CO2 recovery device, CO2 recovery method and control procedure

Abstract

The CO2 recovery apparatus disclosed herein alternately and repeatedly performs CO2 adsorption by an adsorption unit and CO2 desorption by a recovery unit, and includes a measuring unit and a control unit. The measuring unit measures the amount of CO2 adsorbed by the adsorption unit and the amount of CO2 desorbed by the recovery unit, and the control unit controls the amount of CO2 desorbed by the recovery unit so that, in cases where the adsorption of CO2 by the adsorption unit and the desorption of CO2 by the recovery unit are alternately and repeatedly performed for three or more cycles, the average residual rate of CO2 adsorbed on each CO2 adsorbent in at least the first to third cycles is shown to be in the range of 40.9% to 80.6%.

Description

Technical Field

[0001] This disclosure relates to a CO2 recovery device, a CO2 recovery method, and a control procedure. Background Technology

[0002] The development of CO2 recovery devices for recovering CO2 (carbon dioxide) from the atmosphere is underway. For example, Patent Document 1 discloses a flue gas decarbonization device that determines the carbon dioxide flow rate in the exhaust gas based on the exhaust gas flow rate and the carbon dioxide concentration in the exhaust gas, and adjusts the ratio of the flow rate of the regenerated amine adsorption liquid supplied to the carbon dioxide adsorption tower to the carbon dioxide flow rate to a constant, and also adjusts the ratio of the steam flow rate of the heater to the amine adsorption liquid flow rate to a constant.

[0003] Prior art literature Patent documents Patent Document 1: Japanese Patent No. 3212524 Summary of the Invention However, in the device disclosed in Patent Document 1, if the desorption temperature set when desorbing CO2 from the adsorbent liquid containing CO2 is increased in order to improve the CO2 recovery efficiency, there is a problem of increased energy consumption.

[0004] This disclosure is an invention made in view of the above background, and its object is to provide a CO2 recovery device, CO2 recovery method and control program that can efficiently recover CO2 without increasing energy consumption.

[0005] The CO2 recovery apparatus disclosed herein comprises: an adsorption section having a CO2 adsorbent composed of an amino-containing CO2 adsorbent and a plurality of porous supports loaded with the CO2 adsorbent, wherein CO2 contained in a gas supplied from the outside is adsorbed onto the CO2 adsorbent; and a recovery section that, by adjusting the adsorption section to a temperature higher than that during CO2 adsorption, desorbs and recovers CO2 adsorbed onto the CO2 adsorbent, wherein the CO2 recovery apparatus alternately and repeatedly performs the CO2 adsorption achieved by the adsorption section and the recovery performed by the recovery section. The CO2 recovery device further comprises: a measuring unit that measures the amount of CO2 adsorbed by the adsorption unit and the amount of CO2 desorbed by the recovery unit; and a control unit that controls the amount of CO2 desorbed by the recovery unit so that, in cases where the adsorption of CO2 by the adsorption unit and the desorption of CO2 by the recovery unit are alternately repeated for three or more cycles, the average residual rate of CO2 adsorbed on the CO2 adsorbent in each of the first to third cycles is shown to be in the range of 40.9% to 80.6%. This CO2 recovery device can efficiently recover CO2 without raising the desorption temperature to a necessary level. In other words, this CO2 recovery device can efficiently recover CO2 without increasing the energy consumption caused by the desorption temperature.

[0006] The CO2 residue rate is the ratio of the amount of CO2 adsorbed on the CO2 adsorbent after CO2 desorption achieved by the recovery unit to the amount of CO2 adsorbed on the CO2 adsorbent before CO2 desorption achieved by the recovery unit.

[0007] Alternatively, the CO2 adsorption conditions achieved by the adsorption unit in each cycle can be set to the same conditions, and the CO2 desorption conditions achieved by the recovery unit in each cycle can also be set to the same conditions.

[0008] Alternatively, the adsorption of CO2 by the adsorption unit and the desorption of CO2 by the recovery unit can be alternately repeated for five or more cycles.

[0009] Alternatively, the recovery section can be further configured such that by adjusting the adsorption section to a lower pressure compared to the adsorption of CO2, the CO2 adsorbed on the CO2 adsorbent is desorbed from the CO2 adsorbent and recovered.

[0010] Alternatively, the recovery section can be further configured to desorb and recover CO2 adsorbed on the CO2 adsorbent by adjusting the adsorption section to a higher humidity level compared to the adsorption of CO2.

[0011] Alternatively, the plurality of porous carriers may be configured to have a plurality of pores with an average pore diameter of 2 nm to 200 nm, and are coated on a substrate having a honeycomb shape.

[0012] Alternatively, the plurality of porous carriers may be configured to have a plurality of pores with an average pore diameter of 2 nm to 200 nm and to have a particle shape.

[0013] Alternatively, the plurality of porous carriers may be configured such that either silicon dioxide or aluminum oxide is used as the main component.

[0014] Alternatively, the CO2 adsorbent can be a polyamine or an amino-containing compound containing the polyamine, wherein the polyamine comprises any one of polyethyleneimine, methylated polyethyleneimine, isopropylated polyethyleneimine, polyallylamine, pentaethylenehexamine, methylated pentaethylenehexamine, isopropylated pentaethylenehexamine, tetraethylenepentamine, methylated tetraethylenepentamine, and isopropylated tetraethylenepentamine.

[0015] The CO2 recovery method disclosed herein is a CO2 recovery method implemented by a CO2 recovery device, wherein the CO2 recovery device comprises: an adsorption section having a CO2 adsorbent composed of an amino-containing CO2 adsorbent and a plurality of porous carriers loaded with the CO2 adsorbent, and CO2 contained in a gas supplied from the outside is adsorbed onto the CO2 adsorbent; and a recovery section that, by adjusting the adsorption section to a temperature higher than that during CO2 adsorption, desorbs the CO2 adsorbed on the CO2 adsorbent from the CO2 adsorbent and recovers it. The CO2 recovery device alternately and repeatedly performs CO2 adsorption by the adsorption unit and CO2 desorption by the recovery unit. In this CO2 recovery method, the amount of CO2 desorbed by the recovery unit is controlled so that, when the adsorption and desorption of CO2 by the adsorption unit are alternately and repeatedly performed for three or more cycles, the average residual rate of CO2 adsorbed on the CO2 adsorbent in each of the first to third cycles is shown to be in the range of 40.9% to 80.6%. This CO2 recovery method can efficiently recover CO2 without raising the desorption temperature to a necessary level. In other words, this CO2 recovery method can efficiently recover CO2 without increasing the energy consumption caused by the desorption temperature.

[0016] The control program disclosed herein enables a computer to perform CO2 recovery processing by a CO2 recovery device, wherein the CO2 recovery device comprises: an adsorption section having a CO2 adsorbent composed of an amino-containing CO2 adsorbent and a plurality of porous carriers loaded with the CO2 adsorbent, and adsorbing CO2 contained in a gas supplied from the outside onto the CO2 adsorbent; and a recovery section that, by adjusting the adsorption section to a temperature higher than that during CO2 adsorption, desorbs and recovers CO2 adsorbed on the CO2 adsorbent from the CO2 adsorbent, and the CO2 recovery device alternately and repeatedly performs the processing performed by the adsorption section. The control program, which performs CO2 adsorption and desorption by the recovery unit, causes a computer to perform the following processes: measuring the amount of CO2 adsorbed by the adsorption unit and the amount of CO2 desorbed by the recovery unit; and controlling the amount of CO2 desorbed by the recovery unit so that, in cases where the adsorption and desorption processes are alternately repeated for at least three cycles, the average residual rate of CO2 adsorbed on the CO2 adsorbent in each of the first to third cycles is within the range of 40.9% to 80.6%. This control program enables efficient CO2 recovery without raising the desorption temperature to a necessary level. In other words, this control program enables efficient CO2 recovery without increasing energy consumption due to the desorption temperature.

