Gas recovery device

Abstract

The problem to be solved by the present invention is to provide a module-aggregated gas recovery device which has a plurality of adsorption modules, is not individually provided with dedicated fans corresponding to the respective adsorption modules, and can reduce the work of the fans, thereby reducing the energy for gas adsorption operation. In order to solve the problem, a carbon dioxide recovery device (1) is provided with: a plurality of modules (11) that execute an adsorption step and a desorption step; and fans (61), the number of which is smaller than the number of the modules (11), and which supply gas to the inside of the plurality of modules (11). Furthermore, each of the plurality of modules (11) is provided with a third valve (23) and a fourth valve (24) at a gas inlet and a gas outlet, respectively, and the valve opening degree of the fourth valve (24) changes according to the carbon dioxide adsorption progress of the module (11) provided with the fourth valve (24).

Description

Technical Field

[0001] The present disclosure relates to a gas recovery device. Background Art

[0002] Conventionally, as a gas recovery device, for example, a technique for recovering carbon dioxide from a gas containing carbon dioxide such as the atmosphere is known. As a document describing such a technique, for example, there is Patent Document 1. In Patent Document 1, a carbon dioxide recovery and release device is described, which includes a blower unit for sucking and transporting external gas to an adsorption unit.

[0003] In the adsorption process, as adsorption is carried out using an adsorbent, the gas adsorption capacity (gas absorption rate) of the adsorbent gradually decreases. In the initial stage of the adsorption process, a large amount of gas can be adsorbed. Therefore, it is ideal to bring a large amount of atmosphere into contact with the adsorbent. However, in the final stage of the adsorption process, it is not necessary to bring a large amount of atmosphere into contact with the adsorbent.

[0004] In Patent Document 1, an adsorption unit (adsorption module) including an adsorbent and a blower unit are arranged one-to-one. In the adsorption process, blowing is required. On the other hand, in the desorption process, blowing is not required. Therefore, the fan of the blower unit can also be stopped. However, a large amount of power is required when the fan is started, and repeated starting and stopping easily cause fan failure.

[0005] In addition, it can be considered to be configured with multiple adsorption modules, and adsorption and desorption are carried out in sequence at staggered time intervals, so as to perform gas adsorption more efficiently. In this case, if it is configured with multiple adsorption modules and adsorption and desorption are carried out in sequence at staggered time intervals, and the gas blowing in each adsorption module is concentrated by one fan, the fan can be continuously driven while performing gas recovery more efficiently.

[0006] For example, when the ratio of the time length ta of the adsorption step in which air flows through the adsorption module during the gas adsorption step, to the total time length td of the preheating step and the desorption step for gas desorption, and the cooling step for adsorption preparation, etc., which are independent of air flow, takes a value such as ta:td = 7:1, the following configuration can be set: taking 7 adsorption modules + 1 desorption module = 8 modules as a group, and setting a positive multiple of this group as a unit of the gas recovery device. In this case, for example, for a group of 8 modules, the step time of each module is delayed by (ta + td) / 8 in sequence, so that adsorption is completed in sequence, and thus the desorption step is carried out in sequence. Thereby, the desorption step can always be performed by a module somewhere, and thus efficient thermal management can be carried out.

[0007] [Prior Art Documents]

[0008] (Patent Document)

[0009] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-98220 Summary of the Invention

[0010] [Problems to be Solved by the Invention]

[0011] However, when multiple adsorption modules are configured and a single fan is used for air supply, even if the required air supply volumes of the multiple adsorption modules are different, the fan needs to be driven in the state with the highest required air volume. Therefore, there is a concern that the energy consumption of the fan will increase.

[0012] An object of the present disclosure is to provide a gas recovery device, which is a modular gas recovery device having multiple adsorption modules and not individually provided with dedicated fans corresponding to the respective adsorption modules, capable of reducing the work done by the fans and thereby reducing the energy used for gas adsorption operation.

[0013] [Technical Means for Solving the Problems]

[0014] The present disclosure solves the above problems by the following means. In addition, for easy understanding, reference numerals corresponding to the embodiments of the present disclosure are attached for explanation, but it is not limited thereto.

[0015] A first disclosure is a gas recovery device (1), comprising: a plurality of modules (11) having an adsorbent material (12) therein and performing an adsorption process and a desorption process, the adsorption process being to suck a gas containing a gas to be recovered and cause the adsorbent material (12) to adsorb the gas to be recovered, and the desorption process being to cause the gas to be recovered to desorb from the adsorbent material (12) by heating the periphery of the adsorbent material (12) under a reduced pressure state; and a fan (61) having a quantity set to be less than the quantity of the plurality of modules (11) and supplying gas to the interiors of the plurality of modules (11); and, on each of the plurality of modules (11), valves (23, 24) are respectively provided at the gas inlet and outlet, and the valve opening degree of at least one of the valves (23, 24) varies according to the adsorption progress of the gas to be recovered in the module (11) where the valve (23, 24) is provided.

[0016] A second disclosure is the gas recovery device (1) according to the first disclosure, wherein the valve opening degree of at least one of the valves (23, 24) decreases as the adsorption time of the gas to be recovered elapses.

[0017] (Effects of the Invention)

[0018] According to the present disclosure, a gas recovery device can be provided. It is a modular gas recovery device with multiple adsorption modules, and dedicated fans corresponding to each adsorption module are not individually provided, which can reduce the work done by the fans, thereby reducing the energy used for gas adsorption operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram showing the configuration related to the flow of liquid in the carbon dioxide recovery device 1 of the gas recovery device according to an embodiment of the present invention.

[0020] Figure 2 It is a schematic diagram showing the configuration related to the flow of gas in the module 11 of the carbon dioxide recovery device 1 of the present embodiment.

