Carbon dioxide trapping system
By adopting chemical absorption method and heat pump unit in the carbon dioxide capture system, combined with a multi-stage heat exchange device, the problems of large energy consumption and low capture efficiency in the prior art are solved, and the efficient and low energy consumption carbon dioxide capture effect is achieved.
Patent Information
- Application Number
- CN202420083786.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-12
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-01-12
AI Technical Summary
The existing carbon dioxide capture technology has problems such as large energy consumption, high operating costs, and poor CO2 capture efficiency and capture effect.
Adopt a carbon dioxide capture system including an absorption unit, a desorption unit, a phase separation unit, a liquid lean reuse unit and a heat pump unit to absorb and desorption through a phase change absorber in a chemical absorption method, and use a heat pump unit to reduce desorption energy consumption , and improve the CO2 capture efficiency through a multi-stage heat exchange device.
It realizes efficient and low-energy-consuming carbon dioxide capture, and produces stable and high-purity products, significantly reducing operating energy consumption and operating costs.
Smart Images
Figure CN222173594U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of carbon dioxide capture, and in particular to a carbon dioxide capture system. Background Art
[0002] At present, the carbon dioxide capture technology adopts activated carbon adsorption and distillation, condensation, membrane concentration, ammonia solution absorption, carbonate absorption, organic amine liquid absorption and other technical means. Among them, the adsorption efficiency of activated carbon adsorption and distillation method is high. A multi-stage water separation system and a drying tower are set before the activated carbon adsorption. A refrigerator, a distillation tower, a reboiler, etc. are also set after the adsorption tower. The system process is long, the number of towers required is large, the overall equipment occupies a large area, the activated carbon bed is easy to clog, and the energy consumption caused by refrigeration and reboiling is high; the condensation method can obtain gas associated gas products while obtaining carbon dioxide by setting a refrigeration unit, but the condensation point of carbon dioxide is -78.5℃, and the required investment and operating energy consumption are high; membrane filtration concentration can selectively filter carbon dioxide or other target gases, It can be applied in liquid or gas phase, but the technology is not mature at present. The membrane components are not resistant to high temperature, and the pretreatment process is long. The membrane is easy to be blocked and damaged, and the replacement is frequent. The assembly is difficult, the volume is large, and the investment cost is high. The ammonia solution absorption method can absorb carbon dioxide through acid-base reaction. Since the generated ammonium carbonate and ammonium bicarbonate are weak acids that are easy to decompose, this method is a simple and easy method. However, since the decomposition reaction requires a lot of heat, the ammonia escape increases significantly, which not only causes the waste of ammonia water and reduces the purity of the discharged CO2 product gas, but also causes serious environmental pollution and poor operating environment. The reaction of carbonate solution absorbing carbon dioxide to generate bicarbonate is a reversible reaction in itself. There are many factors that are affected. It is difficult to control the absorption efficiency and desorption efficiency. The technology is immature. The method of using organic amine liquid for absorption is a common means of weak acid anhydride treatment. Usually, sterically hindered amines, alcohol amines, etc. are commonly used absorbents. The technology is relatively mature, but the disadvantage is that the steam consumption required for desorption is large and the operating cost of the device is high. Therefore, the existing carbon dioxide capture technology has the defects of high energy consumption, high operating cost, and poor CO2 capture efficiency and capture effect.
[0003] In view of this, the present utility model is proposed. Utility Model Content
[0004] One purpose of the utility model is to provide a carbon dioxide capture system, which can not only absorb and capture carbon dioxide in large quantities and efficiently, turning it into a stable product with high purity, but also significantly reduce operating energy consumption.
[0005] In order to achieve the above-mentioned purpose of the utility model, the following technical solutions are adopted:
[0006] A carbon dioxide capture system comprises an absorption unit, a desorption unit, a phase separation unit, a lean liquid recycling unit, a heat exchange unit and a heat pump unit;
[0007] The absorption unit includes an absorption device; the desorption unit includes a desorption device; the phase separation unit includes a phase separation device; the lean liquid recycling unit includes a mixing device and a cooling device; the heat exchange unit includes a lean and rich liquid heat exchange device; the heat pump unit includes a desorption lean liquid heat exchange device and a reboiling device;
[0008] The rich liquid outlet of the absorption device is connected with the rich liquid inlet of the phase separation device; the light phase outlet of the phase separation device is connected with the lean liquid recovery port of the absorption device through the mixing device and the cooling device; the heavy phase outlet of the phase separation device is connected with the rich liquid inlet of the desorption device through the lean-rich liquid heat exchange device; the desorption lean liquid outlet of the desorption device is connected with the lean liquid inlet of the mixing device through the desorption lean liquid heat exchange device and the lean-rich liquid heat exchange device; the desorption lean liquid heat exchange device is connected with the reboiling device through a heating medium circulation loop; the reboiling device is connected with the desorption device through a gas-liquid phase circulation loop.
