CO2 recovery device

Abstract

This will help to limit the size of CO2 capture equipment. [Solution] The CO2 recovery device comprises an H2O recovery unit, an H2O discharge channel, a CO2 recovery unit, a CO2 storage unit, a CO2 storage channel, and a pump. The H2O recovery unit is configured to recover H2O from exhaust gas. The H2O discharge channel guides the H2O removed in the H2O recovery unit to the outside and includes a common section. The CO2 recovery unit is configured to recover CO2 from the exhaust gas from which H2O has been recovered in the H2O recovery unit. The CO2 storage channel guides the CO2 removed in the CO2 recovery unit to the CO2 storage unit and includes a common section. The pump is provided in the common section.

Description

Technical Field

[0006]

[0001] The present disclosure relates to a CO2 recovery device configured to recover CO2 from exhaust gas from an internal combustion engine.

Background Art

[0002] As described in Patent Document 1, a CO2 separation device for removing CO2 from exhaust gas from an internal combustion engine of a vehicle is known. The CO2 separation device includes a water adsorber and a CO2 adsorber. Exhaust gas from the internal combustion engine first flows into the water adsorber, and H2O contained in the exhaust gas is removed by an adsorbent in the water adsorber. Then, the exhaust gas that has passed through the water adsorber flows into the CO2 adsorber, and CO2 contained in the exhaust gas is removed by an adsorbent in the CO2 adsorber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the CO2 separation device of Patent Document 1, a vacuum pump for desorbing H2O from the adsorbent of the water adsorber and a compressor for desorbing CO2 from the adsorbent of the CO2 adsorber are provided, and there is a risk that the device will be enlarged.

[0005] In one aspect of the present disclosure, it is desirable to suppress the enlargement of the CO2 recovery device.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a CO2 recovery device configured to recover CO2 from exhaust gas from an internal combustion engine, comprising: an H2O recovery unit; an H2O discharge channel; a CO2 recovery unit; a CO2 storage unit; a CO2 storage channel; and a pump. The H2O recovery unit is configured to recover H2O from the exhaust gas by adsorbing H2O contained in the exhaust gas with an H2O adsorbent. The H2O discharge channel is a channel that guides the H2O desorbed in the H2O recovery unit to the outside, and is a channel that includes a common section. The CO2 recovery unit is configured to recover CO2 from the exhaust gas from which H2O has been recovered in the H2O recovery unit by adsorbing CO2 contained in the exhaust gas with a CO2 adsorbent. The CO2 storage unit is configured to store CO2. The CO2 storage channel is a channel that guides the CO2 desorbed in the CO2 recovery unit to the CO2 storage unit, and is a channel that includes a common section. The pump is provided in the common section.

[0007] With the above configuration, a single pump can perform both the desorption of H2O from the H2O adsorbent in the H2O recovery section and the desorption of CO2 from the CO2 adsorbent in the CO2 recovery section. Therefore, the size of the CO2 recovery device can be suppressed.

[0008] One aspect of the present disclosure may further include a heating unit configured to heat the H2O recovery unit, a switching unit configured to switch the flow path, and a control unit configured to control the switching unit. The control unit may be configured to switch the flow path using the switching unit to guide the CO2 desorbed in the CO2 recovery unit to the CO2 storage unit, and then execute a CO2 desorption process in which CO2 is desorbed from the CO2 adsorbent using a pump, and to heat the H2O recovery unit with the heating unit while the CO2 desorption process is being executed.

[0009] When the H2O adsorbent in the H2O recovery section reaches a high temperature, H2O becomes more easily desorbed. In contrast, with the above configuration, the H2O adsorbent in the H2O recovery section can be heated using the execution time of the CO2 desorption process. Therefore, the desorption of H2O from the H2O adsorbent in the H2O recovery section and the desorption of CO2 from the CO2 adsorbent in the CO2 recovery section can be efficiently performed with a single pump.

[0010] One aspect of the present disclosure may further include a cooling unit configured to cool the H2O recovery unit. The control unit may be configured to cool the H2O recovery unit with the cooling unit during the execution of the CO2 desorption process.

[0011] Furthermore, when the H2O adsorbent in the H2O recovery section becomes hot, as mentioned above, H2O becomes easier to desorb, but conversely, it becomes more difficult to adsorb H2O. In contrast, with the above configuration, the temperature of the heated H2O adsorbent in the H2O recovery section can be restored to its original temperature by utilizing the execution time of the CO2 desorption treatment, making it possible to create a state where the H2O adsorbent is more likely to adsorb H2O.

[0012] One aspect of this disclosure may further include a plurality of H2O recovery units and a plurality of CO2 recovery units. The H2O discharge channel guides the H2O removed from each H2O recovery unit to the outside, and the common section may be provided in the section where the channels from each H2O recovery unit merge. The CO2 storage channel guides the CO2 removed from each CO2 recovery unit to the CO2 storage unit and has a section where the channels of CO2 from each CO2 recovery unit merge, and this section may include a common section.