[0021] Figure 3 It is a diagram showing an example of the connection form between the module 11 and the fan 61.

[0022] Figure 4 It is a diagram showing an example of the configuration of the module 11 and also shows a part of the inside of the module 11.

[0023] Figure 5 It is a diagram showing an example of the internal configuration of the third valve 23.

[0024] Figure 6 It is a diagram showing an example of the internal configuration of the fourth valve 24.

[0025] Figure 7 It is a diagram showing the change in the CO2 concentration at the outlet of the adsorption module when an air flow containing CO2 equal to the CO2 adsorption rate exerted by the adsorption material at an adsorption amount of 0 is supplied to the adsorption material module with an initial CO2 adsorption amount of 0.

[0026] Figure 8 It shows Figure 7 a diagram showing the change in the adsorption amount under the same conditions.

[0027] Figure 9 It is a diagram for Figure 8 further explaining the diagram showing the change in the adsorption amount.

[0028] Figure 10 It is a diagram showing the required air flow and valve opening degree that change as the processing in each module progresses.

[0029] Figure 11 It is a diagram showing the relationship between the opening degree of the butterfly valve 24a and the air flow.

[0030] Figure 12It is a diagram showing the air flow rate through each module when the opening degree of the butterfly valve 24a of all modules is set to an opening degree that achieves the following air flow rate, where the air flow rate contains a CO2 flow rate that matches the adsorption amount QH at the start of adsorption.

[0031] Figure 13 It is a diagram showing the air flow rate through each module when the opening degree of the butterfly valve 24a of each module is set to an opening degree that achieves the following air flow rate, where the air flow rate contains a CO2 flow rate that matches the change in the adsorption amount Q of each module. Detailed implementation mode

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0033] <Overall configuration>

[0034] Figure 1 It is a schematic diagram showing the configuration related to the flow of liquid in the carbon dioxide recovery device 1, which is an embodiment of the present invention. Figure 2 It is a schematic diagram showing the configuration related to the gas flow in the module 11 of the carbon dioxide recovery device 1 of the present embodiment. Additionally, in Figure 1 the illustration of the configuration related to the gas flow in the carbon dioxide recovery device 1 is omitted. Additionally, in the following description, the carbon dioxide recovery device 1, which is an example of a gas recovery device, is illustrated for description, but the configuration using the flow rate control of the valve disclosed in the present application can also be similarly applied to the case of recovering gases other than carbon dioxide.

[0035] The carbon dioxide recovery device 1 of the present embodiment is applied, for example, to the direct air capture technology (DAC: Direct Air Capture) for recovering carbon dioxide from the atmosphere to reduce the carbon dioxide concentration in the atmosphere. The carbon dioxide recovered by the carbon dioxide recovery device 1 is stored underground or reused as fuel or materials.

[0036] As Figure 1 and Figure 2 shown, the carbon dioxide recovery device 1 of the present embodiment includes a module unit 10, a fan 61, a vacuum pump 62, a carbon dioxide recovery pump 63, a heat exchange device 80, and a control device 90.

[0037] The module unit 10 is composed of a plurality of modules 11 for adsorbing carbon dioxide arranged in parallel. In the present embodiment, a total of 16 modules 11 are arranged by means of a pair of left and right module units 10.

[0038] As Figure 2As shown, module 11 is a carbon dioxide recovery module, which includes an adsorption material 12, a first valve 21, a second valve 22, a third valve 23, a fourth valve 24, and an adsorption material temperature sensor 27.

[0039] The adsorption material 12 is arranged inside the module 11 to adsorb carbon dioxide. The adsorption material 12 is a granular component and has the following properties: it adsorbs carbon dioxide at a low temperature (for example, in the range of -30°C to 50°C), and releases (desorbs) carbon dioxide at a high temperature (for example, in the range of 50°C to 110°C) and when the concentration of carbon dioxide in the surrounding environment is low. As such an adsorption material 12, for example, a solid amine carbon dioxide adsorption material formed by supporting an amine on a porous material such as silica can be cited.

[0040] The first valve 21 is a switching valve arranged at the connection part between the carbon dioxide pipeline 103 for recovering carbon dioxide and the module 11. A carbon dioxide recovery pump 63 is arranged on the carbon dioxide pipeline 103. The second valve 22 is a switching valve arranged at the connection part between the vacuum pipeline 102 equipped with a vacuum pump 62 and the module 11. The third valve 23 is a switching valve arranged at the entrance for sucking air or the like into the inside of the module 11. The fourth valve 24 is a switching valve arranged at the connection part between the adsorption pipeline 101 and the module 11. A fan 61 is arranged on the adsorption pipeline 101.

[0041] The switching of the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 is all controlled by the control device 90. The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are, for example, butterfly valves that are normally open.

[0042] Figure 3 is a diagram showing an example of the connection form between the module 11 and the fan 61. Figure 4 is a diagram showing a configuration example of the module 11 and also shows a part of the inside of the module 11. In Figure 3 the example shown, on two opposite surfaces in a direction orthogonal to the extending direction (length direction) of the pipeline of the adsorption pipeline 101, each surface is respectively provided with 8, a total of 16 modules 11. These modules 11 are arranged in parallel with the adsorption pipeline 101, and the fourth valve 24 is connected to the adsorption pipeline 101. That is, the adsorption pipeline 101 is respectively branched and connected to each module 11. In addition, Figure 3 the arrangement of the module 11 shown relative to the adsorption pipeline 101 is an example, and it can also be other arrangements.