[0009] In one embodiment, the absorption device is provided with an absorption filler layer, a first nozzle and a first demister, and the first nozzle is arranged on the upper part of the absorption filler layer; the absorption device is provided with a flue gas inlet to be purified, an absorbent inlet and a purified flue gas outlet; the absorbent inlet is connected to the nozzle; the flue gas inlet to be purified is located below the absorption filler layer; the purified flue gas outlet is located at the top of the absorption device; the rich liquid outlet of the absorption device is located at the bottom of the absorption device.
[0010] In one embodiment, the heating medium circulation loop includes a hot medium pipeline and a cold medium pipeline; the inlet of the hot medium pipeline is connected to the medium outlet of the desorption lean liquid heat exchange device, and the outlet of the hot medium pipeline is connected to the medium inlet of the reboiling device; along the inlet to the outlet direction of the hot medium pipeline, a compression device and a temporary heating device are sequentially arranged on the hot medium pipeline; the inlet of the cold medium pipeline is connected to the reboiling device, and the outlet of the cold medium pipeline is connected to the medium inlet of the desorption lean liquid heat exchange device; an expansion joint is arranged on the cold medium pipeline.
[0011] In one embodiment, the desorption unit further includes a condensing device and a reflux device; the top gas outlet of the desorption device is connected to the inlet of the reflux device through the condensing device; the liquid phase outlet of the reflux device is connected to the top inlet of the desorption device through a reflux pump.
[0012] In one embodiment, the desorption device is provided with a first desorption zone, a second desorption zone, a second nozzle and a second demister; along the direction from the bottom to the top of the desorption device, the first desorption zone and the second desorption zone are sequentially arranged inside the desorption device, the first desorption zone includes at least one first treatment layer, which is sequentially a first catalyst layer and a first filler layer, and the second desorption zone includes at least one second treatment layer, which is sequentially a second catalyst layer and a second filler layer.
[0013] In one embodiment, the rich liquid inlet of the desorption device includes a middle rich liquid inlet and a top rich liquid inlet, the middle rich liquid inlet is located between the first desorption zone and the second desorption zone; the top rich liquid inlet is located at the upper part of the second desorption zone; the rich liquid outlet of the lean-rich liquid heat exchange device is connected to the middle rich liquid inlet and the top rich liquid inlet through a three-way pipeline.
[0014] In one embodiment, the lean liquid recycling unit also includes a lean liquid cache device, a filtering device and a purification device; a main pipeline is arranged between the mixing device and the cooling device; the lean liquid cache device is connected to the main pipeline through a side circulation pipeline; the lean liquid cache device is connected to the filtering device and the purification device in sequence.
[0015] In one embodiment, a lean liquid pump is provided on the main pipeline; and a liquid return pump is provided on the side circulation pipeline.
[0016] In one embodiment, the absorption device and the phase separation device are connected via a rich liquid pump.
[0017] In one embodiment, the heavy phase outlet of the phase separation device is connected to the rich liquid inlet of the lean-rich liquid heat exchange device through a heavy phase pump.
[0018] Compared with the prior art, the beneficial effects of the utility model are:
[0019] The carbon dioxide capture system of the utility model can absorb and capture carbon dioxide in large quantities and efficiently through the cooperation of various units to turn it into a stable product with high purity, and can also significantly reduce operating energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0021] Figure 1 A schematic diagram of a carbon dioxide capture system of the present invention;
[0022] Figure 2 This is a schematic diagram of the structure of the absorption device of the utility model;
[0023] Figure 3 It is a structural schematic diagram of the desorption device of the utility model.
