Converter gas carbon recovery system

Abstract

The application provides a converter gas carbon recovery system and method, and relates to the technical field of steel metallurgy. The converter gas carbon recovery system comprises a fluctuation steady-state device, a carbon dioxide capture device and a carbon monoxide recovery device. The carbon dioxide capture device comprises an absorption tower and a regeneration tower. The absorption tower is provided with a first gas inlet, a first liquid outlet, a first gas outlet and a first liquid inlet. The first gas inlet is communicated with the outlet of the fluctuation steady-state device. The regeneration tower is provided with a second liquid inlet, a second gas outlet, a second liquid outlet, a steam inlet and a condensed water outlet. The second liquid inlet is communicated with the first liquid outlet, and the second liquid outlet is communicated with the first liquid inlet. The carbon monoxide recovery device comprises a deoxidation tower, a carbon monoxide adsorption tower and a degreasing tower connected in sequence. The inlet of the deoxidation tower is communicated with the first gas outlet. The application can solve the problem that the existing converter gas is directly discharged or simply combusted, which not only causes a large amount of greenhouse gas emission, but also wastes the carbon resources contained therein.

Description

Technical Field

[0001] This application relates to the field of iron and steel metallurgy technology, and in particular to a converter gas carbon recovery system. Background Technology

[0002] The steel industry is a typical high-energy-consuming and high-emission industrial sector, with its carbon emissions accounting for about 30% of the total industrial emissions. The task of emission reduction is arduous, and it faces a severe challenge in achieving the "dual carbon" target.

[0003] The gas produced in the traditional converter smelting process is rich in carbon dioxide, which is usually directly emitted or simply burned. This not only causes a large amount of greenhouse gas emissions, but also wastes the carbon resources contained therein. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of this application is to provide a converter gas carbon recovery system.

[0005] This application provides the following technical solution: A converter gas carbon recovery system, comprising: The fluctuation stabilization device has an inlet that allows converter gas to enter. A carbon dioxide capture device includes an absorption tower and a regeneration tower. The absorption tower has a first air inlet and a first liquid outlet at its bottom, and a first air outlet and a first liquid inlet at its top. The first air inlet is connected to the outlet of a fluctuation stabilization device. The regeneration tower has a second liquid inlet and a second air outlet at its top, and a second liquid outlet, a steam inlet, and a condensate outlet at its bottom. The second liquid inlet is connected to the first liquid outlet, and the second liquid outlet is connected to the first liquid inlet. A carbon monoxide recovery device includes a deoxygenation tower, a carbon monoxide adsorption tower, and a degreasing tower. The inlet of the deoxygenation tower is connected to the first gas outlet, the outlet of the deoxygenation tower is connected to the inlet of the carbon monoxide adsorption tower, and the outlet of the carbon monoxide adsorption tower is connected to the inlet of the degreasing tower.

[0006] As a further optional solution for the converter gas carbon recovery system, the fluctuation stabilization device includes a buffer pressure stabilizing container, a perforated distribution plate, a pressure regulating valve, and a variable frequency fan. The inlet of the buffer pressure stabilizing container is for converter gas to enter, and the outlet of the buffer pressure stabilizing container is connected to the first gas inlet through the pressure regulating valve and the variable frequency fan. The perforated distribution plate is disposed inside the buffer pressure stabilizing container.

[0007] As a further optional feature of the converter gas carbon recovery system, the top of the buffer pressure stabilizing vessel is provided with a safety vent; and / or The bottom of the buffer pressure stabilizing container is provided with a drain port; and / or The outlet of the buffer pressure stabilizing vessel is equipped with an online flow analyzer and an online pressure analyzer.

[0008] As a further optional solution for the converter gas carbon recovery system, the carbon dioxide capture device also includes a rich liquid degasser, which is disposed between the first liquid outlet and the second liquid inlet, and the operating pressure of the rich liquid degasser is 0.02-0.1 MPaA. The rich liquid degasser is provided with a third liquid inlet, a third liquid outlet and a third gas outlet. The third liquid inlet is connected to the first liquid outlet, the third liquid outlet is connected to the second liquid inlet and the third gas outlet is connected to the carbon monoxide recovery device.

[0009] As a further optional solution to the converter gas carbon recovery system, the carbon dioxide capture device also includes a heat exchanger, which is disposed between the first liquid outlet and the second liquid inlet. The heat exchanger is provided with a first channel and a second channel. The inlet of the first channel is connected to the first liquid outlet, the outlet of the first channel is connected to the second liquid inlet, the inlet of the second channel is connected to the second liquid outlet, and the outlet of the second channel is connected to the first liquid inlet.

[0010] As a further optional feature of the converter gas carbon recovery system, the regeneration tower is provided with a reflux port; The carbon dioxide capture device further includes a reflux pump and a gas-liquid separator. The inlet of the reflux pump is connected to the second gas outlet, the outlet of the reflux pump is connected to the inlet of the gas-liquid separator, and the liquid outlet of the gas-liquid separator is connected to the reflux port.

[0011] As a further optional feature of the converter gas carbon recovery system, the carbon monoxide adsorption tower is provided with at least two towers. The carbon monoxide adsorption tower is equipped with a backflush port, and the outlet of the carbon monoxide adsorption tower is also connected to the backflush port.

