Modularized vacuum pressure swing adsorption FPSO carbon dioxide capture method

Abstract

The invention relates to the technical field of carbon dioxide capture, in particular to a modular FPSO (vacuum pressure swing adsorption) carbon dioxide capture method, and provides a capture device which comprises a pretreatment unit, an adsorption unit, a storage unit and a control unit. Setting a control model in a control unit, outputting a control rate, an optimal adsorption parameter, an optimal analysis parameter and a voltage-sharing period parameter through the control model, and feeding back the control rate, the optimal adsorption parameter, the optimal analysis parameter and the voltage-sharing period parameter to an actuator of the control unit, so that the actuator controls a preprocessing unit, an adsorption unit and a storage unit to operate; flue gas is cooled, compressed and dried through the pretreatment unit, CO2 in the flue gas is adsorbed and desorbed through the adsorption unit, and CO2 desorbed by the adsorption unit is stored in the storage and collection unit. According to the invention, the capture efficiency and capture safety of carbon dioxide are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to a modular vacuum pressure swing adsorption FPSO carbon dioxide capture method. Background Art

[0002] Floating production, storage and offloading (FPSO) vessels, with their unique integrated design and operational model, present numerous technical challenges in terms of space utilization and energy consumption. Compared to onshore oil and gas production facilities, FPSOs have limited deck space, requiring highly integrated equipment and a layout that considers the complexity of the marine environment and operational safety. Furthermore, the FPSO's power supply system must meet even more stringent requirements to ensure equipment safety and production efficiency while minimizing energy consumption. Therefore, the application of traditional CO2 capture technology on FPSOs has certain limitations, necessitating the development of more adaptable technical solutions. Summary of the Invention

[0003] The present invention aims to address at least one of the technical problems existing in the related art. To this end, the present invention provides a modular vacuum pressure swing adsorption (VPA) FPSO carbon dioxide capture method, which addresses the existing technical issues of difficult and operational FPSO carbon dioxide capture, thereby improving both the efficiency and safety of carbon dioxide capture.

[0004] The present invention provides a modular vacuum pressure swing adsorption FPSO carbon dioxide capture method, comprising the following steps: Providing a capture device, the capture device comprising a pretreatment unit, an adsorption unit, a storage unit and a control unit; A control model is set in the control unit, and a control rate, an optimal adsorption parameter, an optimal analytical parameter, and a pressure equalization cycle parameter are outputted by the control model and fed back to an actuator of the control unit, so that the actuator controls the operation of the pretreatment unit, the adsorption unit, and the reservoir unit; The flue gas is cooled, compressed and dried by the pretreatment unit, and CO2 in the flue gas is adsorbed and desorbed by the adsorption unit. The CO2 desorbed by the adsorption unit is stored in the storage unit.

[0005] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the pretreatment unit includes a raw gas precooler, a flue gas gas-liquid separator, a raw gas compressor, a raw gas cold dryer and a cold dryer gas-liquid separator, and the raw gas compressor is provided with a cooler; When the flue gas is cooled, compressed and dried by the pretreatment unit, the following steps are included: The flue gas first enters the raw gas precooler, which reduces the temperature of the flue gas from 200~250℃ to 60~100℃. The cooled flue gas flows into the flue gas-liquid separator to separate the first batch of condensate. Then the flue gas passes through the raw gas compressor to increase the pressure of the flue gas and cools it down through the cooler. The flue gas then enters the raw gas dryer for drying. The dried flue gas passes through the dryer gas-liquid separator to separate the second batch of condensate. Then the flue gas enters the adsorption unit.

[0006] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the pressure of the flue gas is increased to greater than or equal to 0.4 MPa by a raw gas compressor.

[0007] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the temperature of the flue gas is reduced to below 50° C. by the cooler.

