Time series deep seabed leakage gas capture device and in-situ monitoring method

Abstract

The present invention relates to the technical field of marine observation equipment, specifically to a time-series deep-sea seabed leakage gas capture device and an in-situ monitoring method, comprising a bracket, the bracket being connected to a floating block by wrapping the outside to form an inner cavity therein, the floating block at the top of the inner cavity being sealedly connected to a fixed platform between the bracket, a rotating platform being rotatably mounted on the fixed platform, the rotating platform being provided with a plurality of mounting ports penetrating the rotating platform, and an inverted sampling bottle being detachably mounted at the mounting port, the sampling bottle being provided with an electromagnetic valve at the opening, a sampling port penetrating the fixed platform being provided directly below the circular trajectory of the mounting port, the bottom surface of the fixed platform being connected to a gas capturer at the sampling port; a counterweight seat being connected between the bottom of the inner cavity and the bracket, which can be separated from the bracket by an acoustic releaser, and a through port being provided on the counterweight seat for seabed gas to enter the inner cavity. The present invention has low deployment and recovery requirements, causes little disturbance to the seabed, can be deployed and recovered quickly and repeatedly, and meets the needs of long-term in-situ multiple sampling.

Description

Technical Field

[0001] The present invention relates to the technical field of ocean observation equipment, and in particular to a time-series deep-sea seabed leakage gas capture device and an in-situ monitoring method. Background Art

[0002] Submarine gas seepage refers to the process by which gases from within the seabed are transferred upward from various sources into the seawater through various forcing mechanisms, including sediment compaction, seabed overpressure caused by the dissociation of natural gas hydrates into methane, biogeochemical reactions, biological activity, and phase transformations. Analysis of the composition and concentration of submarine gas seepage can indicate the source of the seeping gas, thereby reflecting changes in the marine geochemistry and tectonic geology within the seabed. However, in situ analysis of seepage gas at deep seabed depths is difficult to achieve. Therefore, submarine gas seepage is typically captured in situ to obtain samples for laboratory analysis.

[0003] Subsea gas seepage is a phenomenon driven by a variety of geological and biochemical processes, and its long-term evolution is of great significance for studying seafloor tectonic structures and the carbon cycle. Existing gas sampling devices commonly suffer from the following issues: Sample contamination: Traditional permeable stone filters are easily clogged by suspended matter, resulting in reduced sample quality. Inadequate gas separation: The gas-liquid mixture remains untreated during sampling, making it difficult to obtain high-purity gas samples. Lack of seepage velocity measurement: Existing devices are unable to accurately calculate gas seepage velocity.

[0004] Currently, there are two main types of disclosed seabed gas collection devices: active gas collection devices that penetrate the seabed (Chinese invention patent applications CN115493897A and CN107269251B), and passive gas collection devices placed on the seabed surface (Chinese invention patent application CN111735671A). The former is typically used for shallow-water seabed gas collection. Directly transplanting this technology to the deep sea requires a complex, large-scale seabed penetration mechanism, which significantly disturbs the seabed. Furthermore, active penetration-type gas collection destroys the pore structure of in-situ sediments, potentially contaminating the collected samples and leading to significant measurement errors. Passive gas collection devices typically utilize large in-situ collection devices, using sealable sample collection bottles. This method causes minimal disturbance to the seabed sediments and enables non-destructive collection. However, the disclosed technology (Chinese invention patent application CN111735671A) requires the deployment and retrieval of the device using a large underwater vehicle (ROV), which is not feasible with ordinary marine research vessels and is costly. In addition, there is currently no technical means to achieve in-situ time series sampling of seabed gas leakage, resulting in the inability to understand the long-term changes in seabed gas leakage.

[0005] Obviously, for the complex and changeable marine environment, the above-mentioned technical methods that have been applied for disclosure still have defects and cannot meet the existing practical application needs. This is a problem that needs to be solved urgently. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a time-series deep-sea seabed leakage gas capture device and in-situ monitoring method, which can realize continuous, low-disturbance, and automated gas leakage sampling in a deep-sea environment. It has low deployment and recovery requirements, causes little disturbance to the seabed, can be deployed and recovered quickly and repeatedly, and meets the needs of long-term in-situ multiple sampling. It aims to improve sampling accuracy and sample purity and realize real-time calculation of leakage rate.

[0007] The present invention is achieved through the following technical solutions:

[0008] A time-series deep-sea seabed leakage gas capture device is provided, comprising a bracket, wherein the bracket is connected to a floating block by external wrapping, and an inner cavity for accommodating leakage gas is formed in the bracket, the top of the inner cavity is sealed with a fixed platform between the floating block and the bracket, a rotating platform driven by a deep-water motor is rotatably installed on the fixed platform, a plurality of mounting ports located on the same circular trajectory and passing through the rotating platform are provided on the rotating platform, and an inverted sampling bottle is detachably installed at the mounting port, an electromagnetic valve is installed at the opening of the sampling bottle, and a pressure and temperature sensor is built into the sampling bottle, a sampling port passing through the fixed platform is provided on the fixed platform directly below the circular trajectory of the mounting port, a gas capturer is connected to the bottom surface of the fixed platform at the sampling port, and an electric control valve is also installed in the sampling port at the connection with the gas capturer; the bracket is connected to a counterweight seat at the bottom of the inner cavity, which can be separated from the bracket by an acoustic releaser, and a through hole for seabed gas to enter the inner cavity is provided on the counterweight seat.

