Mobile injection device and mobile injection method for solidifying carbon dioxide on seabed

Abstract

The invention relates to a mobile spraying device and method for solidifying carbon dioxide on a seabed, the mobile spraying device for solidifying carbon dioxide on the seabed comprises a ship, a CO2 storage tank, a CO2 cooler, a CO2 pump, a depth control system and a CO2 monitoring system are arranged on the ship, the depth control system is provided with a winding drum, one end of a steel wire rope is fixed on the winding drum, and the other end of the steel wire rope is fixed on the ship. The other end of the steel wire rope is fixed on the flexible hose; the depth controller is connected with the sonar depth finder through a cable; the CO2 monitoring room is provided with a monitoring controller, and the monitoring controller is connected with the CO2 detector through a retractable cable; the CO2 injector head comprises an injection shell, an injection cavity, an injection nozzle, a buffer plate, a stirring motor and an inhibitor container, the annular buffer plate is arranged outside the injection shell and located above the injection nozzle, a stirring paddle is arranged in the injection cavity, the inhibitor container is arranged at the top of the injection shell, and a liquid level sensor is arranged at the bottom of the inhibitor container. The CO2 storage cost is low.

Description

Technical Field

[0001] The present invention relates to a technology for depositing solid carbon dioxide (CO2) on the seabed for seabed sealing, and specifically to a mobile injection device and a mobile injection method for solidifying carbon dioxide on the seabed. Background Art

[0002] Industrial activities such as the burning of fossil fuels have increased the emission of CO2 gas. The increase in CO2 gas content caused by this human factor is slowly changing the natural development trend of the earth's climate and has become the main cause of global warming in today's world. Global warming will cause the melting of polar icebergs or ice caps, thereby causing a series of catastrophic problems such as rising sea levels and species extinction.

[0003] Carbon capture technology uses various methods to capture carbon dioxide from factory exhaust gas, and then properly handles or stores it to prevent it from entering the atmosphere. Seabed storage of carbon dioxide is one of the important ways to achieve carbon dioxide emission reduction. The nearshore seabed geological structure is suitable for large-scale storage, and the key emission reduction areas and industries are densely distributed in coastal cities, which is a favorable location for storing CO2. The construction and operation costs of CO2 submarine geological storage are high. The conventional method to reduce costs is to use existing oil and gas exploration data and equipment for site selection and engineering design of carbon dioxide storage. The existing platforms, drilling, pipelines and other equipment can be appropriately modified and used for carbon dioxide transportation and storage, which can significantly reduce the infrastructure cost of offshore storage and shorten the construction period.

[0004] The CCUS process typically involves injecting CO2 into depleted oil and gas reservoirs. . The common advantage of these processes is high efficiency due to high injection capacity into high permeability reservoirs, and the common disadvantage is the risk of CO2 leakage through the wellbore. In recent years, in order to reduce the risk of CO2 leakage, CO2 is usually injected into low-temperature seabed waters in liquid form. Successful CO2 injection cases include the Sleipnir project launched in the Norwegian Sea in 1996, the Hokkaido project launched in 2016, and projects in other regions. Computer simulation studies have shown that the possibility of leakage from geological CO2 storage reservoirs in seabed waters is very low. A common problem with injecting carbon dioxide into seabed waters is the low injection capacity of the injection wells.

[0005] In summary, there is an urgent need for a new device to solidify carbon dioxide on the seabed, which can reduce the impact on the environment as much as possible while reducing the cost of CO2 storage. Summary of the invention

[0006] One object of the present invention is to provide a mobile injection device for solidifying carbon dioxide on the seabed. This mobile injection device for solidifying carbon dioxide on the seabed is used to solve the problems of low injection capacity and high cost of injection wells when injecting carbon dioxide into seabed waters; another object of the present invention is to provide a mobile injection method for this mobile injection device for solidifying carbon dioxide on the seabed.