[0017] According to this disclosure, a CO2 recovery device, CO2 recovery method, and control program that can efficiently recover CO2 without increasing energy consumption can be provided. Attached Figure Description

[0018] Figure 1 This is a block diagram illustrating a structural example of the CO2 recovery device according to Embodiment 1.

[0019] Figure 2 This is a flowchart illustrating the operation of the CO2 recovery device according to Embodiment 1.

[0020] Figure 3 A graph showing the test results of the CO2 desorption rate in a single cycle of CO2 recovery processing performed by the CO2 recovery device according to Embodiment 1.

[0021] Figure 4 A graph showing the test results of the amount of CO2 adsorbed and desorbed in each cycle of multiple cycles of CO2 recovery treatment performed by the CO2 recovery device according to Embodiment 1.

[0022] Figure 5 This is a diagram illustrating an example of the molecular structure of the CO2 adsorbent used in the CO2 adsorbent of the CO2 recovery apparatus according to Embodiment 1.

[0023] Figure 6 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the first test results.

[0024] Figure 7 A graph showing the change in total CO2 adsorption achieved by multiple cycles of CO2 recovery treatment in the first experimental results.

[0025] Figure 8 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the first test results.

[0026] Figure 9 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the second experiment.

[0027] Figure 10 This is a graph illustrating the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the second experiment.

[0028] Figure 11 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the second experiment.

[0029] Figure 12 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the third experiment.

[0030] Figure 13 This is a graph illustrating the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the third experiment.

[0031] Figure 14 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the third experiment.

[0032] Figure 15 This is a graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the fourth experiment.

[0033] Figure 16 This is a graph illustrating the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the fourth experiment.

[0034] Figure 17A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the fourth experiment.

[0035] Figure 18 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the results of the seventh experiment.

[0036] Figure 19 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the seventh experiment.

[0037] Figure 20 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the results of the seventh experiment.

[0038] Figure 21 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the results of the eighth experiment.

[0039] Figure 22 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the eighth experiment.

[0040] Figure 23 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the results of the eighth experiment.

[0041] Figure 24 This is a graph summarizing the results of multiple experiments.

[0042] Figure 25 A graph showing the relationship between the ratio d / b of CO2 desorption in the tenth cycle to CO2 desorption in the first cycle and the ratio d / a of CO2 adsorption in the tenth cycle to CO2 adsorption in the first cycle, for multiple experimental results.

[0043] Figure 26 A graph showing the relationship between the average CO2 residue rate (c) after CO2 desorption treatment from the first cycle to the third cycle, and the ratio (d / b) of the CO2 desorption amount in the tenth cycle to the CO2 desorption amount in the first cycle, for multiple experimental results.

[0044] Figure 27 This is a graph showing the relationship between the average CO2 residue rate (c) after CO2 desorption treatment from the first cycle to the third cycle, and the ratio (d / a) of the CO2 desorption amount in the tenth cycle to the CO2 adsorption amount in the first cycle, for multiple experimental results.

[0045] Figure 28This is a graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the tenth experiment.

[0046] Figure 29 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the results of the tenth experiment.

[0047] Figure 30 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the tenth experiment. Detailed Implementation

[0048] The present invention will now be described through embodiments thereof, but the invention as described in the claims is not limited to these embodiments. Furthermore, not all structures described in the embodiments are necessary means to solve the problem. For clarity, the following description and drawings have been appropriately omitted and simplified. In the drawings, the same symbols are used for the same elements, and repeated descriptions have been omitted as necessary.

[0049] <Implementation Method 1> Figure 1 This is a block diagram illustrating a structural example of the CO2 recovery apparatus 1 according to Embodiment 1. The CO2 recovery apparatus 1 is an apparatus for recovering CO2 by alternately and repeatedly performing CO2 adsorption and CO2 desorption processes. Specifically, the CO2 recovery apparatus 1 includes a CO2 adsorption unit 11, a CO2 recovery unit 12, a measuring unit 13, and a control unit 14.

[0050] The CO2 adsorption unit 11 adsorbs CO2 (carbon dioxide) contained in gas (exhaust gas or atmosphere) supplied from the outside onto the CO2 adsorbent 111. After a portion of the CO2 is recovered by the CO2 adsorbent 111, the gas is discharged to the outside of the CO2 recovery device 1.

[0051] CO2 adsorbent 111 is composed of an amino-containing CO2 adsorbent and multiple porous supports loaded with the CO2 adsorbent. The porous supports use either silica or alumina as the main component and have multiple pores with an average pore size of 2 nm to 200 nm. For example, the porous supports are coated on a substrate with a honeycomb shape. Alternatively, the porous supports may have a particulate shape.

[0052] The CO2 adsorbent is a polyamine or an amino-containing compound containing polyamine, wherein the polyamine includes any one of polyethyleneimine, methylated polyethyleneimine, isopropylated polyethyleneimine, polyallylamine, pentaethylenehexamine, methylated pentaethylenehexamine, isopropylated pentaethylenehexamine, tetraethylenepentamine, methylated tetraethylenepentamine, and isopropylated tetraethylenepentamine.

[0053] The CO2 recovery unit 12 desorbs and recovers CO2 adsorbed on the CO2 adsorbent 11 by adjusting the CO2 adsorption unit 11 (more specifically, the housing space of the CO2 adsorbent 111 disposed in the CO2 adsorption unit 11) to a higher temperature than during CO2 adsorption, thereby desorbing CO2 from the CO2 adsorbent 111. Alternatively, the CO2 recovery unit 12 may not only adjust the CO2 adsorption unit 11 to a higher temperature than during CO2 adsorption, but also adjust the pressure of the CO2 adsorption unit 11 to a lower pressure than during CO2 adsorption, or adjust the CO2 partial pressure by allowing the flow of gases such as water vapor, thereby desorbing and recovering CO2 adsorbed on the CO2 adsorbent 111. Therefore, for example, the CO2 recovery unit 12 includes a temperature regulating unit for adjusting the temperature of the CO2 adsorption unit 11, a pressure regulating unit for adjusting the pressure of the CO2 adsorption unit 11, and a humidity regulating unit for adjusting the humidity of the CO2 adsorption unit 11.

[0054] The measuring unit 13 measures the amount of CO2 adsorbed by the CO2 adsorption unit 11 and the amount of CO2 desorbed by the CO2 recovery unit 12. Furthermore, the measuring unit 13 calculates the CO2 residue amount and CO2 residue rate, which will be described later, based on the CO2 adsorption amount and CO2 desorption amount.