[0013] With the above configuration, a single pump can remove H2O from the H2O adsorbent in multiple H2O recovery units and remove CO2 from the CO2 adsorbent in multiple CO2 recovery units. Therefore, the size of the CO2 recovery device can be suppressed. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1A is an explanatory diagram of the CO2 recovery device according to the first embodiment. Figure 1B is a timing chart of the desorption mode according to the first embodiment. [Figure 2] Figure 2A is an explanatory diagram of the CO2 recovery device according to the second embodiment. Figure 2B is a timing chart of the desorption mode according to the second embodiment. [Figure 3] Figure 3 is an explanatory diagram of the CO2 recovery device according to the third embodiment. [Modes for carrying out the invention]

[0015] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First Embodiment] [(1) Overview] The CO2 recovery device 1 of the first embodiment is mounted on a vehicle equipped with an internal combustion engine and is configured to recover CO2 from exhaust gas emitted from the internal combustion engine (see Figure 1A). The vehicle may be, for example, one that uses only an internal combustion engine as a power source, or a hybrid vehicle equipped with an internal combustion engine and a motor. In addition, the CO2 recovery device 1 may be mounted on various machines and equipment equipped with an internal combustion engine instead of a vehicle, for example, on construction machinery equipped with an internal combustion engine. The CO2 recovery device 1 comprises a cooling unit 2, first and second H2O recovery units 3A, 3B, first and second CO2 recovery units 4A, 4B, a CO2 storage unit 5, a pump 6, a control unit 7, and a heating and cooling unit 8.

[0016] [(2) Configuration of the flow path] The CO2 recovery device 1 comprises the first to seventh flow paths P01 to P07 and the first to ninth desorption flow paths P11 to P19, which are gas flow paths formed by members such as pipes, and the first to eighth valves V1 to V8, which function as switching units to switch the flow path through which the gas passes (see Figure 1A). The first to eighth valves V1 to V8 are configured as three-way valves, for example.

[0017] The first flow path P01 receives exhaust gas from the internal combustion engine from its starting point, and its end is connected to the first valve V1. A cooling section 2 is also provided in the first flow path P1. The second and third channels P02 and P03 are each connected at their starting end to the first valve V1 and at their ending end to the second valve V2. The second channel P02 is provided with a first H2O recovery section 3A, and the third channel P03 is provided with a second H2O recovery section 3B.

[0018] The fourth flow path P04 has its starting end connected to the second valve V2 and its ending end connected to the third valve V3. The fifth and sixth flow paths P05 and P06 each have a starting end connected to the third valve V03 and a terminal end connected to the fourth valve V4. Further, a first CO2 recovery unit 4A is provided in the fifth flow path P05, and a second CO2 recovery unit 4B is provided in the sixth flow path P06.

[0019] The seventh flow path P07 has a starting end connected to the fourth valve V, and a terminal end open to the outside of the vehicle. The first separation flow path P11 has a starting end connected to the first H2O recovery unit 3A and a terminal end connected to the fifth valve V5.

[0020] The second separation flow path P12 has a starting end connected to the second H2O recovery unit 3B and a terminal end connected to the fifth valve V5. The third separation flow path P13 has a starting end connected to the fifth valve V5 and a terminal end connected to the seventh valve V7. That is, at the starting end of the third separation flow path P13, the first and second separation flow paths P11 and P12 merge.

[0021] The fourth separation flow path P14 has a starting end connected to the first CO2 recovery unit 4A and a terminal end connected to the sixth valve V6. The fifth separation flow path P15 has a starting end connected to the second CO2 recovery unit 4B and a terminal end connected to the sixth valve V6.

[0022] The sixth separation flow path P16 has a starting end connected to the sixth valve V6 and a terminal end connected to the seventh valve V7. That is, at the starting end of the sixth separation flow path P16, the fourth and fifth separation flow paths P14 and P15 merge.

[0023] The seventh separation flow path P17 has a starting end connected to the seventh valve V7 and a terminal end connected to the eighth valve V8. Further, a pump 6 is provided in the seventh separation flow path P17. The eighth separation flow path P18 has a starting end connected to the eighth valve V8 and a terminal end open to the outside of the vehicle.

[0024] The ninth desorption channel P19 has its starting end connected to the eighth valve V8 and its end connected to the CO2 storage section 5. In other words, the first to third, seventh and eighth desorption channels P11 to P13, P17 and P18 are desorbed in the first and second H2O recovery sections 3A and 3B, and become H2O discharge channels that guide the H2O that flows out from the first and second H2O recovery sections 3A and 3B to the outside of the vehicle. Also, the fourth to seventh and ninth desorption channels P14 to P17 and P19 are desorbed in the first and second CO2 recovery sections 4A and 4B, and become CO2 storage channels that guide the CO2 that flows out from the first and second CO2 recovery sections 4A and 4B to the CO2 storage section 5.

