Equipment and method for solidifying and storing carbon dioxide in artificial submarine hydrate reservoirs

Abstract

The present invention relates to the field of carbon dioxide seabed storage, and in particular to equipment and methods for using seabed artificial hydrate reservoirs to solidify and store carbon dioxide. The technical solution is as follows: a transport ship is connected to a hydrate seabed slurry integration core system through a carbon dioxide injection riser and a surfactant injection riser, a mud seabed collection system is provided on one side of the transport ship, and a mixed slurry output system is provided on the other side; a mud slurry is formed by the mud seabed collection system, and the surfactant, mud slurry and seawater are pumped into a carbon dioxide hydrate generating seabed mixer and continuously stirred to form a carbon dioxide hydrate-mud mixed slurry, which is transported to a seabed depression through a mixed slurry output system; an artificial carbon dioxide reservoir is formed by covering the mud layer, thereby realizing safe seabed storage of carbon dioxide. This solves the problems of traditional carbon dioxide seabed storage methods that rely on formation traps and structures, are limited in storage scale, and are prone to leakage after long-term storage.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide seabed storage, and in particular to equipment and a method for using seabed artificial hydrate reservoirs to solidify and store carbon dioxide. Background Art

[0002] Currently, in the process of carbon dioxide storage, the common carbon dioxide storage technologies are as follows:

[0003] 1. Geological storage: This method mimics the natural storage mechanism of fossil fuels by injecting carbon dioxide into deep geological formations. The basic principle is to use the physical sealing and chemical stability of geological structures to store carbon dioxide. Once injected underground, carbon dioxide interacts with the surrounding rocks and fluids, achieving long-term stable storage through various mechanisms.

[0004] 2. Mineralization storage: This method uses a chemical reaction between CO2 and specific minerals (such as basalt and olivine) to form stable carbonate minerals, thereby permanently fixing CO2. This method of storage is based on the principle of natural weathering. By artificially accelerating the carbonation reaction of minerals, CO2 is converted into solid minerals, eliminating the risk of CO2 leakage. However, the reaction speed of mineralization storage is relatively slow and requires a large amount of mineral resources. It is currently still in the research and demonstration stage.

[0005] 3. Ocean storage: Utilizing the vast volume of the ocean and the high solubility of carbon dioxide in water, the ocean becomes a container for storing carbon dioxide. The total amount of carbon contained in seawater is about 50 times that of the atmosphere, and the ocean has a huge potential for carbon sequestration. After carbon dioxide is injected into the deep sea, it will dissolve in the seawater and gradually be sealed in the deep sea water as the seawater circulates. However, ocean storage technology has some potential environmental risks, such as increasing the acidity of seawater and causing adverse effects on marine life. At present, ocean storage technology is still in the research and testing stage and has not yet been applied on a large scale;

[0006] 4. Biosequestration: Carbon dioxide is fixed through photosynthesis or biochemical reactions in organisms. Organisms (such as plants and algae) use carbon dioxide for growth and metabolism, converting it into organic matter, thereby fixing it. However, biosequestration relies entirely on the number and scale of plants and algae, resulting in low efficiency and limited potential, making it difficult to use as the primary means of carbon dioxide storage.

[0007] According to current research and practical experience, among the above-mentioned technical means, geological storage technology is recognized as one of the most promising methods of carbon dioxide storage. Geological structures suitable for carbon dioxide storage exist both on land and on the seabed. Seabed geological storage of carbon dioxide combines the advantages of geological storage and marine storage. The seabed geological structure is far away from the terrestrial aquifer and has the pressure and barrier of rock cover and surface seawater. Compared with land storage, seabed geological storage of carbon dioxide has the advantages of large storage potential, no occupation of land resources, and less impact on human health and safety.

[0008] Common submarine geological storage technologies include submarine saline aquifer storage, submarine oil and gas reservoir storage, submarine basalt storage, submarine hydrate storage, and submarine supercritical CO2 storage. Each of these technologies has its own advantages, but they all share common disadvantages and limitations. The complex geological conditions of submarine saline aquifers, such as porosity, permeability, and caprock integrity, make it difficult to ensure long-term and stable CO2 storage. The geological conditions of submarine oil and gas reservoirs are also very complex, with the potential for cracks and faults, increasing the risk of CO2 leakage. Their storage capacity is relatively limited, and their potential is relatively low. The porosity of submarine basalt layers is relatively low, resulting in high CO2 injection resistance. The reaction process for CO2 storage in basalt is complex, resulting in low storage efficiency and poor stability. Subsea hydrate storage has some potential, but the formation and decomposition of CO2 hydrates are difficult to monitor and control during implementation in deepwater environments. Furthermore, the complex geological structure of the seabed can affect long-term storage, leading to the risk of decomposition or leakage. The compression and transportation of supercritical CO2 require advanced technology and equipment, resulting in high costs. Furthermore, the long-term stability of supercritical CO2 in geological structures is unknown.

[0009] In summary, existing submarine CO2 storage technologies rely heavily on geological traps and structures, limiting their scale. Furthermore, CO2 exists as a gas or liquid during storage, making it susceptible to leakage over extended periods. Summary of the Invention

[0010] The purpose of the present invention is to address the above-mentioned defects of the existing technology and provide an equipment and method for solidifying and storing carbon dioxide in an artificial submarine hydrate reservoir, which solves the problems that traditional submarine carbon dioxide storage methods rely on formation closures and structures, are limited in storage scale, and are prone to leakage after long-term storage.

[0011] The equipment for solidifying and sealing carbon dioxide in artificial submarine hydrate reservoirs mentioned in the present invention has the following technical solutions: it includes a transport ship and a liquid carbon dioxide storage tank, and also includes a surfactant storage tank, a carbon dioxide injection pump, a carbon dioxide injection riser, a surfactant injection pump, a surfactant injection riser, a hydrate submarine slurry integrated core system, a mud submarine collection system and a mixed slurry output system. The bottom of the transport ship is connected to the hydrate submarine slurry integrated core system on the submarine formation through a carbon dioxide injection riser and a surfactant injection riser. A mud submarine collection system is provided on one side of the hydrate submarine slurry integrated core system, and a slurry collecting system is provided on the other side. Mixed slurry output system: inject carbon dioxide and surfactants from the transport ship into the integrated core system of seabed hydrate mixing through the carbon dioxide injection riser and the surfactant injection riser, form mud slurry through the mud seabed collection system, pump the surfactant, mud slurry and seawater into the carbon dioxide hydrate generating seabed mixer and continuously stir, and use the high pressure of the seabed and the low temperature of seawater as driving force to form carbon dioxide hydrate-mud mixed slurry, and transport the carbon dioxide hydrate-mud mixed slurry to the seabed depression through the mixed slurry output system; then form an artificial carbon dioxide reservoir by covering the mud layer to achieve safe seabed storage of carbon dioxide.

[0012] Preferably, the above-mentioned hydrate seabed mixing integrated core system is composed of a carbon dioxide hydrate generating seabed mixer, a surfactant injection submodule, a mud slurry injection submodule, a seawater injection submodule, and a mixed slurry output submodule, which are installed in combination on the upper side of the core bearing and mobile submodule. The position is moved by the core bearing and mobile submodule. One side of the carbon dioxide hydrate generating seabed mixer is connected to the mud slurry injection submodule through the mud injection port, and is connected to the surfactant injection submodule through the surfactant injection port. The other side of the carbon dioxide hydrate generating seabed mixer is connected to the seawater injection submodule through the seawater injection port, and the mixed slurry output submodule is connected at the bottom of the carbon dioxide hydrate generating seabed mixer.

[0013] Preferably, the above-mentioned carbon dioxide hydrate generation seabed mixer is divided into a mixer stirring functional area, a mixer separation functional area and a mixer output functional area; the top of the mixer stirring functional area is provided with a carbon dioxide injection port, the outer wall of the lower half of the left end is embedded with a mud injection port and a surfactant injection port, and the outer wall of the lower half of the right end is embedded with a seawater injection port; the inner wall of the mixer stirring functional area is provided with a mixing and stirring device, which consists of a stirring rotary motor, a vertical rotating rod and a horizontal rotating rod, and each horizontal rotating rod is equipped with a plurality of trapezoidal stirring blades; the inner wall of the carbon dioxide hydrate generation seabed mixer is distributed with a plurality of mixer temperature and pressure sensors, and a mixer bracket is provided at the lower outer part to leave sufficient space at the bottom to realize the connection between the mixed slurry output horizontal straight pipe and the bottom of the right inner wall of the mixer output functional area; the core bearing and moving submodule includes core system crawler wheels, a core system bearing base and a drag hook, the bottom of the core system bearing base is provided with multiple sets of core system crawler wheels, and drag hooks are provided at both ends of the core system bearing base.

[0014] Preferably, the above-mentioned surfactant injection submodule consists of a surfactant stirring storage tank, a surfactant delivery straight pipe, and a surfactant delivery pump. The top of the surfactant stirring storage tank is provided with a surfactant riser injection port, which is connected to the surfactant injection riser; the inner wall of the surfactant stirring storage tank is equipped with a surfactant stirring device, and the inner wall of the surfactant stirring storage tank is provided with a tank temperature and pressure sensor, and the bottom is connected to the carbon dioxide hydrate generating seabed mixer through the surfactant delivery straight pipe and the surfactant delivery pump.

