A method and system for enriching biogenic carbon isotopes in combustion flue gas

Abstract

The present invention relates to the technical field of carbon enrichment, and discloses a method and system for enriching biogenic carbon isotopes in combustion flue gas. The method comprises: filtering the combustion flue gas, sequentially passing it through a compressor and an air inlet valve into an adsorption tower, and then passing it through an air outlet valve and a vacuum pump into a carbon isotope collection tank; during adsorption, obtaining the real-time temperature and real-time pressure of the adsorption tower, and determining a preset pressure of the adsorption tower based on the real-time temperature; determining the pressure difference between the real-time temperature and the real-time pressure, and determining the compression power adjustment of the compressor based on the pressure difference; during desorption, obtaining a first real-time carbon dioxide concentration in the adsorption tower, determining a desorption start time based on the first real-time carbon dioxide concentration, and obtaining a second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank, and setting the operating power of the vacuum pump based on the second real-time carbon dioxide concentration to achieve carbon isotope enrichment. This method improves the extraction efficiency and purity of carbon isotopes and reduces operating costs.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon enrichment, and in particular to a method and system for enriching biogenic carbon isotopes in combustion flue gas. Background Art

[0002] As a common method of waste disposal, waste incineration produces a large amount of gas emissions during the treatment process. These gases contain a large amount of CO2. General waste includes both biofuels and fossil fuels. Among them, there is a difference in the carbon element in the CO2 produced by the combustion of biofuels such as wood, straw and other plant materials, and fossil fuels such as coal, oil and natural gas. The carbon element of CO2 after the combustion of biofuels is 14C, and the carbon element of CO2 after the combustion of fossil fuels is 13C or 12C. The CO2 after the combustion of biofuels can be absorbed by new plant growth, thereby reducing the increase in net CO2 in the atmosphere. The CO2 after the combustion of fossil fuels directly adds new CO2 to the atmosphere. This CO2 has been "fixed" in the earth's crust for millions of years, and has an immediate effect on increasing the CO2 concentration in the atmosphere.

[0003] Therefore, accurately determining the 14C-containing carbon dioxide content in waste incineration flue gas can reduce greenhouse gas emissions and improve air quality. Carbon isotope enrichment is a key step in this process. Traditional enrichment methods, such as chemical absorption or cryogenic separation, involve extracting carbon isotopes from flue gas, which is extremely costly and unsuitable for large-scale application.

[0004] Therefore, it is particularly important to invent a method and system for enriching biogenic carbon isotopes in combustion flue gas. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for enriching biogenic carbon isotopes in combustion flue gas, so as to solve the problems of extremely high cost and easy generation of other gases during the desorption process of traditional enrichment methods such as chemical absorption or low-temperature separation.

[0006] The present invention provides a method for enriching biogenic carbon isotopes in combustion flue gas, the method comprising:

[0007] The combustion flue gas is filtered, and the filtered combustion flue gas is sequentially passed through a compressor and an air inlet valve into an adsorption tower, and then passed through an air outlet valve and a vacuum pump into a carbon isotope collection tank;

[0008] During adsorption, obtaining the real-time temperature and real-time pressure of the adsorption tower, determining the preset pressure of the adsorption tower according to the real-time temperature; determining the pressure difference between the preset pressure and the real-time pressure, and determining the compression power adjustment amount of the compressor according to the pressure difference;

[0009] During desorption, the first real-time carbon dioxide concentration of the adsorption tower is obtained, and whether to start desorption is determined based on the first real-time carbon dioxide concentration. If desorption starts, the second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank is obtained, and the working power of the vacuum pump is set according to the second real-time carbon dioxide concentration to achieve enrichment of carbon isotopes.

[0010] Preferably, during adsorption, the air inlet valve is opened to allow the filtered combustion flue gas to flow into the adsorption tower, and the compressor is turned on to compress the combustion flue gas in the adsorption tower, while the air outlet valve and the vacuum pump are closed.

[0011] Preferably, during desorption, the air inlet valve and the compressor are closed, the air outlet valve is opened, and the vacuum pump is turned on to evacuate the adsorption tower.