[0055] First, the measuring unit 13 measures the amount of CO2 adsorbed on the CO2 adsorbent 111 at the end of the CO2 adsorption treatment performed by the CO2 adsorption unit 11, based on the residual amount of CO2 P adsorbed (residual) on the CO2 adsorbent 111 before the start of the CO2 adsorption treatment performed by the CO2 adsorption unit 11, and the amount of CO2 adsorbed on the CO2 adsorbent 111 from the start of the CO2 adsorption treatment performed by the CO2 adsorption unit 11 until the end of the CO2 adsorption treatment. Furthermore, the amount of CO2 adsorbed Q is calculated based on the difference between the amount of CO2 contained in the gas supplied to the CO2 adsorption unit 11 from the outside before CO2 recovery treatment and the amount of CO2 contained in the gas discharged from the CO2 adsorption unit 11 after CO2 recovery treatment.

[0056] Subsequently, the measuring unit 13 measures the residual amount of CO2 on the CO2 adsorbent 111 (=RS) based on the amount of CO2 adsorbed on the CO2 adsorbent 111 at the end of the CO2 adsorption treatment performed by the CO2 adsorption unit 11 and the amount of CO2 desorbed from the CO2 adsorbent 111 by the CO2 desorption treatment performed by the CO2 recovery unit 12. Then, the measuring unit 13 calculates the ratio of the residual amount of CO2 on the CO2 adsorbent 111 after the CO2 desorption treatment performed by the CO2 recovery unit 12 to the amount of CO2 adsorbed on the CO2 adsorbent 111 at the end of the CO2 adsorption treatment performed by the CO2 adsorption unit 11, i.e., T / R.

[0057] The control unit 14 alternately and repeatedly controls the CO2 adsorption process performed by the CO2 adsorption unit 11 and the CO2 desorption process performed by the CO2 recovery unit 12. In addition, the control unit 14 also sets the respective processing conditions (temperature, pressure, humidity, etc.) for the CO2 adsorption process and the CO2 desorption process.

[0058] Furthermore, in any cycle of CO2 recovery processing, the control unit 14 transfers the CO2 adsorbed on the CO2 adsorbent 111 to the next cycle of CO2 recovery processing in a state where a portion of the CO2 is not recovered but remains.

[0059] Specifically, the control unit 14 controls the amount of CO2 desorption S achieved by the CO2 recovery unit 12 during the CO2 recovery process, at least from the first cycle to the third cycle, so that the average value of the CO2 residue rate T / R adsorbed on the CO2 adsorbent 111 is in the range of 40.9% to 80.6%. The specific value of the CO2 residue rate T / R will be described later.

[0060] Therefore, compared to the case where all CO2 adsorbed on the CO2 adsorbent 11 is recovered in one cycle of CO2 recovery treatment and then transferred to the next cycle of CO2 recovery treatment, the CO2 recovery device 1 can desorb and recover a sufficiently high proportion of CO2 from the CO2 adsorbent 111 at a lower temperature in the next cycle of CO2 recovery treatment. In other words, the CO2 recovery device 1 can efficiently recover CO2 without increasing the energy consumption caused by the desorption temperature.

[0061] <Operation of CO2 Recovery Unit 1> Next, use Figure 2 The operation of CO2 recovery device 1 will be explained. Figure 2 A flowchart illustrating the operation of CO2 recovery device 1.

[0062] First, the CO2 recovery device 1 performs a first cycle of CO2 recovery processing. In this first cycle, the CO2 recovery device 1 begins adsorption processing of CO2 contained in the gas supplied from the outside to the housing space of the CO2 adsorbent 111 (step S101). Specifically, the CO2 recovery device 1 adsorbs CO2 contained in the gas supplied from the outside to the housing space of the CO2 adsorbent 111 onto the CO2 adsorbent 111. The gas, after a portion of the CO2 has been recovered by the CO2 adsorbent 111, is discharged to the outside of the CO2 recovery device 1.

[0063] For example, after a predetermined adsorption treatment time of approximately 5 minutes, the CO2 recovery device 1 ends the CO2 adsorption treatment (step S102). At this time, the CO2 recovery device 1 calculates the amount of CO2 adsorbed on the CO2 adsorbent 111 at the end of the CO2 adsorption treatment by adding the amount of CO2 adsorbed on the CO2 adsorbent 111 from the start of the CO2 adsorption treatment to the end of the CO2 adsorption treatment, i.e., the amount of CO2 adsorbed on the CO2 adsorbent 111 before the CO2 desorption treatment is to be performed.

[0064] When the CO2 adsorption treatment is completed, the CO2 recovery device 1 then performs a CO2 desorption treatment. Specifically, firstly, the CO2 recovery device 1 performs vacuuming, oxygen purging, and heating of the housing space of the CO2 adsorbent 111 (step S103). Therefore, in the CO2 desorption treatment, the housing space of the CO2 adsorbent 111 is adjusted to a higher temperature compared to the CO2 adsorption treatment. Furthermore, in the CO2 desorption treatment, the housing space of the CO2 adsorbent 111 can also be adjusted to a lower pressure, or the CO2 partial pressure can be adjusted to a lower pressure by allowing the flow of gases such as water vapor, compared to the CO2 adsorption treatment. Thus, the CO2 adsorbed on the CO2 adsorbent 111 begins to desorb (step S104).

[0065] Here, the CO2 recovery device 1 calculates the ratio of the amount of CO2 residue T remaining on the CO2 adsorbent 111 after the CO2 desorption treatment to the amount of CO2 adsorbed on the CO2 adsorbent 111 at the end of the CO2 adsorption treatment, i.e., the CO2 residue rate T / R (step S105).

[0066] Then, the CO2 recovery device 1 controls the desorption process so that the average CO2 residual rate T / R from at least the first cycle to the third cycle is within a range of less than a predetermined ratio α (and more than a predetermined ratio β) (step S106). Alternatively, the CO2 recovery device 1 may control not only the desorption process but also the adsorption process so that the average CO2 residual rate T / R from at least the first cycle to the third cycle is within a range of less than a predetermined ratio α (and more than a predetermined ratio β). Then, the CO2 recovery device 1 terminates the CO2 desorption process and cools the containment space of the CO2 adsorbent 111 to reduce the temperature (step S107). The predetermined ratios α and β satisfy the condition α > β and both represent any value within the range of 40.9% to 80.6%.

[0067] Subsequently, while continuing CO2 recovery treatment ("Yes" in step S108), the CO2 recovery device 1 performs a second cycle of CO2 recovery treatment (steps S101 to S108). Furthermore, the CO2 residue P adsorbed (residual) on the CO2 adsorbent 111 before the start of the second cycle of CO2 adsorption treatment represents the CO2 residue T remaining on the CO2 adsorbent 111 after the first cycle of CO2 desorption treatment. Then, if the CO2 recovery treatment is not to continue ("No" in step S108), the CO2 recovery treatment ends.

[0068] Therefore, compared to the case where all CO2 adsorbed on the CO2 adsorbent 11 is recovered in one cycle of CO2 recovery treatment and then transferred to the next cycle of CO2 recovery treatment, the CO2 recovery device 1 can desorb and recover a sufficiently high proportion of CO2 from the CO2 adsorbent 111 at a lower temperature in the next cycle of CO2 recovery treatment. In other words, the CO2 recovery device 1 can efficiently recover CO2 without increasing the energy consumption caused by the desorption temperature.

