A modular vacuum pressure swing adsorption FPSO carbon dioxide capture method

Abstract

This invention relates to the field of carbon dioxide capture technology, and more particularly to a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method. The method provides a 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, which outputs control rate, optimal adsorption parameters, optimal desorption parameters, and equalization cycle parameters, and feeds them back to the actuators of the control unit. The actuators then control the operation of the pretreatment unit, the adsorption unit, and the storage unit. The pretreatment unit cools, compresses, and dries the flue gas. The adsorption unit adsorbs and desorbs CO2 from the flue gas. The desorbed CO2 is stored in the storage unit. This invention improves the efficiency and safety of carbon dioxide capture.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and more particularly to a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method. Background Technology

[0002] Floating Production Storage and Offloading (FPSO) units, with their unique integrated design and operating model, face 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 careful consideration of the complexity of the marine environment and operational safety during layout. Furthermore, FPSO power supply systems must meet more stringent requirements to ensure equipment safety and production efficiency while minimizing energy consumption. Therefore, the application of traditional CO2 capture technologies to FPSOs has certain limitations, necessitating the development of more adaptable technological solutions. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention provides a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method, which solves the technical problems of difficult and complex operation in FPSO carbon dioxide capture in the prior art, and improves the capture efficiency and safety of carbon dioxide.

[0004] This invention provides a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method, comprising the following steps:

[0005] A collection device is provided, which includes a pretreatment unit, an adsorption unit, a storage unit, and a control unit;

[0006] A control model is set in the control unit. The control model outputs the control rate, the optimal adsorption parameters, the optimal resolution parameters, and the equalization cycle parameters and feeds them back to the actuator of the control unit. The actuator then controls the operation of the pretreatment unit, the adsorption unit, and the storage unit.

[0007] The pretreatment unit cools, compresses, and dries the flue gas, while the adsorption unit adsorbs and desorbs CO2 from the flue gas. The CO2 desorbed by the adsorption unit is stored in the storage unit.

[0008] 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 feed gas precooler, a flue gas gas-liquid separator, a feed gas compressor, a feed gas refrigerated dryer, and a refrigerated dryer gas-liquid separator, wherein the feed gas compressor is equipped with a cooler.

[0009] When the flue gas is cooled, compressed, and dried by the pretreatment unit, the following steps are included:

[0010] 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 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 is cooled by the cooler. Then the flue gas enters the raw gas refrigerated dryer for drying. The dried flue gas passes through the refrigerated dryer gas-liquid separator to separate the second batch of condensate. After that, the flue gas enters the adsorption unit.

[0011] 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 using a feed gas compressor.

[0012] 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 means of the cooler.

[0013] 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 multiple adsorption towers, a vacuum pump, and a clean gas buffer tank.

[0014] When performing adsorption and desorption operations on CO2 in flue gas using the adsorption unit, the following steps are included:

[0015] The flue gas, after pretreatment by the pretreatment unit, enters the adsorption tower. The adsorbent in the adsorption tower adsorbs CO2 and separates CO2 from the flue gas. When the adsorbent reaches saturation, a vacuum pump is used to desorb CO2 from the adsorbent in the adsorption tower. Then, the clean gas in the clean gas buffer tank is pumped into the adsorption tower through the vacuum pump, so that the adsorption tower is repressurized and recycled.

[0016] 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.

[0017] The CO2 desorbed from the adsorption tower is compressed by a CO2 compressor. The compressed gaseous CO2 is converted into liquid CO2. The liquid CO2 enters the condenser for cooling and then enters the liquefaction storage tank for storage.

[0018] A further improvement of the modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method of the present invention lies in that the control model adopts a model predictive control framework, and the control rate in the model predictive control framework is:

[0019]

[0020]

[0021] in, For The system state vector at any given time. For The system output vector at time step For Control inputs of the timing system exist External disturbances to the system at all times. These are state transition parameters. To control the input parameters, These are disturbance input parameters. These are output parameters. It involves directly passing parameters;

[0022] according to and setting goals The optimal control input sequence is obtained by using the minimum objective function and the constraint function;

[0023] Minimum objective function:

[0024] Constraint functions:

[0025]

[0026] in, The amplitude of time variation, The number of time steps for prediction. It is the output error weight parameter. To control the input variation parameters, To control the minimum constraint of the sequence, To control the maximum constraint of the sequence, This is a constraint to minimize the system state vector. This is a constraint on maximizing the system state vector.