[0009] In this scheme, the main function of the buoyancy block is to provide buoyancy for the device, ensuring its stability in seawater. A cavity is formed between the support and the buoyancy block to contain leaking gas. This cavity is used to capture gas leaking from the seabed. The top of the cavity is sealed to the fixed platform, ensuring that the gas inside the cavity cannot leak, thereby effectively collecting the leaked gas. A sampling port is located below the fixed platform, running through the entire platform and connected to a gas capture device. The gas capture device extracts the collected leaked gas sample from the sampling bottle, ensuring sample integrity and preventing any gas loss during the collection process. The connection between the sampling port and the gas capture device is precisely positioned to ensure that the capture device can quickly and accurately capture the leaked gas after the sampling bottle is replaced. The main function of the counterweight base is to increase the stability of the device, preventing it from shifting or tilting during long-term operation on the seabed. The counterweight base is designed with a dedicated opening to allow gas leaking from the seabed to enter the cavity, ensuring that the gas is effectively channeled into the sampling bottle during the collection process. To enable remote control and automated operation, a hydroacoustic transducer is mounted at the center of the rotating platform. Its primary function is to facilitate communication between the device and surface vessels, ensuring the device can receive commands from them. A control cabin, located on the underside of the fixed platform, houses a controller and a lithium battery pack for power. The controller is electrically connected to the deepwater motor, solenoid valve, and acoustic release, providing precise control commands to keep these components operating according to pre-set procedures. Furthermore, the controller's input is electrically connected to the hydroacoustic transducer, ensuring the device can receive control commands from surface vessels and wirelessly communicate with the vessel's control system.

[0010] Furthermore, a hydroacoustic transducer is installed at the center of the circular track of the installation port on the rotating platform, and a control cabin is installed on the bottom of the fixed platform. A controller and a lithium battery pack for power supply are provided in the control cabin. The output end of the controller is electrically connected to the deep-water motor, solenoid valve and acoustic releaser respectively, and the input end of the controller is electrically connected to the hydroacoustic transducer. The hydroacoustic transducer can communicate wirelessly with the control system of the surface vessel.

[0011] Furthermore, a groove with a radius smaller than the circular trajectory radius of the mounting port is formed in the center of the surface of the fixed platform. The rotating shaft is vertically fixed in the center of the groove. The upper end of the rotating shaft is rotatably connected to the rotating platform through a bearing. A fixed gear with the center penetrated by the rotating shaft is also fixed on the rotating shaft. A driving gear meshing with the fixed gear is provided in the groove. The deep-water motor is fixed to the bottom surface of the rotating platform and its driving shaft is connected to the center of the driving gear.

[0012] A rotating platform is mounted on a fixed platform, driven by a deepwater motor. Several removable mounting ports are located on a circular trajectory that extends through the platform. Each port accommodates a removable inverted sampling bottle. A solenoid valve is installed at the bottle opening to precisely control the entry of the gas sample during sampling. The solenoid valve automatically opens and closes at set intervals, ensuring that each bottle collects the sample within the appropriate timeframe.

[0013] Furthermore, the gas capturer includes an outer shell and a gas separation module arranged in the outer shell. The lower part of the outer shell of the gas capturer is provided with an air inlet, and the upper part is provided with an air outlet. The air inlet, the gas separation module and the air outlet together form a gas flow channel for the entry of the water-gas mixture; the gas separation module includes a separation section composed of a polymer multi-layer separation membrane structure and a centrifugal impeller. The polymer multi-layer separation membrane structure is arranged near the air outlet, and a multi-layer membrane structure formed by polymer separation membranes with different pore sizes is arranged therein. The outer layer of the multi-layer membrane structure is a large-pore membrane, and the inner layer is a small-pore membrane, and the pore size of the membrane decreases successively from the outer layer to the inner layer; the centrifugal impeller is arranged near the air inlet, and is a rotating blade driven by an electromagnetic drive device, which is used to drive the water-gas mixture into the separation section, and the separation section is used for step-by-step separation of water and gas.

[0014] The centrifugal impeller is a key mechanical component in a gas separation module. It is typically used to generate centrifugal force through rotation, helping to separate the different components in a gas mixture. The main functions of the centrifugal impeller include: Airflow acceleration and diversion: The centrifugal force generated by the high-speed rotation of the centrifugal impeller causes the gas flow direction to change, typically from axial to radial, thereby accelerating the gas flow. Under the action of the centrifugal impeller, the gas is rapidly accelerated and dispersed, thereby improving the contact efficiency between the gas and the separation medium (such as a membrane or adsorbent). Particle separation: The rotation of the centrifugal impeller generates strong centrifugal force, which propels heavier particles (such as dust and liquid droplets) toward the outer wall, thereby separating the particles from the gas. Especially in gas mixtures containing droplets or particles, the centrifugal impeller can effectively help the particles settle or aggregate, facilitating further gas purification. Enhanced gas flow uniformity: Before the gas mixture enters the separation module, the centrifugal impeller accelerates the airflow, promoting uniform gas flow within the module, thereby improving overall separation efficiency.

[0015] The rotation of the centrifugal impeller is typically powered by an electromagnetic drive. The advantages of electromagnetic drive are its fast response speed and high control precision. By adjusting the current, the impeller's speed can be precisely controlled, thereby adjusting the airflow speed and centrifugal force.

[0016] The electromagnetic drive device includes the following main parts:

[0017] Electromagnetic coil: The electromagnetic coil is the core of the drive unit. When energized, it generates electromagnetic force to drive the centrifugal impeller. The magnitude and frequency of the current can control the impeller's speed, thereby regulating the gas separation process.

[0018] Rotor and impeller connection: The centrifugal impeller is connected to an electromagnetic drive via a rotating shaft (rotor). The electromagnetic force generated by the electromagnetic coil acts on the rotor, causing it to rotate and drive the centrifugal impeller. The rotor typically has good magnetic conductivity to facilitate the transmission of the electromagnetic force.