[0008] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the adsorption unit includes a plurality of adsorption towers, a vacuum pump and a clean gas buffer tank; When the adsorption unit is used to adsorb and desorb CO2 in the flue gas, the following steps are included: The flue gas pretreated by the pretreatment unit enters the adsorption tower, and the adsorbent in the adsorption tower adsorbs CO2 to separate CO2 from the flue gas. When the adsorbent reaches saturation, the adsorption tower is desorbed by a vacuum pump to allow the adsorbent in the adsorption tower to desorb CO2. The clean gas in the clean gas buffer tank is filled into the adsorption tower through the vacuum pump, so that the adsorption tower is re-pressurized and recycled.

[0009] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the storage unit includes a CO2 compressor, a condenser, and a liquefied storage tank; The CO2 desorbed from the adsorption tower is compressed by a CO2 compressor, and the compressed gaseous CO2 is converted into liquid CO2. The liquid CO2 enters the condenser for cooling and then enters the liquefied storage tank for storage.

[0010] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the control model adopts a model predictive control framework, and the control rate in the model predictive control framework is: in, For The system state vector at time t, For The system output vector at time t, For The control input of the time system, exist The external disturbance of the system at the moment, is the state transition parameter, To control the input parameters, is the disturbance input parameter, is an output parameter, Is to pass parameters directly; according to and setting goals , obtain the optimal control input sequence by minimizing the objective function and constraint function; Minimum objective function: Constraint function: in, is the time variation amplitude, is the number of time steps for prediction, is the output error weight parameter, To control the input variation parameters, To control the minimum constraint of the sequence, is the maximum constraint of the control sequence, is the minimum constraint of the system state vector, is the maximum constraint of the system state vector; The minimum objective function and constraint function will be satisfied It is sent to the actuator as the optimal control input sequence.

[0011] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the control model also constructs a dual-objective optimization model : in, The capture device runs from the set time to the The accumulated energy consumption at the time, is the CO2 capture efficiency; The optimal adsorption parameters, optimal analytical parameters and pressure equalization cycle parameters are determined according to the dual-objective optimization model to achieve dynamic adjustment.

[0012] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the capture device further includes a plurality of sensors for monitoring the pretreatment unit, the adsorption unit and the storage unit. The sensors collect data and transmit it to the control unit in real time. The control unit is provided with an alarm module. The alarm calculation model in the alarm module is: in, For real-time measurement data, is the abnormal parameter of the capture system; when When the preset threshold is exceeded, the control center issues an early warning.

[0013] A further improvement of the modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention is that the alarm module is provided with a multi-level early warning mechanism. Multi-level early warning mechanism for: in, , is the first alarm threshold, is the second alarm threshold, is the third alarm threshold, First alarm level, Second alarm level, It is the third alarm level; The alarm module automatically triggers the corresponding alarm level according to the multi-level early warning mechanism and initiates emergency response operations, including adjusting operating parameters, switching to backup equipment, or performing emergency shutdowns to ensure stable operation of the system; When triggered When the alarm module is activated, it will automatically record the alarm log and back up the parameter data; When triggered When , the alarm module will perform the parameter adjustment operation; When triggered When the alarm is triggered, the alarm module will switch to the backup device or perform an emergency shutdown.

[0014] The present invention effectively removes impurities and moisture from the flue gas through the pretreatment process of the pretreatment unit, avoiding their interference with the adsorbent, and can significantly improve the adsorption efficiency of the subsequent adsorption unit for CO2, extend the service life of the adsorbent, and reduce operating costs. The control model set in the control unit can dynamically adjust the control rate, optimal adsorption parameters, optimal analysis parameters and pressure equalization cycle parameters according to real-time data, thereby realizing the intelligence and automation of the capture process, improving the capture efficiency, ensuring the stability and reliability of the capture process, and reducing the risk of manual intervention and misoperation. The adsorption unit adopts a high-efficiency adsorbent to selectively adsorb CO2 in the flue gas, thereby realizing efficient and environmentally friendly CO2 capture. The desorption operation can release the adsorbed CO2 and store it in the storage unit, which provides convenience for subsequent processing and utilization. The capture device has the advantages of high efficiency, stability, and environmental protection. It can significantly reduce the emission of CO2 in the flue gas and improve the utilization of CO2. It is of great significance to promote energy conservation, emission reduction and sustainable development.