[0043] As Figure 4As shown, the module 11 includes a box-shaped housing 15, a heat exchange section 16 disposed inside thereof, and a third valve 23 and a fourth valve 24 provided on two opposite faces of the housing 15. The housing 15 is a box-shaped member and includes an adsorption material 12 inside thereof. For example, as Figure 4 shown, the adsorption material 12 includes a plurality of thin plate-shaped fins and tubes (not shown), and is filled between the fins of a support body laminated in a corrugated shape.

[0044] A fan 61 is provided at a portion where the branched portions of the adsorption pipeline 101 converge. By driving the fan 61, a gas flow from "suction" to "exhaust" is generated in each of the plurality of modules 11 disposed on the upstream side of the adsorption pipeline 101. Thereby, the atmosphere is supplied into the module 11.

[0045] Regarding the third valve 23 and the fourth valve 24, in Figure 2 for the sake of easy understanding, an example in which one is provided in each module 11 is shown. However, as Figure 2 and Figure 3 shown, two can be provided respectively in one module 11, or a larger number can be provided.

[0046] Figure 5 is a diagram showing an example of the internal structure of the third valve 23. Figure 5 The right side in Figure 5 is the inlet side of the atmosphere, and the left side is connected to the module 11. As Figure 5 shown, the third valve 23 includes an actuator (not shown) driven and controlled by a control device 90, and a butterfly valve 23a rotated and operated by the actuator rotates between a fully closed state ( Figure 5 the state of 0° in

[0047] Figure 6 is a diagram showing an example of the internal structure of the fourth valve 24. Figure 6 The right side in Figure 6 is connected to the module 11, and the left side is connected to the fan 61 via the adsorption pipeline 101. As Figure 6 shown, the fourth valve 24 includes an actuator (not shown) driven and controlled by a control device 90, and a butterfly valve 24a rotated and operated by the actuator rotates between a fully closed state ( Figure 6rotates between the states of 90°. Thus, the fourth valve 24 switches between blocking and introducing the atmosphere flowing into the module 11. In addition, the fourth valve 24 of the present embodiment is controlled by the control device 90 during the adsorption process, and the valve opening changes according to the CO2 adsorption progress of the module 11, and can also be set to an intermediate valve opening between the fully closed state and the fully open state ( Figure 6 in the metering state). In addition, in , the metering state of the butterfly valve 24a is illustrated, but the opening of the butterfly valve 24a continuously changes between the state of 0° and the state of 90°. More specifically, during the adsorption process of the fourth valve 24 of the present embodiment, as the CO2 adsorption time progresses, the valve opening decreases. The details of the adjustment (metering) of the valve opening of the fourth valve 24 will be described below.

[0048] Return Figure 6 , the adsorbent temperature sensor 27 measures the temperature of the adsorbent 12. The measurement information of the adsorbent temperature sensor 27 is sent to the control device 90.

[0049] The vacuum pipelines 102 are respectively branched and connected to each module 11. The vacuum pump 62 is arranged at the part where the branched parts of the vacuum pipelines 102 gather. By driving the vacuum pump 62, the gas inside the module 11 is sucked through the vacuum pipelines 102, so that the inside of the module 11 is in a vacuum state or a state close to vacuum.

[0050] The carbon dioxide pipelines 103 are respectively branched and connected to each module 11. At the part where the branched parts of the carbon dioxide pipelines 103 gather, a carbon dioxide recovery pump 63 is arranged. The carbon dioxide recovery pump 63 exerts a suction force on the carbon dioxide flowing in the carbon dioxide pipeline 103, and stores the recovered carbon dioxide in a tank for storing carbon dioxide (not shown).

[0051] Return Figure 2 The heat exchange device 80 will be described. When each module 11 of the module unit 10 performs the detachment process, the heat exchange device 80 supplies the thermal energy for heating the inside of the module 11 to a specified temperature. In addition, the heat exchange device 80 recovers the thermal energy that is not required when each module 11 performs the adsorption process.

[0052] The heat exchange device 80 of the present embodiment includes a heat exchanger 81, a cold water tank 82, a cold water pipeline 111, a hot water tank 83, a hot water pipeline 112, and a three-way valve 30.

[0053] The heat exchanger 81 performs heat exchange between the heat medium flowing in the cold water pipeline 111 and the heat medium flowing in the hot water pipeline 112. The heat exchanger 81 is, for example, a heat pump. The heat medium is, for example, a liquid such as water. Through the heat transfer generated in the heat exchanger 81, the heat medium flowing in the cold water pipeline 111 is cooled, and the heat medium flowing in the hot water pipeline 112 is heated.

[0054] The cold water tank 82 stores the heat medium flowing in the cold water pipeline 111. After the heat medium flowing in the cold water pipeline 111 is stored in the cold water tank 82, it is transported to the heat exchanger 81. In addition, after the heat medium cooled by the heat exchanger 81 returns to the cold water tank 82, it is transported to each module 11 through the cold water pipeline 111. Between the cold water tank 82 and the heat exchanger 81 on the cold water pipeline 111, a heat exchanger circulation water pump 821 is arranged. By driving the heat exchanger circulation water pump 821, the heat medium flowing in the cold water pipeline 111 circulates between the cold water tank 82 and the heat exchanger 81.

[0055] The cold water pipeline 111 is respectively branched and connected to the upstream side and the downstream side of each module 11, connecting the cold water tank 82 and each module 11. In addition, between the cold water tank 82 and each module 11 on the cold water pipeline 111, a first cold water circulation water pump 822 and a second cold water circulation water pump 823 are arranged. In addition, on the cold water pipeline 111, a circulation pipeline 824 that returns from the downstream side of the second cold water circulation water pump 823 to the upstream side is arranged. A circulation valve 825 is arranged on the circulation pipeline 824.