[0012] As a further optional solution to the converter gas carbon recovery system, the converter gas carbon recovery system also includes a dust collector, the inlet of which allows converter gas to enter, and the exhaust port of the dust collector is connected to the inlet of the fluctuation stabilization device.

[0013] As a further optional feature of the converter gas carbon recovery system, the converter gas carbon recovery system also includes a water washing tower, which is located between the fluctuation stabilization device and the absorption tower.

[0014] As a further optional feature of the converter gas carbon recovery system, the gas flow rate of the empty tower of the absorption tower and / or the regeneration tower is designed to be 50%-80% of the flooding point gas velocity.

[0015] The embodiments of this application have the following beneficial effects: During operation of the converter gas carbon recovery system, the converter gas is fed into a fluctuation stabilization device. This device buffers, homogenizes, and stabilizes the converter gas supply, then outputs a stable supply of converter gas to the first inlet at the bottom of the absorber tower. Simultaneously, lean absorbent is transported to the first liquid inlet at the top of the absorber tower. Inside the absorber tower, the converter gas flows upwards, making full countercurrent contact with the lean absorbent sprayed downwards. During this contact, the lean absorbent selectively captures carbon dioxide from the converter gas, generating rich liquid, which is discharged from the first liquid outlet at the bottom of the absorber tower and then enters the top of the regeneration tower through the second liquid inlet. Simultaneously, high-temperature steam is transported to the steam inlet at the bottom of the regeneration tower. Inside the regeneration tower, the rich liquid flows downwards, making countercurrent contact with the upward-flowing steam, thereby releasing carbon dioxide and regenerating lean liquid. The released carbon dioxide is discharged from the second gas outlet at the top of the regeneration tower, yielding carbon dioxide product gas. The regenerated lean liquid is discharged through the second outlet at the bottom of the regeneration tower to the first inlet at the top of the absorption tower for reabsorbing carbon dioxide. Additionally, the cooled steam becomes condensate and is discharged from the condensate outlet at the bottom of the regeneration tower. The remaining gas after carbon dioxide capture is discharged through the first outlet at the top of the absorption tower to the carbon monoxide recovery unit, where it undergoes deoxygenation in a deoxygenation tower, adsorption in a carbon monoxide adsorption tower, and degreasing in a degreasing tower to obtain carbon monoxide product gas. Thus, the above-mentioned converter gas carbon recovery system completes the capture of carbon dioxide and the purification and recovery of carbon monoxide from converter gas, significantly reducing greenhouse gas emissions and fully utilizing the carbon resources contained in the converter gas. In particular, the fluctuation stabilization device buffers, homogenizes, and stabilizes the supply of converter gas, allowing the flow rate, pressure, and composition of the converter gas to fluctuate within a smaller range. This effectively mitigates the adverse effects of the converter gas's characteristics—intermittent gas production per furnace, fluctuating flow / composition, and fluctuating oxygen content—on carbon dioxide capture and carbon monoxide purification and recovery.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the converter gas carbon recovery system in an embodiment of this application is shown; Figure 2 A schematic diagram of the fluctuation stabilization device in an embodiment of this application is shown.

[0019] Explanation of key component symbols: 100. Fluctuation stabilization device; 101. Buffer and pressure stabilizing vessel; 102. Perforated distribution plate; 103. Pressure regulating valve; 104. Variable frequency fan; 105. Safety vent; 106. Drain outlet; 107. Online flow analyzer; 108. Online pressure analyzer; 109. Inlet shut-off valve; 110. Outlet gate valve; 200. Carbon dioxide capture device; 201. Absorption tower; 202. Regeneration tower; 203. Heat exchanger; 204. Rich liquid pump; 205. 206. First cooler; 207. Rich liquid degasser; 208. Lean liquid pump; 209. Reflux pump; 200. Gas-liquid separator; 210. Second cooler; 211. Reboiler; 300. Carbon monoxide recovery unit; 301. Deoxygenation tower; 302. Carbon monoxide adsorption tower; 303. Degreasing tower; 304. First compressor; 305. Vacuum pump; 306. Second compressor; 400. Dust collector; 500. Flue gas analyzer; 600. Water scrubbing tower; 700. Flue gas fan. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0021] Achieving efficient capture and resource utilization of carbon dioxide during steel production has become a key path for the industry's green transformation and is of great significance for promoting the low-carbon and sustainable development of the steel industry.

[0022] Converter gas is a by-product gas produced during the converter steelmaking process. Its main components are carbon monoxide (32%-55%) and carbon dioxide (15%-25%), while also containing small amounts of nitrogen, oxygen and steelmaking dust. It has the basic conditions to serve as a carbon dioxide capture gas source.

[0023] The inventors of this application have discovered that, compared to other industrial flue gas (such as coal-fired flue gas), converter gas has the characteristics of moderate temperature, lower pressure, and relatively controllable impurities, making it easier to undergo subsequent purification and separation treatment. Furthermore, converter gas itself contains high-value carbon monoxide components. If carbon monoxide can be purified and recovered while capturing carbon dioxide, not only can carbon emissions be reduced, but also the cascade utilization of resources can be achieved. It is an ideal gas source for the synergistic treatment of low-to-medium concentration carbon dioxide capture and resource recovery.