[0015] Preferably, the above-mentioned mud slurry injection submodule consists of a mud conveying telescopic hose, a mud conveying hose retractor, a mud conveying vertical straight pipe, a secondary mud conveying pump bracket, a secondary mud conveying pump, and a mud conveying horizontal straight pipe. The output end of the secondary mud conveying pump is connected to the carbon dioxide hydrate generating seabed mixer through the mud conveying horizontal straight pipe; the secondary mud conveying pump bracket, the mud conveying vertical straight pipe and the mud conveying hose retractor are installed on the lower side of the secondary mud conveying pump, and the distance and relative position between the mud seabed collection system and the hydrate seabed mixing integrated core system are controlled by the mud conveying telescopic hose and the mud conveying hose retractor.

[0016] Preferably, the above-mentioned seawater injection submodule consists of a seawater suction inlet, a solid filtering device, a filtering device bracket, a seawater suction horizontal straight pipe, a seawater suction pump, and a seawater suction pump bracket. The output end of the seawater suction pump is connected to the carbon dioxide hydrate generating seabed slurry mixer, and the input end of the seawater suction pump is connected to the seawater suction inlet through the seawater suction horizontal straight pipe and the solid filtering device. The filtering device bracket is installed on the lower side of the solid filtering device, and the seawater suction pump bracket is installed on the lower side of the seawater suction pump.

[0017] Preferably, the above-mentioned mixed slurry output submodule consists of a mixed slurry output horizontal straight pipe, a first-level mixed slurry output pump, a mixed slurry output hose telescopic device, and a mixed slurry output telescopic hose. The input end of the first-level mixed slurry output pump is connected to the carbon dioxide hydrate generation seabed mixer through the mixed slurry output horizontal straight pipe, and the output end of the first-level mixed slurry output pump is connected to the mixed slurry output system through the mixed slurry output hose telescopic device and the mixed slurry output telescopic hose.

[0018] Preferably, the above-mentioned mud seabed collection system consists of a sediment impactor, a mud collector, a mud suction pipe, a mud suction pump and a solid filtering device, a mud suction port, a mud stirring storage tank, a mud stirring device, a mud storage tank temperature and pressure sensor, a small seawater suction pump and a solid filtering device, a mud delivery straight pipe, a first-level mud delivery pump, a mud delivery retractable hose, a collection system crawler wheel, a collection system supporting base, a collection system mobile controller, and a small seawater suction port. The bottom of the collection system supporting base is provided with a collection system crawler wheel, and the upper side of the collection system supporting base is provided with a mud stirring storage tank. The top of the mud stirring storage tank is connected to the small seawater suction inlet through a small seawater suction pump and a solid filtering device. The mud suction pump, the solid filtering device and the collection system mobile controller are provided on the left side of the mud stirring storage tank. The outer sides of the mud suction pump and the solid filtering device are connected to the mud collector through a mud suction pipe. A mud impactor is installed on the lower side of the mud collector; the right side of the mud stirring storage tank is connected to the first-level mud delivery pump through a mud delivery straight pipe, and the outer end of the first-level mud delivery pump is connected to the mud and sand slurry injection sub-module through a mud delivery retractable hose; the mud stirring device is installed in the inner cavity of the mud stirring storage tank.

[0019] Preferably, the above-mentioned mixed slurry output system includes a mixed slurry output retractable hose, a secondary mixed slurry output pump, an extendable hose in front of the mixed slurry discharge pipe, a mixed slurry discharge pipe lifter, a mixed slurry discharge pipe, a mixed slurry discharge guide plate, an output system track wheel, an output system supporting base and an output system mobile controller. The output system track wheel is installed on the lower side of the output system supporting base, and the secondary mixed slurry output pump and the output system mobile controller are installed on the upper side. The left end of the secondary mixed slurry output pump is connected to the mixed slurry output retractable hose, and the right end is connected to the mixed slurry discharge pipe through the extendable hose in front of the mixed slurry discharge pipe. A mixed slurry discharge guide plate is provided on the lower side of the mixed slurry discharge pipe, and the carbon dioxide hydrate-sediment mixed slurry is transported to the seabed depression through the mixed slurry discharge pipe and the mixed slurry discharge guide plate.

[0020] In addition, the method for using the equipment for solidifying and storing carbon dioxide in the artificial submarine hydrate reservoir mentioned in the present invention is technically divided into four stages: continuous injection stage, hydrate generation and slurry mixing stage, mixed slurry discharge stage, and sediment layer covering stage;

[0021] First, in the continuous injection phase, liquid carbon dioxide and surfactants on the transport ship, mud slurry formed in the seabed formation, and low-temperature seawater near the seabed need to be injected into the seabed mixer for carbon dioxide hydrate generation in sequence. The main steps include:

[0022] a1. Preparation before system deployment: Before deploying all equipment to the seabed formation, the pressure in the CO2 hydrate generation seabed mixer, mud mixing tank, and surfactant mixing tank should be 0 MPa and kept completely sealed;

[0023] a2. Deployment of the system to the seabed: The integrated hydrate subsea slurry mixing core system, the mud subsea collection system, and the mixed slurry output system are lowered to the seabed formation at a water depth of 800 to 2000 meters according to the location of different seabed depressions; the seabed anchoring devices installed on the core system's track wheels are inserted into the seabed formation, and the carbon dioxide injection pump and surfactant injection pump on the transport vessel are connected to the carbon dioxide injection port and the surfactant riser injection port respectively through the carbon dioxide injection riser and the surfactant injection riser; the mud subsea collection system is moved to a position near the integrated hydrate subsea slurry mixing core system via the collection system movement controller, and the seabed anchoring devices installed on the collection system's track wheels are inserted into the seabed formation; the mixed slurry output system is moved to a position near the seabed depression via the output system movement controller, and the seabed anchoring devices installed on the output system's track wheels are inserted into the seabed formation;

[0024] a3. Surfactant injection and cooling: Open the ball valve in the surfactant riser injection port and inject surfactant into the surfactant stirring tank. Simultaneously, start the surfactant stirring device. When the pressure in the surfactant stirring tank approaches the pressure at the seabed, stop injection and close the ball valve in the surfactant riser injection port. Continue stirring to accelerate the heat exchange process between the surfactant and the low-temperature seawater through the outer wall of the surfactant stirring tank.

[0025] a4. Collection and dilution of seabed mud slurry: While the surfactant injection and cooling steps are in progress, the mud impactor in the mud seabed collection system is used to disperse and lift the mud in the seabed formation to initially form mud with seawater. Simultaneously, the ball valve, mud pump, solid filter device, small seawater pump, solid filter device, and mud stirring device in the mud suction port are opened to pump the initially formed mud and seawater on the seabed into the mud stirring tank and continuously stir. The pressure is monitored by the mud tank temperature and pressure sensor. When the pressure in the mud stirring tank reaches the pressure value at the seabed, all pumps and ball valves in the mud seabed collection system are closed.

[0026] a5. Injecting carbon dioxide: When the temperature of the surfactant in the surfactant stirring tank drops below the carbon dioxide hydrate phase equilibrium temperature corresponding to the seabed pressure, open the ball valve in the carbon dioxide injection port to inject liquid carbon dioxide into the carbon dioxide hydrate generating seabed slurry mixer. Simultaneously, start the slurry stirring device. When the internal pressure reaches 0.8 times the seabed pressure, stop the injection and close the ball valve in the carbon dioxide injection port.

[0027] a6. Injecting low-temperature surfactant: Start the surfactant delivery pump, open the ball valve in the surfactant injection port, and inject the surfactant into the CO2 hydrate generation submarine slurry mixer, while keeping the surfactant stirring device and the slurry stirring device open. When the injection volume reaches the design standard, stop the injection and close the ball valve in the surfactant injection port and the surfactant delivery pump;

[0028] a7. Injection of mud slurry: Start the primary mud delivery pump and the secondary mud delivery pump, open the ball valve in the mud injection port, and deliver the mud slurry with reduced mud concentration after being diluted with seawater to the CO2 hydrate generation seabed mixer. At the same time, keep the mud stirring device and the slurry mixing device open to avoid mud deposition. When the injection volume reaches the design standard, stop the injection and close the ball valve in the mud injection port, the primary mud delivery pump, and the secondary mud delivery pump;

[0029] a8. Inject low-temperature seawater: Confirm that the ball valve at the tail end of the liquid recovery retractable hose is closed, open the ball valve of the seawater inlet vertical pipe, start the seawater inlet pump, open the ball valve in the seawater injection port, and inject low-temperature seawater near the seabed that has been filtered through solids into the carbon dioxide hydrate generation seabed mixer. At the same time, start the mixing device. When the injection volume reaches the design standard, stop the injection and close the ball valve in the seawater injection port, the seawater inlet pump, and the ball valve of the seawater inlet vertical pipe;

[0030] Second, in the hydrate formation and slurry mixing stage, the main steps are as follows:

[0031] b1. Hydrate formation: The rotation rate of the mixing and stirring device in the CO2 hydrate generation seabed mixer is increased, so that the CO2 in the high-seawater-content mud slurry stirring system reacts with seawater under the action of the high seawater pressure, low seawater temperature driving force, and surfactants to rapidly form CO2 hydrate. The temperature and pressure in different areas of the CO2 hydrate generation seabed mixer are monitored using multiple mixer temperature and pressure sensors, and an internally installed pressure-resistant high-definition camera lens is used to assist in observation. When a significant sudden temperature increase occurs, indicating the onset of CO2 hydrate formation, the hydrate formation amount is calculated based on the real-time changes in temperature and pressure.