[0056] The hot water tank 83 stores the heat medium flowing in the hot water pipeline 112. After the heat medium flowing in the hot water pipeline 112 is stored in the hot water tank 83, it is transported to the heat exchanger 81. In addition, after the heat medium heated by the heat exchanger 81 returns to the hot water tank 83, it is transported to each module 11 through the hot water pipeline 112. Between the hot water tank 83 and the heat exchanger 81 on the hot water pipeline 112, a heat exchanger circulation water pump 831 is arranged. By driving the heat exchanger circulation water pump 831, the heat medium flowing in the hot water pipeline 112 circulates between the hot water tank 83 and the heat exchanger 81.

[0057] The hot water pipeline 112 is respectively branched and connected to the upstream side and the downstream side of each module 11, connecting the hot water tank 83 and each module 11. In addition, between the hot water tank 83 and each module 11 on the hot water pipeline 112, a first hot water circulation water pump 832 and a second hot water circulation water pump 833 are arranged. In addition, on the hot water pipeline 112, a circulation pipeline 834 that returns from the downstream side of the second hot water circulation water pump 833 to the upstream side is arranged. A circulation valve 835 is arranged on the circulation pipeline 834.

[0058] The three-way valve 30 is connected to the cold water pipeline 111, the hot water pipeline 112, and the module 11. The three-way valve 30 is respectively arranged on the upstream side and the downstream side of the module 11. The three-way valve 30 is configured to be able to switch between a cold water connection state in which the cold water pipeline 111 is connected to the module 11, a hot water connection state in which the hot water pipeline 112 is connected to the module 11, and a blocking state in which the connections of the cold water pipeline 111 and the hot water pipeline 112 to the module 11 are blocked.

[0059] The flow path switching of the three-way valve 30 is controlled by the control device 90. For the module 11, the heat medium is introduced through the three-way valve 30 arranged on the upstream side, and through the three-way valve 30 arranged on the downstream side, the heat medium returns to the heat exchanger 81 side.

[0060] Next, the control device 90 will be described. The control device 90 controls the operations of various parts of the carbon dioxide recovery device 1. The control device 90 controls the operations such as driving or stopping of the equipment for carbon dioxide adsorption or desorption. The control device 90 performs the on-off control of the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 provided in each module 11, etc. In addition, the control device 90 performs the drive control of the fan 61, the vacuum pump 62, the carbon dioxide recovery pump 63, the heat exchanger circulating water pump 821, the first cold water circulating water pump 822, the second cold water circulating water pump 823, the heat exchanger circulating water pump 831, the first hot water circulating water pump 832, the second hot water circulating water pump 833, etc., and the on-off control of the circulation valve 825 and the circulation valve 835.

[0061] The control device 90 is, for example, a computer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), etc. The control device 90 can be composed of one unit or multiple units.

[0062] <Recovery of carbon dioxide>

[0063] Next, the control for recovering carbon dioxide using the control device 90 will be described. The carbon dioxide recovery device 1 removes and recovers carbon dioxide from the air in the following manner: alternately performing an adsorption process and a desorption process, compressing the desorbed carbon dioxide, and storing it in a tank (not shown). The adsorption process is to make the adsorption material 12 in the module 11 adsorb carbon dioxide in the sucked air and other gases, and the desorption process is to desorb the carbon dioxide adsorbed by the adsorption material 12. In the present embodiment, the adsorption process and the desorption process are carried out with the time of the adsorption process: the time of the desorption process = 7:1.

[0064] The adsorption process is a process in which the adsorbent material 12 in the module 11 adsorbs carbon dioxide. In the adsorption process, the third valve 23 and the fourth valve 24 of the module 11 are opened, and the first valve 21 and the second valve 22 are closed. The fan 61 is driven to generate a gas flow from upstream to downstream, and the gas containing carbon dioxide (for example, the atmosphere) is sucked through the third valve 23. The sucked gas passes through the adsorbent material 12 in the module 11. At this time, the inside of the module 11 is at room temperature (25 °C), and the carbon dioxide in the gas is adsorbed by the adsorbent material 12. Gases other than carbon dioxide, such as nitrogen or oxygen, are discharged to the outside of the carbon dioxide recovery device 1 through the fourth valve 24 and the adsorption pipeline 101. In addition, in the present embodiment, in this adsorption process, the valve opening degree of the fourth valve 24 is adjusted (regulated).

[0065] The desorption process is a process in which the carbon dioxide of the adsorbent material 12 in the module 11 is desorbed. In the desorption process, the first valve 21, the third valve 23, and the fourth valve 24 of the module 11 are closed, and the second valve 22 is opened. The vacuum pump 62 operates to suck the inside of the module 11 and decompress it to a vacuum state or a state close to a vacuum state. At the same time, by means of the heat exchange device 80, a heat medium as a heat source flows in the module 11 to supply heat energy, and the adsorbent material 12 of the module 11 is heated up.

[0066] By controlling the temperature rise of the adsorbent material 12, the adsorbent material 12 is also heated to a specified temperature (for example, 80 °C) sufficient to perform the desorption process, and the carbon dioxide adsorbed by the adsorbent material 12 is desorbed. Then, the second valve 22, the third valve 23, and the fourth valve 24 are closed, the first valve 21 is opened, and the carbon dioxide recovery pump 63 is driven to store the desorbed carbon dioxide in a tank (not shown) through the carbon dioxide pipeline 103. In the present embodiment, each process is controlled so that 12 of the 16 modules 11 perform the adsorption process, and the remaining 4 modules perform the desorption process.