[0012] Preferably, determining the preset pressure of the adsorption tower according to the real-time temperature includes:

[0013] Presetting a first preset temperature, a second preset temperature, and a third preset temperature, wherein the first preset temperature, the second preset temperature, and the third preset temperature increase in sequence;

[0014] Setting a preset pressure P of the adsorption tower according to a relationship between the real-time temperature and the first preset temperature, the second preset temperature, and the third preset temperature;

[0015] If the real-time temperature is lower than the first preset temperature, the preset pressure P of the adsorption tower is set to the first preset pressure P1, that is, P=P1;

[0016] If the real-time temperature is greater than or equal to the first preset temperature and the real-time temperature is less than the second preset temperature, the preset pressure P of the adsorption tower is set to the second preset pressure P2, that is, P=P2;

[0017] If the real-time temperature is greater than or equal to the second preset temperature and is less than the third preset temperature, the preset pressure P of the adsorption tower is set to the third preset pressure P3, that is, P=P3;

[0018] If the real-time temperature is greater than or equal to the third preset temperature, the preset pressure P of the adsorption tower is set to a fourth preset pressure P4, that is, P=P4; wherein P1>P2>P3>P4.

[0019] Preferably, determining the pressure difference between the preset pressure and the real-time pressure, and determining the compression power adjustment amount of the compressor according to the pressure difference, comprises:

[0020] Set the real-time pressure to P0, and determine the pressure difference Pc between the preset pressure P and the real-time pressure P0, Pc=P-P0;

[0021] Presetting a first pressure difference value, a second pressure difference value, and a third pressure difference value, wherein the first pressure difference value, the second pressure difference value, and the third pressure difference value increase in sequence;

[0022] setting a compression power adjustment amount A of the compressor according to a relationship between the pressure difference value Pc and the first pressure difference value, the second pressure difference value, and the third pressure difference value;

[0023] If the pressure difference Pc is less than the first pressure difference, the compression power adjustment amount A of the compressor is set to the first compression power adjustment amount A1, that is, A=A1;

[0024] If the pressure difference Pc is greater than or equal to the first pressure difference, and the pressure difference Pc is less than the second pressure difference, the compression power adjustment amount A of the compressor is set to the second compression power adjustment amount A2, that is, A=A2;

[0025] If the pressure difference Pc is greater than or equal to the second pressure difference, and the pressure difference Pc is less than the third pressure difference, the compression power adjustment amount A of the compressor is set to the third compression power adjustment amount A3, that is, A=A3;

[0026] If the pressure difference Pc is greater than or equal to the third pressure difference, the compression power adjustment amount A of the compressor is set to the fourth compression power adjustment amount A4, that is, A=A4; wherein A1<A2<A3<A4.

[0027] Preferably, determining whether to start desorption according to the first real-time carbon dioxide concentration includes:

[0028] Determine the concentration difference Cc between the first real-time carbon dioxide concentration at time t and the first real-time carbon dioxide concentration at time t-1, that is, Cc=C t -C t-1 ;

[0029] When the concentration difference Cc is equal to 0, it is determined that desorption begins.

[0030] Preferably, setting the operating power of the vacuum pump according to the second real-time carbon dioxide concentration includes:

[0031] Pre-set CO2 concentration thresholds;

[0032] determining a carbon dioxide concentration difference between the carbon dioxide concentration threshold and the second real-time carbon dioxide concentration, and setting an operating power of the vacuum pump according to the carbon dioxide concentration difference;

[0033] presetting a first carbon dioxide concentration difference value, a second carbon dioxide concentration difference value, and a third carbon dioxide concentration difference value, wherein the first carbon dioxide concentration difference value, the second carbon dioxide concentration difference value, and the third carbon dioxide concentration difference value increase in sequence;

[0034] setting a working efficiency W of the vacuum pump according to a relationship between the carbon dioxide concentration difference and the first carbon dioxide concentration difference, the second carbon dioxide concentration difference, and the third carbon dioxide concentration difference;

[0035] If the carbon dioxide concentration difference is less than the first carbon dioxide concentration difference, the working efficiency W of the vacuum pump is set to the first preset working efficiency W1, that is, W=W1;

