment. This flow rate adjustment function allows for adjustment of the flow rate of high-temperature water when connected to high-temperature water, and adjustment of the flow rate of low-temperature water when connected to low-temperature water.
[0037] The control unit 4 controls the operation of each part of the carbon dioxide capture device 1. The control unit 4 controls the operation of devices used for carbon dioxide adsorption and desorption in module 2, such as driving and stopping. The control unit 4 selectively controls the timing of supplying a heat transfer medium to module 2 to provide heating and cooling, so that module 2 can repeatedly perform adsorption and desorption in a time series.
[0038] Devices controlled by the control unit 4 include the aforementioned heat source 21, three-way valve 50, and circulating water pump (not shown). Although not shown, devices controlled by the control unit 4 also include valves for opening and closing piping to introduce and discharge gases such as air to and from module 2, a flow fan for circulating gases such as air through piping in module 2, a vacuum pump for reducing the pressure inside module 2 to desorb carbon dioxide from the adsorbent 11, valves for opening and closing piping to discharge and recover carbon dioxide from module 2, a recovery pump for recovering carbon dioxide discharged from module 2, and a desorbed water condenser (intercooler) for separating water discharged along with carbon dioxide from carbon dioxide.
[0039] The control unit 4 is, for example, a computer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The control unit 4 may consist of one unit or multiple units. The control unit 4 may also be configured using electrical circuits such as relays.
[0040] In the carbon dioxide recovery device 1, the cold water stored in the cold water tank 22 is supplied to module 2 (adsorbent 11). The cold water stored in the cold water tank 22 is also supplied to various auxiliary equipment that generates heat when in operation, such as the vacuum pump, desorbed water condenser, water pump, circulation fan, and recovery pump, and is used to cool these auxiliary equipment.
[0041] The memory unit 5 stores the assumed temperature rise profile illustrated in Figure 3. The assumed temperature rise profile shows the pre-determined time course of the temperature rise of module 2 in the desorption process in which carbon dioxide adsorbed on the adsorbent 11 is desorbed. Details of the assumed temperature rise profile will be described later.
[0042] <Carbon Dioxide Recovery> Next, the control by the control unit 4 for carbon dioxide recovery will be explained. The carbon dioxide recovery device 1 alternately performs an adsorption process in which gas such as air is drawn into the adsorbent material 11 in the module 2 and carbon dioxide in the gas is adsorbed, and a desorption process in which carbon dioxide adsorbed on the adsorbent material 11 is desorbed. The desorbed carbon dioxide is stored in a carbon dioxide tank (not shown), thereby removing and recovering carbon dioxide from the air.
[0043] The adsorption process involves adsorbing carbon dioxide onto the adsorbent material 11 within module 2. During the adsorption process, the control unit 4 controls the three-way valves 50a and 50b of the heat exchanger 3 to a low-temperature water connection state, and low-temperature water flows through module 2 to cool the adsorbent material 11 within module 2. The control unit 4 operates a circulation fan (not shown) to draw in a gas containing carbon dioxide (for example, air). The drawn-in gas passes through the adsorbent material 11 within module 2. At this time, the temperature inside the cooled module 2 is, for example, the same as the ambient temperature, and the carbon dioxide in the drawn-in gas is adsorbed onto the adsorbent material 11. Gases other than carbon dioxide, such as nitrogen and oxygen, are exhausted to the outside of the carbon dioxide recovery device 1.
[0044] The desorption process is a process of desorbing carbon dioxide from the adsorbent 11 in module 2. In the desorption process, the control unit 4 operates a vacuum pump (not shown) to draw air into the inside of module 2, reducing the pressure to a vacuum state or close to a vacuum state. The control unit 4 also appropriately controls the operation of the three-way valves 50a and 50b of the heat exchanger 3, so that the heat transfer medium of the heat exchanger 3 flows through module 2 and supplies thermal energy, raising the temperature of the adsorbent 11 in module 2. Through the temperature rise control of the adsorbent 11 by the control unit 4, the adsorbent 11 is heated to a predetermined temperature (for example, 80°C) sufficient for the desorption process, and the carbon dioxide adsorbed on the adsorbent 11 is desorbed. Detailed temperature rise control of the adsorbent 11 in the desorption process will be described later with reference to Figures 2 and 3. Furthermore, during the desorption process, the control unit 4 opens a valve in the piping for recovering carbon dioxide, and the recovery pump for recovering carbon dioxide is activated, so that the carbon dioxide desorbed in module 2 is stored in a carbon dioxide tank (not shown).
