A system and method for coupling capture of co2

Abstract

The application discloses a system and method for coupling CO2 capture, which comprises a membrane separator for receiving CO2-containing flue gas and separating CO2 in the flue gas to obtain concentrated gas with increased CO2 concentration; a high gravity reactor in communication with a gas outlet of the membrane separator for receiving the concentrated gas and allowing the concentrated gas to be absorbed by a composite absorbent in the high gravity reactor to obtain rich liquid after absorbing CO2; a liquid separator in communication with the high gravity reactor for receiving the rich liquid and separating the rich liquid into an organic phase and an inorganic phase; a first gas-liquid separator in communication with the liquid separator for receiving the organic phase and separating a first CO2 product gas from the organic phase; and a regenerator in communication with the liquid separator for receiving the inorganic phase and separating a second CO2 product gas from the inorganic phase. The application adopts the membrane separation method-high gravity method coupling CO2 capture, can effectively make up for the defects of insufficient CO2 product gas concentration of the traditional membrane separation method, and has the advantages of low energy consumption and good selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas separation, in particular to a system and method for coupling CO2 capture. BACKGROUND

[0002] At present, post-combustion CO2 capture technology is the most commonly used CO2 emission reduction technology. Post-combustion CO2 capture technology refers to the use of various technical means to separate and recover CO2 in flue gas after fuel combustion. According to different separation methods, post-combustion CO2 capture technology can be divided into: chemical absorption method, solid adsorption method, membrane separation method and temperature-based phase separation method, etc. The chemical absorption method is a technology that uses the chemical reaction between CO2 and a chemical absorbent to selectively separate CO2 gas from flue gas. This technology is a continuous and cyclic process, including two steps of CO2 absorption and desorption. In this process, the absorbent selectively absorbs CO2 in the flue gas at a lower temperature in the absorption tower to form a CO2-rich liquid. Then the CO2-rich liquid releases the absorbed CO2 at a higher temperature in the desorption tower to regenerate the absorbent. This process can efficiently remove CO2 from flue gas and produce high-purity CO2. The removal efficiency of CO2 in flue gas can reach 99%. However, this process still faces the huge challenges of high energy consumption and high operating cost.

[0003] CN111871159 A proposes a device and method for capturing CO2 in flue gas by coupling membrane separation with alcohol amine solution. The CO2 capture method mentioned in this method is a coupling technology of membrane separation method and traditional chemical absorption method. CO2-containing flue gas passes through a membrane separator and an absorption tower in turn to complete CO2 capture. However, this method uses alcohol amine solution and absorption tower, and the energy consumption of alcohol amine absorbent regeneration is high. The alcohol amine absorbent is corrosive to equipment, the mass transfer performance of the absorption tower reaction device is poor, the CO2 capture effect is general, and the device volume and land area are large, and the investment is large. SUMMARY

[0004] Therefore, the main purpose of the present application is to provide a system and method for coupling CO2 capture. The system uses membrane separation method-coupled supergravity method to capture CO2, which can effectively compensate for the lack of CO2 product gas concentration in traditional membrane separation method, and has the advantages of low energy consumption and good selectivity.

[0005] To achieve the above-mentioned purposes, the first aspect of the present application provides a system for coupling CO2 capture, comprising:

[0006] a membrane separator for receiving CO2-containing flue gas and separating CO2 in the flue gas to obtain concentrated gas with increased CO2 concentration;

[0007] a high gravity reactor, in communication with the gas outlet of the membrane separator, for receiving the concentrated gas and allowing the concentrated gas to be absorbed by a composite absorbent comprising organic and inorganic materials in the high gravity reactor, to obtain a rich liquid after absorbing CO2;

[0008] a liquid separator, in communication with the high gravity reactor, for receiving the rich liquid and separating the rich liquid into an organic phase and an inorganic phase;

[0009] a first gas-liquid separator, in communication with the liquid separator, for receiving the organic phase and separating the organic phase to obtain a first CO2 product gas;

[0010] a regenerator, in communication with the liquid separator, for receiving the inorganic phase and separating the inorganic phase to obtain a second CO2 product gas.

[0011] Further, the system further comprises an organic phase storage tank for receiving the remaining organic phase after the first CO2 product gas is separated.

[0012] Further, the system further comprises an inorganic phase storage tank for receiving the remaining inorganic phase after the second CO2 product gas is separated.

