Tail gas treatment system and tail gas treatment method

Abstract

This application discloses an exhaust gas treatment system and method, belonging to the field of exhaust gas treatment technology. The exhaust gas treatment system includes an absorption component, a treatment component, and a regeneration component. The absorption component absorbs carbon dioxide and sulfur dioxide from the flue gas to produce a rich solution. The treatment component is connected to the absorption component and receives the rich solution from the absorption component, removing sulfate ions from the rich solution. The regeneration component is connected to the treatment component and thermally desorbs the sulfate-free rich solution to produce a lean solution. This application utilizes the absorption component to simultaneously absorb carbon dioxide and sulfur dioxide from the flue gas to generate a rich solution, and then uses the treatment component to pre-remove sulfate ions from the rich solution before thermal desorption. This effectively reduces the risk that sulfate will accumulate in the regeneration component due to its inability to be decomposed by heating, leading to a continuous decline in the treatment effect of the absorbent, thereby extending the service life of the absorbent.

Description

Technical Field

[0001] This application relates to the field of exhaust gas treatment technology, and in particular to an exhaust gas treatment system and exhaust gas treatment method. Background Technology

[0002] Marine carbon capture systems typically use organic amine solutions as absorbents, which react with carbon dioxide and sulfur dioxide in ship exhaust gases to achieve synergistic removal of these two acidic gases. However, after absorbing sulfur dioxide and carbon dioxide simultaneously, the organic amine absorbent generates stable sulfates, which are difficult to remove effectively using traditional heating regeneration methods, leading to a decrease in the absorbent's effectiveness in treating exhaust gases. Summary of the Invention

[0003] This application provides an exhaust gas treatment system and method to solve the technical problem of reduced treatment effect of absorbent on exhaust gas during the treatment of ship exhaust gas.

[0004] To achieve the above objectives, according to a first aspect of this application, an exhaust gas treatment system is provided, comprising: Absorption components are used to absorb carbon dioxide and sulfur dioxide from flue gas to produce rich liquid; A processing component is connected to the absorption component, the processing component being used to receive the rich solution delivered by the absorption component and remove sulfate ions from the rich solution; A regeneration component, connected to the processing component, is used to thermally desorb the rich solution after the removal of sulfate ions to produce a lean solution.

[0005] In some embodiments, the processing component includes: An exchange unit, connected to the absorption assembly, is used to receive the rich solution delivered by the absorption assembly and remove sulfate ions from the rich solution; A drug delivery unit, connected to the exchange unit, is used to provide an alkaline solution to the exchange unit to replace sulfate ions in the exchange unit.

[0006] In some embodiments, the exchange unit is provided with anion exchange resin, which exchanges ions with sulfate ions in the rich solution to remove sulfate ions from the rich solution.

[0007] In some embodiments, the exhaust gas treatment system further includes a monitoring component, the monitoring component comprising: The first detection unit is connected to the exchange unit and is used to detect the sulfate ion concentration in the exchange unit; A first valve body is disposed on the pipeline between the absorption assembly and the exchange unit; The control unit is electrically connected to the first detection unit and the first valve body, respectively; The control unit is configured to: when the sulfate ion concentration detected by the first detection unit reaches a first preset value, control the first valve to close, so that the absorption component stops supplying the rich solution to the exchange unit.

[0008] In some embodiments, the drug delivery unit has a drug delivery chamber and a waste liquid chamber, and the processing assembly further includes an inlet pipe and an outlet pipe, the inlet pipe being used to connect the drug delivery chamber to the exchange unit, and the outlet pipe being used to connect the waste liquid chamber to the exchange unit; The monitoring component further includes a second valve body and a third valve body electrically connected to the control unit, wherein the second valve body is disposed on the inlet pipe and the third valve body is disposed on the outlet pipe; The control unit is configured to: when the first valve is closed, control the second valve and the third valve to open, so that the drug delivery unit delivers alkaline solution to the exchange unit and discharges the waste liquid containing sulfate ions in the exchange unit through the outlet pipeline.

[0009] In some embodiments, the monitoring component further includes: The second detection unit is connected to the drug delivery unit and electrically connected to the control unit. The second detection unit is used to detect the liquid level of the alkaline solution in the drug delivery unit.

[0010] In some embodiments, the processing assembly further includes a replenishment line connected to the drug delivery unit for replenishing the drug delivery unit with alkali solution; The monitoring component also includes a fourth valve body, which is disposed on the medication pipeline and electrically connected to the control unit.

[0011] In some embodiments, the absorption component includes: An absorption section, connected to the exchange unit, is used to absorb carbon dioxide and sulfur dioxide in the flue gas to produce a rich liquid. The cooling section, connected to the absorption section, is used to cool the flue gas before it enters the absorption section.

[0012] In some embodiments, the processing component further includes: The heat exchange section has a rich liquid flow channel and a lean liquid flow channel; The inlet of the rich liquid flow channel is connected to the exchange unit for receiving the rich liquid output by the exchange unit, and the outlet of the rich liquid flow channel is connected to the regeneration component for supplying the preheated rich liquid to the regeneration component. The inlet of the lean liquid channel is connected to the regeneration component to receive the lean liquid output by the regeneration component, and the outlet of the lean liquid channel is connected to the absorption component to deliver the cooled lean liquid to the absorption component.

[0013] In some embodiments, the processing component further includes: A cooling section is provided on the pipeline between the heat exchange section and the absorption assembly, for further cooling of the lean liquid delivered from the outlet of the lean liquid channel to the absorption assembly.

[0014] In some embodiments, the regeneration component includes: The regeneration unit is connected to the processing assembly. The regeneration unit has a desorption zone and a washing zone. The washing zone is located on top of the desorption zone. The desorption zone is used to thermally desorb the rich solution to produce the lean solution. The washing zone is used to absorb the sulfur dioxide produced by the thermal desorption of the rich solution.

[0015] In some embodiments, the regeneration component further includes: A reboiling section, connected to the regeneration section, is used to heat the rich liquid within the regeneration section; A steam generator, connected to the reboiling section, is used to supply steam to the reboiling section.