[0024] Reference numerals:
[0025] 1-absorption device, 101-absorption packing layer, 102-first nozzle, 103-first demister, 2-desorption device, 201-first desorption zone, 2011-first catalyst layer, 2012-first packing layer, 202-second desorption zone, 2021-second catalyst layer, 2022-second packing layer, 203-second nozzle, 204-second demister, 3-phase separation device, 4-mixing device, 5-cooling device, 6-lean and rich liquid heat exchange device, 7-desorption lean liquid heat exchange device, 8-reboiling device, 9-compression device, 10-temporary heating device, 11-expansion joint, 12-condensing device, 13-reflux device, 14-lean liquid buffer device, 15-filtering device, 16-purification device, 17-lean liquid pump, 18-return liquid pump, 19-rich liquid pump, 20-heavy phase pump. DETAILED DESCRIPTION
[0026] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0027] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0028] The utility model relates to a carbon dioxide capture system, comprising an absorption unit, a desorption unit, a phase separation unit, a lean liquid recycling unit, a heat exchange unit and a heat pump unit;
[0029] The absorption unit includes an absorption device; the desorption unit includes a desorption device; the phase separation unit includes a phase separation device; the lean liquid recycling unit includes a mixing device and a cooling device; the heat exchange unit includes a lean and rich liquid heat exchange device; the heat pump unit includes a desorption lean liquid heat exchange device and a reboiling device;
[0030] The rich liquid outlet of the absorption device is connected with the rich liquid inlet of the phase separation device; the light phase outlet of the phase separation device is connected with the lean liquid recovery port of the absorption device through the mixing device and the cooling device; the heavy phase outlet of the phase separation device is connected with the rich liquid inlet of the desorption device through the lean-rich liquid heat exchange device; the desorption lean liquid outlet of the desorption device is connected with the lean liquid inlet of the mixing device through the desorption lean liquid heat exchange device and the lean-rich liquid heat exchange device; the desorption lean liquid heat exchange device is connected with the reboiling device through a heating medium circulation loop; the reboiling device is connected with the desorption device through a gas-liquid phase circulation loop.
[0031] The carbon dioxide capture system of the utility model can realize efficient absorption and desorption of carbon dioxide through the cooperation of various units, and can significantly reduce energy consumption.
[0032] The carbon dioxide capture system adopts the phase change absorbent in the chemical absorption method for absorption and desorption. The absorbent absorbs CO2 and reacts to automatically separate into layers. Only the lower heavy phase is used for the desorption device. Since the desorption reduces the heating and gasification of the solvent, the desorption energy consumption will be greatly reduced. The desorption device can increase the rate of desorption and release of CO2, and at the same time reduce the desorption temperature, so that the amine liquid temperature can be desorbed at a temperature below 90°C, without the need for solvent gasification, further reducing the desorption energy consumption. Since the desorption device does not require complete gasification for desorption, the operating pressure and design pressure of the desorption tower are reduced, so the wall thickness and reinforcement of the desorption tower can be reduced; the desorption temperature is reduced, the gas phase composition is reduced, and the corrosiveness during desorption is reduced, so the material standard of the desorption device can also be reduced, and the engineering construction cost of the desorption device can be greatly reduced. Since the desorption temperature is lower than 90°C, the heat pump unit can provide desorption heat for the desorption tower. During normal operation, the process of heating and desorption of the rich amine liquid requires almost no external energy.
[0033] In one embodiment, the rich liquid outlet of the absorption device is connected to the rich liquid inlet of the phase separation device; the light phase outlet of the phase separation device is connected to the lean liquid inlet of the mixing device, and the lean liquid outlet of the mixing device is connected to the lean liquid recovery port of the absorption device through the cooling device; the heavy phase outlet of the phase separation device is connected to the cold side inlet of the lean-rich liquid heat exchange device; the cold side outlet of the lean-rich liquid heat exchange device is connected to the lean liquid inlet of the mixing device, the rich liquid outlet of the lean-rich liquid heat exchange device is connected to the rich liquid inlet of the desorption device, and the hot side inlet of the lean-rich liquid heat exchange device is connected to the lean liquid outlet of the desorption lean liquid heat exchange device; the lean liquid inlet of the desorption lean liquid heat exchange device is connected to the lean liquid outlet of the desorption device; the desorption lean liquid heat exchange device is connected to the reboiler through a heating medium circulation loop; the reboiler is connected to the desorption device through a gas-liquid phase circulation loop.
