Device and method for suppressing sediment discharge plume from seabed mining vehicle

Abstract

The present invention discloses a device and method for suppressing sediment discharge plume flow applicable to a seabed mining vehicle, comprising a physical screening system, a biological flocculation sedimentation system, and a sediment discharge system; the physical screening system can realize the separation of seabed minerals and deep-sea sediments in the body of the mining vehicle, further filter out sediments with larger particle sizes through physical screening, and mix sediments with smaller particle sizes with seawater; the method of adding flocculants through the biological flocculation sedimentation system is used to precipitate sediments with small particle sizes in seawater, and finally the sediments are discharged from the sediment discharge system close to the seabed, thereby reducing the plume flow generated when the mining vehicle discharges sediments.

Description

Technical Field

[0001] The present invention belongs to the technical field of seabed mining, and in particular relates to a device and method for suppressing sediment discharge plume of a seabed mining vehicle. Background Art

[0002] At present, due to the saturation of land mineral resources and the scarcity of seabed mineral resources (such as nickel, chromium and other rare metal elements), people are gradually turning their attention to marine mineral resources. Seabed mining is a technology with significant economic benefits. Its essence is to extract mineral resources from the seabed and then transport them to factories for further processing and treatment. However, if there is no proper mining method, it will have no value and will cause irreversible impacts on the marine environment.

[0003] When mining vehicles are mining on the seabed, they will cause sediments or liquid gases on the seabed to suspend, thus forming plumes, which will have irreversible effects on animals or sessile organisms in the mining area and surrounding areas, and even cause their death. At present, domestic and foreign scholars have conducted a lot of research on the suppression of plumes, but the formation of plumes is a complex process, and its results may affect the efficiency and environmental protection of seabed mining operations. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a device and method for suppressing the plume flow of sediment discharge from a seabed mining vehicle, which can separate seabed minerals from deep-sea sediments in the body of the mining vehicle, further filter out sediments with larger particle sizes through physical screening, and mix sediments with smaller particle sizes with seawater, and precipitate sediments with small particle sizes in seawater by adding flocculants, and finally discharge them close to the seabed, thereby reducing the plume flow generated when the mining vehicle discharges sediments.

[0005] The present invention is achieved through the following technical solutions:

[0006] A sediment discharge plume suppression device for a seabed mining vehicle, characterized in that it comprises: a physical screening system, a biological flocculation and sedimentation system, and a sediment discharge system;

[0007] The physical screening system is composed of a collector, a filtering device and a lifting device. The filtering device is provided with an arc-shaped filtering screen for separating polymetallic nodule sediments. The lifting device is a riser in a deep-sea mining system for lifting polymetallic nodules, which is connected to a mining ship to transport the collected polymetallic nodules to the mining ship.

[0008] The biological flocculation sedimentation system is composed of a flocculant storage box, a flocculation box, and a static box. The flocculant storage box stores biological flocculants and is connected to the flocculation box through a delivery pipe. The flocculation box is used to mix sediments and biological flocculants. There are three static boxes, which work independently. A pumping device is provided on the top of the static box, and the bottom is an openable bottom plate.

[0009] The sediment discharge system includes a purified seawater discharge system and a sediment solid discharge system. The purified seawater discharge system consists of a pumping device and a drainage pipe. The pumping device is controlled to discharge the purified seawater through the drainage pipe to more than 10m below the seabed. The sediment solid discharge system consists of a bottom plate and a discharge pipe, which is used to control the bottom plate of the static box and discharge the solid sediment close to the seabed through the sediment discharge pipe.

[0010] Furthermore, the results of on-site investigations and indoor tests show that polymetallic nodules are mainly spherical and ellipsoidal in shape, with an average diameter of about 4 cm. The arc-shaped filter has a diameter of 2 cm, which can filter out all the polymetallic nodules and lift them to the mining ship.

[0011] Furthermore, the large particle sediment screening net is used to screen the large particle sediment insoluble in water and discharge it from the vehicle body through the sediment discharge pipe.

[0012] Furthermore, the flocculation box is provided with a stirrer for uniformly mixing the biological flocculant and the sediment, thereby achieving an effective and rapid sedimentation effect.

