Deep sea polymetallic nodule boiling type lifting system and lifting method

Abstract

The invention discloses a deep sea polymetallic nodule boiling type lifting system which comprises a collecting platform on the sea surface and a relay station suspending in the sea, the relay station is communicated with the collecting platform through a pipeline, the pipeline comprises a plurality of sections of lifting vertical pipes, and every two adjacent sections of lifting vertical pipes are connected through a boiling type heating device. The boiling type heating devices are the same in structure. The lifting system disclosed by the invention integrates the technical characteristics of the existing pipeline conveying technology, and is simple in structure and high in reliability. Liquid phase vaporization is used as a gas phase source in a pipeline, a boiling type heating device with a metal heating pipe and a heat insulation layer is directly connected with a lifting vertical pipe, and meanwhile, a plurality of sections of boiling type heating devices are arranged in the pipeline, so that the stability of providing gas phase power is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of seabed mining, and in particular relates to a deep-sea polymetallic nodule boiling lifting system and a lifting method in the field. Background Art

[0002] Lithium, nickel, cobalt, and manganese are the core elements for making efficient energy storage batteries. They are found in large quantities in polymetallic nodules on the seafloor. However, the commercial exploitation of polymetallic nodules on the seafloor still needs to overcome many technical obstacles. In particular, how to transport polymetallic nodules from the seafloor to the sea surface collection ship in an economic, safe, and environmentally friendly manner is one of the key links that needs to be overcome urgently, which is full of technical challenges. First, the seafloor polymetallic nodules need to be lifted vertically thousands of meters during the mining process, which consumes a lot of energy. Improving the transportation efficiency of this link will greatly reduce the economic cost of the mining process. Secondly, in order to meet the ore processing needs of the rear smelter and minimize the scale of ore stockpiling, the output of polymetallic nodules should be guaranteed to be stable, which requires the transportation system to be able to continuously transport polymetallic nodules. Third, the transportation range of polymetallic nodules extends from thousands of meters deep on the seafloor to the sea surface, covering a wide area and a harsh working environment. Once a production accident occurs, it will have a great impact on the ecological environment of the sea area, which places extremely high demands on the reliability and risk management capabilities of the transportation system.

[0003] At present, the mainstream lifting method in the world is pipeline lifting, which is to use deep-sea vertical pipelines to establish a connection between the seabed mining vehicle and the sea surface transport ship, and to transfer the collected deep-sea polymetallic nodules from the seabed to the transport ship through the pipeline. Pipeline lifting methods are divided into pneumatic lifting and hydraulic lifting. Pneumatic lifting is to input gas into the transport pipeline through a compressor, and use the potential energy difference of the fluid inside and outside the transport pipeline and the kinetic energy of the air pressure to lift the minerals from the seabed to the sea surface. Hydraulic lifting is to lift the minerals to the sea surface through a slurry delivery pump connected in series to the pipeline.

[0004] The main problems of hydraulic lifting systems are coarse particle overflow, power supply and pump wear. In order to ensure the yield of polymetallic nodules and avoid particle collision and crushing that makes it difficult to recover, the diameter of the nodules is generally 20-40mm. However, the channel in the positive displacement pump of the hydraulic lifting system is relatively thin, which does not allow the overflow of larger particles. The multi-stage volute centrifugal pump in series is prone to cable entanglement underwater. Even if the multi-stage space guide vane centrifugal pump currently under research can solve the above two problems, the abrasion of particles on the various components of the lifting pump equipment cannot be ignored. During maintenance, the pump and several kilometers of pipelines need to be recovered from the seabed to the mining ship. In addition, due to the impeller movement and complex flow channels of the centrifugal pump, the damage and pulverization of nodules in the pump will be far more serious than in the pipeline, resulting in resource recovery losses and environmental pollution.

[0005] Compared with the hydraulic lifting system, the pneumatic lifting system reduces the impact of particles on equipment abrasion. However, the air compressor is used to inject gas into the water. Since the gas flow rate is difficult to control, the flow state of the multiphase flow is difficult to maintain. At the inlet of the compressed air, bubble flow may be generated due to high air pressure. This flow state is the mainstream state for lifting metal nodules. When the three-phase flow in the pipe moves upward for a certain distance, the bubbles increase as the pressure decreases, thereby forming a ring flow and other flow states that are not conducive to polymetallic nodules. In order to ensure the stable transportation of the pipeline, it is necessary to expand the diameter of the upper part of the pipeline, which reduces the stability of pipeline transportation and increases the equipment cost. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a deep-sea polymetallic nodule boiling lifting system and lifting method, which avoids the serious abrasive effects of particles on pipelines, overcomes the instability of flow shape and flow state, reduces production costs, improves system stability, and realizes the transportation of larger-scale particles.