[0013] Further, the system further comprises a first cooler, and the remaining inorganic phase enters the inorganic phase storage tank after being cooled by the first cooler.

[0014] Further, the inorganic phase in the inorganic phase storage tank and the organic phase in the organic phase storage tank return to the inside of the high gravity reactor.

[0015] Further, the system further comprises a reboiler connected to the bottom of the regenerator, and a second cooler for cooling the second CO2 product gas, a second gas-liquid separator for separating the second CO2 product gas, connected to the top of the regenerator.

[0016] The second aspect of the present application provides a method for capturing CO2, comprising:

[0017] CO2-containing flue gas enters a membrane separator to obtain a concentrated gas with increased CO2 concentration;

[0018] The concentrated gas enters the inside of a high gravity reactor and is absorbed by a composite absorbent comprising organic and inorganic materials in the high gravity reactor, to obtain a rich liquid after absorbing CO2;

[0019] The rich liquid enters a liquid separator and is separated into an organic phase and an inorganic phase;

[0020] The organic phase enters a first gas-liquid separator and is separated to obtain a first CO2 product gas;

[0021] The inorganic phase enters a regenerator to obtain a second CO2 product gas.

[0022] Further, the method further comprises: separating the remaining organic phase of the first CO2 product gas into an organic phase storage tank; and / or separating the remaining inorganic phase of the second CO2 product gas into an inorganic phase storage tank.

[0023] Further, the remaining inorganic phase enters the inorganic phase storage tank after being cooled by a first cooler.

[0024] Further, the inorganic phase in the inorganic phase storage tank and the organic phase in the organic phase storage tank return into the high gravity reactor.

[0025] Further, the method further comprises: cooling the second CO2 product gas by a second cooler, and separating the cooled second CO2 product gas by a second gas-liquid separator to obtain a pure CO2 product gas.

[0026] Further, the composite absorbent adopts a composite solution containing an organic substance and an inorganic substance, wherein the organic substance is selected from one or more of n-octanol, n-hexanol and cyclohexanone, and the inorganic substance is selected from K2CO3 aqueous solution or K2CO3 / KHCO3 mixed aqueous solution.

[0027] Compared with the prior art, the application has the following advantages:

[0028] In the application, the CO2-containing flue gas enters a membrane separator to obtain concentrated gas with increased CO2 concentration, i.e. primary concentration of CO2 is realized; then the concentrated gas enters a high gravity reactor to be absorbed by a composite absorbent in the high gravity reactor, to obtain rich liquid after absorbing CO2, i.e. secondary concentration of CO2 is realized; the rich liquid enters a liquid separator to be separated into an organic phase and an inorganic phase; the organic phase enters a first gas-liquid separator to be separated into a first CO2 product gas; and the inorganic phase enters a regenerator to be separated into a second CO2 product gas.

[0029] In summary, the application couples high gravity technology with the membrane separation method to effectively compensate for the defect of insufficient concentration of CO2 product gas in the traditional membrane separation method, to improve the concentration of CO2 product gas and significantly improve the CO2 capture effect, with the advantages of low energy consumption and good selectivity. Meanwhile, the use of the high gravity reactor and the composite absorbent can effectively improve the mass transfer performance of the CO2 absorption process, and has good capture performance at low CO2 volume fraction, which is a new high-efficiency carbon hybrid capture technology.

[0030] Other features and advantages of the application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1A system structure schematic diagram for coupling capturing CO2 is provided for an embodiment of the present application.

[0032] The reference signs are as follows: 1-CO2 gas cylinder, 2-N2 gas cylinder, 3-gas buffer tank, 4-gas flow meter, 5-membrane separator, 6-ultra-gravity reactor, 7-liquid separator, 8-first gas-liquid separator, 9-organic phase storage tank, 10-regenerator, 11-reboiler, 12, 14-coolers, 13-second gas-liquid separator, 15-inorganic phase storage tank, 16-boosting pump. DETAILED DESCRIPTION

[0033] The concept and the technical effects generated by the present application will be described below in conjunction with the embodiments, so as to fully understand the purposes, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0034] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0035] Unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" should be understood broadly, for example, it can be fixed connection, but also can be detachable connection; can be mechanical connection, but also can be electrical connection; can be directly connected, but also through the intermediate medium indirectly connected, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] Unless otherwise specified, the experimental methods in the embodiments are generally carried out according to the conventional conditions and the conditions described in the manual, or according to the conditions suggested by the manufacturer. The general equipment, materials, reagents, etc. used are commercially available, unless otherwise specified.

