Method for capturing carbon dioxide

Abstract

The invention relates to the technical field of carbon dioxide trapping, particularly provides a carbon dioxide trapping method, and aims to solve the problems of low trapping efficiency and high energy consumption of the existing carbon dioxide trapping method adopting a super-capacitor variable-voltage adsorption technology. In order to achieve the purpose, the carbon dioxide trapping method comprises the following steps: introducing a mixed gas containing carbon dioxide into a capacitor so as to enable the interior of the capacitor to reach a gas balance state; switching on a power supply to charge and discharge the capacitor; wherein in the process of charging and discharging the capacitor, the capacitor is firstly subjected to voltage transformation charging, then the capacitor is subjected to constant-voltage charging, and finally the capacitor is discharged. Through the arrangement, the voltage and the current can be subjected to segmented control in the charging and discharging process of the capacitor, so that the intensity of the voltage and the intensity of the current can adapt to the requirements of different stages, the adsorption efficiency and the adsorption quantity of carbon dioxide are improved, and the energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and specifically provides a method for capturing carbon dioxide. Background Art

[0002] Since excessive carbon dioxide emissions are widely considered to be the main cause of global warming and climate change, human society is facing a severe environmental problem, namely how to effectively reduce the concentration of carbon dioxide in the atmosphere.

[0003] The usual practice is to capture carbon dioxide in the atmosphere. The traditional carbon dioxide capture technology uses amine-based solvents or other solid adsorbents. This process requires an energy-intensive variable temperature regeneration process and has the disadvantages of low energy efficiency and short material life. In recent years, supercapacitor variable voltage adsorption technology has begun to be used as an electrochemical energy storage type carbon dioxide capture technology. It integrates the dual functions of supercapacitor energy storage and carbon dioxide capture, and is expected to replace the traditional high-energy consumption and high-cost organic amine solution absorption technology.

[0004] However, the existing carbon dioxide capture method using supercapacitor voltage swing adsorption technology has the problems of low capture efficiency and high energy consumption.

[0005] Therefore, this field needs a new technical solution to solve the above problems. Summary of the invention

[0006] The present invention aims to solve the above technical problem, that is, the existing carbon dioxide capture method using supercapacitor voltage swing adsorption technology has the problems of low capture efficiency and high energy consumption.

[0007] In a first aspect, the present invention provides a method for capturing carbon dioxide, which comprises the following steps: introducing a mixed gas containing carbon dioxide into a capacitor to achieve a gas equilibrium state in the capacitor; turning on a power source to charge and discharge the capacitor; wherein, in the process of charging and discharging the capacitor, the capacitor is firstly charged with a variable voltage, then charged with a constant voltage, and finally discharged.

[0008] In the preferred technical solution of the above-mentioned method for capturing carbon dioxide, the capacitor is charged and discharged multiple times.

[0009] In the preferred technical solution of the above-mentioned carbon dioxide capture method, the step of "transforming and charging the capacitor" specifically includes: performing forward transformation and charging on the capacitor.

[0010] In the preferred technical solution of the above-mentioned carbon dioxide capture method, the step of "voltage-changing charging the capacitor" specifically includes: first charging the capacitor with a first current value, then charging it with a second current value, and finally charging it with the first current value, wherein the first current value is less than the second current value.

[0011] In the preferred technical solution of the above-mentioned method for capturing carbon dioxide, the first current value is set to be no greater than 35 mA / g, and / or the second current value is set to be 40-100 mA / g.

[0012] In the preferred technical solution of the above-mentioned method for capturing carbon dioxide, the cut-off voltage of the variable voltage charging is set to be no greater than 1.25V.

[0013] In the preferred technical solution of the above-mentioned method for capturing carbon dioxide, the constant voltage charging time is set to be no more than 30 minutes.

[0014] In the preferred technical solution of the above-mentioned carbon dioxide capture method, the step of "discharging the capacitor" specifically includes: first discharging the capacitor with a third current value, then discharging with a fourth current value, and finally discharging with the third current value, wherein the third current value is smaller than the fourth current value.

[0015] In the preferred technical solution of the above-mentioned method for capturing carbon dioxide, while "charging and discharging the capacitor", the method for capturing carbon dioxide of the present invention further includes: controlling the flow rate of the mixed gas to be no greater than 0.5 CC / min.

