Co2 recovery absorber and co2 recovery device

Abstract

This CO2 recovery absorber is formed by bundling a plurality of rod-shaped rubbers having a thickness of 0.5 mm-10 mm inclusive. This CO2 recovery device includes a chamber in which at least a gas inlet, a gas absorption / desorption part, and a gas outlet are arranged in series, and the gas absorption / desorption part is provided with said CO2 recovery absorber.

Description

CO2 capture absorbent material and CO2 capture device

[0001] The present invention is ２ Recovery absorbent and CO ２ Regarding recovery devices.

[0002] From the perspective of reducing greenhouse gas emissions, taking into account desorption energy efficiency, ２ Low-energy CO2-containing combustion gas, natural gas, and biogas ２ There is a strong desire to separate and recover these substances.

[0003] CO ２ In the case of medium concentration gases with a concentration of 5 to 20%, CO ２ A method using molten potassium carbonate was adopted as a CO separation and recovery method. However, this method often caused problems with corrosion of steel materials. Therefore, this method is being replaced by the AGR (Acid Gas Removal) process using an amine solvent. Amine solvents have the advantage that the absorbent can be regenerated by heat and the equipment maintenance is easy. On the other hand, the AGR process ２ When the concentration exceeds 30%, a large amount of heat energy is required to regenerate the amine solvent, and the necessary equipment becomes huge. ２ In situations where the concentration exceeds 30%, a method using an organic solvent such as propylene carbonate (PC) as an absorbent is used. ２ However, the method of recovering CO2 has the problem of a large energy loss because it is necessary to dissolve the mixed gas in high-pressure microbubbles, and the cost of recovering the organic solvent is also required because part of the organic solvent volatilizes. Furthermore, the method of using this organic solvent as an absorbent also has the problem of requiring huge equipment. ２ Separation technology was highly anticipated.

[0004] In this situation, new CO ２As a recovery method, a method using rubber as an absorbent has attracted attention. For example, Non-Patent Document 1 discloses a method using rubber as an absorbent. This method using rubber as an absorbent is ２ It has been reported that it has the excellent characteristics of high absorption / desorption efficiency and low energy loss even at high concentrations.

[0005] Izumi Ichinose et al., JACI GSC Symposium (June 15-16, 2022)

[0006] When using a solid such as rubber as an absorbent, powder is often used to increase the surface area in contact with the gas. However, with powder, it is difficult to increase the powder packing rate while maintaining a laminar flow of gas flowing around the powder. Powder also has excellent initial absorption properties, but is prone to deterioration over time. Furthermore, powder is difficult to maintain and tends to contaminate the inside of the device, requiring frequent cleaning.

[0007] In view of the above background, the object of the present invention is to provide a high-concentration CO ２ Efficient and low-energy CO2 reduction from combustion gases, natural gas, biogas, etc. ２ This CO2 separator is easy to maintain and reduces system downtime. ２ Recovery absorbent and CO ２ The object is to provide a recovery device.

[0008] The configurations of the present invention are as follows: (Configuration 1) A CO2 compressor including a plurality of rubbers, each of which has a rod shape and a thickness of 0.5 mm to 10 mm, and which is arranged in a bundle. ２ (Configuration 2) The CO absorbing material according to Configuration 1, wherein the rubber has a hollow tubular shape. ２ (Configuration 3) The CO absorbing material according to Configuration 1, wherein the rubber has a cylindrical shape. ２ (Configuration 4) The CO absorbing material according to any one of Configurations 1 to 3, wherein the rubber is one or more selected from the group consisting of silicone rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, and urethane rubber. ２(Configuration 5) The CO2 recovery absorbent material according to any one of Configurations 1 to 4, wherein a gap is disposed between two adjacent rubber pieces among the plurality of rubber pieces, through which gas flows from one side to the other side in the longitudinal direction of the two rubber pieces. ２ (Configuration 6) The CO absorbing material according to any one of Configurations 1 to 5, wherein the rubber has a groove formed therein from one end to the other end in the longitudinal direction. ２ (Configuration 7) The CO absorbing material according to any one of Configurations 1 to 6, wherein a spacer is disposed between two adjacent rubber pieces among the plurality of rubber pieces. ２ (Configuration 8) The CO absorbing material according to any one of Configurations 1 to 7, wherein the material is placed in a hollow jig, and the jig has openings formed at one end and the other end of the plurality of rubber members in the longitudinal direction. ２ (Configuration 9) A CO2 recovery absorbent having a chamber in which at least a gas inlet, a gas absorption / desorption section, and a gas outlet are arranged in series. ２ 9. A CO recovery device, wherein the gas absorption / desorption unit is ２ A recovery absorbent is provided. ２ (Configuration 10) The CO recovery device according to Configuration 9, wherein a compressor is connected to the gas inlet via an on-off valve. ２ (Configuration 11) The CO recovery device according to Configuration 9 or 10, wherein a compressor is connected to the gas outlet via an on-off valve. ２ Recovery device.