[0037] Reference Figure 1 The present application provides a system for coupling capturing CO2 in the first aspect, comprising:

[0038] a membrane separator 5 for receiving the CO2-containing flue gas and selectively separating CO2 in the flue gas to obtain a concentrated gas with increased CO2 concentration;

[0039] a high gravity reactor 6 in communication with the gas outlet of the membrane separator for receiving the concentrated gas and allowing the concentrated gas to be absorbed by a composite absorbent containing organic and inorganic substances in the high gravity reactor to obtain a rich liquid after absorbing CO2;

[0040] a liquid separator 7 in communication with the high gravity reactor for receiving the rich liquid and separating the rich liquid into an organic phase and an inorganic phase;

[0041] a first gas-liquid separator 8 in communication with the liquid separator for receiving the organic phase and separating a first CO2 product gas from the organic phase;

[0042] a regenerator 10 in communication with the liquid separator for receiving the inorganic phase and separating a second CO2 product gas from the inorganic phase.

[0043] In the present application, the membrane separation method is to purify and separate CO2 according to the different permeabilities of various gases through a specific membrane, and the driving force of the membrane method is the pressure / concentration difference. The greater the pressure difference, the better the membrane separation effect.

[0044] In the present application, the CO2-containing flue gas can be mixed before entering the membrane separator 5. In some examples, the CO2 and N2 generated by the CO2 cylinder 1 and the N2 cylinder 2 can be mixed uniformly in the gas buffer tank 3 before entering the membrane separator 5. Preferably, a gas flow meter 4 is arranged on the mixed gas pipeline before entering the membrane separator 5 to control the gas flow entering the membrane separator.

[0045] In the present application, the CO2 in the flue gas diffuses to the other side of the membrane through the membrane holes in the membrane separator 5. The membrane separator used can be a hollow fiber membrane reactor, a flat plate membrane reactor or a spiral membrane reactor, and the membrane material can be one or more of polyethylene, polypropylene, polytetrafluoroethylene and polyvinylidene fluoride.

[0046] In the present application, the high gravity reactor 6 can be a rotating packed bed, a fixed rotor reactor, a baffling reactor or a spiral rotor reactor. In the high gravity reactor, the centrifugal force generated by the high-speed rotation of the internal rotor cuts the liquid phase into extremely small liquid droplets, liquid filaments or liquid membranes with large specific surface area, greatly strengthening the mass transfer effect between phases and substances and greatly improving the conversion rate of the reaction. In addition, the high gravity reactor has a significantly reduced equipment size compared to the traditional packed tower, short material residence time, simple start-up and shutdown operation, and convenient equipment maintenance.

[0047] In the present application, as an example, the liquid separator 7 can be a mixed clarifier to separate the organic phase solution and the inorganic phase solution.

[0048] In the present application, as an example, the first gas-liquid separator 8 can be a cyclone separator.

[0049] Preferably, the system further comprises an organic phase tank 9 for receiving the remaining organic phase separated from the first CO2 product gas.

[0050] Preferably, the system further comprises an inorganic phase tank 15 for receiving the remaining inorganic phase separated from the second CO2 product gas.

[0051] Preferably, the system further comprises a first cooler 14, and the remaining inorganic phase enters the inorganic phase tank 15 after being cooled by the first cooler 14.

[0052] Preferably, the inorganic phase in the inorganic phase tank 15 and the organic phase in the organic phase tank 9 are returned to the hypergravity reactor for recycling to capture CO2 in the concentrated gas, and a booster pump 16 can be provided on the return pipeline as needed.

[0053] In the present application, the bottom of the regenerator is connected to a reboiler 11 for providing a heat source for the regenerator (the reboiler can be considered as a part of the regenerator), and the top of the regenerator is connected to a second cooler 12 for cooling the second CO2 product gas, a second gas-liquid separator 13 for separating the second CO2 product gas, and the obtained second CO2 product gas is stored, and the remaining flue gas can be directly discharged.

[0054] In the present application, as an example, the second gas-liquid separator 13 can be a cyclone separator.