[0007] The technical solution adopted by the present invention to solve its technical problem is: the mobile injection device for solidifying carbon dioxide on the seabed includes a ship, on which a CO2 storage tank, a CO2 cooler, a CO2 pump, a depth control system, and a CO2 monitoring system are arranged. The CO2 storage tank, the CO2 cooler, and the CO2 pump are connected in sequence, and the CO2 pump is connected to the CO2 injection head through a flexible hose. The depth control system includes a depth control room, in which a drum is arranged, one end of a steel wire rope is fixed on the drum, and the other end of the steel wire rope is fixed on the flexible hose. The drum is connected to a winch motor, and a depth controller in the depth control room is connected to a sonar depth sounder through a cable. The depth of the CO2 injection head lowered into the seawater is controlled by retracting and releasing the steel wire rope, and the position of the CO2 injection head is adjusted in real time to make it close to the seabed; the CO2 monitoring system The system includes a CO2 monitoring room, in which a monitoring controller is arranged, and the monitoring controller is connected to a CO2 detector through a retractable cable. By controlling the retractable cable, the depth of the CO2 detector lowered into the seawater is controlled in real time, so as to monitor the CO2 concentration in the ocean in real time; the CO2 injection head includes an injection shell, an injection chamber, an injection nozzle, a buffer plate, a stirring motor, and an inhibitor container. An annular buffer plate is arranged outside the injection shell, the buffer plate is located above the injection nozzle and covers the injection nozzle underneath, a stirring paddle is arranged in the injection chamber, an inhibitor container is arranged on the top of the injection shell, a liquid level sensor is arranged at the bottom of the inhibitor container, a hydrate inhibitor is contained in the inhibitor container, the inhibitor container is connected to the inhibitor inlet on the top of the injection shell, a second one-way valve and a second flowmeter are installed at the inhibitor inlet, and a temperature and pressure sensor is also installed on the injection shell.

[0008] In the above scheme, the stirring paddle is connected to the variable frequency motor, and the variable frequency motor is arranged on the top of the injection shell.

[0009] In the above solution, a first one-way valve is arranged on the top of the injection shell, the end of the flexible hose is connected to the first one-way valve, and the end of the flexible hose is installed with a first flow meter.

[0010] In the above scheme, the inlet of the CO2 storage tank is connected to the CO2 connecting device, and the CO2 is stored in the CO2 storage tank through the CO2 connecting device.

[0011] The mobile injection method of the mobile injection device for solidifying carbon dioxide on the seabed: When the ship moves in the seawater, the CO2 injection head is placed in the seawater, and then the depth of the CO2 injection head in the seawater is adjusted by the depth control system through the steel wire rope, and the CO2 detector is placed in the seawater at the same time; CO2 is pressurized and encrypted through a CO2 cooler, so that carbon dioxide reaches a supercritical state, so that the ship is loaded with high-density liquid CO2. The cooled CO2 is pumped into a flexible hose by a CO2 pump. CO2 is transmitted to the seabed through the flexible hose, enters the CO2 injection head, and expands and sprays out through the injection nozzle, immediately forming CO2 hydrates on the seabed. CO2 that has not formed hydrates will form hydrates under the buffer plate; when the ship moves, the depth control room receives seawater depth data and adjusts the position of the CO2 injection head in real time to make it close to the seabed. At the same time, the CO2 monitoring room receives seawater CO2 concentration data. When free CO2 is detected, a signal is sent to the CO2 pump controller to control the CO2 injection rate; the formed CO2 hydrates remain on the seabed because their density is higher than that of seawater, realizing the seabed storage of CO2; The variable frequency motor of the CO2 injection head drives the stirring paddle to stir, so that the CO2 injection head is always evenly dispersed in liquid CO2, preventing the CO2 liquid from aggregating in large quantities in the CO2 injection head to form hydrates; The temperature and pressure sensor collects the pressure and temperature of the CO2 injection head, and determines the current rate of liquid CO2 delivery based on the hydrate formation conditions. When hydrates block the CO2 injection head, the injection of hydrate inhibitor is controlled through the second one-way valve and the second flowmeter to prevent and control hydrates or unblock them. The inhibitor container liquid level sensor detects that the hydrate inhibitor is too little and replenishes the inhibitor in time.

