Method for recovering carbon dioxide contained in exhaust gas

Abstract

To provide a CO2 recovery method capable of sufficiently raising the temperature of an adsorbent in a shorter time in a desorbing process.SOLUTION: The method for recovering carbon dioxide includes a preliminary cooling step of cooling an adsorbent in an adsorption tower by using a heat medium, an adsorption step of supplying exhaust gas to the adsorption tower and adsorbing carbon dioxide by the adsorbent, a preliminary heating step of heating the adsorbent by using the heat medium, and a desorption step of desorbing carbon dioxide from the adsorbent, wherein the preliminary cooling step is performed after the desorption step, the adsorption step is performed after the preliminary cooling step, the preliminary heating step is performed after the adsorption step, and the desorption step is performed after the preliminary heating step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for recovering carbon dioxide contained in exhaust gas. [Background technology]

[0002] Patent Document 1 discloses a method for recovering carbon dioxide from exhaust gas using an adsorbent whose adsorption amount of carbon dioxide changes depending on temperature. Specifically, the adsorbent is cooled in an adsorption step in which carbon dioxide is adsorbed onto the adsorbent, and is heated in a desorption step in which carbon dioxide is desorbed from the adsorbent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-069417 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method disclosed in Patent Document 1, the rate of temperature rise of the adsorbent in the desorption step is slow, and the temperature does not rise sufficiently, so there is a risk that the amount of carbon dioxide that can be recovered will decrease. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] According to one aspect of the present disclosure, there is provided a method for recovering carbon dioxide contained in exhaust gas, the method comprising: a pre-cooling step of cooling an adsorbent in an adsorption tower using a heat medium; an adsorption step of supplying the exhaust gas to the adsorption tower and causing the adsorbent to adsorb the carbon dioxide; a pre-heating step of heating the adsorbent using a heat medium; and a desorption step of desorbing the carbon dioxide from the adsorbent and recovering the carbon dioxide from the adsorption tower, wherein the pre-cooling step is performed after the desorption step, the adsorption step is performed after the pre-cooling step, the pre-heating step is performed after the adsorption step, and the desorption step is performed after the pre-heating step, and the pre-cooling step includes discharging the heat medium used in the desorption step from the adsorption tower to a high-temperature heat medium tank; the adsorption step includes supplying the heat medium used in the adsorption step to the adsorption tower, etc., to cool the adsorbent, and the adsorption step includes supplying a cooled heat medium from a low-temperature heat medium tank to the adsorption tower and cooling the adsorbent using the heat medium; the preheating step includes discharging the heat medium used in the adsorption step from the adsorption tower to the low-temperature heat medium tank, and supplying the heat medium kept warm in an insulated container to the adsorption tower to heat the adsorbent; and the desorption step includes supplying a heated heat medium from the high-temperature heat medium tank to the adsorption tower, heating the adsorbent using the heat medium, and supplying the heat medium from the adsorption tower to the insulated container. In this method for recovering carbon dioxide, the preheating step includes discharging the oil used in the adsorption step from the adsorption tower to the low-temperature heat medium tank, and supplying high-temperature oil kept warm in the heat-insulating container to the adsorption tower to heat the adsorbent. This allows the heat of the high-temperature oil kept warm in the heat-insulating container to be transferred more efficiently to the adsorbent. This allows the desorption step to be performed with the adsorbent temperature elevated, preventing a decrease in the amount of carbon dioxide that can be recovered. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an explanatory diagram showing the configuration of a carbon dioxide capture system according to an embodiment of the present disclosure and steps of a method for capturing carbon dioxide contained in exhaust gas. [Figure 2] This is a diagram for explaining an example of the operation of a CO2 recovery system that executes a CO2 recovery method. [Figure 3] This is a graph showing the temperature change of the adsorbent.