[0016] In the preferred technical solution of the above-mentioned carbon dioxide capture method, the step of "introducing a mixed gas containing carbon dioxide into the capacitor so as to achieve a gas equilibrium state in the capacitor" specifically includes: introducing the mixed gas into the capacitor so that the concentration of carbon dioxide in the capacitor reaches a preset concentration, or introducing the mixed gas into the capacitor according to a preset time.

[0017] In the case of adopting the above technical solution, the carbon dioxide capture method of the present invention includes the following steps: introducing a mixed gas containing carbon dioxide into the capacitor to achieve a gas equilibrium state in the capacitor; connecting the power supply to charge and discharge the capacitor; wherein, in the process of charging and discharging the capacitor, the capacitor is first charged with variable voltage, then charged with constant voltage, and finally discharged. Through such a setting, on the one hand, by controlling the voltage in sections, the voltage intensity can be adjusted in time with the different stages of the carbon dioxide capture process to meet the voltage requirements of different stages, while improving the capture efficiency, it also helps to reduce energy consumption, save capture time and cost; on the other hand, it ensures the repeatability and cycle stability of the capture method, and facilitates multiple captures of carbon dioxide.

[0018] Furthermore, the capacitor is charged and discharged multiple times. This configuration is helpful to verify the cycle stability of the capture method and increase the capture amount of carbon dioxide.

[0019] Furthermore, the step of "transforming and charging the capacitor" specifically includes: forward-transforming and charging the capacitor. This arrangement helps to increase the amount of carbon dioxide adsorbed per unit time and improve the capture efficiency.

[0020] Furthermore, the step of "transformer charging the capacitor" specifically includes: first charging the capacitor with a first current value, then charging with a second current value, and finally charging with the first current value, wherein the first current value is less than the second current value. Through such a setting, it is possible to avoid large current causing excessive polarization in the initial stage of charging and affecting the capacity of the capacitor, thereby preventing the impact on the capture amount of carbon dioxide; increasing the current in the middle stage of charging is to increase the capture efficiency of carbon dioxide; reducing the current in the latter stage of charging helps to reduce energy consumption, while ensuring the adsorption efficiency of carbon dioxide, controlling the comprehensive energy consumption of the equipment.

[0021] Furthermore, the first current value of the present invention is set to be no greater than 35 mA / g, and / or the second current value is set to be 40-100 mA / g. Through such settings, a preferred solution for current control can be provided, further taking into account the capture efficiency and comprehensive energy consumption of carbon dioxide.

[0022] Furthermore, the cut-off voltage of the variable voltage charging of the present invention is set to be no more than 1.25 V. Through such a setting, the cut-off voltage can be matched with the capacitance characteristics such as the material, size and application scenario of the capacitor, while ensuring the charging and discharging efficiency, it can also prevent the capacitor from being damaged by excessively high or low voltage, thereby extending the service life of the capacitor.

[0023] Furthermore, the constant voltage charging time of the present invention is set to be no more than 30 minutes. Through such a setting, the capacity of the capacitor can be increased by constant voltage charging for a period of time, thereby increasing the carbon dioxide adsorption amount; at the same time, it also helps to extend the service life of the capacitor.

[0024] Furthermore, the step of "discharging the capacitor" specifically includes: first discharging the capacitor at a third current value, then discharging at a fourth current value, and finally discharging at a third current value, wherein the third current value is less than the fourth current value. Through such a setting, similar to the discharge process, it is possible to avoid large currents causing excessive polarization in the initial stage and affecting the capacity of the capacitor, thereby preventing the amount of carbon dioxide captured from being affected; increasing the current in the middle stage is to increase the capture efficiency of carbon dioxide; reducing the current in the latter stage helps to reduce energy consumption, while ensuring the adsorption efficiency of carbon dioxide, reducing the energy consumption of the equipment.

[0025] Furthermore, while "charging and discharging the capacitor", the carbon dioxide capture method of the present invention also includes: controlling the flow rate of the mixed gas to be no more than 0.5CC / min. This setting helps the gas in the capacitor to quickly reach a balanced state to simulate the components of various gases in industrial waste gas and the content of carbon dioxide; at the same time, it ensures that the electrode and the mixed gas can fully contact, improve the adsorption efficiency of carbon dioxide, and avoid the gas flow rate being too fast, resulting in insufficient adsorption of carbon dioxide by the capacitor.