[0036] If the carbon dioxide concentration difference is greater than or equal to the first carbon dioxide concentration difference, and the carbon dioxide concentration is less than the second carbon dioxide concentration, the working efficiency W of the vacuum pump is set to a second preset working efficiency W2, that is, W=W2;

[0037] If the carbon dioxide concentration difference is greater than or equal to the second carbon dioxide concentration difference, and the carbon dioxide concentration is less than the third carbon dioxide concentration, the working efficiency W of the vacuum pump is set to a third preset working efficiency W3, that is, W=W3;

[0038] If the carbon dioxide concentration difference is greater than or equal to the third carbon dioxide concentration difference, the working efficiency W of the vacuum pump is set to a fourth preset working efficiency W4, that is, W=W4; wherein W1<W2<W3<W4.

[0039] Preferably, the adsorption tower is connected to a second air outlet valve. After the adsorption is completed and before the desorption begins, the air inlet valve is closed and the second air outlet valve is opened to release the combustion flue gas after the adsorption in the adsorption tower.

[0040] The present invention also discloses a system for enriching biogenic carbon isotopes in combustion flue gas, which is used to apply the above-mentioned method for enriching biogenic carbon isotopes in combustion flue gas. The system comprises:

[0041] an acquisition module, the acquisition module being used to acquire the real-time temperature and real-time pressure of the adsorption tower, and to acquire a first real-time carbon dioxide concentration of the adsorption tower and a second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank;

[0042] an adsorption control module, the adsorption control module being configured to determine a preset pressure of the adsorption tower according to the real-time temperature; and to determine a pressure difference between the preset pressure and the real-time pressure, and to determine a compression power adjustment amount of the compressor according to the pressure difference;

[0043] A desorption control module is used to determine whether to start desorption according to the first real-time carbon dioxide concentration. If desorption is started, the operating power of the vacuum pump is set according to the second real-time carbon dioxide concentration to achieve enrichment of carbon isotopes.

[0044] Preferably, the adsorption control module is further used to control the air inlet valve; the desorption control module is further used to control the air outlet valve.

[0045] Compared with the prior art, the beneficial effect of the present invention is that the present invention discloses a method and system for enriching biogenic carbon isotopes in combustion flue gas, wherein the filtered combustion flue gas is passed into an adsorption tower for adsorption and desorption, making the enrichment device easy to control; during the adsorption process, the optimal adsorption pressure is determined by detecting the real-time temperature and real-time pressure, and the pressure in the adsorption tower is adjusted by controlling the compressor to ensure that it reaches the optimal adsorption pressure, thereby improving the adsorption efficiency; at the same time, the carbon dioxide concentration in the adsorption tower is detected to determine whether the adsorption is completed, and desorption is started, low-pressure desorption is achieved by controlling the vacuum pump, and the desorbed carbon dioxide is enriched to achieve carbon isotope enrichment. According to the data changes in the enrichment process, each link is intelligently controlled, thereby improving the extraction efficiency and purity of carbon isotopes, solving the high energy consumption problem in traditional methods, and reducing operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0047] Figure 1 This is a schematic flow chart of a method for enriching biogenic carbon isotopes in combustion flue gas according to the present invention;

[0048] Figure 2 is a schematic structural diagram of a carbon isotope enrichment device according to an embodiment of the present invention;

[0049] Figure 3 This is a functional block diagram of a system for enriching biogenic carbon isotopes in combustion flue gas according to the present invention.

[0050] Among them, 1. Adsorption tower; 2. Compressor; 3. Air inlet valve; 4. Air outlet valve; 5. Vacuum pump; 6. Carbon isotope collection tank; 7. Second air outlet valve. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0055] like Figure 1 As shown, the present invention provides a method for enriching biogenic carbon isotopes in combustion flue gas, the method comprising:

[0056] S1, the combustion flue gas is filtered, and the filtered combustion flue gas is sequentially passed through the compressor and the air inlet valve into the adsorption tower, and then passes through the air outlet valve and the vacuum pump into the carbon isotope collection tank.

[0057] S2, during adsorption, obtain the real-time temperature and real-time pressure of the adsorption tower, determine the preset pressure of the adsorption tower according to the real-time temperature; determine the pressure difference between the preset pressure and the real-time pressure, and determine the compression power adjustment amount of the compressor according to the pressure difference.

