Air separation system with CO2 capture

Abstract

The present invention provides an air separation system with a carbon dioxide capture function, the air separation system comprising a molecular sieve purifier, a first separation device, an alkali liquid capture device, an electrolyzer and a second separation device, the molecular sieve purifier is used to adsorb carbon dioxide in the air, the first separation device is used to obtain air discharged from the molecular sieve purifier, separate and generate oxygen and nitrogen, the alkali liquid capture device is arranged upstream of the molecular sieve purifier to capture carbon dioxide in the air, and / or, is connected to the molecular sieve purifier through a first air supply pipeline to obtain carbon dioxide desorbed and discharged by the molecular sieve purifier, the electrolyzer is used to obtain liquid discharged from the alkali liquid capture device and perform electrolysis, and the second separation device is used to obtain the mixed gas discharged from the anode of the electrolyzer and separate to produce oxygen. The air separation system of the present invention captures carbon dioxide through the alkali liquid capture device, and captures carbon dioxide and obtains oxygen and hydrogen through the electrolyzer and the second separation device.

Description

Technical Field

[0001] The invention relates to the technical field of air separation equipment, and in particular to an air separation system with a carbon dioxide capture function. Background Art

[0002] An air separation unit is an industrial equipment device used to separate the various gas components in the air and produce oxygen, nitrogen, argon and other gases of the air components. In the related art, a molecular sieve purifier is set to remove impurities such as carbon dioxide in the air to purify the air, and a turbine expander and a distillation tower are set to separate the purified air to obtain nitrogen and oxygen. However, in the related art, carbon dioxide is only used as an impurity to be adsorbed by the molecular sieve purifier, and is not further captured or fully utilized. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides an air separation system with a carbon dioxide capture function, which captures carbon dioxide through an alkaline liquid capture device, and captures carbon dioxide through an electrolyzer and a second separation device to obtain oxygen and hydrogen.

[0004] The air separation system with carbon dioxide capture function according to the embodiment of the present invention comprises:

[0005] A molecular sieve purifier, wherein the molecular sieve purifier is used to receive air and adsorb carbon dioxide in the air;

[0006] a first separation device, the first separation device being in communication with the molecular sieve purifier and used for separating the air exhausted from the molecular sieve purifier and generating oxygen and nitrogen;

[0007] an alkali liquid capture device, the alkali liquid capture device being arranged upstream of the molecular sieve purifier to capture carbon dioxide in the air and discharge the captured air to the molecular sieve purifier, and / or the alkali liquid capture device being connected to the molecular sieve purifier through a first air supply pipeline to obtain carbon dioxide discharged by desorption from the molecular sieve purifier;

[0008] An electrolytic cell, the electrolytic cell having a liquid inlet, an anode mixed gas outlet and a cathode hydrogen outlet, the liquid inlet of the electrolytic cell being in communication with the alkali liquid capture device so that the electrolytic cell can obtain the liquid discharged by the alkali liquid capture device and perform electrolysis;

[0009] The second separation device is connected to the anode mixed gas outlet of the electrolytic cell to obtain the mixed gas discharged from the anode mixed gas outlet and separate it into oxygen and carbon dioxide.

[0010] The air separation system with carbon dioxide capture function of the embodiment of the present invention captures carbon dioxide in the air through an alkali liquid capture device to reduce the workload of the molecular sieve purifier, and / or captures and obtains carbon dioxide desorbed and discharged by the molecular sieve purifier through the alkali liquid capture device, and then obtains the liquid discharged by the alkali liquid capture device through an electrolytic cell and electrolyzes it, and obtains the mixed gas discharged from the anode mixed gas outlet of the electrolytic cell through a second separation device and performs a separation operation, so as to utilize the alkali liquid capture device to capture carbon dioxide and obtain oxygen and hydrogen, thereby achieving carbon dioxide capture and increasing oxygen production, and also being able to obtain by-product hydrogen.

[0011] In some embodiments, the first separation device comprises:

[0012] a turbo expander, the turbo expander being in communication with the molecular sieve purifier for deep cooling the air discharged from the molecular sieve purifier;

[0013] A distillation tower is connected to the turbo expander to separate the deep-cooled air and generate oxygen and nitrogen.

[0014] In some embodiments, the second separation device is a cryogenic device, and the air separation system further includes a refrigeration pipeline, which connects the cryogenic device and the turbine expander so that the medium in the refrigeration pipeline transfers the refrigeration generated by the turbine expander to the cryogenic device.

[0015] In some embodiments, the cooling pipeline is connected to the turbine expander and the distillation tower;

[0016] The cryogenic device comprises:

[0017] a second gas supply pipeline, one end of which is in communication with the anode mixed gas outlet;

[0018] A cryogenic tower, the cryogenic tower being connected to the other end of the second gas supply pipeline so that the cryogenic tower obtains the mixed gas discharged from the anode mixed gas outlet and separates the mixed gas into oxygen and carbon dioxide;

[0019] The cryogenic device further comprises:

[0020] a heat exchanger, the heat exchanger being arranged outside the cryogenic tower and connecting the cooling pipeline and the second gas supply pipeline, so as to be used for heat exchange between the medium in the cooling pipeline and the mixed gas in the second gas supply pipeline; and / or

[0021] A condenser evaporator is arranged inside the cryogenic tower, and the condenser evaporator is connected to the cooling pipeline to exchange heat between the medium in the cooling pipeline and the mixed gas in the cryogenic tower.