[0009] According to the present invention, CO ２ CO2 can be efficiently produced using low energy from gases containing CO, such as combustion gas, natural gas, and biogas. ２ CO can be separated and collected, and maintenance is easy. ２ Absorbent material for recovery and CO2 absorbent material ２ A recovery device is provided.

[0010] CO ２ 1 is an explanatory diagram showing the state in which the recovery absorbent material is placed in the absorption tower. ２ FIG. 1 is an explanatory diagram showing the shape of a recovery absorbent material. ２FIG. 1 is an explanatory diagram showing the shape of a recovery absorbent material. ２ 1 is an explanatory diagram showing the arrangement of the recovery absorbent material. ２ FIG. 1 is a diagram showing the configuration of a recovery device. ２ 1 is a characteristic diagram showing the absorption characteristics (breakthrough characteristics) of CO ２ 10 is a characteristic diagram showing the absorption characteristics (pressure change characteristics) of the

[0011] Hereinafter, the CO ２ Recovery absorbent and CO ２ The recovery device will be explained using the drawings.

[0012] <Configuration> CO according to this embodiment ２ As shown in FIG. 1, the recovery absorbent material 100 ２ The recovery device includes a plurality of rubber pieces 16 that are used while being housed in an absorption tower 12 (an example of a "jig"). Specifically, each of the plurality of rubber pieces 16 is rod-shaped. In other words, each rubber piece 16 is long. FIG. 1 illustrates the x direction in which each rubber piece 16 extends. The plurality of rubber pieces 16 are bundled together. That is, the CO ２ The recovery absorbent material 100 is an absorbent material in which a plurality of rubber members 16 are arranged in a bundle. ２ The number of rubber pieces 16 provided in the recovery absorbent material 100 is not particularly limited, but is expected to be, for example, 3 to 300,000 pieces.

[0013] CO ２ The gas to be treated by the recovery absorbent 100 is CO ２ It can handle all gases that contain CO. It is a gas that is mixed with methane, which is assumed to be biogas, and 30 to 50 mol% CO. ２ and nitrogen gas (N ２ ) with 5 to 15 mol% CO ２ In view of the environment in which these gases are placed, methane in particular contains CO that is easily liquefied in the gas to be treated. ２ In this state, CO can be efficiently separated by cryogenic separation methods. ２To separate CO, low-temperature treatment below -60°C is required. ２ The energy efficiency of separation and recovery is significantly reduced. Furthermore, even if treatment is performed at such low temperatures, it is not easy to increase the purity of methane or nitrogen gas. On the other hand, the method of the present invention can be performed at a low temperature of -60°C or higher, and is a method that can sufficiently reduce energy consumption. ２ ) with 5 to 50 mol% CO ２ In the case of gas containing CO ２ Although the amount of CO2 varies, the same concept as when CO2 is mixed into methane gas can be applied.