[0058] S3, when desorption occurs, obtain the first real-time carbon dioxide concentration of the adsorption tower, determine whether to start desorption based on the first real-time carbon dioxide concentration, and if desorption starts, obtain the second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank, and set the working power of the vacuum pump based on the second real-time carbon dioxide concentration to achieve carbon isotope enrichment.

[0059] In some embodiments of the present application, during adsorption, the air inlet valve is opened to pass the filtered combustion flue gas into the adsorption tower, and the compressor is turned on to compress the combustion flue gas in the adsorption tower, while the air outlet valve and vacuum pump are closed.

[0060] In this embodiment, the air inlet valve is opened to allow the filtered combustion flue gas to enter the adsorption tower. While the air inlet valve is open, it is necessary to start the compressor to compress the combustion flue gas entering the adsorption tower to increase the flue gas concentration and thus improve the adsorption effect. During the compression process, it should be ensured that the air outlet valve and the vacuum pump are in the closed state. The closing of the air outlet valve is to prevent the flue gas in the adsorption tower from leaking, so as not to affect the adsorption effect. At the same time, the vacuum pump is turned off to avoid unnecessary energy consumption during the adsorption process. In the adsorption tower, the combustion flue gas passes through the adsorbent, and the carbon dioxide therein is effectively adsorbed. After a certain period of adsorption treatment, the adsorbent in the adsorption tower will reach a saturated state, and the adsorption will stop at this time.

[0061] In some embodiments of the present application, during desorption, the air inlet valve and the compressor are closed, the air outlet valve is opened, and the vacuum pump is turned on to evacuate the adsorption tower.

[0062] In this embodiment, the main purpose of the desorption process is to release the target substance adsorbed in the tower from the adsorbent for subsequent analysis and processing. The air inlet valve and compressor are closed because they serve to transport gas during the adsorption process, but they are not required during the desorption process. Closing the air inlet valve and compressor prevents gas from entering the adsorption tower during the desorption process, thereby ensuring the smooth progress of the desorption process. Next, the air outlet valve is opened. The function of the air outlet valve is to allow the desorbed gas to be discharged from the adsorption tower. During the desorption process, the target substance on the adsorbent is released. Opening the air outlet valve allows this gas to be smoothly discharged from the adsorption tower, creating conditions for subsequent operations. Finally, the vacuum pump is turned on to evacuate the adsorption tower. The function of the vacuum pump is to extract the gas from the adsorption tower, creating a vacuum state within the adsorption tower. In a vacuum state, the target substance on the adsorbent is more easily desorbed, thereby improving the desorption efficiency.

[0063] In some embodiments of the present application, determining the preset pressure of the adsorption tower according to the real-time temperature includes: presetting a first preset temperature, a second preset temperature, and a third preset temperature, the first preset temperature, the second preset temperature, and the third preset temperature increasing in sequence; setting the preset pressure P of the adsorption tower according to the relationship between the real-time temperature and the first preset temperature, the second preset temperature, and the third preset temperature; if the real-time temperature is less than the first preset temperature, setting the preset pressure P of the adsorption tower to the first preset pressure P1, that is, P=P1; if the real-time temperature is greater than or equal to the first preset temperature and the real-time temperature is less than the second preset temperature, setting the preset pressure P of the adsorption tower to the second preset pressure P2, that is, P=P2; if the real-time temperature is greater than or equal to the second preset temperature and the real-time temperature is less than the third preset temperature, setting the preset pressure P of the adsorption tower to the third preset pressure P3, that is, P=P3; if the real-time temperature is greater than or equal to the third preset temperature, setting the preset pressure P of the adsorption tower to the fourth preset pressure P4, that is, P=P4; wherein, P1>P2>P3>P4.