[0024] However, converter gas has significant characteristics such as "intermittent gas production per furnace, fluctuations in flow rate / composition, fluctuations in oxygen content, and fluctuations in dust," which leads to the following problems in the engineering application of traditional continuous carbon dioxide chemical absorption-regeneration systems and carbon monoxide adsorption purification systems: (1) Fluctuations in the operating conditions of the absorption-regeneration loop lead to a deterioration in the capture rate and energy consumption; (2) The combustible gases entrained / dissolved in the rich solution cause carbon monoxide loss and safety risks in the regeneration section; (3) The purification unit is sensitive to oxygen, which can easily lead to a shortened adsorbent life and frequent triggering of safety interlocks.

[0025] Therefore, there is an urgent need for a system and method that can continuously and stably produce carbon dioxide and carbon monoxide product gas under fluctuating converter gas conditions, while reducing carbon monoxide loss.

[0026] For this purpose, please refer to Figure 1 The embodiments of this application provide a converter gas carbon recovery system, including a fluctuation stabilization device 100, a carbon dioxide capture device 200, and a carbon monoxide recovery device 300.

[0027] The inlet of the fluctuation stabilization device 100 can be used to allow converter gas to enter.

[0028] The carbon dioxide capture device 200 includes an absorption tower 201 and a regeneration tower 202. The absorption tower 201 has a first air inlet and a first liquid outlet at its bottom, and a first air outlet and a first liquid inlet at its top. The first air inlet is connected to the outlet of the fluctuation stabilization device 100. The regeneration tower 202 has a second liquid inlet and a second air outlet at its top, and a second liquid outlet, a steam inlet, and a condensate outlet at its bottom. The second liquid inlet is connected to the first liquid outlet, and the second liquid outlet is connected to the first liquid inlet.

[0029] The carbon monoxide recovery device 300 includes a deoxygenation tower 301, a carbon monoxide adsorption tower 302, and a degreasing tower 303. The inlet of the deoxygenation tower 301 is connected to the first gas outlet, the outlet of the deoxygenation tower 301 is connected to the inlet of the carbon monoxide adsorption tower 302, and the outlet of the carbon monoxide adsorption tower 302 is connected to the inlet of the degreasing tower 303.

[0030] When the aforementioned converter gas carbon recovery system is in operation, the converter gas is fed into the fluctuation stabilization device 100. The fluctuation stabilization device 100 buffers, homogenizes, and stabilizes the pressure of the converter gas, and then outputs a steady-state supply of converter gas to the first gas inlet at the bottom of the absorption tower 201. At the same time, the lean absorbent is transported to the first liquid inlet at the top of the absorption tower 201.

[0031] Inside absorber 201, converter gas flows from bottom to top, making full countercurrent contact with lean absorbent sprayed from top to bottom. During this contact, the lean absorbent selectively captures carbon dioxide from the converter gas, generating rich liquid, which is discharged from the first outlet at the bottom of absorber 201 and then enters the top of regeneration tower 202 through the second inlet. Simultaneously, high-temperature steam is transported to the steam inlet at the bottom of regeneration tower 202. Inside regeneration tower 202, the rich liquid flows from top to bottom, making countercurrent contact with the steam flowing from bottom to top, thereby releasing carbon dioxide and regenerating lean liquid. The released carbon dioxide is discharged from the second outlet at the top of regeneration tower 202, yielding carbon dioxide product gas. The regenerated lean liquid is discharged through the second outlet at the bottom of regeneration tower 202 to the first inlet at the top of absorber 201 for reabsorbing carbon dioxide. Furthermore, the cooled steam becomes condensate, which is discharged from the condensate outlet at the bottom of regeneration tower 202.

[0032] After capturing carbon dioxide, the remaining gas is discharged to the carbon monoxide recovery device 300 through the first outlet at the top of the absorption tower 201. After passing through the deoxygenation tower 301 for deoxygenation, the carbon monoxide adsorption tower 302 for adsorption, and the degreasing tower 303 for degreasing, carbon monoxide product gas is obtained.

[0033] Therefore, the converter gas carbon recovery system described above completes the capture of carbon dioxide and the purification and recovery of carbon monoxide in converter gas, which can greatly reduce greenhouse gas emissions and make full use of the carbon resources contained in converter gas.

[0034] In particular, the fluctuation stabilization device 100 buffers, homogenizes, and stabilizes the supply of converter gas, allowing the flow rate, pressure, and composition of the converter gas to fluctuate within a smaller range. This effectively mitigates the adverse effects of the characteristics of converter gas, such as "intermittent gas production per furnace, fluctuations in flow rate / composition, and fluctuations in oxygen content," on carbon dioxide capture and carbon monoxide purification and recovery. Specifically, it can improve the capture rate and energy consumption deterioration caused by fluctuations in the operating conditions of the carbon dioxide capture device 200, improve the shortened lifespan of the adsorbent in the carbon monoxide adsorption tower 302 due to excessive oxygen content, and improve the frequent triggering of safety interlocks caused by large fluctuations in the oxygen content of the gas entering the carbon monoxide recovery device 300.

[0035] In some embodiments, the converter gas carbon recovery system described above further includes a dust collector 400. The inlet of the dust collector 400 is for converter gas to enter, and the exhaust port of the dust collector 400 is connected to the inlet of the fluctuation stabilization device 100.