Embodiments for Carrying Out the Invention

[0008] A. Embodiment: FIG. 1 is an explanatory diagram showing the configuration of a carbon dioxide recovery system (hereinafter referred to as a CO2 recovery system) 1 as an embodiment of the present disclosure, and the steps of a method for recovering carbon dioxide contained in exhaust gas (hereinafter also referred to as a CO2 recovery method). The CO2 recovery system 1 and the CO2 recovery method are used to recover CO2 contained in exhaust gas from factories and the like. More specifically, by using adsorbents AD1, AD2, AD3, and AD4 whose saturated adsorption amount of CO2 changes depending on temperature, and adjusting the temperature of the adsorbents AD1 to AD4, the adsorption and recovery of CO2 are performed.

[0009] <Configuration of the CO2 recovery system 1> As shown in FIG. 1, the CO2 recovery system 1 includes four adsorption towers 100, 200, 300, and 400, a low-temperature heat medium tank 500, a high-temperature heat medium tank 600, and a heat-insulating container 700. In FIG. 1, for the sake of illustration, a part of the flow path and the valve are omitted. In reality, the four adsorption towers 100 to 400 and the flow paths and valves connected to them all have a symmetric configuration.

[0010] <Configuration of the adsorption towers 100 to 400> The adsorption towers 100 to 400 are barrel-shaped containers for reacting exhaust gas with the adsorbents AD1 to AD4. The adsorption towers 100 to 400 include the adsorbents AD1 to AD4, gas supply ports IN1, IN2, IN3, IN4, gas chambers GR1, GR2, GR3, GR4, gas discharge ports OUT1, OUT2, OUT3, OUT4, and oil chambers OR1, OR2, OR3, OR4.

[0011] The adsorbents AD1 to AD4 are materials whose saturated adsorption amount of CO2 changes depending on the temperature. The adsorbents AD1 to AD4 are, for example, zeolites. The adsorbents AD1 to AD4 in the present disclosure have the property that the saturated adsorption amount of CO2 increases as the temperature decreases and decreases as the temperature increases. The adsorbents AD1 to AD4 are arranged along the axial direction of the adsorption towers 100 to 400.

[0012] Gas supply ports IN1 to IN4 are provided at one end of the adsorption towers 100 to 400. Exhaust gas is supplied into the adsorption towers 100 to 400 through the gas supply ports IN1 to IN4. CO2 recovered from the exhaust gas is discharged from the adsorption towers 100 to 400 through the gas supply ports IN1 to IN4. Valves Vin1, Vin2, Vin3, and Vin4 are provided at the gas supply ports IN1 to IN4. The valves Vin1 to Vin4 open and close the gas supply ports IN1 to IN4.

[0013] The gas outlets OUT1 to OUT4 are provided at the other ends of the adsorption towers 100 to 400. The exhaust gas from which CO2 has been removed by the adsorbents AD1 to AD4 is discharged from the adsorption towers 100 to 400 via the gas outlets OUT1 to OUT4. In addition, a purge gas used to discharge CO2 recovered from the exhaust gas from the adsorption towers 100 to 400 is supplied to the adsorption towers 100 to 400 via the gas outlets OUT1 to OUT4. Valves Vout1, Vout2, Vout3, and Vout4 are provided at the gas outlets OUT1 to OUT4. The valves Vout1 to Vout4 open and close the gas outlets OUT1 to OUT4.

[0014] The oil chambers OR1 to OR4 are spaces to which a heat medium is supplied to adjust the temperature of the adsorbents AD1 to AD4. In the present disclosure, the heat medium is oil. The oil chambers OR1 to OR4 are arranged so as to sandwich the adsorbents AD1 to AD4.

[0015] <Configuration of low-temperature heat medium tank 500> The low-temperature heat transfer medium tank 500 is a container that stores relatively low-temperature oil. In the present disclosure, the oil in the low-temperature heat transfer medium tank 500 is adjusted to 20°C by a cooler CL.

[0016] <Configuration of high-temperature heat medium tank 600> The high-temperature heat medium tank 600 is a container for storing relatively high-temperature oil. In the present disclosure, the oil in the high-temperature heat medium tank 600 is pumped up by a first pump P1, heated by a heater HT, and then supplied to the adsorption towers 100-400.