[0064] In this embodiment, during the adsorption process, temperature and pressure have a significant effect on the adsorption performance of carbon dioxide. The present invention adopts physical adsorption, which is a technology for separating carbon dioxide from a mixed gas by means of a solid adsorbent. Its basic principle is to use the van der Waals force between the gas and the solid adsorbent to achieve adsorption. As the temperature rises, the average kinetic energy of the gas molecules increases, so that more molecules can overcome the adsorption force and leave the solid surface, resulting in a decrease in the adsorption amount. As the pressure increases, the number of collisions between the gas molecules and the surface of the solid adsorbent increases, thereby increasing the adsorption amount. Under high pressure conditions, physical adsorption is more significant because high pressure is conducive to the accumulation of gas molecules on the adsorbent surface. Therefore, by setting the preset pressure according to the relationship between the real-time temperature and the preset temperature, the adsorption tower achieves the best adsorption efficiency. According to the effect of temperature and pressure on the adsorption efficiency, it can be determined that the higher the temperature, the greater the required pressure should be.

[0065] In some embodiments of the present application, a pressure difference between a preset pressure and a real-time pressure is determined, and a compression power adjustment amount of the compressor is determined according to the pressure difference, including: setting the real-time pressure to P0, determining a pressure difference Pc between the preset pressure P and the real-time pressure P0, where Pc=P-P0; presetting a first pressure difference, a second pressure difference, and a third pressure difference, wherein the first pressure difference, the second pressure difference, and the third pressure difference increase in sequence; setting a compression power adjustment amount A of the compressor according to a relationship between the pressure difference Pc and the first pressure difference, the second pressure difference, and the third pressure difference; if the pressure difference Pc is less than the first pressure difference, setting the compression power adjustment amount A of the compressor A is the first compression power adjustment amount A1, that is, A=A1; if the pressure difference Pc is greater than or equal to the first pressure difference, and the pressure difference Pc is less than the second pressure difference, then the compression power adjustment amount A of the compressor is set to the second compression power adjustment amount A2, that is, A=A2; if the pressure difference Pc is greater than or equal to the second pressure difference, and the pressure difference Pc is less than the third pressure difference, then the compression power adjustment amount A of the compressor is set to the third compression power adjustment amount A3, that is, A=A3; if the pressure difference Pc is greater than or equal to the third pressure difference, then the compression power adjustment amount A of the compressor is set to the fourth compression power adjustment amount A4, that is, A=A4; wherein, A1<A2<A3<A4.

[0066] In this embodiment, the pressure difference between the preset pressure and the real-time pressure is determined, and the compression power adjustment amount of the compressor is determined based on the pressure difference. The pressure in the adsorption tower is changed by the operation of the compressor so that the pressure in the adsorption tower reaches the preset pressure to achieve more efficient adsorption.

[0067] In some embodiments of the present application, determining whether to start desorption according to the first real-time carbon dioxide concentration includes: determining a concentration difference Cc between the first real-time carbon dioxide concentration at time t and the first real-time carbon dioxide concentration at time t-1, that is, Cc=C t -C t-1 ; When the concentration difference Cc is equal to 0, it is determined that desorption begins.

[0068] In this embodiment, the carbon dioxide concentration is highest when the filtered combustion flue gas first enters the adsorption tower. As the adsorbent absorbs carbon dioxide, the carbon dioxide concentration in the adsorption tower gradually decreases until the adsorbent reaches saturation. Once the adsorbent reaches saturation, the carbon dioxide concentration in the adsorption tower no longer changes. Therefore, by determining whether the concentration difference Cc between the first real-time carbon dioxide concentration at time t and the first real-time carbon dioxide concentration at time t-1 is zero, it is determined whether the adsorbent is saturated and whether desorption needs to begin.