[0034] In one embodiment, the absorbent treats the flue gas to be purified in the absorption device. The absorption device is provided with an absorption packing layer, a first nozzle and a first demister inside, and the first nozzle is arranged on the upper part of the absorption packing layer; the absorption device is provided with a flue gas inlet to be purified, an absorbent inlet and a purified flue gas outlet; the absorbent inlet is connected to the nozzle; the flue gas inlet to be purified is located below the absorption packing layer; the purified flue gas outlet is located at the top of the absorption device; the rich liquid outlet of the absorption device is located at the bottom of the absorption device. The absorption device is an absorption tower. The flue gas to be purified containing CO2 enters the absorption device from the flue gas inlet to be purified, and the absorbent enters the absorption device from the absorbent inlet, and is sprayed through the first nozzle. The flue gas to be purified contacts the organic absorbent sprayed from top to bottom in reverse direction, and the CO2 in the flue gas reacts with the absorbent to generate organic salts, which are captured, and the flue gas with CO2 removed is discharged into the atmosphere or to a designated location from the purified flue gas outlet of the absorption device after water washing and demisting. The filler in the absorption packing layer is a conventional filler in the prior art.
[0035] In one embodiment, after the absorbent absorbs CO2, part of it turns into organic salts, and part of it maintains an organic state to become rich liquid, and the rich liquid is discharged from the absorption device. The absorption device and the phase separation device are connected through a rich liquid pump. The rich liquid generated by the absorption device enters the phase separation device through the rich liquid pump for phase separation, the light phase enters the mixing device, and the heavy phase enters the lean-rich liquid heat exchange device through the heavy phase pump, and then enters the desorption device for desorption treatment. The phase separation device adopts a conventional phase separator. In one embodiment, the heavy phase outlet of the phase separation device is connected to the rich liquid inlet of the lean-rich liquid heat exchange device through a heavy phase pump; the lean liquid outlet of the phase separation device is connected to the lean liquid inlet of the mixing device through a light phase pump.
[0036] In one embodiment, the lean-rich liquid heat exchange unit can realize heat exchange between the heavy phase and the desorbed lean liquid generated from the desorption device. The heavy phase is heated by the desorbed lean liquid in the lean-rich liquid heat exchange device to become a hot heavy phase, and the hot heavy phase enters the desorption device for desorption. The desorbed lean liquid is further cooled in the lean-rich liquid heat exchange device, and then enters the mixing device to be mixed with the light phase generated by the phase separation device.
[0037] In one embodiment, the desorption unit is used for desorption treatment of the thermogravimetric phase and collection of carbon dioxide gas products. In one embodiment, the desorption device is provided with a first desorption zone, a second desorption zone, a second nozzle and a second demister; along the direction from the bottom to the top of the desorption device, the first desorption zone and the second desorption zone are sequentially arranged inside the desorption device, the first desorption zone includes at least one first treatment layer, the first treatment layer is sequentially a first catalyst layer and a first filler layer, the second desorption zone includes at least one second treatment layer, the second treatment layer is sequentially a second catalyst layer and a second filler layer.
[0038] In one embodiment, the rich liquid inlet of the desorption device includes a middle rich liquid inlet and a top rich liquid inlet, wherein the middle rich liquid inlet is located between the first desorption zone and the second desorption zone; the top rich liquid inlet is located at the upper part of the second desorption zone; a three-way pipeline is arranged between the rich liquid outlet of the lean-rich liquid heat exchange device and the rich liquid inlet of the desorption device; the two outlet ends of the three-way pipeline are respectively connected to the middle rich liquid inlet and the top rich liquid inlet. The top rich liquid inlet is connected to the second nozzle.
[0039] In one embodiment, the desorption unit further includes a condensing device and a reflux device; the top gas outlet of the desorption device is connected to the inlet of the reflux device through the condensing device; the liquid phase outlet of the reflux device is connected to the top inlet of the desorption device through a reflux pump. After the heavy phase is desorbed in the desorption device, the generated CO2 gas, water vapor, and organic gas phase substances are discharged from the top of the desorption device; after heat exchange through the top condensing device, the condensed water and organic gas phase substances are recovered to the reflux device, and further refluxed to the top of the desorption device; the CO2 product gas is discharged to a designated location. The desorbed lean liquid generated by the desorption unit further enters the heat pump unit for heat treatment.