[0014] The absorber tower 12 is hollow inside. Like each rubber piece 16, the absorber tower 12 of this embodiment has an elongated shape extending in the x direction. In other words, the x direction is an example of the longitudinal direction of the rubber piece 16 and the longitudinal direction of the absorber tower 12. A pipe 17a communicating with the inside of the absorber tower 12 is provided at one end (the end on the negative side in the x direction) of the absorber tower 12. A pipe 17b communicating with the inside of the absorber tower 12 is provided at the other end (the end on the positive side in the x direction) of the absorber tower 12. That is, an opening is formed at each of the one end side and the other end side of the absorber tower 12 in the x direction. Specifically, an opening (an example of a "gas inlet") for connection to pipe 17a is formed at one end side in the x direction of absorber 12 (negative side in the x direction), and an opening (an example of a "gas outlet") for connection to pipe 17b is formed at the other end side in the x direction of absorber 12 (positive side in the x direction). The internal space of absorber 12 (an example of a "chamber") is an example of a "gas absorption / desorption section". Pipe 17a is an example of a pipe for supplying the gas to be treated into absorber 12, and pipe 17b is an example of a pipe for supplying the CO ２ This is an example of a pipe for discharging the treated gas from the inside of the absorber 12. Note that the maintenance pipe 17c may be arranged on the side of the absorber 12 to improve maintainability.

[0015] As described above, a plurality of rubber pieces 16 are housed inside the absorption tower 12. Here, as illustrated in FIG. 2( a), each rubber piece 16 is preferably a columnar rubber piece 16a. FIG. 2( a) illustrates a case where the columnar rubber piece 16a is cylindrical. Alternatively, as illustrated in FIG. 2( b), each rubber piece 16 is preferably a hollow tubular rubber piece 16b. In other words, the tubular rubber piece 16b has through holes along the x direction. Gas can pass through the inside of the tubular rubber piece 16b. FIG. 2( b) illustrates a case where the tubular rubber piece 16b is cylindrical.

[0016] The rubber 16 is preferably arranged so that the longitudinal direction of the rubber 16 is aligned with the longitudinal direction of the absorber 12. In particular, the tubular rubber 16b is in frequent contact with the gas flowing around it, and as a result, a large amount of CO ２ On the other hand, the columnar rubber 16a has the advantage that it is easy to keep costs down and to maintain.

[0017] 3, a groove G may be formed in the rubber 16 (16a, 16b) from one end to the other in the longitudinal direction. A plurality of grooves G may be formed on the outer circumferential surface of the rubber 16. By forming the groove G, the amount and speed of the airflow can be increased while ensuring the contact area between the rubber and the airflow.

[0018] As illustrated in FIG. 4 , two adjacent pieces of rubber 16 among the plurality of rubbers 16 are preferably spaced apart from each other with a gap 19 between them so as not to contact each other and to ensure a flow path through which gas flows in a laminar flow. The gap 19 is provided over the entire length of the two adjacent pieces of rubber 16. That is, the gap 19 is provided in an elongated shape along the x direction, and is a space through which gas flows from the negative side to the positive side in the x direction. The distance of the gap 19 is expected to be, for example, 0.01 to 0.5 cm. The distance of the gap 19 is the shortest distance between the outer peripheral surface of one of the two adjacent pieces of rubber 16 and the outer peripheral surface of the other rubber 16. The gap 19 may be provided using a jig 18 such as a spacer.

[0019] The effects of forming the rubber 16 in a rod shape include the following: First, it becomes easier to ensure a laminar gas flow path. Therefore, the filling rate of the absorbent material can be increased, and highly efficient CO ２ The advantages of this method include gas absorption and desorption. Because of the stable laminar flow, there is little instability associated with swelling of the rubber 16, resulting in consistently stable separation efficiency. Second, the rod-shaped rubber 16 exhibits little change over time, resulting in high absorption and desorption efficiency over a long period of time. On the other hand, when powdered absorbents, which are commonly used in conventional methods, are used, the initial absorption and desorption efficiency is high, but changes significantly over time, resulting in a relatively rapid decline in absorption and desorption efficiency. Third, the rod-shaped rubber 16 is easy to maintain, allowing the absorbent to be replaced easily and quickly, and the replacement frequency is low. Furthermore, there is little contamination inside the device due to rubber replacement or deterioration over time, and there is little downtime for cleaning, etc. Rubber is generally characterized by its elasticity, flexibility, and tenacity, and is resistant to breakage and damage even when thin. As described above, the rubber 16 according to this embodiment is a long piece of rubber. However, unlike porous ceramics and the like, the mechanical properties of rubber are utilized, resulting in easy maintenance, resistance to breakage, and reduced dust generation. In fact, the method of the present invention can halve the frequency of rubber replacement compared to when powdered rubber is used, and also eliminates the need for cleaning inside the device, which was necessary when powdered rubber was used.