[0019] Regulation system: The electromagnetic drive is equipped with a regulation system that adjusts the current in real time according to different operating conditions, thereby controlling the impeller speed and separation efficiency. The regulation system is usually linked to a controller and sensors to achieve automated control.

[0020] The connection between the centrifugal impeller and the electromagnetic drive device is primarily achieved through the rotor shaft. Specifically, the rotor shaft serves as the force transmission medium between the centrifugal impeller and the electromagnetic drive device and is typically located between the electromagnetic coil and the impeller. When the electromagnetic drive device generates a rotational torque through the electromagnetic coil, the rotor shaft transmits this torque to the centrifugal impeller, causing it to rotate. The electromagnetic coil within the electromagnetic drive device is connected to the rotor shaft via fixed bearings and a support structure. The other end of the rotor shaft is fixed to the centrifugal impeller to ensure that the impeller does not fall off during rotation. The bearing system provides smooth rotation, reduces wear, and improves system stability. The working principle of the electromagnetic drive device: The rotating magnetic field generated by the electromagnetic coil acts on the rotor shaft, driving it to rotate. The centrifugal impeller on the rotor shaft rotates at high speed as the shaft rotates, generating centrifugal force that diverts and accelerates the gas.

[0021] The electromagnetic drive is typically located at the bottom or side of the gas separation module, near the axis of the centrifugal impeller. The electromagnetic drive shown in the figure directly drives the connected rotor shaft through electromagnetic force, thereby driving the rotation of the centrifugal impeller. Connection between the electromagnetic drive and the centrifugal impeller: The electromagnetic coil in the electromagnetic drive is magnetically connected to the rotor shaft, which is directly connected to the centrifugal impeller. The rotation of the rotor shaft generates a rotational force that rotates the centrifugal impeller and initiates the generation of centrifugal force, aiding gas separation.

[0022] Furthermore, a plurality of handles extending out of the floating block are connected to the circumferential side of the bracket, and a gas release port is provided at each handle, and the position of the gas release port is higher than the gas collection inlet.

[0023] Each handle features two gas release ports for releasing gas that accumulates at the top. These ports provide internal and external connectivity, ensuring proper fluid exchange and preventing excessive gas accumulation from distorting internal sampling. The gas release ports are positioned above the gas collection inlet to prevent excessive gas from entering the time-series gas collection port, thereby preventing contamination of the collected gas sample. This design effectively reduces contamination of the gas sample and ensures accurate and reliable sampling.

[0024] Furthermore, the sealed inner cavity formed by the floating block and the bracket is in a prism shape.

[0025] The pyramid-shaped inner cavity can facilitate gas accumulation for easy collection and capture.

[0026] Furthermore, the collecting bottle is detachably connected to the rotating platform via a spring locking buckle.

[0027] The sampling bottle is detachably connected to the rotating platform through a spring locking buckle, which is convenient for taking, placing and replacing.

[0028] Furthermore, the upper end of the bracket passes through the fixed platform to form a guardrail surrounding the rotating platform.

[0029] The bracket forms a guardrail above the fixed platform, which can protect the sampling bottles on the rotating platform and prevent collisions with the sampling bottles during diving or collection to ensure the stability of sampling.

[0030] An in-situ monitoring method using a time series deep seabed gas leakage capture device comprises the following steps:

[0031] S1. Deployment:

[0032] S11. Preparation before deployment: After confirming that all components in the device are working normally, the manipulator of the underwater robot (ROV) grasps the guardrail on the top of the device and brings the entire device to a stable deployment depth.

[0033] S12. Positioning and deployment: The ROV uses an underwater camera to determine the exact location of the seabed gas leak, ensuring that the device is directly above the leak point. The manipulator slowly releases the device to the seabed so that the device covers the gas leak point.

[0034] S2. Collection:

[0035] S21. Activation device: After the device is deployed, it receives activation commands from surface vessels through the underwater acoustic transducer. The underwater acoustic transducer is connected to the vessel's communication system in real time to ensure accurate transmission of commands.

[0036] S22. Timed sampling: The device automatically opens the solenoid valve at a preset time interval to start the sampling process. The automatic control of the solenoid valve ensures that the leakage gas mixed with seawater samples are accurately collected within the set time, and the collection bottle is filled with a certain amount of sample each time.

[0037] S23. Sample replacement: After completing a sample collection, the solenoid valve automatically closes to prevent more seawater from entering the sampling bottle. The deep-water motor drives the rotating platform to rotate the preset angle so that the second sampling bottle is aligned with the sampling port and docked with the gas capturer. Each sampling bottle completes the sample exchange at the set angle.

[0038] S24. Repeated sampling: Complete the collection of all sample bottles in sequence, after completing the task of each sampling bottle.

[0039] S25. High-precision time control: Accurately control the time of each sampling task, keep the time interval between each sampling point consistent, and obtain accurate time series data.

[0040] S3. Recycling:

[0041] S31. Triggering the recovery command: When the sampling task is completed, the surface vessel sends a release command through the underwater acoustic transducer to trigger the recovery of the device. After receiving the release command, the controller controls the acoustic releaser to activate the fuse function.

[0042] S32. Counterweight release and ascent: After receiving the command, the acoustic releaser is powered on and the fuse is quickly blown. The device separates from the counterweight seat and begins to ascent. The controller tracks the ascent process of the device in real time and transmits the real-time depth and ascent progress to the surface ship through underwater acoustic communication.

