A flue gas carbon dioxide capture process system

Abstract

The present application provides a kind of flue gas carbon dioxide capture process system, the system includes absorption tower, desorption tower and reboiling tower, the inside of reboiling tower has flue gas heat exchange pipe, the flue gas inlet of the flue gas heat exchange pipe communicates the flue gas pipeline of the system, to convert the heat of the flue gas into the heat required for the desorption of the rich liquid of the desorption tower to generate carbon dioxide gas;Compared with the prior art using steam as the heat source of reboiling tower, the reboiling tower in the present application uses the heat carried by the flue gas of the system itself as the heat source to heat the desorption tower, realizes the desorption of rich liquid to produce carbon dioxide gas, that is, fully utilize the flue gas waste heat (including sensible heat and latent heat) of the system, without steam, the carbon dioxide gas in the absorption liquid can be fully desorbed, reduce the energy consumption of the system, and further reduce the use cost of the system, especially suitable for high-humidity flue gas after low-temperature denitrification in steel industry and waste incineration industry.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and in particular to a flue gas carbon dioxide capture process system. Background Technology

[0002] In recent years, CO2 greenhouse gas emission reduction pathways and CO2 capture and separation technologies from industrial sectors such as power generation, metal smelting, cement production, and chemical synthesis have become research hotspots both domestically and internationally. Organic amine absorption carbon capture technology, due to its advantages of high capture efficiency and mature, stable technology, has become the most widely researched and applied CO2 capture technology.

[0003] The commonly used organic amine absorption method for carbon dioxide capture is as follows: Figure 1 As shown, Figure 1 This is a schematic diagram of the existing organic amine absorption method for carbon dioxide capture. Flue gas from industrial sources, after dust removal, desulfurization, and denitrification, is cooled in pretreatment tower 1' and enters absorption tower 2' at approximately 40°C, where it contacts the absorbent. Carbon dioxide in the flue gas is absorbed by the absorbent, forming a rich solution that exits from the bottom of absorption tower 2', while the decarbonized flue gas exits from the top. The rich solution is heated by a rich solution pump and then transported to the top of the packing in regeneration tower 3'. The rich solution is regenerated at 120-140°C and approximately 200 kPa, desorbing carbon dioxide gas. The regeneration process in the regeneration tower consumes heat energy, which is provided by reboiling tower 12'. The regeneration gas is cooled in condenser 10', and the condensate separated in reflux tank 11' is returned to regeneration tower 3' via a condensate pipeline. The separated carbon dioxide is discharged through a carbon dioxide emission pipeline on reflux tank 11'. After regeneration, the lean solution is discharged from the bottom of the desorption tower 3' and returned to the absorption tower 2' for recycling after cooling.

[0004] The shortcomings of traditional flue gas carbon dioxide capture technology are: ① The heat source of the reboiler is a steam source and the heat source is singular. In order to ensure that CO2 in the absorbent is fully desorbed, a large amount of steam heat source needs to be provided, resulting in high overall energy consumption; ② All CO2 needs to be regenerated by relying on a single steam heat source, the load on the absorber is large, resulting in a large design scale of the absorber and high investment cost.

[0005] How to effectively solve at least one of the above-mentioned defects is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a flue gas carbon dioxide capture process system with low system energy consumption and low operating cost.

[0007] This invention provides a flue gas carbon dioxide capture process system, comprising the following components;

[0008] An absorption tower has a flue gas inlet, a flue gas outlet, and a rich liquid outlet. The absorption tower is used to absorb part of the carbon dioxide in the flue gas to form a rich liquid.

[0009] A desorption tower, the rich liquid inlet of which is connected to the rich liquid outlet of the absorption tower, is used to desorb the rich liquid to generate carbon dioxide gas;

[0010] The reboiling tower has a flue gas heat exchange tube inside, and the flue gas inlet of the flue gas heat exchange tube is connected to the flue gas pipeline of the system to convert part of the heat of the flue gas into the heat required for the rich liquid in the desorption tower to desorb carbon dioxide gas.

[0011] Compared with existing technologies that use steam as the heat source for reboiling towers, the reboiling tower in this invention uses the heat (partial sensible heat and latent heat) carried by the flue gas of the system itself as the heat source to heat the desorption tower, realizing the production of carbon dioxide gas through rich liquid desorption. That is, it makes full use of the waste heat of the system flue gas to complete the full desorption of carbon dioxide gas in the absorbent without steam, reducing system energy consumption and thus reducing system operating costs. It is particularly suitable for high-moisture flue gas after low-temperature denitrification in the steel industry and waste incineration industry.