[0015] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a schematic diagram of a modular vacuum pressure swing adsorption FPSO carbon dioxide capture method provided by the present invention.

[0018] Figure 2 This is a schematic diagram of a modular vacuum pressure swing adsorption FPSO carbon dioxide capture device provided by the present invention.

[0019] Reference numerals: 1. Primary vacuum pump; 2. Raw gas compressor; 3. CO2 compressor; 4. Secondary vacuum pump; 5. Raw gas cold dryer; 6. Primary desorption gas buffer tank; 7. Primary reverse venting buffer tank; 8. Cold dryer gas-liquid separator; 9. Raw gas precooler; 10. Flue gas gas-liquid separator; 11. Primary adsorption tower; 12. Secondary adsorption tower; 13. Secondary air intake tower; 14. Secondary reverse venting buffer tank; 15. Secondary clean gas buffer tank; 16. Secondary desorption gas buffer tank. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0021] The following combination Figure 1 and Figure 2 The present invention describes a modular vacuum pressure swing adsorption FPSO carbon dioxide capture method, comprising the following steps: Providing a capture device, the capture device comprising a pretreatment unit, an adsorption unit, a storage unit and a control unit; A control model is set in the control unit, and the control model outputs a control rate, an optimal adsorption parameter, an optimal analytical parameter, and a pressure equalization cycle parameter and feeds them back to the actuator of the control unit, so that the actuator controls the operation of the pretreatment unit, the adsorption unit, and the reservoir unit; The flue gas is cooled, compressed and dried through the pretreatment unit, and the CO2 in the flue gas is adsorbed and desorbed through the adsorption unit. The CO2 desorbed by the adsorption unit is stored in the storage unit.

[0022] In a preferred embodiment of a modular vacuum pressure swing adsorption FPSO carbon dioxide capture method of the present invention, the pretreatment unit includes a raw gas precooler 9, a flue gas gas-liquid separator 10, a raw gas compressor 2, a raw gas cold dryer 5 and a cold dryer gas-liquid separator 8, and the raw gas compressor 2 is provided with a cooler; the flue gas first enters the raw gas precooler 9, and the temperature of the flue gas is reduced from 200~250℃ to 60~100℃. The cooled flue gas flows into the flue gas gas-liquid separator 10 to separate the first batch of condensate. Then, the flue gas passes through the raw gas compressor 2 to increase the flue gas pressure to greater than or equal to 0.4MPa, and is cooled to below 50℃ by the cooler. Then, the flue gas enters the raw gas cold dryer 5 for drying. The dried flue gas passes through the cold dryer gas-liquid separator 8 to separate the second batch of condensate, and then the flue gas enters the adsorption unit.

[0023] Preferably, the first batch of condensate and the second batch of condensate can be discharged into the ocean after undergoing wastewater treatment procedures.

[0024] The raw gas precooler adopts efficient heat exchange technology, which can quickly and evenly reduce the temperature of the flue gas, ensuring that it reaches the appropriate temperature range before entering the subsequent processing steps. The flue gas liquid separator 10 can effectively separate the liquid components in the flue gas to prevent it from causing adverse effects on subsequent equipment. The raw gas compressor 2 is equipped with advanced compression technology and sealing devices, which can greatly increase the pressure of the flue gas while reducing energy loss and leakage risks. The cooler further reduces the temperature of the flue gas at the outlet of the raw gas compressor to ensure that it is within a safe and stable operating range. The raw gas cold dryer 5 can quickly absorb and remove moisture from the flue gas, ensuring that the flue gas entering the adsorption unit is dry and pure. The cold dryer gas-liquid separator 8 separates the flue gas again to ensure that the flue gas entering the adsorption unit is completely free of liquid components, thereby further improving the adsorption efficiency and capture quality.