[0069] Figure 3 This is a graph showing the test results of the CO2 desorption rate in a single cycle of CO2 recovery treatment performed by CO2 recovery unit 1. Figure 3 In the example, the horizontal axis represents the desorption treatment time, and the vertical axis represents the CO2 desorption rate. Figure 3 In the experiment, polyethyleneimine (PEI) was used as an amine-based CO2 adsorbent. Furthermore, in the CO2 desorption process, the pressure was reduced to 3 kPa, and the partial pressure of CO2 was lowered by supplying water vapor, with the temperature set to any one of 100°C, 90°C, or 80°C. Figure 3In the experiment, the amount of CO2 adsorbed on CO2 adsorbent 111 before the start of CO2 recovery treatment (before the start of CO2 adsorption treatment) was very small. Therefore, it can be considered that this CO2 recovery treatment is the same as the CO2 recovery treatment performed under the condition that the CO2 residual rate T / R in the previous cycle of CO2 recovery treatment was very low.

[0070] like Figure 3 As shown, the CO2 desorption rate after a 600-second desorption process following adsorption was approximately 70% at a set temperature of 100°C. In contrast, at a set temperature of 80°C, the rate was less than half, approximately 30%, compared to the 100°C rate. This means that, generally speaking, increasing the desorption temperature is necessary to improve CO2 recovery efficiency, which increases energy consumption.

[0071] Figure 4 This is a graph showing the experimental results of CO2 adsorption and desorption in each cycle of multiple CO2 recovery processes performed by CO2 recovery unit 1. Figure 4 In the example, the horizontal axis represents the number of CO2 recovery cycles, and the vertical axis represents the amount of CO2 adsorbed and desorbed. Figure 4 In the experiment, polyethyleneimine was used as an amine-based CO2 adsorbent. Furthermore, in the CO2 adsorption treatment, at a temperature set at 30°C, simulated atmospheric air at a volumetric flow rate (SV) of 2.4E+5 / h was circulated through the CO2 adsorbent 111 for 5 minutes, thereby adsorbing CO2 onto the adsorbent 111. Subsequently, a CO2 desorption treatment was performed for 5 minutes at a temperature set at 80°C.

[0072] like Figure 4 As shown, although the CO2 desorption amount in the first cycle is relatively small, the CO2 desorption amount increases with the number of cycles, resulting in the CO2 desorption amount in the fifth cycle and beyond being more than twice that of the first cycle. Therefore, by transferring a portion of the CO2 adsorbed on the CO2 adsorbent to the next cycle of CO2 recovery processing in any given cycle without recovery, a sufficiently high proportion of CO2 can be desorbed from the CO2 adsorption unit 11 and recovered in the next cycle at a lower temperature. In other words, the CO2 recovery device 1 can efficiently recover CO2 without increasing energy consumption.

[0073] Experimental content and results of CO2 recovery and treatment Next, the experimental content and results of CO2 recovery treatment will be explained. Based on these experimental results, the CO2 residual rate for each cycle suitable for CO2 recovery device 1 will be derived.

[0074] <Experimental materials used in the experiment> In the CO2 recovery and treatment experiment, two test materials were used as CO2 adsorbent 111.

[0075] The first experimental material used as CO2 adsorbent 111 was formed by loading polyethyleneimine (branched Mw=600) onto a porous carrier to achieve an amine weight / (amine weight + silica weight) = 0.35. The porous carrier was a porous carrier obtained by coating 50 g / L of silica gel onto the surface of a cordierite substrate with a pore size of 8 mm in diameter × 50 mm in thickness, a pore density of 400 pores / square inch, and a wall thickness of 4.5 mils.

[0076] The second experimental material used as CO2 adsorbent 111 was formed by loading isopropylated polyethyleneimine onto a porous carrier to a weight of amine / (weight of amine + weight of silica gel) = 0.35. The porous carrier was a porous carrier obtained by coating 50 g / L of silica gel onto the surface of a cordierite substrate with a pore size of 8 mm in diameter × 50 mm in thickness, a pore density of 400 pores / square inch, and a wall thickness of 4.5 mils.

[0077] Figure 5 This diagram illustrates the molecular structure of the CO2 adsorbent loaded on each of the two test materials (CO2 adsorbent 111) used in the CO2 recovery treatment experiment. Figure 5 The upper side shows the molecular structure of polyethyleneimine (PEI). Figure 5 The molecular structure of isopropylated polyethyleneimine (IP-PEI) is shown on the lower side.

[0078] <Experimental Conditions> In the CO2 recovery and treatment experiment, CO2 adsorption treatment and CO2 desorption treatment were performed alternately and repeatedly.

[0079] First, in the CO2 adsorption treatment, either dry adsorption or humidified adsorption is performed.

[0080] In the dry adsorption process, CO2 was adsorbed onto the test material (CO2 adsorbent 111) by circulating a simulated gas with a volumetric flow rate (SV) of 2.39E+5 / h for 5 minutes at a temperature set at 30°C. Here, the simulated gas used was a dried gas containing 400 ppm CO2 added to pure nitrogen. The CO2 adsorption capacity was calculated based on the difference between the CO2 concentration (400 ppm) of the simulated gas supplied to the honeycomb (CO2 adsorbent 111) and the CO2 concentration of the simulated gas passing through the honeycomb, along with the gas flow rate. Although a HORIBAMEX A-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0081] In the humidified adsorption process, with the temperature set at 30°C, CO2 was adsorbed onto any of the aforementioned test materials (CO2 adsorbent 111) by circulating a simulated gas with a volumetric flow rate (SV) of 2.39E+5 / h for 5 minutes. Here, the simulated gas used was a gas containing 400 ppm CO2 added to pure nitrogen and humidified to a relative humidity of 60%–70%. The CO2 adsorption capacity was calculated based on the difference between the CO2 concentration (400 ppm) of the simulated gas supplied to the honeycomb (CO2 adsorbent 111) and the CO2 concentration of the simulated gas passing through the honeycomb, as well as the gas flow rate. Although a HORIBA MEXA-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0082] Next, in the CO2 desorption process, either dry desorption or reduced pressure steam desorption will be performed.

[0083] In the dry desorption process, CO2 adsorbed on the test material (CO2 adsorbent 111) was desorbed by circulating pure nitrogen gas at a volumetric flow rate SV = 4.77E+4 / h through a thermostatic bath heated to a predetermined temperature for 5 minutes. The amount of CO2 desorbed was calculated based on the gas flow rate and the concentration of CO2 contained in the pure nitrogen gas passing through the honeycomb (CO2 adsorbent 111). Although a HORIBA MEXA-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0084] In the reduced-pressure steam desorption process, CO2 adsorbed on the test material (CO2 adsorbent 111) was desorbed by circulating 0.013 g / min of steam (by weight) in a constant-temperature bath heated to a predetermined temperature and reduced to 3 kPa for 5 minutes. The amount of carbon dioxide desorbed was calculated based on the flow rate of the gas diluted by merging steam passing through the honeycomb with nitrogen at a flow rate of 2 L / min, and the concentration of carbon dioxide contained in the diluted gas. Although a HORIBA MEXA-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0085] In addition, as an additional experiment, a saturated adsorption treatment experiment was conducted. The test conditions for the saturated adsorption treatment were the same as those for the CO2 adsorption treatment, except for the supply time of the simulated gas. In the saturated adsorption treatment experiment, the apparent saturated adsorption amount of CO2 was measured after the simulated gas was continuously supplied until the CO2 concentration of the simulated gas passing through the honeycomb no longer changed.

[0086] <First Experimental Results (Example 1)> The results of the first test on CO2 recovery treatment are described. In the first test, a first test material containing polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 80°C were alternately repeated for ten cycles.