[0012] In the above scheme, the free CO2 is covered with a buffer plate, so that the free CO2 that does not immediately form hydrate has more time to be converted into CO2 hydrate. Beneficial Effects

[0013] 1. The present invention has low cost for storing CO2. CO2 is directly deposited to the seabed at a high rate without drilling, eliminating the expensive and troublesome drilling process, the cost of discharging carbon dioxide to the seabed through a hose, and the extremely expensive cost of building a pipeline for transporting carbon dioxide at a location relatively far from the coast. By moving the ship, it can adapt to the carbon dioxide emission location relatively far from the coast, avoiding the high cost of laying pipelines during the carbon dioxide transportation process.

[0014] 2. This process is environmentally friendly. The carbon dioxide flow will not penetrate the seabed, otherwise it may cause geological disasters to the seabed environment in areas where natural gas hydrates are deposited. CO2 hydrates are efficiently generated at commercial rates. CO2 hydrates are generated while ensuring safety and deposited on the seabed without causing environmental problems.

[0015] 3. The present invention uses nozzles to create a local cooling area in the injection head part to reduce the ambient temperature to a temperature far below the temperature at which carbon dioxide hydrates form. In addition, the nozzles will also increase the mixing speed of carbon dioxide, seawater and seabed sand to accelerate the formation of hydrates. CO2 that does not immediately form hydrates rises to the buffer plate to form hydrates.

[0016] 4. The present invention uses the data of the sonar depth sounder to control the depth of the CO2 injection head. The depth control room receives the seawater depth data from the sonar depth sounder and adjusts the position of the injection head according to the data so that the injection head is close to the seabed for CO2 storage.

[0017] 5. The present invention uses the data of CO2 detector to control the CO2 injection rate. When CO2 leaks, ultrasonic tomography is used to locate and characterize the changes caused by the CO2 leakage, so as to realize leakage monitoring in risk areas, and adjust the injection rate by detecting the CO2 content and pH value of seawater.

[0018] 6. The flow meter of the present invention displays the injection flow of liquid CO2, obtains the pressure and temperature of the nozzle through the temperature and pressure sensor, determines the rate at which liquid CO2 needs to be transported according to the hydrate formation conditions, and realizes the rapid formation of hydrates.

[0019] 7. In the present invention, the liquid CO2 is stirred and dispersed by the stirring paddle in the nozzle, and the nozzle sprays and expands, which effectively prevents hydrates from adhering to the nozzle and causing blockage. In addition, the present invention provides a hydrate inhibitor container, and when necessary, controls the injection of the hydrate inhibitor into the nozzle to prevent and control hydrates or unblock them, thereby ensuring the normal operation of the device of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a simplified phase diagram including hydrate-water-gas; Figure 2 It is a schematic diagram of the device of the present invention; Figure 3 It is a schematic diagram of the connection relationship among the CO2 storage tank, the CO2 cooler, the CO2 pump, and the flexible hose in the present invention; Figure 4 is a schematic diagram of a depth control system of the present invention; Figure 5 is a schematic diagram of a CO2 monitoring system of the present invention; Figure 6 Schematic diagram of the CO2 injection head of the present invention.