[0027] This will satisfy the minimum objective function and the constraint function. The optimal control input sequence is transmitted to the actuator.

[0028] A further improvement of the modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method of this invention lies in the fact that a dual-objective optimization model is also constructed for the control model. :

[0029]

[0030] in, The capture device operates from the set time to the [number]th [time]. Cumulative energy consumption over time For CO2 capture efficiency;

[0031] The optimal adsorption parameters, optimal analytical parameters, and equalization period parameters are determined based on a dual-objective optimization model to achieve dynamic adjustment.

[0032] A further improvement of the modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method of the present invention lies in that the capture device further includes several sensors. These sensors monitor the pretreatment unit, adsorption unit, and storage unit. The sensors collect data and transmit it to the control unit in real time. The control unit is equipped with an alarm module, and the alarm calculation model in the alarm module is as follows:

[0033]

[0034] in, For real-time collected measurement data, For capturing abnormal parameters of the system;

[0035] when When the preset threshold is exceeded, the control center issues an early warning.

[0036] 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 equipped with a multi-level early warning mechanism.

[0037] Multi-level early warning mechanism for:

[0038]

[0039] in, , The first alarm threshold is... This is the second alarm threshold. The third alarm threshold, First alarm level, Second alarm level, It is the third alarm level;

[0040] The alarm module automatically triggers the corresponding alarm level according to the multi-level early warning mechanism and initiates emergency handling operations. Emergency handling operations include adjusting operating parameters, switching to backup equipment, or performing an emergency shutdown to ensure the stable operation of the system.

[0041] When triggered When this happens, the alarm module will automatically record the alarm log and back up the parameter data;

[0042] When triggered When this happens, the alarm module will perform parameter adjustment operations;

[0043] When triggered In such cases, the alarm module will either switch to a backup device or perform an emergency shutdown.

[0044] This invention effectively removes impurities and moisture from flue gas through a pretreatment process in the pretreatment unit, avoiding their interference with the adsorbent. This significantly improves the CO2 adsorption efficiency of subsequent adsorption units, extends the adsorbent's lifespan, and reduces operating costs. The control model in the control unit dynamically adjusts the control rate, optimal adsorption parameters, optimal resolution parameters, and equalization cycle parameters based on real-time data, achieving intelligent and automated capture processes. This improves capture efficiency, ensures the stability and reliability of the capture process, and reduces the risk of human intervention and misoperation. The adsorption unit uses a highly efficient adsorbent to selectively adsorb CO2 from the flue gas, achieving efficient and environmentally friendly CO2 capture. The desorption operation releases the adsorbed CO2 and stores it in the storage unit, facilitating subsequent treatment and utilization. This capture device has advantages such as high efficiency, stability, and environmental friendliness, significantly reducing CO2 emissions from flue gas and improving CO2 utilization. It is of great significance for promoting energy conservation, emission reduction, and sustainable development.

[0045] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method provided by the present invention.

[0048] Figure 2 This is a schematic diagram of a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture device provided by the present invention.

[0049] Figure label:

[0050] 1. Primary vacuum pump; 2. Raw material gas compressor; 3. CO2 compressor; 4. Secondary vacuum pump; 5. Raw material gas refrigerated dryer; 6. Primary desorption gas buffer tank; 7. Primary backflow gas buffer tank; 8. Refrigerated dryer gas-liquid separator; 9. Raw material gas precooler; 10. Flue gas gas-liquid separator; 11. Primary adsorption tower; 12. Secondary adsorption tower; 13. Secondary inlet tower; 14. Secondary backflow gas buffer tank; 15. Secondary clean gas buffer tank; 16. Secondary desorption gas buffer tank. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but should not be used to limit the scope of this invention.