[0036] In operation, the converter gas first enters the dust collector 400, where it undergoes pretreatment including dust removal, cooling, and demisting to obtain pretreated converter gas. This pretreated gas is then introduced into the inlet of the fluctuation stabilization device 100, thereby mitigating the adverse effects of the converter gas's "dust fluctuations" on carbon dioxide capture and carbon monoxide purification and recovery. Specifically, it reduces the impact of dust and droplet entrainment on the solvent and adsorbent. The separated dust is discharged from the ash discharge port of the dust collector 400.

[0037] In this embodiment, the dust content in the converter gas after passing through dust collector 400 is less than 5 mg / Nm³. 3 .

[0038] In this embodiment, a flue gas analyzer 500 is provided between the exhaust port of the dust collector 400 and the inlet of the fluctuation stabilization device 100 to analyze the content of components such as carbon dioxide, carbon monoxide and oxygen in the pretreated converter gas.

[0039] Please see Figure 2 In some embodiments, the fluctuation stabilization device 100 includes a buffer pressure stabilizing container 101, a porous distribution plate 102, a pressure regulating valve 103, and a variable frequency fan 104.

[0040] The inlet of the buffer pressure stabilizing container 101 is for the intake of converter gas, specifically connected to the exhaust port of the dust collector 400 for the intake of pretreated converter gas. The outlet of the buffer pressure stabilizing container 101 is connected to the first air inlet via a pressure regulating valve 103 and a variable frequency fan 104. A perforated distribution plate 102 is disposed inside the buffer pressure stabilizing container 101.

[0041] When the pretreated converter gas enters the inlet of the buffer and pressure stabilizing container 101, the effective gas volume of the buffer and pressure stabilizing container 101 absorbs the instantaneous flow shock, and the residence time is extended and the local concentration pulsation is weakened by the porous distribution plate 102. In addition, the pressure regulating valve 103 and the variable frequency fan 104 work together to achieve stable output. That is to say, through the synergistic effect of volume buffering, rectification and homogenization and throttling and pressure stabilization, the flow rate, pressure and composition of the converter gas fluctuate within a smaller range, so as to obtain a steady-state supply of converter gas.

[0042] In this embodiment, the buffer pressure stabilizing container 101 is a gas holder, a pressure stabilizing tank, or a combination of both, and its buffering capacity is an equivalent residence time of 0.5-10 min, preferably 2-5 min. Furthermore, the flow rate fluctuation of the converter gas output from the fluctuation stabilization device 100 under a 1-5 min moving average is no greater than ±10% of the design value, the pressure fluctuation is no greater than ±0.5 kPa, the carbon dioxide volume fraction fluctuation is no greater than ±1.5 vol.%, the carbon monoxide volume fraction fluctuation is no greater than ±2.0 vol.%, and the oxygen volume fraction is controlled below 0.5 vol.%, preferably below 0.3 vol.%.

[0043] Furthermore, in some embodiments, the top of the buffer pressure stabilizing container 101 is provided with a safety vent 105, which can be used to discharge converter gas in an emergency to avoid damage to the equipment.

[0044] Furthermore, in some embodiments, the bottom of the buffer pressure stabilizing container 101 is provided with a drain port 106 to discharge the condensate separated when the converter gas flows through the porous distribution plate 102.

[0045] Furthermore, in some embodiments, the outlet of the buffer pressure stabilizing vessel 101 is provided with an online flow analyzer 107 and an online pressure analyzer 108.

[0046] Among them, the online flow analyzer 107 can monitor the flow rate of converter gas online, so that the external control system can determine whether the flow rate fluctuation of converter gas is not greater than ±10% of the design value. The online pressure analyzer 108 can monitor the pressure of converter gas online, so that the external control system can determine whether the pressure fluctuation of converter gas is not greater than ±0.5kPa.

[0047] In this embodiment, the inlet of the buffer pressure stabilizing container 101 is equipped with an inlet shut-off valve 109, which can disconnect the connection between the buffer pressure stabilizing container 101 and the dust collector 400. The outlet of the buffer pressure stabilizing container 101 is equipped with an outlet gate valve 110, which can disconnect the connection between the buffer pressure stabilizing container 101 and the absorption tower 201.

[0048] Please refer to it again. Figure 1 In some embodiments, the converter gas carbon recovery system further includes a water washing tower 600, which is disposed between the fluctuation stabilization device 100 and the absorption tower 201.

[0049] When in use, the converter gas is cooled by direct spraying of washing liquid inside the water washing tower 600. The carbon dioxide in the cooled converter gas can be better absorbed and captured by the lean liquid absorbent.

[0050] In this embodiment, the pH value of the washing solution is 6-8. The temperature of the converter gas after water washing and cooling is 30-50℃, and the pressure is 4-6 kPaG.

[0051] In this embodiment, a flue gas fan 700 is provided between the outlet of the buffer pressure stabilizing container 101 and the inlet of the water washing tower 600. The steady-state supplied converter gas is pressurized by the flue gas fan 700 and then enters the water washing tower 600.

[0052] In some embodiments, the carbon dioxide capture device 200 further includes a heat exchanger 203 disposed between the first liquid outlet and the second liquid inlet.