[0007] The present invention adopts the following technical solution: A deep-sea polymetallic nodule boiling lifting system, the improvement of which lies in: comprising a collection platform on the sea surface and a relay station suspended in the sea, the relay station and the collection platform being connected by a pipeline, the pipeline comprising a plurality of lifting risers, two adjacent lifting risers being connected by a boiling heating device, the boiling heating devices having the same structure, comprising a metal heating pipe, a heat insulation layer covering the outside of the metal heating pipe, an insulating material layer covering the outside of the heat insulation layer, a protective layer covering the outside of the insulating material layer, a copper coil wrapped around the heat insulation layer embedded in the insulating material layer, the copper wire ends at both ends of the copper coil exposed outside the pipe wall of the protective layer and wrapped by the insulating material, an energy supply device being electrically connected to the copper wire ends of each boiling heating device in parallel through a deep-sea cable, and the relay station being also connected to the collection device of a seabed mining vehicle through a ore collecting hose.

[0008] Furthermore, the exterior of the relay station is an open frame structure, the top end of which is connected to the lifting riser through a cross-hinged swing connection device, and the center position of the bottom end is connected to the ore-collecting hose through a flange.

[0009] Furthermore, the lifting standpipe is connected to the boiling heating device by a flange.

[0010] Furthermore, the energy supply device is arranged on the collection platform on the sea surface, and supplies power to each boiling heating device through a frequency conversion circuit, and the power supply is controlled by a control system.

[0011] Furthermore, the frequency conversion circuit includes an alternating circuit consisting of two inductors, a capacitor and two resistors, a diode and a MOS tube, one end of the alternating circuit is electrically connected to the positive electrode, and the other end is electrically connected to the negative electrode.

[0012] A lifting method uses the above-mentioned lifting system, and its improvement lies in that: after the lifting system is installed in place, the polymetallic nodule particles mined by the seabed mining vehicle are transported to the relay station via the ore collecting hose, and the energy supply device starts to supply power to the copper wire heads of each boiling heating device, so that the copper coil is energized to form an internal magnetic field with high frequency conversion, and the metal heating tube in the copper coil forms a short circuit based on electromagnetic induction, so that the tube wall of the metal heating tube is heated, and heat exchange occurs with the liquid inside the metal heating tube, so that the internal liquid boils and gushes upward, and at the same time, the internal liquid generates boiling bubbles that move upward, and the boiling bubbles interact with the internal liquid to further provide power for the internal liquid to flow upward, and the internal liquid flowing upward drives the polymetallic nodule particles in the relay station to move upward at a certain concentration until they reach the collection platform on the sea surface.

[0013] Furthermore, the energy supply device converts the direct current into a high-frequency alternating current.

[0014] Furthermore, the interaction forces between bubbles and the internal liquid include drag force, lift force, wall lubrication force, virtual mass force and turbulent dissipation force.

[0015] Furthermore, the lifting speed and efficiency of the polymetallic nodule particles can be controlled by controlling the heating efficiency of the boiling heating device.

[0016] The beneficial effects of the present invention are: The lifting system disclosed in the present invention integrates the technical features of the existing pipeline transportation technology, has a simple structure and high reliability. Liquid phase vaporization is used as the gas phase source in the pipeline, and a boiling heating device with a metal heating pipe and a heat insulation layer is directly connected to the lifting riser. At the same time, multiple sections of boiling heating devices are arranged in the pipeline to ensure the stability of providing gas phase power. The energy supply device with a complex structure is arranged on the collection platform on the sea surface, which is convenient for safety inspection and maintenance and reduces maintenance costs.

[0017] Compared with the pump-type hydraulic pipeline lifting system, the lifting system of the present invention uses long and straight pipelines with uniform diameters, which has better applicability to large-sized particles and reduces the risk of blockage. Compared with the air compressor-type pneumatic pipeline lifting system: the lifting system of the present invention does not require an air compressor, which reduces production costs.