[0052] The following is combined with Figure 1 and Figure 2 The present invention describes a modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method, comprising the following steps:

[0053] A collection device is provided, which includes a pretreatment unit, an adsorption unit, a storage unit, and a control unit;

[0054] A control model is set in the control unit. The control model outputs the control rate, optimal adsorption parameters, optimal resolution parameters, and equalization cycle parameters and feeds them back to the actuator of the control unit. The actuator then controls the operation of the pretreatment unit, adsorption unit, and storage unit.

[0055] 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.

[0056] In a preferred embodiment of the modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method of the present invention, the pretreatment unit includes a feed gas precooler 9, a flue gas gas-liquid separator 10, a feed gas compressor 2, a feed gas refrigerated dryer 5, and a refrigerated dryer gas-liquid separator 8. The feed gas compressor 2 is equipped with a cooler. The flue gas first enters the feed gas precooler 9, where 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 pressure is increased to greater than or equal to 0.4MPa by the feed gas compressor 2, and the temperature is reduced to below 50℃ by the cooler. The flue gas then enters the feed gas refrigerated dryer 5 for drying. The dried flue gas passes through the refrigerated dryer gas-liquid separator 8 to separate the second batch of condensate, and then the flue gas enters the adsorption unit.

[0057] Ideally, the first and second batches of condensate can be discharged into the ocean after undergoing wastewater treatment procedures.

[0058] The raw gas precooler employs efficient heat exchange technology to rapidly and uniformly reduce the temperature of the flue gas, ensuring it reaches a suitable temperature range before entering subsequent processing steps. The flue gas-liquid separator 10 effectively separates liquid components from the flue gas, preventing adverse effects on downstream equipment. The raw gas compressor 2 is equipped with advanced compression technology and sealing devices, significantly increasing flue gas pressure while reducing energy loss and leakage risks. The cooler further reduces the temperature of the flue gas exiting the raw gas compressor, ensuring it operates within a safe and stable range. The raw gas refrigerated dryer 5 rapidly absorbs and removes moisture from the flue gas, ensuring the flue gas entering the adsorption unit is dry and pure. The refrigerated dryer gas-liquid separator 8 further separates the flue gas into gas and liquid components, ensuring the flue gas entering the adsorption unit is completely free of liquid components, thereby further improving adsorption efficiency and collection quality.

[0059] Furthermore, the adsorption unit includes multiple adsorption towers, a vacuum pump, and a clean gas buffer tank. The flue gas, after pretreatment by the pretreatment unit, enters the adsorption tower. The adsorbent in the adsorption tower adsorbs CO2 and separates CO2 from the flue gas. When the adsorbent reaches saturation, the adsorption tower is desorbed by the vacuum pump to desorb CO2. The clean gas in the clean gas buffer tank is then pumped into the adsorption tower by the vacuum pump to repressurize the adsorption tower for recycling.

[0060] Specifically, the adsorption unit includes a primary adsorption device and a secondary adsorption device; the primary adsorption device includes 10 primary adsorption towers 11, 2 primary vacuum pumps 1, 1 primary desorption gas buffer tank 6, and 1 primary reverse gas buffer tank 7; the secondary adsorption device includes 5 secondary adsorption towers 12, 1 secondary intake tower 13, 1 secondary vacuum pump 4, 1 secondary reverse gas buffer tank 14, 1 secondary clean gas buffer tank 15, and 1 secondary desorption gas buffer tank 16.

[0061] The pretreated flue gas enters the primary adsorption tower 11 from the bottom. 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 over 30%. When the adsorbent is close to saturation, the primary adsorption tower 11 undergoes two pressure equalization and depressurization processes and vacuum desorption under the action of the primary vacuum pump 1. The primary adsorption tower 11 performs a vacuum operation under the action of the primary vacuum pump 1 to desorb the CO2 on the adsorbent, which enters the primary desorption gas buffer tank 6. The primary adsorption tower 11 then undergoes pressure equalization and pressure increase through the pretreated flue gas to gradually restore the working pressure.