[0032] b2. Formation of a CO2 hydrate-sediment mixed slurry by hydrates and sediment: When the temperature and pressure in various regions of the CO2 hydrate-generating seabed mixer no longer change significantly, the rotation rate of the mixing and stirring device is reduced. Under the influence of the surfactant, the hydrate particles and small hydrate aggregates are stirred with the sediment and seawater to gradually form a CO2 hydrate-sediment mixed slurry with good fluidity. By monitoring the feedback torque power of the mixing and stirring device, when the torque power no longer fluctuates significantly, it indicates that the properties and stirring state of the CO2 hydrate-sediment mixed slurry formed by the CO2 hydrate and sediment have stabilized.

[0033] Third, in the mixed slurry discharge stage, the main steps are as follows:

[0034] c1. Discharge of the mixed slurry: Maintain uniform rotation of the slurry mixing device to prevent the deposition of the carbon dioxide hydrate-sediment mixed slurry; adjust the mixed slurry discharge pipe lift to the lowest position, open the mixed slurry output pipe ball valve, start the first mixed slurry output pump and the second mixed slurry output pump, and discharge the carbon dioxide hydrate-sediment mixed slurry to the lowest level of the seabed depression. While discharging, adjust the mixed slurry discharge guide plate to ensure that the solid aggregates in the carbon dioxide hydrate-sediment mixed slurry are evenly deposited on the lowest level of the seabed depression; when the sediment is close to evenly filling the lowest level of the seabed depression, raise the mixed slurry discharge pipe lift to start discharging to a higher level of the seabed depression, and repeat this cycle until the seabed depression is nearly filled;

[0035] Fourth, in the sediment layer covering stage, the main steps are as follows:

[0036] d1. Injection of sediment slurry: Repeat the steps of collecting and diluting the seabed sediment slurry, injecting the low-temperature surfactant, injecting the sediment slurry, and injecting the seawater in the continuous injection phase to make the pressure in the carbon dioxide hydrate generation seabed mixer close to the pressure before the mixed slurry is discharged, while maintaining the uniform rotation speed of the mixing device;

[0037] d2. Discharge of sediment slurry: Pull out the seabed anchoring device on the track wheel of the output system, and discharge the sediment slurry by repeating the mixed slurry discharge step, but do not perform the liquid recovery step. While discharging the sediment slurry, adjust the position of the mixed slurry output system, the status of the mixed slurry discharge pipe lifter and the mixed slurry discharge guide plate in real time to ensure that the sediment is evenly deposited on all the carbon dioxide hydrate-sediment mixed solid sediments in the seabed depression. When the thickness of the overlying sediment layer reaches the coverage requirement of the hydrate-sediment mixed solid sediment in the depression area, stop all operations, close all pumps and ball valves in the system, and move the entire system to the vicinity of the next seabed depression.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] The present invention primarily utilizes an integrated subsea hydrate mixing core system, a subsea mud collection system, and a mixed slurry output system to achieve continuous injection of carbon dioxide, surfactants, subsea mud slurry, and low-temperature seawater into a subsea mixer for generating carbon dioxide hydrates. Utilizing the in-situ environmental conditions of high seabed pressure and low seawater temperature, the surfactant promotes formation and prevents deposition of a rapidly fluid carbon dioxide hydrate-mud mixed slurry. The mixed slurry is then transported to a subsea depression using a mixed slurry delivery system. Finally, the mud slurry is delivered to the target area to cover a certain thickness of mud layer, thereby forming an artificial carbon dioxide reservoir, thereby achieving safe subsea storage of carbon dioxide. The present invention addresses the issues of traditional subsea carbon dioxide storage methods, such as their extreme reliance on formation traps and structures, limited storage scale, and the tendency to leak after long-term storage. This invention has important theoretical and practical significance for optimizing efficient subsea carbon dioxide storage methods and controlling the long-term stability of sealed reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the overall system of the present invention;

[0041] Figure 2 This is a schematic diagram of the core structure of the integrated hydrate subsea slurry mixing system;

[0042] Figure 3 This is a schematic diagram of the integrated core system of hydrate seabed mixing;

[0043] Figure 4 It is a schematic diagram of the structure of the mud seabed collection system;

[0044] Figure 5 It is a structural diagram of the mixed slurry output system;

[0045] Figure 6This is a comparison of hydrate concentration and flow time in the seawater-mud slurry system in the experimental loop before and after adding surfactant CP;

[0046] In the figure: 1-transport ship, 2-liquid carbon dioxide storage tank, 3-surfactant storage tank, 4-carbon dioxide injection pump, 5-carbon dioxide injection riser, 6-surfactant injection pump, 7-surfactant injection riser, 8-hydrate seabed slurry integrated core system, 9-mud seabed collection system, 10-mixed slurry output system, 11-carbon dioxide hydrate-sediment mixed solid aggregate, 12-liquid not involved in hydrate formation, 13-seabed depression location, 14-seabed formation, 15-sea level, 16-carbon dioxide hydrate generation seabed mixer, 17-surfactant injection submodule, 18-sediment slurry injection submodule, 19-seawater injection submodule, 20-mixed slurry output submodule, 2 1- Core bearing and mobile submodule, 22- Core system crawler wheel, 23- Core system bearing base, 24- Drag hook, 25- Sediment impactor, 26- Mud collector, 27- Mud suction pipe, 28- Mud suction pump and solid filter device, 29- Mud suction port, 30- Mud mixing tank, 31- Mud stirring device, 32- Mud tank temperature and pressure sensor, 33- Small seawater suction pump and solid filter device, 34- Mud delivery straight pipe, 35- First-stage mud delivery pump, 36- Mud delivery retractable hose, 37- Collection system crawler wheel, 38- Collection system bearing base, 39- Collection system mobile controller, 40- Small seawater suction port, 41- Mud tank seawater suction port, 42 -Retractable hose for mixed slurry output, 43-Secondary mixed slurry output pump, 44-Extendable hose in front of mixed slurry discharge pipe, 45-Mixed slurry discharge pipe lifter, 46-Mixed slurry discharge pipe, 47-Mixed slurry discharge guide plate, 48-Output system track wheel, 49-Output system carrying base, 50-Output system movement controller, 51-Liquid recovery wide-mouth device, 52-Wide-mouth device tail baffle, 53-Liquid recovery vertical pipe, 54-Liquid recovery horizontal pipe, 55-Liquid recovery horizontal pipe bracket, 56-Liquid recovery pump, 57-Liquid recovery pump bracket, 58-Liquid recovery pump lifter, 59-Liquid recovery retractable hose, 60-Liquid recovery hose retractable device, 61-Liquid recovery hose retractable device Bracket, 62-Mixer stirring functional area, 63-Mixer separation functional area, 64-Mixer output functional area, 65-Carbon dioxide injection port, 66-Mud injection port, 67-Surfactant injection port, 68-Seawater injection port, 69-Mixer temperature and pressure sensor, 70-Mixer stirring device, 71-Stirring rotary motor, 72-Vertical rotating rod, 73-Horizontal rotating rod, 74-Trapezoidal stirring blade, 75-Pressure-resistant high-definition camera lens, 76-Mixer bracket, 77-Surfactant stirring tank, 78-Surfactant delivery straight pipe, 79-Surfactant delivery pump, 80-Surfactant riser injection port, 81-Surfactant stirring device, 82-Storage tank temperature and pressure sensor,83 - Mud delivery hose expansion joint, 84 - Mud delivery vertical pipe, 85 - Secondary mud delivery pump bracket, 86 - Secondary mud delivery pump, 87 - Mud delivery horizontal pipe, 88 - Seawater extraction port, 89 - Seawater extraction vertical pipe ball valve, 90 - Solids filter, 91 - Filter bracket, 92 - Seawater extraction horizontal pipe, 93 - Seawater extraction pump, 94 - Seawater extraction pump bracket, 95 - Liquid recovery retractable hose tail ball valve, 96 - Mixed slurry output horizontal pipe, 97 - Mixed slurry output pipe ball valve, 98 - First-stage mixed slurry output pump, 99 - Mixed slurry output hose expansion joint, 100 - Seabed anchoring device. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0048] Example 1, with reference to Figure 1-Figure 5 The equipment for solidifying and sealing carbon dioxide in artificial submarine hydrate reservoirs mentioned in the present invention includes a transport ship 1 and a liquid carbon dioxide storage tank 2, and also includes a surfactant storage tank 3, a carbon dioxide injection pump 4, a carbon dioxide injection riser 5, a surfactant injection pump 6, a surfactant injection riser 7, a hydrate submarine slurry integrated core system 8, a mud submarine collection system 9 and a mixed slurry output system 10. The liquid carbon dioxide storage tank 2 and the surfactant storage tank 3 are provided on the transport ship 1. The bottom of the transport ship 1 is connected to the hydrate submarine slurry integrated core system 8 on the submarine formation 14 through the carbon dioxide injection riser 5 and the surfactant injection riser 7. A mud slurry output system 10 is provided on one side of the hydrate submarine slurry integrated core system 8. The slurry seabed collection system 9 is provided with a mixed slurry output system 10 on the other side; the carbon dioxide and surfactant on the transport ship 1 are injected into the hydrate seabed mixing integrated core system 8 through the carbon dioxide injection riser 5 and the surfactant injection riser 7, and mud slurry is formed through the mud seabed collection system 9. The surfactant, mud slurry and seawater are pumped into the carbon dioxide hydrate generating seabed mixer 16 and continuously stirred. The carbon dioxide hydrate-mud mixed slurry is made by the driving force of the seabed high pressure and the low temperature of seawater. The carbon dioxide hydrate-mud mixed slurry is transported to the seabed depression location 13 through the mixed slurry output system 10; and then an artificial carbon dioxide reservoir is formed by covering the mud layer to realize the safe storage of carbon dioxide on the seabed.