[0012] Optionally, the flue gas outlet of the flue gas heat exchange tube of the reboiler tower can be connected to the flue gas inlet of the absorption tower, and an adjustment component is also provided on the connecting pipe between the two for adjusting the parameters of the flue gas entering the absorption tower to predetermined operating parameters, the parameters including at least one of temperature and pressure.

[0013] Optionally, the regulating component includes at least one flue gas cooler, and each of the flue gas coolers is connected in series, in parallel, or in series and in parallel on the connecting pipe between the flue gas outlet of the reboiler and the flue gas inlet of the absorption tower.

[0014] Optionally, a flue gas-rich liquid heat exchanger is installed on the connecting pipeline between the rich liquid outlet of the absorption tower and the rich liquid inlet of the desorption tower. The flue gas-rich liquid heat exchanger is used to exchange heat between the flue gas and the rich liquid flowing through it, so as to preheat the rich liquid.

[0015] Optionally, the absorption tower has at least two stages of absorbent packing layers between the flue gas inlet and the flue gas outlet, with each absorbent packing layer arranged at intervals, and also includes an interstage cooler for cooling the absorbent liquid located between the two absorbent packing layers.

[0016] Optionally, the interstage cooler is located outside the absorption tower, and an absorbent outlet and an interstage absorbent inlet are provided between adjacent absorbent packing layers of the absorption tower. The two ends of the heat exchange channel inside the interstage cooler are respectively connected to the absorbent outlet and the interstage absorbent inlet.

[0017] Optionally, the flue gas coolers are connected in series along the flue gas flow direction, and each flue gas cooler is defined as a first-stage flue gas cooler to a M-stage flue gas cooler.

[0018] It also includes a lean liquor cooler for cooling the lean liquor flowing out of the desorption tower;

[0019] It also includes a gas cooler for cooling the carbon dioxide gas flowing out of the desorption tower;

[0020] The cooling medium after heat exchange between the interstage cooler, the M-stage flue gas cooler, the gas cooler, and the lean liquid cooler flows into the first-stage flue gas cooler.

[0021] Optionally, the desorption tower includes an N-stage desorption packing layer and at least one-stage catalytic packing layer. The desorption packing layer provides sufficient contact surface for the gas and liquid phases and creates conditions to improve their turbulence (mainly in the gas phase), thereby facilitating the CO2 desorption mass and heat transfer process and improving desorption efficiency. The catalytic packing layer reduces the energy required for CO2 desorption, lowers the desorption temperature, promotes desorption efficiency, and reduces regeneration energy consumption. The N-stage desorption packing layers are arranged at intervals along the height of the desorption tower. The catalytic packing layer is located below all the desorption packing layers. The desorption tower also has a jet outlet located below the catalytic packing layer, which is connected to the gas outlet pipeline of the desorption tower.

[0022] Optionally, the catalyst packing layer includes at least two levels, each of the catalyst packing layers being arranged at intervals along the height direction, and each level of the catalyst packing layer having a jet nozzle below it.

[0023] Optionally, the desorption tower includes a first connection port and a second connection port, which are respectively connected to the two ends of the liquid inlet heat exchange tube of the reboiler. The first connection port is located below the bottommost catalytic packing layer, and the second connection port is located between the topmost catalytic packing layer and the bottommost desorption packing layer.

[0024] Optionally, it also includes a gas-liquid separator, which is installed in the gas outlet pipeline of the desorption tower, and the liquid medium outlet of the gas-liquid separator is connected to the inner cavity of the absorption tower where the absorbent is provided.

[0025] Optionally, it also includes a rich-lean liquid heat exchanger for exchanging heat between the rich liquid flowing out of the absorption tower and the lean liquid flowing out of the desorption tower;

[0026] Alternatively / and, a rich liquid pump is also provided on the connecting pipeline between the rich liquid outlet of the absorption tower and the rich liquid inlet of the desorption tower.

[0027] Alternatively / and, a lean liquid pump is also provided on the connecting pipeline between the lean liquid outlet of the desorption tower and the lean liquid return port of the absorption tower. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the existing organic amine absorption method for carbon dioxide capture.