[0020] The cross-sectional shape of the rubber 16 is not particularly limited, and examples include a circle, an ellipse, and a polygon. The cross-sectional shape of the rubber 16 is the shape formed by the periphery of the cross section in a plane perpendicular to the x-direction. When a plurality of rubbers 16 are arranged in a bundle, the cross-sectional shape of the rubber 16 is not particularly limited as long as a flow path (hereinafter referred to as a "gas flow path") through which gas flows in a laminar flow is formed.

[0021] Furthermore, as long as a gas flow path is formed when multiple rubber members 16 are arranged in a bundle, it is not necessary to arrange the adjacent rubber members 16 so that they do not come into contact with each other. In other words, it is sufficient that a gas flow path is formed even if the rubber members 16 are partially in contact with each other. For example, in the case of cylindrical rubber member 16a, even if adjacent rubber members 16 are arranged so that they come into contact with each other, as illustrated in FIG. 2(a), gaps are formed between the rubber members 16, and these gaps form gas flow paths. In addition, in the case of tubular rubber member 16, the through-holes (hollow portions) of the rubber member 16 itself also function as gas flow paths. Furthermore, the grooves G formed in the rubber member 16 in FIG. 3 also function as gas flow paths. Note that the gas flow path is a flow path along the x-direction and is a space that penetrates from the negative side to the positive side of the x-direction.

[0022] As can be understood from the above explanation, it is assumed that the gas flow path is formed by, for example, setting the cross-sectional shape of the rubber 16, arranging a plurality of rubbers 16, forming the rubber 16 into a tubular shape, and one or more of the grooves G. However, the gas flow path is not limited to the above examples, and is not limited to any path that allows gas to flow while retaining it in the internal space of the absorption tower 12. By providing the gas flow path, it is possible to increase the packing rate of the absorbent while ensuring a laminar gas flow path, and to achieve highly efficient CO ２ The rubber 16 having a circular cross section (16a, 16b in FIG. 2) has the advantage that it is easier to arrange and maintain uniformity of each gas flow path compared to rubber 16 having a cross section other than a circle.

[0023] The thickness of the rubber 16 is 0.5 mm or more and 10 mm or less. When the thickness of the rubber 16 is within the above range, CO 2 is absorbed into the rubber from the gas flowing along the rubber 16 with sufficient efficiency. ２ If the thickness of the rubber 16 exceeds 10 mm, CO ２ Diffuse CO ２ If the thickness of the rubber is less than 0.5 mm, the rubber will not be able to stand upright due to insufficient rigidity, and maintenance will be impaired. From these viewpoints, the thickness of the rubber is more preferably 1 mm or more and 5 mm or less.

[0024] In the case of columnar rubber 16a, the thickness of rubber 16 refers to the width of the cross-sectional shape in a plane perpendicular to the longitudinal direction (x direction) of rubber 16. Here, the width of the cross-sectional shape refers to the length of the shortest line segment that passes through the center of the cross-sectional shape and connects two points on the periphery of the cross-sectional shape. Therefore, for example, in the case of cylindrical rubber 16a, the thickness of rubber 16 is the diameter, and in the case of elliptical cylindrical rubber 16a, the thickness of rubber 16 is the length of the minor axis.