[0025] Furthermore, the seventh desorption channel P17 is a channel common to both the H2O discharge channel and the CO2 storage channel, and is a common section where the channels from the first and second H2O recovery sections 3A and 3B and the first and second CO2 recovery sections 4A and 4B merge.

[0026] [(3) Cooling section] The cooling unit 2 is configured, for example, to cool the exhaust gas flowing down the first flow path P01 by exchanging heat between the refrigerant and the exhaust gas (see Figure 1A). The cooling unit 2 may use a dedicated refrigerant, or it may use a refrigerant used in other parts of the vehicle. Furthermore, the cooling unit 2 may also cool the exhaust gas by blowing air with a fan, for example.

[0027] [(4) First and Second H2O Recovery Sections] The first and second H2O recovery units 3A and 3B are equipped with an H2O adsorbent such as silica gel, zeolite, or activated alumina. The first H2O recovery unit 3A recovers H2O from the exhaust gas by adsorbing the H2O contained in the exhaust gas flowing in from the second flow path P02 using the H2O adsorbent. The first H2O recovery unit 3A then discharges the exhaust gas from which H2O has been recovered into the second flow path P02. Similarly, the second H2O recovery unit 3B recovers H2O from the exhaust gas flowing down the third flow path P03, and then discharges the exhaust gas into the third flow path P03.

[0028] In other words, the first and second H2O recovery units 3A and 3B remove H2O from the exhaust gas from which CO2 is recovered in the first and second CO2 recovery units 4A and 4B. This prevents the H2O in the exhaust gas from being adsorbed by the CO2 adsorbent in the first and second CO2 recovery units 4A and 4B, thus suppressing a decrease in the CO2 adsorption effect of the CO2 adsorbent.

[0029] [(5) Heating and cooling section] The heating and cooling unit 8 has the function of a heating unit that heats the first and second H2O recovery units 3A and 3B, and the function of a cooling unit that cools the first and second H2O recovery units 3A and 3B. The heating and cooling unit 8 may heat the first and second H2O recovery units 3A and 3B by means of a heater, for example, or by heat exchange with a heat transfer medium. The heating and cooling unit 8 may also cool the first and second H2O recovery units 3A and 3B by heat exchange with a refrigerant, for example. The heating and cooling unit 8 may also cool the first and second H2O recovery units 3A and 3B by airflow from a fan, for example.

[0030] [(6) First and Second CO2 Recovery Sections] The first and second CO2 recovery units 4A and 4B are equipped with CO2 adsorbents such as zeolite, MOF, activated carbon, magnesium oxide, solid amine, calcium oxide, etc. (see Figure 1A). The first CO2 recovery unit 4A recovers CO2 from the exhaust gas by adsorbing the CO2 contained in the exhaust gas flowing in from the fifth flow path P05 using the CO2 adsorbent. The first CO2 recovery unit 4A then discharges the exhaust gas from which CO2 has been recovered into the fifth flow path P05. Similarly, the second CO2 recovery unit 4B recovers CO2 from the exhaust gas flowing down the sixth flow path P06 in the same manner as the first CO2 recovery unit 4A, and then discharges the exhaust gas into the sixth flow path P06.

[0031] [(7) CO2 storage section] The CO2 storage unit 5 is configured to store CO2 recovered from exhaust gas by the first and second CO2 recovery units 4A and 4B (see Figure 1A). The CO2 storage unit 5 may, for example, be equipped with a CO2 adsorbent similar to that of the first and second CO2 recovery units 4A and 4B, and store CO2 by adsorption onto the CO2 adsorbent, or it may be configured as a cylinder.

[0032] [(8) Pump] Pump 6 is configured to desorb H2O from the H2O adsorbent in the first and second H2O recovery sections 3A and 3B and discharge the desorbed H2O outside the vehicle (see Figure 1A). Pump 6 is also configured to desorb CO2 from the CO2 adsorbent in the first and second CO2 recovery sections 4A and 4B and store it in the storage section 5.

[0033] Hereafter, the first and second H2O recovery units will be referred to simply as H2O recovery units, and the first and second CO2 recovery units will be referred to simply as CO2 recovery units. Furthermore, the H2O recovery unit and the CO2 recovery unit will be referred to simply as recovery units. Also, H2O and CO2 will be referred to as recovered gases. Furthermore, the H2O adsorbent and the CO2 adsorbent will be referred to simply as adsorbents.

[0034] More specifically, pump 6 depressurizes the space where the H2O adsorbent is located in any of the H2O recovery sections via the first to third and seventh desorption channels P11 to P13 and P17, thereby creating a vacuum and desorbing H2O from the H2O adsorbent. Pump 6 then discharges the desorbed H2O outside the vehicle via the seventh and eighth desorption channels P17 and P18.

[0035] Furthermore, pump 6 depressurizes the space where the CO2 adsorbent is located in any of the CO2 recovery sections via the 4th to 7th desorption channels P14 to P17, thereby creating a vacuum and desorbing CO2 from the CO2 adsorbent. Pump 6 then causes the desorbed CO2 to flow into the CO2 storage section 5 via the 7th and 9th desorption channels P17 and P19, and stores the CO2 in the CO2 storage section 5.