[0062] The gas in the primary desorption buffer tank 6 enters the secondary intake tower 13 through the primary reverse release buffer tank 7, and then enters the secondary adsorption tower 12. The secondary adsorption tower 12 operates at a pressure of 0.4 MPa. The adsorbent adsorbs CO2, increasing the CO2 concentration from about 5% to over 30%. When the adsorbent is close to saturation, the secondary adsorption tower 12 undergoes two pressure equalization and depressurization processes and vacuum desorption through the secondary vacuum pump 4. Under the action of the secondary vacuum pump 4, the secondary adsorption tower 12 performs a vacuum operation to desorb the CO2 from the adsorbent and enter the secondary desorption buffer tank 16. Clean gas from the secondary clean gas buffer tank 15 enters the secondary adsorption tower 12 to perform two pressure equalization and pressurization processes, gradually restoring the working pressure. The CO2 in the secondary desorption buffer tank 16 enters the storage unit for storage through the secondary reverse release buffer tank 14.

[0063] The control unit automatically adjusts the adsorption and desorption cycles based on the adsorbent's saturation state and the overall requirements of the collection device to achieve efficient CO2 capture. The vacuum pump creates a sufficient negative pressure environment during desorption, allowing CO2 in the adsorbent to be effectively released while avoiding potential secondary pollution. The clean gas buffer tank stores deeply purified gas, which is introduced after desorption in the adsorption tower. This not only aids in adsorbent regeneration but also ensures the continuous and stable operation of the entire collection device.

[0064] Furthermore, the storage unit includes a CO2 compressor 3, a condenser, and a liquefaction 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 liquefaction storage tank for storage.

[0065] The liquefied gas storage tank has excellent thermal insulation properties, effectively maintaining the low temperature of liquid CO2 and preventing it from re-vaporizing 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 tank, ensuring stable storage and efficient management of liquid CO2. The entire storage unit is designed with safety and reliability in mind, ensuring the efficiency and continuity of the CO2 capture process.

[0066] Furthermore, the control model adopts a model predictive control framework, and the control law in the model predictive control framework is:

[0067]

[0068]

[0069] in, For The system state vector at any given time. For The system output vector at time step For Control inputs of the timing system exist External disturbances to the system at all times. These are state transition parameters. To control the input parameters, These are disturbance input parameters. These are output parameters. It involves directly passing parameters;

[0070] according to and setting goals The optimal control input sequence is obtained by using the minimum objective function and the constraint function;

[0071] Minimum objective function:

[0072] Constraint functions:

[0073]

[0074] in, The amplitude of time variation, The number of time steps for prediction. It is the output error weight parameter. To control the input variation parameters, To control the minimum constraint of the sequence, To control the maximum constraint of the sequence, This is a constraint to minimize the system state vector. This is a constraint on maximizing the system state vector.

[0075] This will satisfy both the minimum objective function and the constraint function. The optimal control input sequence is transmitted to the actuator.

[0076] This control model predicts the future state of the capture unit in real time and adjusts the control input based on the prediction results to achieve optimal carbon dioxide capture performance. In practice, it first determines the system state vector, output vector, control input, and external disturbance parameters based on the actual conditions of the carbon dioxide capture unit on the FPSO. Then, it uses a model predictive control framework to calculate the optimal control input under given constraints. Through continuous iteration and optimization, this control model can adjust the operating pressure and temperature of the adsorption tower and the regeneration conditions of the adsorbent in real time, ensuring that the carbon dioxide capture unit always operates in an optimal state. Furthermore, this control model exhibits robustness, enabling it to cope with complex and variable marine environmental conditions and guaranteeing the stable operation of the carbon dioxide capture system on the FPSO.

[0077] After receiving the optimal control input sequence, the actuator will precisely regulate itself according to the instructions in the sequence. During the regulation process, the control unit will dynamically adjust the adsorption and desorption processes based on parameters such as current carbon dioxide concentration, pressure, and temperature to ensure that the carbon dioxide capture efficiency remains at a high level throughout the entire FPSO operation cycle.

[0078] The actuator precisely regulates each module in the vacuum pressure swing adsorption (VSA) system based on the received optimal control input sequence. This includes adjusting the operating pressure and temperature of the adsorption modules, as well as the regeneration conditions of the adsorbent, to ensure efficient carbon dioxide capture. Simultaneously, the system monitors the operating status of each module in real time via sensors, including key parameters such as pressure, temperature, and flow rate, and feeds this real-time data back to the control model. The control model then fine-tunes the optimal control input sequence based on the feedback data to adapt to various possible changes in 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 carbon dioxide capture.