[0022] In some embodiments, the distillation tower has a contaminated nitrogen gas discharge pipeline, and the contaminated nitrogen gas discharge pipeline is connected to the molecular sieve purifier, so that the molecular sieve purifier receives the contaminated nitrogen gas and desorbs and discharges carbon dioxide;

[0023] The molecular sieve purifier has a carbon dioxide discharge port, which is connected to the atmosphere, or is connected to the alkali solution capture device through the first gas supply pipeline.

[0024] In some embodiments, the molecular sieve purifier has an air inlet and a contaminated nitrogen inlet that can be opened and closed alternately, the contaminated nitrogen inlet is connected to the contaminated nitrogen exhaust pipeline, the molecular sieve purifier has an adsorption state and a desorption state, in the adsorption state, the air inlet is opened and the contaminated nitrogen inlet is closed, in the desorption state, the air inlet is closed and the contaminated nitrogen inlet is opened, the molecular sieve purifiers are at least two in parallel, at least one of the molecular sieve purifiers is in the adsorption state, and at least one of the molecular sieve purifiers is in the desorption state.

[0025] In some embodiments, the alkali liquid capture device has a liquid supply port at the top and a liquid discharge port at the bottom;

[0026] The electrolytic cell also has a liquid outlet;

[0027] The air separation system also includes:

[0028] a liquid supply pipeline, the liquid supply pipeline being connected with the liquid discharge port and the liquid inlet;

[0029] A circulation pipeline, the circulation pipeline communicating with the liquid discharge port and the liquid supply port;

[0030] A regeneration liquid pipeline is connected to the liquid outlet and the liquid supply port.

[0031] In some embodiments, the air separation system further comprises a compressor, the molecular sieve purifier is connected to the compressor and is located downstream of the compressor, and the compressor is used to compress air and supply the compressed air to the molecular sieve purifier.

[0032] In some embodiments, the alkali solution capture device is connected between the compressor and the molecular sieve purifier; or

[0033] The air separation system further comprises an air cooler, which is connected between the compressor and the molecular sieve purifier. The alkali liquid collection device is located upstream of the compressor, or the alkali liquid collection device is connected to the molecular sieve purifier through the first air supply pipeline.

[0034] In some embodiments, the air separation device further comprises an air impurity remover, the compressor is located upstream of the alkali solution capture device, the air impurity remover is communicated with the compressor, and the air impurity remover is located upstream of the compressor; or

[0035] The alkali liquid capturing device is located upstream of the compressor, the air impurity remover is communicated with the alkali liquid capturing device, and the air impurity remover is located upstream of the alkali liquid capturing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The structure of the air separation system with carbon dioxide capture function according to the embodiment of the present invention is shown in FIG. Figure 1 ;

[0037] Figure 2 The structure of the air separation system with carbon dioxide capture function according to the embodiment of the present invention is shown in FIG. Figure 2 ;

[0038] Figure 3 The structure of the air separation system with carbon dioxide capture function according to the embodiment of the present invention is shown in FIG. Figure 3 .

[0039] Reference numerals:

[0040] 1. Molecular sieve purifier; 101. Carbon dioxide outlet; 2. First separation device; 201. Turbine expander; 202. Distillation tower; 203. Dirty nitrogen outlet pipeline; 3. Alkali liquid capture device; 4. First gas supply pipeline; 5. Electrolyzer; 501. Liquid inlet; 502. Anode mixed gas outlet; 503. Cathode hydrogen outlet; 504. Liquid outlet; 6. Second separation device; 601. Second gas supply pipeline; 602. Cryogenic tower; 603. Heat exchanger; 7. Cooling pipeline; 8. Liquid supply pipeline; 9. Circulation pipeline; 10. Regeneration liquid pipeline; 11. Compressor; 12. Air cooler; 13. Air impurity remover; 14. Blower. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0042] Please refer to the following Figure 1 -Attached Figure 3 An air separation system with carbon dioxide capture function according to an embodiment of the invention is described.

[0043] like Figure 1-Figure 3As shown, the air separation system with carbon dioxide capture function according to the embodiment of the present invention includes a molecular sieve purifier 1, a first separation device 2, an alkali solution capture device 3, an electrolytic cell 5 and a second separation device 6.

[0044] The molecular sieve purifier 1 is used to receive air and adsorb carbon dioxide in the air. The first separation device 2 is connected to the molecular sieve purifier 1 to separate the air discharged from the molecular sieve purifier 1 and generate oxygen and nitrogen.

[0045] Specifically, Figure 1-Figure 3 As shown, the molecular sieve purifier 1 is connected to the first separation device 2 through a pipeline, and the molecular sieve purifier 1 is located upstream of the first separation device 2. The air first passes through the molecular sieve purifier 1 to remove carbon dioxide, water and part of hydrocarbons under the adsorption action of the molecular sieve purifier 1, and then enters the first separation device 2 for gas separation, thereby generating oxygen and nitrogen. The oxygen and nitrogen are respectively discharged from the first separation device 2 for collection and storage.

[0046] The alkali liquid capture device 3 is arranged upstream of the molecular sieve purifier 1 to capture carbon dioxide in the air and discharge the captured air to the molecular sieve purifier 1, and / or the alkali liquid capture device 3 is connected to the molecular sieve purifier 1 through the first air supply pipeline 4 to obtain the carbon dioxide desorbed and discharged by the molecular sieve purifier 1.

