Carbon dioxide trapping method and system and application

Abstract

The invention relates to the technical field of carbon dioxide trapping, and discloses a carbon dioxide trapping method and system and application, and the method comprises the following steps: 1) enabling flue gas containing carbon dioxide to be in contact with water washing liquid to remove dust in the flue gas; 2) contacting the flue gas treated in the step 1) with a carbon dioxide absorbent to form a rich solution; 3) desorbing the rich solution in the step 2) under the supergravity to obtain carbon dioxide and a barren solution; and (4) collecting the heat of the discharged material in the step (3) for the outlet material to realize heat recovery and reutilization. The method has the advantages of low cost and low energy consumption.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and more specifically to a carbon dioxide capture method, system, and application. Background Technology

[0002] Carbon dioxide capture technology has become one of the key research areas globally to address global warming and reduce carbon dioxide emissions into the atmosphere. Future research needs to tackle the challenges and difficulties of these technologies and methods to overcome current bottlenecks and promote the economic viability, efficiency, and scalability of carbon dioxide capture technology.

[0003] Carbon dioxide capture (CO2) technology is a key carbon reduction technology that can effectively reduce CO2 emissions and slow the rate of global warming. In recent years, with increasing global attention to climate change, the research and application of CO2 capture technology have received widespread attention and rapid development. Existing CO2 capture technologies broadly include pre-combustion capture, post-combustion capture, oxy-fuel combustion, and chemical looping combustion. Each technology has its advantages and limitations; currently, no single technology can independently meet the requirements of high efficiency, low cost, low energy consumption, and large-scale operation. Post-combustion capture involves capturing CO2 after fuel combustion. This method has the advantage of capturing CO2 produced during combustion, but it may require higher energy consumption and costs. Common technologies include amine absorption and carbonate absorption.

[0004] In the prior art, CN201510529951.2 discloses a carbon dioxide capture system, including an absorption tower having: a first inlet connected to a fan outlet; a first outlet located at the top of the absorption tower; a second inlet located at the upper part of the absorption tower; and a second outlet located at the bottom of the absorption tower. This technology uses traditional absorption towers, and the maintenance and repair costs of carbon steel + anti-corrosion layer and alloy absorption towers are increasing year by year. CN201910171708.6 discloses a circulating pretreatment system for carbon dioxide capture in coal-fired power plants, including a water washing tower, multiple packing layers arranged from bottom to top inside the water washing tower, a circulating water cooler, an automatic alkali addition device, and a salinity adjustment device. This pretreatment system employs a combination of multiple packing layers to thoroughly remove harmful substances such as dust and SO2 from the flue gas, improving washing efficiency and reducing flue gas temperature. The external washing tower is equipped with an automatic alkali addition device and a salinity adjustment device, which automatically adjusts the alkali dosage based on the pH setting of the circulating washing water to effectively remove acidic substances from the flue gas, ensuring the washing effect. It can also automatically replenish water according to the salinity of the circulating washing water to prevent scaling due to excessive salinity. Flue gas commonly contains nitrogen oxides, sulfur oxides, and dust, and generally requires pretreatment before entering the absorption tower. However, the water washing tower used in this technology suffers from low transfer efficiency and poor mass transfer. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of high capture cost and difficulty in scaling up large-scale carbon capture and absorption towers in the existing technology, and to provide a carbon dioxide capture method, system and application with the advantages of low cost and low energy consumption.

[0006] To achieve the above objectives, the present invention provides a carbon dioxide capture method, the method comprising the following steps:

[0007] 1) Contact the flue gas containing carbon dioxide with a water washing solution to remove dust from the flue gas;

[0008] 2) The flue gas treated in step 1) is contacted with a carbon dioxide absorbent to form a rich liquid;

[0009] 3) Desorb the rich solution from step 2) under hypergravity to obtain carbon dioxide and lean solution;

[0010] 4) The heat collected from the discharge in step 3) is used to achieve heat recovery and reuse of the discharged material.

[0011] A second aspect of the present invention provides a carbon dioxide capture system, the carbon dioxide capture system comprising:

[0012] A pretreatment unit is used to remove dust from flue gas containing carbon dioxide;

[0013] The absorption unit is connected to the gas phase outlet of the pretreatment unit and is used to bring the carbon dioxide absorbent into contact with the flue gas to form a rich liquid.

[0014] The desorption unit is connected to the rich liquid outlet of the absorption unit and is used to desorb carbon dioxide from the rich liquid under hypergravity to obtain a lean liquid.

[0015] A heat exchange unit is used to collect the heat discharged from the desorption unit.

[0016] This invention provides the application of the carbon dioxide capture method and / or carbon dioxide capture system of the present invention in the capture of carbon dioxide of more than 500,000 tons / year.

[0017] Through the above technical solutions, the carbon dioxide capture method of the present invention uses supergravity desorption to break the rich liquid into droplets, liquid lines and liquid films, thereby improving the efficiency of heat and mass utilization; combined with heat collection technology, it can realize the comprehensive utilization of heat and reduce energy consumption; furthermore, the use of concrete absorption towers can improve service life and reduce maintenance probability; in large-scale carbon capture, the cost of carbon dioxide capture can be significantly reduced, and it has the advantages of high efficiency, low cost, low energy consumption and large scale. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of a carbon dioxide capture system according to some embodiments of the present invention;

[0019] Figure 2 These are schematic diagrams of the structure of a cyclone separator according to some embodiments of the present invention;

[0020] Figure 3 These are schematic diagrams of the concrete absorption towers according to some embodiments of the present invention;

[0021] Figure 4 These are schematic diagrams of the supergravity desorption device according to some embodiments of the present invention;

[0022] Figure 5 This is a schematic diagram of the structure of a supergravity desorption device according to other embodiments of the present invention;

[0023] Figure 6 This is a schematic diagram of the structure of a mobile bed according to some embodiments of the present invention.