[0079] Furthermore, the control model also constructed a dual-objective optimization model. :

[0080]

[0081] in, The capture device operates from the set time to the [number]th [time]. Cumulative energy consumption over time For CO2 capture efficiency;

[0082] The optimal adsorption parameters, optimal analytical parameters, and equalization period parameters are determined based on a dual-objective optimization model to achieve dynamic adjustment.

[0083] This dual-objective optimization model comprehensively considers the balance between energy consumption and capture efficiency, aiming to find the optimal combination of operating parameters so that the system can minimize energy consumption while ensuring efficient CO2 capture. Through precise mathematical models and algorithms, the control model can analyze and predict energy consumption and capture efficiency under different parameters in real time, thereby determining the optimal operating strategy.

[0084] Preferably, the state transition parameters, control input parameters, disturbance input parameters, output parameters, direct transfer parameters, output error weight parameters, and control input variation parameters are all fixed parameters in the control model, and their values ​​are as follows: State transition parameters Control input parameters Disturbance input parameters Output parameters Pass parameters directly Output error weight parameters Control input change parameters .

[0085] In one specific embodiment, the system state vector is used to describe the internal state of the system. ,in, This indicates the CO2 concentration inside the adsorption tower. Indicates the pressure of the adsorption tower. Indicates the temperature of the adsorbent;

[0086] The system output vector is used to describe the system's measurable output. ,in, Indicates CO2 capture efficiency. Indicates the net flue gas flow rate; the system's control inputs describe the adjustable control inputs. ,in, This indicates the set pressure of the adsorption tower. This indicates the set vacuum intensity of the vacuum pump; external disturbances are used to indicate the initial CO2 concentration in the flue gas entering the system.

[0087] The state transition parameters, control input parameters, disturbance input parameters, output parameters, and direct transfer parameters are respectively: ;

[0088] The prediction time step is 10, and the output error weighting parameter is... Control input change parameters Minimum constraint of control sequence Maximum constraint of control sequence ， System state vector minimum constraint Maximum constraint of system state vector ， Set goals Objective function

[0089] ,in, Indicates in The output error term at time 10:00 Indicates in Control variables at any given time;

[0090] ,in, Indicates the change value of the control input;

[0091] The specific steps are:

[0092] Set initial conditions ;

[0093] Predicting state evolution ;

[0094] Calculation example:

[0095]

[0096] ;

[0097] Calculate the objective function: ; Assumption ,

[0098] ,

[0099] Output error term

[0100] Control change items

[0101] Constraint handling: The condition 0.35 ≤ 5.38 ≥ 0.6 does not satisfy the constraint function.

[0102] Then continue the calculation. ,

[0103] 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.

[0104] Regarding the selection of optimal parameters, as mentioned earlier, 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.).

[0105] Constraint functions that satisfy the minimum objective function The optimal control input sequence is transmitted to the actuator.

[0106] Optimal control input sequence for:

[0107]

[0108] The parameter setting process is shown in Table 1:

[0109] Table 1

[0110]

[0111] Note: The weighting ratio is set as energy consumption:efficiency = 0.6:0.4.

[0112] The control model calculates the corresponding parameters for each group. ,choose The smallest set of parameters is taken as the optimal set; when the weights need to be adjusted to favor energy consumption or efficiency, the parameters are recalculated. The parameter range is dynamically adjusted through network search, and real-time adjustments are made to meet changes in operating conditions.

[0113] As shown in Table 1, the minimum value corresponding to group 1 (adsorption pressure of 0.40 MPa, desorption pressure of 0.05 MPa, and pressure equalization period of 10 min) is selected as the optimal adsorption parameter, optimal desorption parameter, and pressure equalization period parameter.

[0114] Since the initial state and disturbances are unknown, the control law depends on the specific scenario, and generally takes the form of: ,in The pressure was tracked by varying the pressure between 0.35 and 0.6 MPa. Adjust the vacuum level by varying the pressure between 20 and 100 kPa.

[0115] Under optimal parameters (adsorption pressure 0.40 MPa, desorption pressure 0.05 MPa), the control efficiency may be biased towards the adsorption stage. ≈0.40, ≈0, Analysis phase ≈0.05, ≈80, but optimization is needed to solve it.