[0017] <Configuration of the heat-retaining container 700> The heat-insulating container 700 is a container for temporarily storing oil. The heat-insulating container 700 is configured to be able to suppress temperature changes of the stored oil, for example, by using a heat-insulating structure or the like.

[0018] <Flow path configuration> The adsorption towers 100 to 400 are connected to inlet flow paths 110, 210, 310, and 410, first outlet flow paths 120, 220, 320, and 420, and second outlet flow paths 130, 230, 330, and 430.

[0019] The inflow channels 110 to 410 are channels for introducing oil into the adsorption towers 100 to 400. The inflow channels 110 to 410 are connected to the first outflow channels 120 to 420 of the adjacent adsorption towers 100 to 400. Specifically, the inflow channel 110 is connected to the first outflow channel 220, the inflow channel 210 is connected to the first outflow channel 320, the inflow channel 310 is connected to the first outflow channel 420, and the inflow channel 410 is connected to the first outflow channel 120. The inflow channels 110 to 410 are also connected to the low-temperature heat medium tank 500 and the high-temperature heat medium tank 600. The flow of oil will be explained together with the explanation of the CO2 capture method.

[0020] The first outlet flow paths 120-420 are flow paths for discharging oil from the adsorption towers 100-400. The first outlet flow paths 120-420 are connected to the above-mentioned inlet flow paths 110-410, the high-temperature heat medium tank 600, and the thermal insulation container 700. In addition, the first outlet flow paths 120, 320 are connected to first compressed gas flow paths 140, 340. Compressed gas is supplied into the adsorption towers 100-400 via the first compressed gas flow paths 140, 340. The compressed gas is used to rapidly discharge oil from the adsorption towers 100-400. The first compressed gas flow paths 140, 340 are connected to first internal pressure adjustment flow paths 150, 350. First check valves Ve1, Ve3 are provided in the first internal pressure adjustment flow paths 150, 350. The first internal pressure adjustment channels 150, 350 allow the increased internal pressure in the adsorption towers 100 to 400 to escape to the outside.

[0021] The second outlet flow paths 130-430 are flow paths for discharging oil from the adsorption towers 100-400. The second outlet flow paths 130-430 are connected to the low-temperature heat medium tank 500 and the high-temperature heat medium tank 600. The second outlet flow paths 130-430 are provided with quick discharge valves Vf1, Vf2, Vf3, and Vf4. When the quick discharge valves Vf1-Vf4 are opened, the oil in the adsorption towers 100-400 is discharged into the low-temperature heat medium tank 500 or the high-temperature heat medium tank 600.

[0022] A second compressed gas flow path 710 is connected to the insulated container 700. Compressed gas is supplied into the insulated container 700 via the second compressed gas flow path 710. The compressed gas is used to discharge oil from the insulated container 700. A second internal pressure adjustment flow path 720 is connected to the second compressed gas flow path 710. A second check valve Vee is provided in the second internal pressure adjustment flow path 720. The second internal pressure adjustment flow path 720 allows the increased internal pressure of the insulated container 700 to escape to the outside.

[0023] Furthermore, supply flow paths 160, 260, 360, and 460 are connected to the thermal insulation container 700. The supply flow paths 160-460 are also connected to the inflow flow paths 110-410, respectively. The oil in the thermal insulation container 700 is supplied to the adsorption towers 100-400 via the supply flow paths 160-460.

[0024] The low-temperature heat medium tank 500 is connected to a first oil flow path 510. The first oil flow path 510 is connected to the inflow paths 110 to 410. A first pump P1 is provided in the first oil flow path 510. When the first pump P1 operates, the oil in the low-temperature heat medium tank 500 is pumped up and supplied to the adsorption towers 100 to 400.