[0024] Explanation of reference numerals in the attached figures

[0025] 1. Pretreatment unit; 1-1 Tangential flue gas inlet;

[0026] 1-2 Liquid phase feed unit; 1-3 Gas phase outlet;

[0027] 1-4 Liquid phase outlets; 2 Absorption units;

[0028] 2-1 Flue gas inlet; 2-2 Carbon dioxide absorbent / lean liquor inlet;

[0029] 2-3 Exhaust gas outlet; 2-4 Rich liquid outlet;

[0030] 2-5 Packing unit; 3 Desorption unit;

[0031] 3-1-1 Housing; 3-1-2 Rotating shaft;

[0032] 3-1-3 Bearing; 3-1-4 Microwave head;

[0033] 3-1-5 Lateral lean liquid outlet; 3-1-6 Lateral gas inlet;

[0034] 3-1-7 Rich liquid inlet; 3-1-8 Gas outlet;

[0035] 3-2-1 Liquid inlet; 3-2-2 Air inlet;

[0036] 3-2-3 Liquid outlet; 3-2-4 Gas outlet;

[0037] 4. Lean liquor purification unit; 4-1. Mobile stand;

[0038] 4-2 Purification tank; 5 Heat exchange unit. Detailed Implementation

[0039] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0040] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0041] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions. "Inner" and "outer" generally refer to the inner and outer parts of the cavity relative to the chamber or the radial inner and outer parts relative to the center of the circle.

[0042] This invention discloses a carbon dioxide capture method, which includes the following steps:

[0043] 1) Contact the flue gas containing carbon dioxide with a water washing solution to remove dust from the flue gas;

[0044] 2) The flue gas treated in step 1) is contacted with a carbon dioxide absorbent to form a rich liquid;

[0045] 3) Desorb the rich solution from step 2) under hypergravity to obtain carbon dioxide and lean solution;

[0046] 4) Collect and reuse the heat from the output material in step 3).

[0047] The carbon dioxide capture method of the present invention adopts supergravity coupled heat collection technology to realize the comprehensive utilization of heat. Compared with traditional desorption technology, the desorption energy consumption can be reduced by more than 15-20%, and the carbon dioxide capture cost can be significantly reduced in large-scale carbon capture.

[0048] In some embodiments, the flue gas in step 1) is made into a swirling flow, so that the washing liquid is dispersed and in contact with the swirling flue gas. It should be noted that the flue gas from industrial plants, including refinery catalytic cracking units, refinery ammonia synthesis units, refinery hydrogen production units, and coal-fired boilers in power plants, generally contains substances such as nitrogen oxides, sulfur oxides, and dust. The water washing tower method used in the prior art has the defects of low transfer efficiency and poor mass transfer. Especially in large-scale carbon capture, this defect will be amplified. The present invention makes the flue gas into a swirling flow, breaking the washing liquid into liquid films, liquid lines, and liquid droplets, increasing the mass transfer specific surface area, reducing the amount of washing liquid used, and improving the treatment effect.

[0049] The washing solution in this invention has no special requirements. For example, it can be an alkaline solution that can remove sulfur oxides or water. The alkaline solution can be a commonly used sodium hydroxide aqueous solution.

[0050] In this invention, the range of conditions for contact between flue gas and carbon dioxide absorbent is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. For this invention, the conditions for contact between flue gas and carbon dioxide absorbent in step 2) include: temperature range of 40-50°C and normal pressure.

[0051] In this invention, conventional carbon dioxide absorbents are applicable. The following is an illustrative description, but it does not limit the scope of the invention. In some embodiments, the carbon dioxide absorbent is selected from at least one of MDEA, MEA, AEEA, and PZ.

[0052] It should be noted that traditional absorption towers are mostly made of metal, such as carbon steel with anti-corrosion coating and alloy absorption towers. However, the maintenance and repair costs of these absorption towers are increasing year by year, especially when applied to large-scale capture processes, where maintenance and repair costs are even higher. Therefore, in some embodiments, the flue gas and carbon dioxide absorbent in step 2) are contacted in a concrete absorption tower. Compared with the existing absorption towers that are mainly made of metal materials, concrete absorption towers have a lower maintenance and repair probability over a service life of several decades. They have advantages such as fire resistance, durability, low overall cost, and strong design flexibility, resulting in better overall benefits. Under the premise that the absorption towers have the same structure, concrete absorption towers can accommodate more large internal components. More importantly, with the trend of towers becoming larger, concrete absorption towers that are tens or even hundreds of meters high are increasingly showing advantages in saving initial investment. Taking large-scale low-concentration carbon dioxide capture as an example, compared with the existing metal absorption towers, concrete absorption towers can significantly reduce carbon dioxide capture costs. Moreover, concrete towers can be cast in one piece on site using molds, overcoming the construction difficulties of large towers; at the same time, based on anti-corrosion technology, long-term operation of large-scale carbon capture can be achieved.

[0053] To improve the service life of concrete absorption towers, in some embodiments, the inner wall of the concrete absorption tower is treated with existing technology to form an anti-corrosion layer. For example, corrosion-resistant bricks and anti-corrosion adhesives can be used to integrate the wall anti-corrosion and the tower structure through a composite inlay process.