[0116] The numerical examples above 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 for the optimal control input sequence.

[0117] Specifically, the collection device also includes several sensors. These sensors monitor the pretreatment unit, adsorption unit, and storage unit. The sensors collect data and transmit it to the control unit in real time. The control unit is equipped with an alarm module, and the alarm calculation model in the alarm module is as follows:

[0118]

[0119] in, For real-time collected measurement data, For capturing abnormal parameters of the system;

[0120] when When the preset threshold is exceeded, the control center issues an early warning.

[0121] These sensors cover critical operating parameters such as temperature, pressure, flow rate, and gas concentration, ensuring that every detail of the system's operation is precisely monitored. Once the sensors detect any abnormal data, such as an abnormally high inlet temperature in the pretreatment unit or an excessive CO2 concentration at the adsorption unit's outlet, this real-time collected measurement data is immediately transmitted to the control unit. The alarm calculation model within the control unit quickly analyzes this data, comparing it to preset abnormal parameter thresholds. If the measured data exceeds the preset safety range, the alarm module immediately triggers the early warning mechanism. The control center receives the alarm signal and immediately takes countermeasures, such as adjusting operating parameters, activating backup equipment, or performing an emergency shutdown, to prevent potential safety accidents and ensure the stable and safe operation of the capture system.

[0122] Specifically, the alarm module is equipped with a multi-level early warning mechanism.

[0123] Multi-level early warning mechanism for:

[0124]

[0125] in, , The first alarm threshold is... This is the second alarm threshold. The third alarm threshold, First alarm level, Second alarm level, It is the third alarm level;

[0126] The alarm module automatically triggers the corresponding alarm level according to the multi-level early warning mechanism and initiates emergency handling operations. Emergency handling operations include adjusting operating parameters, switching to backup equipment, or performing an emergency shutdown to ensure the stable operation of the system.

[0127] When triggered When this happens, the alarm module will automatically record the alarm log and back up the parameter data;

[0128] When triggered When this happens, the alarm module will perform parameter adjustment operations;

[0129] When triggered In such cases, the alarm module will either switch to a backup device or initiate an emergency shutdown.

[0130] Preferably, the first alarm threshold is set at 80% of the safe upper limit for carbon dioxide concentration, the second alarm threshold is set at 90% of the safe upper limit, and the third alarm threshold is set at exceeding the safe upper limit. The first alarm level is a basic warning, the second alarm level is a medium warning, and the third alarm level is a high warning.

[0131] When a primary warning is triggered, the alarm module will automatically record the alarm log and back up the current system's operating parameter data for subsequent analysis and troubleshooting. This step ensures data integrity and traceability, providing crucial information for fault diagnosis.

[0132] When a medium-level warning is triggered, the alarm module will automatically perform parameter adjustment operations, such as reducing the intake air volume and increasing the adsorbent regeneration frequency, in order to slow down the rising trend of carbon dioxide concentration and maintain the system operating within a safe range as much as possible.

[0133] When a high-level warning is triggered, the alarm module will immediately switch to backup equipment or perform an emergency shutdown to prevent system malfunction or damage due to excessive carbon dioxide concentration. This step is the last line of defense to ensure the safe operation of the system.