[0029] Figure 2 This is a schematic diagram of a specific embodiment of the flue gas carbon dioxide capture process system of the present invention.

[0030] Figures 1 to 2 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0031] Pretreatment tower 1', absorption tower 2', regeneration tower 3', lean and rich liquid heat exchanger 7', reboiling tower 12', condenser 10', reflux tank 11';

[0032] Absorber 1, 1-1 Absorber layer, Desorption tower 2, 2-1 Desorption packing layer, 2-2 Catalytic packing layer, 2-3 Nozzle, Reboiler 3, First-stage flue gas heat exchanger 4, Second-stage flue gas cooler 5, Rich liquid pump 6, Lean-rich liquid heat exchanger 7, Flue gas-rich liquid heat exchanger 8, Lean liquid cooler 9, Interstage cooler 10, Gas cooler 11, Gas-liquid separator 12, Lean liquid pump 13. Detailed Implementation

[0033] In response to the technical problem mentioned in the background technology that "the use of steam energy is relatively energy-intensive and has high operating costs", this paper has conducted extensive research and found that the current flue gas carbon dioxide capture process ignores the actual conditions of the operating environment and simply uses steam as the energy source for the reboiling tower, resulting in high regeneration energy consumption and high operating costs.

[0034] Based on the above research findings, this invention proposes a low-energy-consumption flue gas carbon dioxide capture process system.

[0035] The terms "first" and "second" used in this article are used only for the convenience of describing two or more structures or components that are identical or similar in structure and / or function, and do not indicate any special limitation on order and / or importance.

[0036] The features and exemplary embodiments of various aspects of this application will now be described in detail. In order to make the purpose, technical solution and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a specific embodiment of the flue gas carbon dioxide capture process system of the present invention.

[0038] This invention provides a flue gas carbon dioxide capture process system, comprising an absorption tower 1, a desorption tower 2, and a reboiling tower. This process system is particularly suitable for high-humidity flue gas with a flue gas temperature of 130℃~180℃, a moisture content of 10%~30%, and a high latent heat of vaporization. It is especially suitable for flue gas from the steel industry and waste incineration industry after medium- and low-temperature SCR flue gas denitrification.

[0039] The absorption tower 1 has at least a flue gas inlet, a flue gas outlet, and a rich liquid outlet. The flue gas inlet is usually located at the bottom of the absorption tower 1, and the flue gas outlet is located at the top of the absorption tower 1. There are at least two stages of absorbent packing layers 1-1 between the flue gas inlet and the flue gas outlet of the absorption tower 1, and the absorbent packing layers 1-1 are arranged at intervals. The absorption tower 1 is used to absorb part of the carbon dioxide in the flue gas to form a rich liquid. Specifically, during the process of the flue gas flowing from the flue gas inlet to the flue gas outlet, it can contact the absorbent in the absorbent packing layer and be absorbed by the absorbent to form a rich liquid. The rich liquid can flow out from the rich liquid outlet provided at the bottom of the absorption tower 1, while the decarbonized flue gas flows out from the flue gas outlet at the top of the absorption tower 1.

[0040] The desorption tower 2 of this invention has a rich liquid inlet, a lean liquid outlet, a first connection port, a second connection port, and a gas outlet. The rich liquid inlet of the desorption tower 2 is connected to the rich liquid outlet of the absorption tower 1, and the rich liquid can be desorbed inside the desorption tower 2 to generate carbon dioxide gas. Specifically, the desorption tower 2 is equipped with desorption packing. The main function of the desorption packing is to provide sufficient contact surface for the gas and liquid phases and create conditions to improve their turbulence (mainly the gas phase), thereby facilitating the CO2 desorption mass transfer and heat transfer process and improving the desorption efficiency. The rich liquid inlet and gas outlet are usually located at the top of the desorption tower 2, the lean liquid outlet is located at the bottom of the desorption tower 2, and the first and second connection ports are located below the bottom desorption packing and are respectively connected to the heat exchange pipes of the reboiler. The rich liquid flowing into the desorption tower 2 from the rich liquid inlet is desorbed to produce carbon dioxide gas, and the desorbed lean liquid flows to the bottom of the desorption tower 2. Part of the lean liquid can return to the absorption tower 1 from the lean liquid outlet.