[0036] [(9) Control Unit] The control unit 7 is configured to control various parts of the CO2 recovery device 1, such as the first to eighth valves V1 to V8 and the pump 6, by transmitting signals to these parts, and includes a CPU and memory (see Figure 1A). The CPU executes a program stored in the memory, thereby realizing various functions of the CO2 recovery device 1. Note that the various functions realized by the control unit 7 are not limited to being realized by program execution; some or all of them may be realized using one or more hardware components.

[0037] [(10) Processing of CO2 recovery equipment] The control unit 7 sets one of the first and second H2O recovery units 3A and 3B to an adsorption state and the other to a desorption state, and also sets one of the first and second CO2 recovery units 4A and 4B to an adsorption state and the other to a desorption state (see Figure 1A). Then, at a predetermined switching timing, the control unit 7 switches the H2O recovery unit and the CO2 recovery unit to either the adsorption state or the desorption state. Note that the switching of the adsorption state and desorption state of the H2O recovery unit and the switching of the adsorption state and desorption state of the CO2 recovery unit are performed simultaneously.

[0038] Then, in the H2O recovery section, which is in an adsorption state, H2O is recovered from the exhaust gas, and in the CO2 recovery section, which is in an adsorption state, CO2 is recovered from the exhaust gas. Meanwhile, in the H2O recovery section and the CO2 recovery section, which are in a desorption state, H2O or CO2 is desorbed by the pump 6.

[0039] <Switching timing> The switching timing between the H2O recovery unit and the CO2 recovery unit may be the timing when the remaining amount of recoverable gas that can be adsorbed in at least one of the H2O recovery unit or the CO2 recovery unit, which is in an adsorption state, becomes low.

[0040] Specifically, for example, based on the amount of adsorbent provided in each recovery unit, the operating time of the recovery unit (hereinafter referred to as the upper limit time) at which the remaining amount of recoverable gas that can be adsorbed by at least one of the H2O recovery unit and the CO2 recovery unit becomes low may be predetermined. Then, after setting the H2O recovery unit and the CO2 recovery unit to the adsorption state, the timing when the operating time reaches the upper limit time may be used as the switching timing.

[0041] Alternatively, for example, the control unit 7 may use sensors to detect the concentration of the recovered gas contained in the exhaust gas in the downstream flow path of each recovery unit that is in an adsorption state, and the timing when the concentration exceeds a threshold may be used as the switching timing.

[0042] <First and Second Cycles> The control unit 7 has a first and a second cycle. In the first cycle, the first H2O recovery unit 3A and the first CO2 recovery unit 4A are in an adsorption state, while the second H2O recovery unit 3B and the second CO2 recovery unit 4B are in a desorption state (see Figure 1A). In the second cycle, the second H2O recovery unit 3B and the second CO2 recovery unit 4B are in an adsorption state, while the first H2O recovery unit 3A and the first CO2 recovery unit 4A are in a desorption state. The first and second cycles are then switched at the switching timing described above.

[0043] In the first cycle, the control unit 7 controls the valves as follows: The first valve V1 connects the end of the first flow path P01 to the beginning of the second flow path P02 and closes the beginning of the third flow path P03. The second valve V2 connects the end of the second flow path P02 to the beginning of the fourth flow path P04 and closes the end of the third flow path P03.

[0044] Furthermore, the third valve V3 connects the end of the fourth flow path P04 to the beginning of the fifth flow path P05 and closes the beginning of the sixth flow path P06. Also, the fourth valve V4 connects the end of the fifth flow path P05 to the beginning of the seventh flow path P07 and closes the end of the sixth flow path P06.

[0045] Furthermore, the fifth valve V5 connects the end of the second deactivation channel P12 to the beginning of the third deactivation channel P13 and closes the end of the first deactivation channel P11. Also, the sixth valve V6 connects the end of the fifth deactivation channel P15 to the beginning of the sixth deactivation channel P16 and closes the end of the fourth deactivation channel P14. The control of the seventh and eighth valves V7 and V8 will be described later.

[0046] On the other hand, in the second cycle, the control unit 7 controls the valves as follows: The first valve V1 connects the end of the first flow path P01 to the beginning of the third flow path P03 and closes the beginning of the second flow path P02. The second valve V2 connects the end of the third flow path P03 to the beginning of the fourth flow path P04 and closes the end of the second flow path P02.

[0047] Furthermore, the third valve V3 connects the end of the fourth flow path P04 to the beginning of the sixth flow path P06 and closes the beginning of the fifth flow path P05. Also, the fourth valve V4 connects the end of the sixth flow path P06 to the beginning of the seventh flow path P07 and closes the end of the fifth flow path P05.