[0043] S33, Floating and Recovery: The device rises at a floating speed of 1 meter per second and surfaces;

[0044] S34. Post-recovery operation: After recovery to the water surface, the staff can check the device, quickly replace the sampling bottle and the bottom weight, and be ready to deploy again after debugging and inspection to achieve cyclic deployment and recovery.

[0045] Furthermore, after completing each sampling task of a collection bottle, the device enters a silent state until the next sampling time point ends the silent state.

[0046] The silent mode helps save power, extend the device's operating time, and avoid unnecessary energy consumption. By setting the silent mode, you can save power between sampling bottles, which helps improve the device's battery life.

[0047] Furthermore, in step S2, the gas leakage rate Q can be calculated in real time during sampling by the sampling bottle to achieve long-term series observation. The formula is as follows:

[0048]

[0049] Where: ΔP is the change in gas pressure, V is the effective volume of the sampling bottle, T is the ambient temperature, R is the ideal gas constant, Δt is the sampling time interval, k filter is the multi-stage filtration membrane pass rate coefficient, k centrifge is the centrifugal separation efficiency coefficient, Q in is the gas flow rate at the centrifugal impeller inlet, Q out is the gas flow rate at the centrifugal impeller outlet, T i is the transmittance of the ith filter membrane, and n is the number of filter membrane stages.

[0050] Beneficial effects of the present invention:

[0051] 1. For the first time, the system has realized the automatic in-situ time series sampling of deep-sea seabed gas leakage, which has the function of long-term continuous capture of seabed gas leakage and improved the ability to observe the long-term changes of leakage gas in detail.

[0052] Second, the system uses a submarine acoustic release device to control the device for jettisoning and recovery, which increases the speed of the device's submarine recovery, reduces application costs, and facilitates rapid redeployment. To capture multiple submarine gas leaks, multiple collection devices can be deployed sequentially using an ROV. This device relies solely on the ROV for precise deployment and does not rely on the ROV for recovery. Compared to similar devices currently available, this significantly reduces observation costs.

[0053] 3. The device is wrapped with floating material on the outside, with a small load and a small contact area with the seabed, which reduces the disturbance to the seabed gas leakage channel, avoids the potential contamination of samples by local subsidence of the seabed caused by large-load heavy sampling devices, and improves the quality of observation data of leaking gas.

[0054] Fourth, the device can be quickly redeployed by replacing modular gas capture sample bottles and bottom weights, improving the high-time-resolution capture and analysis capabilities and utilization efficiency of seabed leakage gas.

[0055] 5. The overall modular structure design of the device has fewer mechanical moving parts, high overall system stability, and high gas capture reliability. It can take into account the reliability of the overall structure of the device and the efficiency of intermittent debugging for rapid and repeated use.

[0056] The device's modular design allows for easy replacement and adjustment of components, such as the sampling bottle, counterweight, and battery, based on actual needs. This design not only enhances the device's flexibility but also significantly simplifies its operation, enabling rapid deployment, sampling, and recovery in complex marine environments. This modular design ensures the device's high efficiency and reusability, significantly reducing maintenance costs during long-term seabed monitoring.

[0057] This device is not only suitable for sampling a single gas leak, but can also be deployed sequentially via ROV to capture multiple subsea gas leaks. Because it does not rely on ROV recovery, the recovery effort and costs are reduced, making it suitable for large-scale, multi-point gas leak capture missions.

[0058] This invention improves traditional gas sampling equipment by introducing a gas separation module, a high-fidelity sampling module, and an intelligent filter. Combined with a gas leakage rate calculation algorithm, it significantly improves the sampling accuracy and data analysis capabilities of the equipment, providing technical support for long-term monitoring and precise research of deep-sea gas leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0060] Figure 2 for Figure 1 Top view of .

[0061] Figure 3 for Figure 1 Front view of .

[0062] Figure 4 It is a cross-sectional view of the present invention.

[0063] Figure 5 It is a schematic diagram of the bracket installation structure of the present invention.

[0064] Figure 6 for Figure 5 Top view of .

[0065] Figure 7 It is a schematic diagram of the installation structure of the rotating platform and the fixed platform in the present invention.

[0066] Figure 8 It is a cross-sectional schematic diagram of the present invention.

[0067] As shown in the figure:

[0068] 1. Counterweight seat, 2. Float, 3. Handle, 4. Sampling bottle, 5. Sonar transducer, 6. Guardrail, 7. Rotating platform, 8. Control cabin, 9. Gas capture device, 10. Fixed platform, 11. Bracket, 12. Mounting port, 13. Inner cavity, 14. ROV manipulator, 15. Deepwater motor, 16. Groove, 17. Rotating shaft, 18. Fixed gear, 19. Driving gear, 20. Sampling port, 21. Air inlet, 22. Air outlet, 23. Centrifugal impeller, 24. Polymer multilayer separation membrane structure, 25. Electromagnetic drive device. DETAILED DESCRIPTION

[0069] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0070] A time-series deep-sea bottom gas leakage capture device includes a bracket 11, which is connected to a buoy 2 by wrapping around it. The bracket 11 has an internal cavity 13 formed therein to accommodate the leaked gas. The cavity 13 formed by the buoy 2 and bracket 11 is prism-shaped. Multiple handles are attached to the bracket's circumferential sides, extending from the buoy. Each handle has a gas release port positioned above the gas collection inlet, allowing for deployment in conjunction with an ROV manipulator 14. A fixed platform 10 is sealedly connected to the top of the cavity 13 between the buoy 2 and bracket 11. The upper end of bracket 11 extends through the fixed platform 10 to form a guardrail 6 circumferentially surrounding a rotating platform 7. The guardrail 6 provides protection for the sample collection bottle 4 and the hydroacoustic transducer 5 and can also be used to lift the equipment. The hydroacoustic transducer 5 is used for long-distance communication with surface vessels from the seabed, transmitting information such as device status and battery level, while also receiving control commands from the surface vessel.