[0055] Reference Figure 1The CO2 capturing process of the present application is as follows: CO2 from a CO2 cylinder 1 and N2 from a N2 cylinder 2 are mixed uniformly in a gas buffer tank 3, and then enter a membrane separator 5 after passing through a gas flow meter 4. CO2 in flue gas diffuses through membrane holes to the other side of the membrane, and the obtained concentrated gas leaves the membrane separator 5 and enters a high gravity reactor 6. Inorganic solution in an inorganic phase storage tank 15 and organic solution in an organic phase storage tank 9 enter the high gravity reactor 6 through a booster pump 16. Inside the high gravity reactor 6, CO2 in the concentrated gas is absorbed by a composite absorbent containing organic matter and inorganic matter, and the decarburization treatment of the flue gas is completed. The rich liquid after absorbing CO2 enters a liquid separator 7, and the organic phase and the inorganic phase are separated. The organic phase solution enters an organic phase storage tank 13 after the first CO2 product gas is separated through a first gas-liquid separator 8. The inorganic phase solution enters a regenerator 10 after the second CO2 product gas is separated, and then enters an inorganic phase storage tank 15 through a first cooler 14. The second CO2 product gas goes to a storage tank (not shown in the figure) after passing through a second cooler 12 and a second gas-liquid separator 13. The remaining flue gas after treatment is directly exhausted.

[0056] The second aspect of the present application provides a method for coupling CO2 capture, comprising:

[0057] CO2-containing flue gas enters a membrane separator for gas separation, and a concentrated gas with increased CO2 concentration is obtained;

[0058] The concentrated gas enters a high gravity reactor and is absorbed by a composite absorbent containing organic matter and inorganic matter inside the high gravity reactor, and a rich liquid after absorbing CO2 is obtained;

[0059] The rich liquid enters a liquid separator and is separated into an organic phase and an inorganic phase;

[0060] The organic phase enters a first gas-liquid separator and is separated into a first CO2 product gas;

[0061] The inorganic phase enters a regenerator and is separated into a second CO2 product gas.

[0062] Preferably, the method further comprises: the remaining organic phase after separation of the first CO2 product gas enters an organic phase storage tank; and / or, the remaining inorganic phase after separation of the second CO2 product gas enters an inorganic phase storage tank.

[0063] Preferably, the remaining inorganic phase enters an inorganic phase storage tank after being cooled by a first cooler.

[0064] Preferably, the inorganic phase in the inorganic phase storage tank and the organic phase in the organic phase storage tank return to the inside of the high gravity reactor.

[0065] Preferably, the method further comprises: the second CO2 product gas enters a second cooler for cooling, and then enters a second gas-liquid separator for separation to obtain a pure CO2 product gas.

[0066] Preferably, the composite absorbent adopts a composite solution containing an organic substance and an inorganic substance, wherein the organic substance is selected from one or more of n-octanol, n-hexanol and cyclohexanone, and the inorganic substance is selected from an aqueous K2CO3 solution or a mixed aqueous K2CO3 / KHCO3 solution.

[0067] As a more preferred solution, when the organic phase is n-octanol, the volume fraction of n-octanol is 0.1-10%; when the organic phase is n-hexanol or cyclohexanone, the volume fraction of n-hexanol or cyclohexanone in the composite absorbent is 0.1-20%.

[0068] Further preferably, when the organic phase is n-octanol, the volume fraction of n-octanol is 1-5%; when the organic phase is n-hexanol or cyclohexanone, the volume fraction of n-hexanol or cyclohexanone in the composite absorbent is 2-10%.

[0069] In the present application, the setting of the concentration of the organic phase is mainly based on the physical properties such as viscosity and volatility of the organic phase, and within the above setting range, the CO2 capture effect is better.

[0070] As a more preferred solution, when the aqueous phase is a K2CO3 solution, the concentration of the K2CO3 solution is 0.01-2 mol / L; when the aqueous phase is a K2CO3 / KHCO3 solution, the concentration of the K2CO3 / KHCO3 solution is 0.01-1 mol / L.

[0071] Further preferably, when the aqueous phase is a K2CO3 solution, the concentration of the K2CO3 solution is 0.1-1 mol / L; when the aqueous phase is a K2CO3 / KHCO3 solution, the concentration of the K2CO3 / KHCO3 solution is 0.1-0.5 mol / L.

[0072] In the present application, the setting of the above concentration of the inorganic phase is mainly based on factors such as solubility of the inorganic phase.

[0073] As a more preferred solution, the rotation speed of the high gravity reactor is 200-2500 rpm, and within the above setting range, the CO2 absorption effect is good, and the gain effect is not obvious beyond the range.