[0067] <Adjustment of the valve opening degree of the fourth valve 24 (regulation)>

[0068] As described above, the valve opening of the fourth valve 24 in the present embodiment decreases as the CO2 adsorption time elapses in the adsorption process. This is a control corresponding to the change in the CO2 adsorption rate of the module 11 over time after the start of adsorption. At the start of CO2 adsorption, adsorption occurs very rapidly in the adsorption material 12, but as adsorption progresses, the adsorption rate gradually slows down and eventually gradually approaches the equilibrium adsorption amount, reaching a state where almost no adsorption occurs. Therefore, the supply amount of the atmosphere to be supplied to the module 11 gradually decreases as adsorption progresses. Thus, in the present embodiment, control is performed such that the valve opening decreases as the CO2 adsorption time elapses in the adsorption process, thereby optimizing the supply amount of the atmosphere in each module. By this control, a necessary and sufficient amount of the atmosphere is supplied to the plurality of provided modules 11. Therefore, the required air volume of the fan 61 can also be optimized, and thus, in the present embodiment, the work done by the fan 61 is significantly reduced compared to the past. Hereinafter, using the model of 8 joules exemplified in Figure 1 the reduction effect of the work done by the fan will be described.

[0069] <CO2 Adsorption Progress of Adsorption Material in Adsorption Process>

[0070] First, the CO2 adsorption progress of the adsorption material in the adsorption process will be described. In the following description, the following values are assumed for the mass transfer coefficient k, the equilibrium adsorption amount Q*, the initial adsorption amount Q0, and the CO2 concentration in the air.

[0071] Mass transfer coefficient k: k = 4×10 -4 (1 / s)

[0072] Equilibrium adsorption amount Q*: Q* = 2.3 (mol / kg)

[0073] Initial adsorption amount Q0: Q0 = 0 (mol / kg)

[0074] CO2 concentration in the air: C = 400 (ppm)

[0075] In addition, the adsorption module is, for example, set to be provided with 8 as exemplified in Figure 3 and a model in which 8 adsorption modules are sequentially adsorbed and desorbed in a staggered time sequence (hereinafter, also referred to as adsorption and desorption cycle operation) will be described. The ratio of the time length ta of the adsorption step in which air flows through the adsorption module to the total time length td of the preheating step, the desorption step for CO2 desorption, and the cooling step for adsorption preparation, etc., which are not related to air flow, is 7:1 as follows.

[0076] ta:td = 7:1

[0077] In the case of this model, the progress of CO2 adsorption will be described.Figure 3 It is a graph showing the change in the CO2 concentration at the outlet of the adsorption module when an air flow containing CO2 equal to the CO2 adsorption rate of the adsorption material when the initial CO2 adsorption amount is 0 is supplied to the adsorption material module with an initial CO2 adsorption amount of 0. Figure 7 It is a graph showing Figure 8 the change in the adsorption amount under the same conditions.

[0078] After time 0, the outlet CO2 concentration is immediately greater than 0, and as time passes, it gradually approaches 400 (ppm). Synchronously, the adsorption amount increases from 0 and gradually approaches the equilibrium adsorption amount of 2.3 (mol / kg).

[0079] <Operation of the CO2 recovery device>

[0080] Figure 7 It is a graph for supplementary explanation of Figure 9 the change in the adsorption amount. In the actual adsorption - desorption cycle operation of the CO2 recovery device, the adsorption amount cycles between QL greater than 0 and QH less than the equilibrium adsorption amount. Thus, in each cycle, CO2 equivalent to the working capacity (ΔQ = QH - QL), which is the difference between QH and QL, is recovered.

[0081] As an example, the working capacity of 80% of the equilibrium adsorption amount is set and explained as follows.

[0082] QL = 0.1Q* = 0.23 (mol / kg)

[0083] QH = 0.9Q* = 2.07 (mol / kg)

[0084] Thus,

[0085] ΔQ = QH - QL = 0.8Q* = 1.84 (mol / kg)

[0086] If the time is counted from time 0, and the time when the adsorption amount reaches QL is set as tL, and the time when it reaches QH is set as tH, then the time ta required for the adsorption step from QL to QH is as follows.

[0087] ta = tH - tL

[0088] In addition, the time Td from the time point of TH through the desorption step, etc., until the adsorption amount returns from QH to QL again is as follows.

[0089] td = ta / 7

[0090] When the working capacity during the cyclic adsorption and desorption operation ranges from 10% (designated as QL) to 90% (designated as QH) of the equilibrium adsorption capacity Q*, for the following two cases of air flow rate setting methods in the adsorption step, the difference in the air introduction work (J) is confirmed using the linear driving force model, thereby theoretically explaining the superiority of this method.

[0091] (1) Fixed air flow rate driving: The case where the adsorption step is carried out within the range from QL to QH at an air flow rate (fixed value) matching QL.

[0092] (2) Adsorption capacity feedback driving: The case where the adsorption step is carried out at an air flow rate (time-varying value) matching the adsorption capacity Q that changes from QL to QH.

[0093] In the case of fixed air flow rate driving, when the adsorption step is carried out at an air flow rate (fixed value) matching QL, the air flow rate F AIR (m 3 / s / kg) can be expressed in the following manner using the coefficient η for converting moles to volume.

[0094] [Mathematical formula 1]

[0095]

[0096] The experimental formula, the Ergun equation, represents the pressure loss (Pa) in the adsorption layer filled with granular adsorbent material. According to the Ergun equation, the pressure loss is composed of the sum of a term proportional to the first power of the superficial air velocity (m / s) flowing into the adsorption layer and a term proportional to the second power of the superficial air velocity (m / s) flowing into the adsorption layer. It is known that when using a thin plate-shaped adsorption layer, it is roughly dominated by the first component. In this case, the pressure loss P a (Pa) can be expressed in the following manner.

[0097] [Mathematical formula 2]

[0098]

[0099] Therefore, the pressure loss P w (W / kg) can be expressed in the following manner.