[0041] The reboiling tower in this invention has a flue gas heat exchange tube inside. The flue gas inlet of the flue gas heat exchange tube is connected to the flue gas pipeline of the system, so as to convert part of the sensible heat and a large amount of latent heat of the flue gas into the heat required for the rich liquid in the desorption tower 2 to desorb carbon dioxide gas. In a specific example, the reboiling tower has a flue gas heat exchange tube inside, and the external flue gas indirectly transfers part of its sensible heat and a large amount of latent heat to the interior of the desorption tower 2 by exchanging heat with the absorbent as it flows through the flue gas heat exchange tube.

[0042] Compared with the existing technology that uses steam as the heat source for reboiling towers, the reboiling tower in this invention uses the latent heat and sensible heat carried by the flue gas of the system itself as the heat source to heat the desorption tower 2, so as to realize the production of carbon dioxide gas by rich liquid desorption. That is, it makes full use of the waste heat of the flue gas of the system to complete the full desorption of carbon dioxide gas in the absorbent without steam, reducing system energy consumption and thus reducing system operating costs. It is particularly suitable for the steel industry and the waste incineration industry after low-temperature denitrification of high moisture content flue gas with high latent heat of vaporization.

[0043] In one specific example, the flue gas outlet of the reboiler's flue gas heat exchange tube is connected to the flue gas inlet of the absorber 1, and a regulating component is installed on the connecting pipe between the two. The regulating component is used to adjust the parameters of the flue gas entering the absorber 1 to predetermined operating parameters, including at least one of temperature and pressure. The regulating component can be a temperature regulating component, a pressure regulating component, or a component that can regulate both temperature and pressure.

[0044] In the above embodiments, the flue gas after heat exchange in the reboiler is adjusted by the regulating component to meet the parameters for entering the absorption tower 1, so as to perform decarbonization treatment on the flue gas.

[0045] In this invention, the regulating component includes at least one flue gas cooler. At least one flue gas cooler is connected in series, parallel, or series-parallel on the connecting pipe between the flue gas outlet of the reboiler and the flue gas inlet of the absorption tower 1. Each flue gas cooler is used to cool the flue gas flowing through it. Figure 2 The connecting pipe between the flue gas cooler and the flue gas outlet of the reboiler tower and the flue gas inlet of the absorption tower 1 is shown. Along the flue gas flow direction, each flue gas cooler is defined as the first-stage flue gas cooler 4 to the Mth-stage flue gas cooler.

[0046] Of course, the connection methods for each flue gas cooler are not limited to those listed below. Figure 2 As shown, it can also be arranged in parallel or series-parallel configurations.

[0047] In this embodiment, the cooling medium cools the flue gas flowing through the flue gas cooler, thereby regulating its temperature and pressure. The number of flue gas coolers and the temperature of the cooling medium can be rationally selected based on the actual application environment. Using flue gas coolers to regulate the flue gas temperature fully utilizes the cooling effect, and adjusting flue gas parameters is relatively simple and quick.

[0048] In one specific embodiment, a rich liquid pump 6, a rich liquid-lean liquid heat exchanger, and a flue gas-rich liquid heat exchanger 8 are installed on the connecting pipeline between the rich liquid outlet of the absorption tower 1 and the rich liquid inlet of the desorption tower 2. The rich liquid pump 6 mainly provides the flow power for the rich liquid. The rich liquid-lean liquid heat exchanger is mainly used for heat exchange between the rich liquid flowing out of the absorption tower 1 and the lean liquid flowing out of the desorption tower 2. During this process, the high-temperature lean liquid releases heat and its temperature decreases, while the rich liquid absorbs heat and its temperature increases. The flue gas-rich liquid heat exchanger 8 is used to exchange heat between the flue gas and the rich liquid flowing through it, thereby preheating the rich liquid. The rich liquid-lean liquid heat exchanger is located upstream of the flue gas-rich liquid heat exchanger 8, that is, the flue gas-rich liquid heat exchanger 8 is closer to the desorption tower 2. In other words, after the rich liquid flowing out of the absorption tower 1 absorbs heat from the lean liquid, it is further heated by the flue gas.