[0021] In the figure: 1. Ship 2. CO2 connecting device 3. CO2 storage tank 4. CO2 cooler 5. CO2 pump 6. Flexible hose 7. CO2 injection head 8. Injection nozzle 9. Buffer plate 10. Depth control room 11. Sonar depth sounder 12. CO2 monitoring room 13. CO2 detector 14. CO2 hydrate 15-1. First flow meter 15-2. Second flow meter 16-1. First one-way valve 16-2. Second one-way valve 17. Frequency conversion motor 18. Stirring paddle 19. Hydrate inhibitor 20. Temperature and pressure sensor 21 Liquid level sensor. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings: Combination Figure 2-Figure 6 As shown, this mobile injection device for solidifying carbon dioxide on the seabed includes a ship, and a CO2 storage tank, a CO2 cooler, a CO2 pump, a depth control system, and a CO2 monitoring system are arranged on the ship. The inlet of the CO2 storage tank is connected to the CO2 connecting device, and the CO2 is transported and stored in the CO2 storage tank through the CO2 connecting device. The CO2 storage tank, the CO2 cooler, and the CO2 pump are connected in sequence, and the CO2 pump is connected to the CO2 injection head through a flexible hose. The depth control system includes a depth control room, and the depth control room is provided with a drum, one end of the wire rope is fixed on the drum, and the other end of the wire rope is fixed on the flexible hose. The drum is connected to the winch motor. The depth controller in the depth control room is connected to the sonar depth sounder through a cable, and the depth of the CO2 injection head lowered into the seawater is controlled by retracting the wire rope, and the position of the CO2 injection head is adjusted in real time to make it close to the seabed; the CO2 monitoring system includes a CO2 monitoring room, and the CO2 monitoring room is provided with a monitoring controller, and the monitoring controller is connected to the CO2 detector through a retractable cable, and the depth of the CO2 detector lowered into the seawater is controlled in real time by controlling the retractable cable, and the real-time monitoring Ocean CO2 concentration; The CO2 injection head includes an injection shell, an injection chamber, an injection nozzle, a buffer plate, a stirring motor, and an inhibitor container. An annular buffer plate is arranged outside the injection shell, the buffer plate is located above the injection nozzle and covers the injection nozzle below, a stirring paddle is arranged in the injection chamber, the stirring paddle is connected to the frequency conversion motor, the frequency conversion motor is a miniature deep-sea waterproof motor, the frequency conversion motor is arranged at the top of the injection shell, an inhibitor container is arranged on the top of the injection shell, a liquid level sensor is arranged at the bottom of the inhibitor container, a hydrate inhibitor is filled in the inhibitor container, the inhibitor container is connected to the inhibitor inlet on the top of the injection shell, a second one-way valve and a second flowmeter are installed at the inhibitor inlet, and a temperature and pressure sensor is also installed on the injection shell; a first one-way valve is arranged on the top of the injection shell, the end of the flexible hose is connected to the first one-way valve, and the end of the flexible hose is installed with a first flowmeter.

[0023] Figure 1This is a simplified phase diagram of the optimal method of inducing CO2 hydrate formation in the present invention. The equilibrium curve is based on data in the public domain. Under isobaric conditions, the formation of CO2 hydrate by seawater and CO2 is affected by cooling. The point above the equilibrium curve depends on the hydrostatic pressure of the in-situ seawater. Under high pressure and low temperature conditions, small molecular gases are fixed in crystal cages composed of water molecules to form solid hydrates. Figure 1 Phase diagrams for CO2 and natural gas are compared. If seafloor conditions (pressure and temperature) are above the CO2 equilibrium curve, CO2 hydrates are expected to form. The rate of hydrate formation depends on seafloor conditions and the degree of mixing of the gas with seawater. This principle has been verified in previous studies. However, it takes time for CO2 molecules to fully contact water molecules to form hydrates. If CO2 is released directly to the seafloor, the free CO2 will rise because its density is lower than that of water. Even if CO2 dissolves in seawater during its rise, it will have a negative impact on the seawater environment.

[0024] The equipment of the present invention is installed on a ship 1, wherein CO2 is transported to a CO2 storage tank 3 through a liquid CO2 connection device 2, cooled by a CO2 cooler 4 to increase density, pumped by a CO2 pump 5 into a flexible hose 6, and enters a CO2 injection head 7. The variable frequency motor 17 inside the injection head drives a stirring paddle 18 to stir and disperse the liquid CO2 more evenly, preventing the CO2 liquid from aggregating in large quantities in the injection head to form hydrates. The dispersed liquid CO2 is fully injected into the seabed through a nozzle 8. Due to the Joule-Thomson cooling effect, the injected CO2 flow should be in a super-cold state and immediately form CO2 hydrates with seawater. The flowmeter displays the flow of liquid CO2, the temperature and pressure sensor 20 obtains the pressure and temperature of the injection head, and the current rate of liquid CO2 delivery is determined by the hydrate formation conditions. The CO2 flow is controlled by the first one-way valve 16-1 and the first flowmeter 15-1 to ensure the hydrate formation rate. When hydrate blocks the nozzle, the hydrate inhibitor injection is controlled by the second one-way valve 16-2 and the second flowmeter 15-2 to prevent and control hydrate or unblock the nozzle. The inhibitor container is connected to the sensor to ensure timely replenishment of the inhibitor capacity and the normal operation of the device. If a part of the carbon dioxide flow is still free, it should form hydrates under the buffer plate 9. The depth control room 10 will receive the readings of the sonar depth sounder 11 and adjust the position of the nozzle 7 to bring it closer to the seabed. When free CO2 is detected, the CO2 monitoring room 12 receives the readings of the CO2 detector 13 and sends a signal to the CO2 pump controller to reduce the CO2 injection rate. The formed carbon dioxide hydrate should remain on the seabed because its density is higher than that of seawater.