[0016] According to a second aspect of this application, an exhaust gas treatment method is provided, applied to the aforementioned exhaust gas treatment system, the method comprising: Carbon dioxide and sulfur dioxide in the flue gas are absorbed by the absorption components to produce rich liquid; The rich solution is transported to a treatment unit, where sulfate ions are removed from the rich solution. The rich solution after sulfate ion removal is transported to a regeneration unit, where the rich solution after sulfate ion removal is thermally desorbed to produce a lean solution.

[0017] In some embodiments, the method further includes the step of regenerating the anion exchange resin: The concentration of sulfate ions within the exchange unit of the processing component is detected; When the detected sulfate ion concentration reaches a first preset value, the transfer of the rich solution from the absorption component to the exchange unit is stopped. An alkaline solution is delivered to the exchange unit through the drug delivery unit, causing the alkaline solution to replace sulfate ions in the anion exchange resin, and the waste liquid containing sulfate ions generated after the replacement is discharged from the exchange unit.

[0018] In some embodiments, the method further includes the step of replenishing the alkali solution: Detect the level of the alkaline solution within the drug delivery unit; When the detected level of the alkaline solution is lower than a second preset value, alkaline solution is added to the drug delivery unit.

[0019] The exhaust gas treatment system of this application includes an absorption component, a treatment component, and a regeneration component. The absorption component absorbs carbon dioxide and sulfur dioxide from the flue gas to produce a rich solution. The treatment component is connected to the absorption component and receives the rich solution from the absorption component, removing sulfate ions from the rich solution. The regeneration component is connected to the treatment component and thermally desorbs the sulfate-free rich solution to produce a lean solution. This application uses the absorption component to simultaneously absorb carbon dioxide and sulfur dioxide from the flue gas to generate a rich solution, and then uses the treatment component to pre-remove sulfate ions from the rich solution before thermal desorption. This effectively reduces the risk that sulfate will accumulate in the regeneration component due to its inability to be decomposed by heating, leading to a continuous decline in the treatment effect of the absorbent, thereby extending the service life of the absorbent. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0022] Figure 1 This is a schematic diagram of the exhaust gas treatment system provided in an exemplary embodiment of this disclosure; Figure 2 This is a schematic diagram of the exhaust gas treatment system provided in an exemplary embodiment of the present disclosure, including a monitoring component; Figure 3 This is a schematic diagram of the structure of the monitoring component provided in an exemplary embodiment of this disclosure; Figure 4 This is a schematic diagram of the structure of the processing component provided in an exemplary embodiment of this disclosure; Figure 5 This is a schematic diagram of the structure of the regeneration component provided in an exemplary embodiment of this disclosure; Figure 6 This is a flowchart of an exhaust gas treatment method provided in an exemplary embodiment of this disclosure.

[0023] Explanation of reference numerals in the attached figures: 10-Absorption assembly; 11-Absorption section; 12-Cooling section; 20-Processing assembly; 21-Exchange unit; 22-Dosage administration unit; 23-Inlet pipe; 24-Outlet pipe; 25-Replenishment pipe; 26-Cooling section; 27-Heat exchange section; 271-Rich liquid channel; 272-Lean liquid channel; 28-First pump; 29-Second pump; 30-Regeneration assembly; 31-Regeneration section; 311-Desorption zone; 312-Washing zone; 32-Reboiler section; 33-Steam generator section; 40-Monitoring assembly; 41-First detection section; 42-First valve body; 43-Control unit; 44-Second valve body; 45-Third valve body; 46-Second detection section; 47-Fourth valve body; 50-Fuel inlet pipe; 60-Collection unit; 70-Cooling water pipe. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0025] With the enactment of the International Maritime Organization's sulfur cap and increasingly stringent greenhouse gas emission regulations, ship exhaust gas treatment has become a focal point for the shipping industry. Marine carbon capture systems (CCS) and desulfurization systems have become important emission reduction methods due to their advantages, such as not requiring large-scale hull modifications and minimal impact on the ship's propulsion system. However, existing ship exhaust gas desulfurization and decarbonization systems are typically simple physical series connections of two independent units, resulting in large system space requirements and high construction and maintenance costs. More critically, while the organic amine solution used in the CCS can simultaneously absorb carbon dioxide and sulfur dioxide from the flue gas, the sulfates generated after sulfur dioxide absorption are stable and difficult to remove effectively from the absorbent using only traditional heating regeneration methods. This leads to continuous degradation of the amine solution and a sustained decline in absorption efficiency, severely impacting the long-term stable operation and economic viability of the system.

[0026] Please see Figure 1 This application provides an exhaust gas treatment system, including an absorption assembly 10, a treatment assembly 20, and a regeneration assembly 30. The absorption assembly 10 absorbs carbon dioxide and sulfur dioxide from the flue gas to produce a rich solution. The treatment assembly 20 is connected to the absorption assembly 10 and receives the rich solution from the absorption assembly 10, removing sulfate ions from the rich solution. The regeneration assembly 30 is connected to the treatment assembly 20 and thermally desorbs the sulfate-removed rich solution to produce a lean solution.

[0027] Specifically, the ship's exhaust gas first enters the absorption assembly 10 through the flue gas inlet pipe 50. The absorption assembly 10 is sprayed with organic amine absorbent, also known as lean solution. Carbon dioxide and sulfur dioxide in the flue gas are absorbed by the absorbent, forming a rich solution rich in carbonates, sulfites, and sulfates. This rich solution is then sent to the treatment assembly 20 for further treatment. The core function of the treatment assembly 20 is to selectively remove sulfate ions from the rich solution through ion exchange and other methods, targeting the stable sulfates generated after the organic amine absorbs sulfur dioxide. The sulfates do not enter the subsequent regeneration assembly 30 with the rich solution. The sulfate-free rich solution then enters the regeneration assembly 30, where thermal desorption decomposes the carbonates, releasing a high concentration of carbon dioxide gas. Simultaneously, the absorbent becomes lean solution again and is returned to the absorption assembly 10 for recycling.