[0026] Furthermore, the step of "introducing a mixed gas containing carbon dioxide into the capacitor so that the gas in the capacitor reaches a gas equilibrium state" specifically includes: introducing the mixed gas into the capacitor so that the concentration of carbon dioxide in the capacitor reaches a preset concentration, or introducing the mixed gas into the capacitor according to a preset time. Through such a setting, two gas introduction control methods are provided to enable the gas in the capacitor to quickly reach a balanced state. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0028] Figure 1 It is a structural schematic diagram of the capacitive adsorption device of the present invention;

[0029] Figure 2 is a flow chart of the carbon dioxide capture method of the present invention;

[0030] Figure 3 is a flow chart of an embodiment of a method for capturing carbon dioxide of the present invention;

[0031] Figure 4 is a flow chart of an embodiment of a method for capturing carbon dioxide of the present invention;

[0032] Figure 5 It is a comparison table of various specific embodiments of the carbon dioxide capture method of the present invention.

[0033] List of reference numerals:

[0034] 11. Positive electrode sheet; 12. Negative electrode sheet; 2. Shell; 21. Air inlet; 22. Air outlet; 3. Power supply; 4. Exhaust gas source; 5. Air inlet pipe; 6. Control valve. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0036] It should be noted that in the description of the present invention, the terms "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third" and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Based on the background technology, the existing carbon dioxide capture method using supercapacitor variable voltage adsorption technology has the problems of low capture efficiency and high energy consumption. The present invention provides a carbon dioxide capture method, which first introduces a mixed gas containing carbon dioxide into a capacitor to achieve a gas equilibrium state in the capacitor; then turns on the power supply to charge and discharge the capacitor; and achieves the purpose of adsorbing carbon dioxide, wherein, in the process of charging and discharging the capacitor, the capacitor is firstly charged with variable voltage, then charged with constant voltage, and finally discharged. While improving the carbon dioxide adsorption efficiency, it also helps to reduce the overall energy consumption.

[0039] The carbon dioxide capture method of the present invention adopts supercapacitor voltage-varying technology and needs to be realized by relying on the control of a capacitive adsorption device.

[0040] Specifically, Figure 1As shown, the capacitive adsorption device of the present invention includes: a capacitor, a power supply 3, an exhaust gas source 4, an intake pipe 5 and a control valve 6.

[0041] Among them, the capacitor includes a shell 2 and a positive electrode sheet 11, a negative electrode sheet 12, a diaphragm and an electrolyte arranged in the shell 2. The electrolyte is adsorbed on the diaphragm, and the diaphragm is located between the positive electrode sheet 11 and the negative electrode sheet 12 to form a supercapacitor; the positive and negative electrodes of the power supply 3 are electrically connected to the positive electrode sheet 11 and the negative electrode sheet 12 of the capacitor respectively, and the capacitor adsorbs carbon dioxide by charging and discharging the capacitor; the waste gas source 4 can be set as a container such as a gas cylinder or a gas tank, which contains a mixed gas containing carbon dioxide, and the components of various gases are adjusted to simulate industrial waste gas; the two ends of the intake pipe 5 are respectively connected to the waste gas source 4 and the capacitor to introduce the mixed gas into the capacitor to use the electrodes to adsorb carbon dioxide; the control valve 6 is installed on the intake pipe 5, and can adjust the opening of the intake pipe 5 to control the speed at which the mixed gas flows to the capacitor.

[0042] The shell 2 of the capacitor also has an air inlet 21 and an air outlet 22. The air inlet 21 is connected to the exhaust gas source 4 through the air inlet pipe 5, and the air outlet 22 is connected to a collecting device or a detecting device to process the adsorbed mixed gas.

[0043] Each functional unit can be controlled manually individually, or it can be connected to the control unit for communication and then uniformly controlled by the control unit according to a preset control program. In the present invention, the capacitive adsorption device includes a control unit, which can uniformly control the voltage intensity, current intensity, current direction of the power supply 3 and the opening of the electric control valve.