[0047] Specifically, in Figure 1 In the embodiment shown, the alkali liquid capture device 3 is connected to the molecular sieve purifier 1 through a pipeline, and the alkali liquid capture device 3 is located upstream of the molecular sieve purifier 1, so the air enters the molecular sieve purifier 1 after passing through the alkali liquid capture device 3. When the air is in the alkali liquid capture device 3, most of the carbon dioxide in the air is absorbed and captured by the alkali liquid in the alkali liquid capture device 3. X 、N XHarmful gases such as carbon dioxide are also absorbed by the alkali solution. The air after the capture operation is discharged from the alkali solution capture device 3 to the molecular sieve purifier 1. The molecular sieve purifier 1 adsorbs and captures the remaining carbon dioxide in the air again, and then sends the air to the first separation device 2. Therefore, the alkali solution capture device 3 plays a role in capturing most of the carbon dioxide. At the same time, since the capture operation of the alkali solution capture device 3 occurs before the molecular sieve purifier 1, the carbon dioxide content of the air entering the molecular sieve purifier 1 is greatly reduced. Therefore, the alkali solution capture device 3 also plays a role in reducing the workload of the molecular sieve purifier 1. At the same time, the alkali solution capture device 3 is also connected to the molecular sieve purifier 1 through the first air supply pipeline 4. The molecular sieve purifier 1 desorbs the adsorbed and captured carbon dioxide during regeneration, and the desorbed carbon dioxide is sent to the alkali solution capture device 3 through the first air supply pipeline 4. The alkali solution in the alkali solution capture device 3 also absorbs and captures the carbon dioxide desorbed from the molecular sieve purifier 1, so that all the carbon dioxide in the air is finally absorbed and captured by the alkali solution in the alkali solution capture device 3 for utilization.

[0048] In such Figure 2 In the embodiment shown, the alkali liquid capture device 3 is connected to the molecular sieve purifier 1 only through a pipeline, and the alkali liquid capture device 3 is located upstream of the molecular sieve purifier 1, so the air enters the molecular sieve purifier 1 after passing through the alkali liquid capture device 3. When the air is in the alkali liquid capture device 3, most of the carbon dioxide in the air is absorbed and captured by the alkali liquid in the alkali liquid capture device 3. X 、N X Harmful gases such as carbon dioxide are also absorbed by the alkali solution. The air after the capture operation is discharged from the alkali solution capture device 3 to the molecular sieve purifier 1. The molecular sieve purifier 1 adsorbs and captures the remaining carbon dioxide in the air again, and then sends the air to the first separation device 2. Therefore, the alkali solution capture device 3 plays a role in capturing most of the carbon dioxide. At the same time, since the capture operation of the alkali solution capture device 3 occurs before the molecular sieve purifier 1, the carbon dioxide content of the air entering the molecular sieve purifier 1 is greatly reduced. Therefore, the alkali solution capture device 3 also plays a role in reducing the workload of the molecular sieve purifier 1.

[0049] In such Figure 3 In the embodiment shown, the alkali liquid capture device 3 is connected to the molecular sieve purifier 1 only through the first air supply pipeline 4. The air enters the molecular sieve purifier 1 and captures carbon dioxide before entering the first separation device 2. The molecular sieve purifier 1 desorbs the adsorbed and captured carbon dioxide during regeneration, and the desorbed carbon dioxide is sent to the alkali liquid capture device 3 through the first air supply pipeline 4. The alkali liquid in the alkali liquid capture device 3 absorbs and captures the carbon dioxide desorbed from the molecular sieve purifier 1 for subsequent use. Therefore, the alkali liquid capture device 3 plays a role in obtaining the carbon dioxide desorbed by the molecular sieve purifier 1, so as to facilitate the use of the carbon dioxide.

[0050] The electrolytic cell 5 has a liquid inlet 501, an anode mixed gas outlet 502 and a cathode hydrogen outlet 503. The liquid inlet 501 of the electrolytic cell 5 is connected to the alkali liquid capture device 3 so that the electrolytic cell 5 can obtain the liquid discharged by the alkali liquid capture device 3 and perform electrolysis.

[0051] Specifically, Figure 1-Figure 3 As shown, the electrolytic cell 5 has a liquid inlet 501, an anode mixed gas outlet 502 and a cathode hydrogen outlet 503, wherein the liquid inlet 501 is arranged on the anode side of the electrolytic cell 5, and the liquid inlet 501 is connected with the alkali liquid capture device 3 through a pipeline. After absorbing and capturing carbon dioxide, the alkali liquid in the alkali liquid capture device 3 enters the electrolytic cell 5 through the liquid inlet 501 through the pipeline. Under the electrolysis operation, the liquid discharged from the alkali liquid capture device 3 generates mixed gas and hydrogen, and the mixed gas is discharged from the anode mixed gas outlet 502, and the hydrogen is discharged from the cathode hydrogen outlet 503.

[0052] The second separation device 6 is communicated with the anode mixed gas outlet 502 of the electrolytic cell 5 to obtain the mixed gas discharged from the anode mixed gas outlet 502 and separate it into oxygen and carbon dioxide.

[0053] Specifically, Figure 1-Figure 3 As shown, the second separation device 6 is connected to the anode mixed gas outlet 502 through a pipeline, and the mixed gas discharged from the anode mixed gas outlet 502 enters the second separation device 6 for separation operation to produce oxygen and carbon dioxide. Therefore, the air separation system implemented in the present invention is that the second separation device 6 and the first separation device 2 jointly produce oxygen to increase the output of oxygen.

[0054] The air separation system with carbon dioxide capture function in the embodiment of the present invention captures carbon dioxide in the air through an alkali liquid capture device to reduce the workload of the molecular sieve purifier, and / or captures and obtains carbon dioxide desorbed and discharged by the molecular sieve purifier through the alkali liquid capture device, and then obtains the liquid discharged by the alkali liquid capture device through an electrolytic cell and electrolyzes it, and obtains the mixed gas discharged from the anode mixed gas outlet of the electrolytic cell through a second separation device and performs a separation operation, so as to obtain oxygen and hydrogen using the carbon dioxide captured by the alkali liquid capture device, thereby achieving full utilization of carbon dioxide and increasing oxygen production, and at the same time being able to obtain by-product hydrogen.