[0045] Next, with reference to Figures 2 and 3, a detailed explanation of the temperature rise control of module 2 performed by the control unit 4 during the desorption process will be given. Figure 2 is a flowchart showing the temperature rise control of module 2 performed by the control unit 4 during the desorption process. Figure 3 is a graph showing the temperature rise profile of module 2.
[0046] As shown in Figure 2, the control unit 4 selectively performs a first heating step (step S13) in which low-temperature water is supplied from the low-temperature water tank 22 to the module 2, and a second heating step (step S15) in which high-temperature water is supplied from the high-temperature water tank 23 to the module 2 during the desorption process. In most cases, the control unit 4 performs the first heating step and the second heating step in order. The heating control of module 2 will be described in detail below, mainly following the flowchart in Figure 2.
[0047] When the detachment process is initiated, the control unit 4 first checks the temperature T of the cold water in the cold water tank 22, which was measured by the temperature sensor 27 in step S11. ＬＴ However, the actual temperature T of module 2 measured by temperature sensor 12 ＭＭ (Hereinafter, measured temperature T ＭＭreferred to as ). The control unit 4 determines whether or not the temperature T of low-temperature water is higher than that. ＬＴ is the measured temperature T of the module 2 ＭＭ If it is determined to be higher than that, the process proceeds to step S12 described later. On the other hand, the control unit 4 determines that the temperature T of low-temperature water ＬＴ is the measured temperature T of the module 2 ＭＭ If it is determined to be equal to or lower than that, the process proceeds to step S15 to execute the second temperature increasing step. The second temperature increasing step is performed until the temperature of the module 2 (measured temperature T ＭＭ ) reaches the target temperature in the desorption step (temperature T shown in FIG. 3 ＴＤ ), the step is continuously performed.
[0048] When the control unit 4 executes step S11, the temperature T of low-temperature water in the low-temperature water tank 22 ＬＴ is the measured temperature T of the module 2 ＭＭ When the temperature is higher than that, the module 2 can be heated by the low-temperature water supplied from the low-temperature water tank 22 to the module 2. On the other hand, the temperature T of low-temperature water in the low-temperature water tank 22 ＬＴ is the measured temperature T of the module 2 ＭＭ When the temperature is equal to or lower than that, the module 2 cannot be heated by low-temperature water, but the module 2 can be heated by high-temperature water supplied from the high-temperature water tank 23 to the module 2.
[0049] When the process proceeds to step S12, the control unit 4 determines, in step S12, the temperature T of low-temperature water in the low-temperature water tank 22 measured by the temperature sensor 27 ＬＴ is the minimum temperature T required for the operation of the heat source device 21 ＬＴ０ It is determined whether or not the temperature is higher than that. Here, the "minimum temperature T ＬＴ０ " is the minimum temperature of low-temperature water in the low-temperature water tank 22 required for the operation of the heat source device 21, and is, for example, the minimum temperature of low-temperature water required for causing high-temperature water in the high-temperature water tank 23 to reach a target temperature. Then, the control unit 4 determines that the temperature T of low-temperature water ＬＴ is the minimum temperature T ＬＴ０ If it is determined to be higher than that, the process proceeds to step S13 to execute the first temperature increasing step. On the other hand, the control unit 4 determines that the temperature T of low-temperature water ＬＴ is the minimum temperature T ＬＴ０If the following is determined, proceed to step S15 and perform the second heating process.
[0050] The control unit 4 performs step S12, thereby controlling the temperature T of the cold water in the cold water tank 22. ＬＴ is the lowest temperature T ＬＴ０ If the temperature is higher than the specified temperature, supplying cold water from the cold water tank 22 to the module 2 can suppress or prevent the operation of the heat source 21 from being disrupted due to the temperature of the cold water, even if the temperature of the cold water in the cold water tank 22 decreases.