[0025] Furthermore, the adsorption unit includes multiple adsorption towers, a vacuum pump and a clean gas buffer tank; the flue gas pretreated by the pretreatment unit enters the adsorption tower, and the adsorbent in the adsorption tower adsorbs CO2 to separate CO2 from the flue gas. When the adsorbent reaches saturation, the adsorption tower is desorbed by the vacuum pump so that the adsorbent in the adsorption tower desorbs CO2, and the clean gas in the clean gas buffer tank is filled into the adsorption tower through the vacuum pump, so that the adsorption tower is re-pressurized and recycled.

[0026] Specifically, the adsorption unit includes a first-level adsorption device and a second-level adsorption device; the first-level adsorption equipment includes 10 first-level adsorption towers 11, 2 first-level vacuum pumps 1, 1 first-level desorption gas buffer tank 6 and 1 first-level reverse degassing buffer tank 7; the second-level adsorption equipment includes 5 second-level adsorption towers 12, 1 second-level air intake tower 13, 1 second-level vacuum pump 4, 1 second-level reverse degassing buffer tank 14, 1 second-level clean gas buffer tank 15 and 1 second-level desorption gas buffer tank 16.

[0027] The pretreated flue gas enters the primary adsorption tower 11 from the bottom of the primary adsorption tower 11. The primary adsorption tower 11 operates at a pressure of 0.4 MPa. The adsorbent adsorbs CO2 in the flue gas, increasing the CO2 concentration from about 5% to more than 30%. When the adsorbent is close to saturation, the primary adsorption tower 11 performs two equalization pressure reduction and vacuum desorption operations through the primary vacuum pump 1. The primary adsorption tower 11 is vacuumed under the action of the primary vacuum pump 1 to desorb the CO2 on the adsorbent and enter the primary desorption gas buffer tank 6. The primary adsorption tower 11 performs equalization pressure boosting through the pretreated flue gas and gradually restores the working pressure. The gas in the first-level desorption gas buffer tank 6 enters the second-level air inlet tower 13 through the first-level reverse venting buffer tank 7, and then enters the second-level adsorption tower 12. The second-level adsorption tower 12 operates at a pressure of 0.4 MPa, and the adsorbent adsorbs CO2, increasing the CO2 concentration from about 5% to more than 30%; when the adsorbent is close to saturation, the second-level adsorption tower 12 performs two equalization pressure reduction and vacuum desorption operations through the second-level vacuum pump 4. The second-level adsorption tower 12 performs a vacuum operation under the action of the second-level vacuum pump 4 to desorb the CO2 on the adsorbent and enter the second-level desorption gas buffer tank 16. The clean gas in the second-level clean gas buffer tank 15 enters the second-level adsorption tower 12 to perform two equalization pressure increases on the second-level adsorption tower 12, and gradually restores the working pressure. The CO2 in the second-level desorption gas buffer tank 16 enters the storage unit through the second-level reverse venting buffer tank 14 for storage.

[0028] The control unit automatically adjusts the adsorption and desorption cycles based on the adsorbent's saturation state and the overall needs of the capture device to achieve efficient CO2 capture. During the desorption process, the vacuum pump creates a sufficient negative pressure to effectively release the CO2 from the adsorbent while avoiding any secondary contamination that may occur during the desorption process. The clean gas buffer tank stores deeply purified gas, which is then charged into the adsorption tower after desorption. This not only aids in adsorbent regeneration but also ensures the continuous and stable operation of the entire capture device.

[0029] Furthermore, the storage unit includes a CO2 compressor 3, a condenser, and a liquefied storage tank; the CO2 desorbed from the adsorption tower is compressed by the CO2 compressor 3, and the compressed gaseous CO2 is converted into liquid CO2. The liquid CO2 enters the condenser for cooling and then enters the liquefied storage tank for storage.

[0030] The liquefied gas storage tanks offer excellent thermal insulation, effectively maintaining the low temperature of the liquid CO2 and preventing it from re-gasifying due to rising ambient temperatures. The control system automatically adjusts the operating frequency of the CO2 compressor and the cooling intensity of the condenser based on the liquid level in the liquefied gas storage tanks to ensure stable storage and efficient management of the liquid CO2. The entire storage unit is designed with safety and reliability in mind, ensuring the efficiency and continuity of the CO2 capture process.