[0049] Reference Figure 2 -and Figure 3The hydrate subsea mixing integrated core system 8 mentioned in the present invention is composed of a carbon dioxide hydrate generation subsea mixer 16, a surfactant injection submodule 17, a mud slurry injection submodule 18, a seawater injection submodule 19, and a mixed slurry output submodule 20, which are installed in combination on the upper side of a core support and mobile submodule 21. When the core support and mobile submodule 21 moves the position, one side of the carbon dioxide hydrate generation subsea mixer 16 is connected to the mud slurry injection submodule 18 through a mud injection port 66 and to the surfactant injection submodule 17 through a surfactant injection port 67. The other side of the carbon dioxide hydrate generation subsea mixer 16 is connected to the seawater injection submodule 19 through a seawater injection port 68. The bottom of the carbon dioxide hydrate generation subsea mixer 16 is connected to the mixed slurry output submodule 20.

[0050] Among them, the above-mentioned carbon dioxide hydrate generation seabed mixer 16 is divided into a mixer stirring functional area 62, a mixer separation functional area 63 and a mixer output functional area 64; the top of the mixer stirring functional area 62 is provided with a carbon dioxide injection port 65, the outer wall of the lower half of the left end is embedded with a mud injection port 66 and a surfactant injection port 67, and the outer wall of the lower half of the right end is embedded with a seawater injection port 68; the inner wall of the mixer stirring functional area 62 is provided with a mixing stirring device 70, and the mixing stirring device 70 is composed of a stirring rotating motor 71, a vertical rotating rod 72 and a horizontal rotating rod 73, and each horizontal rotating rod 73 is equipped with multiple Trapezoidal stirring blades 74; a plurality of mixer temperature and pressure sensors 69 are distributed on the inner wall of the carbon dioxide hydrate generating seabed mixer 16, and a mixer bracket 76 is provided on the lower outer side to leave enough space at the bottom to realize the connection between the mixed slurry output horizontal straight pipe 96 and the bottom of the right inner wall of the mixer output functional area 64; the core bearing and moving submodule 21 includes a core system crawler wheel 22, a core system bearing base 23 and a drag hook 24. The bottom of the core system bearing base 23 is provided with multiple sets of core system crawler wheels 22, and drag hooks 24 are respectively provided at both ends of the core system bearing base 23.

[0051] The above-mentioned surfactant injection submodule 17 is composed of a surfactant stirring tank 77, a surfactant delivery straight pipe 78, and a surfactant delivery pump 79. The top of the surfactant stirring tank 77 is provided with a surfactant riser injection port 80, which is connected to the surfactant injection riser 7; the inner wall of the surfactant stirring tank 77 is equipped with a surfactant stirring device 81, and the inner wall of the surfactant stirring tank 77 is provided with a tank temperature and pressure sensor 82. The bottom is connected to the carbon dioxide hydrate generation seabed mixer 16 through the surfactant delivery straight pipe 78 and the surfactant delivery pump 79.

[0052] Among them, it should be noted that: the compounding method of the surfactant is: it is compounded by soy lecithin and coconut oil diethanolamide in a ratio of 2:1, and the standard concentration is 300ppm. Soy lecithin and coconut oil diethanolamide both have the properties of foaming, reducing gas-liquid interfacial tension, and forming steric hindrance on the surface of hydrate particles. The latter can also reduce the critical micelle concentration of the former, so that more soybean lecithin molecules act on the gas-liquid interface. After the two are compounded, they can effectively promote the formation of carbon dioxide hydrates. At the same time, they can also effectively prevent the aggregation formed by carbon dioxide hydrates and sediment from depositing and clogging in the carbon dioxide hydrate generation seabed mixer 16 and the mixed slurry output system 10, providing conditions for the rapid generation of carbon dioxide hydrates and the stable and continuous discharge of mixed slurry. On the other hand, the two substances in the surfactant are natural active substances, which can be naturally decomposed after being discharged to the seabed with the mixed slurry, and are friendly to the marine environment. For specific reference Figure 6 It can be seen that after the addition of surfactant, the concentration of carbon dioxide hydrate increased significantly, indicating that the surfactant promoted the formation of carbon dioxide hydrate; in addition, the loop flow experiment time was significantly prolonged, which shows that the surfactant prevented the deposition of carbon dioxide hydrate-sediment mixed solid aggregates 11.

[0053] The above-mentioned mud slurry injection submodule 18 is composed of a mud conveying telescopic hose 36, a mud conveying hose retractor 83, a mud conveying vertical straight pipe 84, a secondary mud conveying pump bracket 85, a secondary mud conveying pump 86, and a mud conveying horizontal straight pipe 87. The output end of the secondary mud conveying pump 86 is connected to the carbon dioxide hydrate generation seabed mixer 16 through the mud conveying horizontal straight pipe 87; the secondary mud conveying pump bracket 85, the mud conveying vertical straight pipe 84 and the mud conveying hose retractor 83 are installed on the lower side of the secondary mud conveying pump 86, and the distance and relative position between the mud seabed collection system 9 and the hydrate seabed mixing integrated core system 8 are controlled by the mud conveying telescopic hose 36 and the mud conveying hose retractor 83.

[0054] The above-mentioned seawater injection submodule 19 consists of a seawater suction inlet 88, a seawater suction vertical pipe ball valve 89, a solid filter device 90, a filter device bracket 91, a seawater suction horizontal straight pipe 92, a seawater suction pump 93, a seawater suction pump bracket 94, a liquid recovery telescopic hose 59, and a liquid recovery telescopic hose tail end ball valve 95. The output end of the seawater suction pump 93 is connected to the carbon dioxide hydrate generating seabed mixer 16, and the input end of the seawater suction pump 93 is connected to the seawater suction inlet 88 through the seawater suction horizontal straight pipe 92 and the solid filter device 90. The filter device bracket 91 is installed on the lower side of the solid filter device 90, and the seawater suction pump bracket 94 is installed on the lower side of the seawater suction pump 93.

[0055] The solid filtering device 90 is mainly used to filter solids and fish pumped in together with seawater. The left end of the seawater pumping pump 93 is connected to the seawater injection port 68 on the carbon dioxide hydrate generation seabed mixer 16 through the seawater pumping horizontal straight pipe 92. When the seawater injection step is performed alone, the ball valve 95 at the tail end of the liquid recovery telescopic hose is closed, and the seawater pumping vertical pipe ball valve 89 is opened to prevent seawater from directly flowing into the mixed slurry output system 10; when the liquid recovery step in the mixed slurry output system 10 is performed alone, the seawater pumping vertical pipe ball valve 89 is closed, and the ball valve 95 at the tail end of the liquid recovery telescopic hose is opened to prevent the recovered liquid from flowing out of the seawater pumping port 88. The liquid 12 that does not participate in hydrate formation is recovered from the mixed slurry output system 10 through the seawater injection submodule 19 and pumped into the carbon dioxide hydrate generation seabed mixer 16.

[0056] The above-mentioned mixed slurry output submodule 20 is composed of a mixed slurry output horizontal straight pipe 96, a mixed slurry output pipe ball valve 97, a first-level mixed slurry output pump 98, a mixed slurry output hose telescopic device 99, and a mixed slurry output telescopic hose 42. The input end of the first-level mixed slurry output pump 98 is connected to the carbon dioxide hydrate generation seabed mixer 16 through the mixed slurry output horizontal straight pipe 96, and the output end of the first-level mixed slurry output pump 98 is connected to the mixed slurry output system 10 through the mixed slurry output hose telescopic device 99 and the mixed slurry output telescopic hose 42.

[0057] During the injection of carbon dioxide, surfactant, mud, and seawater, and the hydrate formation and mixed slurry mixing processes within the CO2 hydrate generation subsea mixer 16, the mixed slurry output pipe ball valve 97 is closed. It is opened when the mixed slurry is being output, and the mixed slurry within the CO2 hydrate generation subsea mixer 16 is discharged to the subsea depression 13 through the mixed slurry output submodule 20 and the mixed slurry output system 10. The mixed slurry output hose retractable device 99 and the mixed slurry output retractable hose 42 enable free control of the distance and relative position between the mixed slurry output system 10 and the integrated subsea hydrate mixing core system 8, facilitating the movement of equipment after replacement within the subsea depression 13 and controlling the deposition location and accumulation morphology of the CO2 hydrate-sediment mixed solid aggregate 11 and other solids such as sediment during the formation of the artificial CO2 hydrate reservoir.