[0044] like Figure 2 and Figure 3 As shown, based on the structure of the above capacitive adsorption device, the carbon dioxide capture method provided by the present invention includes the following steps:

[0045] S100: introducing a mixed gas containing carbon dioxide into the capacitor to achieve a gas equilibrium state in the capacitor;

[0046] S200: Turn on the power supply to charge and discharge the capacitor.

[0047] The steps of charging and discharging the capacitor specifically include:

[0048] S210: transforming and charging the capacitor;

[0049] S220: charging the capacitor at a constant voltage;

[0050] S230: Discharge the capacitor.

[0051] Exemplarily, after the device is operated, the control valve 6 is first controlled to adjust the opening of the air inlet pipe 5 to a suitable position so that the mixed gas flows into the capacitor. In order to simulate the component content of industrial waste gas such as chimneys, the mixed gas in the present invention is composed of 15% carbon dioxide, 82% nitrogen and 3% oxygen. Because the capacitor is filled with air before the mixed gas is introduced, as the mixed gas is continuously introduced, the air will be discharged from the outlet 22, and the gas components in the capacitor will also change accordingly, that is, the content of the mixed gas will gradually increase, and the content of the air will gradually decrease. After continuous ventilation for a certain period of time, the mixed gas will fill the entire capacitor to achieve a balance between the internal and external air pressures and the various gas components.

[0052] It should be noted that before power is turned on, the flow rate of the mixed gas can be appropriately higher so that the capacitor can quickly reach a gas equilibrium state. After power is turned on, during the process of the electrode adsorbing carbon dioxide, the flow rate of the mixed gas should not be too high to ensure that the electrode and the mixed gas can fully contact, improve the adsorption efficiency of carbon dioxide, and prevent the gas flow rate from being too fast, resulting in insufficient adsorption of carbon dioxide by the capacitor. In this application, the flow rate of the mixed gas is preferably controlled below 0.5CC / min.

[0053] Preferably, if Figure 3 and Figure 4 As shown, while "charging and discharging the capacitor", the carbon dioxide capture method of the present invention also includes:

[0054] S300: Control the flow rate of the mixed gas to be no more than 0.5CC / min.

[0055] Whether the gas has reached a state of equilibrium can be determined by using a carbon dioxide analyzer installed in the capacitor to determine whether the concentration of carbon dioxide has reached 15%. The ventilation time required to reach a state of gas equilibrium in the capacitor can also be obtained based on experiments, such as 2 hours or 3 hours, etc. This case does not make specific limitations here.

[0056] like Figure 4 As shown, after the gas reaches a balanced state, the control power supply 3 charges and discharges the capacitor. The charging and discharging process specifically includes three stages: variable voltage charging, constant voltage charging and discharging. Among them, the step of "variable voltage charging the capacitor" specifically includes:

[0057] S211: charging the capacitor with a first current value;

[0058] S212: charging the capacitor with a second current value;

[0059] S213: Charging the capacitor with a first current value.

[0060] Specifically, during the voltage conversion charging process, the capacitor is first charged with a small current (recorded as the first current), then charged with a large current (recorded as the second current), and finally charged with a small current (recorded as the first current), wherein the first current value is smaller than the second current value.

[0061] Thus, the process of variable voltage charging is also divided into three stages in chronological order: the initial stage, the middle stage and the final stage. In the present invention, the charging current (first current value) of the initial stage and the final stage is preferably set to no more than 35mA / g, and further preferably set to 30mA / g; the charging current (second current value) of the middle stage is preferably set to 40-100mA / g, and further preferably set to 75mA / g. Among them, the remaining capacity (SOC) of the capacitor is used as the dividing point of the initial stage, the middle stage and the final stage. Specifically, in the actual charging process, the power supply 3 first charges the SOC of the capacitor from 0 to 60% with the first current value, then charges the SOC of the capacitor from 60% to 80% with the second current value, and finally charges the SOC of the capacitor from 80% to 100% with the first current value.

[0062] By controlling the current in segments, it is possible to prevent excessive current from causing excessive polarization in the initial stage of charging, thereby affecting the capacity of the capacitor and avoiding affecting the amount of carbon dioxide captured; increasing the current in the middle stage of charging is to increase the carbon dioxide capture efficiency; reducing the current in the latter stage helps to reduce energy consumption, thereby ensuring the adsorption efficiency of carbon dioxide while reducing equipment energy consumption.