[0031] Furthermore, the control model adopts the model predictive control framework, and the control rate in the model predictive control framework is: in, For The system state vector at time t, For The system output vector at time t, For The control input of the time system, exist The external disturbance of the system at the moment, is the state transition parameter, To control the input parameters, is the disturbance input parameter, is an output parameter, Is to pass parameters directly; according to and setting goals , obtain the optimal control input sequence by minimizing the objective function and constraint function; Minimum objective function: Constraint function: in, is the time variation amplitude, is the number of time steps for prediction, is the output error weight parameter, To control the input variation parameters, To control the minimum constraint of the sequence, is the maximum constraint of the control sequence, is the minimum constraint of the system state vector, is the maximum constraint of the system state vector; The minimum objective function and constraint function will be satisfied It is sent to the actuator as the optimal control input sequence.

[0032] This control model achieves optimal CO2 capture by predicting the future state of the capture unit in real time and adjusting the control inputs based on the predictions. During implementation, the system state vector, output vector, control inputs, and external disturbance parameters are first determined based on the actual conditions of the CO2 capture unit on the FPSO. The model predictive control framework is then used to calculate the optimal control inputs under given constraints. Through continuous iteration and optimization, the control model can adjust the adsorption tower's operating pressure, temperature, and adsorbent regeneration conditions in real time, ensuring that the CO2 capture unit always operates in its optimal state. Furthermore, the control model exhibits a certain degree of robustness, enabling it to cope with complex and changing environmental conditions at sea and ensure the stable operation of the CO2 capture system on the FPSO.

[0033] After receiving the optimal control input sequence, the actuators precisely control the system according to the instructions contained in the optimal control input sequence. During this process, the control unit dynamically adjusts the adsorption and desorption processes based on current CO2 concentration, pressure, and temperature, ensuring that CO2 capture efficiency remains high throughout the FPSO's operating life.

[0034] Based on the optimal control input sequence it receives, the actuator precisely controls each module in the vacuum pressure swing adsorption system. This includes adjusting the operating pressure and temperature of the adsorption module, as well as the adsorbent regeneration conditions, to ensure efficient CO2 capture. Simultaneously, the system uses sensors to monitor the operating status of each module in real time, such as key parameters like pressure, temperature, and flow rate, and feeds this real-time data back to the control model. Based on this feedback, the control model fine-tunes the optimal control input sequence to accommodate various possible operating conditions. This closed-loop control strategy not only improves the stability and reliability of the capture device, but also further enhances the accuracy and efficiency of CO2 capture.

[0035] Furthermore, the control model also constructs a dual-objective optimization model : in, The capture device runs from the set time to the The accumulated energy consumption at the time, is the CO2 capture efficiency; The optimal adsorption parameters, optimal analytical parameters and pressure equalization cycle parameters are determined according to the dual-objective optimization model to achieve dynamic adjustment.

[0036] This dual-objective optimization model comprehensively considers the balance between energy consumption and capture efficiency, aiming to find the optimal combination of operating parameters that ensures efficient CO2 capture while minimizing energy consumption. Using precise mathematical models and algorithms, the control model analyzes and predicts energy consumption and capture efficiency under different parameters in real time, thereby determining the optimal operating strategy.

[0037] Preferably, the state transfer parameter, control input parameter, disturbance input parameter, output parameter, direct transfer parameter, output error weight parameter, and control input variation parameter are all fixed parameters in the control model, and their values are: state transfer parameter , control input parameters , disturbance input parameter , output parameters , pass parameters directly , output error weight parameter , control input change parameter .