[0028] This structure effectively reduces the risk of sulfate accumulation in the regeneration component 30, leading to a decrease in the treatment efficiency of the organic amine absorbent, by pre-removing sulfate ions before thermal desorption, thus significantly extending the service life of the organic amine absorbent. The lean solution produced by thermal desorption in the regeneration component 30 can be recycled back to the absorption component 10, achieving closed-loop utilization of the absorbent and reducing the maintenance cost of replacing the absorbent. Simultaneously, this structure integrates SO2 and CO2 removal functions into a single unit, reducing the problems of redundant infrastructure, large space occupation, and complex piping associated with traditional two independent systems connected in series. This improves the integration of the ship's flue gas treatment system and reduces the ship's space occupancy rate. Moreover, this system does not require open-loop desulfurization, thus avoiding the discharge of acidic wastewater and being environmentally friendly. Open-loop desulfurization refers to directly using the natural alkalinity of seawater to wash sulfur dioxide in ship exhaust gas. When the sulfur dioxide in the flue gas exceeds the buffer capacity of seawater, the unneutralized sulfur dioxide dissolves in the wash water, forming acidic wastewater.

[0029] Please see Figure 1 In some embodiments, the processing component 20 includes an exchange unit 21 and a drug delivery unit 22. The exchange unit 21 is connected to the absorption component 10 and is used to receive the rich solution delivered by the absorption component 10 and remove sulfate ions from the rich solution. The drug delivery unit 22 is connected to the exchange unit 21 and is used to provide an alkaline solution to the exchange unit 21 to displace sulfate ions in the exchange unit 21. A first pump 28 is provided in the pipeline between the absorption component 10 and the exchange unit 21 to provide driving force for the rich solution delivered from the absorption component 10 to the exchange unit 21.

[0030] Because the rich solution from the absorption assembly 10 contains a large amount of sulfate, which mainly originates from sulfur dioxide in the flue gas after being absorbed by organic amines, if these sulfates are directly introduced into the subsequent regeneration assembly 30, they are difficult to remove under thermal desorption conditions. Therefore, they gradually accumulate with the recycling of the absorbent, resulting in a higher and higher concentration and a gradual decrease in the treatment effect on the flue gas. In this embodiment, the rich solution first enters the exchange unit 21, which can be equipped with anion exchange resin. The anion exchange resin exchanges ions with the sulfate ions in the rich solution, thereby removing the sulfate ions and outputting a rich solution with a significantly reduced sulfate concentration.

[0031] By removing sulfate ions in advance before thermal desorption through the exchange unit 21, the risk of reduced efficiency in treating exhaust gas due to sulfate accumulation in the absorbent is effectively reduced, significantly extending the service life of the absorbent and reducing the frequency and cost of replacing the absorbent.

[0032] As operating time increases, the resin in exchange unit 21 will gradually reach sulfate adsorption saturation and lose its ability to remove sulfate. At this time, dosing unit 22 delivers an alkaline solution, such as a 5% to 10% sodium hydroxide solution, to exchange unit 21. The hydroxide ions in the alkaline solution can displace the sulfate ions adsorbed on the resin, restoring the resin's ion exchange capacity. At the same time, the sulfate-containing waste liquid generated by the displacement is discharged from the system.

[0033] Specifically, the rich solution delivered by the absorption assembly 10 to the exchange unit 21 contains a large number of protonated amine cations MEAH. + and sulfate anion SO4²⁻ - The rich solution flows through a strongly basic anion exchange resin at a certain flow rate. Within the resin bed, the following main ion exchange reaction occurs: ; In the formula, R represents the resin skeleton. Because the resin's selectivity for sulfate is much higher than its selectivity for hydroxide and other common anions, sulfate is preferentially adsorbed and firmly bound to the active functional groups of the resin. Simultaneously, hydroxide ions released from the resin enter the solution phase and undergo a transient neutralization reaction with protonated amine cations in the solution, as follows: ; Through this process, sulfate ions are removed from the amine solution, and the protonated amine is restored to its active free base form, thus achieving the chemical regeneration of the absorbent. When the resin reaches saturation in adsorbing sulfate ions, the sulfate purification stage terminates, and the process transitions to the resin regeneration stage.

[0034] The essence of resin regeneration is to reverse the aforementioned ion exchange equilibrium using a high-concentration regenerator (a strong base, such as NaOH), displacing the sulfate ions adsorbed on the resin and causing the resin to revert to its active group form (R-OH). The displacement reaction that occurs during the regeneration process is as follows: ; The displaced sulfate ions combine with sodium ions to form sodium sulfate (Na₂SO₄), which is discharged from the system along with the waste alkali solution. When the pH value and sulfate concentration of the discharged waste alkali solution are close to the level of the fresh regenerant, it indicates that the regeneration is basically complete.

[0035] Please see Figure 2 and Figure 3 In some embodiments, the exhaust gas treatment system further includes a monitoring component 40, which includes a first detection unit 41, a first valve body 42, and a control unit 43. The first detection unit 41 is connected to the exchange unit 21 and is used to detect the sulfate ion concentration within the exchange unit 21. The first valve body 42 is disposed on the pipeline between the absorption assembly 10 and the exchange unit 21. The control unit 43 is electrically connected to both the first detection unit 41 and the first valve body 42. The control unit 43 is configured to: when the sulfate ion concentration detected by the first detection unit 41 reaches a first preset value, control the first valve body 42 to close, so that the absorption assembly 10 stops supplying rich liquid to the exchange unit 21.

[0036] Specifically, during the continuous removal of sulfate ions from the rich solution, the anion exchange resin inside the exchange unit 21 gradually becomes saturated with sulfate ions. When the resin is close to saturation, the concentration of sulfate ions in the rich solution discharged from the outlet of the exchange unit 21 will increase significantly, meaning that the exchange unit 21 can no longer effectively remove sulfate ions. If the liquid feeding is not stopped in time, the rich solution with a high concentration of sulfate ions will directly enter the subsequent regeneration component 30, resulting in a reduction in the treatment effect of the organic amine absorbent liquid returning to the absorption component 10 on the exhaust gas. In this embodiment, the first detection unit 41 monitors the sulfate ion concentration in the exchange unit 21 in real time. The first detection unit 41 can be located on the outlet pipe of the exchange unit 21 or inside it. The first detection unit 41 can be a conductivity meter. When a significant increase in the conductivity of the liquid is detected, it indicates that the ion concentration in the liquid has increased, which also indicates that the concentration of sulfate ions in the liquid has increased. Moreover, the first detection unit 41 will transmit the conductivity signal to the control unit 43 in real time. The first detection unit 41 can also be a pH meter to detect the pH value in the liquid and then feed it back to the control unit 43.