[0100] [Mathematical formula 3]

[0101]

[0102] When measuring the outlet CO2 concentration and module flow rate of each adsorption module, referring to the adsorption capacity Q calculated from them, and carrying out the adsorption step at a flow rate (time-varying value) matching the adsorption capacity Q that changes from QL to QH, the air flow rate F AIR’ (m 3 / s / kg) can be expressed as follows using the proportionality coefficient η.

[0103] [Formula 4]

[0104]

[0105] Here, when the adsorption material having an adsorption amount of 0 starts adsorption at time 0, the adsorption amount Q is expressed as a function of time t in the following manner.

[0106] [Formula 5]

[0107]

[0108] Here, the above equation (d) is the solution of the linear drive model: dQ / dt = k(Q*-Q). Therefore, equation (a') can be rewritten as the following equation (a").

[0109] [Formula 6]

[0110]

[0111] Pressure loss P a’ (Pa) can be expressed as follows using (a”).

[0112] [Formula 7]

[0113]

[0114] Therefore, the pressure loss P w’ (W / kg) can be expressed as follows.

[0115] [Formula 8]

[0116]

[0117] The pressure loss E (J / kg) and E' (J / kg) are calculated by integrating equations (c) and (c') over the time it takes for the adsorption amount to transition from QL to QH. This time is assumed to be adsorption starting from a state where the adsorption amount is zero according to equation (d). The time t is calculated. L and time t H The time t of QL L and QH time t H It can be expressed as follows.

[0118] [Formula 9]

[0119]

[0120] Therefore, based on equations (d), (e), and (c), the pressure loss E (J / kg) during constant air flow rate control can be expressed as follows.

[0121] [Mathematical formula 10]

[0122]

[0123] According to formula (e), (f) and formula (c’), the pressure loss E’ (J / kg) during adsorption amount feedback control can be expressed in the following manner.

[0124] [Mathematical formula 11]

[0125]

[0126] The calculation conditions here are k = 4×10 -4 (1 / s), Q* = 2.3 (mol / kg). Therefore, if these values are applied to formula (c2) and (c2’), it is as follows.

[0127] [Mathematical formula 12]

[0128]

[0129] From the above, it can be known that when the working capacity is within the range of 10% (=QL) to 90% (=QH) of the equilibrium adsorption amount Q*, in the case of the adsorption step being carried out at a fixed air flow rate matching QL, and in the case of the adsorption step being carried out at a matching flow rate (time-varying value) corresponding to the adsorption amount Q that changes from QL to QH, it is speculated that the air introduction work (J) in the latter case is 18.2% of the air introduction work in the former case. In addition, this 18.2% value is obtained based on the comparison (4840 / 26586×100) of the formulas (C3) and (C’3) representing the pressure loss. Thus, the superiority of the adsorption amount feedback drive for adjusting (regulating) the valve opening of the fourth valve 24 proposed in the present disclosure can be confirmed. In addition, here, a model with ta:td = 7:1 is described, but regarding the above superiority, for example, even when ta:td = 3:1, the same result is obtained. Among them, this reduction effect is the result of a comparative evaluation of the air introduction work (J / kg) contributed by the adsorption material.

[0130] If taking 7 adsorption modules + 1 desorption module = 8 modules as a group, for this group of 8 modules, if the step time of each module is delayed by (ta + td) / 8 in sequence, and the adsorption is completed in sequence, and the desorption step is carried out in sequence, then overall, the adsorption progresses in sequence in each module, and there are always 7 modules carrying out the adsorption process and 1 module carrying out the desorption process. In this case, the appropriate air flow rate required for the 7 modules varies as Figure 8 such, and its average value (m 3 / s / kg) is:

[0131] [Mathematical formula 13]

[0132]

[0133] On the other hand, the air flow rate F when driven by a fixed air flow rate represented by formula (a) AIR = F AIRconst can be expressed in the following manner.

[0134] [Mathematical formula 14]

[0135]

[0136] That is to say, first, it is clear that with respect to the flow rate 0.9 ηkQ* during fixed air flow rate driving, the average air flow rate 0.3641 ηkQ* required in adsorption amount feedback driving only needs to be 40.46%.

[0137] Next, the calculation method of the pressure loss (J / kg) will be described. It is necessary to satisfy the pressure constraint requirement that "even in the case of adsorption amount feedback driving with flow rate control of the downstream valve, the pressure loss (Pa) between the upstream and downstream of the module achieved by fixed air flow rate driving must also be generated". Hereinafter, the reason for this requirement will be described.

[0138] (1) As Figure 10 , Figure 12 shown, with respect to the air intake fan, the modules as loads are connected in parallel. Then, the pressure Pus outside the air inlet valve of the module is constrained to the atmospheric pressure Pair. Further, the air pressure Pds outside the downstream air outlet valve is constrained to a certain fixed pressure value lower than the atmospheric pressure due to the driving force of the air fan. This pressure difference Pus - Pds becomes the driving force, and in the case of fixed air flow rate driving, the air flow rate represented by formula (a) is generated.

[0139] (2) Similarly, due to this pressure difference, in the case of adsorption amount feedback driving, it is necessary to immediately pass the air flow rate represented by formula (a) through the module after the start of the adsorption step. Conversely, if there is no such pressure difference, it is impossible to ensure the necessary and sufficient air flow rate for the module shortly after the start of the adsorption step. From the above (1) and (2), it can be seen that the above requirements need to be satisfied.