[0038] In a specific embodiment, the system state vector is used to describe the internal state of the system. ,in, Indicates the CO2 concentration in the adsorption tower, represents the adsorption tower pressure, represents the temperature of the adsorbent; The system output vector is used to describe the measurable output of the system. ,in, Indicates the CO2 capture efficiency, Represents the net flue gas flow; the control input of the system is used to describe the adjustable control input, ,in, Indicates the set pressure of the adsorption tower. Indicates the vacuum intensity set by the vacuum pump; the external disturbance of the system is used to indicate the initial concentration of CO2 in the flue gas entering the system; State transfer parameters, control input parameters, disturbance input parameters, output parameters, and direct transfer parameters are ; The number of predicted time steps is 10, and the output error weight parameter is , control input change parameter , the minimum constraint of the control sequence , control sequence maximum constraint ， Minimum constraint on system state vector , the maximum constraint of the system state vector ， Set goals ; Objective function ,in, Indicates The output error term at time , Indicates Control change item at the moment; ,in, Indicates the change value of the control input; The specific steps are: Setting initial conditions ; Predicting state evolution ; Calculation example: ; Calculate the objective function: ; Assumption , , Output error term Control changes Constraint handling: 0.35≤5.38≥0.6 does not satisfy the constraint function; Then continue to calculate , Finally, the minimum objective function is The weighted sum of squares of all output error terms plus The weighted sum of squares of all control variations in .

[0039] Regarding the optimal parameter selection, as mentioned above, the selection is made by comparing the performance of the closed-loop system under different parameters (such as overshoot, steady-state error, constraint violation, etc.).

[0040] The constraint function that will satisfy the minimum objective function is sent to the actuator as the optimal control input sequence.

[0041] Optimal control input sequence for: The parameter setting process is shown in Table 1: Table 1 Note: The weight ratio is set as energy consumption: efficiency = 0.6:0.4.

[0042] The control model calculates the corresponding ,choose The smallest parameter group is taken as the optimal parameter; when the weight needs to be adjusted to focus on energy consumption or efficiency, recalculate ; The parameter range is dynamically adjusted through network search and real-time adjustment is made to meet the changes in working conditions.

[0043] Under the working conditions in Table 1, group 1 corresponding to the minimum value (adsorption pressure of 0.40 MPa, desorption pressure of 0.05 MPa, and pressure equalization period of 10 min) was selected as the optimal adsorption parameter, optimal desorption parameter, and pressure equalization period parameter.

[0044] Since the initial state and disturbance are unknown, the control rate depends on the specific scenario and is generally in the form of ,in Changes in 0.35~0.6MPa to track the pressure, The pressure can be changed between 20 and 100 kPa to adjust the vacuum.

[0045] Under the optimal parameters (adsorption pressure of 0.40MPa, desorption pressure of 0.05MPa), the control rate may be biased towards the adsorption stage. ≈0.40, ≈0, parsing stage ≈0.05, ≈80, but needs to be optimized.

[0046] The above numerical examples clarify the definitions of state, output, control input and disturbance in the control model, provide specific matrix parameters and constraints, and clearly describe the solution process of the optimal control input sequence.

[0047] Specifically, the capture device also includes several sensors, which are used to monitor the pretreatment unit, the adsorption unit and the storage unit. The sensors collect data and transmit it to the control unit in real time. The control unit is provided with an alarm module. The alarm calculation model in the alarm module is: in, For real-time measurement data, is the abnormal parameter of the capture system; when When the preset threshold is exceeded, the control center issues an early warning.

[0048] These sensors cover key operating parameters such as temperature, pressure, flow, and gas concentration, ensuring that every detail of the system's operation is accurately monitored. Once the sensor detects any abnormal data, such as an abnormal increase in the inlet temperature of the pretreatment unit or an excessive CO2 concentration at the outlet of the adsorption unit, these real-time measurement data will be immediately transmitted to the control unit. The alarm calculation model within the control unit will quickly analyze this data and compare it with the preset abnormal parameter thresholds. If the measurement data exceeds the preset safety range, the alarm module will immediately trigger the early warning mechanism. The control center will receive the alarm signal and immediately take countermeasures, such as adjusting operating parameters, starting backup equipment, or performing an emergency shutdown to prevent potential safety accidents and ensure the stable and safe operation of the capture system.