[0054] It should be noted that in the prior art, the desorption of amine-rich liquid is mainly achieved by feeding it into the top of the regeneration tower, where it comes into contact with the hot steam flowing counter-currently from the bottom. The contact state between the gas and liquid cannot be easily controlled inside the regeneration tower, and there is often a defect of insufficient heat transfer. Therefore, this invention adopts centrifugal desorption, which uses centrifugal force to break up the amine-rich liquid and improve the efficiency of heat and mass utilization. In order to reduce desorption energy consumption, in some embodiments, in step 3), the amine-rich liquid is desorbed under microwave and centrifugal conditions. This invention uses a combination of microwave and centrifugal methods to achieve good desorption effect while reducing desorption energy consumption.

[0055] In some embodiments, the microwave frequency is 2450 ± 50 MHz.

[0056] In some embodiments, the hypergravity operating conditions include a rotational speed of 400-1200 rpm.

[0057] In some embodiments, in step 3), hot hydrogen and / or steam can be used to desorb the rich liquid.

[0058] To reduce the latent heat during the desorption process, in some embodiments, hot hydrogen is preferably used to desorb the rich liquid. The hydrogen and carbon dioxide obtained after desorption can be further used to prepare methanol or low-carbon olefins. More preferably, the temperature of the hot hydrogen is 90-108°C.

[0059] In some embodiments, the volumetric flow rate ratio of hot hydrogen to rich liquid is 30-60:1.

[0060] In some embodiments, the lean liquid from step 3) is returned to step 2) to contact the flue gas from step 1) to absorb carbon dioxide. Preferably, the lean liquid from step 3) is purified and then returned to step 2) to contact the flue gas from step 1) to absorb carbon dioxide.

[0061] In this invention, there are no special requirements for continuous purification of lean liquor. Commonly used purifying agents can be used in this invention. The following is an illustrative description, but it does not limit the scope of this invention. In some embodiments, ion exchange resin is used to continuously purify lean liquor.

[0062] In this invention, the range of selectable purification conditions is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. For this invention, the purification conditions include: normal temperature and normal pressure.

[0063] In some embodiments, in step 4), a heat pump is used to collect the heat from the discharge in step 3).

[0064] Based on the foregoing disclosure, this invention discloses a carbon dioxide capture system, such as... Figure 1 As shown, the carbon dioxide capture system includes:

[0065] Pretreatment unit 1 is used to remove dust from flue gas containing carbon dioxide;

[0066] Absorption unit 2 is connected to the gas phase outlet of pretreatment unit 1 and is used to bring carbon dioxide absorbent into contact with flue gas to form a rich liquid.

[0067] Desorption unit 3 is connected to the rich liquid outlet of absorption unit 2 and is used to desorb carbon dioxide from the rich liquid under hypergravity to obtain a lean liquid.

[0068] Heat exchange unit 5 is used to collect the heat discharged from desorption unit 3.

[0069] The carbon dioxide capture system of this invention adopts supergravity coupled heat collection technology to achieve comprehensive utilization of heat. Compared with traditional desorption technology, the desorption energy consumption can be reduced by more than 15-20%, and the carbon dioxide capture cost can be significantly reduced in large-scale carbon capture.

[0070] In some embodiments, the pretreatment unit 1 includes a cyclone separator, such as... Figure 2As shown, the top of the hydrocyclone is provided with a washing liquid feed pipe, and the outlet end of the washing liquid feed pipe is provided with a liquid phase feed element 1-2 that disperses the liquid phase. The hydrocyclone is provided with a cyclone structure that makes the flue gas form a cyclone and contact the washing liquid.

[0071] In this invention, there are no special requirements for the swirling structure, as long as the flue gas can form a swirling flow and come into contact with the washing liquid. In some embodiments, the swirling separator is provided with a cavity with a circular cross-section, and the swirling structure can be set as a tangential flue gas inlet 1-1 opened in the cavity, so that the flue gas forms a swirling flow by tangentially feeding into the cavity.

[0072] In this invention, there are no special requirements for the liquid phase feeders 1-2, as long as they can disperse the washing liquid as much as possible. In some embodiments, the liquid phase feeders can adopt the high-speed rotating titanium metal disk structure in the prior art.

[0073] In some embodiments, the hydrocyclone separator can be installed in the pretreatment tower. The gas phase outlet 1-4 of the hydrocyclone separator is connected to the top of the pretreatment tower, and the liquid phase outlet 1-3 of the hydrocyclone separator can be connected to the liquid phase feed 1-2 through the water washing liquid circulation pipeline to realize the recycling of the water washing liquid.

[0074] In some embodiments, the absorption unit 2 includes a concrete absorption tower, such as... Figure 1 As shown, the concrete absorption tower has, from top to bottom, an exhaust gas outlet 2-3, a carbon dioxide absorbent / lean liquor inlet 2-2, a flue gas inlet 2-1, and a rich liquor outlet 2-4. The flue gas inlet 2-1 connects to the top of the pretreatment tower, allowing the flue gas from pretreatment unit 1 to come into countercurrent contact with the carbon dioxide absorbent. The carbon dioxide absorbent can be fresh or lean liquor. Figure 3 As shown, a wire mesh demister is installed between the exhaust gas outlet 2-3 and the carbon dioxide absorbent / lean liquor inlet 2-2. Multiple packing units 2-5 are spaced apart along the height direction between the carbon dioxide absorbent / lean liquor inlet 2-2 and the flue gas inlet 2-1. Each packing unit 2-5 is provided with an absorbent distributor, a packing layer, and a liquid collector from top to bottom. The packing layer uses regular packing. The feed end of the absorbent distributor in the first packing unit is connected to the carbon dioxide absorbent / lean liquor inlet 2-2. In two adjacent packing units, the liquid collector of the previous unit is connected to the feed end of the absorbent distributor of the next unit. The nozzle of the absorbent distributor in each packing unit is an atomizing nozzle in the prior art. It can be understood that the higher the atomization degree of the atomizing nozzle, the better the initial dispersion efficiency of the carbon dioxide absorbent and / or lean liquor.