[0053] The heat exchanger 203 has a first channel and a second channel. The inlet of the first channel is connected to the first liquid outlet, and the outlet of the first channel is connected to the second liquid inlet. The inlet of the second channel is connected to the second liquid outlet, and the outlet of the second channel is connected to the first liquid inlet.

[0054] In operation, the rich liquor is discharged from the first outlet at the bottom of the absorption tower 201, flows through the first channel, and enters the second inlet at the top of the regeneration tower 202. The regenerated lean liquor is discharged from the second outlet at the bottom of the regeneration tower 202, flows through the second channel, and enters the first inlet at the top of the absorption tower 201. During this process, the rich liquor absorbs heat from the regenerated lean liquor, causing its temperature to rise, which allows for further heating within the regeneration tower 202 to release carbon dioxide; conversely, the temperature of the regenerated lean liquor decreases, allowing for better absorption and capture of carbon dioxide within the absorption tower 201.

[0055] In this embodiment, a rich liquid pump 204 is provided between the first liquid outlet and the inlet of the first channel to pump the rich liquid discharged from the first liquid outlet.

[0056] In this embodiment, a lean liquid pump 207 is provided between the second outlet and the inlet of the second channel to pump the lean liquid discharged from the second outlet.

[0057] In this embodiment, a first cooler 205 is provided between the outlet of the second channel and the first inlet to further cool and lower the temperature of the lean liquid after heat exchange.

[0058] In this embodiment, the temperature of the lean liquid flowing out from the bottom of the regeneration tower 202 is 100-110°C, and the temperature of the lean liquid entering the absorption tower 201 is 25-60°C. Furthermore, an alkaline absorbent is used for the lean liquid.

[0059] In some embodiments, the carbon dioxide capture device 200 further includes a rich liquid degasser 206. The rich liquid degasser 206 is disposed between the first liquid outlet and the second liquid inlet, and the operating pressure of the rich liquid degasser 206 is 0.02-0.1 MPaA.

[0060] The rich liquid degasser 206 is equipped with a third liquid inlet, a third liquid outlet, and a third gas outlet. The third liquid inlet is connected to the first liquid outlet, the third liquid outlet is connected to the second liquid inlet, and the third gas outlet is connected to the carbon monoxide recovery device 300.

[0061] In operation, the rich liquor is first introduced into the third inlet of the rich liquor degasser 206 before entering the regeneration tower 202. Inside the rich liquor degasser 206, in a near-vacuum environment, entrained or dissolved carbon monoxide is released, forming degassed gas. This degassed gas is discharged from the third outlet of the rich liquor degasser 206 to the carbon monoxide recovery unit 300. This avoids carbon monoxide loss and safety risks caused by entrained / dissolved combustible gases in the rich liquor during the regeneration section, while simultaneously improving the quality of the carbon dioxide product gas.

[0062] In addition, the rich liquid after releasing carbon monoxide is discharged from the third outlet of the rich liquid degassing section and enters the second inlet at the top of the regeneration tower 202.

[0063] In this embodiment, the first liquid outlet and the first channel of the absorption tower 201, the third liquid inlet of the rich liquid degasser 206, the third liquid outlet of the rich liquid degasser 206, and the second liquid inlet of the regeneration tower 202 are connected in sequence.

[0064] In some embodiments, the regeneration tower 202 is provided with a reflux port. Accordingly, the carbon dioxide capture device 200 also includes a reflux pump 208 and a gas-liquid separator 209.

[0065] The inlet of the reflux pump 208 is connected to the second air outlet, the outlet of the reflux pump 208 is connected to the inlet of the gas-liquid separator 209, and the liquid outlet of the gas-liquid separator 209 is connected to the reflux port.

[0066] In use, the carbon dioxide gas desorbed in the regeneration tower 202 is discharged from the second outlet at the top of the regeneration tower 202. After being pressurized by the reflux pump 208, it passes through the gas-liquid separator 209 to obtain dry carbon dioxide product gas. The remaining alkaline absorbent carrying a small amount of carbon dioxide is replenished into the regeneration tower 202 through the liquid outlet of the gas-liquid separator 209, where it merges with the lean liquid to complete the carbon dioxide capture process.

[0067] In this embodiment, a second cooler 210 is provided between the liquid outlet and the return port of the gas-liquid separator 209 to cool the remaining alkaline absorbent.

[0068] In some embodiments, the carbon dioxide capture device 200 further includes a reboiler 211. The gas outlet of the reboiler 211 is connected to the steam inlet at the bottom of the regeneration tower 202, providing high-temperature steam to the regeneration tower 202. The liquid inlet of the reboiler 211 is connected to the condensate outlet at the bottom of the regeneration tower 202, allowing condensate to be returned.

[0069] In this embodiment, a first compressor 304 is provided between the first gas outlet at the top of the absorption tower 201 and the inlet of the deoxygenation tower 301. The gas remaining after carbon dioxide capture is pressurized by the first compressor 304 and enters the top of the deoxygenation tower 301 to remove residual oxygen, and then exhausts as tail gas. The main components of this tail gas are nitrogen, carbon dioxide, and oxygen.