[0069] In some embodiments of the present application, the operating power of the vacuum pump is set according to the second real-time carbon dioxide concentration, including: presetting a carbon dioxide concentration threshold; determining a carbon dioxide concentration difference between the carbon dioxide concentration threshold and the second real-time carbon dioxide concentration, and setting the operating power of the vacuum pump according to the carbon dioxide concentration difference; presetting a first carbon dioxide concentration difference, a second carbon dioxide concentration difference, and a third carbon dioxide concentration difference, the first carbon dioxide concentration difference, the second carbon dioxide concentration difference, and the third carbon dioxide concentration difference increasing in sequence; setting the operating efficiency W of the vacuum pump according to the relationship between the carbon dioxide concentration difference and the first carbon dioxide concentration difference, the second carbon dioxide concentration difference, and the third carbon dioxide concentration difference; if the carbon dioxide concentration difference is less than the first and second carbon dioxide concentration differences, the operating power of the vacuum pump is set .... If the carbon dioxide concentration difference is greater than or equal to the first carbon dioxide concentration difference, and the carbon dioxide concentration is less than the second carbon dioxide concentration, the working efficiency W of the vacuum pump is set to the second preset working efficiency W2, that is, W=W2; if the carbon dioxide concentration difference is greater than or equal to the second carbon dioxide concentration difference, and the carbon dioxide concentration is less than the third carbon dioxide concentration, the working efficiency W of the vacuum pump is set to the third preset working efficiency W3, that is, W=W3; if the carbon dioxide concentration difference is greater than or equal to the third carbon dioxide concentration difference, the working efficiency W of the vacuum pump is set to the fourth preset working efficiency W4, that is, W=W4; wherein, W1<W2<W3<W4.

[0070] In some embodiments of the present application, the adsorption tower is connected to a second air outlet valve. After adsorption is completed and before desorption begins, the air inlet valve is closed and the second air outlet valve is opened to release the combustion flue gas after adsorption in the adsorption tower.

[0071] In this embodiment, the gas inside the adsorption tower remains at high pressure after the adsorption process is complete. To reduce the internal pressure of the adsorption tower to atmospheric pressure, while also reducing energy consumption and alleviating the workload of the vacuum pump, a second outlet valve is provided. This second outlet valve allows the gas inside the adsorption tower to naturally escape, maintaining a constant pressure inside the tower. This improvement not only helps reduce the accumulation of residual gas in the adsorption tower along with the high-concentration carbon dioxide after desorption, but also reduces the workload of the vacuum pump, thereby reducing energy consumption.

[0072] Furthermore, by incorporating a second outlet valve, the adsorption tower automatically adjusts during operation, stabilizing the air pressure within the optimal operating range. This helps ensure the stability and continuity of the adsorption effect, improving overall operational efficiency. This approach also reduces equipment failure rates, extends equipment life, and saves costs.

[0073] like Figure 2As shown, to further illustrate the enrichment method of the present invention, the present application discloses a carbon isotope enrichment device, comprising an adsorption tower 1, a compressor 2, an air inlet valve 3, an air outlet valve 4, a vacuum pump 5, a carbon isotope collection tank 6, and a second air outlet valve 7. The compressor 2, the air inlet valve 3, the adsorption tower 1, the air outlet valve 4, the vacuum pump 5, and the carbon isotope collection tank 6 are connected in sequence, and the adsorption tower 1 is also connected to the second air outlet valve 7. When adsorption is performed, the air inlet valve 3 and the compressor 2 are opened, and the air outlet valve 4, the vacuum pump 5, and the second air outlet valve 7 are closed. After the adsorption is completed, before desorption begins, the second air outlet valve 7 is opened, and the air inlet valve 3, the compressor 2, the air outlet valve 4, and the vacuum pump 5 are closed. When desorption begins, the air outlet valve 4 and the vacuum pump 5 are opened, and the air inlet valve 3, the compressor 2, and the second air outlet valve 7 are closed.

[0074] The present invention also discloses a system for enriching biogenic carbon isotopes in combustion flue gas, which is used to apply the above-mentioned method for enriching biogenic carbon isotopes in combustion flue gas, such as Figure 3 As shown, the system includes:

[0075] The acquisition module is used to obtain the real-time temperature and real-time pressure of the adsorption tower, and to obtain the first real-time carbon dioxide concentration of the adsorption tower and the second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank.

[0076] The adsorption control module is used to determine the preset pressure of the adsorption tower according to the real-time temperature; and determine the pressure difference between the preset pressure and the real-time pressure, and determine the compression power adjustment amount of the compressor according to the pressure difference.

[0077] The desorption control module is used to determine whether to start desorption according to the first real-time carbon dioxide concentration. If desorption starts, the working power of the vacuum pump is set according to the second real-time carbon dioxide concentration to achieve enrichment of carbon isotopes.