[0087] Figure 6 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the first test results. Figure 7 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the first experimental results. Additionally, in... Figure 7 The saturated adsorption capacity of CO2 is also shown. Figure 8 This is a graph showing the CO2 residue rate in each cycle of the CO2 recovery treatment in the first experiment. Additionally, in Figure 8 In addition to the CO2 residual rate, the table also shows the saturated CO2 adsorption capacity p, the total CO2 adsorption capacity q in the tenth cycle, and the q / p ratio. Furthermore, the results of the first experiment also... Figure 24 The results of the first to ninth experiments are summarized in a graph.

[0088] In the first experimental results, the CO2 adsorption capacity *a* in the first cycle was 0.0407 g per gram of CO2 adsorbent, the CO2 desorption capacity *b* in the first cycle was 0.0176 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first cycle to the third cycle was 56.2%. The CO2 residue rate after the second cycle was as follows... Figure 8 As shown. The CO2 desorption amount d in the tenth cycle is 0.0350 g per gram of CO2 adsorbent. The rate of change d / b = 2.01, and the rate of change d / a = 0.87.

[0089] <Second Experiment Results (Example 2)> The results of the second test on CO2 recovery treatment are described. In the second test, a second test material containing isopropylated polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 60°C were alternately repeated for ten cycles.

[0090] Figure 9 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the second experiment. Figure 10 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the second experiment. Additionally, in... Figure 10 The saturated adsorption capacity of CO2 is also shown. Figure 11 This is a graph showing the CO2 residue rate in each cycle of the CO2 recovery treatment in the second experiment. Additionally, in... Figure 11 In addition to the CO2 residual rate, the saturated CO2 adsorption capacity p, the total CO2 adsorption capacity q in the tenth cycle, and the q / p value are also shown. Furthermore, the results of the second experiment also... Figure 24 The results of the first to ninth experiments are summarized in a graph.

[0091] In the second experiment, the CO2 adsorption capacity *a* of the first cycle was 0.0277 g per gram of CO2 adsorbent, the CO2 desorption capacity *b* of the first cycle was 0.0118 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first cycle to the third cycle was 56.4%. The CO2 residue rate after the second cycle is as follows... Figure 11 As shown. The CO2 desorption amount d in the tenth cycle is 0.0240 g per gram of CO2 adsorbent. The rate of change d / b = 2.03, and the rate of change d / a = 0.87.

[0092] <Results of the Third Experiment (Example 3)> The results of the third test on CO2 recovery treatment are described. In the third test, the first test material containing polyethyleneimine was used, and dry adsorption treatment and dry desorption treatment at a temperature set at 80°C were alternately repeated for ten cycles.

[0093] Figure 12 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the third experiment. Figure 13 This is a graph illustrating the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the third experiment. Figure 14 This is a graph showing the CO2 residue rate in each cycle of the CO2 recovery treatment in the third experiment. Additionally, in... Figure 14 In addition to the CO2 residual rate, the table also shows the saturated CO2 adsorption capacity p, the total CO2 adsorption capacity q in the tenth cycle, and the q / p ratio. Furthermore, the results of the third experiment also... Figure 24 The results of the first to ninth experiments are summarized in a graph.

[0094] In the third experiment, the CO2 adsorption capacity *a* of the first cycle was 0.0314 g per gram of CO2 adsorbent, the CO2 desorption capacity *b* of the first cycle was 0.0120 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first cycle to the third cycle was 64.8%. The CO2 residue rate after the second cycle was as follows... Figure 14 As shown. The CO2 desorption amount d in the tenth cycle is 0.0216 g per gram of CO2 adsorbent. The rate of change d / b = 1.80, and the rate of change d / a = 0.69.

[0095] <Results of the Fourth Experiment (Example 4)> The results of the fourth test on CO2 recovery treatment are described. In the fourth test, the first test material containing polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 70°C were alternately repeated for ten cycles.

[0096] Figure 15 This is a graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the fourth experiment. Figure 16 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the fourth experiment. Additionally, in... Figure 16 The saturated adsorption capacity of CO2 is also shown. Figure 17 This is a graph showing the CO2 residue rate in each cycle of the CO2 recovery treatment in the fourth experiment. Additionally, in... Figure 17In addition to the CO2 residual rate, the saturated CO2 adsorption capacity p, the total CO2 adsorption capacity q in the tenth cycle, and the q / p value are also shown. Furthermore, the results of the fourth experiment also... Figure 24 The results of the first to ninth experiments are summarized in a graph.

[0097] In the fourth experiment, the CO2 adsorption capacity *a* of the first cycle was 0.0447 g per gram of CO2 adsorbent, the CO2 desorption capacity *b* of the first cycle was 0.0149 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first cycle to the third cycle was 73.9%. The CO2 residue rate after the second cycle was as follows... Figure 17 As shown. The CO2 desorption amount d in the tenth cycle is 0.0267 g per gram of CO2 adsorbent. The rate of change d / b = 1.79, and the rate of change d / a = 0.60.

[0098] <Fifth Experiment Results (Example 5)> The results of the fifth test on CO2 recovery treatment are described. In the fifth test, the first test material containing polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 67°C were alternately repeated for ten cycles.

[0099] The results of the fifth experiment will Figure 24 The results of the first to ninth experiments are summarized in a graph. In the fifth experiment, the CO2 adsorption amount *a* in the first cycle was 0.0391 g per gram of CO2 adsorbent, the CO2 desorption amount *b* in the first cycle was 0.0125 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first to the third cycle was 77.0%. The CO2 desorption amount *d* in the tenth cycle was 0.0218 g per gram of CO2 adsorbent. The rate of change *d / b* = 1.74, and the rate of change *d / a* = 0.56.

[0100] <Results of the Sixth Experiment (Example 6)> The results of the sixth test on CO2 recovery treatment are described. In the sixth test, the first test material containing polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 60°C were alternately repeated for ten cycles.

[0101] The results of the sixth test are also in progress. Figure 24The results of the first to ninth experiments are summarized in a graph. In the sixth experiment, the CO2 adsorption amount *a* in the first cycle was 0.0425 g per gram of CO2 adsorbent, the CO2 desorption amount *b* in the first cycle was 0.0082 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first to the third cycle was 80.3%. The CO2 desorption amount *d* in the tenth cycle was 0.0220 g per gram of CO2 adsorbent. The rate of change *d / b* = 2.63, and the rate of change *d / a* = 0.51.

[0102] <Results of the Seventh Experiment (Comparative Example 1)> The results of the seventh test on CO2 recovery treatment are described. In the seventh test, the second test material containing isopropylated polyethyleneimine was used, and humidified adsorption treatment and dry desorption treatment at a temperature set at 60°C were alternately repeated for ten cycles.

[0103] Figure 18 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the results of the seventh experiment. Figure 19 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the seventh experiment. Additionally, in... Figure 19 The saturated adsorption capacity of CO2 is also shown. Figure 20 This is a graph showing the CO2 residue rate in each cycle of the CO2 recovery treatment in the seventh experiment. Additionally, in... Figure 20 In addition to the CO2 residual rate, the table also shows the saturated CO2 adsorption capacity p, the total CO2 adsorption capacity q in the tenth cycle, and the q / p ratio. Furthermore, the results of the seventh experiment also... Figure 24 The results of the first to ninth experiments are summarized in a graph.