[0051] After step S13, the process proceeds to step S14 with the first heating step being performed. In step S14, the control unit 4 determines the assumed temperature T of module 2 in the assumed heating profile (see Figure 3) stored in the storage unit 5. ＴＰ From Module 2, the actual measured temperature T ＭＭ It is determined whether the difference after subtracting is less than or equal to a predetermined value X°C. The predetermined value X°C can be any value, but for example it may be 7°C.
[0052] Here, with reference to Figure 3, the heating profile of module 2 in the desorption process will be explained. In the graph of Figure 3, the heating profile shows the temporal change in the temperature of module 2 when it is heated in the desorption process. In the graph of Figure 3, time t0 corresponds to the start time of the desorption process (i.e., heating of module 2), and the time before time t0 (left side of the graph) corresponds to the adsorption process. The temperature of module 2 before time t0 T Ａ This is a relatively low temperature (e.g., 5°C) suitable for carbon dioxide adsorption. Time t5 corresponds to the end time of the desorption process, and the time after time t5 (to the right in the graph) corresponds to the cooling process for cooling module 2. After this cooling process, the adsorption process, desorption process, and cooling process are carried out in order.
[0053] Temperature T in the graph of Figure 3 ＬＴ T is the temperature of the cold water in the cold water tank 22. ＬＴ This refers to the temperature T of module 2 in the adsorption process.Ａ It is higher than that, for example, 30°C. Also, temperature T in the graph of Figure 3 ＴＤ This is the target temperature of module 2 in the desorption process. Target temperature T of module 2 ＴＤ The temperature T of the cold water in the cold water tank 22 is... ＬＴ It is considerably higher than that, for example, 80°C.
[0054] Figure 3 shows the assumed temperature rise profile, the actual temperature rise profile, and the temperature rise profile of the comparative example.
[0055] The assumed heating profile is an example of a target heating profile that assumes good efficiency in heating module 2 when the first heating process and the second heating process are performed in sequence. In the assumed heating profile, the first heating process is performed for a predetermined time starting from time t0, and then the second heating process is performed for another predetermined time.
[0056] In the assumed heating profile in which the first heating process and the second heating process are performed in sequence, as time progresses from time t0, and the temperature of the low-temperature water in the low-temperature water tank 22 T ＬＴ As the temperature approaches the target temperature T of module 2, the rate of temperature increase over time decreases, and the rate of temperature increase of module 2 increases discontinuously when switching from the first heating process to the second heating process. Furthermore, after switching to the second heating process, as time progresses, the target temperature T of module 2 in the desorption process also increases. ＴＤ As we approach the target temperature T, the rate of temperature rise of module 2 decreases again, but the temperature of module 2 is ＴＤ It reaches.
[0057] The actual heating profile is an example of a heating profile when the first and second heating processes are actually carried out in order according to the flowchart shown in Figure 2. The trend of temperature rise in module 2 in the actual heating profile is the same as that of the assumed heating profile. However, in the actual heating profile, the rate of temperature rise over time (heating rate) of module 2 in the first heating process is lower than that of the assumed heating profile.
[0058] The comparative example's heating profile is an example of a heating profile when the second heating step is performed. In the comparative example's heating profile, module 2 is heated using only the high-temperature water in the high-temperature water tank 23, so the rate of temperature rise (heating rate) of module 2 is higher compared to the assumed heating profile and the actual heating profile described above. However, in the comparative example's heating profile, module 2 is heated using only the high-temperature water in the high-temperature water tank 23, so the heating load on the heat source 21 that heats the high-temperature water is large, and the power consumption of the heat source 21 increases. As a result, the energy consumption of the carbon dioxide recovery device 1 increases.