[0063] After the variable voltage charging process is completed, the control power supply 3 enters the constant voltage charging process, wherein the cut-off voltage of the variable voltage charging is set to no more than 1.25V, that is, when the voltage of the capacitor reaches 1.25V, it enters the constant voltage charging process, and the constant voltage charging voltage is consistent with the cut-off voltage. The constant voltage charging time is preferably set to no more than 30min. The cut-off voltage of the present invention is preferably set to 0.9V, and the constant voltage charging time is preferably set to 6min.

[0064] Through the constant voltage charging process, on the one hand, the capacity of the capacitor can be increased, thereby increasing the amount of carbon dioxide adsorption; on the other hand, it also helps to extend the service life of the capacitor, especially during the high current charging and discharging process, which will cause excessive decomposition of water and lead to damage to the capacitor.

[0065] It should be noted that the charging modes include positive charging (positive voltage charging, charging from the equilibrium voltage to the positive voltage direction (+)), negative charging (negative charging, charging from the equilibrium voltage to the negative voltage (-)) and conversion charging (i.e., charging by switching between positive and negative voltages). The present invention preferably adopts positive charging, which can further increase the adsorption amount of carbon dioxide per unit time and improve the capture efficiency compared with negative charging and conversion charging.

[0066] After the constant voltage charging process is completed, the capacitor adsorption device is controlled to enter the discharge process. The discharge process also adopts the method of segmented control of the discharge current, that is, the capacitor is first discharged with a third current value, then discharged with a fourth current value, and finally charged with the third current value, wherein the third current value is less than the fourth current value. In the discharge process of the present invention, the third current value is preferably set to no more than 35mA / g, and further preferably set to 30mA / g; the fourth current value is preferably set to 40-100mA / g, and further preferably set to 75mA / g. Through such a setting, it also plays a role in balancing the capture efficiency and controlling the energy consumption.

[0067] It should be noted that the above control process can be repeatedly cycled to adjust the absorption amount of carbon dioxide as needed.

[0068] The carbon dioxide capture method of the present invention is described in detail below in combination with a plurality of specific embodiments, and the description of the following embodiments is only used to help understand the present invention. It should be pointed out that for those skilled in the art, the present invention can also be adjusted and improved to a certain extent without departing from the principle of the present invention, and these adjustments and improvements will also fall within the scope of protection of the claims of the present invention.

[0069] In a first preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0070] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0071] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0072] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0073] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0074] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0075] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0076] Repeat the above steps 1000 times.

[0077] In a second preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0078] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.05CC / min;

[0079] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0080] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0081] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0082] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0083] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0084] Repeat the above steps 1000 times.

[0085] In a third preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0086] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.5CC / min;

[0087] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0088] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0089] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0090] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0091] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0092] Repeat the above steps 1000 times.

[0093] In a fourth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0094] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0095] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0096] The supercapacitor adopts negative charging mode, that is, charging from 0V to -0.9V;

[0097] The supercapacitor was charged to 60% SOC (about -0.55V) at a current density of 30mA / g, then to 80% SOC (about -0.73V) at a current density of 75mA / g, and then to 100% SOC (-0.9V) at a current density of 30mA / g.

[0098] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0099] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about -0.35 V), then at a current density of 75 mA / g to 20% SOC (about -0.17 V), and then at a current density of 30 mA / g to 0% SOC (-0 V);

[0100] Repeat the above steps 1000 times.

[0101] In a fifth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0102] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0103] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0104] The supercapacitor adopts conversion charging mode, that is, charging from -0.9V to 0.9V;

[0105] The supercapacitor was charged to 60% SOC (about 0.18V) at a current density of 30mA / g, then to 80% SOC (about 0.54V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0106] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0107] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.18 V), then at a current density of 75 mA / g to 20% SOC (about -0.54 V), and then at a current density of 30 mA / g to 0% SOC (-0.9 V);

[0108] Repeat the above steps 1000 times.

[0109] In a sixth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0110] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0111] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0112] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0113] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 10mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 10mA / g.

[0114] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0115] The supercapacitor was discharged at a current density of 10 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 10 mA / g to 0% SOC (0 V);

[0116] Repeat the above steps 1000 times.