[0055] In some embodiments, the first separation device 2 includes a turbine expander 201 and a distillation tower 202. The turbine expander 201 is connected to the molecular sieve purifier 1 to deep-cool the air discharged from the molecular sieve purifier 1. The distillation tower 202 is connected to the turbine expander 201 to separate the deep-cooled air and generate oxygen and nitrogen.

[0056] like Figure 1-Figure 3As shown, the first separation device 2 includes a turbine expander 201 and a distillation tower 202. The turbine expander 201 and the distillation tower 202 are connected by a pipeline. The turbine expander 201 is used to generate the cooling capacity required for gas separation. The air discharged from the molecular sieve purifier 1 is deep-cooled under the cooling effect of the turbine expander 201. Deep cooling means that the air is in the temperature range of 233K-77K. The deep-cooled air is separated in the distillation tower 202 according to the different evaporation temperatures of each component, thereby separating oxygen and nitrogen. The distillation tower 202 has at least two gas exhaust ports, one of which is used to discharge oxygen and the other is used to discharge nitrogen.

[0057] It is understandable that the first separation device is not limited to including a turbine expander and a distillation tower. In other embodiments, the first separation device may also be a cryogenic device, a catalytic oxidation device, an adsorption device or a membrane separation device.

[0058] In some embodiments, the second separation device 6 is a cryogenic device, and the air separation system further includes a cooling pipeline 7, which connects the cryogenic device and the turbine expander 201 so that the medium in the cooling pipeline 7 transfers the cooling energy generated by the turbine expander 201 to the cryogenic device.

[0059] like Figure 1-Figure 3 As shown, the second separation device 6 is a cryogenic device, and the cryogenic device and the turbine expander 201 are connected through a cold pipe 7. A medium capable of carrying and transferring cold is provided in the cold pipe 7. Part of the cold generated by the turbine expander 201 is transferred to the cryogenic device through the cold pipe 7 to condense and liquefy the mixed gas in the cryogenic device, so that the cryogenic device can separate the gas. The cold used to condense and liquefy the gas in the first separation device 2 and the second separation device 6 comes from the turbine expander 201, so that the cold of the turbine expander 201 is fully utilized.

[0060] It is understandable that the second separation device is not limited to being a cryogenic device. In other embodiments, the second separation device may also be a catalytic oxidation device, an adsorption device or a membrane separation device.

[0061] In some embodiments, the cold pipeline 7 is connected to the turbine expander 201 and the distillation tower 202. The cryogenic device includes a second gas supply pipeline 601 and a cryogenic tower 602, and one end of the second gas supply pipeline 601 is connected to the anode mixed gas outlet 502. The cryogenic tower 602 is connected to the other end of the second gas supply pipeline 601, so that the cryogenic tower 602 obtains the mixed gas discharged from the anode mixed gas outlet 502 and separates the mixed gas to produce oxygen and carbon dioxide. The cryogenic device also includes a heat exchanger 603 and / or a condenser evaporator, the heat exchanger 603 is arranged outside the cryogenic tower 602, and the heat exchanger 603 is connected to the cold pipeline 7 and the second gas supply pipeline 601, so as to exchange heat between the medium in the cold pipeline 7 and the mixed gas in the second gas supply pipeline 601, and the condenser evaporator is arranged inside the cryogenic tower 602, and the condenser evaporator is connected to the cold pipeline 7, so as to exchange heat between the medium in the cold pipeline 7 and the mixed gas in the cryogenic tower 602.

[0062] like Figure 1-Figure 3 As shown, the cooling pipeline 7 connects the turbine expander 201 and the distillation tower 202. The medium in the cooling pipeline 7 is preferably part of the air that has been deep-cooled by the turbine expander 201. The part of the air transfers the cooling energy generated by the turbine expander 201 to the deep-cooling device and then enters the distillation tower 202 to be separated.

[0063] The cryogenic device includes a second gas supply pipeline 601 and a cryogenic tower 602. The second gas supply pipeline 601 connects the anode mixed gas outlet 502 and the cryogenic tower 602, and the second gas supply pipeline 601 has a mixed gas compressor and a mixed gas expander. The mixed gas discharged from the anode mixed gas outlet 502 is first compressed by the mixed gas compressor to increase the pressure, then expanded and cooled by the mixed gas expander, and finally enters the cryogenic tower 602 for separation. It can be understood that in other embodiments, the mixed gas expander may not be provided on the second gas supply pipeline 601.