[0071] A rotating platform 7 driven by a deep-water motor 15 is rotatably installed on the fixed platform 10. Specifically, a groove 16 with a radius smaller than the circular trajectory radius of the installation opening 12 is formed in the center of the surface of the fixed platform 10. The rotating shaft 17 is vertically fixed in the center of the groove 16. The upper end of the rotating shaft 17 is rotatably connected to the rotating platform 7 through a bearing. A fixed gear 18 is also fixed on the rotating shaft 17, the center of which is penetrated by the rotating shaft 17. A driving gear 19 meshing with the fixed gear 18 is provided in the groove 16. The deep-water motor 15 is fixed to the bottom surface of the rotating platform 7 and its driving shaft is connected to the center of the driving gear 19.

[0072] Among them: The deep-water motor 15 is generally a programmable underwater stepper motor, and the motor's start and stop time, speed, angle, direction and other parameters are set by computer software. This is a prior art, and the specific structure is not described in detail. In the present invention, the UN-NO-SE-02 programmable underwater stepper motor sold by Qingdao Lanchi Technology Co., Ltd. can be selected. It is a hydraulically compensated reduction stepper motor with a unique closed-loop control system that can accurately feedback the output angle of the main shaft. It has a built-in clock module and related control unit, and its working state can be set by supporting software. For example, by sending a command signal, it rotates from 0 degrees to 30 degrees at a fixed speed, and then cycles every 30 minutes to change the position of the sampling bottle to facilitate the continuous collection of seabed gas leakage.

[0073] The rotating platform 7 is provided with several mounting openings 12, which extend along the same circular trajectory and extend through the rotating platform 7. Inverted sampling bottles 4 are detachably mounted at the mounting openings 12 via spring-loaded locking buckles, allowing for quick and convenient replacement. The openings of the sampling bottles 4 are equipped with solenoid valves, and the sampling bottles 4 have built-in pressure and temperature sensors.

[0074] To facilitate the control of sampling bottles 4 for sampling, each sampling bottle 4 is evenly spaced on a circular trajectory. A corresponding number of mounting ports 12 can be provided based on the number of sampling bottles 4. The central angle between two adjacent sampling bottles 4 is 15°, 30°, 60°, etc. In this embodiment, the central angle between two adjacent mounting ports 12 is 30°, and a total of 12 mounting ports are provided to accommodate 12 sampling bottles 4. After a sampling bottle 4 completes its sampling task, the deep-water motor 15 controls the rotating platform to rotate 30°, allowing the next sampling bottle 4 to dock with the sampling port 20 for the next sampling.

[0075] After the device completes a collection task, it can be quickly put into the water again for collection by replacing the collection bottle 4 and installing the bottom counterweight seat 1, which greatly improves the efficiency of use. The opening of the sampling bottle 4 is equipped with a solenoid valve, and the sampling bottle 4 is used to store the collected gas samples. The bottle body is made of heat-insulating and pressure-resistant material, which can achieve heat-insulating and pressure-maintaining sampling. The number of sampling bottles 4 can be installed as needed. After the device completes a collection task, it can be quickly put into the water again for collection by replacing the sampling bottle 4 and installing the bottom counterweight seat 1, which greatly improves the efficiency of use.

[0076] The fixed platform 10 has a sampling port 20 extending through it, directly below the circular trajectory of the mounting port 12. The bottom surface of the fixed platform 10 is connected to the gas capture device 9 at the sampling port 20. An electric control valve is also installed within the sampling port 20 at the connection with the gas capture device 9. The electric control valve is installed at the junction between the sampling port 20 of the sampling bottle 4 and the gas outlet of the gas capture device 9. It is connected to the gas outlet via 316L stainless steel screws. The opening and closing degree of the electric control valve determines the size of the gas outlet, thereby controlling the sampling speed, avoiding chemical reactions of the water-gas mixture caused by volume changes, ensuring sample quality, and achieving high-fidelity sampling.

[0077] The gas capturer 9 includes an outer shell and a gas separation module arranged in the outer shell. The lower part of the outer shell of the gas capturer 9 is provided with an air inlet 21, and the upper part is provided with an air outlet 22. The air inlet 21, the gas separation module, and the air outlet 22 together form a gas flow channel for the entry of the water-gas mixture; the gas separation module includes a separation section composed of a polymer multilayer separation membrane structure 24 and a centrifugal impeller 23. The polymer multilayer separation membrane structure 24 is arranged near the air outlet 22, and a multilayer membrane structure formed by polymer separation membranes of different pore sizes is arranged therein. The outer layer of the multilayer membrane structure is a large-pore membrane, and the inner layer is a small-pore membrane, and the pore size of the membrane decreases successively from the outer layer to the inner layer; the centrifugal impeller 23 is arranged near the air inlet. It is a rotating blade driven by an electromagnetic drive device 25, which is used to drive the water-gas mixture into the separation section, and the separation section is used for step-by-step separation of water and gas.

[0078] The centrifugal impeller 23 generates centrifugal force through high-speed rotation, effectively accelerating the gas flow, separating particles and liquid droplets, and improving gas separation efficiency. The electromagnetic drive device utilizes electromagnetic force to drive the centrifugal impeller. The electromagnetic coil, coupled to the rotor shaft, precisely controls the impeller's rotational speed, thereby regulating the airflow speed and centrifugal force. The centrifugal impeller and the electromagnetic drive device are connected via the rotor shaft. The electromagnetic force is transmitted to the rotor shaft, driving the centrifugal impeller's rotation.