[0049] Specifically, the alarm module is equipped with a multi-level early warning mechanism. Multi-level early warning mechanism for: in, , is the first alarm threshold, is the second alarm threshold, is the third alarm threshold, First alarm level, Second alarm level, It is the third alarm level; The alarm module automatically triggers the corresponding alarm level according to the multi-level early warning mechanism and initiates emergency response operations, including adjusting operating parameters, switching to backup equipment, or performing emergency shutdowns to ensure stable system operation; When triggered When the alarm module is turned on, it will automatically record the alarm log and back up the parameter data; When triggered When the alarm module performs parameter adjustment operations; When triggered When the alarm is triggered, the alarm module will switch to the backup device or perform an emergency shutdown.

[0050] Preferably, the first alarm threshold is set when the carbon dioxide concentration reaches 80% of the upper safety limit, the second alarm threshold is set when it reaches 90% of the upper safety limit, and the third alarm threshold is set when it exceeds the upper safety limit. The first alarm level is a primary warning, the second alarm level is a medium warning, and the third alarm level is a high warning.

[0051] When a primary warning is triggered, the alarm module automatically records the alarm log and backs up the current system operating parameter data for subsequent analysis and troubleshooting. This step ensures data integrity and traceability, providing an important basis for troubleshooting.

[0052] When an intermediate warning is triggered, the alarm module will automatically adjust parameter operations, such as reducing the intake volume, increasing the adsorbent regeneration frequency, etc., to slow down the rising trend of carbon dioxide concentration and try to keep the system operating within a safe range.

[0053] When a high-level warning is triggered, the alarm module immediately switches to backup equipment or performs an emergency shutdown to prevent system failure or damage due to excessive carbon dioxide concentrations. This step is the last line of defense to ensure safe system operation.

[0054] Preferably, the pretreatment process of the pretreatment unit effectively removes impurities and moisture from the flue gas, avoiding their interference with the adsorbent, which can significantly improve the adsorption efficiency of the subsequent adsorption unit for CO2, extend the service life of the adsorbent, and reduce operating costs. The control model set in the control unit can dynamically adjust the control rate, optimal adsorption parameters, optimal analysis parameters and pressure equalization cycle parameters according to real-time data, realizing the intelligence and automation of the capture process, improving the capture efficiency, ensuring the stability and reliability of the capture process, and reducing the risk of manual intervention and misoperation. The adsorption unit uses a high-efficiency adsorbent to selectively adsorb CO2 in the flue gas, realizing efficient and environmentally friendly CO2 capture. The desorption operation can release the adsorbed CO2 and store it in the storage unit, which provides convenience for subsequent processing and utilization. The capture device has the advantages of high efficiency, stability, and environmental protection. It can significantly reduce the emission of CO2 in flue gas and improve the utilization of CO2. It is of great significance to promote energy conservation, emission reduction and sustainable development.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A modular vacuum pressure swing adsorption FPSO carbon dioxide capture method, characterized in that: The steps include: Providing a capture device, the capture device comprising a pretreatment unit, an adsorption unit, a storage unit and a control unit; A control model is set in the control unit, and a control rate, an optimal adsorption parameter, an optimal analytical parameter, and a pressure equalization cycle parameter are outputted by the control model and fed back to an actuator of the control unit, so that the actuator controls the operation of the pretreatment unit, the adsorption unit, and the reservoir unit; The flue gas is cooled, compressed and dried by the pretreatment unit, and CO2 in the flue gas is adsorbed and desorbed by the adsorption unit, and the CO2 desorbed by the adsorption unit is stored in the storage unit; The control model adopts a model predictive control framework, and the control rate in the model predictive control framework is: in, For The system state vector at time t, For The system output vector at time t, For The control input of the time system, exist The external disturbance of the system at the moment, is the state transition parameter, To control the input parameters, is the disturbance input parameter, is an output parameter, Is to pass parameters directly; according to and setting goals , obtain the optimal control input sequence by minimizing the objective function and constraint function; Minimum objective function: Constraint function: in, is the time variation amplitude, is the number of time steps for prediction, is the output error weight parameter, To control the input variation parameters, To control the minimum constraint of the sequence, is the maximum constraint of the control sequence, is the minimum constraint of the system state vector, is the maximum constraint of the system state vector; The minimum objective function and constraint function will be satisfied It is sent to the actuator as the optimal control input sequence.

2. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 1, characterized in that: The pretreatment unit includes a raw gas precooler, a flue gas gas-liquid separator, a raw gas compressor, a raw gas cold dryer and a cold dryer gas-liquid separator, and the raw gas compressor is provided with a cooler; When the flue gas is cooled, compressed and dried by the pretreatment unit, the following steps are included: The flue gas first enters the raw gas precooler, which reduces the temperature of the flue gas from 200~250℃ to 60~100℃. The cooled flue gas flows into the flue gas-liquid separator to separate the first batch of condensate. Then the flue gas passes through the raw gas compressor to increase the pressure of the flue gas and cools it down through the cooler. The flue gas then enters the raw gas dryer for drying. The dried flue gas passes through the dryer gas-liquid separator to separate the second batch of condensate. Then the flue gas enters the adsorption unit.

3. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 2, characterized in that: The flue gas pressure is increased to greater than or equal to 0.4 MPa through the raw gas compressor.

4. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 2, characterized in that: The temperature of the flue gas is reduced to below 50° C. by the cooler.

5. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 1, characterized in that: The adsorption unit includes a plurality of adsorption towers, a vacuum pump and a clean gas buffer tank; When the adsorption unit is used to adsorb and desorb CO2 in the flue gas, the following steps are included: The flue gas pretreated by the pretreatment unit enters the adsorption tower, and the adsorbent in the adsorption tower adsorbs CO2 to separate CO2 from the flue gas. When the adsorbent reaches saturation, the adsorption tower is desorbed by a vacuum pump to allow the adsorbent in the adsorption tower to desorb CO2. The clean gas in the clean gas buffer tank is filled into the adsorption tower through the vacuum pump, so that the adsorption tower is re-pressurized and recycled.

6. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 5, characterized in that: The storage unit includes a CO2 compressor, a condenser, and a liquefied storage tank; The CO2 desorbed from the adsorption tower is compressed by a CO2 compressor, and the compressed gaseous CO2 is converted into liquid CO2. The liquid CO2 enters the condenser for cooling and then enters the liquefied storage tank for storage.

7. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 6, characterized in that: The control model also constructs a dual-objective optimization model : in, The capture device runs from the set time to the The accumulated energy consumption at the time, is the CO2 capture efficiency; The optimal adsorption parameters, optimal analytical parameters and pressure equalization cycle parameters are determined according to the dual-objective optimization model to achieve dynamic adjustment.

8. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 7, characterized in that: The capture device further includes a plurality of sensors for monitoring the pretreatment unit, the adsorption unit and the storage unit. The sensors collect data and transmit the data to the control unit in real time. The control unit is provided with an alarm module. The alarm calculation model in the alarm module is: in, For real-time measurement data, is the abnormal parameter of the capture system; when When the preset threshold is exceeded, the control center issues an early warning.

9. The modular vacuum pressure swing adsorption FPSO carbon dioxide capture method according to claim 8, characterized in that: The alarm module is equipped with a multi-level early warning mechanism. Multi-level early warning mechanism for: in, , is the first alarm threshold, is the second alarm threshold, is the third alarm threshold, First alarm level, Second alarm level, It is the third alarm level; The alarm module automatically triggers the corresponding alarm level according to the multi-level early warning mechanism and initiates emergency response operations, including adjusting operating parameters, switching to backup equipment, or performing emergency shutdowns to ensure stable operation of the system; When triggered When the alarm module is activated, it will automatically record the alarm log and back up the parameter data; When triggered When , the alarm module will perform the parameter adjustment operation; When triggered When the alarm is triggered, the alarm module will switch to the backup device or perform an emergency shutdown.

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