[0074] Further preferably, the rotation speed of the high gravity reactor is 400-1800 rpm.

[0075] As a more preferred solution, the temperature of the composite absorbent input into the high gravity reactor is 20-70℃, and the temperature is a range in which the CO2 absorption effect is better.

[0076] Further preferably, the temperature of the composite absorbent inputted into the high gravity reactor is 30-60°C.

[0077] As one of the more preferred solutions, the volume ratio of the gas-liquid flow inputted into the high gravity reactor is 1-500:1, i.e. the volume ratio of the concentrated gas to the composite absorbent, which is a more practical operating range.

[0078] Further preferably, the volume ratio of the gas-liquid flow inputted into the high gravity reactor is 1-100:1.

[0079] In the present application, the cooperation between the rotation speed of the high gravity reactor, the temperature of the composite absorbent inputted into the high gravity reactor and the volume ratio of the gas-liquid can achieve a better CO2 absorption effect.

[0080] As one of the more preferred solutions, the temperature of the inorganic phase inputted into the regenerator is 80-140°C, which is a suitable temperature for regeneration.

[0081] Further preferably, the temperature of the inorganic phase inputted into the regenerator is 100-120°C.

[0082] The following examples are used to illustrate the system and method for coupling and capturing CO2 of the present application.

[0083] Example 1

[0084] The CO2-containing flue gas (CO2 concentration is 14%) is absorbed by the membrane separation-high gravity coupling process, the flue gas and the K2CO3+ n-octanol mixed solution are respectively sent into the membrane separator and the high gravity reactor according to the volume ratio of the gas-liquid flow of 100:1, the liquid temperature of the K2CO3+ n-octanol mixed solution is 40°C, the temperature and pressure of the CO2-containing flue gas are 40°C and 0.1 MPa respectively, the concentration of the K2CO3 solution is 0.1 mol / L, the volume fraction of n-octanol is 5%, the rotation speed of the rotor of the high gravity reactor is 800 revolutions / minute, the desorption temperature of the regenerator is 110°C, the membrane separator is a polypropylene fiber membrane reactor, and the high gravity reactor is a rotating packed bed. After the simulated flue gas is treated by the coupling process, the CO2 capture rate is 80%, and the CO2 concentration of the product gas is 99%.

[0085] Example 2

[0086] The membrane separation-ultra-gravity coupling process was used to absorb the simulated flue gas containing CO2 (CO2 concentration of 10%), the flue gas and K2CO3+ n-octanol mixed solution were respectively sent into the membrane separator and the ultra-gravity reactor according to the gas-liquid flow volume ratio of 40:1, the liquid temperature of the K2CO3+ n-octanol mixed solution was 60 ℃, the temperature and pressure of the flue gas containing CO2 were 40 ℃ and 0.1 MPa respectively, the K2CO3 solution concentration was 0.1 mol / L, the volume fraction of n-octanol was 5%, the rotor speed of the ultra-gravity reactor was 800 revolutions / minute, the desorption temperature of the regenerator was 120 ℃, the membrane separator was a polypropylene middle fiber membrane reactor, and the ultra-gravity reactor was a rotating packed bed. After the simulated flue gas was treated by the coupling process, the CO2 capture rate was 89%, and the CO2 concentration of the product gas was 99%.

[0087] Example 3

[0088] The membrane separation-ultra-gravity coupling process was used to absorb the simulated flue gas containing CO2 (CO2 concentration of 15%), the flue gas and K2CO3+ n-octanol mixed solution were respectively sent into the membrane separator and the ultra-gravity reactor according to the gas-liquid flow volume ratio of 25:1, the liquid temperature of the K2CO3+ n-octanol mixed solution was 70 ℃, the temperature and pressure of the flue gas containing CO2 were 40 ℃ and 0.1 MPa respectively, the K2CO3 solution concentration was 0.15 mol / L, the volume fraction of n-octanol was 5%, the rotor speed of the ultra-gravity reactor was 1400 revolutions / minute, the desorption temperature of the regenerator was 120 ℃, the membrane separator was a polypropylene middle fiber membrane reactor, and the ultra-gravity reactor was a rotating packed bed. After the simulated flue gas was treated by the coupling process, the CO2 capture rate was 93%, and the CO2 concentration of the product gas was 99%.