[0037] The control unit 43 can be a central controller. The control unit 43 has a first preset value, which corresponds to the upper limit of the sulfate concentration allowed when the resin is close to saturation. When the detected concentration reaches or exceeds the preset value, the control unit 43 automatically issues a command to close the first valve 42 located between the absorption assembly 10 and the exchange unit 21, thereby cutting off the supply of rich liquid to the exchange unit 21.

[0038] This structure, through online detection and automatic control, can accurately determine the saturation state of the exchange unit 21, reducing the risks associated with the lag and uncertainty of manual judgment. It ensures timely cessation of liquid feeding before the exchange resin fails, preventing sulfate-rich solutions from entering subsequent processes and protecting the absorption efficiency of the organic amine absorbent. The automatic closing action of the first valve 42 achieves system self-protection, reducing the risk of overload operation of the exchange unit 21 and extending the service life of the anion exchange resin. Simultaneously, the monitoring component 40 eliminates the need for frequent manual sampling and testing, reducing the workload of operators and the risk of human error, and improving the system's automation level and operational stability. Furthermore, by timely stopping the liquid feeding, it provides an accurate start-up timing for the regeneration operation of the subsequent drug delivery unit 22, making the regeneration of the exchange unit 21 more efficient.

[0039] Please see Figure 2 and Figure 3 In some embodiments, the drug delivery unit 22 has a drug delivery chamber and a waste liquid chamber. The processing assembly 20 further includes an inlet pipe 23 and an outlet pipe 24. The inlet pipe 23 connects the drug delivery chamber to the exchange unit 21, and the outlet pipe 24 connects the waste liquid chamber to the exchange unit 21. The monitoring assembly 40 also includes a second valve body 44 and a third valve body 45 electrically connected to the control unit 43. The second valve body 44 is disposed on the inlet pipe 23, and the third valve body 45 is disposed on the outlet pipe 24. The inlet pipe 23 can be connected to the top of the exchange unit 21, allowing the alkaline solution to fully contact the exchange resin in the exchange unit 21 via spraying; alternatively, a turbulence structure can be provided within the exchange unit 21, allowing the alkaline solution entering the exchange unit 21 to fully contact the exchange resin under the action of the turbulence structure.

[0040] The control unit 43 is configured to control the second valve 44 and the third valve 45 to open when the first valve 42 is closed, so that the dosing unit 22 delivers alkaline solution to the exchange unit 21 and discharges the waste liquid containing sulfate ions in the exchange unit 21 through the outlet pipe 24.

[0041] Specifically, when the monitoring component 40 detects that the anion exchange resin in the exchange unit 21 has reached saturation, that is, when the sulfate ion concentration reaches the first preset value, and after the first valve 42 is closed, the control unit 43 automatically opens the second valve 44 and the third valve 45 to start the resin regeneration process. The alkaline solution (such as sodium hydroxide solution) stored in the drug delivery unit 22 enters the exchange unit 21 through the inlet pipe 23, displacing the sulfate ions adsorbed on the resin. The sulfate-containing waste liquid displaced is discharged into the waste liquid chamber for temporary storage through the outlet pipe 24 to avoid environmental pollution.

[0042] To further improve the utilization efficiency and regeneration effect of the alkali solution, this embodiment divides the drug delivery chamber into three independent sub-chambers, each connected to the exchange unit 21 via a corresponding pipeline (not shown in the figure). The three independent sub-chambers contain alkali solutions of 5%, 7%, and 10% concentrations, respectively. During regeneration, the 5% low-concentration alkali solution from the first sub-chamber first enters the exchange unit 21, initially replacing some of the sulfate ions in the resin. After the reaction, the alkali concentration further decreases and becomes waste liquid, which is discharged into the waste liquid chamber. Next, the 7% medium-concentration alkali solution from the second sub-chamber enters the exchange unit 21, further replacing the remaining sulfate ions. The alkali solution with reduced concentration after the reaction is not discharged but recycled back to the first sub-chamber as the initial low-concentration alkali solution for the next round of regeneration. Finally, the 10% high-concentration alkali solution from the third sub-chamber enters the exchange unit 21, completing the deep regeneration of the resin. The alkali solution with reduced concentration after the reaction is recycled back to the second sub-chamber. This forms a cyclical pattern of progressively increasing concentration and cascaded alkali solution reuse.

[0043] Taking 2 m³ of resin as an example, controlling the NaOH flow rate at 0.3 m³ / h and the total system flow rate for processing rich solutions at 10 m³ / h ensures that the regeneration process matches the system's processing requirements. This structure uses three sub-chambers with varying concentrations for stepwise regeneration, reducing the risk of alkali waste caused by direct contact between high-concentration alkali and saturated resin, while ensuring the resin is fully regenerated to its initial exchange capacity, extending its lifespan. Recycling the reduced-concentration alkali solution after the reaction into a lower-concentration sub-chamber for reuse significantly reduces the consumption of fresh alkali, lowering operating costs. Simultaneously, a dedicated waste liquid chamber stores sulfate-containing waste liquid, facilitating centralized subsequent treatment and avoiding environmental pollution caused by direct discharge. Furthermore, the automatic control unit 43 automatically controls the opening and closing sequence of each valve, achieving fully automated resin regeneration without manual intervention, improving system reliability and ease of operation.

[0044] Please see Figure 3 In some embodiments, the monitoring component 40 further includes a second detection unit 46. The second detection unit 46 is connected to the drug delivery unit 22 and electrically connected to the control unit 43. The second detection unit 46 is used to detect the level of the alkaline solution in the drug delivery unit 22.

[0045] Understandably, the alkali solution stored in the dosing unit 22 is a key material for regenerating the anion exchange resin in the exchange unit 21. With repeated regeneration operations, the alkali solution in the dosing unit 22 will gradually be consumed, and the liquid level will continuously decrease. If the alkali solution is depleted and not replenished in time, when the regeneration process needs to be restarted, it will be impossible to provide enough alkali solution to the exchange unit 21, resulting in the resin failing to regenerate and consequently affecting the continuous operation of the entire exhaust gas treatment system.