[0025] The high-temperature heat medium tank 600 is connected to a second oil flow path 610. The second oil flow path 610 is connected to the inflow paths 110 to 410. A second pump P2 and a heater HT are provided in the second oil flow path 610. When the second pump P2 operates, the oil in the high-temperature heat medium tank 600 is pumped up and supplied to the adsorption towers 100 to 400. Also, the oil supplied to the adsorption towers 100 to 400 is heated by the heater HT.

[0026] Valves V and check valves RV are provided in the above-described flow paths respectively. By opening and closing the valves V and the check valves RV, the oil flowing through the flow paths is regulated.

[0027] <CO2 recovery method> The CO2 capture method according to the present disclosure is performed as a single process for capturing CO2 from flue gas using the CO2 capture system 1 described above. As shown in FIG. 1, the CO2 capture method includes a pre-cooling step P10, an adsorption step P20, a pre-heating step P30, and a desorption step P40. Each of the adsorption towers 100 to 400 in the CO2 capture system 1 performs these steps consecutively in order. For example, the adsorption tower 100 performs the pre-cooling step P10, the adsorption step P20, the pre-heating step P30, and the desorption step P40 consecutively in this order. After the desorption step P40 is completed, the processes are performed again in order, starting with the pre-cooling step P10. Because the CO2 capture system 1 includes four adsorption towers 100 to 400, the pre-cooling step P10, the adsorption step P20, the pre-heating step P30, and the desorption step P40 are performed in parallel in each of the adsorption towers 100 to 400. In the following, the pre-cooling process P10 will be explained using adsorption tower 100, the adsorption process P20 will be explained using adsorption tower 200, the pre-heating process P30 will be explained using adsorption tower 300, and the desorption process P40 will be explained using adsorption tower 400.

[0028] <Pre-cooling process P10> The pre-cooling step P10 is a step for pre-cooling the adsorbent AD1 in the adsorption tower 100 prior to the subsequent adsorption step P20. The following description starts from the completion of the desorption step P40, which will be described later.

[0029] In the pre-cooling step P10, the rapid discharge valve Vf1 is opened, and compressed gas is supplied to the adsorption tower 100 via the first compressed gas flow path 140. As a result, the relatively high-temperature (e.g., 90°C) oil that filled the adsorption tower 100 at the completion of the desorption step P40 is discharged into the high-temperature heat medium tank 600 via the second outlet flow path 130. After all the oil has been discharged, the rapid discharge valve Vf1 is closed, and the supply of compressed gas is stopped. Subsequently, relatively low-temperature (e.g., 25°C) oil flows into the adsorption tower 100 from the adsorption tower 200, where the adsorption step P20 is being performed, via the first outlet flow path 220 and the inlet flow path 110. At this time, the first check valve Ve1 is opened, thereby preventing an excessive increase in the internal pressure of the adsorption tower 100. After the adsorption tower 100 is filled with relatively low-temperature oil, the first check valve Ve1 is closed.

[0030] By performing the pre-cooling step P10, the temperature of the adsorbent AD1 is cooled to about 30°C.

[0031] <Adsorption process P20> The adsorption step P20 is a step in which exhaust gas is supplied into the adsorption tower 200 and CO2 contained in the exhaust gas is adsorbed by the adsorbent AD2.

[0032] In the adsorption step P20, the valve Vin2 is opened, and exhaust gas is supplied to the gas chamber GR2 of the adsorption tower 200 through the gas supply port IN2. Furthermore, the first pump P1 is operated, and oil cooled in the low-temperature heat transfer medium tank 500 is supplied into the adsorption tower 200 through the first oil passage 510 and the inlet passage 210. The oil in the low-temperature heat transfer medium tank 500 is cooled to 20°C by the cooler CL. The adsorbent AD2 adsorbs CO2 contained in the exhaust gas while being cooled by the oil. The oil is supplied from the low-temperature heat transfer medium tank 500 into the adsorption tower 200, and the oil in the adsorption tower 200 is supplied to the adsorption tower 100, where the pre-cooling step P10 is being performed, through the first outlet passage 220 and the inlet passage 110. Because the adsorption of CO2 by the adsorbent AD2 is an exothermic reaction, the temperature of the oil supplied to the adsorption tower 100 rises to approximately 25°C. The exhaust gas from which CO2 has been removed is discharged to the outside of the adsorption tower 200 via a gas outlet OUT2.