[0059] As shown in Figure 2, in step S14, the control unit 4 sets the assumed temperature T of module 2 in the assumed temperature rise profile. ＴＰ From Module 2, the actual measured temperature T ＭＭ If the difference after subtracting is determined to be less than or equal to a predetermined value X°C, the first heating process continues and the system returns to step S11. Meanwhile, the control unit 4 determines the assumed temperature T of module 2 in the assumed heating profile. ＴＰ From Module 2, the actual measured temperature T ＭＭ If the difference after subtracting is determined to be greater than a predetermined value X°C, the process proceeds to step S15 to perform the second heating step. Assumed temperature T in step S14 ＴＰ and measured temperature T ＭＭ The difference is the assumed temperature T at the same time after a predetermined elapsed from the start time of the desorption process (time t0 in Figure 3). ＴＰ and measured temperature T ＭＭ This is the difference.
[0060] In Figure 3, the assumed temperature T of module 2 in the assumed heating profile is shown. ＴＰ From the actual heating profile, the measured temperature T ＭＭ The difference (temperature difference) after subtracting the above increases over time. Figure 3 shows the assumed temperature T of module 2. ＴＰ From Module 2, the measured temperature T ＭＭ As an example of the temperature difference after subtracting a predetermined value X°C, X is less than or equal to X°C. ０ °C and X greater than a given value X °C. １°C and are shown. And a small temperature difference X ０ After time t1, when the temperature reaches a predetermined value X°C or less, X １ There exists a time t2 at which the temperature is greater than a predetermined value X°C. In the actual heating profile shown in Figure 3, the assumed temperature T of module 2 is... ＴＰ From the measured temperature T ＭＭ The temperature difference after subtracting X is ０ If the temperature is °C, the first heating process is continued, and the temperature difference is X １ The diagram shows the process of switching from the first heating step to the second heating step when the temperature is in °C.
[0061] As described above, in the carbon dioxide recovery device 1 according to the first embodiment, when the module 2 performs the desorption process, the control unit 4 selectively performs a first heating step of supplying low-temperature water from the low-temperature water tank 22 to the module 2 and a second heating step of supplying high-temperature water from the high-temperature water tank 23 to the module 2. The control unit 4 then controls the temperature T of the low-temperature water in the low-temperature water tank 22. ＬＴ The temperature T of module 2 ＭＭ (Measurement temperature T ＭＭ If the temperature is higher than ), the first heating step is performed, and the temperature of the cold water in the cold water tank 22 is T ＬＴ The measurement temperature T of module 2 ＭＭ The second heating step is performed when the following conditions are met. For this reason, when module 2 performs the desorption step, the measured temperature T of module 2 ＭＭ The temperature of the cold water in the cold water tank 22 is T ＬＴ While the temperature is lower than this, module 2 is heated by the low-temperature water. This allows the amount of heating of module 2 by the high-temperature water to be kept to a minimum. Therefore, it is possible to reduce the heating load on the heat source 21 that heats the high-temperature water.
[0062] Heating module 2 with the cold water in the cold water tank 22 is particularly useful when the outside temperature is low (for example, 5°C), such as in winter. When the outside temperature is low, the temperature T of the cold water in the cold water tank 22 depends on the operating conditions of the heat source 21. ＬＴ The temperature is higher than the ambient temperature, and the measurement temperature T of module 2 in the adsorption process is also higher. ＭＭThe temperature becomes approximately equal to the ambient temperature. Therefore, it becomes possible to sufficiently heat module 2 with the low-temperature water in the low-temperature water tank 22.
[0063] Furthermore, in the carbon dioxide recovery device 1 according to the first embodiment, when module 2 performs the desorption process, control unit 4 controls the temperature T of the cold water in the cold water tank 22. ＬＴ The minimum temperature T required for the operation of the heat source 21 ＬＴ０ If the temperature is higher than T, the first heating step is performed, and the temperature of the low-temperature water in the low-temperature water tank 22 is increased. ＬＴ is the lowest temperature T ＬＴ０ The second heating step is performed in the following cases. This allows the first heating step, in which module 2 is heated with a low-temperature heat transfer medium, to be performed without interfering with the operation of the heat source 21.