[0018] The lifting method disclosed in the present invention uses the interaction force between bubbles and liquid as the direct power source for the upward movement of polymetallic nodule particles in the pipeline, without the need for a slurry lifting pump, thereby reducing the abrasion of particles. The bubbles automatically disappear after rising a certain distance, thus avoiding the bubbles from gathering at the upper end of the pipeline to form annular flow and other flow states that are not conducive to particle transportation, and does not affect production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic diagram of the overall structure of the lifting system disclosed in the present invention; Figure 2 It is a structural schematic diagram of a boiling heating device in a lifting system disclosed in the present invention; Figure 3 It is a schematic diagram of the composition of the frequency conversion circuit in the lifting system disclosed by the present invention.

[0020] Reference numerals: 1—energy supply device, 11—frequency conversion circuit, 2—boiling heating device, 21—metal heating tube, 22—thermal insulation layer, 23—insulating material layer, 24—protective layer, 25—copper coil, 26—copper wire head, 3—lifting riser, 4—relay station, 5—ore collection hose, 6—mining vehicle, 7—deep-sea cable. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Example 1: This example discloses a deep-sea polymetallic nodule boiling lifting system. Figure 1 As shown, it includes a collection platform on the sea surface and a relay station 4 suspended in the sea. The collection platform can be a mining ship or a mining platform. The relay station and the collection platform are connected through a pipeline. The pipeline includes a plurality of sections of lifting risers 3. Two adjacent sections of lifting risers are connected through a boiling heating device 2. Figure 2 As shown, the structures of the boiling heating devices are the same, and are all composed of a four-layer tube wall structure, including a metal heating tube 21, a heat insulation layer 22 covered on the outside of the metal heating tube, an insulating material layer 23 covered on the outside of the heat insulation layer, a protective layer 24 covered on the outside of the insulating material layer, and a copper coil 25 wrapped around the heat insulation layer embedded in the insulating material layer. The copper wire ends 26 at both ends of the copper coil are exposed outside the tube wall of the protective layer and are wrapped by thickened insulating material. The energy supply device 1 is electrically connected to the copper wire ends of each boiling heating device in parallel through a deep-sea cable 7 to realize power supply to the boiling heating device. The relay station is also connected to the collection device of the seabed mining vehicle 6 through a ore collecting hose 5.

[0023] In this embodiment, the exterior of the relay station is an open frame structure, the top of which is connected to the lifting riser through a cross-hinged swing connection device to enable the relay station to swing with two degrees of freedom around the end of the lifting riser, and the center position of the bottom end is connected to the ore collecting hose through a flange.

[0024] The lifting standpipe is connected to the boiling heating device by a flange.

[0025] The energy supply device is arranged on the collection platform on the sea surface, and supplies power to each boiling heating device through the frequency conversion circuit 11, and the power supply is controlled by the control system. The electric energy of the energy supply device can be converted from tidal energy or ocean energy nearby, or it can be clean energy generation, fossil energy generation or nuclear energy generation from the shore.

[0026] like Figure 3 As shown, the frequency conversion circuit includes two inductors, a capacitor and an alternating circuit composed of two resistors, a diode and a MOS tube. One end of the alternating circuit is electrically connected to the positive electrode and the other end is electrically connected to the negative electrode, and is used to convert direct current into high-frequency alternating current.

[0027] The lifting system of this embodiment utilizes the principles of electromagnetic induction heating and supercooled boiling to energize the copper coil of the boiling heating device, and convert the direct current into high-frequency alternating current through the frequency conversion circuit of the energy supply device. A magnetic field that changes periodically and in the opposite direction at high frequency is generated inside the copper coil. Due to the change in magnetic flux, a short-circuit eddy current is formed inside the metal heating tube of the boiling heating device, which generates a large amount of heat and heats up rapidly. The internal liquid in contact with the tube wall begins to boil locally, gushing upward and generating a large number of bubbles to drive the overall upward movement of the liquid in the pipeline, thereby realizing the transportation of the polymetallic nodules by the liquid in the pipeline.