[0070] The deoxygenated carbon monoxide-rich gas enters the carbon monoxide adsorption tower 302, where carbon monoxide is separated from the gas to obtain industrial-grade carbon monoxide gas, which is then discharged from the adsorption tower 302 as tail gas. The main components of this tail gas are nitrogen and a small amount of carbon monoxide.

[0071] In this embodiment, the converter gas carbon recovery system also includes a control and safety interlock device.

[0072] Specifically, the control and safety interlock device includes an oxygen content interlock, which triggers a bypass or emergency shut-off when the oxygen content before entering the deoxygenation tower 301 is greater than a preset threshold, ensuring the safe operation of the carbon monoxide purification and recovery process.

[0073] In some embodiments, the carbon monoxide adsorption tower 302 is provided with at least two.

[0074] In addition, the carbon monoxide adsorption tower 302 is equipped with a backflush port, and the outlet of the carbon monoxide adsorption tower 302 is also connected to the backflush port.

[0075] During operation, a small amount of industrial-grade carbon monoxide gas is returned to the backflush port of the carbon monoxide adsorption tower 302 for purging, regenerating the adsorbent. The remaining industrial-grade carbon monoxide gas is then passed through the degreasing tower 303 to obtain carbon monoxide product gas, completing the carbon monoxide purification and recovery process.

[0076] Understandably, at least two carbon monoxide adsorption towers 302 can take turns performing purging operations to ensure that at least one carbon monoxide adsorption tower 302 is always in the adsorption step.

[0077] In this embodiment, there are eight carbon monoxide adsorption towers 302. At any given time, two carbon monoxide adsorption towers 302 are in the adsorption step, while the remaining carbon monoxide adsorption towers 302 are in different stages of adsorbent regeneration.

[0078] In this embodiment, the carbon monoxide recovery device 300 further includes a vacuum pump 305 and a second compressor 306. The outlet of the carbon monoxide adsorption tower 302 is connected to the inlet of the second compressor 306 through the vacuum pump 305, and the outlet of the second compressor 306 is connected to the backflush port and the inlet of the degreasing tower 303, respectively.

[0079] During use, industrial-grade carbon monoxide gas is extracted by vacuum pump 305, compressed and pressurized by second compressor 306, and a small amount is returned to carbon monoxide adsorption tower 302 for purging.

[0080] In some embodiments, the gas flow rate of the empty tower of the absorption tower 201 and / or regeneration tower 202 is designed to be 50%-80% of the flooding point gas velocity.

[0081] Specifically, the flooding point velocity is defined as follows: In a packed tower operating in countercurrent flow, as the gas phase velocity increases, the resistance to the countercurrent flow of the liquid phase continuously increases. When the gas phase velocity increases to a certain critical value, the liquid phase can no longer flow smoothly in countercurrent flow, begins to accumulate in the packing layer, and is largely entrained by the gas flow, thus disrupting the normal countercurrent operation within the tower. This critical state is called "flooding," and the corresponding gas phase velocity is called the "flooding point velocity."

[0082] Taking absorber 201 as an example, the formula for calculating its flooding velocity is as follows: ; Where: u F The calculated flooding velocity (m / s); k is the flooding constant, dimensionless; ρ l The density of the lean liquid (kg / m³) 3 ); ρ g Density of gas entering the tower (kg / m³) 3 ).

[0083] In this embodiment, the value range of the generalization constant k is 0.01-0.2 m / s.

[0084] It should be noted that the design size of the carbon dioxide capture unit 200 and the carbon monoxide recovery unit 300 should be determined based on the converter production conditions and the scale of gas generation. The specific design process is as follows: The first step is to determine the amount of converter gas recovered in the steel plant. The amount of gas recovered per ton of steel produced by converter smelting ranges from 110 to 180 Nm³ for different steel plants. 3 Between / t, the annual converter gas processing capacity is obtained by multiplying the steel plant output by the gas recovery amount.

[0085] The second step is to collect information on the composition of the converter gas.

[0086] Specifically, the range of values ​​for the converter gas composition is shown in Table 1:

[0087] Table 1. Content of major components in converter gas The third step involves designing the carbon dioxide capture and carbon monoxide recovery quantities for carbon dioxide absorption and capture and carbon monoxide purification and recovery based on the converter gas composition and processing capacity. The calculation process is as follows: Carbon dioxide capture rate = Converter gas processing capacity * Carbon dioxide content * Capture rate; Carbon monoxide purification and recovery amount = converter gas processing amount * carbon monoxide content * purification rate.

[0088] In summary, the aforementioned converter gas carbon recovery system, designed for intermittent and fluctuating converter gas operation, employs a fluctuation stabilization device 100. Through the synergistic effects of volumetric buffering, rectification homogenization, and pressure stabilization, it controls the fluctuations in flow rate, pressure, composition, and oxygen content of the converter gas before it enters the absorption tower 201 within a set range. This reduces operational disturbances to the carbon dioxide capture device 200 and the carbon monoxide recovery device 300, improving the system's continuous operation stability and product gas quality. Furthermore, carbon monoxide is recovered through the rich liquid degasser 206, reducing carbon monoxide loss in the regeneration section and mitigating the safety risks associated with the top gas of the regeneration tower 202. The deoxygenation and closed-loop adsorption purification structure improves the purity and operational safety of the carbon monoxide product gas, reducing the risk of adsorbent deactivation. This application, considering the compositional characteristics of converter gas, selects the optimal carbon dioxide capture and carbon monoxide purification pathways, enabling significant profits while reducing carbon dioxide emissions.