[0078] In some embodiments of the present application, the adsorption control module is further used to control the air inlet valve; and the desorption control module is further used to control the air outlet valve.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

[0080] The system provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiment can be combined into one module or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps and are not to be regarded as improper limitations of the present invention.

[0081] Those skilled in the art should be able to appreciate that, in conjunction with the modules and method steps of each example described in the embodiments disclosed herein, it is possible to implement them with electronic hardware, computer software, or a combination of the two, and the programs corresponding to the software modules and method steps can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, AD-ROMs, or any other form of storage medium known in the art. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

Claims

1. A method for enriching biogenic carbon isotopes in combustion flue gas, characterized in that: The method comprises: The combustion flue gas is filtered, and the filtered combustion flue gas is sequentially passed through a compressor and an air inlet valve into an adsorption tower, and then passed through an air outlet valve and a vacuum pump into a carbon isotope collection tank; During adsorption, obtaining the real-time temperature and real-time pressure of the adsorption tower, determining the preset pressure of the adsorption tower according to the real-time temperature; determining the pressure difference between the preset pressure and the real-time pressure, and determining the compression power adjustment amount of the compressor according to the pressure difference; During desorption, obtaining a first real-time carbon dioxide concentration of the adsorption tower, determining whether to start desorption based on the first real-time carbon dioxide concentration, and if desorption starts, obtaining a second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank, and setting the operating power of the vacuum pump based on the second real-time carbon dioxide concentration to achieve carbon isotope enrichment; Determining a preset pressure of the adsorption tower according to the real-time temperature includes: Presetting a first preset temperature, a second preset temperature, and a third preset temperature, wherein the first preset temperature, the second preset temperature, and the third preset temperature increase in sequence; Setting a preset pressure P of the adsorption tower according to a relationship between the real-time temperature and the first preset temperature, the second preset temperature, and the third preset temperature; If the real-time temperature is lower than the first preset temperature, the preset pressure P of the adsorption tower is set to the first preset pressure P1, that is, P=P1; If the real-time temperature is greater than or equal to the first preset temperature and the real-time temperature is less than the second preset temperature, the preset pressure P of the adsorption tower is set to the second preset pressure P2, that is, P=P2; If the real-time temperature is greater than or equal to the second preset temperature and is less than the third preset temperature, the preset pressure P of the adsorption tower is set to the third preset pressure P3, that is, P=P3; If the real-time temperature is greater than or equal to the third preset temperature, the preset pressure P of the adsorption tower is set to a fourth preset pressure P4, that is, P=P4; wherein P1>P2>P3>P4.

2. The method for enriching biogenic carbon isotopes in combustion flue gas according to claim 1, characterized in that: During adsorption, the air inlet valve is opened to pass the filtered combustion flue gas into the adsorption tower, and the compressor is turned on to compress the combustion flue gas in the adsorption tower, while the air outlet valve and the vacuum pump are closed.

3. The method for enriching biogenic carbon isotopes in combustion flue gas according to claim 1, characterized in that: During desorption, the air inlet valve and the compressor are closed, the air outlet valve is opened, and the vacuum pump is turned on to evacuate the adsorption tower.

4. The method for enriching biogenic carbon isotopes in combustion flue gas according to claim 1, characterized in that: Determining a pressure difference between the preset pressure and the real-time pressure, and determining a compression power adjustment amount of the compressor according to the pressure difference, comprising: Set the real-time pressure to P0, and determine the pressure difference Pc between the preset pressure P and the real-time pressure P0, Pc=P-P0; Presetting a first pressure difference value, a second pressure difference value, and a third pressure difference value, wherein the first pressure difference value, the second pressure difference value, and the third pressure difference value increase in sequence; setting a compression power adjustment amount A of the compressor according to a relationship between the pressure difference value Pc and the first pressure difference value, the second pressure difference value, and the third pressure difference value; If the pressure difference Pc is less than the first pressure difference, the compression power adjustment amount A of the compressor is set to the first compression power adjustment amount A1, that is, A=A1; If the pressure difference Pc is greater than or equal to the first pressure difference, and the pressure difference Pc is less than the second pressure difference, the compression power adjustment amount A of the compressor is set to the second compression power adjustment amount A2, that is, A=A2; If the pressure difference Pc is greater than or equal to the second pressure difference, and the pressure difference Pc is less than the third pressure difference, the compression power adjustment amount A of the compressor is set to the third compression power adjustment amount A3, that is, A=A3; If the pressure difference Pc is greater than or equal to the third pressure difference, the compression power adjustment amount A of the compressor is set to the fourth compression power adjustment amount A4, that is, A=A4; wherein A1<A2<A3<A4.