[0025] See also Figure 3The ship is mobile and is loaded with liquid CO2 from the carrier hose to the CO2 tank. The CO2 is pressurized and encrypted by a cooler to reach a supercritical state, that is, it is converted from gas to liquid. The cooled CO2 is pumped into the hose by the CO2 pump and enters the injection head. Due to the Joule-Thomson effect, the CO2 gas expands through the porous plug injection nozzle, causing a temperature change and forming CO2 hydrate. The gas transmission process does not require drilling, and the hose cost is low.

[0026] Figure 4 The depth control room receives the seawater depth data from the sonar depth sounder and adjusts the position of the injection head according to the data so that the injection head is close to the seabed for CO2 storage.

[0027] Figure 5 It is a schematic diagram of the CO2 monitoring system of the present invention. No matter in what form CO2 is sealed in the ocean, a certain degree of leakage will occur. The release process of CO2 after sealing in the ocean is extremely slow, but its leakage risk cannot be ignored, including leakage during transportation and injection before sealing. Once CO2 leaks, it will first cause seawater acidification, and then destroy the balance of the marine ecosystem and threaten the diversity of marine life. The CO2 detector detects parameters such as the concentration of CO2 indicators and the pH value of seawater. These parameters will change synchronously with the leakage of CO2. The detector detects the changes in indicators and uploads them to the CO2 detection room, so as to quickly adjust the pumping rate of the CO2 pump to protect the safety of the marine environment.

[0028] See also Figure 6 , a variable frequency motor 17 is arranged inside the nozzle to drive the stirring paddle 18 to stir and disperse the liquid CO2, so as to prevent the CO2 liquid from aggregating in large quantities in the nozzle to form hydrates and block the nozzle. The dispersed liquid CO2 is fully injected into the seabed through the nozzle 8. Due to the Joule-Thomson cooling effect, the injected CO2 flow should be in a super-cold state and immediately form CO2 hydrates with seawater. The first flowmeter 15-1 displays the flow of liquid CO2, and the temperature and pressure sensor 20 transmits the pressure and temperature data of the nozzle to the CO2 monitoring room; the CO2 monitoring room controls the rate of liquid CO2 by controlling the first one-way valve 16-1 through the hydrate formation conditions to ensure the hydrate formation rate. If CO2 hydrate blocks the nozzle and the temperature and pressure sensor data is abnormal, the CO2 monitoring room controls the opening of the one-way valve 16-2, injects hydrate inhibitors into the nozzle, and performs hydrate prevention and control or unblocking. The liquid level sensor is responsible for transmitting information to the control room to replenish the container inhibitor in time, thereby ensuring the normal operation of the device. If a part of the carbon dioxide flow is still free, it should form hydrates under the buffer plate 9.