[0089] The aforementioned converter gas carbon recovery system is applicable to all current long-process steelmaking processes of all scales.

[0090] The blast furnace-converter long-process steelmaking process generates a large amount of converter gas. The main components of converter gas are carbon dioxide and carbon monoxide. Gas production is expressed as per ton of steel production. The range of per ton of steel production and composition range for the long-process process are shown in Table 2.

[0091] Table 2. Converter Gas Quantity and Composition Range per Ton of Steel Sold Through Blast Furnace-Converter Long Process Table 2 covers the generation of converter gas during the converter smelting process in steel plants. The main uses of converter gas when the above-mentioned converter gas carbon recovery system is not used are as follows: Converter gas is currently mainly used in ladle baking, heating furnace baking, and power plant power generation. However, in actual production, a large amount of converter gas is not effectively recovered and utilized, and ultimately can only be released and burned through the combustion tower.

[0092] In practical applications, with 100 Nm 3 Based on converter gas, the implementation results of the above-mentioned converter gas carbon recovery system are as follows: According to statistics, after using the above-mentioned converter gas carbon recovery system, every 100 Nm³ 3 Converter gas can capture 11-23 Nm³ of carbon dioxide. 3 The purified carbon monoxide was 27-52 Nm³. 3 Compared to direct emissions or emissions after combustion of converter gas, carbon dioxide emissions are reduced by 38-75 Nm³.3 .

[0093] Example 1 For a steel plant with a steel production capacity of 3 million tons, the above-mentioned converter gas carbon recovery system was operated, and the results are as follows: The steel plant's gas production per ton of steel is 125 Nm³. 3 The gas composition is 21% carbon dioxide, 40% carbon monoxide, 1.5% hydrogen, 1% oxygen, and 36.5% nitrogen.

[0094] The steel plant's annual converter gas production is approximately 375 million Nm³. 3 The carbon dioxide capture rate of the designed carbon dioxide capture device 200 is 80%, and the carbon monoxide purification rate of the carbon monoxide recovery device 300 is 88%.

[0095] Carbon dioxide capture capacity = converter gas processing capacity * carbon dioxide content * capture rate = 126,000 tons.

[0096] Carbon monoxide purification amount = converter gas processing amount * carbon monoxide content * purification rate = 168,000 tons.

[0097] In the carbon dioxide capture device 200, the flooding constant of the absorption tower 201 and the regeneration tower 202 is taken as 0.05 m / s, and the lean liquor density is 1100 kg / m³. 3 The density of the gas phase entering the tower is 1.2 kg / m³. 3 The generalized point velocity is calculated as follows: .

[0098] The gas velocity in the empty towers of the absorption tower 201 and regeneration tower 202 is taken as 70% of the flooding point gas velocity, so the gas velocity is 1.06 m / s.

[0099] According to statistics from the steel plant's energy department, after operating the aforementioned converter gas carbon recovery system, per 100 Nm³... 3 Converter gas can capture 17 Nm³ of carbon dioxide. 3 The purified carbon monoxide was 35 Nm³. 3 Compared to direct emissions or emissions after combustion of converter gas, the reduction in carbon dioxide emissions is 52 Nm³. 3 The price of converter gas supplied for combustion at this plant is 0.2 yuan / Nm³. 3 The price for carbon monoxide recovery is 1.0 yuan / Nm³. 3 The price for carbon dioxide recovery is 0.6 yuan / Nm³. 3 per 100Nm 3The converter gas carbon recovery system described above can increase profits by 25.28 yuan. With an annual capture of 126,000 tons of carbon dioxide and purification of 168,000 tons of carbon monoxide, it can generate 94.8 million yuan in revenue for steel mills and reduce carbon dioxide emissions by 290,000 tons.

[0100] Example 2 For a steel plant with a steel production capacity of 1 million tons, the above-mentioned converter gas carbon recovery system was operated, and the results are as follows: The steel plant's gas production per ton of steel is 140 Nm³. 3 The gas composition is carbon dioxide -18%, carbon monoxide -45%, hydrogen -1.7%, oxygen -0.8%, and nitrogen -34.5%.

[0101] The steel plant's annual converter gas production is approximately 140 million Nm³. 3 The carbon dioxide capture rate of the designed carbon dioxide capture device 200 is 82%, and the carbon monoxide purification rate of the carbon monoxide recovery device 300 is 90%.

[0102] Carbon dioxide capture capacity = converter gas processing capacity * carbon dioxide content * capture rate = 41,000 tons.

[0103] Carbon monoxide purification amount = converter gas processing amount * carbon monoxide content * purification rate = 72,000 tons.

[0104] In the carbon dioxide capture device 200, the flooding constant of the absorption tower 201 and the regeneration tower 202 is taken as 0.1 m / s, and the lean liquor density is 1050 kg / m³. 3 The density of the gas phase entering the tower is 1.2 kg / m³. 3 The generalized point velocity is calculated as follows: .