[0064] Temperature T of the cold water in the cold water tank 22 ＬＴ is the lowest temperature T ＬＴ０ Performing the first heating step (supplying cold water from the cold water tank 22 to module 2) only when the temperature is higher than a certain threshold is particularly useful when the outside temperature is low (e.g., 5°C), such as in winter. This point will be explained below. When the outside temperature is high, such as in summer, the amount of heat dissipated into the outside air from the various auxiliary equipment is small, so much of the heat discharged from module 2 and the various auxiliary equipment (waste heat) is recovered by the cold water supplied from the cold water tank 22. For this reason, the temperature of the cold water in the cold water tank 22 is low. ＬＴ The temperature becomes relatively high. Therefore, the temperature T of the cold water in the cold water tank 22 ＬＴ The minimum temperature T is maintained by the heat dissipated from module 2 and various auxiliary components. ＬＴ０ It is often significantly higher than that.
[0065] On the other hand, when the outside temperature is low, such as in winter, a large amount of heat is dissipated into the outside air from the various auxiliary components. Therefore, the amount of heat recovered by the low-temperature water supplied from the low-temperature water tank 22 from the heat discharged from module 2 and the various auxiliary components (waste heat) is small. For this reason, the temperature T of the low-temperature water in the low-temperature water tank 22 is small. ＬＴ The temperature becomes relatively low. As a result, the temperature T of the cold water in the cold water tank 22 ＬＴ However, the lowest temperature T ＬＴ０It is highly likely that the temperature will be close to this. Therefore, the temperature of the cold water in the cold water tank 22 is T ＬＴ is the lowest temperature T ＬＴ０ Performing the first heating step only when the temperature is higher than a certain level is particularly useful when the ambient temperature is low.
[0066] Furthermore, in the carbon dioxide recovery device 1 according to the first embodiment, the storage unit 5 stores a hypothetical temperature rise profile that shows the time process of the module 2's temperature rise in the desorption process, which is assumed in advance. When the module 2 performs the desorption process, the control unit 4 sets the assumed temperature T of the module 2 in the hypothetical temperature rise profile. ＴＰ From Module 2, the actual measured temperature T ＭＭ If the difference after subtracting is less than or equal to a predetermined value X°C, the first heating process is continued, and the assumed temperature T of module 2 is reached. ＴＰ Therefore, the measurement temperature T of module 2 ＭＭ If the difference after subtracting is greater than a predetermined value X°C, the second heating step is performed instead of the first heating step. In the first heating step, the assumed temperature T of module 2 is performed. ＴＰ From the measured temperature T ＭＭ A larger difference (temperature difference) after subtracting the low temperature means that the heating efficiency of module 2 by low temperature water decreases. In contrast, in the above method by the control unit 4, when the above temperature difference in the first heating step becomes larger than a predetermined value X°C, the control unit 4 switches to a second heating step in which module 2 is heated with high temperature water, which is hotter than the low temperature water. This makes it possible to heat module 2 efficiently in terms of time while reducing the heating load on the heat source 21 that heats the high temperature water when module 2 performs the detachment step.
[0067] In the first embodiment, the control unit 4 performed the three steps S11, S12, and S14 shown in Figure 2 when the module 2 performed the detachment process, but it is sufficient to perform at least the step S11. For example, the control unit 4 may perform only the steps S11 and S12, or only the steps S11 and S14.
[0068] <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. A carbon dioxide capture device 1 according to the second embodiment is the same as the carbon dioxide capture device 1 of the first embodiment shown in FIG. 1. The second embodiment differs from the first embodiment only in the control performed by the control unit 4 when heating the module 2 in the desorption step. In the following description, configurations corresponding to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0069] As shown in FIG. 4, in the second embodiment, the control unit 4 performs steps S11, S12, S13, and S15 similar to those in the first embodiment. However, in the second embodiment, after step S13, the process proceeds to step S16 while the first temperature raising step is being performed.
[0070] As shown in FIGS. 4 and 5, in step S16, the control unit 4 controls the actual measured temperature T of the module 2 ＭＭ the estimated temperature increase rate (dT ＭＭ / dt) of the module 2 in an estimated temperature increase profile (see FIG. 5) ＴＰ at the actual measured temperature T ＭＭ whether the difference obtained by subtracting the actual measured temperature increase rate (dT ＭＭ / dt) ＭＭ of the module 2 at the same temperature is less than or equal to a predetermined value Y°C / sec. The predetermined value Y°C / sec may be any arbitrary value, and may be, for example, 0.02°C / sec.