[0089] Example 4

[0090] The membrane separation-ultra-gravity coupling process was used to absorb the simulated flue gas containing CO2 (CO2 concentration of 15%), the flue gas and K2CO3 / KHCO3+ n-hexanol mixed solution were respectively sent into the membrane separator and the ultra-gravity reactor according to the gas-liquid flow volume ratio of 50:1, the liquid temperature of the K2CO3 / KHCO3+ n-hexanol mixed solution was 60 ℃, the temperature and pressure of the flue gas containing CO2 were 40 ℃ and 0.1 MPa respectively, the K2CO3 solution concentration was 0.1 mol / L, the volume fraction of n-hexanol was 6%, the rotor speed of the ultra-gravity reactor was 1000 revolutions / minute, the desorption temperature of the regenerator was 120 ℃, the membrane separator was a polypropylene middle fiber membrane reactor, and the ultra-gravity reactor was a rotating packed bed. After the simulated flue gas was treated by the coupling process, the CO2 capture rate was 86%, and the CO2 concentration of the product gas was 99%.

[0091] Example 5

[0092] The absorption of CO2-containing flue gas (CO2 concentration of 12%) uses a membrane separation method-coupling process of high gravity method. The flue gas and K2CO3 / KHCO3+ cyclohexanone mixed solution are respectively sent into the membrane separator and the high gravity reactor according to the gas-liquid flow volume ratio of 50:1. The liquid temperature of the K2CO3 / KHCO3+ cyclohexanone mixed solution is 40°C. The temperature and pressure of the CO2-containing flue gas are 40°C and 0.1 MPa respectively. The K2CO3 solution concentration is 0.1 mol / L. The volume fraction of cyclohexanone is 10%. The rotor speed of the high gravity reactor is 800 revolutions / minute. The desorption temperature of the regenerator is 120°C. The membrane separator is a polypropylene fiber membrane reactor. The high gravity reactor is a fixed rotor reactor. After the simulated flue gas is treated by the coupling process, the CO2 capture rate is 84% and the CO2 concentration of the product gas is 99%.

[0093] Example 6

[0094] The absorption of CO2-containing flue gas (CO2 concentration of 15%) uses a membrane separation method-coupling process of high gravity method. The flue gas and K2CO3 / KHCO3+ n-octanol mixed solution are respectively sent into the membrane separator and the high gravity reactor according to the gas-liquid flow volume ratio of 80:1. The liquid temperature of the K2CO3 / KHCO3+ n-octanol mixed solution is 40°C. The temperature and pressure of the CO2-containing flue gas are 40°C and 0.1 MPa respectively. The K2CO3 solution concentration is 0.1 mol / L. The volume fraction of n-octanol is 3%. The rotor speed of the high gravity reactor is 1000 revolutions / minute. The desorption temperature of the regenerator is 120°C. The membrane separator is a polypropylene fiber membrane reactor. The high gravity reactor is a baffling reactor. After the simulated flue gas is treated by the coupling process, the CO2 capture rate is 85% and the CO2 concentration of the product gas is 99%.

[0095] Comparative Example 1

[0096] The absorption of CO2-containing flue gas (CO2 concentration of 15%) uses a membrane separation method. The flue gas is sent into the membrane separator. The temperature and pressure of the CO2-containing simulated flue gas are 40°C and 0.1 MPa respectively. The membrane separator is a polyethylene fiber membrane reactor. After the simulated flue gas is treated, the CO2 capture rate is 55% and the product gas concentration is 50%.

[0097] Comparative Example 2

[0098] Different from example 1 in that: using 0.1 mol / L K2CO3 solution as absorbent, absorbing CO2-containing flue gas (CO2 concentration is 14%), using membrane separation method-high gravity method coupling process, gas-liquid flow volume ratio is 100:1, K2CO3 liquid temperature is 40℃, the rotor speed of high gravity reactor is 800 rpm, the desorption temperature of regenerator is 110℃, the membrane separator is polypropylene fiber membrane reactor, and the high gravity reactor is rotating packed bed. After the simulation flue gas is treated by the coupling process, the CO2 capture rate is 65%, and the CO2 concentration of product gas is 99%.