[0117] In a seventh preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0118] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0119] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0120] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0121] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0122] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0123] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0124] Repeat the above steps 1000 times.

[0125] In an eighth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0126] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0127] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0128] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0129] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 35mA / g, then to 80% SOC (about 0.73V) at a current density of 40mA / g, and then to 100% SOC (0.9V) at a current density of 35mA / g.

[0130] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0131] The supercapacitor was discharged at a current density of 35 mA / g to 60% SOC (about 0.35 V), then at a current density of 40 mA / g to 20% SOC (about 0.17 V), and then at a current density of 35 mA / g to 0% SOC (0 V);

[0132] Repeat the above steps 1000 times.

[0133] In a ninth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0134] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0135] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0136] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0137] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 35mA / g, then to 80% SOC (about 0.73V) at a current density of 100mA / g, and then to 100% SOC (0.9V) at a current density of 35mA / g.

[0138] The supercapacitor maintains a constant voltage of about 0.9V for 6 minutes;

[0139] The supercapacitor was discharged at a current density of 35 mA / g to 60% SOC (about 0.35 V), then at a current density of 100 mA / g to 20% SOC (about 0.17 V), and then at a current density of 35 mA / g to 0% SOC (0 V);

[0140] Repeat the above steps 1000 times.

[0141] In a tenth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0142] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0143] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0144] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0145] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0146] The supercapacitor is kept at a constant voltage of about 0.5V for 6 minutes;

[0147] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0148] Repeat the above steps 1000 times.

[0149] In an eleventh preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0150] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0151] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0152] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0153] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0154] The supercapacitor is kept at a constant voltage of about 1.25V for 6 minutes;

[0155] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0156] Repeat the above steps 1000 times.

[0157] In a twelfth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0158] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0159] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0160] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0161] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0162] The supercapacitor maintains a constant voltage of about 0.9V for 0min;

[0163] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0164] Repeat the above steps 1000 times.

[0165] In a thirteenth preferred embodiment, the method for capturing carbon dioxide of the present invention specifically comprises:

[0166] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0167] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0168] The supercapacitor adopts the forward charging mode, that is, charging from 0V to 0.9V;

[0169] The supercapacitor was charged to 60% SOC (about 0.55V) at a current density of 30mA / g, then to 80% SOC (about 0.73V) at a current density of 75mA / g, and then to 100% SOC (0.9V) at a current density of 30mA / g.

[0170] The supercapacitor maintains a constant voltage of about 0.9V for 30 minutes;

[0171] The supercapacitor was discharged at a current density of 30 mA / g to 60% SOC (about 0.35 V), then at a current density of 75 mA / g to 20% SOC (about 0.17 V), and then at a current density of 30 mA / g to 0% SOC (0 V);

[0172] Repeat the above steps 1000 times.

[0173] In addition, a prior art is provided as a comparative example, and the specific steps are as follows:

[0174] Continue to introduce the mixed gas into the capacitor device at a flow rate of 0.15CC / min;

[0175] Fill the capacitor with mixed gas and balance the internal and external pressures. Observe the carbon dioxide concentration at 15% using a carbon dioxide analyzer.

[0176] The supercapacitor was charged at 0.9 V at a current density of 30 mA / g;

[0177] The supercapacitor was discharged to 0 V at a current density of 30 mA / g;

[0178] Repeat the above steps 1000 times;

[0179] like Figure 5 As shown, in different embodiments, a comparison table of the adsorption amount of carbon dioxide per unit time is obtained by sequentially adjusting the parameters such as the flow rate of the mixed gas, the charging direction, the current density during charging and discharging, the voltage intensity during constant voltage charging, and the time of constant voltage charging. The optimal value of each variable can be obtained through the comparison table:

[0180] By comparing Example 1, Example 2 and Example 3, it is found that when the flow rate is 0.15CC / min, the initial capacity of the capacitor, the amount of carbon dioxide adsorbed, the energy consumption, the amount of adsorption per unit time, and the capacity retention rate after 1000 cycles are optimal, indicating that too large or too small a flow rate will lead to incomplete carbon dioxide adsorption, which will ultimately increase its economic cost.