[0058] Reference Figure 4The mud seabed collection system 9 mentioned in the present invention is composed of a sediment impactor 25, a mud collector 26, a mud pumping pipe 27, a mud pumping pump and a solid filter device 28, a mud pumping port 29, a mud stirring storage tank 30, a mud stirring device 31, a mud storage tank temperature and pressure sensor 32, a small seawater pumping pump and a solid filter device 33, a mud delivery straight pipe 34, a first-level mud delivery pump 35, a mud delivery retractable hose 36, a collection system crawler wheel 37, a collection system supporting base 38, a collection system mobile controller 39, and a small seawater extraction port 40. The collection system crawler wheel 37 is provided at the bottom of the collection system supporting base 38, and a mud stirring storage tank is installed on the upper side of the collection system supporting base 38. 30. The top of the mud stirring storage tank 30 is connected to the small seawater suction port 40 through a small seawater suction pump and a solid filtering device 33. A mud suction pump and a solid filtering device 28 and a collection system mobile controller 39 are provided on the left side of the mud stirring storage tank 30. The outer side of the mud suction pump and the solid filtering device 28 is connected to the mud collector 26 through a mud suction pipe 27. A mud impactor 25 is installed on the lower side of the mud collector 26; on the right side of the mud stirring storage tank 30, a first-level mud delivery pump 35 is connected through a mud delivery straight pipe 34, and the outer end of the first-level mud delivery pump 35 is connected to the mud and sand slurry injection submodule 18 through a mud delivery telescopic hose 36; a mud stirring device 31 is installed in the inner cavity of the mud stirring storage tank 30.

[0059] The mud impactor 25 disperses and lifts the mud on the surface of the seabed formation, initially forming mud with seawater. The mud then passes through the mud collector 26, the mud inlet pipe 27, the mud inlet pump and solid filter 28, and the mud inlet port 29 before being pumped into the mud mixing tank 30. The mud mixing device 31 rotates and continuously stirs the mud to prevent the mud from settling in a static state. Simultaneously, seawater at the top of the mud mixing tank 30 passes through the small seawater inlet 40, the small seawater inlet pump and solid filter 33, and the mud tank seawater inlet port 41 before being pumped into the mud mixing tank 30 and mixed with the existing mud. This reduces the concentration of mud in the tank, thereby preventing excessively high mud concentrations from negatively impacting the conveying device and the formation of carbon dioxide hydrates. The mud mixing storage tank 30 is cylindrical in shape, and two mud storage tank temperature and pressure sensors 32 are provided on the symmetrical side walls at the axial middle position. When the temperature and pressure in the tank reach the set standards, the mud slurry in the tank, which has been in a stirring state, is transported to the hydrate seabed mixing integrated core system 8 through the mud delivery straight pipe 34, the first-level mud delivery pump 35, and the mud delivery retractable hose 36 in sequence.

[0060] Reference Figure 5The mixed slurry output system 10 mentioned in the present invention includes a mixed slurry output telescopic hose 42, a secondary mixed slurry output pump 43, an extendable hose 44 in front of the mixed slurry discharge pipe, a mixed slurry discharge pipe lifter 45, a mixed slurry discharge pipe 46, a mixed slurry discharge guide plate 47, an output system track wheel 48, an output system supporting base 49 and an output system mobile controller 50. The output system track wheel 48 is installed on the lower side of the output system supporting base 49, and the secondary mixed slurry output pump 43 and the output system mobile controller 50 are installed on the upper side. The left end of the secondary mixed slurry output pump 43 is connected to the mixed slurry output telescopic hose 42, and the right end is connected to the mixed slurry discharge pipe 46 through the extendable hose 44 in front of the mixed slurry discharge pipe. A mixed slurry discharge guide plate 47 is provided on the lower side of the mixed slurry discharge pipe 46. The carbon dioxide hydrate-sediment mixed slurry is transported to the seabed depression location 13 through the mixed slurry discharge pipe 46 and the mixed slurry discharge guide plate 47.

[0061] The extendable hose 44 and the mixed slurry discharge pipe lift 45 in front of the mixed slurry discharge pipe allow for adjustment of the vertical height of the mixed slurry discharge point. The mixed slurry discharge guide plate 47 is telescopic and can be adjusted at any angle relative to the outlet at the end of the mixed slurry discharge pipe 46, allowing for adjustment of the horizontal position of the mixed slurry discharge point. The combination of these three elements allows for control of the deposition location and accumulation morphology of carbon dioxide hydrate solid aggregates, sediment, and carbon dioxide hydrate-sediment mixed solid aggregates 11 in the mixed slurry.

[0062] The method for using the equipment for solidifying and storing carbon dioxide in artificial submarine hydrate reservoirs mentioned in the present invention is technically divided into four stages: continuous injection stage, hydrate generation and slurry mixing stage, mixed slurry discharge stage, and sediment layer covering stage;

[0063] First, in the continuous injection stage, the liquid carbon dioxide and surfactant on the transport ship 1, the mud slurry formed in the seabed stratum 14, and the low-temperature seawater near the seabed need to be injected into the carbon dioxide hydrate generation seabed mixer 16 in sequence. The main steps include:

[0064] a1. Preparation before system deployment: Before deploying all equipment to the seabed formation 14, the pressure in the carbon dioxide hydrate generation seabed mixer 16, the mud mixing tank 30, and the surfactant mixing tank 77 is set to 0 MPa and kept completely sealed;

[0065] a2. System deployment on the seabed: The transport vessel 1 floats on the sea level 15. The hydrate seabed slurry mixing integrated core system 8, the mud seabed collection system 9, and the mixed slurry output system 10 are lowered to the seabed stratum 14 at a water depth of 800 to 2000 meters according to the location of different seabed depressions 13. The seabed anchoring device 100 installed on the core system crawler wheel 22 is inserted into the seabed stratum 14. The carbon dioxide injection pump 4 and the surfactant injection pump 6 on the transport vessel 1 are respectively injected through the carbon dioxide riser 5 and the surfactant injection riser 6. Pipe 7 is connected to the carbon dioxide injection port 65 and the surfactant riser injection port 80; the collection system movement controller 39 is used to move the mud seabed collection system 9 to a position near the hydrate seabed slurry mixing integrated core system 8, and the seabed anchoring device 100 installed on the collection system crawler 37 is inserted into the seabed formation 14; the output system movement controller 50 is used to move the mixed slurry output system 10 to a position near the seabed depression 13, and the seabed anchoring device 100 installed on the output system crawler 48 is inserted into the seabed formation 14;

[0066] a3. Surfactant injection and cooling: Open the ball valve in the surfactant riser injection port 80 to inject surfactant into the surfactant stirring tank 77. Simultaneously, start the surfactant stirring device 81. When the pressure in the surfactant stirring tank 77 approaches the pressure at the seabed, stop the injection and close the ball valve in the surfactant riser injection port 80. Continue stirring to accelerate the heat exchange process between the surfactant and the low-temperature seawater through the outer wall of the surfactant stirring tank 77.

[0067] a4. Collection and dilution of seabed mud slurry: While the surfactant injection and cooling steps are in progress, the mud impactor 25 in the mud seabed collection system 9 is used to disperse and lift the mud in the seabed formation 14 to initially form mud with seawater. Simultaneously, the ball valve in the mud pumping port 29, the mud pumping pump and solid filter device 28, the small seawater pumping pump and solid filter device 33, and the mud stirring device 31 are opened to pump the initially formed mud and seawater on the seabed into the mud stirring tank 30 and continuously stir them. The pressure is monitored by the mud tank temperature and pressure sensor 32. When the pressure in the mud stirring tank 30 reaches the pressure value at the seabed, all pumps and ball valves in the mud seabed collection system 9 are closed.

[0068] a5. Injecting carbon dioxide: When the temperature of the surfactant in the surfactant stirring tank 77 drops below the carbon dioxide hydrate phase equilibrium temperature corresponding to the seabed pressure, the ball valve in the carbon dioxide injection port 65 is opened to inject liquid carbon dioxide into the carbon dioxide hydrate generating seabed mixer 16. Simultaneously, the mixing and stirring device 70 is opened. When the internal pressure reaches 0.8 times the seabed pressure, the injection is stopped and the ball valve in the carbon dioxide injection port 65 is closed.

[0069] a6. Injecting low-temperature surfactant: Start the surfactant delivery pump 79, open the ball valve in the surfactant injection port 67, and inject the surfactant into the CO2 hydrate generation subsea slurry mixer 16, while keeping the surfactant stirring device 81 and the slurry stirring device 70 open. When the injection volume reaches the design standard, stop the injection, close the ball valve in the surfactant injection port 67 and the surfactant delivery pump 79;

[0070] a7. Injecting mud slurry: Start the primary mud delivery pump 35 and the secondary mud delivery pump 86, open the ball valve in the mud injection port 66, and deliver the mud slurry with a reduced mud concentration after being diluted with seawater to the CO2 hydrate generation seabed mixer 16. At the same time, keep the mud stirring device 31 and the slurry stirring device 70 open to prevent mud deposition. When the injection volume reaches the design standard, stop the injection and close the ball valve in the mud injection port 66, the primary mud delivery pump 35, and the secondary mud delivery pump 86.

[0071] a8. Injecting low-temperature seawater: Confirm that the ball valve 95 at the tail end of the liquid recovery retractable hose is closed, open the ball valve 89 of the seawater inlet vertical pipe, start the seawater inlet pump 93, open the ball valve in the seawater injection port 68, and inject low-temperature seawater near the seabed that has been filtered through solids into the carbon dioxide hydrate generating seabed mixer 16. Simultaneously, start the mixing and stirring device 70. When the injection volume reaches the design standard, stop the injection, close the ball valve in the seawater injection port 68, the seawater inlet pump 93, and the ball valve 89 of the seawater inlet vertical pipe;

[0072] Second, in the hydrate formation and slurry mixing stage, the main steps are as follows:

[0073] b1. Hydrate formation: The rotational speed of the mixing and stirring device 70 in the CO2 hydrate generation seabed mixer 16 is increased, so that the CO2 in the high-seawater-content mud slurry stirring system reacts with the seawater under the action of the high seawater pressure, low seawater temperature driving force, and surfactants to rapidly generate CO2 hydrate. The temperature and pressure of different areas in the CO2 hydrate generation seabed mixer 16 are monitored by multiple mixer temperature and pressure sensors 69, and an internally installed pressure-resistant high-definition camera lens 75 assists in observation. When a significant sudden temperature increase occurs, indicating the onset of CO2 hydrate formation, the hydrate formation amount is calculated based on the real-time changes in temperature and pressure.