[0048] Furthermore, the fifth valve V5 connects the end of the first deactivation channel P11 to the beginning of the third deactivation channel P13 and closes the end of the second deactivation channel P12. The sixth valve V6 connects the end of the fourth deactivation channel P14 to the beginning of the sixth deactivation channel P16 and closes the end of the fifth deactivation channel P15. The control of the seventh and eighth valves V7 and V8 will be described later.

[0049] <Collection unit in the adsorbed state> Next, we will explain the flow of exhaust gas in which H2O and CO2 are recovered by the recovery unit in an adsorption state during each of the first and second cycles (see Figure 1A).

[0050] In the first cycle, the exhaust gas flowing into the first flow path P01 is cooled in the cooling unit 2, then passes through the first valve V1 and the second flow path P02, and flows into the first H2O recovery unit 3A, where H2O is in an adsorbed state. After H2O is recovered in the first H2O recovery unit 3A, the exhaust gas flows out of the first H2O recovery unit 3A, passes through the second flow path P02, the second valve V2, the fourth flow path P04, the third valve V3, and the fifth flow path P05, and flows into the first CO2 recovery unit 4A, where CO2 is in an adsorbed state. After CO2 is recovered in the first CO2 recovery unit 4A, the exhaust gas flows out of the first CO2 recovery unit 4A, passes through the fifth flow path P05, the fourth valve V4, and the seventh flow path P07, and flows out of the vehicle.

[0051] Meanwhile, in the second cycle, the exhaust gas flowing into the first flow path P01 is cooled in the cooling unit 2, then passes through the first valve V1 and the third flow path P03, and flows into the second H2O recovery unit 3B, where it is in an adsorbed state. After H2O is recovered in the second H2O recovery unit 3B, the exhaust gas flows out of the second H2O recovery unit 3B, passes through the third flow path P03, the third valve V3, the fourth flow path P04, the third valve V3, and the sixth flow path P06, and flows into the second CO2 recovery unit 4B, where it is in an adsorbed state. After CO2 is recovered in the second CO2 recovery unit 4B, the exhaust gas flows out of the second CO2 recovery unit 4B, passes through the sixth flow path P06, the fourth valve V4, and the seventh flow path P07, and flows out of the vehicle.

[0052] [(11) Detachable recovery unit] Next, we will explain the desorption of H2O and CO2 in the recovery section, which is in a desorption state, during each of the first and second cycles (see Figure 1A).

[0053] <Steps 1-3> The control unit 7 controls the 7th and 8th valves V7 and V8 in each cycle to perform desorption in the H2O recovery unit and the CO2 recovery unit in a predetermined order, thereby switching the gas flow paths from the H2O recovery unit and the CO2 recovery unit that are in a desorption state. In other words, the control unit 7 switches the recovery unit that is in communication with the pump 6 among the H2O recovery unit and the CO2 recovery unit that are in a desorption state. As an example, the control unit 7 sequentially executes the 1st to 3rd steps (see Figure 1B).

[0054] In the first step, the seventh valve V7 connects the end of the sixth desorption channel P16 to the beginning of the seventh desorption channel P17 and closes the end of the third desorption channel P13. Also, the eighth valve V8 connects the end of the seventh desorption channel P17 to the beginning of the ninth desorption channel P19 and closes the beginning of the eighth desorption channel P18. As a result, the desorption state CO2 recovery unit and the pump 6 are in communication, and the pump 6 is in communication with the CO2 storage unit 5.

[0055] The control unit 7 then operates the pump 6 to desorb CO2 from the CO2 recovery unit and stores the desorbed CO2 in the CO2 storage unit 5, performing a CO2 desorption process. In addition, while the CO2 desorption process is being performed, the control unit 7 heats the H2O recovery unit with the heating and cooling unit 8.

[0056] In the subsequent second step, the seventh valve V7 connects the end of the third desorption passage P13 to the beginning of the seventh desorption passage P17 and closes the end of the sixth desorption passage P16. The eighth valve V8 connects the end of the seventh desorption passage P17 to the beginning of the eighth desorption passage P18 and closes the end of the ninth desorption passage P19. As a result, the desorbed H2O recovery unit and the pump 6 are in communication, and the pump 6 is connected to the outside of the vehicle.

[0057] The control unit 7 operates the pump 6 to perform an H2O desorption process to desorb H2O from the H2O recovery unit, and also discharges the desorbed H2O outside the vehicle. At this time, the CO2 recovery unit enters a standby state, and no processing related to the CO2 recovery unit is performed.

[0058] In the subsequent third step, the seventh and eighth valves V7 and V8 are in the same state as in the first step. The control unit 7 performs the same CO2 desorption process as in the first step, and while the CO2 desorption process is being performed, the heating and cooling unit 8 cools the H2O recovery unit.

[0059] After the third step is completed, the control unit 7 switches the cycle, and the H2O recovery unit and CO2 recovery unit, which have undergone desorption, enter an adsorption state and recover H2O and CO2. The control unit 7 then performs the first to third steps in the same manner on the newly desorbed H2O recovery unit and CO2 recovery unit to desorb H2O and CO2.