[0033] <Preheating process P30> The preheating step P30 is a step for preheating the adsorbent AD3 in the adsorption tower 300 prior to the subsequent desorption step P40.

[0034] In the preheating step P30, the rapid discharge valve Vf3 is opened, and compressed gas is supplied to the adsorption tower 300 via the first compressed gas flow path 340. As a result, the relatively low-temperature (e.g., 25°C) oil that filled the adsorption tower 300 at the completion of the adsorption step P20 is discharged into the low-temperature heat transfer medium tank 500 via the second outflow flow path 330. After all the oil has been discharged, the rapid discharge valve Vf3 is closed, and the supply of compressed gas is stopped. Subsequently, the second check valve Vee is opened, and compressed gas is supplied to the thermal insulation container 700 via the second compressed gas flow path 710. As a result, the relatively high-temperature (e.g., 100°C) oil in the thermal insulation container 700 is supplied into the adsorption tower 300 via the supply flow path 360 and the inflow flow path 310. When the adsorption tower 300 is filled with oil, the second check valve Vee is closed, and the supply of compressed gas is stopped.

[0035] In the preliminary heating step P30, the temperature of the adsorbent AD3 is heated to about 80°C.

[0036] <Desorption step P40> The desorption step P40 is a step for desorbing CO2 from the adsorbent AD4 and discharging it outside the adsorption tower 400.

[0037] In the desorption step P40, the valve Vout4 is opened, and purge gas is supplied into the adsorption tower 400 through the gas discharge port OUT4. Also, the valve Vin4 is opened, and CO2 is discharged outside the adsorption tower 400 through the gas supply port IN4. Further, when the second pump P2 operates, the oil in the high-temperature heat medium tank 600 is supplied into the adsorption tower 400 through the second oil flow path 610, the heater HT, and the inflow path 410. The oil is heated to a relatively high temperature (for example, 120°C) by the heater HT. The adsorbent AD4 releases the adsorbed CO2 into the gas chamber GR4 by such oil. The released CO2 is discharged outside the adsorption tower 400 by the purge gas. While oil is supplied from the high-temperature heat medium tank 600 into the adsorption tower 400, the oil in the adsorption tower 400 is supplied to the heat preservation container 700 through the first outflow path 420 and the inflow path 410. Since the reaction for desorbing CO2 from the adsorbent AD4 is an endothermic reaction, the temperature of the oil supplied to the heat preservation container 700 is 100°C.

[0038] In the case where the heat preservation container 700 is filled with oil and in the case where oil is supplied from the heat preservation container 700 to the adsorption tower 300 in the above-described preliminary heating step P30, the oil in the adsorption tower 400 is discharged to the high-temperature heat medium tank 600 through the second outflow path 430. Thereby, the retention of the oil flow is suppressed.

[0039] <Cycle of the CO₂ recovery method> FIG. 2 is a diagram illustrating an example of the operation of the CO2 capture system 1 that executes a CO2 capture method. In FIG. 2, the processes performed by each of the four adsorption towers 100-400 are shown in chronological order from left to right. In FIG. 2, the time required for one process to be performed is defined as one cycle time, and four cycle times CT1, CT2, CT3, and CT4 are shown. The black arrows in FIG. 2 indicate increases or decreases in relatively high-temperature oil, while the open arrows indicate increases or decreases in relatively low-temperature oil. Specifically, downward arrows indicate oil being discharged from the adsorption towers 100-400, and upward arrows indicate oil being supplied to the adsorption towers 100-400. The bottom row also shows a schematic representation of the oil volume in the thermally insulated container 700. The "empty" symbol in the bottom row indicates that there is no oil in the thermally insulated container 700, and the "full" symbol indicates that the thermally insulated container 700 is filled with oil. The dashed arrows drawn starting from "FULL" indicate the adsorption towers 100 to 400 to which the oil in the heat-insulating container 700 is supplied.