[0075] It should be noted that in systems using amine liquid as carbon dioxide absorbent, "desorption" refers to the process where amine molecules react with CO2 to form unstable salts, which decompose upon heating (~100℃). CO2 diffuses from the liquid phase to the gas phase, achieving CO2 separation and solvent regeneration. The thermal decomposition reaction is the reverse of the absorption process. For a mixed amine system consisting of primary, secondary, and tertiary amines, the reaction kinetics are instantaneous and rapid. Therefore, the instantaneous nature of the desorption reaction kinetics determines that the rate of CO2 molecule mass transfer from the liquid phase to the gas phase is the rate-controlling step of the entire desorption reaction-mass transfer coupling process. The supergravity technology in this invention can enhance the mass transfer effect in this type of process, effectively improving the weaknesses of traditional tower equipment, such as low gas-liquid mass transfer efficiency and large reactor volume.

[0076] In some embodiments, the desorption unit 3 includes a hypergravity desorption device, such as... Figure 4 As shown, the supergravity desorption device includes a housing 3-1-1 surrounding a defined desorption chamber. An axially extending rotating shaft 3-1-2 is provided in the desorption chamber. The rotating shaft 3-1-2 is connected to the housing 3-1-1 via a bearing 3-1-3. Microwave heads 3-1-4 are arranged axially at intervals on the rotating shaft 3-1-2. The top of the housing 3-1-1 has a rich liquid inlet 3-1-7, the upper part has a lateral gas inlet 3-1-6, the lower part has a lateral lean liquid outlet 3-1-5, and the bottom has a gas outlet 3-1-8. A motor is installed at the top of the housing 3-1-1. The motor is connected to the rotating shaft via an electric slip ring. A cable groove is provided on the rotating shaft for installing cables. The microwave heads are electrically connected to the electric slip ring via cables. Specifically, the fixed outer ring of the slip ring is connected to an external power source, the sliding inner ring is tightly clamped to the rotating shaft 3-1-2, and the power source of the inner ring is fixed to the rotating shaft 3-1-2 through a wire groove to power the microwave probe. Then, the rich liquid enters from the side rich liquid inlet 3-1-6, and the hot hydrogen enters from the side gas inlet 3-1-6, making the rotating shaft rotate at 400-1500 rpm. In the presence of microwaves, the rich liquid is desorbed, and the resulting lean liquid is discharged from the side lean liquid outlet 3-1-5. The desorbed CO2 is discharged from the gas outlet 3-1-8.

[0077] In this invention, the coupling of microwave and rotating shaft can reduce desorption temperature and desorption energy consumption. Thermal desorption of amine-rich liquid is achieved in the presence of microwave, while accelerating the flow of amine-rich liquid and improving heat and mass transfer efficiency. Compared with traditional steam desorption, it can reduce desorption energy consumption, shorten the process flow, eliminate the need for a reboiler, and reduce process connections with process engineering steam.

[0078] In some embodiments, the hypergravity desorption device of the desorption unit 3 is not limited to Figure 4 As shown, centrifugal dispersion equipment disclosed in CN 116328496 A can also be used, such as... Figure 5As shown, the top of the shell of the centrifugal dispersion device is provided with a liquid inlet 3-2-1 and an air outlet 3-2-4, the bottom of the shell is provided with a liquid outlet 3-2-3, and the side of the shell is provided with an air inlet 3-2-2. When hydrogen is used to desorb the rich liquid, the air inlet 3-2-2 is connected to the hydrogen feed line. When steam is used to desorb the rich liquid, the liquid outlet 3-2-3 of the centrifugal dispersion device is connected to the air inlet 3-2-2, and a reboiler is provided on the connecting pipeline. In this way, the lean liquid is discharged from the liquid outlet 3-2-3 and fed into the reboiler to generate steam, which enters through the air inlet 3-2-2.

[0079] In the chemical amine carbon dioxide capture process, 60-70% of the energy consumption comes from the desorption process when using amine liquid as a carbon dioxide absorbent. Improving the efficiency of the desorption process will effectively reduce the energy consumption and cost of the chemical amine capture process. Therefore, in some embodiments, the heat exchange unit can use a heat pump component in the prior art (such as a York YHAP-C lithium bromide heat pump component) to collect and heat up the material discharged from the gas outlet 3-1-8 or the gas outlet 3-2-4 of the desorption unit 3 to provide heat for the desorption of the desorption unit 3. In this way, the present invention can break the rich liquid into droplets, liquid lines and liquid films through the supergravity technology, improve the heat and mass utilization efficiency, and further reduce the energy consumption in the desorption process by combining the heat pump component. For large-scale carbon capture (greater than 500,000 tons / year), it has the advantage of lower engineering cost.

[0080] In some embodiments, the lean liquid outlet 3-1-5 or the liquid outlet 3-2-3 of the desorption unit 3 is connected to the absorption unit 2 through a lean liquid pipeline, so that the lean liquid obtained after desorption is returned to the absorption unit to contact the flue gas and absorb carbon dioxide.