[0049] In this embodiment, the raw flue gas with a high moisture content (130℃~180℃, 10%~30% moisture content) can be passed into the flue gas-rich liquid heat exchanger 8 as the heat source required for system regeneration. Within the heat exchanger 8, the high-temperature, high-humidity raw flue gas exchanges heat fully with the relatively lower-temperature rich liquid, thus fully utilizing part of the sensible heat of the flue gas and the large amount of latent heat of the water vapor in the flue gas, replacing the use of more expensive steam and significantly reducing system operating costs. Furthermore, installing the flue gas-rich liquid heat exchanger 8 upstream of the desorption tower 2 can effectively increase the temperature of the rich liquid entering the desorption tower 2, achieving pre-desorption of the rich liquid, thereby reducing the load on the catalytic desorption tower 2 to a certain extent and achieving energy-saving effects.

[0050] In addition, the rich-lean heat exchanger can recover and utilize the heat from the lean liquid, further reducing the system operating cost.

[0051] The flue gas carbon dioxide capture process system of this invention also includes an interstage cooler 10 for cooling all the absorbent liquid flowing through the two absorbent packing layers. Figure 2 As shown, the absorption tower 1 is equipped with three stages of absorption packing layers, from bottom to top: a first absorption packing layer, a second absorption packing layer, and a third absorption packing layer. The space between the first and second absorption packing layers forms a circulation loop with the interstage cooler 10. In this way, after the absorbent passes through the first absorption packing layer, it is cooled by the interstage cooler 10 before returning to the second absorption packing layer. This cooling effect increases the solubility of CO2 in the absorbent, significantly improving the absorption efficiency of the absorbent for capturing carbon dioxide and other gases from the flue gas.

[0052] Of course, the number and location of the interstage coolers 10 are not limited to those described herein. For example, the interstage coolers 10 can also form a circulation loop with the space between the second absorber packing layer and the third absorber packing layer.

[0053] Specifically, the interstage cooler 10 can be located outside the absorption tower 1. This allows for improvements to the existing absorption tower 1 without significantly altering its internal structure. Furthermore, the external location of the interstage cooler 10 provides greater flexibility in its arrangement. Interstage absorbent outlets and inlets are provided between adjacent absorbent packing layers in the absorption tower 1. The two ends of the heat exchange channel inside the interstage cooler 10 are connected to the absorbent outlet and the interstage absorbent inlet, respectively.

[0054] In the above embodiments, the system further includes a lean liquid cooler 9 for cooling the lean liquid flowing out of the desorption tower 2; the outlets of the cooling media of the interstage cooler 10 and the lean liquid cooler 9 are both connected to the cooling media inlet of the first-stage flue gas cooler 4. A gas cooler 11 is also provided at the gas outlet of the desorption tower 2 for cooling the gas medium flowing out of the desorption tower 2. The interstage cooler 10, the second to M stage coolers, the gas cooler 11, and the lean liquid cooler 9 can be connected in parallel to the cooling media pipeline, and the cooling media after heat exchange between the three can converge and flow into the first-stage flue gas cooler 4 to cool the flue gas.

[0055] By utilizing cooling water in multiple stages, the cooling potential of the cooling water can be fully utilized. At the same time, through the multi-stage cooling and temperature reduction of flue gas, the amount of cooling water used can be reduced to the greatest extent, thereby reducing the energy consumption of power equipment and achieving energy saving and consumption reduction in the system.

[0056] In one specific example, the interior of the desorption tower 2 includes an N-stage desorption packing layer 2-1 and at least one-stage catalytic packing layer 2-2. The desorption packing layer 2-1 provides sufficient contact surface for the gas and liquid phases and creates conditions to improve their turbulence (mainly in the gas phase), thereby facilitating the CO2 desorption mass and heat transfer process and improving desorption efficiency. The catalytic packing layer 2-2 reduces the energy required for the CO2 desorption reaction, lowers the desorption temperature, promotes the desorption reaction rate, improves desorption efficiency, and reduces regeneration energy consumption. The N-stage desorption packing layers 2-1 are arranged at intervals along the height direction of the desorption tower 2. The catalytic packing layer 2-2 is located below all the desorption packing layers 2-1. The interior of the desorption tower 2 is also provided with a jet outlet located below the catalytic packing layer 2-2, which is connected to the gas outlet pipeline of the desorption tower 2.

[0057] Specifically, the jet nozzle can be located on the nozzle, and several nozzles can be arranged to form a nozzle layer on the same plane. Each catalytic packing layer 2-2 corresponds to a nozzle layer below it.