[0064] The cryogenic device also includes a heat exchanger 603 and a condenser evaporator. The heat exchanger 603 is arranged outside the cryogenic tower 602, and the heat exchanger 603 is connected to the cooling pipeline 7 and the second gas supply pipeline 601. The connection between the heat exchanger 603 and the second gas supply pipeline 601 is located downstream of the mixed gas compressor and the mixed gas expander. The gas medium in the cooling pipeline 7 and the mixed gas in the second gas supply pipeline 601 exchange heat in the heat exchanger 603, so that the cold capacity of the gas medium in the cooling pipeline 7 is used to pre-cool the mixed gas in the second gas supply pipeline 601. The pre-cooled mixed gas enters the cryogenic tower 602 through the second gas supply pipeline 601. The condenser evaporator is arranged at the upper end of the interior of the cryogenic tower 602, and the condenser evaporator is connected to the cooling pipeline 7 so that the gas medium in the cooling pipeline 7 can exchange heat with the mixed gas in the cryogenic tower 602, and the mixed gas in the cryogenic tower 602 is mainly cooled by the condenser evaporator. The rising gas in the cryogenic tower 602 is condensed to form a reflux liquid under the action of the condenser evaporator and forms a condensation and evaporation process with the rising gas, so that the oxygen concentration in the rising gas continues to increase, and the concentration of carbon dioxide in the descending condensed liquid continues to increase, and finally oxygen is obtained at the top of the cryogenic tower 602 and liquid carbon dioxide is obtained at the bottom, and oxygen and liquid carbon dioxide are discharged from the corresponding exhaust ports of the cryogenic tower 602, thereby producing oxygen through the separation operation of the cryogenic tower 602 to increase the oxygen lifting capacity of the air separation system.

[0065] It is understandable that the cryogenic device is not limited to having both a heat exchanger and a condenser evaporator. For example, in some other embodiments, the cryogenic device does not have a heat exchanger, and the mixed gas discharged from the anode mixed gas outlet is directly supplied into the cryogenic tower through the second gas supply pipeline, and gas separation is achieved under the action of the condenser evaporator; or the cryogenic device does not have a condenser evaporator, and the mixed gas discharged from the anode mixed gas outlet is cooled and condensed by the heat exchanger in the process of being supplied into the cryogenic tower through the second gas supply pipeline, and then separation is achieved in the cryogenic tower due to the different evaporation temperatures of each component. In this case, the cryogenic tower is essentially a distillation tower.

[0066] In some embodiments, the distillation tower 202 has a contaminated nitrogen gas discharge pipeline 203, which is connected to the molecular sieve purifier 1, so that the molecular sieve purifier 1 receives the contaminated nitrogen gas and desorbs and discharges carbon dioxide. The molecular sieve purifier 1 has a carbon dioxide discharge port 101, which is connected to the atmosphere, or the carbon dioxide discharge port 101 is connected to the alkali liquid capture device 3 through the first gas supply pipeline 4.

[0067] like Figure 1-Figure 3As shown, the distillation tower 202 has a contaminated nitrogen gas exhaust pipeline 203, and the outlet end of the contaminated nitrogen gas exhaust pipeline 203 is connected to the molecular sieve purifier 1, so as to regenerate the molecular sieve purifier 1 with the contaminated nitrogen gas separated by the distillation tower 202, and desorb the carbon dioxide adsorbed by the molecular sieve purifier 1 during the regeneration process. The molecular sieve purifier 1 has a carbon dioxide exhaust port 101, and the desorbed carbon dioxide is discharged from the carbon dioxide exhaust port 101.

[0068] In such Figure 1 and Figure 2 In the embodiment shown, the alkali liquid capture device 3 is arranged upstream of the molecular sieve purifier 1, and the carbon dioxide in the air is mainly absorbed and captured by the alkali liquid capture device 3, so the molecular sieve purifier 1 absorbs and captures less carbon dioxide. Figure 1 In the embodiment shown, the carbon dioxide discharge port 101 is connected to the alkali liquid capture device 3 through the first air supply pipeline 4, and the carbon dioxide adsorbed and captured by the molecular sieve purifier 1 enters the alkali liquid capture device 3 after desorption, so that all the carbon dioxide in the air is finally absorbed and captured by the alkali liquid in the alkali liquid capture device 3 for utilization; Figure 2 In the illustrated embodiment, the carbon dioxide exhaust port 101 is connected to the atmosphere, and the desorbed carbon dioxide is directly discharged into the atmosphere.

[0069] In such Figure 3 In the described embodiment, the carbon dioxide exhaust port 101 is connected to the alkali solution capture device 3 through the first air supply pipeline 4, and the carbon dioxide in the air is adsorbed and captured by the molecular sieve purifier 1. Therefore, the molecular sieve purifier 1 adsorbs and captures more carbon dioxide, and the desorbed carbon dioxide is supplied to the alkali solution capture device 3 through the first air supply pipeline 4, and is absorbed and captured again under the action of the alkali solution for utilization.

[0070] It is understandable that the distillation tower is not limited to having a nitrogen exhaust pipeline. In other embodiments, the distillation tower directly discharges the generated nitrogen into the atmosphere, and a storage device for storing nitrogen separately is provided to provide nitrogen to the molecular sieve purifier for regeneration.

[0071] In some embodiments, the molecular sieve purifier 1 has an air inlet and a dirty nitrogen inlet that can be opened and closed alternately, and the dirty nitrogen inlet is connected to the dirty nitrogen exhaust pipeline 203. The molecular sieve purifier 1 has an adsorption circuit and a desorption circuit. In the adsorption state, the air inlet is opened and the dirty nitrogen inlet is closed. In the desorption state, the air inlet is closed and the nitrogen inlet is opened. The molecular sieve purifiers 1 are at least two in parallel, at least one of which is in the adsorption state, and at least one of which is in the desorption state.

[0072] like Figure 1-Figure 3As shown, the molecular sieve purifier 1 has an air inlet and a dirty nitrogen inlet which can be opened and closed alternately. The dirty nitrogen inlet is connected to the dirty nitrogen exhaust pipeline 203 to receive the dirty nitrogen provided by the distillation tower 202. Figure 1 and Figure 2 In the embodiment shown, the air inlet is connected to the alkali liquid capture device 3 to receive the air after the alkali liquid capture device 3 captures the carbon dioxide. Figure 3 In the illustrated embodiment, the molecular sieve purifier 1 is located between the air source and the alkali solution capturing device 3 so that the air inlet receives the air provided by the air source.