[0099] From the above examples, it can be seen that the method provided by the application can meet the capture requirement of CO2-containing gas, CO2 is captured by using membrane separation method-high gravity method coupling process, and the capture rate can be up to 90% or more, which is a novel and effective method for capturing CO2. By using the method, the CO2 product gas concentration in the CO2 capture process can be significantly improved, the CO2 capture efficiency is strengthened, and the regeneration energy consumption is reduced; the process of the application is simple, continuous operation, and high efficiency. Example 3 has the best effect in examples 1-6, and the CO2 absorption effect is improved by reducing the gas-liquid volume ratio, increasing the rotor speed of the high gravity reactor and increasing the CO2 absorption temperature. The CO2 capture rate of comparative example 1 using only the membrane separation method and comparative example 2 using only the conventional single absorbent is lower than that of examples.

[0100] Obviously, the above examples of the application are only examples for clearly illustrating the application, and are not intended to limit the implementation modes of the application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. It is impossible to enumerate all the implementation modes here. Any obvious changes or variations derived from the technical solutions of the application are within the scope of the spirit of the application.

Claims

1. A system for coupling CO2 capture, characterized by, The system comprises: a membrane separator for receiving a CO2-containing flue gas and separating CO2 in the flue gas to obtain a concentrated gas with increased CO2 concentration; a high gravity reactor in communication with a gas outlet of the membrane separator for receiving the concentrated gas and allowing the concentrated gas to be absorbed by a composite absorbent containing organic and inorganic substances in the high gravity reactor to obtain a rich liquid after absorbing CO2; a liquid separator in communication with the high gravity reactor for receiving the rich liquid and separating the rich liquid into an organic phase and an inorganic phase; a first gas-liquid separator in communication with the liquid separator for receiving the organic phase and separating the organic phase to obtain a first CO2 product gas; a regenerator in communication with the liquid separator for receiving the inorganic phase and separating the inorganic phase to obtain a second CO2 product gas.

2. The system for capturing CO2 by coupling according to claim 1, characterized in that, The system further comprises an organic phase storage tank for receiving the remaining organic phase after the first CO2 product gas is separated; and / or, The system further comprises an inorganic phase storage tank for receiving the remaining inorganic phase after the second CO2 product gas is separated.

3. The system for capturing CO2 by coupling according to claim 2, wherein, The system further comprises a first cooler, and the remaining inorganic phase enters the inorganic phase storage tank after being cooled by the first cooler.

4. The system for capturing CO2 by coupling according to claim 2, wherein, The inorganic phase in the inorganic phase storage tank and the organic phase in the organic phase storage tank return to the inside of the high gravity reactor.

5. The system for capturing CO2 by coupling according to any one of claims 1 to 4, characterized in that, The system further comprises a reboiler connected to the bottom of the regenerator, and a second cooler for cooling the second CO2 product gas, a second gas-liquid separator for separating the second CO2 product gas connected to the top of the regenerator.

6. A method of coupling CO2 capture, characterized by, The method comprises: a CO2-containing flue gas enters a membrane separator to obtain a concentrated gas with increased CO2 concentration; the concentrated gas enters a high gravity reactor and is absorbed by a composite absorbent containing organic and inorganic substances in the high gravity reactor to obtain a rich liquid after absorbing CO2; the rich liquid enters a liquid separator and is separated into an organic phase and an inorganic phase; the organic phase enters a first gas-liquid separator and is separated to obtain a first CO2 product gas; the inorganic phase enters a regenerator and is separated to obtain a second CO2 product gas.

7. The method of claim 6, wherein the CO2 is captured by coupling. The method further comprises:

8. The method of claim 7, wherein the CO2 is captured by coupling. the remaining organic phase after the first CO2 product gas is separated enters an organic phase storage tank; and / or, 9. The method of claim 7, wherein the CO2 is captured by coupling. the remaining inorganic phase after the second CO2 product gas is separated enters an inorganic phase storage tank.

10. The method of claim 6-9, wherein the CO2 is captured by coupling, and The remaining inorganic phase enters an inorganic phase storage tank after being cooled by a first cooler.

11. The method of claim 6, wherein the CO2 is captured by coupling. The inorganic phase in the inorganic phase storage tank and the organic phase in the organic phase storage tank return to the inside of the high gravity reactor. The method further comprises: the second CO2 product gas enters a second cooler for cooling, and enters a second gas-liquid separator for separation to obtain a pure CO2 product gas. The composite absorbent is a composite solution containing organic and inorganic substances, wherein the organic substance is selected from one or more of n-octanol, n-hexanol, and cyclohexanone, and the inorganic substance is selected from an aqueous K2CO3 solution or a mixed aqueous K2CO3 / KHCO3 solution.

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