[0104] In the results of the seventh experiment, the CO2 adsorption capacity *a* in the first cycle was 0.0314 g per gram of CO2 adsorbent, the CO2 desorption capacity *b* in the first cycle was 0.0025 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first cycle to the third cycle was 87.7%. The CO2 residue rate after the second cycle was as follows... Figure 20 As shown. The CO2 desorption amount d in the tenth cycle is 0.0130 g per gram of CO2 adsorbent. The rate of change d / b = 5.19, and the rate of change d / a = 0.42.

[0105] <Results of the Eighth Experiment (Comparative Example 2)> The results of the eighth test on CO2 recovery treatment are described. In the eighth test, the second test material containing isopropylated polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 80°C were alternately repeated for ten cycles.

[0106] Figure 21 A graph showing the amount of CO2 adsorbed and desorbed in each cycle of the CO2 recovery treatment in the results of the eighth experiment. Figure 22 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the eighth experiment. Figure 23 This is a graph showing the CO2 residue rate in each cycle of the CO2 recovery treatment in the eighth experiment. Additionally, in... Figure 23 In addition to the CO2 residual rate, the saturated CO2 adsorption capacity p, the total CO2 adsorption capacity q of the tenth cycle, and the q / p value are also shown. Furthermore, the results of the eighth experiment also... Figure 24 The results of the first to ninth experiments are summarized in a graph.

[0107] In the results of the eighth experiment, the CO2 adsorption capacity *a* of the first cycle was 0.0311 g per gram of CO2 adsorbent, the CO2 desorption capacity *b* of the first cycle was 0.0260 g per gram of CO2 adsorbent, and the average CO2 residue rate *c* from the first cycle to the third cycle was 4.4%. The CO2 residue rate after the second cycle was as follows... Figure 23 As shown. The CO2 desorption amount d in the tenth cycle is 0.0330 g per gram of CO2 adsorbent. The rate of change d / b = 1.26, and the rate of change d / a = 1.05.

[0108] <Results of the Ninth Experiment (Comparative Example 3)> The results of the ninth test on CO2 recovery treatment are described. In the ninth test, the first test material containing polyethyleneimine was used, and humidification adsorption treatment and depressurized steam desorption treatment at a temperature set at 100°C were alternately repeated for ten cycles.

[0109] The results of the ninth test will Figure 24 The results of the first to ninth experiments are summarized in a graph. In the ninth experiment, the CO2 adsorption amount *a* in the first cycle was 0.0463 g per gram of CO2 adsorbent, the CO2 desorption amount *b* in the first cycle was 0.0334 g per gram of CO2 adsorbent, and the average CO2 residual rate *c* from the first to the third cycle was 35.2%. The CO2 desorption amount *d* in the tenth cycle was 0.0360 g per gram of CO2 adsorbent. The rate of change *d / b* = 1.08, and the rate of change *d / a* = 0.78.

[0110] Figure 24 This is a graph summarizing the results of experiments one through nine. (Refer to...) Figures 6 to 23 and Figure 24 The results shown in the first to ninth experiments (Examples 1 to 6) indicate that while the CO2 desorption was relatively low in the first cycle of CO2 recovery treatment, the CO2 desorption increased with each cycle from the second to the fifth cycle. Furthermore, the CO2 desorption stabilized at a predetermined level in the fifth to tenth cycles. The CO2 desorption was closest to the predetermined level in the tenth cycle. Moreover, in the CO2 recovery treatment after the fifth cycle, the total CO2 adsorption at the end of the adsorption treatment exceeded the saturation adsorption capacity p.

[0111] Figure 25 This is a graph showing the relationship between the ratio d / b of CO2 desorption in the tenth cycle relative to the CO2 desorption in the first cycle and the ratio d / a of CO2 desorption in the tenth cycle relative to the CO2 adsorption in the first cycle, for results from the first to the ninth experiments. Figure 25 In the middle, points P1 to P9 correspond to the results of the first to ninth experiments.

[0112] Figure 25 The horizontal axis, d / b, represents the rate of change of CO2 desorption as the number of cycles increases. A larger value indicates a greater rate of increase in CO2 desorption with increasing cycle number, meaning a higher CO2 recovery effect from repeatedly performing multiple cycles of CO2 recovery processing. Conversely, a smaller value indicates a smaller rate of increase in CO2 desorption with increasing cycle number, meaning a lower CO2 recovery effect from repeatedly performing multiple cycles of CO2 recovery processing. Specifically, d / b is preferably 1.3 or higher.

[0113] Figure 25 The vertical axis, d / a, represents the absolute amount of CO2 desorbed as the number of cycles increases. A larger value means a higher CO2 recovery effect resulting from repeating the CO2 recovery process multiple times. Conversely, a smaller value means that even if the number of cycles increases due to excessively low desorption temperature, the absolute amount of CO2 desorbed is still less, resulting in a lower CO2 recovery effect from repeating the CO2 recovery process multiple times. Specifically, d / a is preferably 0.5 or higher.

[0114] like Figure 25As shown, at points P1 to P6 in the first to ninth experiments, corresponding to the first to sixth experiments (Examples 1 to 6), d / b indicates a threshold Th1 (Th1=1.3) or higher, and d / a indicates a threshold Th2 (Th2=0.5) or higher. That is, in the first to sixth experiments, a high CO2 recovery rate can be obtained with a minimal desorption temperature (i.e., without increasing energy consumption). In other words, in region A1 where d / b is above threshold Th1 and d / a is above threshold Th2, a high CO2 recovery rate can be obtained without increasing energy consumption.

[0115] In contrast, at point P7 corresponding to the seventh test (Comparative Example 1), d / a showed a value less than the threshold Th2. That is, in the seventh test, due to the excessively low desorption temperature of 60°C, the absolute amount of CO2 desorbed remained low even with an increased number of cycles, resulting in a low CO2 recovery rate. Furthermore, at points P8 and P9 corresponding to the eighth and ninth tests (Comparative Examples 2 and 3), d / b showed a value less than the threshold Th1. That is, in the eighth and ninth tests, despite sufficiently high desorption temperatures, the amount of CO2 desorbed hardly increased even after repeated cycles of CO2 recovery treatment, resulting in a low CO2 recovery rate.

[0116] Figure 26 This is a graph showing the relationship between the average CO2 residue rate (c) after CO2 desorption treatment from the first cycle to the third cycle, for results from the first to the ninth experiments, and the ratio (d / b) of the CO2 desorption amount in the tenth cycle to the CO2 desorption amount in the first cycle. Figure 26 In the diagram, the x-axis represents the average CO2 residue rate *c* after CO2 desorption treatment from the first cycle to the third cycle, and the y-axis represents the ratio *d* / b* of the CO2 desorption amount in the tenth cycle relative to the CO2 desorption amount in the first cycle. Furthermore, in... Figure 26 In the diagram, points P1 to P9 correspond to the results of the first to ninth experiments, and approximate curves for points P1 to P9 are shown.

[0117] like Figure 26As shown, when c=0, i.e., all CO2 is desorbed from the test material (CO2 adsorbent 111) in the first to third cycles, the approximate curve passes through the point (0, 1) because the amount of CO2 desorbed in the first cycle is equal to that in the tenth cycle. Furthermore, when c≈1, i.e., almost no CO2 is desorbed from the test material (CO2 adsorbent 111) in the first to third cycles, the amount of CO2 desorbed in the first cycle, b, approaches zero, resulting in a very large d / b. Therefore, the approximate curve becomes an asymptote of a straight line relative to x=1. This approximate curve is represented by the following equation (1).