[0040] In one embodiment, the first catalyst and the second catalyst in the analysis device are each independently a solid acid acidifier, and the molecular sieve ZSM-5 is used as a carrier, and a metal oxide that can provide proton acid, that is, Bronsted acid (B-acid) and Lewis acid (L-acid) acid sites is loaded on the carrier; the metal oxide is one or more of MoO3, V2O5, Cr2O3, TiO2, WO3, Ag2O, NiO, Nb2O5, MnO2, CuO, SiO2, Al2O3, ZrO2 and ZnO. The catalyst is prepared by impregnating the molecular sieve carrier with a metal oxide precursor solution and calcining it at a high temperature, and the calcination temperature is 200 to 600°C. The prepared metal oxide catalyst is fixed in a metal frame module, and the module is stacked in an orderly manner in a desorption tower. In one embodiment, the first catalyst and the second catalyst in the analysis device are each independently a conventional catalyst material in the prior art.
[0041] In one embodiment, the heat pump unit can be used to achieve heat treatment of the desorbed lean liquid and provide a heat source for the desorbed device. In one embodiment, the heating medium circulation loop includes a hot medium pipeline and a cold medium pipeline; the inlet of the hot medium pipeline is connected to the medium outlet of the desorbed lean liquid heat exchange device, and the outlet of the hot medium pipeline is connected to the medium inlet of the reboiling device; along the inlet to the outlet direction of the hot medium pipeline, a compression device and a temporary heating device are sequentially arranged on the hot medium pipeline; the inlet of the cold medium pipeline is connected to the reboiling device, and the outlet of the cold medium pipeline is connected to the medium inlet of the desorbed lean liquid heat exchange device; an expansion joint is arranged on the cold medium pipeline.
[0042] The material discharged from the bottom of the desorption device is the desorbed lean liquid organic absorbent. The desorbed lean liquid is in a gas-liquid two-phase state with a high temperature. It enters the desorbed lean liquid heat recovery device to exchange heat with the medium (water or heat-conducting salt / heat-conducting oil, etc.) circulating in the heat pump unit. The heat in the desorbed lean liquid is recovered, and the gas phase is completely converted into a liquid phase, and the temperature is reduced at the same time; the medium of the heat pump unit is heated and completely converted into gas by heat exchange with the desorbed lean liquid, and is compressed in the compression device to increase the temperature and pressure, and enters the reboiling device to heat the mixed liquid at the bottom of the desorption device to provide a desorption heat source. After passing through the reboiling device, the medium of the heat pump unit liquefies into a gas-liquid mixed phase, expands into gas through the expansion joint, and enters the desorbed lean liquid heat recovery device again, and is heated by the desorbed lean liquid to form a cycle. The temporary heater can be an electric heater or a steam heater. The above-mentioned medium can release or absorb a large amount of heat when a phase change occurs.
[0043] No external heat source is required during normal operation. However, when the system is debugged and started, if the heat after vaporization and compression of the medium in the heat pump unit is not enough to provide desorption heat, a temporary heating device can be used to supplement external heat to increase the heat.
[0044] In one embodiment, the lean liquid recycling unit can realize the recycling of lean liquid to the absorption device. The lean liquid recycling unit also includes a lean liquid buffer device, a filtering device and a purification device;
[0045] A main pipeline is provided between the mixing device and the cooling device; the lean liquid buffer device is connected to the main pipeline through a side circulation pipeline; the lean liquid buffer device is connected to a filtering device and a purifying device in sequence. In one embodiment, a lean liquid pump is provided on the main pipeline; and a liquid return pump is provided on the side circulation pipeline.
[0046] In one embodiment, the filtering device includes a plurality of filters, and the filter media of the plurality of filters are different, including metal sintered mesh filters and activated carbon filters. In one embodiment, the purification device includes a tank containing ion exchange resin and a backwash device, the purpose of which is to treat stable salt ions generated by the amine solution during operation. Part of the amine solution is discharged from the lean liquid buffer device to the filtering device for filtering treatment, and then enters the purification device for purification treatment after filtering.
[0047] The following is further explained in conjunction with specific embodiments.
[0048] Example 1
[0049] A carbon dioxide capture system, such as Figure 1 As shown, it includes an absorption unit, a desorption unit, a phase separation unit, a lean liquid recycling unit, a heat exchange unit and a heat pump unit; the absorption unit includes an absorption device 1; the desorption unit includes a desorption device 2, a condensation device 12 and a reflux device 13; the phase separation unit includes a phase separation device 3; the lean liquid recycling unit includes a mixing device 4, a cooling device 5, a lean liquid buffer device 14, a filtering device 15 and a purification device 16; the heat exchange unit includes a lean-rich liquid heat exchange device 6; the heat pump unit includes a desorption lean liquid heat exchange device 7 and a reboiling device 8.