5. The method for enriching biogenic carbon isotopes in combustion flue gas according to claim 1, characterized in that: Determining whether to start desorption according to the first real-time carbon dioxide concentration includes: Determine a concentration difference Cc between the first real-time carbon dioxide concentration at time t and the first real-time carbon dioxide concentration at time t-1, that is, Cc=Ct-Ct-1; When the concentration difference Cc is equal to 0, it is determined that desorption begins.

6. The method for enriching biogenic carbon isotopes in combustion flue gas according to claim 1, characterized in that: Setting the operating power of the vacuum pump according to the second real-time carbon dioxide concentration includes: Pre-set CO2 concentration thresholds; determining a carbon dioxide concentration difference between the carbon dioxide concentration threshold and the second real-time carbon dioxide concentration, and setting an operating power of the vacuum pump according to the carbon dioxide concentration difference; presetting a first carbon dioxide concentration difference value, a second carbon dioxide concentration difference value, and a third carbon dioxide concentration difference value, wherein the first carbon dioxide concentration difference value, the second carbon dioxide concentration difference value, and the third carbon dioxide concentration difference value increase in sequence; setting a working efficiency W of the vacuum pump according to a relationship between the carbon dioxide concentration difference and the first carbon dioxide concentration difference, the second carbon dioxide concentration difference, and the third carbon dioxide concentration difference; If the carbon dioxide concentration difference is less than the first carbon dioxide concentration difference, the working efficiency W of the vacuum pump is set to the first preset working efficiency W1, that is, W=W1; If the carbon dioxide concentration difference is greater than or equal to the first carbon dioxide concentration difference, and the carbon dioxide concentration is less than the second carbon dioxide concentration, the working efficiency W of the vacuum pump is set to a second preset working efficiency W2, that is, W=W2; If the carbon dioxide concentration difference is greater than or equal to the second carbon dioxide concentration difference, and the carbon dioxide concentration is less than the third carbon dioxide concentration, the working efficiency W of the vacuum pump is set to a third preset working efficiency W3, that is, W=W3; If the carbon dioxide concentration difference is greater than or equal to the third carbon dioxide concentration difference, the working efficiency W of the vacuum pump is set to a fourth preset working efficiency W4, that is, W=W4; wherein W1<W2<W3<W4.

7. The method for enriching biogenic carbon isotopes in combustion flue gas according to claim 1, characterized in that: The adsorption tower is connected to a second air outlet valve. After adsorption is completed and before desorption begins, the air inlet valve is closed and the second air outlet valve is opened to release the combustion flue gas after adsorption in the adsorption tower.

8. A system for enriching biogenic carbon isotopes in combustion flue gas, for applying the method for enriching biogenic carbon isotopes in combustion flue gas according to any one of claims 1 to 7, characterized in that: The system comprises: an acquisition module, the acquisition module being used to acquire the real-time temperature and real-time pressure of the adsorption tower, and to acquire a first real-time carbon dioxide concentration of the adsorption tower and a second real-time carbon dioxide concentration at the inlet of the carbon isotope collection tank; an adsorption control module, the adsorption control module being configured to determine a preset pressure of the adsorption tower according to the real-time temperature; and to determine a pressure difference between the preset pressure and the real-time pressure, and to determine a compression power adjustment amount of the compressor according to the pressure difference; A desorption control module is used to determine whether to start desorption according to the first real-time carbon dioxide concentration. If desorption is started, the operating power of the vacuum pump is set according to the second real-time carbon dioxide concentration to achieve enrichment of carbon isotopes.

9. The system for enriching biogenic carbon isotopes in combustion flue gas according to claim 8, characterized in that: The adsorption control module is further used to control the air inlet valve; the desorption control module is further used to control the air outlet valve.

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