[0046] In this embodiment, the second detection unit 46 can be a liquid level sensor, a float switch, or an ultrasonic level gauge, which is installed on the drug delivery unit 22. It can detect the liquid level of the alkali solution in real time and transmit the liquid level signal to the control unit 43. The control unit 43 can make a judgment based on a preset low liquid level threshold. When the detected liquid level is lower than the threshold, the control unit 43 can issue an alarm signal, such as displaying a prompt message on the operation interface or triggering an audible and visual alarm, to remind the operator to replenish the alkali solution in time.

[0047] By monitoring the alkali level in the drug delivery unit 22 in real time through the second detection unit 46, the risk of regeneration failure due to alkali depletion can be reduced, ensuring that the exchange unit 21 always has regeneration conditions, thereby guaranteeing the continuous and stable operation of the entire exhaust gas treatment system. Simultaneously, the level detection signal is linked with the control unit 43, enabling automatic alarms or automatic replenishment when alkali is insufficient, eliminating the need for regular manual inspections and reducing the workload of operators and the risk of human error. Furthermore, the second detection unit 46 allows for more precise alkali management in the drug delivery unit 22, reducing both the risk of waste due to over-replenishment and the risk of system downtime due to untimely replenishment, thus improving the system's automation level and operational efficiency.

[0048] Please see Figure 3 In some embodiments, the processing component 20 further includes a replenishment line 25 connected to the drug delivery unit 22 for replenishing the drug delivery unit 22 with alkali solution. The monitoring component 40 also includes a fourth valve body 47 disposed on the replenishment line 25 and electrically connected to the control unit 43.

[0049] Because the alkali solution stored in the drug delivery unit 22 is gradually consumed after multiple regenerations of the anion exchange resin in the regeneration exchange unit 21, fresh alkali solution needs to be replenished to the drug delivery unit 22 periodically to maintain continuous system operation. In this embodiment, one end of the replenishment pipeline 25 is connected to an external alkali storage tank or an alkali supply system on a ship, and the other end is connected to the drug delivery unit 22. The fourth valve body 47 is installed on the replenishment pipeline 25 and electrically connected to the control unit 43 to achieve automatic control. When the second detection unit 46 detects that the alkali solution level in the drug delivery unit 22 is lower than a second preset value, the control unit 43 can automatically open the fourth valve body 47, allowing fresh alkali solution to flow into the drug delivery unit 22 through the replenishment pipeline 25 until the solution level returns to the preset high solution level. Then the control unit 43 closes the fourth valve body 47.

[0050] This structure, through the cooperation of the replenishment pipeline 25 and the fourth valve body 47, enables automatic replenishment of the alkali solution in the dosing unit 22, eliminating the need for frequent manual handling or addition of alkali solution and significantly reducing the labor intensity of operators. This automatic replenishment method reduces the risk of resin regeneration failure due to alkali depletion, ensuring that the exchange unit 21 can promptly restore its ion exchange capacity, thereby guaranteeing the long-term continuous and stable operation of the entire exhaust gas treatment system.

[0051] Please see Figure 1 In some embodiments, the absorption assembly 10 includes an absorption section 11 and a cooling section 12. The absorption section 11 is connected to the exchange unit 21 and is used to absorb carbon dioxide and sulfur dioxide in the flue gas to produce a rich liquid. The cooling section 12 is connected to the absorption section 11 and is used to cool the flue gas before it enters the absorption section 11.

[0052] Ship engine exhaust gases are typically at high temperatures, ranging from 200°C to 350°C. Organic amine absorbents are highly sensitive to flue gas temperature, with the optimal reaction temperature generally between 40°C and 60°C. If high-temperature flue gas directly enters the absorption section 11 and comes into contact with the organic amine absorbent, it will reduce the absorbency of the absorbent for carbon dioxide and sulfur dioxide. Furthermore, the high temperature may accelerate the thermal degradation of the organic amine absorbent, shortening its service life.

[0053] In this embodiment, the high-temperature flue gas first enters the cooling section 12, which can be cooled by seawater or fresh water, for example, by installing a heat exchanger or direct spray cooling, to reduce the flue gas temperature to a suitable absorption range. The cooled flue gas then enters the absorption section 11, where it comes into countercurrent contact with the organic amine absorbent sprayed from top to bottom. Carbon dioxide and sulfur dioxide in the flue gas are absorbed by the absorbent, generating a rich solution rich in carbonates, sulfites, and sulfates. The purified flue gas is discharged from the top of the absorption section 11. The rich solution generated in the absorption section 11 is then transported through pipelines to the exchange unit 21 for subsequent sulfate removal treatment. By setting the cooling section 12 before the absorption section 11, the flue gas temperature is controlled within the optimal reaction temperature range of the organic amine absorbent, significantly improving the removal efficiency of sulfur dioxide and carbon dioxide by the absorption section 11, reducing the risk of direct contact between the high-temperature flue gas and the organic amine absorbent, effectively reducing thermal degradation of the absorbent due to thermal stress, extending the service life of the organic amine absorbent, and reducing the cost of replacing the absorbent. Moreover, the cooling treatment allows the absorption section 11 to be made of conventional plastics or lined with corrosion-resistant materials, reducing the high-temperature resistance requirements of the materials and reducing equipment manufacturing costs.

[0054] Please see Figure 1 and Figure 4 In some embodiments, the processing component 20 further includes a heat exchange section 27, which has a rich liquid flow channel 271 and a lean liquid flow channel 272. The inlet of the rich liquid flow channel 271 is connected to the exchange unit 21 to receive the rich liquid output by the exchange unit 21, and the outlet of the rich liquid flow channel 271 is connected to the regeneration component 30 to supply preheated rich liquid to the regeneration component 30. The inlet of the lean liquid flow channel 272 is connected to the regeneration component 30 to receive the lean liquid output by the regeneration component 30, and the outlet of the lean liquid flow channel 272 is connected to the absorption component 10 to supply cooled lean liquid to the absorption component 10.