[0050] The rich liquid outlet of the absorption device 1 is connected to the rich liquid inlet of the phase separation device 3 through a rich liquid pump 19; the lean liquid outlet of the phase separation device 3 is connected to the lean liquid inlet of the mixing device 4, and the lean liquid outlet of the mixing device 4 is connected to the lean liquid recovery port of the absorption device 1 through the cooling device 5; the rich liquid outlet of the phase separation device 3 is connected to the cold side inlet of the lean-rich liquid heat exchange device 6 through a heavy phase pump 20; the cold side outlet of the lean-rich liquid heat exchange device 6 is connected to the lean liquid inlet of the mixing device 4. The liquid inlet of the lean-rich liquid heat exchange device 6 is connected, the rich liquid outlet of the lean-rich liquid heat exchange device 6 is connected with the rich liquid inlet of the desorption device 2, the hot side inlet of the lean-rich liquid heat exchange device 6 is connected with the lean liquid outlet of the desorption lean liquid heat exchange device 7; the lean liquid inlet of the desorption lean liquid heat exchange device 7 is connected with the lean liquid outlet of the desorption device; the desorption lean liquid heat exchange device 7 is connected with the reboiler 8 through a heating medium circulation loop; the reboiler 8 is connected with the desorption device 2 through a gas-liquid phase circulation loop.
[0051] The structural schematic diagram of the absorption device 1 is as follows Figure 2 As shown, an absorption filler layer 101, a first nozzle 102 and a first demister 103 are arranged inside, and the first nozzle 102 is arranged on the upper part of the absorption filler layer 101; the absorption device 1 is provided with a flue gas inlet to be purified, an absorbent inlet and a purified flue gas outlet; the absorbent inlet is connected to the nozzle; the flue gas inlet to be purified is located below the absorption filler layer 101; the purified flue gas outlet is located at the top of the absorption device 1; the rich liquid outlet of the absorption device 1 is located at the bottom of the absorption device 1.
[0052] The heating medium circulation loop includes a hot medium pipeline and a cold medium pipeline; the inlet of the hot medium pipeline is connected to the medium outlet of the desorption lean liquid heat exchange device 7, and the outlet of the hot medium pipeline is connected to the medium inlet of the reboiling device 8; along the inlet to the outlet direction of the hot medium pipeline, a compression device 9 and a temporary heating device 10 are sequentially arranged on the hot medium pipeline; the inlet of the cold medium pipeline is connected to the reboiling device 8, and the outlet of the cold medium pipeline is connected to the medium inlet of the desorption lean liquid heat exchange device 7; an expansion joint 11 is arranged on the cold medium pipeline.
[0053] The desorption device 2 is as follows Figure 3As shown, a first desorption zone 201, a second desorption zone 202, a second nozzle 203 and a second demister 204 are arranged inside; along the direction from the bottom to the top of the desorption device, the first desorption zone 201 and the second desorption zone 202 are arranged in sequence inside the desorption device 2, the first desorption zone 201 includes at least one first treatment layer, which are the first catalyst layer 2011 and the first filler layer 2012 in sequence, the second desorption zone 202 includes at least one second treatment layer, which are the second catalyst layer 2021 and the second filler layer 2022 in sequence. The rich liquid inlet of the desorption device 2 includes a middle rich liquid inlet and a top rich liquid inlet, the middle rich liquid inlet is located between the first desorption zone 201 and the second desorption zone 202; the top rich liquid inlet is located at the upper part of the second desorption zone 202; a three-way pipeline is arranged between the rich liquid outlet of the lean-rich liquid heat exchange device 6 and the rich liquid inlet of the desorption device 2, and the two outlet ends of the three-way pipeline are respectively connected to the middle rich liquid inlet and the top rich liquid inlet.
[0054] The top gas outlet of the desorption device 2 is connected to the inlet of the reflux device 13 through the condensation device 12; the liquid phase outlet of the reflux device 13 is connected to the top inlet of the desorption device through a reflux pump.