[0073] like Figure 1-Figure 3 As shown, the molecular sieve purifier 1 has an adsorption state and a desorption state. In the adsorption state, the air inlet is open and the contaminated nitrogen inlet is closed, the molecular sieve purifier 1 receives air and adsorbs carbon dioxide in the air, and the molecular sieve purifier 1 does not receive contaminated nitrogen; in the desorption state, the air inlet is closed and the contaminated nitrogen inlet is open, the molecular sieve purifier 1 does not receive air, and the molecular sieve purifier 1 receives contaminated nitrogen to desorb and release the adsorbed carbon dioxide through the contaminated nitrogen to achieve regeneration. The molecular sieve purifier 1 is set to be at least two in parallel, preferably two, one of which is in the adsorption state and the other is in the desorption state, and the state is switched at intervals to always have one molecular sieve purifier 1 adsorbing carbon dioxide. In the case of Figure 1 and Figure 2 In the illustrated embodiment, since the alkali solution capturing device 3 is located upstream of the molecular sieve purifier 1 and most of the carbon dioxide is absorbed and captured by the alkali solution capturing device 3 , the switching interval of the molecular sieve purifier 1 is also prolonged.

[0074] It is understandable that the number of molecular sieve purifiers is not limited to at least two. In other embodiments, only one molecular sieve purifier is provided, and when the molecular sieve purifier is in a desorption state, the air source stops supplying gas.

[0075] In some embodiments, the alkali liquid collecting device 3 has a liquid supply port at the top and a liquid discharge port at the bottom.

[0076] Specifically, Figure 1-Figure 3 As shown, the alkali liquid capture device 3 is an alkali liquid spray tower, and the top of the alkali liquid spray tower is provided with an exhaust port, a liquid supply port and a spray device, the liquid supply port is connected to the spray device to provide alkali liquid to the spray device, and the spray device sprays alkali liquid, such as sodium hydroxide solution and potassium hydroxide solution, in the alkali liquid spray tower. The bottom of the alkali liquid spray tower is provided with an air inlet and a liquid discharge port; Figure 1 and Figure 2In the embodiment shown, the alkali liquid spray tower is located between the air source and the molecular sieve purifier 1, so that the air inlet receives the air provided by the air source, and the air flows upward after entering the interior of the alkali liquid spray tower, and contacts with the sprayed alkali liquid during the flow, so that the carbon dioxide in the air is absorbed and captured by the alkali liquid, and the air after the carbon dioxide is captured is discharged from the exhaust port at the top and supplied to the molecular sieve purifier 1; in the embodiment shown in FIG. Figure 3 In the embodiment shown, the air inlet is connected to the first air supply pipeline 4 to receive the carbon dioxide desorbed by the molecular sieve purifier 1, and the carbon dioxide enters the alkali solution spray tower and flows upward, and contacts with the sprayed alkali solution during the flow, so that it is absorbed and captured by the alkali solution. After the capture, the remaining impurity gas and a small amount of carbon dioxide are directly discharged into the atmosphere from the exhaust port at the top; Figure 1-Figure 3 As shown, the alkali solution after absorbing and capturing carbon dioxide falls and accumulates at the bottom of the alkali solution spray tower, and is discharged through the drain port and supplied to the electrolytic cell 5 for electrolysis.

[0077] The electrolytic cell 5 also has a liquid outlet 504. Specifically, Figure 1-Figure 3 As shown, the electrolytic cell 5 also has a liquid outlet 504, which is located on the cathode side of the electrolytic cell 5. The liquid after absorbing and capturing carbon dioxide is electrolyzed in the electrolytic cell 5. While generating a mixed gas and hydrogen, regenerated alkaline solution is also generated. The regenerated alkaline solution is discharged from the electrolytic cell 5 through the liquid outlet 504.

[0078] The air separation system also includes a liquid supply pipeline 8, a circulation pipeline 9 and a regeneration liquid pipeline 10. The liquid supply pipeline 8 connects the liquid discharge port and the liquid inlet 501, the circulation pipeline 9 connects the liquid discharge port and the liquid supply port, and the regeneration liquid pipeline 10 connects the liquid outlet 504 and the liquid supply port.

[0079] Specifically, Figure 1-Figure 3 As shown, the air separation system further includes a liquid supply pipeline 8, a circulation pipeline 9 and a regeneration liquid pipeline 10. The liquid supply pipeline 8 is connected to the liquid discharge port and the liquid inlet 501, and the circulation pipeline 9 is connected to the liquid discharge port and the liquid supply port. Preferably, the inlet end of the circulation pipeline 9 is arranged on the liquid supply pipeline 8. Since the amount of alkali liquid sprayed in the alkali liquid capture device 3 is large, the alkali liquid cannot fully react with carbon dioxide in a single spraying. Therefore, most of the liquid discharged from the liquid discharge port is supplied to the liquid supply port through the circulation pipeline 9 to recycle the alkali liquid and absorb carbon dioxide as much as possible. A small portion of the liquid discharged from the discharge port is supplied to the liquid inlet 501 through the liquid supply pipeline 8 to enter the electrolytic cell 5 for electrolysis. At the same time, since the alkali solution is recycled through the circulation pipeline 9, the liquid supplied to the electrolytic cell 5 absorbs more carbon dioxide, so the electrolysis can produce more products. The regeneration liquid pipeline 10 connects the liquid outlet 504 and the liquid supply port. The alkali solution regenerated by electrolysis is supplied to the liquid supply port through the regeneration liquid pipeline 10 to realize the recycling of the alkali solution. Preferably, the outlet end of the circulation pipeline 9 is arranged on the regeneration liquid pipeline 10.