[0079] Connected between the bottom of the inner cavity 13 and the bracket 11 is a counterweight base 1, which can be separated from the bracket 11 by an acoustic release controlled by an electromagnetic fuse. The counterweight base 1 is provided with an opening for seabed gas to enter the inner cavity 13. After the bottom counterweight base 1 is released, the device detaches from the counterweight base 1, allowing the device to automatically float. The weight of the counterweight base 1 is calculated to ensure that the total underwater weight of the device is approximately 100 kg after overcoming the buoyancy of the buoyant block 2. After the counterweight is released, the buoyant block containing the floating material provides buoyancy for the entire device, ensuring a floating speed of approximately 1 m / s.

[0080] Bracket 11 is a 316L stainless steel frame structure, encased in a buoyant block 2 made of buoyant material. Both are connected using 316L stainless steel screws. The bottom counterweight 1 is a disposable cement structure with a lifting ring. This ring is connected to the upper acquisition device via a fusible link. The fusible link passes through the lifting ring and connects to the underwater acoustic releaser. The underwater acoustic releaser is connected to bracket 11 using a clamp and screws. This is mature commercial technology, and EdgeTech's fusible underwater acoustic releaser product is suitable.

[0081] The rotating platform 7 is equipped with an underwater acoustic transducer 5 at the center of the circular track of the installation port 12, and the bottom surface of the fixed platform 10 is equipped with a control cabin 8. The control cabin 8 is equipped with a controller and a lithium battery pack for power supply. The output end of the controller is electrically connected to the deep-water motor 15, the solenoid valve and the acoustic releaser respectively, and the input end of the controller is electrically connected to the underwater acoustic transducer 5. The underwater acoustic transducer 5 can communicate wirelessly with the control system of the surface vessel.

[0082] The lithium battery pack within the control cabin 8 provides long-term power for the device, ensuring it can operate for extended periods without an external power source. The battery pack and circuit design ensure the device can operate continuously at extreme depths and in harsh environments, improving system reliability and endurance. Sensors are also mounted on the bottom of the control cabin. These sensors are connected to the controller and lithium battery pack inside the cabin via cables. The lithium battery pack powers the sensors, while the controller controls the sensor's acquisition start and end times, as well as the sampling frequency.

[0083] The device bracket 11 and connectors of the present invention are all made of 316L stainless steel and can be replaced with titanium alloy according to collection requirements, thereby meeting the maximum seabed gas seepage capture requirements of 6000m.

[0084] All key components of this device, such as the sampling bottle 4, rotating platform 7, and deepwater motor 15, have been carefully designed to withstand the harsh high-pressure, low-temperature environment of the deep sea. The device's external structure and internal components are made of corrosion-resistant materials, such as 316L stainless steel or titanium alloy, to ensure long-term reliable operation in deep-sea environments.

[0085] Combined with precise control of the hydroacoustic transducer 5 and the deepwater motor 15, the device can adaptively adjust sampling based on real-time data. During the sampling process, the device can automatically adjust the sampling frequency and time interval based on parameters such as the type and concentration of the collected gas, ensuring the accuracy and representativeness of the data.

[0086] An in-situ monitoring method using a time series deep seabed gas leakage capture device comprises the following steps:

[0087] S1. Deployment:

[0088] S11. Preparation before deployment: After confirming that all components in the device are working normally, the manipulator of the underwater robot (ROV) grasps the guardrail on the top of the device and brings the entire device to a stable deployment depth.

[0089] S12. Positioning and deployment: The ROV uses an underwater camera to determine the exact location of the seabed gas leak, ensuring that the device is directly above the leak point. The manipulator slowly releases the device to the seabed so that the device covers the gas leak point.

[0090] S2. Collection:

[0091] S21. Activating the device: After the device is deployed, it receives an activation command from a surface vessel through the underwater acoustic transducer 5. The underwater acoustic transducer 5 is connected to the vessel's communication system in real time to ensure accurate transmission of the command.

[0092] S22, timed sampling: the device automatically opens the solenoid valve at a preset time interval to start the sampling process. The automatic control of the solenoid valve ensures that the leaked gas mixed with seawater samples are accurately collected within the set time. The collection bottle 4 is filled with a certain amount of sample each time.

[0093] S23. Sample replacement: After completing one sample collection, the solenoid valve automatically closes to prevent more seawater from entering the sampling bottle 4. The deep-water motor 15 drives the rotating platform 7 to rotate a preset angle so that the second sampling bottle 4 is aligned with the sampling port and docked with the gas capturer 9. Each sampling bottle 4 completes the sample exchange at the set angle.

[0094] S24, repeated sampling: The device completes sampling from all sample bottles 4 in sequence. After each sampling bottle 4 completes its task, the device enters a silent state until the next sampling time point. The silent state helps save power, extend the device's operating time, and avoid unnecessary energy consumption.

[0095] S25. High-precision time control: Accurately control the time of each sampling task, keep the time interval between each sampling point consistent, and obtain accurate time series data.

[0096] The underwater acoustic transducer 5 of the device starts working after receiving a command sent by the surface ship. After the device starts working, it automatically opens the solenoid valve according to the time interval set at the beginning of the device to collect seawater samples containing leaked gas in the inner cavity 1. After the preset collection time is reached, the solenoid valve automatically closes, and the deep-water motor 15 drives the rotating platform 7 to rotate the preset angle, so that the second collection bottle 4 docks with the gas capturer 9 at the collection port, waiting for the next collection time point, and starts repeating the above steps to complete the collection of all sample bottles in sequence.