[0134] Preferably, the pretreatment process of the pretreatment unit effectively removes impurities and moisture from the flue gas, avoiding their interference with the adsorbent. This significantly improves the CO2 adsorption efficiency of subsequent adsorption units, extends the adsorbent's lifespan, and reduces operating costs. The control model set in the control unit can dynamically adjust the control rate, optimal adsorption parameters, optimal resolution parameters, and equalization cycle parameters based on real-time data, realizing intelligent and automated capture processes. This improves capture efficiency, ensures the stability and reliability of the capture process, and reduces the risk of manual intervention and misoperation. The adsorption unit uses a highly efficient adsorbent to selectively adsorb CO2 from the flue gas, achieving efficient and environmentally friendly CO2 capture. The desorption operation releases the adsorbed CO2 and stores it in the storage unit, facilitating subsequent treatment and utilization. This capture device has advantages such as high efficiency, stability, and environmental friendliness, significantly reducing CO2 emissions from flue gas and improving CO2 utilization. It is of great significance for promoting energy conservation, emission reduction, and sustainable development.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method, characterized in that, Includes the following steps: A collection device is provided, which includes a pretreatment unit, an adsorption unit, a storage unit, and a control unit; A control model is set in the control unit. The control model outputs the control rate, the optimal adsorption parameters, the optimal resolution parameters, and the equalization cycle parameters and feeds them back to the actuator of the control unit. The actuator then controls the operation of the pretreatment unit, the adsorption unit, and the storage unit. The pretreatment unit cools, compresses, and dries the flue gas, and the adsorption unit adsorbs and desorbs CO2 from the flue gas. 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 law in the model predictive control framework is: in, In order to be in The system state vector at any given time. In order to be in The system output vector at time step In order to be in Control inputs of the timing system exist External disturbances to the system at all times. These are state transition parameters. To control the input parameters, These are the disturbance input parameters. These are output parameters. It involves directly passing parameters; according to and setting goals The optimal control input sequence is obtained by using the minimum objective function and the constraint function; Minimum objective function: Constraint functions: in, The amplitude of time variation, The number of time steps for prediction. It is the output error weight parameter. To control the input variation parameters, To control the minimum constraint of the sequence, To control the maximum constraint of the sequence, This is a constraint to minimize the system state vector. This is a constraint on maximizing the system state vector. This will satisfy the minimum objective function and the constraint function. The optimal control input sequence is transmitted to the actuator. The adsorption unit includes multiple adsorption towers, a vacuum pump, and a clean gas buffer tank. When performing adsorption and desorption operations on CO2 in flue gas using the adsorption unit, the following steps are included: The flue gas, after pretreatment by the pretreatment unit, enters the adsorption tower. The adsorbent in the adsorption tower adsorbs CO2 and separates CO2 from the flue gas. When the adsorbent reaches saturation, the adsorption tower is desorbed by a vacuum pump so that the adsorbent in the adsorption tower desorbs CO2. The clean gas in the clean gas buffer tank is then pumped into the adsorption tower by a vacuum pump so that the adsorption tower is repressurized and recycled. 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. The compressed gaseous CO2 is converted into liquid CO2. The liquid CO2 enters the condenser for cooling and then enters the liquefaction storage tank for storage.

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 refrigerated dryer, and a refrigerated dryer gas-liquid separator. The raw gas compressor is equipped 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 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 is cooled by the cooler. Then the flue gas enters the raw gas refrigerated dryer for drying. The dried flue gas passes through the refrigerated dryer gas-liquid separator to separate the second batch of condensate. After that, 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 pressure of the flue gas is increased to greater than or equal to 0.4 MPa by a raw material gas compressor.

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

5. The modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method according to claim 1, characterized in that, The control model also constructed a dual-objective optimization model. : in, The capture device operates from the set time to the [number]th [time]. Cumulative energy consumption over time For CO2 capture efficiency; The optimal adsorption parameters, optimal analytical parameters, and equalization period parameters are determined based on a dual-objective optimization model to achieve dynamic adjustment.

6. The modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method according to claim 5, characterized in that, The collection device also includes several sensors for monitoring the pretreatment unit, adsorption unit, and storage unit. The sensors collect data and transmit it to the control unit in real time. The control unit is equipped with an alarm module, and the alarm calculation model in the alarm module is as follows: in, For real-time collected measurement data, For capturing abnormal parameters of the system; when When the preset threshold is exceeded, the control center issues an early warning.

7. The modular vacuum pressure swing adsorption (FPSO) carbon dioxide capture method according to claim 6, characterized in that, The alarm module is equipped with a multi-level early warning mechanism. Multi-level early warning mechanism for: in, , The first alarm threshold is... This is the second alarm threshold. 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 handling operations. Emergency handling operations include adjusting operating parameters, switching to backup equipment, or performing an emergency shutdown to ensure the stable operation of the system. When triggered When this happens, the alarm module will automatically record the alarm log and back up the parameter data; When triggered When this happens, the alarm module will perform parameter adjustment operations; When triggered In such cases, the alarm module will either switch to a backup device or perform an emergency shutdown.

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