[0055] The rich solution output from the exchange unit 21 has had most of its sulfate ions removed. This rich solution has a low temperature, but requires a higher temperature, typically 100°C to 120°C, for thermal desorption in the regeneration assembly 30. Conversely, the lean solution output from the regeneration assembly 30 after thermal desorption regeneration has a higher temperature, but requires a lower temperature for spray absorption in the absorption assembly 10, with an optimal reaction temperature of 40°C to 60°C. Heating the rich solution and cooling the lean solution separately would consume a significant amount of additional thermal and cold energy. In this embodiment, the heat exchange section 27 can be a plate heat exchanger or a shell-and-tube heat exchanger. The heat exchange section 27 can integrate the rich solution channel 271 and the lean solution channel 272 into one unit, allowing heat exchange between the two without mixing. In operation, the lower-temperature rich solution flows through the rich solution channel 271, and the higher-temperature lean solution flows through the lean solution channel 272, transferring heat from the lean solution to the rich solution. The rich liquor is preheated before entering the regeneration unit 30, reducing the amount of heating required in the reboiling section 32 of the regeneration unit 30. The lean liquor is precooled before returning to the absorption unit 10, reducing the amount of cooling required in the cooling section 26.

[0056] This structure preheats the rich liquor by recovering waste heat from the lean liquor, significantly reducing the steam or electrical energy consumption required for the regeneration assembly 30 to heat the rich liquor, thus achieving cascaded utilization of heat within the system. The rich liquor, preheated before entering the regeneration assembly 30, reaches the required temperature for thermal desorption more quickly, shortening the heating time and improving regeneration efficiency. The lean liquor is pre-cooled during heat exchange, reducing the cooling load on the subsequent cooling section 26 and lowering the consumption of cooling medium. Furthermore, integrating heating and cooling functions into a single heat exchange section 27 reduces the number of devices and piping connections, lowering the system's space requirements and manufacturing costs.

[0057] Please see Figure 1 and Figure 4 In some embodiments, the processing assembly 20 further includes a cooling section 26. The cooling section 26 is disposed on the pipeline between the heat exchange section 27 and the absorption assembly 10, and is used to further cool the lean liquid delivered to the absorption assembly 10 from the outlet of the lean liquid channel 272.

[0058] The lean liquor output from the regeneration unit 30 has a reduced temperature after heat exchange in the heat exchange section 27. However, the heat exchange between the lean and rich liquors in the heat exchange section 27 cannot lower the lean liquor temperature to the ideal absorption range required, such as 40°C to 60°C. The temperature of the lean liquor after pre-cooling in the heat exchange section 27 may still be around 70°C to 80°C. If it is directly fed into the absorption unit 10, it will still adversely affect the absorption efficiency and thermal stability of the organic amine absorbent. Therefore, in this embodiment, a cooling section 26 is added to the pipeline between the heat exchange section 27 and the absorption unit 10. The cooling section 26 can be a seawater cooler or a freshwater cooler, utilizing readily available cooling media on the ship to perform secondary cooling of the lean liquor, controlling its temperature within the optimal reaction temperature range for the organic amine absorbent. After being cooled again by the cooling section 26, the lean liquor is finally transported to the top spray system of the absorption unit 10 to absorb carbon dioxide and sulfur dioxide from the newly entering flue gas. The cooling section 26 is connected to the cooling water pipe 70, and the cooling water pipe 70 provides cooling medium to the cooling section 26, thereby cooling the lean liquid delivered from the heat exchange section 27 to the cooling section 26.

[0059] The secondary cooling in the cooling section 26 ensures that the lean liquid temperature matches the optimal conditions for the absorption reaction in the subsequent absorption section 11, guaranteeing the efficient removal of carbon dioxide and sulfur dioxide from the flue gas by the absorption assembly 10. The lower-temperature lean liquid entering the absorption assembly 10 allows for more effective absorption of acidic gases in the flue gas, while reducing the loss of organic amine absorbent liquid due to evaporation at high temperatures.

[0060] Please see Figure 1 and Figure 5 In some embodiments, the regeneration assembly 30 includes a regeneration section 31. The regeneration section 31 is connected to the processing assembly 20. The regeneration section 31 has a desorption zone 311 and a washing zone 312. The washing zone 312 is disposed on top of the desorption zone 311. The desorption zone 311 is used to thermally desorb the rich solution to produce a lean solution. The washing zone 312 is used to absorb the sulfur dioxide produced by the thermal desorption of the rich solution.

[0061] The preheated rich solution, after passing through heat exchange section 27, enters desorption zone 311 from the upper part of regeneration section 31. Desorption zone 311 is equipped with packing or trays. The rich solution flows downwards under gravity, while reboiling section 32, connected to the bottom of regeneration section 31, heats the rich solution to the range required for carbonate decomposition in the organic amine absorbent, typically 100°C to 120°C. Under heating conditions, the carbonates in the rich solution undergo thermal desorption, releasing carbon dioxide gas. Simultaneously, the organic amine absorbent is restored to a lean solution and discharged from the bottom of regeneration section 31, then transported to heat exchange section 27. A second pump 29 is installed on the pipe between the bottom of regeneration section 31 and heat exchange section 27, providing driving force for the lean solution transported from regeneration section 31 to heat exchange section 27.

[0062] During desorption, a small amount of sulfite may remain in the rich solution. When heated, the sulfite decomposes to produce a small amount of sulfur dioxide gas, which escapes upwards along with carbon dioxide. If collected directly, the sulfur dioxide would contaminate the carbon dioxide, reducing its purity. Therefore, in this embodiment, a water washing zone 312 is provided at the top of the desorption zone 311. The gas rising from the desorption zone 311 (mainly carbon dioxide, containing a small amount of sulfur dioxide) enters the water washing zone 312. Fresh water or condensate is sprayed into the water washing zone 312. Sulfur dioxide is readily soluble in water and is washed and absorbed, thus being removed from the gas stream. The purity of the carbon dioxide gas after water washing is significantly improved. It is then discharged from the top of the regeneration section 31 and transported to the subsequent collection unit 60. The acidic aqueous solution formed after the water washing zone 312 absorbs sulfur dioxide can be discharged from the system or returned to the absorption assembly 10 for further processing.