[0081] In some embodiments, a lean solution purification unit 4 is preferably installed on the lean solution pipeline to remove thermally stable salts from the lean solution.

[0082] In some embodiments, the lean solution purification unit 4 includes a moving bed, which includes at least one bed layer. Each bed layer includes a moving frame 4-1 capable of moving around the center of the moving bed, and a plurality of purification tanks 4-2 are spaced apart along the length of the moving frame. Specifically, as shown... Figure 6 As shown, the moving frame can be circular and rotatable. Six purification tanks 4-2 are installed at intervals along the circumference of the moving frame, so that the lean liquid enters each purification tank in sequence to remove the thermally stable salts in the lean liquid. In this invention, the moving bed can be set with two bed layers stacked along the height direction, and the two bed layers can be alternately used to purify the lean liquid.

[0083] This invention discloses the application of the carbon dioxide capture method and / or the carbon dioxide capture system of this invention in the capture of carbon dioxide exceeding 500,000 tons / year.

[0084] The advantages of the present invention will be illustrated by the following examples, but the invention is not limited thereto. In the following examples, a carbon dioxide detector is used for evaluation and analysis. The capture efficiency is calculated as the ratio of the carbon dioxide concentration at the outlet of the concrete absorption tower to the carbon dioxide concentration at the inlet. The carbon dioxide purity is calculated as the ratio of the carbon dioxide content in the desorbed gas to the total content of the desorbed gas. The concrete in the concrete absorption tower has a strength of C40 and a seismic resistance level of 7.

[0085] Example 1

[0086] This embodiment adopts Figure 1 The carbon dioxide capture system shown includes: a pretreatment unit 1, an absorption unit 2, a desorption unit 3, a lean solution purification unit 4, and a heat exchange unit 5.

[0087] The pretreatment unit 1 includes a cyclone separator, with a washing liquid feed pipe at the top of the cyclone separator. The discharge end of the washing liquid feed pipe is equipped with a high-speed rotating titanium metal disc structure. The cross-section of the cyclone separator is a circular cavity, and the cyclone structure is set as a tangential flue gas inlet 1-1 opened in the cavity.

[0088] The absorption unit 2 includes a concrete absorption tower. The concrete absorption tower has, from top to bottom, a tail gas outlet 2-3, a carbon dioxide absorbent / lean liquor inlet 2-2, a flue gas inlet 2-1, and a rich liquor outlet 2-4. The flue gas inlet 2-1 is connected to the top of the pretreatment tower. A wire mesh demister is installed between the tail gas outlet 2-3 and the carbon dioxide absorbent / lean liquor inlet 2-2. Multiple packing units 2-5 are spaced apart along the height between the carbon dioxide absorbent / lean liquor inlet 2-2 and the flue gas inlet 2-1. Each packing unit 2-5 has, from top to bottom, an absorbent distributor, a packing layer, and a liquid collector. The feed end of the absorbent distributor in the first packing unit is connected to the carbon dioxide absorbent / lean liquor inlet 2-2. In two adjacent packing units, the liquid collector of the previous unit is connected to the feed end of the absorbent distributor of the next unit.

[0089] Desorption unit 3 adopts Figure 5 The centrifugal dispersion device shown has a liquid inlet 3-2-1 and an air outlet 3-2-4 at the top of the shell, a liquid outlet 3-2-3 at the bottom of the shell, and an air inlet 3-2-2 on the side of the shell. The liquid outlet 3-2-3 and the air inlet 3-2-2 are connected and a reboiler is installed on the connecting pipeline.

[0090] The lean liquid purification unit 4 includes a moving bed, which includes two bed layers. Each bed layer includes a circular moving frame 4-1 that can move around the center of the moving bed. Six purification tanks 4-2 are installed at intervals along the circumference of the moving frame. The outlet 3-2-3 of the desorption unit 3 is connected to the carbon dioxide absorbent / lean liquid inlet 2-2 through a lean liquid pipeline, which is connected to the purification tanks 4-2.

[0091] The heat exchange unit 5 includes a York YHAP-C lithium bromide heat pump assembly. The heat input line of the York YHAP-C lithium bromide heat pump assembly is connected to the gas outlet 3-2-4, and the two ends of the heat output line are connected to the liquid outlet 3-2-3 and the liquid inlet 3-2-1, respectively.

[0092] The aforementioned carbon dioxide capture system treats flue gas from a power plant (carbon dioxide volume content 13.5%). The gas is introduced into the tangential flue gas inlet 1-1 to form a vortex, where it comes into contact with a washing liquid fed through a high-speed rotating titanium metal disc structure. The pretreated flue gas is cooled to 45°C and dust particles are removed by water washing. Contact conditions include a temperature of 45°C and atmospheric pressure. The pretreated flue gas then enters the flue gas inlet 2-1 of the concrete absorption tower. A mixed amine aqueous solution (mass concentration of 35% based on amine) enters the concrete absorption tower through the carbon dioxide absorbent / lean liquid inlet 2-2. The amine solution reacts countercurrently with carbon dioxide, achieving a capture efficiency of 98%, forming a rich amine solution which enters the ultragravity desorption unit 3 through the rich liquid outlet 2-4. The desorption unit 3 employs… Figure 5 The centrifugal dispersion device shown is in countercurrent contact with steam (temperature 105°C) from the reboiler. The centrifugal dispersion device rotates at 450 r / min, and the steam to amine-rich liquid feed volume ratio is 50:1. The amine-rich liquid undergoes a desorption reaction (desorption pressure is atmospheric pressure) to become a lean amine liquid. The lean amine liquid passes through a moving bed on the lean liquid pipeline and is desorbed by ion exchange resin under ambient temperature and pressure conditions. After removing thermally stable salts, it is returned to the concrete tower through the carbon dioxide absorbent / lean liquid inlet 2-2. The desorbed carbon dioxide and lean amine liquid exchange heat in the heat pump assembly. In this embodiment, the desorption energy consumption is 2.6 GJ / tCO2, and the purity of the desorbed carbon dioxide reaches 97%.