[0181] By comparing Example 1, Example 4 and Example 5, it is found that the comprehensive performance is excellent during forward charging. Although the initial capacity and carbon dioxide adsorption capacity of the capacitor during conversion charging are much higher than those during forward charging, this is at the expense of energy consumption. The comprehensive economic cost is higher than that of forward charging. The initial capacity, carbon dioxide adsorption capacity, energy consumption and adsorption capacity per unit time of the negative charging capacitor are not much different from those of the positive charging, but the cycle stability is poor.

[0182] By comparing Example 1, Example 6 and Example 7, it is found that the performance is most excellent when the small current is 30 mA / g. Too small current will affect the adsorption amount per unit time, and too large current will cause a decrease in initial capacity and carbon dioxide adsorption amount.

[0183] By comparing Example 1, Example 8 and Example 9, it is found that the performance is best when the large current is 75 mA / g. If the large current is too small, it will affect the adsorption amount per unit time, and if the large current is too large, the initial capacity and the carbon dioxide adsorption amount will be reduced.

[0184] By comparing Example 1, Example 10 and Example 11, it is found that the performance is best when the voltage is 0.9V. If the voltage is too low, the initial capacity of the capacitor and the adsorption amount of carbon dioxide will be too low. If the voltage is too high, the performance of the capacitor will be degraded and the cycle performance will be poor.

[0185] By comparing Example 1, Example 12 and Example 13, it is found that the performance is best when the voltage is maintained for 6 minutes. If the time is too short, the energy efficiency is low, but the capacity and carbon dioxide adsorption amount are too low; if the time is too long, it will cause excessive energy consumption.

[0186] By comparing Example 1 and the comparative example, it is found that the performance is most excellent when the voltage is maintained for 6 minutes. By constant voltage charging, the initial capacity, the adsorption amount of carbon dioxide and the capacity retention rate after 1000 cycles can be greatly improved.

[0187] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for capturing carbon dioxide, characterized in that: The carbon dioxide capture method comprises the following steps: Introducing a mixed gas containing carbon dioxide into the capacitor so that a gas equilibrium state is reached in the capacitor; Turning on the power supply to charge and discharge the capacitor; In the process of charging and discharging the capacitor, the capacitor is first charged with a variable voltage, then charged with a constant voltage, and finally discharged.

2. The method for capturing carbon dioxide according to claim 1, characterized in that: The capacitor is charged and discharged multiple times.

3. The method for capturing carbon dioxide according to claim 1, characterized in that: The step of "transforming and charging the capacitor" specifically includes: The capacitor is charged by forward voltage transformation.

4. The method for capturing carbon dioxide according to claim 1, characterized in that: The step of "transforming and charging the capacitor" specifically includes: The capacitor is first charged with a first current value, then charged with a second current value, and finally charged with the first current value, wherein the first current value is smaller than the second current value.

5. The method for capturing carbon dioxide according to claim 4, characterized in that: The first current value is set to be no greater than 35 mA / g, and / or The second current value is set to 40-100 mA / g.

6. The method for capturing carbon dioxide according to any one of claims 1 to 5, characterized in that: The cut-off voltage of the variable voltage charging is set to be no greater than 1.25V.

7. The method for capturing carbon dioxide according to any one of claims 1 to 5, characterized in that: The constant voltage charging time is set to be no more than 30 minutes.

8. The method for capturing carbon dioxide according to any one of claims 1 to 5, characterized in that: The step of "discharging the capacitor" specifically includes: The capacitor is first discharged with a third current value, then discharged with a fourth current value, and finally discharged with the third current value, wherein the third current value is smaller than the fourth current value.

9. The method for capturing carbon dioxide according to claim 1, characterized in that: While "charging and discharging the capacitor", the carbon dioxide capture method of the present invention further comprises: The flow rate of the mixed gas is controlled to be no greater than 0.5 CC / min.

10. The method for capturing carbon dioxide according to claim 1 or 9, characterized in that: The step of "introducing a mixed gas containing carbon dioxide into the capacitor so as to achieve a gas equilibrium state in the capacitor" specifically includes: introducing the mixed gas into the capacitor so that the concentration of carbon dioxide in the capacitor reaches a preset concentration, or The mixed gas is introduced into the capacitor according to a preset time.

Images