[0074] b2. Formation of a CO2 hydrate-sediment mixed slurry by hydrates and sediment: When the temperature and pressure in various regions of the CO2 hydrate-generating seabed mixer 16 no longer change significantly, the rotation rate of the mixing and stirring device 70 is reduced. Under the influence of the surfactant, the hydrate particles and small hydrate aggregates are stirred with the sediment and seawater to gradually form a CO2 hydrate-sediment mixed slurry with good fluidity. By monitoring the feedback torque power of the mixing and stirring device 70, when the torque power no longer fluctuates significantly, it indicates that the properties and stirring state of the CO2 hydrate-sediment mixed slurry formed by the CO2 hydrate and sediment have stabilized.

[0075] Third, in the mixed slurry discharge stage, the main steps are as follows:

[0076] c1. Discharge of the mixed slurry: Maintain the uniform rotation of the slurry mixing device 70 to prevent the deposition of the carbon dioxide hydrate-sediment mixed slurry; adjust the mixed slurry discharge pipe lift 45 to the lowest position, open the mixed slurry output pipe ball valve 97, start the first mixed slurry output pump 98 and the second mixed slurry output pump 43, and discharge the carbon dioxide hydrate-sediment mixed slurry to the lowest level of the seabed depression 13. While discharging, adjust the mixed slurry discharge guide plate 47 to ensure that the solid aggregates in the carbon dioxide hydrate-sediment mixed slurry are evenly deposited on the lowest level of the seabed depression 13; when the sediment is close to evenly filling the lowest level of the seabed depression 13, raise the mixed slurry discharge pipe lift 45 to start discharging to a higher level of the seabed depression 13, and repeat the cycle until the seabed depression 13 is nearly filled;

[0077] Fourth, in the sediment layer covering stage, the main steps are as follows:

[0078] d1. Injection of sediment slurry: Repeat the steps of collecting and diluting the seabed sediment slurry, injecting the low-temperature surfactant, injecting the sediment slurry, and injecting the seawater in the continuous injection phase to make the pressure in the carbon dioxide hydrate generation seabed slurry mixer 16 close to the pressure before the mixed slurry is discharged, while maintaining the uniform rotation speed of the slurry mixing device 70;

[0079] d2. Discharge of silt slurry: Pull out the seabed anchoring device 100 on the track wheel 48 of the output system, and discharge the silt slurry by repeating the mixed slurry discharge step, but do not perform the liquid recovery step. While discharging the silt slurry, adjust the position of the mixed slurry output system 10, the status of the mixed slurry discharge pipe lifter 45 and the mixed slurry discharge guide plate 47 in real time to ensure that the silt is evenly deposited on all the carbon dioxide hydrate-silt mixed solid sediments in the seabed depression 13. When the thickness of the formed overlying silt layer reaches the hydrate-silt mixed solid sediment coverage requirement in the depression area, stop all operations, close all pumps and ball valves in the system, and move the entire system to the vicinity of the next seabed depression 13.

[0080] Example 2: Compared with Example 1, the difference between this example is:

[0081] Reference Figure 5 The mixed slurry output system 10 mentioned in this embodiment also includes a liquid recovery wide-mouth device 51, a wide-mouth device tail end baffle 52, a liquid recovery vertical pipe 53, a liquid recovery horizontal pipe 54, a liquid recovery horizontal pipe bracket 55, a solid filtering device 90, a liquid recovery pump 56, a liquid recovery pump bracket 57, a liquid recovery pump lifter 58, a liquid recovery telescopic hose 59, a liquid recovery hose telescopic device 60, and a liquid recovery hose telescopic device bracket 61. The liquid recovery pump 56 is installed on the upper surface of the output system supporting base 49 through the liquid recovery pump bracket 57 and the liquid recovery pump lifter 58, and the solid filtering device 90 is installed on the top of the output system mobile controller 50 through the liquid recovery horizontal pipe bracket 55. One end of the liquid recovery pump 56 is connected to the liquid recovery hose telescopic device 60 through the liquid recovery telescopic hose 59, and the other end is connected to the liquid recovery wide-mouth device 51 through the liquid recovery horizontal pipe 54, the solid filtering device 90 and the liquid recovery vertical pipe 53. The outside of the liquid recovery wide-mouth device 51 is provided with a wide-mouth device tail end baffle 52.

[0082] The wide-mouth liquid recovery device 51 and its tail baffle 52 reduce the loss of liquid 12 not involved in hydrate formation after it is discharged with the mixed slurry. The horizontal liquid recovery pipe support 55, liquid recovery pump support 57, and liquid recovery pump lift 58 enable the synchronous raising and lowering of the wide-mouth liquid recovery device 51, the horizontal liquid recovery pipe 54, and the mixed slurry discharge pipe 46, also to reduce the loss of liquid 12 not involved in hydrate formation after it is discharged. The solids filter 90 is used to filter out solids and fish accidentally drawn in during the liquid recovery process.

[0083] In addition, the third stage: the mixed slurry discharge stage, also includes: recovery of liquid not involved in hydrate formation, discharge of mixed slurry and cessation of liquid recovery, and secondary formation, slurry mixing and discharge of hydrates;

[0084] During the mixed slurry discharge stage, the main steps are as follows:

[0085] c1. Discharge of the mixed slurry: Maintain the uniform rotation of the slurry mixing device 70 to prevent the deposition of the carbon dioxide hydrate-sediment mixed slurry; synchronously adjust the mixed slurry discharge pipe lift 45 and the liquid recovery pump lift 58 to the lowest position, open the mixed slurry output pipe ball valve 97, start the first mixed slurry output pump 98 and the second mixed slurry output pump 43, and discharge the carbon dioxide hydrate-sediment mixed slurry to the lowest level of the seabed depression 13. While discharging, adjust the mixed slurry discharge guide plate 47 to ensure that the solid aggregates in the carbon dioxide hydrate-sediment mixed slurry are evenly deposited on the lowest level of the seabed depression 13; when the sediment is close to evenly filling the lowest level of the seabed depression 13, synchronously raise the mixed slurry discharge pipe lift 45 and the liquid recovery pump lift 58 so that they begin to discharge to a higher level of the seabed depression 13, and repeat the cycle until the seabed depression 13 is nearly filled;

[0086] c2. Recovery of liquid not involved in hydrate formation: While the CO2 hydrate-sediment mixed slurry is being discharged through the mixed slurry discharge pipe 46, ensure that the ball valve 89 of the seawater pumping vertical pipe is closed. Open the ball valve 95 at the tail end of the liquid recovery telescopic hose and the ball valve in the seawater injection port 68. Start the liquid recovery pump 56 and the seawater pumping pump 93 at a power level equal to 0.5 times the total power of the primary mixed slurry output pump 98 and the secondary mixed slurry output pump 43. Liquid CO2 not involved in hydrate formation and seawater saturated with CO2 discharged from the mixed slurry discharge pipe 46 are sequentially passed through the liquid recovery wide-mouth device 51, the liquid recovery vertical pipe 53, the liquid recovery horizontal pipe 54, the solids filter device 90, the liquid recovery pump 56, the liquid recovery telescopic hose 59, the solids filter device 90 in the seawater injection submodule 19, the seawater pumping horizontal straight pipe 92, the seawater pumping pump 93, and the seawater injection port 68, and are then recovered into the CO2 hydrate generation subsea slurry mixer 16.

[0087] c3. Stopping the discharge of the mixed slurry and the recovery of liquid: During the cycle of discharging the CO2 hydrate-sediment mixed slurry at 1 times the power and recovering the liquid at 0.5 times the power, the agitation state of the mixed slurry in the CO2 hydrate generation seabed mixer 16 is monitored in real time by means of the pressure-resistant high-definition camera lens 75, the mixer temperature and pressure sensor 69, and the feedback torque power of the mixing and stirring device 70. When the transmittance of the mixed slurry through the pressure-resistant high-definition camera lens 75 approaches that of seawater, it indicates that the content of hydrate-sediment mixed aggregates in the CO2 hydrate-sediment mixed slurry is close to zero. When the temperature of a certain area in the CO2 hydrate generation seabed mixer 16 suddenly rises significantly or the feedback torque power of the mixing and stirring device 70 suddenly increases, it indicates that secondary formation of CO2 hydrate has occurred. If any of the above three situations occurs, the discharge of the mixed slurry and the recovery of the liquid 12 not involved in hydrate formation are stopped, and all pumps and ball valves in the mixed slurry output submodule 20, the mixed slurry output system 10, and the seawater injection submodule 19 are closed.