[0060] <Gas flow in each cycle> In the first cycle, the second H2O recovery unit 3B and the second CO2 recovery unit 4B become detached.

[0061] Then, in the first and third steps of the first cycle, the CO2 released from the second CO2 recovery unit 4B by the pump 6 passes through the fifth desorption channel P15, the sixth valve V16, the sixth desorption channel P16, the seventh valve V7, the seventh desorption channel P17, the eighth valve V8, and the ninth desorption channel P19, flows into the CO2 storage unit 5, and is stored in the CO2 storage unit 5.

[0062] In the second step, the H2O that flows out from the second H2O recovery unit 3B by the pump 6 passes through the second desorption passage P12, the fifth valve V15, the third desorption passage P13, the seventh valve V7, the seventh desorption passage P17, the eighth valve V8, and the eighth desorption passage P18, and is discharged outside the vehicle.

[0063] On the other hand, in the second cycle, the first HO recovery unit 3A and the first CO2 recovery unit 4A become detached. Then, in the first and third steps of the second cycle, the CO2 released from the first CO2 recovery unit 4A by the pump 6 passes through the fourth desorption channel P14, the sixth valve V16, the sixth desorption channel P16, the seventh valve V7, the seventh desorption channel P17, the eighth valve V8, and the ninth desorption channel P19, flows into the CO2 storage unit 5, and is stored in the CO2 storage unit 5.

[0064] In the second step, the H2O that flows out from the first H2O recovery section 3A by the pump 6 passes through the first desorption passage P11, the fifth valve V15, the third desorption passage P13, the seventh valve V7, the seventh desorption passage P17, the eighth valve V8, and the eighth desorption passage P18, and is discharged outside the vehicle.

[0065] [2. Second Embodiment] [(1) Overview] The CO2 recovery device 1 of the second embodiment differs from the first embodiment in that it further includes a heating and cooling unit for heating and cooling the first and second CO2 recovery units 4A and 4B (see Figure 2A). In addition, the CO2 recovery device 1 of the second embodiment differs from the first embodiment in the process for desorbing H2O and CO2 in the recovery unit, which is in a desorbed state. The differences between the CO2 recovery device 1 of the second embodiment and the first embodiment will be described below.

[0066] [(2) Heating and cooling section] The CO2 recovery device 1 of the second embodiment includes a first heating and cooling unit 8A that heats and cools the first and second H2O recovery units 3A and 3B, and a second heating and cooling unit 8B that heats and cools the first and second CO2 recovery units 4A and 4B (see Figure 2A). The first and second heating and cooling units 8A and 8B have the same configuration as the heating and cooling unit of the first embodiment.

[0067] [(3) Steps 1-3] In the second embodiment as well, in each cycle, the control unit 7 sequentially executes the first to third steps in order to desorb H2O and CO2 in the recovery unit, which is in a desorption state (see Figure 2B).

[0068] In the first step, the seventh and eighth valves V7 and V8 are in the same state as in the first embodiment, which connects the desorbed CO2 recovery unit with the pump 6, and also connects the pump 6 with the CO2 storage unit 5.

[0069] Then, the control unit 7 heats the CO2 recovery unit, which is in a desorbed state, with the second heating / cooling unit 8B for a predetermined time, and then performs the CO2 desorption process. In addition, while the heating of the CO2 recovery unit and the CO2 desorption process are being performed, the control unit 7 heats the H2O recovery unit, which is in a desorbed state, with the first heating / cooling unit 8A.

[0070] The second step is carried out in the same manner as in the first embodiment. In the subsequent third step, the seventh and eighth valves V7 and V8 enter the same state as in the first step. The control unit 7 then performs the same CO2 desorption process as in the first step, and after the CO2 desorption process, the second heating and cooling unit 8B cools the CO2 recovery unit, which is in the desorbed state. In addition, while the CO2 desorption process and the cooling of the CO2 recovery unit are being performed, the control unit 7 cools the H2O recovery unit, which is in the desorbed state, with the first heating and cooling unit 8A.

[0071] Then, after the third step is completed, the control unit 7 switches the cycle, as in the first embodiment, and the H2O recovery unit and CO2 recovery unit, from which desorption has occurred, enter an adsorption state. The control unit 7 then performs the first to third steps in the same manner on the newly desorbed H2O recovery unit and CO2 recovery unit to desorb H2O and CO2.

[0072] [3. Third Embodiment] [(1) Overview] The CO2 recovery device 1 of the third embodiment differs from the first embodiment in that it is provided with first to third auxiliary flow paths P21 to 23 and a ninth valve V9 (see Figure 3). Furthermore, the CO2 recovery device 1 of the third embodiment differs from the first embodiment in the H2O desorption process. The differences between the CO2 recovery device 1 of the third embodiment and the first embodiment will be described below.