[0029] In the present invention, the ship is loaded with liquid CO2 from a CO2 carrier or a pipeline hose to a CO2 storage tank 3. The liquid CO2 is cooled by a cooler 4 to increase the density. The cooled carbon dioxide is pumped into a hose 6 by a pump 5 and enters an injection head 7, where the carbon dioxide is stirred and dispersed by a stirring paddle and expanded through an injection nozzle 8. Due to the Joule-Thomson cooling effect, the injected CO2 stream should be further cooled below the seawater temperature, thereby immediately forming CO2 hydrates. If there is any remaining carbon dioxide, hydrates will be formed under the buffer plate 9. The depth control room 10 receives seawater depth data from a sonar depth sounder 11 and adjusts the position of the injection head 7 to make it close to the seabed. The CO2 monitoring room 12 receives data from a CO2 detector 13, and when free carbon dioxide is detected, a signal is sent to the CO2 pump controller to reduce the CO2 injection rate. The formed CO2 hydrate remains on the seabed because its density is higher than that of seawater. According to actual needs, the ship will move forward slowly.

[0030] The mobile injection method of the mobile injection device for solidifying carbon dioxide on the seabed: When the ship moves in the seawater, the CO2 injection head is placed in the seawater, and then the depth of the CO2 injection head in the seawater is adjusted by the depth control system through the steel wire rope, and the CO2 detector is placed in the seawater at the same time; CO2 is pressurized and encrypted through a CO2 cooler, so that carbon dioxide reaches a supercritical state, so that the ship is loaded with high-density liquid CO2. The cooled CO2 is pumped into a flexible hose by a CO2 pump. CO2 is transmitted to the seabed through the flexible hose, enters the CO2 injection head, and expands and sprays out through the injection nozzle, immediately forming CO2 hydrates. CO2 that has not formed hydrates will form hydrates under the buffer plate; when the ship moves, the depth control room receives seawater depth data and adjusts the position of the CO2 injection head in real time to make it close to the seabed. At the same time, the CO2 monitoring room receives seawater CO2 concentration data. When free CO2 is detected, a signal is sent to the CO2 pump controller to control the CO2 injection rate; the formed CO2 hydrates remain on the seabed because their density is higher than that of seawater, realizing the seabed storage of CO2; The variable frequency motor of the CO2 injection head drives the stirring paddle to stir, so that the CO2 injection head is always evenly dispersed in liquid CO2, preventing the CO2 liquid from aggregating in large quantities in the CO2 injection head to form hydrates; The temperature and pressure sensor collects the pressure and temperature of the CO2 injection head, and determines the current rate of liquid CO2 delivery based on the hydrate formation conditions. When hydrates block the CO2 injection head, the injection of hydrate inhibitor is controlled through the second one-way valve and the second flowmeter to prevent and control hydrates or unblock them. The inhibitor container liquid level sensor detects that the hydrate inhibitor is too little and replenishes the inhibitor in time.

[0031] In the present invention, CO2 is transmitted to the seabed through a flexible hose without drilling. When the ship moves, the depth control room receives the seawater depth data from the sonar depth sounder, and adjusts the position and depth of the injection head according to the data; when the ship moves, the CO2 monitoring room receives the CO2 concentration data from the CO2 detector, and controls the CO2 injection rate; the free CO2 is covered with a buffer plate, so that the free CO2 that does not immediately generate hydrate has more time to be converted into CO2 hydrate; the sonar depth sounder is used to collect the seabed depth data, and the injection head position and depth are adjusted according to the seabed depth data; the CO2 detector is used to collect the ocean CO2 concentration, and the CO2 pumping rate is adjusted according to the CO2 concentration data.

[0032] The flexible hose of the present invention is resistant to tension, corrosion, low temperature and high pressure. The CO2 injection head is a Φ150mm injection head, the blade diameter of the stirring paddle is 50mm, and the buffer plate is a 300mm×300mm flat plate.