[0055] The lean liquid buffer device 14 is connected to the main pipeline between the mixing device 4 and the cooling device 5 through a side circulation pipeline; the lean liquid buffer device 14 is connected to the filtering device 15 and the purification device 16 in sequence; a lean liquid pump 17 is arranged on the main pipeline; and a liquid return pump 18 is arranged on the side circulation pipeline.
[0056] Example 2
[0057] A method for capturing carbon dioxide comprises the following steps:
[0058] Flue gas to be purified containing CO2 enters the absorption device 1 from the flue gas inlet to be purified, and the absorbent enters the absorption device 1 from the absorbent inlet, and is sprayed through the first nozzle 102. The flue gas to be purified contacts the organic absorbent sprayed from top to bottom in reverse direction, and the CO2 in the flue gas reacts with the absorbent to generate organic salts, which are captured. The flue gas with CO2 removed is washed and defogged and then discharged into the atmosphere or to a designated location from the purified flue gas outlet of the absorption device 1. After the absorbent absorbs CO2, part of it becomes organic salts, and part of it remains in an organic state, becoming rich liquid, which is discharged from the rich liquid outlet of the absorption device 1.
[0059] The rich liquid enters the phase separation device 3 through the rich liquid pump 19 from the discharge port of the self-absorption device 1 for phase separation treatment to obtain a light phase and a heavy phase. The heavy phase obtained from the phase separation device 3 enters the lean-rich liquid heat exchange device 6 through the heavy phase pump 20, and undergoes heat exchange treatment with the desorbed lean liquid from the desorption device 2; after the heavy phase is heated, a portion enters the desorption device 2 from the middle rich liquid inlet through a three-way pipeline for high-temperature desorption treatment to release CO2; a portion enters the top of the desorption device 2 from the top rich liquid inlet, is sprayed through the second spray device, and then uses the waste heat at the top of the desorption device 2 for heating and desorption. This small portion of spraying can reduce the desorption energy consumption to a certain extent.
[0060] After the heavy phase is desorbed in the desorption tower, the generated CO2 gas, water vapor, and organic gas phase substances are discharged from the top of the desorption device 2. After heat exchange through the condensation device 12, the condensed water and organic gas phase substances are recovered to the reflux device 13, and further refluxed to the top of the desorption device 2; the CO2 product gas is discharged to the designated location.
[0061] The material discharged from the bottom of the desorption device 2 is the lean liquid organic absorbent after desorption. The desorption lean liquid is in a gas-liquid two-phase state with a relatively high temperature. It enters the desorption lean liquid heat recovery device and exchanges heat with the medium (water) circulating in the heat pump unit. The heat in the desorption lean liquid is recovered, and the gas phase is completely converted into a liquid phase, while the temperature is reduced. The medium of the heat pump unit is heated and completely converted into a gas through heat exchange with the desorption lean liquid. It is compressed by the compression device 9 to increase the temperature and pressure, and enters the reboiling device 8 to heat the mixed liquid from the bottom of the desorption device 2, thereby providing desorption heat to the desorption device.
[0062] After passing through the reboiling device 8, the medium of the heat pump unit is liquefied into a gas-liquid mixed phase, which is decompressed and expanded into gas through the expansion joint 11, and enters the desorption lean liquid heat recovery device again, where it is heated by the desorption lean liquid to form a cycle. No external heat source is required during normal operation. When the system is debugged and started, if the heat after the medium of the heat pump unit is vaporized and compressed is not enough to provide desorption heat, the temporary heating device 10 can be used to supplement the external heat to increase the heat. The desorption lean liquid after heat exchange in the desorption lean liquid heat recovery device further enters the lean-rich liquid exchange device for heat exchange with the heavy phase.
[0063] The light phase obtained by the phase separation device 3 enters the mixing device 4 and is mixed with the desorbed lean liquid obtained by desorption to obtain a mixed lean liquid. Part of the mixed lean liquid passes through the lean liquid pump 17 and the cooling device 5 in sequence and enters the top of the absorption device 1 to be reused as an adsorbent. Part of the mixed lean liquid can be further processed by the lean liquid buffer device 14, the filtering device 15 and the purification device 16, and then enters the top of the absorption device 1 through the cooling device 5.
[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.