[0140] According to the above requirements, whether it is the case of fixed air flow rate drive or adsorption amount feedback drive, the pressure difference Pus - Pds (Pa) between the pressures on the outer sides of the upstream and downstream valves must be the same. On this basis, in the adsorption amount feedback drive, by appropriately throttling the air flow rate using the downstream valve, the pressure loss of the adsorption material itself is reduced. Conversely, the valve pressure loss is increased to compensate for the reduction in the pressure loss of the adsorption material (since the valve pressure loss is determined by such logic, in fact, there is no need to specify the type of valve. As long as it is a valve that can smoothly change its characteristics between fully open and fully closed, it can be used for flow control).

[0141] Under these conditions, between the two drive modes, the air flow rates are different. The average flow rate required in the adsorption amount feedback drive, which is 0.3641 ηkQ*, only needs to be 40.46% of the air flow rate 0.9 ηkQ* in the fixed air flow rate drive. Therefore, the pressure loss (W / kg) of the latter only needs to be 40.46% of that of the former. 40.46% is the effect obtained in this example.

[0142] Utilize Figure 13 To illustrate the relationship between the downstream valve opening and the air flow rate in the case of fixed air flow rate drive.

[0143] • Modules #1 (hereinafter, also only referred to as #1, and the same applies to other modules) to #7 are performing the adsorption step, and #8 is performing the desorption step.

[0144] • Always supply the air flow rate corresponding to the low-side adsorption amount QL = 0.1Q* of the working capacity to the 7 modules in the adsorption step.

[0145] • #1 is the start stage of the adsorption step, #7 is the last stage of the adsorption step. After the desorption step of #8 ends, #7 enters the desorption step, and at the same time, #8 enters the adsorption step.

[0146] In addition, when the valve is fully open (90 degrees), it is shown as the opening corresponding to Q = Q*. Therefore, the valve opening of each module corresponding to Q = QL is 78 degrees, rather than 90 degrees (fully open).

[0147] Utilize Figure 12 To illustrate the relationship between the downstream valve opening and the air flow rate in the case of adsorption amount feedback drive.

[0148] • Modules #1 to #7 are performing the adsorption step, and #8 is performing the desorption step.

[0149] • Supply the air flow rate corresponding to the adsorption amount of each module to the 7 modules in the adsorption step.

[0150] • #1 is the start stage of the adsorption step, #7 is the last stage of the adsorption step. After the detachment step of #8 ends, #7 enters the detachment step, and at the same time, #8 enters the adsorption step.

[0151] In addition, when the valve is fully open (90 degrees), it is shown as the opening corresponding to Q = Q*. Therefore, the valve opening of each module corresponding to Q = QL is 78 degrees, not 90 degrees (fully open). In addition, Figure 13 the shaded time interval in Figure 10 corresponds to the time period of the valve opening shown.

[0152] <Required air flow rate and valve opening>

[0153] Figure 13 is a graph showing the required air flow rate and valve opening that change as the processing in each module progresses. Figure 10 The upper graph in Figure 10 represents the air flow rate, and the lower graph represents the valve opening. In addition, Figure 10 the air flow rate in

[0154] is expressed as the flow rate per unit mass of the adsorbent material (mol / s / kg). In Figure 10 the air flow rate matching the maximum adsorption amount QH providing the working capacity is 2.07 (mol / s / kg). Figure 10 Each thin line with the module number attached in Figure 10 is the air flow rate matching the adsorption level of each module, which varies in the range of 2.07 - 0.23 mol / s / kg. In addition, the thick zigzag line is the total air flow rate matching the adsorption level of each module, which varies in the range of 0.62 - 0.85 mol / s / kg. Compared with the case of continuously flowing the air flow rate matching the maximum adsorption amount QH, in the case of flowing the air flow rate matching the adsorption level of each module, the air introduction work to the adsorbent material layer of the latter is 18.2% of the former. Figure 10 The thick zigzag line in

[0155] <Required valve opening>

[0156] • According to the following "relationship between valve opening and air flow rate" and the aforementioned "required air flow rate", it can be as Figure 10The valve opening degrees (degrees) of each module are shown as below. Here, fully closed is 0 deg, and fully open is 90 deg. The maximum valve opening degree at the minimum adsorption amount QL is taken as 78 deg at most, and the minimum value of the valve opening degree at the maximum adsorption amount QH is taken as 31.7 deg. In Figure 10 In it, the solid line is the valve opening degree of module number #1, and the dashed line is the valve opening degree of module number #2. After reaching the maximum adsorption amount, the valve opening degree immediately turns rapidly to fully closed. Similarly to the example of the module number 8, by controlling the fourth valve 24 using the control device 90, the work amount required for the fan 61 in this embodiment can be significantly reduced.

[0157] <Required air flow rate>

[0158] The optimal air flow rate FAIR_opt (mol / s / kg) required for the eight-module carbon dioxide recovery device obtained when the carbon dioxide recovery device operates stably in a fixed environment is as described above in a sawtooth shape. Relative to the average value of 5.89, the maximum value is 6.83, and the minimum value is 4.99. Relative to the average value, there are variations of +16.0% and -15.2%. As long as the fan performs flow feedback operation in a manner that supplies a rough value of the above average value of 5.89 (mol / g / kg), the power consumption of the air supply fan can be sufficiently reduced, but the adsorption distribution curve of each module will deviate slightly from the target value.

[0159] To solve this problem, it is only necessary to perform flow feedback operation with the air flow rate of the fan being the optimal air flow rate FAIR_opt (mol / s / kg). In this case, the following (Phenomenon 1) will occur, and at the same time, (Phenomenon 2) will occur.

[0160] (Phenomenon 1) The adsorption and desorption characteristics are optimal, and therefore, the CO2 production (tCO2 / year) is also the largest.

[0161] (Phenomenon 2) The operating point of the fan changes slightly, so the efficiency of the drive motor and the conversion efficiency of the fan cannot be maintained at the optimal point.