Claims

1. A mobile injection device for solidifying carbon dioxide on the seabed, characterized in that: This mobile injection device for solidifying carbon dioxide on the seabed includes a ship, on which a CO2 storage tank, a CO2 cooler, a CO2 pump, a depth control system, and a CO2 monitoring system are arranged. The CO2 storage tank, the CO2 cooler, and the CO2 pump are connected in sequence, and the CO2 pump is connected to the CO2 injection head through a flexible hose. The depth control system includes a depth control room, in which a drum is arranged, one end of a steel wire rope is fixed on the drum, and the other end of the steel wire rope is fixed on the flexible hose. The drum is connected to a winch motor, and a depth controller in the depth control room is connected to a sonar depth sounder through a cable. The depth of the CO2 injection head lowered into the seawater is controlled by retracting and releasing the steel wire rope, and the position of the CO2 injection head is adjusted in real time to make it close to the seabed; the CO2 monitoring system includes a CO2 monitoring room, The CO2 monitoring room is provided with a monitoring controller, which is connected to the CO2 detector through a retractable cable. By controlling the retractable cable, the depth of the CO2 detector lowered into the seawater is controlled in real time, and the CO2 concentration in the ocean is monitored in real time; the CO2 injection head includes an injection shell, an injection chamber, an injection nozzle, a buffer plate, a stirring motor, and an inhibitor container. An annular buffer plate is arranged outside the injection shell, the buffer plate is located above the injection nozzle and covers the injection nozzle underneath, a stirring paddle is arranged in the injection chamber, an inhibitor container is arranged on the top of the injection shell, a liquid level sensor is arranged at the bottom of the inhibitor container, a hydrate inhibitor is contained in the inhibitor container, the inhibitor container is connected to the inhibitor inlet on the top of the injection shell, a second one-way valve and a second flowmeter are installed at the inhibitor inlet, and a temperature and pressure sensor is also installed on the injection shell.

2. The mobile injection device for solidifying carbon dioxide on the seabed according to claim 1, characterized in that: The stirring paddle is connected to a variable frequency motor, and the variable frequency motor is arranged on the top of the injection shell.

3. The mobile injection device for solidifying carbon dioxide on the seabed according to claim 2, characterized in that: A first one-way valve is arranged on the top of the injection shell, the end of the flexible hose is connected to the first one-way valve, and the end of the flexible hose is installed with a first flow meter.

4. The mobile injection device for solidifying carbon dioxide on the seabed according to claim 3, characterized in that: The inlet of the CO2 storage tank is connected to the CO2 connecting device, and the CO2 is stored in the CO2 storage tank through the CO2 connecting device.

5. A mobile spraying method of a mobile spraying device for solidifying carbon dioxide on a seabed according to claim 4, characterized in that: When the ship moves in the seawater, the CO2 injection head is placed in the seawater, and then the depth of the CO2 injection head in the seawater is adjusted by the depth control system through the steel wire rope, and the CO2 detector is placed in the seawater at the same time; CO2 is pressurized and encrypted through a CO2 cooler, so that carbon dioxide reaches a supercritical state, so that the ship is loaded with high-density liquid CO2. The cooled CO2 is pumped into a flexible hose by a CO2 pump. CO2 is transmitted to the seabed through the flexible hose, enters the CO2 injection head, and expands and sprays out through the injection nozzle, immediately forming CO2 hydrates on the seabed. CO2 that has not formed hydrates will form hydrates under the buffer plate; when the ship moves, the depth control room receives seawater depth data and adjusts the position of the CO2 injection head in real time to make it close to the seabed. At the same time, the CO2 monitoring room receives seawater CO2 concentration data. When free CO2 is detected, a signal is sent to the CO2 pump controller to control the CO2 injection rate; the formed CO2 hydrates remain on the seabed because their density is higher than that of seawater, realizing the seabed storage of CO2; The variable frequency motor of the CO2 injection head drives the stirring paddle to stir, so that the CO2 injection head is always evenly dispersed in liquid CO2, preventing the CO2 liquid from aggregating in large quantities in the CO2 injection head to form hydrates; The temperature and pressure sensor collects the pressure and temperature of the CO2 injection head, and determines the current rate of liquid CO2 delivery based on the hydrate formation conditions. When hydrates block the CO2 injection head, the injection of hydrate inhibitor is controlled through the second one-way valve and the second flowmeter to prevent and control hydrates or unblock them. The inhibitor container liquid level sensor detects that the hydrate inhibitor is too little and replenishes the inhibitor in time.

6. The mobile injection method of the mobile injection device for solidifying carbon dioxide on the seabed according to claim 5, characterized in that: Covering the free CO2 with a buffer plate allows the free CO2 that does not immediately form hydrates to have more time to be converted into CO2 hydrates.

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