[0025] On the other hand, in the case of tubular rubber 16b, the thickness of rubber 16 is the wall thickness (the length between the outer peripheral surface and the inner peripheral surface). Therefore, for example, in the case of cylindrical rubber 16b, the thickness of rubber 16 is the wall thickness ((outer diameter - inner diameter) / 2). Note that, if grooves G are formed in rubber 16, the thickness is the thickness of the portion of rubber 16 where the grooves G are not formed. The length of rubber 16 is not particularly limited, but is assumed to be, for example, 40 to 2000 cm. In the case of tubular rubber 16b, from the viewpoint of ensuring a sufficient gas flow path, the cross-sectional area of ​​the through-hole (hollow portion) is, for example, 0.005 to 0.5 cm ２ It is preferable that:

[0026] The spacing between adjacent rubber members 16 is preferably adjusted so that the packing rate of the rubber members 16 is 40% by volume or more and 90% by volume or less in the absorption tower 12. When the packing rate is within the above range, a sufficient amount of absorbent material is secured while the gas flow along the rubber members 16 becomes a laminar flow, and as a result, the rubber members can absorb CO with high efficiency. ２ From the above viewpoint, the filling rate of the rubber 16 in the absorber 12 is more preferably 60% by volume or more and 85% by volume or less.

[0027] CO ２ The rubber used as the recovery absorbent is one or more rubbers selected from the group consisting of silicone rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, and urethane rubber, and silicone rubber is particularly preferred. Silicone rubber has a large market, is inexpensive, and many tubular and cylindrical products are sold. It is easy to process, and it is a CO ２It has the characteristics of absorbing a large amount of water, having a high absorption / desorption rate, and being highly durable.

[0028] A crosslinked product of PDMS (PolyDiMethylSiloxane), a type of silicone rubber, is particularly preferred. The crosslinking method preferably uses a radical crosslinking agent or a method in which multiple vinyl groups in the molecules of both PDMS are crosslinked by hydrosilation. The latter method usually uses a platinum catalyst. Furthermore, considering the cost and resource recycling, CO ２ It is also preferable to use recycled rubber such as scrap tires as the rubber for the recovered absorbent material. The glass transition temperature of the rubber is preferably −150° C. or higher and −10° C. or lower. The SP value of the rubber at room temperature is 7.0 (cal / cm ３ ) ０．５ More than 10.0 (cal / cm ３ ) ０．５ The elastic modulus of the rubber at 25°C is preferably 0.03 MPa or more and 8 MPa or less. Rubbers meeting these conditions have high CO ２ It has absorption amount and absorption / desorption efficiency.

[0029] The glass transition temperature can be determined by dynamic viscoelasticity measurement. The SP value at room temperature (25°C) can be determined from various databases. The elastic modulus at 25°C can be determined by a tensile test.

[0030] The SP value at room temperature is 10.5 (cal / cm ３ ) ０．５ The following rubbers are generally hydrophobic, but some of them are prone to absorbing water. In such cases, making the rubber hydrophobic allows CO ２ At temperatures below freezing, water is easily absorbed into the rubber's interface and voids, and even a small amount of water can easily reduce the absorption capacity. In such cases, it is a good idea to have the rubber absorb hydrophobic molecules such as decane. This will suppress water absorption and reduce CO ２ The contact angle of water on the surface of the rubber absorbent material is sufficient if it is 80° or more and 150° or less. The SP value of the rubber at room temperature is ２ It is important that the SP value is close to that of CO２ It is known that the SP value of rubber increases with decreasing temperature. The SP value of rubber also increases with decreasing temperature, but the increase in the SP value of PDMS rubber is due to the CO ２ Therefore, in the range of -20°C to -40°C, rubbers with a slightly larger SP value than PDMS rubber are preferably used. Examples of such rubbers include those in which the methyl groups in the PDMS rubber molecule are replaced with phenyl groups or the like. Here, the CO ２ The desorption of can be achieved by reducing the pressure, and does not require heating, which means that it consumes little energy.