Claims
1. A carbon dioxide capture system, characterized in that: It includes an absorption unit, a desorption unit, a phase separation unit, a lean liquid recycling unit, a heat exchange unit and a heat pump unit; The absorption unit includes an absorption device; the desorption unit includes a desorption device; the phase separation unit includes a phase separation device; the lean liquid recycling unit includes a mixing device and a cooling device; the heat exchange unit includes a lean and rich liquid heat exchange device; the heat pump unit includes a desorption lean liquid heat exchange device and a reboiling device; The rich liquid outlet of the absorption device is connected with the rich liquid inlet of the phase separation device; the light phase outlet of the phase separation device is connected with the lean liquid recovery port of the absorption device through the mixing device and the cooling device; the heavy phase outlet of the phase separation device is connected with the rich liquid inlet of the desorption device through the lean-rich liquid heat exchange device; the desorption lean liquid outlet of the desorption device is connected with the lean liquid inlet of the mixing device through the desorption lean liquid heat exchange device and the lean-rich liquid heat exchange device; the desorption lean liquid heat exchange device is connected with the reboiling device through a heating medium circulation loop; the reboiling device is connected with the desorption device through a gas-liquid phase circulation loop.
2. The carbon dioxide capture system according to claim 1, characterized in that: The absorption device is provided with an absorption filler layer, a first nozzle and a first demister inside, wherein the first nozzle is arranged on the upper part of the absorption filler layer; The absorption device is provided with a flue gas inlet to be purified, an absorbent inlet and a purified flue gas outlet; the absorbent inlet is connected to the first nozzle; the flue gas inlet to be purified is located below the absorption filler layer; the purified flue gas outlet is located at the top of the absorption device; the rich liquid outlet of the absorption device is located at the bottom of the absorption device.
3. The carbon dioxide capture system according to claim 1, characterized in that: The heating medium circulation loop includes a hot medium pipeline and a cold medium pipeline; The inlet of the heat medium pipeline is connected to the medium outlet of the desorption lean liquid heat exchange device, and the outlet of the heat medium pipeline is connected to the medium inlet of the reboiler; along the direction from the inlet to the outlet of the heat medium pipeline, a compression device and a temporary heating device are sequentially arranged on the heat medium pipeline; The inlet of the cold medium pipeline is connected to the reboiler, and the outlet of the cold medium pipeline is connected to the medium inlet of the desorption lean liquid heat exchange device; an expansion joint is arranged on the cold medium pipeline.
4. The carbon dioxide capture system according to claim 1, characterized in that: The desorption unit also includes a condensing device and a reflux device; The top gas outlet of the desorption device is connected to the inlet of the reflux device through the condensing device; the liquid phase outlet of the reflux device is connected to the top inlet of the desorption device through a reflux pump.
5. The carbon dioxide capture system according to claim 1, characterized in that: The desorption device is provided with a first desorption zone, a second desorption zone, a second nozzle and a second demister inside; Along the direction from the bottom to the top of the desorption device, a first desorption zone and a second desorption zone are sequentially arranged inside the desorption device, the first desorption zone includes at least one first treatment layer, which is sequentially a first catalyst layer and a first filler layer, and the second desorption zone includes at least one second treatment layer, which is sequentially a second catalyst layer and a second filler layer.
6. The carbon dioxide capture system according to claim 5, characterized in that: The rich liquid inlet of the desorption device comprises a middle rich liquid inlet and a top rich liquid inlet, wherein the middle rich liquid inlet is located between the first desorption zone and the second desorption zone; and the top rich liquid inlet is located at the upper part of the second desorption zone; The rich liquid outlet of the lean-rich liquid heat exchange device is connected to the middle rich liquid inlet and the top rich liquid inlet through a three-way pipeline.
7. The carbon dioxide capture system according to claim 1, characterized in that: The lean liquid recycling unit also includes a lean liquid buffer device, a filtering device and a purification device; A main pipeline is provided between the mixing device and the cooling device; the lean liquid buffer device is connected to the main pipeline through a side circulation pipeline; The lean liquid buffer device is sequentially connected to the filtering device and the purifying device.
8. The carbon dioxide capture system according to claim 7, characterized in that: A lean liquid pump is provided on the main pipe; A liquid return pump is arranged on the side circulation pipeline.
9. The carbon dioxide capture system according to claim 1, characterized in that: The absorption device and the phase separation device are connected via a rich liquid pump.
10. The carbon dioxide capture system according to claim 1, characterized in that: The heavy phase outlet of the phase separation device is connected to the rich liquid inlet of the lean-rich liquid heat exchange device through a heavy phase pump.