[0040] 2, the CO2 recovery system 1 performs a pre-cooling process P10, an adsorption process P20, a pre-heating process P30, and a desorption process P40 in parallel during one cycle time. In the adsorption towers 100 to 400, the pre-cooling process P10, the adsorption process P20, the pre-heating process P30, and the desorption process P40 are repeatedly performed in this order.

[0041] <Temperature change of adsorbents AD1 to AD4> Fig. 3 is a graph showing the temperature changes of the adsorbents AD1 to AD4. Fig. 3 also shows the inlet temperatures of the oil supplied to the adsorption towers 100 to 400. Specifically, the oil inlet temperature in the pre-cooling step P10 is 25°C, the oil inlet temperature in the adsorption step P20 is 20°C, the oil inlet temperature in the pre-heating step P30 is 100°C, and the oil inlet temperature in the desorption step P40 is 120°C.

[0042] 3, the temperature of the adsorbent AD3 in the preheating step P30 rises significantly from approximately 30°C to approximately 80°C. This is because, in the preheating step P30, the entire amount of relatively low-temperature oil used in the adsorption step P20 is discharged from the adsorption tower 300 to the low-temperature heat medium tank 500, and the relatively high-temperature oil kept warm in the thermal insulation container 700 is supplied to the adsorption tower 300. In this way, by supplying relatively high-temperature oil after discharging the relatively low-temperature oil, the heat energy of the relatively high-temperature oil can be efficiently used to increase the temperature of the adsorbent AD3. This also makes it possible to relatively increase the temperature of the adsorbent AD4 in the desorption step P40.

[0043] According to the CO2 capture method of the embodiment described above, the preheating step P30 includes discharging the oil used in the adsorption step P20 from the adsorption tower 300 to the low-temperature heat medium tank 500 and supplying the oil kept warm in the thermal insulation container 700 to the adsorption tower 300 to heat the adsorbent AD3. This allows the heat of the oil kept warm in the thermal insulation container 700 to be efficiently transferred to the adsorbent AD3. This allows the desorption step P40 to be performed in a state where the temperature of the adsorbent AD4 has been sufficiently increased. More specifically, in a configuration in which relatively high-temperature oil is supplied to the adsorption tower 300 before the relatively low-temperature oil used in the adsorption step P20 is discharged from the adsorption tower 300, the heat of the relatively high-temperature oil is also used to increase the temperature of the relatively low-temperature oil remaining in the adsorption tower 300. This causes the temperature of the adsorbent AD3 to be lower than the desired temperature, and the time required for the temperature increase is also longer. In contrast, in the CO2 capture method of the embodiment, the heat energy of the relatively high-temperature oil is not used to increase the temperature of the relatively low-temperature oil in the adsorption tower 300, so that the temperature of the adsorbent AD3 can be increased more efficiently. Furthermore, by increasing the temperature of the adsorbent AD3 more efficiently, the amount of CO2 desorbed from the adsorbent AD3 that has adsorbed CO2 in the desorption step P40 can be increased.

[0044] Furthermore, according to the CO2 capture method of the embodiment, in the preheating step P30, after the entire amount of relatively low-temperature oil filling the adsorption tower 300 has been discharged, relatively high-temperature oil is supplied to the adsorption tower 300. Therefore, compared to a configuration in which relatively high-temperature oil is supplied before the entire amount of relatively low-temperature oil in the adsorption tower 300 has been discharged, the temperature of the adsorbent AD3 can be increased more efficiently. Specifically, if relatively high-temperature oil is supplied before the relatively low-temperature oil is discharged, the energy of the relatively high-temperature oil is used to increase the temperature of the relatively low-temperature oil, and the energy supplied to the adsorbent AD3 is reduced. In contrast, in the present embodiment, the use of the energy of the relatively high-temperature oil to increase the temperature of the relatively low-temperature oil is suppressed, so the temperature of the adsorbent AD3 can be increased in a shorter time.