[0162] Considering the balance between the above (Phenomenon 1) and (Phenomenon 2), fixed control, variable control, or between the two of the air flow rate can be selected. In this embodiment, the operating state of the fan is maintained fixed as much as possible. Thus, the regions with good efficiency of the fan and the motor, and the regions with good conversion efficiency from the shaft input of the fan to air work can be combined and set, and an efficient air supply system can be made as a whole.

[0163] <Relationship between valve opening degree and air flow rate>

[0164] Figure 10It is a graph showing the relationship between the opening degree of the butterfly valve 24a and the air flow rate. In the case of this embodiment, the pressure difference between the upstream and downstream of the fourth valve 24 is substantially fixed. However, if the butterfly valve 24a is used to control the flow rate, there is a tendency to exhibit characteristics relatively suitable for flow control as shown in Figure 11 Figure 11 That. Utilizing this characteristic, it is possible to allocate an appropriate air flow rate according to the adsorption amount of each module.

[0165] However, as described above, regardless of the flow characteristics of the valve, as long as it is a valve that can smoothly change its characteristics between fully open and fully closed, it can be used for the above-mentioned flow control.

[0166] <Estimation of CO2 adsorption amount>

[0167] The CO2 adsorption amount can be directly estimated by measuring the CO2 concentration at the inlet and outlet of each module and the air flow rate of each module, and the valve opening degree is controlled according to this estimated value. In this case, the valve control is updated in consideration of the long-term change in the adsorption characteristics of the module. In addition, the time-course characteristics of adsorption can be pre-held as a MAP, and the valve opening degree can be adjusted accordingly. Even in the case of controlling using such a MAP, the long-term change in the adsorption characteristics can be detected by typically using the CO2 concentration at the inlet and outlet of the unit that is an aggregate of the modules, and the valve control can be updated in a manner that reflects this change, thereby suppressing the performance deterioration of the unit to the minimum.

[0168] As described above, according to the carbon dioxide recovery device 1 of this embodiment, the opening degree of the fourth valve 24 is changed so as to be an appropriate opening degree corresponding to the progress of carbon dioxide adsorption. Therefore, the work amount required for the fan 61 can be reduced.

[0169] (Variant form)

[0170] It is not limited to the embodiment described above, and various deformations or changes are possible, and these deformations or changes are also within the scope of this disclosure.

[0171] (1) In the embodiment, the following example was described: The opening degree of the fourth valve 24 provided on the outlet side of the module 11 is changed according to the progress of carbon dioxide adsorption. However, it is not limited to this. For example, the opening degree of the third valve 23 provided on the inlet side can also be changed according to the progress of carbon dioxide adsorption, and the valve opening degrees of both the third valve 23 and the fourth valve 24 can also be changed.

[0172] (2) In the embodiment, the following examples are illustrated: 16 modules 11 are provided, and adsorption and detachment are performed in sequence for every 8 modules as a group. Thus, the time of the adsorption process: the time of the detachment process is set to 7:1. However, it is not limited thereto. For example, the number of modules can be set to 24 or 32. In addition, for example, when using an adsorption material for which the time of the adsorption process: the time of the detachment process is appropriately 3:1, it is appropriate to implement it at 3:1. In this case, modules 11 that are multiples of 4, such as 4 or 8, are selected. That is to say, these values are appropriate values adopted in consideration of the ratio of the time of the adsorption process to the time of the detachment process of the adsorption material and the scale of the carbon dioxide recovery device 1.

[0173] Reference numeral

[0174] 1 Carbon dioxide recovery device (gas recovery device)

[0175] 10 Module unit

[0176] 11 Module

[0177] 12 Adsorption material

[0178] 15 Housing

[0179] 21 First valve

[0180] 22 Second valve

[0181] 23 Third valve

[0182] 23a Butterfly valve

[0183] 24 Fourth valve

[0184] 24a Butterfly valve

[0185] 27 Adsorption material temperature sensor

[0186] 30 Three-way valve

[0187] 61 Fan

[0188] 62 Vacuum pump

[0189] 63 Carbon dioxide recovery pump

[0190] 80 Heat exchange device

[0191] 81 Heat exchanger

[0192] 82 Cold water tank

[0193] 83 Hot water tank

[0194] 90 Control device

[0195] 101 Adsorption pipeline

[0196] 102 Vacuum pipeline

[0197] 103 Carbon dioxide pipeline

[0198] 111 Cold water pipeline

[0199] 112 Hot water pipeline

[0200] 400 Over time

[0201] 821 Water pump for heat exchanger circulation

[0202] 822 First water pump for cold water circulation

[0203] 823 Second water pump for cold water circulation

[0204] 824 Circulation pipeline

[0205] 825 Circulation valve

[0206] 831 Water pump for heat exchanger circulation

[0207] 832 First water pump for hot water circulation

[0208] 833 Second water pump for hot water circulation

[0209] 834 Circulation pipeline

[0210] 835 Circulation valve

Claims

1. A gas recovery device comprising: a plurality of modules having an adsorbent material therein and performing an adsorption process and a desorption process, the adsorption process being to suck a gas containing a gas to be recovered to the adsorbent material to cause the adsorbent material to adsorb the gas to be recovered, and the desorption process being to heat the periphery of the adsorbent material under a reduced pressure state to cause the gas to be recovered to desorb from the adsorbent material; and, a fan, the number of which is set to be less than the number of the modules and which supplies gas to the interiors of the plurality of modules; and, valves are respectively provided at the gas inlet and outlet of each of the plurality of modules, the valve opening degree of at least one of the valves varies according to the adsorption progress of the gas to be recovered in the module provided with the valve.

2. The gas recovery device according to claim 1, wherein the valve opening degree of at least one of the valves decreases as the adsorption time of the gas to be recovered elapses.

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