[0097] The gas leakage rate Q can be calculated in real time when the sampling bottle is collecting gas, realizing long-term series observation. The formula is as follows:

[0098]

[0099]

[0100] Where: ΔP is the change in gas pressure, V is the effective volume of the sampling bottle, T is the ambient temperature, R is the ideal gas constant, Δt is the sampling time interval, k filter is the multi-stage filtration membrane pass rate coefficient, k centrifge is the centrifugal separation efficiency coefficient, Q in is the gas flow rate at the centrifugal impeller inlet, Q out is the gas flow rate at the centrifugal impeller outlet, T i is the transmittance of the ith filter membrane, and n is the number of filter membrane stages.

[0101] Δt is recorded by the sampling module through the built-in clock of the control system to calculate the time difference; ΔP is recorded by the high-precision pressure sensor in the sampling bottle to record the gas pressure change before and after sampling; V uses the calibration data V nominal And corrected according to the high pressure environment on the seabed:

[0102]

[0103] K is the bulk modulus of the sampling bottle material.

[0104] k centrifge The calculation is done by installing flow sensors at the inlet and outlet of the centrifugal module to measure Q in and Q out ;k filter The calculation is done by recording the transmittance T of the filter membrane step by step. i , calculated by the total formula.

[0105] In the laboratory, k centrifge Direct determination was performed to calculate k under different experimental conditions. centrifuge , draw a function curve of efficiency as a function of parameter changes; select the parameter range closest to the on-site environment, and extract the corresponding efficiency value as a fixed coefficient. Reduce on-site complexity: There is no need to install flow sensors and measurement modules on-site, reducing equipment complexity and potential failure points. Improve measurement accuracy: Accurate measurements under laboratory conditions can avoid the impact of interference such as pressure and temperature in deep-sea environments on the data. Reduce maintenance costs: There is no need to regularly calibrate on-site sensors, reducing the maintenance frequency and cost of equipment. Optimize the calculation model: Laboratory measured data can be directly used to build a more stable leakage rate calculation model.

[0106] S3. Recycling:

[0107] S31. Triggering the recovery command: After the sampling task is completed, the surface vessel sends a release command through the hydroacoustic transducer 5 to trigger the recovery process of the device. After receiving the release command, the controller controls the acoustic releaser to activate the fuse function.

[0108] S32. Counterweight Release and Ascent: Upon receiving the command, the acoustic releaser energizes and quickly blows the fuse, separating the device from counterweight base 1. This separation causes the device to immediately begin ascending, with the buoyancy system ensuring a stable ascent. The controller tracks the device's ascent in real time and reports its depth and progress to the surface vessel via underwater acoustic communication.

[0109] S33. Ascent and Recovery: The device automatically ascends at a speed of approximately 1 meter per second, eventually surfacing. The recovery process is completely automated, requiring no ROV assistance. Remote communication between the hydroacoustic transducer 5 and a surface vessel allows the vessel to prepare for recovery based on the device's real-time location, minimizing manual labor and reducing costs.

[0110] S34, Post-recovery Operations: After recovering to the surface, the staff can inspect the device, quickly replace the sampling bottle 4 and the bottom counterweight 1, and conduct a brief debugging and inspection. The device is ready for deployment again at any time, thus achieving a rapid deployment and recovery cycle and improving the efficiency of submarine gas leakage collection tasks.

[0111] A release command is sent through a surface vessel. After the device receives the release command through the underwater acoustic transducer 5 on the seabed, the controller sends a fuse command to the electromagnetically fused acoustic releaser. After the releaser is energized, the fuse is blown, and the device is separated from the counterweight and automatically floats up. The controller sends distance data in real time during the floating process until it floats to the sea surface.

[0112] After the device is recovered, the sampling bottle 4 and bottom counterweight 1 can be quickly replaced and then quickly redeployed. To capture multiple subsea gas leaks, multiple collection devices can be deployed sequentially using an ROV and retrieved several months later. This device relies only on an ROV for precise placement during deployment, but not for retrieval. This is an advantage over similar devices currently available, significantly reducing observation costs.

[0113] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by adopting existing technologies, which will not be described here. The above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A time series deep seabed leakage gas capture device, comprising a bracket, characterized in that: The bracket is connected to the float block through external wrapping, and an inner cavity for accommodating leaked gas is formed inside the bracket. A fixed platform is sealed and connected between the float block and the bracket on the top of the inner cavity. A rotating platform driven by a deep-water motor is rotatably installed on the fixed platform. The rotating platform is provided with several mounting ports located on the same circular track and passing through the rotating platform, and an inverted sampling bottle is detachably installed at the mounting port. The opening of the sampling bottle is provided with a solenoid valve, and the sampling bottle has a built-in pressure and temperature sensor. The fixed platform is provided with a sampling port passing through the fixed platform directly below the circular track of the mounting port. A gas capturer is connected to the sampling port on the bottom of the fixed platform, and an electric control valve is also installed in the sampling port at the connection with the gas capturer; after a sampling bottle completes the sampling task, the deep-water motor controls the rotating platform to rotate 30 degrees, so that the next sampling bottle is docked with the sampling port for the convenience of the next sampling; the bracket is connected to the bottom of the inner cavity There is a counterweight seat that can be separated from the bracket by an acoustic releaser, and a hole is provided on the counterweight seat for seabed gas to enter the inner cavity; the gas capturer includes an outer shell and a gas separation module arranged in the outer shell, the lower part of the outer shell of the gas capturer is provided with an air inlet, and the upper part is provided with an air outlet, and the air inlet, the gas separation module and the air outlet together form a gas flow channel for the entry of the water-gas mixture; the gas separation module includes a separation section composed of a polymer multi-layer separation membrane structure and a centrifugal impeller, the polymer multi-layer separation membrane structure is arranged near the air outlet, and a multi-layer membrane structure formed by polymer separation membranes of different pore sizes is arranged therein, the outer layer of the multi-layer membrane structure is a large-pore membrane, and the inner layer is a small-pore membrane, and the pore size of the membrane decreases successively from the outer layer to the inner layer; the centrifugal impeller is arranged near the air inlet, and is a rotating blade driven by an electromagnetic drive device, which is used to drive the water-gas mixture into the separation section, and the separation section is used for step-by-step separation of water and gas.