[0093] Example 2

[0094] Unlike Example 1, the aforementioned carbon dioxide capture system is used to treat flue gas (30% carbon dioxide volume content) from the Daqing Petrochemical catalytic cracking unit. The gas is introduced into the tangential flue gas inlet 1-1 to form a swirling flow, where it comes into contact with a washing liquid fed through a high-speed rotating titanium metal disc structure. The pretreated flue gas is cooled to 45°C and dust particles are removed by water washing. The contact conditions include a temperature of 45°C and atmospheric pressure. Subsequently, the pretreated flue gas enters the flue gas inlet 2-1 of the concrete absorption tower. A mixed amine aqueous solution (35% by mass concentration of amine) enters the concrete absorption tower through the carbon dioxide absorbent / lean liquor inlet 2-2. The amine solution reacts countercurrently with carbon dioxide, achieving a capture efficiency of 95%, forming a rich amine solution which enters the ultragravity desorption unit 3 through the rich liquor outlet 2-4. The desorption unit 3 employs… Figure 5 The centrifugal dispersion device shown is in countercurrent contact with steam (temperature 105°C) from the reboiler. The centrifugal dispersion device rotates at 800 r / min, and the steam to amine-rich liquid feed volume ratio is 35:1. The amine-rich liquid undergoes a desorption reaction (desorption pressure is atmospheric pressure) to become a lean amine liquid. The lean amine liquid passes through a moving bed on the lean liquid pipeline and is desorbed by ion exchange resin under ambient temperature and pressure conditions. After removing thermally stable salts, it is returned to the concrete tower through the carbon dioxide absorbent / lean liquid inlet 2-2. The desorbed carbon dioxide and lean amine liquid exchange heat in the heat pump assembly. In this embodiment, the desorption energy consumption is 2.63 GJ / t CO2, and the purity of the desorbed carbon dioxide reaches 96.5%.

[0095] Example 3

[0096] Unlike Example 1, the aforementioned carbon dioxide capture system is used to treat flue gas (carbon dioxide volume content 18%) from the Daqing Petrochemical catalytic cracking unit. The gas is introduced into the tangential flue gas inlet 1-1 to form a swirling flow, where it comes into contact with a water washing liquid fed through a high-speed rotating titanium metal disc structure. The pretreated flue gas is cooled to 45°C and dust particles are removed by water washing. The contact conditions include a temperature of 45°C and atmospheric pressure. Subsequently, the pretreated flue gas enters the flue gas inlet 2-1 of the concrete absorption tower. A mixed amine aqueous solution (mass concentration of 35% based on amine) enters the concrete absorption tower through the carbon dioxide absorbent / lean liquor inlet 2-2. The amine solution reacts countercurrently with carbon dioxide, achieving a capture efficiency of 97%, forming a rich amine solution which enters the ultragravity desorption unit 3 through the rich liquor outlet 2-4. The desorption unit 3 employs… Figure 5The centrifugal dispersion device shown is in countercurrent contact with steam (temperature 105°C) from the reboiler. The centrifugal dispersion device rotates at 1150 r / min, and the steam to amine-rich liquid feed volume ratio is 60:1. The amine-rich liquid undergoes a desorption reaction (desorption pressure is atmospheric pressure) to become a lean amine liquid. The lean amine liquid passes through a moving bed on the lean liquid pipeline and is desorbed by ion exchange resin under ambient temperature and pressure conditions. After removing thermally stable salts, it is returned to the concrete tower through the carbon dioxide absorbent / lean liquid inlet 2-2. The desorbed carbon dioxide and lean amine liquid exchange heat in the heat pump assembly. In this embodiment, the desorption energy consumption can reach 2.57 GJ / t CO2, and the purity of the desorbed carbon dioxide reaches 97.3%.

[0097] Example 4

[0098] Unlike Example 1, the desorption unit 3 adopts... Figure 4 The illustrated supergravity desorption device includes a housing 3-1-1 surrounding a defined desorption chamber. An axially extending rotating shaft 3-1-2 is provided within the desorption chamber. The rotating shaft 3-1-2 is connected to the housing 3-1-1 via a bearing 3-1-3. Microwave heads 3-1-4 are arranged axially at intervals on the rotating shaft 3-1-2. The housing 3-1-1 has a rich liquid inlet 3-1-7 at its top, a lateral gas inlet 3-1-6 at its upper part, a lateral lean liquid outlet 3-1-5 at its lower part, and a gas outlet 3-1-8 at its bottom. A motor is mounted at the top of the housing 3-1-1 and is connected to the rotating shaft via an electric slip ring. A cable groove is provided on the rotating shaft for mounting cables, which electrically connect the microwave heads to the electric slip ring. The rich liquid inlet 3-1-7 of the supergravity desorption device is connected to the rich liquid outlet 2-4. Hot hydrogen is introduced into the side gas inlet 3-1-6 of the supergravity desorption device. The lean liquid outlet 3-1-5 is connected to the carbon dioxide absorbent / lean liquid inlet 2-2 through a lean liquid pipeline. The lean liquid pipeline is connected to the purification tank 4-2. The heat exchange unit 5 includes a York YHAP-C lithium bromide heat pump assembly. The heat input pipeline of the York YHAP-C lithium bromide heat pump assembly is connected to the gas outlet 3-1-8. The two ends of the heat output pipeline are connected to the desorption chamber.