[0105] The gas velocity in the empty towers of the absorption tower 201 and regeneration tower 202 is taken as 70% of the flooding point gas velocity, so the gas velocity is 2.07 m / s.

[0106] According to statistics from the steel plant's energy department, after operating the aforementioned converter gas carbon recovery system, per 100 Nm³... 3 Converter gas can capture 15 Nm³ of carbon dioxide. 3 The purified carbon monoxide was 40 Nm³. 3 Compared to direct emissions or emissions after combustion of converter gas, the reduction in carbon dioxide emissions is 55 Nm³. 3 The price of converter gas supplied for combustion at this plant is 0.3 yuan / Nm³. 3 The price for carbon monoxide recovery is 1.0 yuan / Nm³. 3 The price for carbon dioxide recovery is 0.6 yuan / Nm³. 3 per 100Nm 3Using the aforementioned invention and method, converter gas can increase profits by 19.36 yuan. With an annual capture capacity of 41,000 tons of carbon dioxide and purification capacity of 72,000 tons of carbon monoxide, it can generate 27 million yuan in revenue for steel mills and reduce carbon dioxide emissions by 150,000 tons.

[0107] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A converter gas carbon recovery system, characterized in that, include: The fluctuation stabilization device has an inlet that allows converter gas to enter. A carbon dioxide capture device includes an absorption tower and a regeneration tower. The absorption tower has a first air inlet and a first liquid outlet at its bottom, and a first air outlet and a first liquid inlet at its top. The first air inlet is connected to the outlet of a fluctuation stabilization device. The regeneration tower has a second liquid inlet and a second air outlet at its top, and a second liquid outlet, a steam inlet, and a condensate outlet at its bottom. The second liquid inlet is connected to the first liquid outlet, and the second liquid outlet is connected to the first liquid inlet. A carbon monoxide recovery device includes a deoxygenation tower, a carbon monoxide adsorption tower, and a degreasing tower. The inlet of the deoxygenation tower is connected to the first gas outlet, the outlet of the deoxygenation tower is connected to the inlet of the carbon monoxide adsorption tower, and the outlet of the carbon monoxide adsorption tower is connected to the inlet of the degreasing tower.

2. The converter gas carbon recovery system according to claim 1, characterized in that, The fluctuation stabilization device includes a buffer pressure stabilizing container, a perforated distribution plate, a pressure regulating valve, and a variable frequency fan. The inlet of the buffer pressure stabilizing container is for converter gas to enter, and the outlet of the buffer pressure stabilizing container is connected to the first air inlet through the pressure regulating valve and the variable frequency fan. The perforated distribution plate is disposed inside the buffer pressure stabilizing container.

3. The converter gas carbon recovery system according to claim 2, characterized in that, The top of the buffer pressure stabilizing container is provided with a safety vent; and / or The bottom of the buffer pressure stabilizing container is provided with a drain port; and / or The outlet of the buffer pressure stabilizing vessel is equipped with an online flow analyzer and an online pressure analyzer.

4. The converter gas carbon recovery system according to claim 1, characterized in that, The carbon dioxide capture device further includes a rich liquid degasser, which is disposed between the first liquid outlet and the second liquid inlet, and the operating pressure of the rich liquid degasser is 0.02-0.1 MPaA. The rich liquid degasser is provided with a third liquid inlet, a third liquid outlet and a third gas outlet. The third liquid inlet is connected to the first liquid outlet, the third liquid outlet is connected to the second liquid inlet and the third gas outlet is connected to the carbon monoxide recovery device.

5. The converter gas carbon recovery system according to claim 1, characterized in that, The carbon dioxide capture device further includes a heat exchanger, which is disposed between the first liquid outlet and the second liquid inlet; The heat exchanger is provided with a first channel and a second channel. The inlet of the first channel is connected to the first liquid outlet, the outlet of the first channel is connected to the second liquid inlet, the inlet of the second channel is connected to the second liquid outlet, and the outlet of the second channel is connected to the first liquid inlet.

6. The converter gas carbon recovery system according to claim 1, characterized in that, The regeneration tower is equipped with a reflux port; The carbon dioxide capture device further includes a reflux pump and a gas-liquid separator. The inlet of the reflux pump is connected to the second gas outlet, the outlet of the reflux pump is connected to the inlet of the gas-liquid separator, and the liquid outlet of the gas-liquid separator is connected to the reflux port.

7. The converter gas carbon recovery system according to claim 1, characterized in that, The carbon monoxide adsorption tower is provided with at least two; The carbon monoxide adsorption tower is equipped with a backflush port, and the outlet of the carbon monoxide adsorption tower is also connected to the backflush port.

8. The converter gas carbon recovery system according to any one of claims 1 to 7, characterized in that, The converter gas carbon recovery system also includes a dust collector, the inlet of which allows converter gas to enter, and the exhaust port of the dust collector is connected to the inlet of the fluctuation stabilization device.

9. The converter gas carbon recovery system according to any one of claims 1 to 7, characterized in that, The converter gas carbon recovery system also includes a water washing tower, which is located between the fluctuation stabilization device and the absorption tower.

10. The converter gas carbon recovery system according to any one of claims 1 to 7, characterized in that, The gas flow rate of the empty tower of the absorption tower and / or the regeneration tower is designed to be 50%-80% of the flood point gas velocity.

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