[0073] [(2) Configuration of the flow path] The first to third auxiliary flow paths P21 to P23 are configured in the same way as the flow paths in the first embodiment (see Figure 3). In addition, the ninth valve V9 has the same function as the valve in the first embodiment, and also has the function of adjusting the opening degree of the starting end of the first auxiliary flow path P21 and the opening degree of the starting end of the second auxiliary flow path P22.

[0074] The first auxiliary channel P21 has its starting end connected to the ninth valve V9 and its ending end connected to the first H2O recovery section 3A. The second auxiliary channel P22 has its starting end connected to the ninth valve V9 and its ending end connected to the second H2O recovery section 3B.

[0075] The third auxiliary flow path P23 has its starting end open to the outside of the vehicle and its end is connected to the ninth valve V9. [(3) H2O elimination treatment] In the third embodiment as well, the control unit 7 sequentially executes the first to third steps on the recovery unit, which is in a desorbed state, in each of the first and second cycles (see Figure 3). However, the H2O desorption process performed on the H2O recovery unit in the second step differs from that in the first embodiment.

[0076] In the second step, the control unit 7 controls the seventh and eighth valves V7 and V8 in the same manner as in the first embodiment, so that the H2O recovery unit, which is in a desorption state, is in communication with the pump 6, and the pump 6 is in communication with the outside of the vehicle. Furthermore, the control unit 7 controls the ninth valve V9 to close the starting end (hereafter referred to as the air inlet) of the first and second auxiliary flow paths P21 and P22 that extend from the H2O recovery unit, which is in a desorption state. Then, the control unit 7 starts the H2O desorption process and operates the pump 6 to desorb H2O from the H2O recovery unit and discharge the desorbed H2O outside the vehicle.

[0077] In the H2O desorption process, the control unit 7 determines whether the pressure in the space where the H2O adsorbent is placed in the H2O recovery unit (hereinafter referred to as internal pressure), which is in a desorbed state, is below a predetermined threshold (hereinafter referred to as the depressurization threshold).

[0078] In other words, in the H2O recovery section, immediately after the pump 6 starts operating, as the internal pressure decreases, the amount of H2O desorbed from the H2O adsorbent per unit time (in other words, the desorption rate) increases. However, as the internal pressure decreases further and the H2O recovery section becomes almost a vacuum, the flow of gas in the space where the H2O adsorbent is located is suppressed, and the H2O desorbed from the H2O adsorbent accumulates near the adsorbent. As a result, the desorption of H2O is suppressed, and the desorption rate decreases. The pressure reduction threshold may be, for example, the value of the internal pressure at which the desorption rate begins to decrease.

[0079] Therefore, for example, the time from the start of operation of the pump 6 in the H2O desorption process until it is estimated that the internal pressure has fallen below a pressure reduction threshold (hereinafter referred to as the pressure reduction time) may be predetermined. The control unit 7 may then determine that the internal pressure has fallen below a pressure reduction threshold when the pressure reduction time has elapsed from the start of operation of the pump 6. Alternatively, for example, the control unit 7 may determine whether or not the internal pressure has fallen below a pressure reduction threshold by periodically detecting the internal pressure using a sensor.

[0080] Then, when the pressure in the H2O recovery unit falls below the pressure reduction threshold, the control unit 7 increases the opening of the air inlet using the ninth valve V9, introducing air from outside the vehicle into the H2O recovery unit. At this time, the air inlet is opened to a degree that maintains a reduced internal pressure (hereafter referred to as the low-pressure opening).

[0081] Specifically, for example, the low-pressure opening may be a preset value, or the ninth valve V9 may be controlled based on the internal pressure detected by the sensor so that the atmospheric inlet is at the low-pressure opening.

[0082] Subsequently, the control unit 7 completes the H2O elimination process and proceeds to the third step. This promotes gas flow in the space where the H2O adsorbent is located in the H2O recovery section, which is in a desorbed state. Therefore, it suppresses the accumulation of desorbed H2O near the H2O adsorbent, which reduces the desorption rate, and promotes the desorption of H2O.

[0083] [(4) Modified Version] In the modified configuration, the control unit 7 controls the ninth valve V9 to open the air inlet and start the H2O desorption process. At this time, the same control is performed so that the air inlet opens to the low pressure setting described above. In other words, during the H2O desorption process, air flows into the space where the H2O adsorbent is placed in the H2O recovery section, which is in a desorbed state, through the air inlet to an extent that maintains a low internal pressure.

[0084] Furthermore, the CO2 recovery device 1 may not include a third auxiliary flow path P23 and a ninth valve V9, and the starting ends of the first auxiliary flow path P21 and the second auxiliary flow path P22, which constitute the air inlet, may be open to the outside of the vehicle. In addition, a closure section may be provided at the air inlet, and the closure section may cause the air inlet to open to a low pressure.

[0085] Even with such a configuration, the elimination of H2O by the H2O elimination treatment can be promoted. [4. Effects] (1) According to the above embodiment, a single pump 6 can remove H2O from the H2O adsorbent in the first and second H2O recovery units 3A and 3B, and remove CO2 from the CO2 adsorbent in the first and second CO2 recovery units 4A and 4B. Therefore, the size of the CO2 recovery device 1 can be suppressed. In addition, the cost and energy consumption of the CO2 recovery device 1 can be reduced.