[0028] The present embodiment also discloses a lifting method, using the above-mentioned lifting system. After the lifting system is installed in place, the polymetallic nodule particles mined by the seabed mining vehicle are transported to the relay station via the ore collecting hose, and the energy supply device begins to supply power to the copper wire heads of each boiling heating device through the deep-sea cable, so that the copper coil is energized to form an internal magnetic field with a high frequency conversion, and the metal heating tube in the copper coil forms a short circuit based on electromagnetic induction, so that the tube wall of the metal heating tube begins to generate eddy currents and heats up rapidly, and heat exchanges occur with the liquid inside the metal heating tube, causing the internal liquid to boil and gush upward, and at the same time, the internal liquid generates boiling bubbles that move upward, and the boiling bubbles interact with the internal liquid to further provide power for the internal liquid to flow upward, and the upward flowing internal liquid drives the polymetallic nodule particles in the relay station to move upward at a certain concentration until they reach the collection platform on the sea surface, thereby realizing continuous and stable mining.

[0029] In this embodiment, the energy supply device converts direct current into high-frequency alternating current.

[0030] The interaction forces between bubbles and the internal liquid include drag force, lift force, wall lubrication force, virtual mass force and turbulent dissipation force.

[0031] The lifting speed and efficiency of the polymetallic nodule particles can be controlled by controlling the heating efficiency of the boiling heating device.

Claims

1. A deep-sea polymetallic nodule boiling lifting system, characterized by: The invention comprises a collection platform on the sea surface and a relay station suspended in the sea. The relay station and the collection platform are connected by a pipeline. The pipeline comprises a plurality of sections of lifting risers. Two adjacent sections of the lifting risers are connected by a boiling heating device. The boiling heating devices have the same structure and comprise a metal heating pipe. A heat insulation layer is covered on the outside of the metal heating pipe, an insulating material layer is covered on the outside of the heat insulation layer, a protective layer is covered on the outside of the insulating material layer, a copper coil wrapped around the heat insulation layer is embedded in the insulating material layer, the copper wire ends at both ends of the copper coil are exposed outside the pipe wall of the protective layer and are wrapped by the insulating material, an energy supply device is electrically connected to the copper wire ends of each boiling heating device in parallel through a deep-sea cable, and the relay station is also connected to the collection device of the seabed mining vehicle through a ore collecting hose.

2. The deep-sea polymetallic nodule boiling lifting system according to claim 1 is characterized in that: The outside of the relay station is an open frame structure, the top of which is connected to the lifting riser through a cross-hinged swing connection device, and the center of the bottom is connected to the ore-collecting hose through a flange.

3. The deep-sea polymetallic nodule boiling lifting system according to claim 1 is characterized in that: The lifting standpipe is connected to the boiling heating device by a flange.

4. The deep-sea polymetallic nodule boiling lifting system according to claim 1 is characterized in that: The energy supply device is arranged on a collection platform on the sea surface, and supplies power to each boiling heating device through a frequency conversion circuit, and the power supply is controlled by a control system.

5. The deep-sea polymetallic nodule boiling lifting system according to claim 4 is characterized in that: The frequency conversion circuit comprises an alternating circuit consisting of two inductors, a capacitor and two resistors, a diode and a MOS tube. One end of the alternating circuit is electrically connected to the positive electrode, and the other end is electrically connected to the negative electrode.

6. A lifting method, using the lifting system according to claim 1, characterized in that: After the lifting system is installed in place, the polymetallic nodule particles mined by the seabed mining vehicle are transported to the relay station through the ore collecting hose. The energy supply device begins to supply power to the copper wire heads of each boiling heating device, so that the copper coil is energized to form an internal magnetic field with a high frequency conversion. The metal heating tube in the copper coil forms a short circuit based on electromagnetic induction, which heats up the tube wall of the metal heating tube and exchanges heat with the liquid inside the metal heating tube, causing the internal liquid to boil and gush upward. At the same time, the internal liquid also generates boiling bubbles that move upward. The boiling bubbles then interact with the internal liquid to further provide power for the internal liquid to flow upward. The upward flowing internal liquid drives the polymetallic nodule particles in the relay station to move upward at a certain concentration until they reach the collection platform on the sea surface.

7. The lifting method according to claim 6, characterized in that: The energy supply device converts direct current into high-frequency alternating current.

8. The lifting method according to claim 6, characterized in that: The interaction forces between bubbles and the internal liquid include drag force, lift force, wall lubrication force, virtual mass force and turbulent dissipation force.

9. The lifting method according to claim 6, characterized in that: The lifting speed and efficiency of the polymetallic nodule particles can be controlled by controlling the heating efficiency of the boiling heating device.

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