2. The time series deep seabed leakage gas capture device according to claim 1 is characterized in that: A hydroacoustic transducer is installed at the center of the circular track of the installation port of the rotating platform, and a control cabin is installed on the bottom of the fixed platform. A controller and a lithium battery pack for power supply are set in the control cabin. The output end of the controller is electrically connected to the deep-water motor, solenoid valve and acoustic releaser respectively, and the input end of the controller is electrically connected to the hydroacoustic transducer. The hydroacoustic transducer can communicate wirelessly with the control system of the surface vessel.

3. The time series deep seabed leakage gas capture device according to claim 1 is characterized in that: The center of the surface of the fixed platform is concavely formed with a groove with a radius smaller than the radius of the circular trajectory of the installation port. The rotating shaft is vertically fixed in the center of the groove. The upper end of the rotating shaft is rotatably connected to the rotating platform through a bearing. A fixed gear with the center penetrated by the rotating shaft is also fixed on the rotating shaft. A driving gear meshing with the fixed gear is provided in the groove. The deep-water motor is fixed to the bottom surface of the rotating platform and its driving shaft is connected to the center of the driving gear.

4. The time series deep seabed leakage gas capture device according to claim 1, characterized in that: The bracket is also connected to a plurality of handles extending out of the floating block in the circumferential direction of the side surface. A gas release port is provided at each handle, and the position of the gas release port is higher than the gas collection inlet.

5. The time series deep seabed leakage gas capture device according to claim 1 is characterized in that: The collecting bottle is detachably connected to the rotating platform through a spring locking buckle.

6. The time-series deep-sea bottom leakage gas capture device according to claim 1, characterized in that: The upper end of the bracket passes through the fixed platform to form a guardrail arranged around the circumference of the rotating platform.

7. An in-situ monitoring method using the time series deep seabed gas leakage capture device according to claim 1, characterized in that: The following steps are involved: S1. Deployment: S11. Preparation before deployment: After confirming that all components in the device are working properly, the manipulator of the underwater robot (ROV) grasps the guardrail on the top of the device and brings the entire device to a stable deployment depth; S12. Positioning and deployment: The ROV uses an underwater camera to determine the exact location of the seabed gas leak and ensures that the device is directly above the leak point. The manipulator slowly releases the device to the seabed, ensuring that the device covers the gas leak point. S2. Collection: S21. Activation device: After the device is deployed, it receives activation commands from a surface vessel via an underwater acoustic transducer. The underwater acoustic transducer and the vessel's communication system are connected in real time to ensure accurate transmission of commands. S22. Timed sampling: The device automatically opens the solenoid valve at a preset time interval to start the sampling process. The automatic control of the solenoid valve ensures that the leaked gas mixed with seawater samples are accurately collected within the set time, and the collection bottle is filled with a certain amount of sample each time; S23. Sample replacement: After completing one sample collection, the solenoid valve automatically closes to prevent more seawater from entering the sampling bottle. The deepwater motor drives the rotating platform to rotate to a preset angle so that the second sampling bottle is aligned with the sampling port and docked with the gas capture device. Each sampling bottle completes the sample exchange at the set angle; S24, repeated sampling: completing the collection of all sample bottles in sequence, after completing the task of each sampling bottle; S25, High-precision time control: Precisely control the time of each sampling task, keep the time interval between each sampling point consistent, and obtain accurate time series data; S3. Recycling: S31. Triggering the recovery command: When the sampling task is completed, the surface vessel sends a release command through the underwater acoustic transducer to trigger the recovery of the device. After receiving the release command, the controller controls the acoustic releaser to activate the fuse function; S32. Counterweight release and ascent: Upon receiving the command, the acoustic releaser is energized and the fuse is quickly blown. The device separates from the counterweight base and begins to ascend. The controller tracks the ascent process of the device in real time and transmits the real-time depth and ascent progress to the surface vessel via underwater acoustic communication. S33, Floating and Recovery: The device rises at a floating speed of 1 meter per second and surfaces; S34. Post-recovery operation: After recovery to the water surface, the staff can check the device, quickly replace the sampling bottle and the bottom weight, and be ready to deploy again after debugging and inspection to achieve cyclic deployment and recovery.

8. The in-situ monitoring method according to claim 7, characterized in that: After completing each sampling task of a collection bottle, the device enters a silent state until the next sampling time point ends the silent state.

9. The in-situ monitoring method according to claim 7, characterized in that: In step S2, the gas leakage rate can be measured when the sampling bottle is collecting gas. Q Perform real-time calculations to achieve long-term series observations. The formula is as follows: ； ； ； in: ΔP is the change in gas pressure, V is the effective volume of the sampling bottle, T is the ambient temperature, R is the ideal gas constant, Δ t is the sampling time interval, k filter is the multi-stage filtration membrane pass coefficient, k centrifge is the centrifugal separation efficiency coefficient, Q in is the gas flow rate at the centrifugal impeller inlet, Q out is the gas flow rate at the centrifugal impeller outlet, T i For the i The transmittance of the first filter membrane, n is the number of filtration membrane stages.

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