[0080] It is understandable that the air separation system is not limited to having a liquid supply pipeline, a circulation pipeline and a regeneration liquid pipeline. In other embodiments, the air separation system does not have a circulation pipeline, and the liquid discharged from the drain port of the alkali liquid capture device all enters the electrolytic cell for electrolysis.

[0081] In some embodiments, the air separation system of the embodiment of the present invention further includes a compressor 11 , the molecular sieve purifier 1 is connected to the compressor 11 and is located downstream of the compressor 11 , and the compressor 11 is used to compress air and supply the compressed air to the molecular sieve purifier 1 .

[0082] In such Figure 1 In the illustrated embodiment, the compressor 11 is connected between the alkali liquid collection device 3 and the molecular sieve purifier 1 , and the compressor 11 is located upstream of the molecular sieve purifier 1 , and the air discharged from the alkali liquid collection device 3 is supplied to the molecular sieve purifier 1 after being pressurized by the compressor 11 .

[0083] In such Figure 2 In the illustrated embodiment, the compressor 11 is connected between the alkali liquid capturing device 3 and the air source. The alkali liquid capturing device 3 is located upstream of the molecular sieve purifier 1. The air provided by the air source is pressurized by the compressor 11 and supplied to the alkali liquid capturing device 3. The air reacts with the alkali liquid under high pressure and is discharged from the alkali liquid capturing device 3 under high pressure and supplied to the molecular sieve purifier 1.

[0084] In such Figure 3 In the illustrated embodiment, the compressor 11 is connected between the air source and the molecular sieve purifier 1 , and the air provided by the air source is supplied to the molecular sieve purifier 1 after being pressurized by the compressor 11 .

[0085] In some embodiments, the alkali liquid collection device 3 is connected between the compressor 11 and the molecular sieve purifier 1; or the air separation system also includes an air cooler 12, the air cooler 12 is connected between the compressor 11 and the molecular sieve purifier 1, and the alkali liquid collection device 3 is located upstream of the compressor 11, or the alkali liquid collection device 3 is connected to the molecular sieve purifier 1 through the first air supply pipeline 4.

[0086] In such Figure 1 and Figure 3 In the embodiment shown, the air separation system further includes an air cooler 12, which is connected between the compressor 11 and the molecular sieve purifier 1, and the air cooler 12 is located downstream of the compressor 11. The air pressurized by the compressor 11 is cooled when passing through the air cooler 12. The alkali liquid capture device 3 can be as follows Figure 1 The compressor 11 is connected to the compressor 11 and is located upstream of the compressor 11. Figure 3 As shown, it is connected to the molecular sieve purifier 1 through the first gas supply pipeline 4.

[0087] In such Figure 2 In the illustrated embodiment, the alkali liquid capture device 3 is connected between the compressor 11 and the molecular sieve purifier 1, and the alkali liquid capture device 3 is located downstream of the compressor 11. At this time, the alkali liquid capture device 3 has not only the function of absorbing and capturing carbon dioxide but also the function of air cooling. The air compressed by the compressor 11 will be cooled during the flow in the alkali liquid capture device 3, so there is no need to set up an air cooler 12.

[0088] In some embodiments, the air separation system of the embodiment of the present invention also includes an air cleaner 13, the compressor 11 is located upstream of the alkali liquid capture device 3, the air cleaner 13 is connected to the compressor 11, and the air cleaner 13 is located upstream of the compressor 11; or the alkali liquid capture device 3 is located upstream of the compressor 11, the air cleaner 13 is connected to the alkali liquid capture device 3, and the air cleaner 13 is located upstream of the alkali liquid capture device 3.

[0089] like Figure 1-Figure 3 As shown, the air cleaner 13 is directly connected to the air source, and the air provided by the air source first passes through the air cleaner 13 to remove impurities such as dust particles. Figure 1 In the embodiment shown, the air impurity remover 13 is connected to the alkali liquid collecting device 3, and the air impurity remover 13 is located upstream of the alkali liquid collecting device 3, and the alkali liquid collecting device 3 is located upstream of the compressor 11. Figure 2 and Figure 3 In the illustrated embodiment, the air cleaner 13 is in communication with the compressor 11 , and the air cleaner 13 is located upstream of the compressor 11 .

[0090] In some embodiments, the air separation system of the embodiment of the present invention further includes a blower 14, such as Figure 1 As shown, the blower 14 is directly connected to the air cleaner 13 and is located downstream of the air cleaner 13 , and the blower 14 provides power for air flow.

[0091] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for distinction, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0092] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0093] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0094] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0095] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. An air separation system with carbon dioxide capture function, characterized in that: include: A molecular sieve purifier (1), wherein the molecular sieve purifier (1) is used to receive air and adsorb carbon dioxide in the air; a first separation device (2), the first separation device (2) being connected to the molecular sieve purifier (1) for separating the air discharged from the molecular sieve purifier (1) and generating oxygen and nitrogen, the first separation device (2) comprising a turbine expander (201) and a distillation tower (202), the turbine expander (201) being connected to the molecular sieve purifier (1) for deep cooling the air discharged from the molecular sieve purifier (1), the distillation tower (202) being connected to the turbine expander (201) for separating the deep cooled air and generating oxygen and nitrogen; an alkali liquid capture device (3), the alkali liquid capture device (3) being arranged upstream of the molecular sieve purifier (1) to capture carbon dioxide in the air and discharge the captured air to the molecular sieve purifier (1), and / or the alkali liquid capture device (3) being connected to the molecular sieve purifier (1) via a first air supply pipeline (4) to obtain carbon dioxide discharged by desorption from the molecular sieve purifier (1); An electrolytic cell (5), the electrolytic cell (5) having a liquid inlet (501), an anode mixed gas outlet (502) and a cathode hydrogen outlet (503), the liquid inlet (501) of the electrolytic cell (5) being in communication with the alkali liquid collecting device (3) so that the electrolytic cell (5) can obtain the liquid discharged from the alkali liquid collecting device (3) and perform electrolysis; The second separation device (6) is connected to the anode mixed gas outlet (502) of the electrolytic cell (5) to obtain the mixed gas discharged from the anode mixed gas outlet (502) and separate it to produce oxygen and carbon dioxide. The second separation device (6) is a cryogenic device.