[0045] Furthermore, according to the CO2 recovery method and CO2 recovery system of the embodiment, the low-temperature heat medium tank 500 in which relatively low-temperature oil is stored and the high-temperature heat medium tank 600 in which relatively high-temperature oil is stored are provided separately, thereby improving the energy efficiency in cooling and heating the oil compared to a configuration in which relatively high-temperature oil and relatively low-temperature oil are supplied to a single heat medium tank.

[0046] Furthermore, according to the embodiment of the CO2 recovery method and CO2 recovery system, since an insulated container 700 is provided, the energy required to heat the oil used to heat the adsorbent AD3 in the pre-heating step P30 to a relatively high temperature can be reduced compared to a configuration that does not include an insulated container 700.

[0047] B. Other Embodiments: (B1) In the above embodiment, the heat medium may be any heat medium other than oil.

[0048] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0049] 1...CO2 recovery system, 100, 200, 300, 400...adsorption tower, 110, 210, 310, 410...inlet flow path, 120, 220, 320, 420...first outlet flow path, 130, 230, 330, 430...second outlet flow path, 140, 340...first compressed gas flow path, 150, 350...first internal pressure adjustment flow path, 160, 260, 360, 460...supply flow path, 500...low-temperature heat transfer medium tank, 510...first oil flow path, 600...high-temperature heat transfer medium tank, 610...second oil flow path, 700...thermal insulation container, 710...second compressed gas flow path, 720...second internal pressure adjustment flow path, AD1, AD2, AD3, AD4...adsorbent, CL...cooler, CT1, CT2, CT 3,CT4...cycle time, GR1,GR2,GR3,GR4...gas chamber, HT...heater, IN1,IN2,IN3,IN4...gas supply port, OR1,OR2,OR3,OR4...oil chamber, OUT1,OUT2,OUT3,OUT4...gas discharge port, P1...first pump, P10...pre-cooling process, P2...second pump, P20...adsorption process, P30...pre-heating process, P40...desorption process, RV...check valve, V...valve, Ve1,Ve3...first check valve, Vee...second check valve, Vf1,Vf2,Vf3,Vf4...quick discharge valve, Vin1,Vin2,Vin3,Vin4...valve, Vout1,Vout2,Vout3,Vout4...valve

Claims

[Claim 1] A method for recovering carbon dioxide contained in exhaust gas, comprising: a pre-cooling step of cooling the adsorbent in the adsorption tower using a heat medium; an adsorption step of supplying the exhaust gas to the adsorption tower and causing the adsorbent to adsorb the carbon dioxide; a pre-heating step of heating the adsorbent using a heat medium; and a desorption step of desorbing the carbon dioxide from the adsorbent and recovering the carbon dioxide from the adsorption tower, the pre-cooling step is performed after the desorption step, the adsorption step is performed after the pre-cooling step, the pre-heating step is performed after the adsorption step, and the desorption step is performed after the pre-heating step; the pre-cooling step includes discharging the heat medium used in the desorption step from the adsorption tower into a high-temperature heat medium tank, and supplying the heat medium used in the adsorption step to the adsorption tower to cool the adsorbent, the adsorption step includes supplying a cooled heat medium from a low-temperature heat medium tank to the adsorption tower and cooling the adsorbent using the heat medium; the preheating step includes discharging the heat medium used in the adsorption step from the adsorption tower to the low-temperature heat medium tank, and supplying the heat medium, which is kept warm in a heat-insulating container, to the adsorption tower to heat the adsorbent, the desorption step includes: supplying a heated heat medium from the high-temperature heat medium tank to the adsorption tower and heating the adsorbent using the heat medium; and supplying the heat medium from the adsorption tower to the insulated container. A method for recovering carbon dioxide contained in exhaust gas.

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