[0118] [Mathematical Expression 1] The value j is any positive integer. Here, when j=0.434, the distance from each point from P1 to P9 to the approximate curve of equation (1) is minimized, and the range of x satisfying y≥1.3 is x≥0.409. That is, the range of the average CO2 residual rate c after CO2 desorption treatment from the first cycle to the third cycle, satisfying d / b≥1.3, is c≥0.409 (40.9%).

[0119] Figure 27 This is a graph showing the relationship between the average CO2 residue rate (c) after CO2 desorption treatment from the first cycle to the third cycle, for the results of the first to ninth experiments, and the ratio (d / a) of the CO2 desorption amount in the tenth cycle to the CO2 adsorption amount in the first cycle. Figure 27 In the diagram, the x-axis represents the average CO2 residue rate *c* after CO2 desorption treatment from the first cycle to the third cycle, and the y-axis represents the ratio *d* / a* of the CO2 desorption amount in the tenth cycle to the CO2 adsorption amount in the first cycle. Furthermore, in... Figure 27 In the diagram, points P1 to P9 correspond to the results of the first to ninth experiments, and approximate curves for points P1 to P9 are shown.

[0120] like Figure 27 As shown, when c=0, that is, when all CO2 is desorbed from the test material (CO2 adsorbent 111) in the first to third cycles, since the amount of CO2 desorbed in the first cycle is equal to the amount of CO2 desorbed in the tenth cycle, the approximate curve will pass through the point (0, 1) on the coordinates. Furthermore, when c=1, that is, when CO2 is not desorbed from the test material (CO2 adsorbent 111) in the first to third cycles, the amount of CO2 desorbed b in the first cycle becomes 0, and the amount of CO2 desorbed d in the tenth cycle also becomes 0, so d / b becomes 0, and therefore the approximate curve will pass through the point (1, 0) on the coordinates. This approximate curve is represented by the following equation (2).

[0121] Mathematical formula 2 The value n is any positive integer. Here, when n=3.23, the distance from each point from P1 to P9 to the approximate curve is minimized. At this time, the distance to the approximate curve position in equation (2) is minimized, and the range of x satisfying y≥0.5 is x≤0.806. That is to say, the range of the average CO2 residual rate c after CO2 desorption treatment from the first cycle to the third cycle, satisfying d / a≥0.5, is c≤0.806 (80.6%).

[0122] In summary, the CO2 recovery device 1 disclosed herein can efficiently recover CO2 at a minimum desorption temperature (i.e., without increasing energy consumption) when the average CO2 residual rate after CO2 desorption treatment from at least the first cycle to the third cycle is in the range of 40.9% to 80.6%.

[0123] <Implementation Method 2> In the first to ninth experiments, test materials without CO2 adsorption were used. In contrast, in the tenth experiment described in this embodiment, test materials pre-adsorbed with CO2 using a mixture of nitrogen and CO2 at a CO2 concentration of 2% were used. That is, in the tenth experiment, test materials pre-adsorbed with CO2 were used to perform CO2 recovery treatment after the first cycle. This will be explained in detail below.

[0124] <Experimental Conditions> In the tenth test of CO2 recovery treatment, CO2 adsorption treatment and CO2 desorption treatment were alternately repeated after a prior CO2 adsorption treatment (hereinafter referred to as pre-adsorption treatment) and a CO2 desorption treatment therefor.

[0125] First, in the pre-adsorption treatment, CO2 was adsorbed onto the first test material containing polyethyleneimine by circulating a simulated gas with a volumetric flow rate (SV) of 7.17E+4 / h for 5 minutes at a temperature set at 30°C. Here, the simulated gas used was pure nitrogen with 2% CO2 added. The amount of CO2 adsorbed was calculated based on the difference between the CO2 concentration (2%) of the simulated gas supplied to the honeycomb (CO2 adsorbent 111) and the CO2 concentration of the simulated gas passing through the honeycomb, as well as the gas flow rate. Although a HORIBA MEXA-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0126] In the CO2 desorption treatment following the pre-adsorption treatment, a reduced-pressure steam desorption process was performed. In this process, CO2 adsorbed on the test material (CO2 adsorbent 111) was desorbed by circulating 0.013 g / min of steam (by weight) through a constant-temperature bath heated to 80°C for 5 minutes. The amount of carbon dioxide desorbed was calculated based on the flow rate of the gas diluted by combining steam passing through the honeycomb with nitrogen at a flow rate of 2 L / min, and the concentration of carbon dioxide contained in the diluted gas. Although a HORIBA MEXA-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0127] In the CO2 adsorption treatment following the pre-adsorption treatment, a humidified adsorption treatment was performed. In this humidified adsorption treatment, CO2 was adsorbed onto the test material (CO2 adsorbent 111) by circulating a simulated gas with a volumetric flow rate (SV) of 2.39E+5 / h for 5 minutes at a temperature set at 30°C. Here, the simulated gas used was a gas containing 400 ppm CO2 added to pure nitrogen and humidified to a relative humidity of 60%–70%. The CO2 adsorption capacity was calculated based on the difference between the CO2 concentration (400 ppm) of the simulated gas supplied to the honeycomb (CO2 adsorbent 111) and the CO2 concentration of the simulated gas passing through the honeycomb, along with the gas flow rate. Although a HORIBA MEXA-1700D CO2 analyzer was used to measure the CO2 concentration, it was not a limitation.

[0128] <Results of the Tenth Experiment> The results of the tenth test on CO2 recovery treatment are described. In the tenth test, the first test material containing polyethyleneimine was used, and three cycles of humidified adsorption treatment and reduced-pressure steam desorption treatment were alternately repeated after pre-adsorption treatment and desorption treatment therefor. The humidified adsorption treatment and reduced-pressure steam desorption treatment after the pre-adsorption treatment in the tenth test were carried out under the same conditions as in the first test.

[0129] Figure 28 This is a graph showing the CO2 adsorption and desorption amounts in each cycle of the CO2 recovery treatment in the tenth experiment. Additionally, in... Figure 28 The figure also shows the amount of CO2 adsorbed and desorbed during the pre-adsorption treatment. Figure 29 This is a graph showing the change in total CO2 adsorption achieved through multiple cycles of CO2 recovery treatment in the results of the tenth experiment. Figure 30 A graph showing the CO2 residual rate in each cycle of the CO2 recovery treatment in the tenth experiment.

[0130] In the tenth experiment, the amount of CO2 desorbed in each cycle from the first cycle to the third cycle after pre-adsorption treatment was 0.037 g, the same as the amount of CO2 desorbed in the tenth cycle of the first experiment. Therefore, the CO2 recovery device 1 performs CO2 recovery treatment by using a CO2 adsorbent 111 pre-adsorbed with a large amount of CO2, thereby enabling efficient CO2 recovery from earlier cycles.

[0131] As described above, the CO2 recovery device 1 disclosed herein transfers a portion of the CO2 adsorbed on the CO2 adsorbent 111 to the next cycle of CO2 recovery processing in a state where a portion is not recovered but remains. Therefore, compared to a case where all CO2 adsorbed on the CO2 adsorbent 111 is recovered in one cycle of CO2 recovery processing and then transferred to the next cycle, the CO2 recovery device 1 disclosed herein can desorb and recover a sufficiently high proportion of CO2 from the CO2 adsorbent at a lower temperature in the next cycle of CO2 recovery processing. In other words, the CO2 recovery device 1 disclosed herein can efficiently recover CO2 without increasing energy consumption.