[0031] As shown in FIG. ２ In order to improve the absorption amount and separation efficiency, it is also preferable to use a plurality of (three in FIG. 5) absorption towers 12_1, 12_2, and 12_3 connected in series.

[0032] CO ２ As shown in Fig. 6, an example of the configuration of the recovery device 1 includes at least one pair of absorption towers 12a and 12b, two in total. Each of the absorption towers 12a and 12b is controlled by a temperature control unit 11 to adjust the CO ２ The temperature is controlled according to the absorption and separation process.

[0033] The absorption towers 12a and 12b are connected to switching valves 13, 14 and 15. ２ The switching valve 13 is connected to the treated gas pipe 3 via an on-off valve 31. The switching valve 14 is connected to the treated gas pipe 3 via a valve 41. ２ The recovery pipe 4 is connected to the switching valve 15. The CO ２ The treated gas pipe 3 is connected to a treated gas discharge pipe 7. The treated gas pipe 3 is a pipe for supplying the treated gas to an absorption tower 12. ２ The recovery pipe 4 is ２ High concentration CO absorbed in the recovery absorbent ２ This is a pipe for recovering CO ２ The treated gas discharge pipe 7 discharges CO ２This is a pipe for discharging gas after it has been absorbed.

[0034] The gas to be treated supplied from the gas to be treated pipe 3 is introduced into either the absorption tower 12a or 12b by switching through the compressor 32, the on-off valve 31 and the switching valve 13. By switching the switching valves 13, 14 and 15, one of the absorption towers 12a and 12b is turned into a CO ２ Absorption operation, the other CO ２ This will be a detached operation.

[0035] CO ２ A specific example of the absorption / desorption method is as follows: The switching valve 13 is opened to the absorber 12a side and closed to the absorber 12b side, the switching valve 14 is closed to the absorber 12a side and opened to the absorber 12b side, and the switching valve 15 is opened to the absorber 12a side and closed to the absorber 12b side, so that the absorber 12a is supplied with CO ２ Absorption operation, absorption tower 12b is CO ２ Thereafter, the switching valve 13 is closed to the absorber 12a side and opened to the absorber 12b side, the switching valve 14 is opened to the absorber 12a side and closed to the absorber 12b side, and the switching valve 15 is closed to the absorber 12a side and opened to the absorber 12b side, so that the absorber 12a is in CO ２ Desorption operation, absorption tower 12b is CO ２ This process is then repeated to ２ Here, the absorption and desorption are controlled by pressure. The absorption tower 12a or 12b is insulated, but it is preferable to use a temperature control means 11 for pre-cooling and maintaining a low temperature. Here, the temperature inside the absorption tower 12 during absorption is preferably −60° C. or higher and 0° C. or lower, and more preferably −40° C. or higher and −20° C. or lower. By controlling the temperature inside the absorption tower 12 within this range, it is possible to reduce the CO 2 during desorption. ２ This can prevent solidification of the mixture, thereby improving separation efficiency.

[0036] The switching of the absorption and desorption of the absorber 12a and 12b (switching of the valves 13, 14, and 15) is performed to ２ It is preferable to do this based on the gas breakthrough time characteristics. ２ Concentration (C / C０ It is preferable to switch the valves at the timing when the temperature rises, and switch between absorption and desorption in the absorption towers 12a and 12b. By switching between absorption and desorption at this timing, the absorption and desorption efficiency can be maximized. ０ is CO ２ represents the initial concentration.

[0037] CO in the absorption towers 12a and 12b ２ The pressure during absorption is preferably adjusted to 1 MPa or more and 10 MPa or less. ２ The absorption amount depends on the pressure, and the higher the pressure, the greater the absorption amount. Below 1 MPa, the absorption amount is small and CO ２ This is not very preferable from the viewpoint of absorption efficiency. On the other hand, if the pressure exceeds 10 MPa, it becomes difficult to maintain the pressure resistance of the absorption tower.