2. The air separation system with carbon dioxide capture function according to claim 1, characterized in that: The air separation system further comprises a cooling pipeline (7), wherein the cooling pipeline (7) connects the cryogenic device and the turbine expander (201), so that the medium in the cooling pipeline (7) transfers the cooling energy generated by the turbine expander (201) to the cryogenic device.

3. The air separation system with carbon dioxide capture function according to claim 2, characterized in that: The cooling pipeline (7) is in communication with the turbine expander (201) and the distillation tower (202); The cryogenic device comprises: A second gas supply pipeline (601), one end of the second gas supply pipeline (601) being in communication with the anode mixed gas outlet (502); a cryogenic tower (602), the cryogenic tower (602) being in communication with the other end of the second gas supply pipeline (601), so that the cryogenic tower (602) can obtain the mixed gas discharged from the anode mixed gas outlet (502) and separate the mixed gas into oxygen and carbon dioxide; The cryogenic device also includes: a heat exchanger (603), the heat exchanger (603) being arranged outside the cryogenic tower (602), and the heat exchanger (603) being connected to the cooling pipeline (7) and the second gas supply pipeline (601) so as to be used for heat exchange between the medium in the cooling pipeline (7) and the mixed gas in the second gas supply pipeline (601); and / or A condenser evaporator is arranged inside the cryogenic tower (602), and the condenser evaporator is connected to the cooling pipeline (7) to be used for heat exchange between the medium in the cooling pipeline (7) and the mixed gas in the cryogenic tower (602).

4. The air separation system with carbon dioxide capture function according to claim 1, characterized in that: The distillation tower (202) has a contaminated nitrogen gas discharge pipeline (203), and the contaminated nitrogen gas discharge pipeline (203) is connected to the molecular sieve purifier (1), so that the molecular sieve purifier (1) receives the contaminated nitrogen gas and desorbs and discharges carbon dioxide; The molecular sieve purifier (1) has a carbon dioxide discharge port (101), and the carbon dioxide discharge port (101) is connected to the atmosphere, or the carbon dioxide discharge port (101) is connected to the alkali liquid capture device (3) through the first gas supply pipeline (4).

5. The air separation system with carbon dioxide capture function according to claim 4, characterized in that: The molecular sieve purifier (1) has an air inlet and a dirty nitrogen inlet which can be opened and closed alternately, the dirty nitrogen inlet is connected to the dirty nitrogen exhaust pipeline (203), the molecular sieve purifier (1) has an adsorption state and a desorption state, in the adsorption state, the air inlet is opened and the dirty nitrogen inlet is closed, in the desorption state, the air inlet is closed and the dirty nitrogen inlet is opened, the molecular sieve purifier (1) is at least two in parallel, at least one of the molecular sieve purifiers (1) is in the adsorption state, and at least one of the molecular sieve purifiers (1) is in the desorption state.

6. The air separation system with carbon dioxide capture function according to any one of claims 1 to 5, characterized in that: The alkali liquid collecting device (3) has a liquid supply port located at the top and a liquid discharge port located at the bottom; The electrolytic cell (5) also has a liquid outlet (504); The air separation system also includes: a liquid supply pipeline (8), wherein the liquid supply pipeline (8) is connected to the liquid discharge port and the liquid inlet (501); A circulation pipeline (9), wherein the circulation pipeline (9) is connected with the liquid discharge port and the liquid supply port; A regeneration liquid pipeline (10), wherein the regeneration liquid pipeline (10) is connected to the liquid outlet (504) and the liquid supply port.

7. The air separation system with carbon dioxide capture function according to any one of claims 1 to 5, characterized in that: It also comprises a compressor (11), the molecular sieve purifier (1) is connected to the compressor (11) and is located downstream of the compressor (11), and the compressor (11) is used to compress air and supply the compressed air to the molecular sieve purifier (1).

8. The air separation system with carbon dioxide capture function according to claim 7, characterized in that: The alkali liquid collection device (3) is connected between the compressor (11) and the molecular sieve purifier (1); or The air separation system further comprises an air cooler (12), wherein the air cooler (12) is connected between the compressor (11) and the molecular sieve purifier (1), and the alkali liquid collection device (3) is located upstream of the compressor (11), or the alkali liquid collection device (3) is connected to the molecular sieve purifier (1) via the first air supply pipeline (4).

9. The air separation system with carbon dioxide capture function according to claim 8, characterized in that: It also includes an air impurity remover (13), the compressor (11) is located upstream of the alkali liquid collection device (3), the air impurity remover (13) is communicated with the compressor (11), and the air impurity remover (13) is located upstream of the compressor (11); or The alkali liquid collecting device (3) is located upstream of the compressor (11), the air impurity remover (13) is connected to the alkali liquid collecting device (3), and the air impurity remover (13) is located upstream of the alkali liquid collecting device (3).

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