[0071] In step S16, the control unit 4 determines, based on the estimated temperature increase rate (dT ＭＭ / dt) at the measured temperature T ＭＭ of the module 2 ＴＰ , if the difference (temperature increase rate difference) obtained by subtracting the measured temperature increase rate (dT ＭＭ / dt) ＭＭ of the module 2 at the measured temperature T ＭＭ is less than or equal to the predetermined value Y°C / sec, the process returns to step S11 while continuing the first temperature raising step. On the other hand, the control unit 4 ＭＭ / dt) ＴＰ to the measured temperature increase rate (dT ＭＭ / dt) ＭＭIf it is determined that the difference in heating rate after subtracting is greater than a predetermined value Y°C / sec, the process proceeds to step S15, and the second heating process is performed instead of the first heating process.
[0072] As shown in Figure 5, in the actual heating profile, the rate of temperature increase over time of module 2 in the first heating step is lower than in the assumed heating profile. Therefore, in the first heating step, the same temperature (measured temperature T) ＭＭ ) Measurement heating rate (dT ＭＭ ( / dt) ＭＭ However, the expected heating rate (dT ＭＭ ( / dt) ＴＰ It is smaller than that. Also, the assumed heating rate (dT) at the same temperature ＭＭ ( / dt) ＴＰ The measured heating rate (dT) ＭＭ ( / dt) ＭＭ The difference in heating rate after subtracting the above increases with time in the actual heating profile. In this way, by appropriately setting the predetermined value Y°C / sec mentioned above, when a predetermined time has elapsed from the start time of the desorption process (time t0), the process of heating module 2 in the desorption process is switched from the first heating process to the second heating process.
[0073] The second embodiment provides the same effects as the first embodiment. In the second embodiment, as in the first embodiment, the memory unit 5 stores a hypothetical temperature rise profile that shows the time process of the module 2's temperature rise, which is assumed in advance during the detachment process. When the module 2 performs the detachment process, the control unit 4 sets the actual measured temperature T of the module 2. ＭＭ The assumed heating rate (dT) of module 2 in the assumed heating profile. ＭＭ ( / dt) ＴＰ Therefore, the actual measured temperature T of module 2 ＭＭ Actual measured heating rate (dT) of module 2 in ＭＭ ( / dt) ＭＭ If the difference after subtracting is less than or equal to a predetermined value Y°C / sec, the first heating process is continued. Meanwhile, the actual measured temperature T of module 2 ＭＭ The assumed heating rate (dT) of module 2 in ＭＭ ( / dt)ＴＰ The measured heating rate (dT) ＭＭ ( / dt) ＭＭ If the difference after subtracting the specified value is greater than a predetermined value Y°C / sec, the second heating step is performed instead of the first heating step.
[0074] In the first heating step, the predetermined temperature of module 2 (measured temperature T) ＭＭ ) The assumed heating rate (dT) of module 2 ＭＭ ( / dt) ＴＰ The measured heating rate (dT) ＭＭ ( / dt) ＭＭ A larger difference in heating rate after subtracting the difference means that the heating efficiency of module 2 using low-temperature water decreases. In contrast, in the above method by the control unit 4, when the difference in heating rate in the first heating step becomes larger than a predetermined value Y°C / sec, the control unit 4 switches to a second heating step in which module 2 is heated with high-temperature water, which is hotter than the low-temperature water. This makes it possible to heat module 2 efficiently in terms of time while reducing the heating load on the heat source 21 that heats the high-temperature water when module 2 performs the desorption step.
[0075] In the second embodiment, the control unit 4 performed the three steps S11, S12, and S16 shown in Figure 4 when the module 2 performed the detachment process, but it is sufficient to perform at least the step S11. For example, the control unit 4 may perform only the steps S11 and S12, or only the steps S11 and S16.