[0058] The desorption tower 2 integrates coupled catalysis, desorption, and product gas purging for efficiency enhancement. It can not only give full play to the inherent catalytic desorption effect of the catalyst itself and the efficiency enhancement of gas-liquid mass transfer resistance by CO2 purging, but also ensure the continuous renewal of the contact surface between the catalyst and the absorbent by the scouring and vibration effect of CO2 purging bubbles, promoting full contact between the active sites and the absorbent, so as to effectively improve the catalytic desorption effect of the catalyst and achieve a 1+1>2 effect.

[0059] In the above embodiments, the system includes at least two stages of catalytic packing layers 2-2, each catalytic packing layer 2-2 is arranged at intervals along the height direction, and a jet nozzle is provided below each stage of catalytic packing layer 2-2 to further improve the flushing effect of carbon dioxide on the catalytic packing layer 2-2.

[0060] Specifically, the desorption tower 2 includes a first connection port and a second connection port, which are respectively connected to the two ends of the liquid inlet heat exchange tube of the reboiler. The first connection port is located below the bottommost catalytic packing layer 2-2, and the second connection port is located between the topmost catalytic packing layer 2-2 and the bottommost desorption packing layer 2-1.

[0061] Furthermore, the system also includes a gas-liquid separator 12, which is installed in the gas outlet pipeline of the desorption tower 2, and the liquid medium outlet of the gas-liquid separator 12 is connected to the inner cavity of the absorption tower where the absorption liquid is provided.

[0062] A lean liquid pump 13 is also installed on the connecting pipeline between the lean liquid outlet of the desorption tower 2 and the lean liquid return port of the absorption tower 1 to provide the flow power of the lean liquid.

[0063] Figure 2The specific working principle of the provided system is as follows: High-humidity raw flue gas with a temperature of 130℃~180℃ and a moisture content of 10%~30% enters the reboiler 3 and the flue gas-rich liquid heat exchanger 8, respectively. It then passes through the first-stage flue gas cooler 4 and the second-stage flue gas cooler 5, undergoing multiple cooling processes to reduce the flue gas temperature to the optimal CO2 absorption temperature (around 40℃). The flue gas then enters the absorption tower 1, where it comes into counter-current contact with the absorbent from the lean liquid cooler 9 and the interstage cooler 10. CO2 is efficiently captured by the absorbent. The flue gas is then discharged after passing through the scrubbing section and demister of the absorption tower 1. The CO2-absorbed rich liquid is transported by the rich liquid pump 6 and first enters the lean-rich liquid heat exchanger 7. The liquid is heated to over 90°C by heat exchange with the lean liquid, and then further heated in the flue gas-rich liquid heat exchanger 8 before entering the desorption tower 2. A portion of the CO2 is desorbed from the CO2, which then enters the packing section and bottom catalytic desorption section of the desorption tower 2 for efficient desorption and regeneration. The CO2 discharged from the top of the catalytic desorption tower 2 is cooled in the gas cooler 11, and after passing through the gas-liquid separator 12, part of it enters the subsequent CO2 concentration system, and the other part enters the bottom catalytic desorption section of the desorption tower 2 for CO2 injection purging to improve the catalyst's effect and the desorption efficiency of the desorption tower 2. The heat from the desorption tower 2 is provided by heat exchange between the bottom lean liquid and the raw flue gas from the reboiler 3, and by heat exchange between the top rich liquid and the flue gas-rich liquid heat exchanger 8. The regenerated lean liquid is pumped from the bottom of the desorption tower 2 to the lean-rich liquid heat exchanger 7 via the lean liquid pump 13, where it exchanges heat with the rich liquid for cooling. It then enters the lean liquid cooler 9 for further cooling to approximately 40°C before entering the absorption tower 1, thus achieving absorption liquid circulation. Cooling water from the outlets of the second-stage flue gas cooler 5, interstage cooler 10, lean liquid cooler 9, and gas cooler 11 merges and enters the cold water inlet of the first-stage flue gas heat exchanger to exchange heat with the flue gas, thereby achieving a further cooling of the flue gas.