[0086] (2) Furthermore, a relatively large amount of energy is required for the desorption of H2O from the H2O adsorbent. When the H2O adsorbent in the H2O recovery section becomes hot, H2O is more easily desorbed, but conversely, it becomes more difficult for H2O to be adsorbed.

[0087] In contrast, in the first step performed on the H2O recovery section and CO2 recovery section, which are in a desorbed state, the H2O recovery section is heated. Therefore, the H2O adsorbent can be heated using the execution time of the CO2 desorption process, and the desorption of H2O from the H2O adsorbent and the desorption of CO2 from the CO2 adsorbent in the CO2 recovery section can be efficiently performed with a single pump.

[0088] (3) Furthermore, in the third step performed on the H2O recovery section and CO2 recovery section, which are in a desorbed state, the H2O recovery section is cooled, and then these recovery sections enter an adsorption state. Therefore, the time spent on the CO2 desorption process is used to return the temperature of the heated H2O adsorbent to its original state, making it easier for the H2O adsorbent to adsorb H2O. Thus, the adsorption and desorption of H2O and CO2 can be efficiently performed with a single pump.

[0089] (4) Furthermore, the CO2 recovery device 1 is equipped with two H2O recovery units and two CO2 recovery units, and these recovery units are detached by a single pump. This helps to keep the CO2 recovery device from becoming too large.

[0090] [5. Other Embodiments] (1) In the above embodiment, the number of H2O recovery units and the number of CO2 recovery units provided in the CO2 recovery device 1 may be one or three or more, respectively. The number of H2O recovery units and the number of CO2 recovery units may also be different. In addition, in the same manner as in the above embodiment, one pump may be provided in the common section between the H2O discharge channel from one H2O recovery unit or each of the multiple H2O recovery units and the CO2 storage channel from one CO2 recovery unit or each of the multiple CO2 storage channels. Then, in the same manner as in the above embodiment, the H2O recovery unit and the CO2 recovery unit in the desorbed state may be desorbed by one pump.

[0091] (2) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Also, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments. [Explanation of Symbols]

[0092] 1...CO2 recovery unit, 2...Cooling unit, 3A...First H2O recovery unit, 3B...Second H2O recovery unit, 4A...First CO2 recovery unit, 4B...Second CO2 recovery unit, 5...CO2 storage unit, 6...Pump, 7...Control unit, 8...Heating and cooling unit, 8A...First heating and cooling unit, 8B...Second heating and cooling unit, P01~P07...First to seventh flow paths, P11~P19...First to ninth desorption flow paths, P21~P23...First to third auxiliary flow paths, V1~V9...First to ninth valves.

Claims

1. A CO2 recovery device configured to recover CO2 from exhaust gas from an internal combustion engine, An H2O recovery unit is configured to recover H2O from the exhaust gas by adsorbing H2O contained in the exhaust gas with an H2O adsorbent, A flow path for guiding the H2O removed in the H2O recovery section to the outside, the H2O discharge flow path being a flow path that includes a common section, A CO2 recovery unit is configured to recover CO2 from the exhaust gas by adsorbing the CO2 contained in the exhaust gas from which H2O has been recovered in the H2O recovery unit using a CO2 adsorbent, A CO2 storage unit configured to store CO2, A flow path for guiding the CO2 removed in the CO2 recovery section to the CO2 storage section, the flow path being a CO2 storage flow path including the common section, A pump installed in the aforementioned common section, A CO2 recovery device equipped with the following features.

2. A CO2 recovery device according to claim 1, A heating unit configured to heat the H2O recovery unit, A switching unit configured to switch the flow path, The system further comprises a control unit configured to control the switching unit, The control unit is configured to switch the flow path using the switching unit to guide the CO2 removed in the CO2 recovery unit to the CO2 storage unit, then perform a CO2 desorption process using the pump to remove CO2 from the CO2 adsorbent, and to heat the H2O recovery unit using the heating unit while the CO2 desorption process is being performed. CO2 recovery device.

3. A CO2 recovery device according to claim 2, The system further includes a cooling unit configured to cool the H2O recovery unit, The control unit is configured to cool the H2O recovery unit with the cooling unit while the CO2 desorption process is being performed. CO2 recovery device.

4. A CO2 recovery device according to any one of claims 1 to 3, Multiple H2O recovery units, Multiple CO2 recovery units, Furthermore, The H2O discharge channel guides the H2O removed from each of the H2O recovery sections to the outside, and the common section is provided in the section where the channels from each of the H2O recovery sections merge. The CO2 storage channel guides the CO2 released from each of the CO2 recovery sections to the CO2 storage section, and has a section where the CO2 channels from each of the CO2 recovery sections merge, and this section includes the common section. CO2 recovery device.

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