[0076] Although embodiments of the present invention have been described above, the invention is not limited to the embodiments and modifications described above. Furthermore, the effects described in the above embodiments are merely a list of preferred effects and are not limited to those described in the above embodiments.
[0077] For example, the carbon dioxide capture device 1 may include multiple modules 2. In this case, for example, the low-temperature water line 30 and the high-temperature water line 40 may be branched and configured to be connected in parallel to the multiple modules 2.
[0078] The present invention is not limited to being applied to carbon dioxide recovery devices, but may also be applied to gas recovery devices that recover a specific gas (specific gas) contained in any gas (mixed gas). In this case, the adsorbent placed in the module to adsorb the specific gas only needs to have the property of adsorbing the specific gas at low temperatures and desorbing (releasing) the specific gas at high temperatures and when the concentration of the specific gas in the surrounding environment is low.
[0079] 1...Carbon dioxide capture device 2...Module 3...Heat exchange device 4...Control unit 5...Memory unit 11...Adsorbent 21...Heat source 22...Low temperature water tank (low temperature heat transfer tank) 23...High temperature water tank (high temperature heat transfer tank) T ＬＴ ...Temperature T of the cold water in the cold water tank 22 ＬＴ０ ...Minimum temperature required for operation of heat source 21 T ＭＭ ...Measurement temperature T of module 2 ＴＰ ...Assumed temperature of module 2 (dT ＭＭ ( / dt) ＭＭ ...Measured heating rate (dT) ＭＭ ( / dt) ＴＰ ...Expected heating rate
Claims
1. A module having an adsorbent inside, which performs an adsorption step of drawing a gas containing carbon dioxide onto the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the area around the adsorbent to desorb the carbon dioxide from the adsorbent; a heat exchange device having a heat pump type heat source for heating a high-temperature heat transfer medium and cooling a low-temperature heat transfer medium, a high-temperature heat transfer medium tank for storing the high-temperature heat transfer medium heated by the heat source, and a low-temperature heat transfer medium tank for storing the low-temperature heat transfer medium cooled by the heat source; and a control unit, wherein when the module performs the desorption step, the control unit performs a first heating step of supplying the low-temperature heat transfer medium from the low-temperature heat transfer medium tank to the module to raise the module temperature if the temperature of the low-temperature heat transfer medium in the low-temperature heat transfer medium tank is higher than the temperature of the module, and performs a second heating step of supplying the high-temperature heat transfer medium from the high-temperature heat transfer medium tank to the module to raise the module temperature if the temperature of the low-temperature heat transfer medium in the low-temperature heat transfer medium tank is lower than or equal to the temperature of the module. Carbon dioxide capture device.
2. The carbon dioxide recovery apparatus according to claim 1, wherein the control unit, when the module performs the desorption step, performs the first heating step when the temperature of the low-temperature heat medium in the low-temperature heat medium tank is higher than the minimum temperature required for the operation of the heat source, and performs the second heating step when the temperature of the low-temperature heat medium in the low-temperature heat medium tank is below the minimum temperature.
3. The carbon dioxide recovery apparatus according to claim 1 or 2, further comprising a storage unit that stores an assumed heating profile showing the temporal process of heating the module assumed in advance in the desorption step, wherein the control unit, when the module performs the desorption step, continues to perform the first heating step if the difference between the assumed temperature of the module in the assumed heating profile and the actual measured temperature of the module is less than or equal to a predetermined value, and performs the second heating step instead of the first heating step if the difference between the assumed temperature of the module and the measured temperature of the module is greater than a predetermined value.
4. The carbon dioxide recovery apparatus according to claim 1 or 2, further comprising a storage unit that stores an assumed heating profile showing the temporal process of heating the module assumed in advance in the desorption step, wherein the control unit, when the module performs the desorption step, continues to perform the first heating step if the difference between the assumed heating rate of the module in the assumed heating profile at the actual measured temperature of the module and the actual measured heating rate of the module at the measured temperature is less than or equal to a predetermined value, and performs the second heating step instead of the first heating step if the difference between the assumed heating rate at the measured temperature and the measured heating rate at the measured temperature is greater than a predetermined value.