[0064] The present invention has provided a detailed description of a flue gas carbon dioxide capture process system. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A flue gas carbon dioxide capture process system, characterized in that, Includes the following components; An absorption tower has a flue gas inlet, a flue gas outlet, and a rich liquid outlet. The absorption tower is used to absorb part of the carbon dioxide in the flue gas to form a rich liquid. A desorption tower, the rich liquid inlet of which is connected to the rich liquid outlet of the absorption tower, is used to desorb the rich liquid to generate carbon dioxide gas; The reboiling tower has a flue gas heat exchange tube inside. The flue gas inlet of the flue gas heat exchange tube is connected to the flue gas pipeline of the system to convert part of the sensible heat and latent heat of the flue gas into the heat required for the rich liquid in the desorption tower to desorb carbon dioxide gas. The flue gas outlet of the flue gas heat exchange tube of the reboiling tower can be connected to the flue gas inlet of the absorption tower, and the connecting pipeline between the two is also provided with a regulating component for adjusting the parameters of the flue gas entering the absorption tower to predetermined operating parameters, including at least one of temperature and pressure. The regulating component includes at least one flue gas cooler, and each flue gas cooler is connected in series on the connecting pipeline between the flue gas outlet of the reboiling tower and the flue gas inlet of the absorption tower. The absorption tower has at least two stages of absorbent packing layers between its inlet and outlet, with each absorbent packing layer arranged at intervals. It also includes an interstage cooler for cooling the absorbent liquid located between the two absorbent packing layers. Along the flue gas flow direction, each of the flue gas coolers is defined as a first-stage flue gas cooler to a M-stage flue gas cooler. It also includes a lean liquor cooler for cooling the lean liquor flowing out of the desorption tower; It also includes a gas cooler for cooling the carbon dioxide gas flowing out of the desorption tower; The cooling medium after heat exchange between the interstage cooler, the Mth stage flue gas cooler, the gas cooler, and the lean liquid cooler converges and flows into the first stage flue gas cooler. The desorption tower includes an N-stage desorption packing layer and at least one-stage catalytic packing layer. The desorption packing layer provides a contact surface for the gas and liquid phases, while the catalytic packing layer reduces the energy required for CO2 desorption, lowers the desorption temperature, promotes desorption efficiency, and reduces regeneration energy consumption. The N-stage desorption packing layers are spaced apart along the height of the desorption tower, and the catalytic packing layer is located below all the desorption packing layers. The desorption tower also has a jet outlet located below the catalytic packing layer, which is connected to the gas outlet pipeline of the desorption tower.

2. The flue gas carbon dioxide capture process system as described in claim 1, characterized in that, A flue gas-rich liquid heat exchanger is installed on the connecting pipeline between the rich liquid outlet of the absorption tower and the rich liquid inlet of the desorption tower. The flue gas-rich liquid heat exchanger is used to exchange heat between the flue gas and the rich liquid flowing through it, so as to preheat the rich liquid.

3. The flue gas carbon dioxide capture process system as described in claim 2, characterized in that, The interstage cooler is located outside the absorption tower. An absorbent outlet and an interstage absorbent inlet are provided between adjacent absorbent packing layers of the absorption tower. The two ends of the heat exchange channel inside the interstage cooler are respectively connected to the absorbent outlet and the interstage absorbent inlet.

4. The flue gas carbon dioxide capture process system as described in claim 1, characterized in that, It includes at least two levels of the catalytic packing layer, each of the catalytic packing layers is arranged at intervals along the height direction, and a jet port is provided below each level of the catalytic packing layer.

5. The flue gas carbon dioxide capture process system according to any one of claims 1 to 4, characterized in that, The desorption tower includes a first connection port and a second connection port, which are respectively connected to the two ends of the liquid inlet heat exchange tube of the reboiler. The first connection port is located below the bottommost catalytic packing layer, and the second connection port is located between the topmost catalytic packing layer and the bottommost desorption packing layer.

6. The flue gas carbon dioxide capture process system according to any one of claims 1 to 4, characterized in that, It also includes a gas-liquid separator, which is installed in the gas outlet pipeline of the desorption tower, and the liquid medium outlet of the gas-liquid separator is connected to the inner cavity of the absorption tower where the absorbent is provided.

7. The flue gas carbon dioxide capture process system according to any one of claims 1 to 4, characterized in that, It also includes a rich-lean liquid heat exchanger for exchanging heat between the rich liquid flowing out of the absorption tower and the lean liquid flowing out of the desorption tower; Alternatively / and, a rich liquid pump is also provided on the connecting pipeline between the rich liquid outlet of the absorption tower and the rich liquid inlet of the desorption tower. Alternatively / and, a lean liquid pump is also provided on the connecting pipeline between the lean liquid outlet of the desorption tower and the lean liquid return port of the absorption tower.

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