[0088] c4. Secondary hydrate formation, slurry mixing, and discharge: Repeat the steps of carbon dioxide injection, surfactant injection, and mud slurry injection in the continuous injection stage. Stop the injection when the pressure in the seabed mixer 16 for carbon dioxide hydrate formation approaches the pressure before the mixed slurry is discharged. Repeat all the steps of the hydrate formation and slurry mixing stage. When secondary hydrate formation is detected and the properties and agitation state of the mixed slurry are stable, repeat all the steps of the mixed slurry discharge stage. Repeat the four steps described in the mixed slurry discharge stage until the seabed depression 13 is nearly completely filled with carbon dioxide hydrate-mud mixed solid sediments, at which point the mixed slurry discharge and liquid recovery are stopped.

[0089] The above descriptions are merely some preferred embodiments of the present invention. Anyone skilled in the art may be able to modify the above-described technical solutions or convert them into equivalent technical solutions. Therefore, any corresponding simple modifications or equivalent transformations based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An apparatus for solidifying and storing carbon dioxide in an artificial submarine hydrate reservoir, comprising a transport vessel (1) and a liquid carbon dioxide storage tank (2), characterized in that: The transport vessel (1) further comprises a surfactant storage tank (3), a carbon dioxide injection pump (4), a carbon dioxide injection riser (5), a surfactant injection pump (6), a surfactant injection riser (7), a hydrate seabed slurry integrated core system (8), a mud seabed collection system (9) and a mixed slurry output system (10). The bottom of the transport vessel (1) is connected to the hydrate seabed slurry integrated core system (8) on the seabed formation (14) through the carbon dioxide injection riser (5) and the surfactant injection riser (7). The mud seabed collection system (9) is provided on one side of the hydrate seabed slurry integrated core system (8), and the mixed slurry output system (10) is provided on the other side. The carbon dioxide injection riser (5) and the surfactant injection riser (7) inject the carbon dioxide and surfactant from the transport ship (1) into the hydrate seabed slurry integrated core system (8), and form a mud slurry through the mud seabed collection system (9). The surfactant, mud slurry and seawater are pumped into the carbon dioxide hydrate generating seabed mixer (16) and continuously stirred. The carbon dioxide hydrate-mud mixed slurry is formed by the driving force of the seabed high pressure and the low temperature of seawater. The carbon dioxide hydrate-mud mixed slurry is transported to the seabed depression (13) through the mixed slurry output system (10); and then an artificial carbon dioxide reservoir is formed by covering the mud layer to achieve safe seabed storage of carbon dioxide. The hydrate seabed slurry integration core system (8) is composed of a carbon dioxide hydrate generating seabed mixer (16), a surfactant injection submodule (17), a mud slurry injection submodule (18), a seawater injection submodule (19), and a mixed slurry output submodule (20), which are assembled and installed on the upper side of the core bearing and moving submodule (21). The position is moved by the core bearing and moving submodule (21). One side of the carbon dioxide hydrate generating seabed mixer (16) is connected to the mud slurry injection submodule (18) through the mud injection port (66), and is connected to the surfactant injection submodule (17) through the surfactant injection port (67). The other side of the carbon dioxide hydrate generating seabed mixer (16) is connected to the seawater injection submodule (19) through the seawater injection port (68), and the bottom of the carbon dioxide hydrate generating seabed mixer (16) is connected to the mixed slurry output submodule (20); The carbon dioxide hydrate generation seabed mixer (16) is divided into a mixer stirring functional area (62), a mixer separation functional area (63) and a mixer output functional area (64); the top of the mixer stirring functional area (62) is provided with a carbon dioxide injection port (65), the outer wall of the lower half of the left end is embedded with a mud injection port (66) and a surfactant injection port (67), and the outer wall of the lower half of the right end is embedded with a seawater injection port (68); the inner wall of the mixer stirring functional area (62) is provided with a mixing stirring device (70), and the mixing stirring device (70) is composed of a stirring rotating motor (71), a vertical rotating rod (72) and a horizontal rotating rod (73), and each horizontal rotating rod (73) is equipped with A plurality of trapezoidal stirring blades (74); a plurality of mixer temperature and pressure sensors (69) are distributed on the inner wall of the carbon dioxide hydrate generating seabed mixer (16); a mixer bracket (76) is provided on the lower outer portion for leaving enough space at the bottom to realize the connection between the mixed slurry output horizontal straight pipe (96) and the bottom of the right inner wall of the mixer output functional area (64); the core bearing and moving submodule (21) includes a core system crawler wheel (22), a core system bearing base (23) and a drag hook (24); a plurality of core system crawler wheels (22) are provided at the bottom of the core system bearing base (23), and a drag hook (24) is provided at each end of the core system bearing base (23).

2. The equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 1, characterized in that: The surfactant injection submodule (17) is composed of a surfactant stirring storage tank (77), a surfactant delivery straight pipe (78), and a surfactant delivery pump (79). The top of the surfactant stirring storage tank (77) is provided with a surfactant riser injection port (80) which is connected to the surfactant injection riser (7); the inner wall of the surfactant stirring storage tank (77) is provided with a surfactant stirring device (81), and the inner wall of the surfactant stirring storage tank (77) is provided with a storage tank temperature and pressure sensor (82). The bottom is connected to the carbon dioxide hydrate generation seabed mixer (16) through the surfactant delivery straight pipe (78) and the surfactant delivery pump (79).

3. The equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 2, characterized in that: The mud slurry injection submodule (18) is composed of a mud conveying telescopic hose (36), a mud conveying hose telescope (83), a mud conveying vertical straight pipe (84), a secondary mud conveying pump bracket (85), a secondary mud conveying pump (86), and a mud conveying horizontal straight pipe (87). The output end of the secondary mud conveying pump (86) is connected to the carbon dioxide hydrate generation seabed mixer (16) through the mud conveying horizontal straight pipe (87); the secondary mud conveying pump bracket (85), the mud conveying vertical straight pipe (84) and the mud conveying hose telescope (83) are installed on the lower side of the secondary mud conveying pump (86), and the distance and relative position between the mud seabed acquisition system (9) and the hydrate seabed mixing integrated core system (8) are controlled by the mud conveying telescopic hose (36) and the mud conveying hose telescope (83).

4. The equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 3, characterized in that: The seawater injection submodule (19) is composed of a seawater pumping inlet (88), a solid filtering device (90), a filtering device bracket (91), a seawater pumping horizontal straight pipe (92), a seawater pumping pump (93), and a seawater pumping pump bracket (94). The output end of the seawater pumping pump (93) is connected to the carbon dioxide hydrate generating seabed slurry mixer (16), and the input end of the seawater pumping pump (93) is connected to the seawater pumping inlet (88) through the seawater pumping horizontal straight pipe (92) and the solid filtering device (90). The filtering device bracket (91) is installed on the lower side of the solid filtering device (90), and the seawater pumping pump bracket (94) is installed on the lower side of the seawater pumping pump (93).

5. The equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 4, characterized in that: The mixed slurry output submodule (20) is composed of a mixed slurry output horizontal straight pipe (96), a first-stage mixed slurry output pump (98), a mixed slurry output hose telescopic device (99), and a mixed slurry output telescopic hose (42). The input end of the first-stage mixed slurry output pump (98) is connected to the carbon dioxide hydrate generation seabed mixer (16) through the mixed slurry output horizontal straight pipe (96), and the output end of the first-stage mixed slurry output pump (98) is connected to the mixed slurry output system (10) through the mixed slurry output hose telescopic device (99) and the mixed slurry output telescopic hose (42).

6. The equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 5, characterized in that: The mud seabed collection system (9) is composed of a sediment impactor (25), a mud collector (26), a mud pumping pipe (27), a mud pumping pump solid filter device (28), a mud pumping port (29), a mud stirring storage tank (30), a mud stirring device (31), a mud storage tank temperature and pressure sensor (32), a small seawater pumping pump solid filter device (33), a mud delivery straight pipe (34), a first-stage mud delivery pump (35), a mud delivery retractable hose (36), a collection system crawler wheel (37), a collection system supporting base (38), a collection system mobile controller (39), and a small seawater pumping port (40). The bottom of the collection system supporting base (38) is provided with a collection system crawler wheel (37), and the upper side of the collection system supporting base (38) is provided with a mud stirring storage tank (33). 0), the top of the mud stirring storage tank (30) is connected to the small seawater suction port (40) through the small seawater suction pump solid filter device (33), the mud suction pump solid filter device (28) and the collection system mobile controller (39) are provided on the left side of the mud stirring storage tank (30), the outer side of the mud suction pump solid filter device (28) is connected to the mud collector (26) through the mud suction pipe (27), and the mud impactor (25) is installed on the lower side of the mud collector (26); the right side of the mud stirring storage tank (30) is connected to the first-level mud delivery pump (35) through the mud delivery straight pipe (34), and the outer end of the first-level mud delivery pump (35) is connected to the mud slurry injection submodule (18) through the mud delivery telescopic hose (36); the mud stirring device (31) is installed in the inner cavity of the mud stirring storage tank (30).

7. The equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 6, characterized in that: The mixed slurry output system (10) comprises a mixed slurry output telescopic hose (42), a secondary mixed slurry output pump (43), an extendable hose (44) in front of the mixed slurry discharge pipe, a mixed slurry discharge pipe lifter (45), a mixed slurry discharge pipe (46), a mixed slurry discharge guide plate (47), an output system crawler wheel (48), an output system supporting base (49) and an output system movement controller (50), wherein the output system crawler wheel (48) is installed on the lower side of the output system supporting base (49), and the secondary mixed slurry output pump (43) is installed on the upper side. A mixed slurry output pump (43) and an output system mobile controller (50) are provided. The left end of the secondary mixed slurry output pump (43) is connected to a mixed slurry output telescopic hose (42), and the right end is connected to a mixed slurry discharge pipe (46) through an extendable hose (44) in front of the mixed slurry discharge pipe. A mixed slurry discharge guide plate (47) is provided on the lower side of the mixed slurry discharge pipe (46). The carbon dioxide hydrate-sediment mixed slurry is transported to a seabed depression (13) through the mixed slurry discharge pipe (46) and the mixed slurry discharge guide plate (47).