[0063] Please see Figure 1 and Figure 5 In some embodiments, the regeneration assembly 30 further includes a reboiling section 32 and a steam generating section 33. The reboiling section 32 is connected to the regeneration section 31 and is used to heat the rich liquid in the regeneration section 31. The steam generating section 33 is connected to the reboiling section 32 and is used to supply steam to the reboiling section 32.

[0064] The rich liquid in the regeneration section 31 needs to be heated to a certain temperature to undergo thermal desorption, typically 100°C to 120°C, to release carbon dioxide and regenerate the organic amine absorbent. In this embodiment, the reboiling section 32 is connected to the bottom of the regeneration section 31 and can be a shell-and-tube heat exchanger, a plate heat exchanger, or a built-in heating coil. The steam generating section 33 can be a waste heat boiler on a ship, an electric steam generator, or an oil-fired boiler, etc., which can generate high-temperature steam and deliver it to the reboiling section 32. Inside the reboiling section 32, the high-temperature steam indirectly exchanges heat with the rich liquid at the bottom of the regeneration section 31. The steam condenses and releases heat, heating the rich liquid. Due to its reduced density, the heated rich liquid naturally circulates upwards, forming convection with the downstream rich liquid in the regeneration section 31, causing the temperature of the rich liquid in the entire regeneration section 31 to rise uniformly, promoting the decomposition of carbonates. The released carbon dioxide gas escapes upwards, and the regenerated lean liquid is discharged from the bottom. The condensed steam becomes condensate, which can be returned to the steam generating section 33 for reuse or discharged from the system.

[0065] Please see Figure 6 This application also provides an exhaust gas treatment method, applied to the above-mentioned exhaust gas treatment system, the method comprising: S1: Absorbs carbon dioxide and sulfur dioxide from flue gas through absorption component 10 to produce rich liquid.

[0066] S2: The rich solution is transported to the treatment unit 20, where sulfate ions are removed from the rich solution.

[0067] S3: The rich solution after removing sulfate ions is transported to the regeneration component 30, where the rich solution after removing sulfate ions is thermally desorbed to produce a lean solution.

[0068] The exhaust gas treatment method provided in this application first absorbs carbon dioxide and sulfur dioxide from the flue gas through an absorption assembly 10, producing a rich solution. This rich solution contains carbonates, sulfites, and sulfates generated by the absorption reaction. The rich solution is then transported to a treatment assembly 20, where anion exchange resin removes sulfate ions. This is because the sulfates generated after the organic amine absorbent absorbs sulfur dioxide are stable and, if directly introduced into the subsequent thermal desorption step, are difficult to decompose and accumulate, leading to a continuous decrease in the effectiveness of the organic amine absorbent. Therefore, it is necessary to remove sulfate ions beforehand. Finally, the sulfate-removed and preheated rich solution is transported to a regeneration assembly 30, where heating causes thermal desorption of the carbonates, releasing carbon dioxide. Simultaneously, the organic amine absorbent is regenerated into a lean solution and returned to the absorption assembly 10 for recycling.

[0069] The above three steps achieve the synergistic removal of sulfur dioxide and carbon dioxide in one system, eliminating the need for a large amount of repetitive equipment required by traditional two independent units connected in series, thus reducing ship space occupation and construction costs. At the same time, by removing sulfate ions before thermal desorption, the risk of organic amine absorbent liquid failing due to sulfate accumulation is effectively reduced, extending its service life and reducing maintenance expenses for replacing absorbent liquid.

[0070] The method also includes a step of regenerating the anion exchange resin. The anion exchange resin in the treatment assembly 20 gradually becomes saturated and loses its exchange capacity during the continuous removal of sulfate ions. Therefore, the method includes a first detection unit 41 that monitors the sulfate ion concentration in the exchange unit 21 in real time. When the detected concentration reaches a first preset value, the control unit 43 automatically closes the first valve 42, stopping the delivery of rich solution to the exchange unit 21, reducing the risk of unremoved sulfate solution entering subsequent processes. Subsequently, the dosing unit 22 delivers an alkaline solution, such as a 5%–10% sodium hydroxide solution, to the exchange unit 21. The hydroxide ions in the alkaline solution displace the sulfate ions adsorbed on the resin, restoring the resin's exchange capacity. The waste liquid containing sulfate ions generated from the displacement is discharged from the exchange unit 21 and temporarily stored in the waste liquid chamber. This regeneration step is automatically triggered by online concentration detection, avoiding the lag and uncertainty of manual judgment and ensuring timely regeneration of the resin when it becomes saturated.

[0071] The method also includes a step of replenishing the alkali solution. The alkali solution stored in the drug delivery unit 22 is continuously consumed after multiple resin regenerations, causing the liquid level to gradually decrease. If the alkali solution is depleted, subsequent resin regeneration cannot be completed, leading to system shutdown. Therefore, a second detection unit 46 is installed to monitor the alkali solution level in the drug delivery unit 22 in real time. When the detected liquid level is lower than a second preset value, the control unit 43 can issue an alarm signal to prompt the operator to replenish the alkali solution, or automatically open the fourth valve 47 to add fresh alkali solution to the drug delivery unit 22 through the replenishment pipeline 25 until the liquid level returns to normal. This step, through liquid level detection, monitors the alkali solution inventory and replenishes it as needed. This reduces both the risk of waste due to over-replenishment and the risk of regeneration failure due to insufficient alkali solution, ensuring long-term continuous and stable system operation.

[0072] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0073] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0074] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0075] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An exhaust gas treatment system, characterized in that, include: Absorption assembly (10) is used to absorb carbon dioxide and sulfur dioxide in flue gas to produce rich liquid; A processing component (20) is connected to the absorption component (10). The processing component (20) is used to receive the rich solution delivered by the absorption component (10) and remove sulfate ions from the rich solution. A regeneration component (30), connected to the processing component (20), is used to thermally desorb the rich solution after the removal of sulfate ions to produce a lean solution.