[0038] The gas desorbed from the absorption tower 12a or 12b is a low CO ２ The treated gas (CO ２ Treated gas) and higher CO ２ High concentration of CO ２ CO ２ The treated gas is discharged through the on-off valve 71 and the CO ２ Treated gas exhaust pipe 7 ２ The treated gas is discharged from the treated gas discharge facility. ２ It is preferable to provide a check valve 72 in the treated gas exhaust pipe 7 to prevent backflow and adjust the flow rate. The check valve 72 can prevent gas from flowing in from the outside and also can prevent CO ２ The pressure of the gas in the treated gas discharge pipe 7 is ２ The flow rate can be adjusted so that it is slightly lower than the pressure during absorption, ensuring the gas residence time in the absorption tower. ２ Treated gas (CO ２ The removed gas) is CO ２Because the concentration of CO2 is low, the gas does not freeze and clog pipes, even in polar regions, and can be delivered to consumption areas via pipelines.

[0039] Here, the CO in the gas introduced into the absorption towers 12a and 12b ２ The concentration of CO in the gas to be treated ２ The concentration is 5 mol% or more and 50 mol% or less, but CO ２ CO emitted from treated gas discharge facility ２ The concentration is preferably adjusted to 2 mol% or more and 10 mol% or less. When the concentration is adjusted to this range, corrosion prevention effect can be obtained when transporting through a pipeline. ２ CO emitted from treated gas discharge facility ２ The concentration is preferably adjusted to 0.5 mol % or more and 2 mol % or less. When the concentration is adjusted to this range, a large greenhouse gas reduction effect can be obtained in the case of nitrogen gas, and the range of industrial use can be expanded in the case of methane gas.

[0040] High concentration CO ２ The gas is supplied through an on-off valve 41 and a high-concentration CO ２ Gas exhaust equipment (compressor) 42 and high concentration CO ２ Treatment is carried out through the gas recovery pipe 4. High concentration CO ２ Gas CO ２ The concentration of CO is preferably 40 mol % or more and 80 mol % or less. ２ This adjustment of the concentration improves the efficiency of the separation system. ２ It can be adjusted by adjusting the temperature and pressure during absorption. After conducting various experiments, it was found that the breakthrough time per absorber (12) is between 5 and 60 minutes. ２ This was optimal for improving the absorption amount and absorption / desorption efficiency.

[0041] CO2 absorber using rubber ２ The separation system is ２ This method is characterized by the fact that it can separate the above compounds, and that the energy required for separation is small due to the chemical absorption method using an amine solvent.

[0042] Using the equipment of this embodiment, CO ２ When a mixed gas containing nitrogen at a concentration of approximately 30 mol% was treated, CO was efficiently produced with low energy consumption. ２ CO ２ It was confirmed that nitrogen gas with a CO content of 2% or less could be efficiently obtained. ２ The separation system is a methane / CO ２ Since it can also be applied to mixed gases, it can be said that it will make it possible to transport natural gas extracted in polar regions by pipeline. Biogas also generally contains high concentrations of CO ２ Since it contains ２ Separation systems are also useful for treating biogas.

[0043] The rod-shaped rubber of the present invention is ２ CO used as a capture absorbent ２ The recovery equipment alone has high CO ２ The recovery rate of CO ２ In addition to capture devices, other methods, such as CO2 capture using strong absorbents or adsorbents such as alkaline salts or activated carbon, ２ Recovery equipment or CO ２ It is also preferable to use a cryogenic separation device connected in tandem or cyclically. ２ It is used as an absorbent for recovery, and these CO ２ The capture absorbent is surrounded by a desired gas, such as high-pressure gaseous methane. ２ When gas is discharged, the desired gas is also discharged, and if this gas is discarded, it will lead to a loss of the desired gas. ２ CO from gas using cryogenic separation method ２ Liquid CO ２ Methane / CO that is not liquefied after separation as ２ The mixed gas is treated with the CO ２ Circulation back into the separation system is preferred.