[0099] Among them, the rotating shaft 3-1-2 rotates at 800 rpm, the microwave head 3-1-4 has a frequency of 2450 MHz, and the volume flow ratio of hot hydrogen gas (temperature 95℃) entering through the side gas inlet 3-1-6 to rich amine liquid entering through the rich liquid inlet 3-1-7 is 50:1.

[0100] Results: Compared with Example 1, the desorption temperature decreased by 10°C, the latent heat of vaporization decreased by 10%, the desorption energy consumption reached 1.9 GJ / t CO2, and the purity of desorbed carbon dioxide reached 98.7%.

[0101] Example 5

[0102] Unlike Example 1, the desorption unit 3 adopts... Figure 4 The illustrated supergravity desorption device includes a housing 3-1-1 surrounding a defined desorption chamber. An axially extending rotating shaft 3-1-2 is provided within the desorption chamber. The rotating shaft 3-1-2 is connected to the housing 3-1-1 via a bearing 3-1-3. Microwave heads 3-1-4 are arranged axially at intervals on the rotating shaft 3-1-2. The housing 3-1-1 has a rich liquid inlet 3-1-7 at its top, a lateral gas inlet 3-1-6 at its upper part, a lateral lean liquid outlet 3-1-5 at its lower part, and a gas outlet 3-1-8 at its bottom. A motor is mounted at the top of the housing 3-1-1 and is connected to the rotating shaft via an electric slip ring. A cable groove is provided on the rotating shaft for mounting cables, which electrically connect the microwave heads to the electric slip ring. The rich liquid inlet 3-1-7 of the supergravity desorption device is connected to the rich liquid outlet 2-4. Hot hydrogen is introduced into the side gas inlet 3-1-6 of the supergravity desorption device. The lean liquid outlet 3-1-5 is connected to the carbon dioxide absorbent / lean liquid inlet 2-2 through a lean liquid pipeline. The lean liquid pipeline is connected to the purification tank 4-2. The heat exchange unit 5 includes a York YHAP-C lithium bromide heat pump assembly. The heat input pipeline of the York YHAP-C lithium bromide heat pump assembly is connected to the gas outlet 3-1-8. The two ends of the heat output pipeline are connected to the desorption chamber.

[0103] Without starting the microwave, the rotation speed of the shaft 3-1-2 is 800 rpm, and the volume flow ratio of the hot hydrogen gas (temperature 105℃) entering through the side gas inlet 3-1-6 to the rich amine liquid entering through the rich liquid inlet 3-1-7 is 50:1.

[0104] Results: Compared with Example 1, the desorption temperature remained unchanged, the latent heat of vaporization decreased by 10%, the desorption energy consumption reached 2.3 GJ / tCO2, and the purity of carbon dioxide after desorption reached 98.2%.

[0105] Example 6

[0106] Unlike Example 1, for the carbon dioxide capture system treating flue gas (carbon dioxide volume content 12%) from the Daqing Petrochemical catalytic cracking unit, the desorption unit 3 does not have a reboiler. The centrifugal dispersion equipment is connected to hot hydrogen from the process engineering pipeline network and comes into countercurrent contact with the rich amine liquid. The feed volume flow ratio of hydrogen to rich amine liquid is 45:1.

[0107] Results: Compared with Example 1, the desorption temperature remained unchanged, the latent heat of vaporization decreased by 12%, the desorption energy consumption reached 2.2 GJ / tCO2, and the purity of carbon dioxide after desorption reached 98.0%.

[0108] Example 7

[0109] Unlike Example 1, the desorption unit 3 adopts... Figure 4The illustrated supergravity desorption device includes a housing 3-1-1 surrounding a defined desorption chamber. An axially extending rotating shaft 3-1-2 is provided within the desorption chamber. The rotating shaft 3-1-2 is connected to the housing 3-1-1 via a bearing 3-1-3. Microwave heads 3-1-4 are arranged axially at intervals on the rotating shaft 3-1-2. The housing 3-1-1 has a rich liquid inlet 3-1-7 at its top, a lateral gas inlet 3-1-6 at its upper part, a lateral lean liquid outlet 3-1-5 at its lower part, and a gas outlet 3-1-8 at its bottom. A motor is mounted at the top of the housing 3-1-1 and is connected to the rotating shaft via an electric slip ring. A cable groove is provided on the rotating shaft for mounting cables, which electrically connect the microwave heads to the electric slip ring. The rich liquid inlet 3-1-7 of the supergravity desorption device is connected to the rich liquid outlet 2-4. Steam is introduced into the lateral gas inlet 3-1-6 of the supergravity desorption device. The lean liquid outlet 3-1-5 is connected to the carbon dioxide absorbent / lean liquid inlet 2-2 through a lean liquid pipeline. The lean liquid pipeline is connected to the purification tank 4-2. The heat exchange unit 5 includes a York YHAP-C lithium bromide heat pump assembly. The heat input pipeline of the York YHAP-C lithium bromide heat pump assembly is connected to the gas outlet 3-1-8. The two ends of the heat output pipeline are connected to the desorption chamber.