2. The exhaust gas treatment system according to claim 1, characterized in that, The processing component (20) includes: The exchange unit (21) is connected to the absorption assembly (10) and is used to receive the rich liquid delivered by the absorption assembly (10) and remove sulfate ions from the rich liquid; The drug delivery unit (22) is connected to the exchange unit (21) and is used to provide alkaline solution to the exchange unit (21) to replace sulfate ions in the exchange unit (21).

3. The exhaust gas treatment system according to claim 2, characterized in that, The exchange unit (21) is provided with anion exchange resin, which exchanges ions with sulfate ions in the rich solution to remove sulfate ions from the rich solution.

4. The exhaust gas treatment system according to claim 2, characterized in that, The exhaust gas treatment system further includes a monitoring component (40), which includes: The first detection unit (41) is connected to the exchange unit (21) and is used to detect the sulfate ion concentration in the exchange unit (21); The first valve body (42) is disposed on the pipeline between the absorption assembly (10) and the exchange unit (21); The control unit (43) is electrically connected to the first detection unit (41) and the first valve body (42), respectively; The control unit (43) is configured to: when the sulfate ion concentration detected by the first detection unit (41) reaches a first preset value, control the first valve body (42) to close, so that the absorption assembly (10) stops delivering the rich liquid to the exchange unit (21).

5. The exhaust gas treatment system according to claim 4, characterized in that, The drug delivery unit (22) has a drug delivery chamber and a waste liquid chamber. The processing assembly (20) further includes an inlet pipe (23) and an outlet pipe (24). The inlet pipe (23) is used to connect the drug delivery chamber to the exchange unit (21), and the outlet pipe (24) is used to connect the waste liquid chamber to the exchange unit (21). The monitoring component (40) further includes a second valve body (44) and a third valve body (45) electrically connected to the control unit (43). The second valve body (44) is disposed on the inlet pipe (23), and the third valve body (45) is disposed on the outlet pipe (24). The control unit (43) is configured to: when the first valve body (42) is closed, control the second valve body (44) and the third valve body (45) to open, so that the drug delivery unit (22) delivers alkaline solution to the exchange unit (21) and discharges the waste liquid containing sulfate ions in the exchange unit (21) through the outlet pipe (24).

6. The exhaust gas treatment system according to claim 4, characterized in that, The monitoring component (40) also includes: The second detection unit (46) is connected to the drug delivery unit (22) and electrically connected to the control unit (43). The second detection unit (46) is used to detect the level of alkaline solution in the drug delivery unit (22).

7. The exhaust gas treatment system according to claim 6, characterized in that, The processing component (20) also includes a drug replenishment line (25), which is connected to the drug delivery unit (22) and is used to replenish the drug delivery unit (22) with alkali solution; The monitoring component (40) also includes a fourth valve body (47), which is disposed on the drug supply line (25) and electrically connected to the control unit (43).

8. The exhaust gas treatment system according to claim 2, characterized in that, The absorption component (10) includes: An absorption section (11) is connected to the exchange unit (21). The absorption section (11) is used to absorb carbon dioxide and sulfur dioxide in the flue gas to produce a rich liquid. The cooling section (12) is connected to the absorption section (11) and is used to cool the flue gas before it enters the absorption section (11).

9. The exhaust gas treatment system according to claim 2, characterized in that, The processing component (20) further includes: The heat exchange section (27) has a rich liquid flow channel (271) and a lean liquid flow channel (272). The inlet of the rich liquid flow channel (271) is connected to the exchange unit (21) for receiving the rich liquid output by the exchange unit (21), and the outlet of the rich liquid flow channel (271) is connected to the regeneration component (30) for supplying the preheated rich liquid to the regeneration component (30). The inlet of the lean liquid channel (272) is connected to the regeneration component (30) for receiving the lean liquid output by the regeneration component (30), and the outlet of the lean liquid channel (272) is connected to the absorption component (10) for delivering the cooled lean liquid to the absorption component (10).

10. The exhaust gas treatment system according to claim 9, characterized in that, The processing component (20) further includes: A cooling section (26) is provided on the pipeline between the heat exchange section (27) and the absorption assembly (10) for further cooling of the lean liquid delivered to the absorption assembly (10) from the outlet of the lean liquid channel (272).

11. The exhaust gas treatment system according to claim 1, characterized in that, The regeneration component (30) includes: The regeneration unit (31) is connected to the processing assembly (20). The regeneration unit (31) has a desorption zone (311) and a washing zone (312). The washing zone (312) is located on top of the desorption zone (311). The desorption zone (311) is used to thermally desorb the rich liquid to produce the lean liquid. The washing zone (312) is used to absorb the sulfur dioxide produced by the thermal desorption of the rich liquid.

12. The exhaust gas treatment system according to claim 11, characterized in that, The regeneration component (30) also includes: The reboiling section (32) is connected to the regeneration section (31) and is used to heat the rich liquid in the regeneration section (31); A steam generator (33) is connected to the reboiling section (32) and is used to supply steam to the reboiling section (32).

13. A method for treating exhaust gas, characterized in that, The method, applied to the exhaust gas treatment system as described in any one of claims 1 to 12, comprises: Carbon dioxide and sulfur dioxide in the flue gas are absorbed by the absorption assembly (10) to produce a rich liquid; The rich solution is transported to the processing unit (20), where sulfate ions are removed from the rich solution; The rich solution after sulfate ion removal is transported to the regeneration unit (30), where the rich solution after sulfate ion removal is thermally desorbed to produce a lean solution.

14. The exhaust gas treatment method according to claim 13, characterized in that, The method further includes a regeneration step: The concentration of sulfate ions in the exchange unit (21) of the processing component (20) is detected; When the detected sulfate ion concentration reaches a first preset value, the transfer of the rich solution from the absorption component (10) to the exchange unit (21) is stopped. Alkali solution is delivered to the exchange unit (21) through the drug delivery unit (22), so that the alkali solution replaces the sulfate ions in the anion exchange resin, and the waste liquid containing sulfate ions generated after replacement is discharged from the exchange unit (21).

15. The exhaust gas treatment method according to claim 14, characterized in that, The method also includes the step of replenishing the alkali solution: Detect the level of alkaline solution in the drug delivery unit (22); When the detected level of the alkaline solution is lower than the second preset value, the alkaline solution is replenished to the drug delivery unit (22).

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