[0044] Here, 105 g of cylindrical silicone rods made of PDMS with a diameter of 2 mm and a length of 400 mm were bundled and placed in the absorption tower at a packing rate of 66%. ２ , 30% CO ２ A gas consisting of the above was flowed at a flow rate of 192 sccm to examine the breakthrough characteristics. The results are shown in Figure 7. The temperature was -30°C. The results of monitoring the pressure on the inside and outside are shown in Figure 8. No significant difference in pressure was observed between the inside and outside, and the pressure decreased linearly until the breakthrough characteristics began to saturate, indicating that the saturation characteristics were observed.

[0045] According to the present invention, CO ２ Efficiently convert CO2-containing combustion gases, natural gas, biogas, etc. ２ This makes it possible to remove, for example, CO ２ Therefore, it is possible to process natural gas containing uranium at low cost. In this way, the present invention makes it possible to effectively utilize gases that have been difficult to utilize until now, and is believed to greatly contribute to the development of industry and society.

[0046] 1:CO ２ Recovery device (absorption / separation device) 3: Treated gas supply pipe 4: High concentration CO ２ Recovery pipe 7: CO ２ Treated gas exhaust pipe 11: Temperature control means 12: CO ２ Recovery device (absorption tower) 12a: CO ２ Recovery device (absorption tower) 12b: CO ２ Recovery device (absorption tower) 12_1: CO ２ Recovery device (absorption tower) 12_2: CO ２ Recovery device (absorption tower) 12_3: CO ２ Recovery device (absorption tower) 13: Switching valve 14: Switching valve 15: Switching valve 16: Rubber 16a: Rod-shaped rubber (cylindrical) 16b: Rod-shaped rubber (tube-shaped) 17a: Pipe 17b: Pipe 17c: Pipe 18: Spacer (jig) 19: Space 31: Opening / closing valve 32: Compressor 41: Opening / closing valve 42: High-concentration CO ２ Gas exhaust equipment (compressor) 71: Opening and closing valve 72: Check valve with flow rate adjustment function

Claims

1. A CO recovery absorbent comprising a plurality of rubbers, wherein the shape of the rubber is rod-shaped, the thickness of the rubber is 0.5 mm or more and 10 mm or less, and the plurality of rubbers are arranged in a bundle. ２ Recovery absorbent.

2. The shape of the rubber is a tubular shape that is hollow, and the CO according to claim 1 ２ Absorbent material for recovery.

3. The shape of the rubber is cylindrical, and the CO according to claim 1 ２ Absorbent material for recovery.

4. The rubber is composed of one or more selected from the group consisting of silicone rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, and urethane rubber, and the CO according to any one of claims 1 to 3 ２ Absorbent for recovery 5. In the plurality of rubbers, a gap through which gas flows from one side to the other side in the longitudinal direction of the two adjacent rubbers is arranged between the two adjacent rubbers. The CO recovery absorbent according to any one of claims 1 to 4 ２ recovery absorbent 6. The CO recovery absorbent according to any one of claims 1 to 5, wherein a groove is formed in the rubber from one end in the longitudinal direction to the other end. ２ Absorbent for recovery.

7. In the plurality of rubbers, a spacer is disposed between two adjacent rubbers. The CO according to any one of claims 1 to 6 ２ Absorbent material for recovery 8. The CO according to any one of claims 1 to 7, which is disposed inside a jig having a hollow interior, and openings are respectively formed at one end side and the other end side in the longitudinal direction of the plurality of rubbers in the jig. ２ Absorbent material for recovery.

9. A CO recovery device comprising a chamber in which at least a gas inlet, a gas absorption and desorption section, and a gas outlet are arranged in series. ２ The gas absorption and desorption section is provided with the CO absorption material for recovery according to any one of claims 1 to 8. ２ Recovery device, in which the absorption material for CO recovery is arranged. ２ Recovery device.

10. The CO recovery device according to claim 9, wherein a compressor is connected to the gas inlet via an on-off valve. ２ recovery device.

11. The CO recovery device according to claim 9 or 10, wherein a compressor is connected to the gas outlet via an on-off valve. ２ recovery device.

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