[0132] This invention is not limited to the above-described embodiments, but can be appropriately modified without departing from the spirit of the invention.

[0133] This disclosure enables the CO2 recovery device 1 to perform part or all of its processing by having a CPU (Central Processing Unit) execute a computer program.

[0134] The program described above includes a set of commands (or software code) for causing a computer to perform one or more functions described in the embodiments when read by the computer. The program may also be stored on a non-transitory computer-readable medium or a physical storage medium. As a non-limiting example, a computer-readable medium or a physical storage medium includes RAM (Random-Access Memory), ROM (Read-Only Memory), flash memory, SSD (Solid-State Drive) or other memory technologies, CD-ROM, DVD (Digital Versatile Disc), Blu-ray (registered trademark) discs or other optical disc storage, magnetic cartridges, magnetic tape, disk storage, or other magnetic storage devices. The program may also be transmitted on a temporary computer-readable medium or a communication medium. As a non-limiting example, a temporary computer-readable medium or a communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0135] This invention is not limited to the embodiments described above, but can be appropriately modified without departing from the main idea. This invention contributes to carbon neutrality, decarbonization, and the Sustainable Development Goals (SDGs).

[0136] This application claims priority based on Japanese Patent Application No. 2024-35985, filed on March 8, 2024, and all of its disclosures are incorporated herein.

[0137] Symbol Explanation 1. CO2 recovery unit; 11 CO2 adsorption section; 12. CO2 Recovery Department; 13. Measurement Department; 14. Control Department; 111 CO2 adsorbent.

Claims

1. A CO2 recovery device, comprising: The adsorption section has a CO2 adsorbent composed of an amino-containing CO2 adsorbent and a plurality of porous supports loaded with the CO2 adsorbent, and CO2 contained in a gas supplied from the outside is adsorbed onto the CO2 adsorbent. The recovery unit desorbs and recovers CO2 adsorbed on the CO2 adsorbent by adjusting the adsorption unit to a higher temperature than that used for CO2 adsorption. The CO2 recovery device alternately and repeatedly performs CO2 adsorption achieved by the adsorption unit and CO2 desorption achieved by the recovery unit. The CO2 recovery device also includes: The measuring unit measures the amount of CO2 adsorbed by the adsorption unit and the amount of CO2 desorbed by the recovery unit. The control unit controls the amount of CO2 desorption achieved by the recovery unit, such that, in cases where the adsorption of CO2 achieved by the adsorption unit and the desorption of CO2 achieved by the recovery unit are alternately repeated for three or more cycles, the average residual rate of CO2 adsorbed on the CO2 adsorbent in each of the first to third cycles is shown to be in the range of 40.9% to 80.6%.

2. The CO2 recovery device as described in claim 1, wherein, The CO2 residue rate is the ratio of the amount of CO2 adsorbed on the CO2 adsorbent after CO2 desorption achieved by the recovery unit to the amount of CO2 adsorbed on the CO2 adsorbent before CO2 desorption achieved by the recovery unit.

3. The CO2 recovery device as described in claim 1, wherein, The CO2 adsorption conditions achieved by the adsorption unit in each cycle are set to the same conditions, and the CO2 desorption conditions achieved by the recovery unit in each cycle are set to the same conditions.

4. The CO2 recovery device as described in claim 1, wherein, The adsorption of CO2 by the adsorption unit and the desorption of CO2 by the recovery unit are alternately repeated for five or more cycles.

5. The CO2 recovery device as described in claim 1, wherein, The recovery unit is further configured to desorb and recover CO2 adsorbed on the CO2 adsorbent by adjusting the adsorption unit to a lower pressure compared to the adsorption of CO2.

6. The CO2 recovery device as described in claim 1, wherein, The recovery section is further configured to desorb and recover CO2 adsorbed on the CO2 adsorbent by adjusting the adsorption section to a higher humidity level compared to the adsorption of CO2.

7. The CO2 recovery device as described in claim 1, wherein, The plurality of porous carriers have multiple pores with an average pore size of 2 nm to 200 nm and are coated on a substrate having a honeycomb shape.

8. The CO2 recovery device as described in claim 1, wherein, The plurality of porous carriers have multiple pores with an average pore size of 2 nm to 200 nm and have a particle shape.

9. The CO2 recovery device as described in claim 1, wherein, The plurality of porous carriers use either silicon dioxide or aluminum oxide as the main component.

10. The CO2 recovery device as described in claim 1, wherein, The CO2 adsorbent is a polyamine or an amino-containing compound containing the polyamine, wherein the polyamine comprises any one of polyethyleneimine, methylated polyethyleneimine, isopropylated polyethyleneimine, polyallylamine, pentaethylenehexamine, methylated pentaethylenehexamine, isopropylated pentaethylenehexamine, tetraethylenepentamine, methylated tetraethylenepentamine, and isopropylated tetraethylenepentamine.

11. A CO2 recovery method, wherein the CO2 recovery is achieved by a CO2 recovery device, wherein, The CO2 recovery device includes: The adsorption section has a CO2 adsorbent composed of an amino-containing CO2 adsorbent and a plurality of porous supports loaded with the CO2 adsorbent, and CO2 contained in a gas supplied from the outside is adsorbed onto the CO2 adsorbent. The recovery unit desorbs and recovers CO2 adsorbed on the CO2 adsorbent by adjusting the adsorption unit to a higher temperature than that used for CO2 adsorption. The CO2 recovery device alternately and repeatedly performs CO2 adsorption achieved by the adsorption unit and CO2 desorption achieved by the recovery unit. In the CO2 recovery method, The amount of CO2 desorbed by the recovery unit is controlled such that, in cases where the adsorption of CO2 by the adsorption unit and the desorption of CO2 by the recovery unit are alternately repeated for three or more cycles, the average residual rate of CO2 adsorbed on the CO2 adsorbent in each of the first to third cycles is shown to be in the range of 40.9% to 80.6%.

12. A control program that causes a computer to perform CO2 recovery processing carried out by a CO2 recovery device, wherein, The CO2 recovery device includes: The adsorption section has a CO2 adsorbent composed of an amino-containing CO2 adsorbent and a plurality of porous supports loaded with the CO2 adsorbent, and CO2 contained in a gas supplied from the outside is adsorbed onto the CO2 adsorbent. The recovery unit desorbs and recovers CO2 adsorbed on the CO2 adsorbent by adjusting the adsorption unit to a higher temperature than that used for CO2 adsorption. The CO2 recovery device alternately and repeatedly performs CO2 adsorption achieved by the adsorption unit and CO2 desorption achieved by the recovery unit. The control program causes the computer to perform the following processes: The process involves measuring the amount of CO2 adsorbed by the adsorption unit and the amount of CO2 desorbed by the recovery unit. The amount of CO2 desorbed by the recovery unit is controlled such that, in cases where the adsorption of CO2 by the adsorption unit and the desorption of CO2 by the recovery unit are alternately repeated for three or more cycles, the average residual rate of CO2 adsorbed on the CO2 adsorbent in each of the first to third cycles is shown to be in the range of 40.9% to 80.6%.

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