8. The method for using the equipment for solidifying and storing carbon dioxide in a submarine artificial hydrate reservoir according to claim 7, wherein: It is mainly divided into four stages: continuous injection stage, hydrate generation and slurry mixing stage, mixed slurry discharge stage, and mud layer covering stage; First, in the continuous injection stage, the liquid carbon dioxide and surfactant on the transport ship (1), the mud slurry formed by the seabed formation (14), and the low-temperature seawater near the seabed need to be injected into the carbon dioxide hydrate generation seabed mixer (16) in sequence, which mainly includes the following steps: a1. Preparation before arranging the system: Before arranging all equipment in the seabed formation (14), the pressure in the carbon dioxide hydrate generating seabed mixer (16), the mud mixing tank (30), and the surfactant mixing tank (77) is set to 0 MPa and kept in a completely sealed state; a2. Arrangement of the system to the seabed: according to the location of different seabed depressions (13), the hydrate seabed slurry integrated core system (8), the mud seabed collection system (9), and the mixed slurry output system (10) are lowered to the seabed formation (14) at a water depth of 800 to 2000 meters; the seabed anchoring device (100) installed on the core system crawler wheel (22) is inserted into the seabed formation (14), and the carbon dioxide injection pump (4) and the surfactant injection pump (6) on the transport ship (1) are respectively connected to the carbon dioxide injection riser (5) and the surfactant injection riser (7) through the carbon dioxide injection riser (5). The inlet port (65) is connected to the surfactant riser injection port (80); the mud seabed collection system (9) is moved to a position near the hydrate seabed slurry integration core system (8) through the collection system movement controller (39), and the seabed anchoring device (100) installed on the collection system crawler (37) is inserted into the seabed formation (14); the mixed slurry output system (10) is moved to a position near the seabed depression (13) through the output system movement controller (50), and the seabed anchoring device (100) installed on the output system crawler (48) is inserted into the seabed formation (14); a3. Surfactant injection and cooling: Open the ball valve in the surfactant riser injection port (80), inject the surfactant into the surfactant stirring tank (77), and simultaneously start the surfactant stirring device (81). When the pressure in the surfactant stirring tank (77) equals the pressure at the seabed, stop the injection and close the ball valve in the surfactant riser injection port (80). Continue stirring to accelerate the heat exchange process between the surfactant and the low-temperature seawater through the outer wall of the surfactant stirring tank (77); a4. Collection and dilution of seabed mud slurry: While the surfactant injection and cooling steps are being carried out, the mud impactor (25) in the mud seabed collection system (9) is used to disperse and lift the mud in the seabed formation (14) to initially form mud with seawater. At the same time, the ball valve in the mud pumping port (29), the mud pumping pump solid filter device (28), the small seawater pumping pump solid filter device (33) and the mud stirring device (31) are opened to pump the mud and seawater initially formed on the seabed into the mud stirring storage tank (30) and continuously stir. The pressure is monitored by the mud storage tank temperature and pressure sensor (32). When the pressure in the mud stirring storage tank (30) reaches the pressure value at the seabed position, all pumps and ball valves in the mud seabed collection system (9) are closed. a5. Injecting carbon dioxide: When the temperature of the surfactant in the surfactant stirring tank (77) drops below the carbon dioxide hydrate phase equilibrium temperature corresponding to the seabed pressure, the ball valve in the carbon dioxide injection port (65) is opened to inject liquid carbon dioxide into the carbon dioxide hydrate generating seabed mixer (16), and the mixing and stirring device (70) is opened at the same time. When the internal pressure reaches 0.8 times the seabed pressure, the injection is stopped and the ball valve in the carbon dioxide injection port (65) is closed; a6. Injecting low-temperature surfactant: Start the surfactant delivery pump (79), open the ball valve in the surfactant injection port (67), and inject the surfactant into the carbon dioxide hydrate generation seabed slurry mixer (16), while keeping the surfactant stirring device (81) and the slurry stirring device (70) open. When the injection amount reaches the design standard, stop the injection, close the ball valve in the surfactant injection port (67) and the surfactant delivery pump (79); a7. Injecting mud slurry: Start the first-stage mud delivery pump (35) and the second-stage mud delivery pump (86), open the ball valve in the mud injection port (66), and deliver the mud slurry with a reduced mud concentration after being diluted with seawater to the carbon dioxide hydrate generation seabed mixer (16), while keeping the mud stirring device (31) and the slurry stirring device (70) open to avoid sedimentation. When the injection volume reaches the design standard, stop the injection, close the ball valve in the mud injection port (66), the first-stage mud delivery pump (35), and the second-stage mud delivery pump (86); a8. Inject low-temperature seawater: confirm that the ball valve (95) at the tail end of the liquid recovery retractable hose is closed, open the ball valve (89) of the seawater pumping vertical pipe, start the seawater pumping pump (93), open the ball valve in the seawater injection port (68), and inject low-temperature seawater that has been filtered through solids near the seabed into the carbon dioxide hydrate generation seabed mixer (16). At the same time, start the slurry stirring device (70). When the injection volume reaches the design standard, stop the injection, close the ball valve in the seawater injection port (68), the seawater pumping pump (93) and the ball valve (89) of the seawater pumping vertical pipe; Second, in the hydrate formation and slurry mixing stage, the main steps are as follows: b1. Hydrate formation: The rotation speed of the mixing and stirring device (70) in the carbon dioxide hydrate generation seabed mixer (16) is increased, so that the carbon dioxide in the high-seawater-containing mud slurry stirring system rapidly generates carbon dioxide hydrate with seawater under the action of the high seabed pressure, low seawater temperature driving force and surfactant. The temperature and pressure of different areas in the carbon dioxide hydrate generation seabed mixer (16) are monitored by multiple mixer temperature and pressure sensors (69), and the internally installed pressure-resistant high-definition camera lens (75) is used for auxiliary observation. When the temperature suddenly rises significantly, it indicates the start of carbon dioxide hydrate formation. The hydrate formation amount is calculated based on the real-time changes in temperature and pressure. b2. Hydrates and sediments form a carbon dioxide hydrate-sediment mixed slurry: When the temperature and pressure of each region in the seabed mixer (16) where carbon dioxide hydrates are generated no longer change, the rotation rate of the mixing and stirring device (70) is reduced. Under the influence of the surfactant, hydrate particles, small hydrate aggregates, sediment and seawater gradually form a carbon dioxide hydrate-sediment mixed slurry with good fluidity during the stirring process. By monitoring the feedback torque power of the mixing and stirring device (70), when the torque power no longer fluctuates, it is indicated that the properties and stirring state of the carbon dioxide hydrate-sediment mixed slurry formed by carbon dioxide hydrates and sediments have become stable. Third, in the mixed slurry discharge stage, the main steps are as follows: c1. Discharge of mixed slurry: maintain the uniform rotation of the slurry mixing device (70) to avoid the deposition of the carbon dioxide hydrate-sediment mixed slurry; adjust the mixed slurry discharge pipe lifter (45) to the lowest position, open the mixed slurry output pipe ball valve (97), start the first mixed slurry output pump (98) and the second mixed slurry output pump (43), and discharge the carbon dioxide hydrate-sediment mixed slurry to the lowest level of the seabed depression (13); while discharging, adjust the mixed slurry discharge guide plate (47) to ensure that the solid aggregates in the carbon dioxide hydrate-sediment mixed slurry are uniformly deposited on the lowest level of the seabed depression (13); when the sediment evenly fills the lowest level of the seabed depression (13), raise the mixed slurry discharge pipe lifter (45) so that it starts to discharge to a higher level of the seabed depression (13), and circulate in sequence until the seabed depression (13) is filled; Fourth, in the sediment layer covering stage, the main steps are as follows: d1. Injection of sediment slurry: Repeating the steps of collecting and diluting the seabed sediment slurry, injecting the low-temperature surfactant, injecting the sediment slurry, and injecting the seawater in the continuous injection phase, so that the pressure in the carbon dioxide hydrate generating seabed slurry mixer (16) is equal to the pressure before the mixed slurry is discharged, while maintaining the uniform rotation of the slurry mixing device (70); d2. Discharge of sediment slurry: Pull out the seabed anchoring device (100) on the track wheel (48) of the output system, and discharge the sediment slurry by repeating the mixed slurry discharge step, but do not perform the liquid recovery step. While discharging the sediment slurry, adjust the position of the mixed slurry output system (10), the state of the mixed slurry discharge pipe lifter (45) and the mixed slurry discharge guide plate (47) in real time, so that the sediment is evenly deposited on all the carbon dioxide hydrate-sediment mixed solid sediments in the seabed depression (13). When the thickness of the formed overlying sediment layer reaches the coverage requirement of the hydrate-sediment mixed solid sediment in the depression area, stop all operations, close all pumps and ball valves in the system, and move the entire system to the vicinity of the next seabed depression (13).

Images