[0110] Among them, the rotating shaft 3-1-2 rotates at 800 rpm, the microwave head 3-1-4 has a frequency of 2450 MHz, and the volume flow ratio of the steam (temperature 95℃) entering through the side gas inlet 3-1-6 to the rich amine liquid entering through the rich liquid inlet 3-1-7 is 50:1.

[0111] Results: Compared with Example 1, the desorption temperature remained unchanged, the latent heat of vaporization decreased by 2%, the desorption energy consumption reached 2.43 GJ / tCO2, and the purity of carbon dioxide after desorption reached 98.3%.

[0112] Comparative Example 1

[0113] Unlike Example 1, the desorption unit uses a regeneration tower with the same processing capacity as in the prior art for desorption.

[0114] Result: Desorption energy consumption reached 2.8 GJ / t CO2.

[0115] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for capturing carbon dioxide, characterized in that, The method includes the following steps: 1) Contact the flue gas containing carbon dioxide with a water washing solution to remove dust from the flue gas; 2) The flue gas treated in step 1) is contacted with a carbon dioxide absorbent to form a rich liquid; 3) Desorb the rich solution from step 2) under hypergravity to obtain carbon dioxide and lean solution; 4) Collect the heat from the discharge in step 3).

2. The method according to claim 1, characterized in that, In step 1), the flue gas forms a swirling flow, allowing the washing liquid to disperse and contact the swirling flue gas; and / or The volumetric content of carbon dioxide in flue gas is 10-30%.

3. The method according to claim 1 or 2, characterized in that, In step 2), the flue gas comes into contact with the carbon dioxide absorbent in a concrete absorption tower, the inner wall of which is provided with an anti-corrosion layer.

4. The method according to claim 1, characterized in that, In step 4), a heat pump is used to collect the heat from the discharged material.

5. The method according to claim 1, characterized in that, In step 3), the rich liquid is desorbed under microwave and hypergravity conditions; Preferably, The frequency of the microwave is 2450 ± 50 MHz; and / or The hypergravity operating conditions include a rotational speed of 400-1200 rpm.

6. The method according to claim 1 or 5, characterized in that, In step 3), hot hydrogen and / or steam are used as a gas source to desorb the rich liquid; Preferably, Hot hydrogen is used as a gas source for desorption of the rich liquid, preferably at a temperature of 90-108°C; and / or The volumetric flow rate ratio of the hot hydrogen to the rich liquid is 30-60:

1.

7. The method according to claim 1, characterized in that, The method further includes: returning the lean solution from step 3) to step 2) or purifying the lean solution from step 3) and returning it to step 2); It is preferable to use ion exchange resin to continuously purify the lean solution.

8. A carbon dioxide capture system, characterized in that, The carbon dioxide capture system includes: Pretreatment unit (1) is used to remove dust from flue gas containing carbon dioxide; The absorption unit (2) is connected to the gas phase outlet of the pretreatment unit (1) and is used to make the carbon dioxide absorbent come into contact with the flue gas to form a rich liquid. The desorption unit (3) is connected to the rich liquid outlet of the absorption unit (2) and is used to desorb carbon dioxide from the rich liquid under hypergravity to obtain a lean liquid. The heat exchange unit (5) is used to collect the heat discharged from the desorption unit (3).

9. The carbon dioxide capture system according to claim 8, characterized in that, The pretreatment unit (1) includes a cyclone separator, which has a liquid phase feeder (1-2) that makes the washing liquid a mist distribution and a cyclone structure that makes the flue gas form a cyclone and contact the washing liquid. Preferably, the cyclone separator has a cavity with a circular cross-section, and the cyclone structure is configured as a tangential flue gas inlet (1-1) opened in the cavity.

10. The carbon dioxide capture system according to claim 8 or 9, characterized in that, The absorption unit (2) includes a concrete absorption tower, the inner wall of which is provided with an anti-corrosion layer; Preferably, the concrete absorption tower is provided with multiple packing units (2-5) spaced apart along the height direction, and each packing unit (2-5) is provided with an absorbent distributor, a packing layer and a liquid collector in sequence from top to bottom.

11. The carbon dioxide capture system according to claim 8, characterized in that, The desorption unit (3) includes a supergravity desorption device, which includes a housing (3-1-1) surrounding a defined desorption chamber. The desorption chamber is provided with an axially extending rotating shaft (3-1-2). The rotating shaft (3-1-2) is connected to the housing (3-1-1) through a bearing (3-1-3). The rotating shaft (3-1-2) is provided with microwave heads (3-1-4) arranged axially at intervals. The top of the housing (3-1-1) is provided with a rich liquid inlet (3-1-7), the upper part is provided with a lateral gas inlet (3-1-6), the lower part is provided with a lateral lean liquid outlet (3-1-5), and the bottom is provided with a gas outlet (3-1-8).

12. The carbon dioxide capture system according to claim 8 or 11, characterized in that, The lean liquid outlet of the desorption unit (3) is connected to the absorption unit (2) through a lean liquid pipeline; Preferably, a lean solution purification unit (4) is installed on the lean solution pipeline to remove thermally stable salts from the lean solution.

13. The carbon dioxide capture system according to claim 12, characterized in that, The lean solution purification unit (4) includes a moving bed, which includes at least one bed layer, each bed layer including a moving frame (4-1) capable of moving around the center of the moving bed, and a plurality of purification tanks (4-2) are installed at intervals along the length of the moving frame.

14. The application of the carbon dioxide capture method according to any one of claims 1-7 and / or the carbon dioxide capture system according to any one of claims 8-13 in the capture of carbon dioxide of more than 500,000 tons / year.

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