[0013] Furthermore, the bioflocculant is a new type of flocculant, and its ingredients may contain biological protein, microbial flora, animal and plant extracts, etc. The bioflocculant can inhibit sediment expansion, improve sediment settling properties, and will not cause further chemical pollution to the environment.

[0014] Furthermore, the standing box contains a mixture of sediment and biological flocculant, which is evenly mixed by a stirrer in the flocculation box. The standing box has three working states: water delivery, standing, and discharge, and the three standing boxes are respectively in three different working states: water delivery, standing, and discharge.

[0015] Furthermore, the purified seawater discharge system is responsible for controlling the pumping device. When the static tank is in the discharge state, the purified seawater discharge system controls the pumping device to extract 90% of the volume of the purified seawater in the static tank and discharge it through the drain pipe to the sea area more than 10m away from the seabed, and controls the drainage speed according to the collection speed.

[0016] Furthermore, the sediment solid discharge system is to control the bottom plate of the still box to open after the still box is drained, so that the sediment is discharged from the sediment discharge pipe at the bottom of the mining vehicle close to the seabed.

[0017] A method for suppressing sediment discharge plume from a seabed mining vehicle is implemented by using the sediment discharge plume suppression device for a seabed mining vehicle according to the present invention. The method comprises the following steps:

[0018] Step 1: When the mining vehicle is mining through the collector, the polymetallic nodules and sediments are collected into the mining vehicle at the same time. The polymetallic nodules and sediments first enter the physical screening system and are screened in the filtering device through an arc filter with a diameter of about 2 cm;

[0019] Step 2: The polymetallic nodules are filtered out and enter the lifting device, where they are lifted to the mining ship by the riser, while the sediments pass through the curved filter screen and enter the bioflocculation sedimentation system;

[0020] Step 3: The bioflocculant enters the flocculation tank from the flocculant storage tank and mixes with the sediment. The agitator in the flocculation tank rotates to fully mix the bioflocculant and the sediment.

[0021] Step 4: The three static tanks are respectively in three different working states: water delivery, static, and discharge. The mixture of bioflocculant and sediment first flows into static tank 1. When static tank 1 is full, it will change from the water delivery state to the static state, and the mixture of bioflocculant and sediment will flow into static tank 2.

[0022] Step 5: When the static tank 2 is full, it will change from the water delivery state to the static state, the bioflocculant and sediment mixture will flow into the static tank 3, and the static tank 1 will change from the static state to the discharge state. The three static tanks operate in this order;

[0023] Step 6: The purified seawater discharge system of the sediment discharge system is responsible for controlling the pumping device to extract 90% of the volume of purified seawater in the static tank 1, and discharge it to the sea area more than 10m away from the seabed through the drainage pipe, and control the drainage speed according to the collection speed;

[0024] Step 7: After the drainage of the settling box is completed, the bottom plate of the settling box is controlled to open, and the sediment is discharged from the sediment discharge pipe at the bottom of the mining vehicle close to the seabed.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. There are two main ways for deep-sea mining operations to generate plumes: mining vehicle movement and turbid water discharge. The focus of existing technologies and patents is on controlling the plumes generated by mining vehicles and reducing the plumes generated by movement. The present invention provides a plume suppression device for sediment discharge from a seabed mining vehicle, which eliminates the generation of plumes caused by turbid water discharge from the source;

[0027] 2. In order to reduce the impact of plumes on the environment, deep-sea mining operations use flocculants to suppress the plumes that have already been generated, but the flocculants and plumes cannot fully react, and may cause further chemical pollution to the environment. The present invention uses a new type of biological flocculant to eliminate chemical pollution and control the occurrence of flocculation reactions within the vehicle body;

[0028] 3. In order to make the flocculation reaction more complete, the present invention installs a stirrer in the flocculation box and sets three static boxes to increase the flocculation reaction time and precipitate all the sediments;

[0029] 4. In order to prevent the generation of secondary plumes when discharging sediments, the present invention discharges purified seawater and sediments separately. The purified seawater is discharged to the sea area more than 10m away from the seabed through a drainage pipe, and the sediments are discharged from the sediment discharge pipe at the bottom of the mining vehicle close to the seabed, eliminating the possibility of secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the overall system of a sediment discharge plume suppression device for a seabed mining vehicle provided in an embodiment of the present invention.

[0031] Figure 2 A schematic structural diagram of a sediment discharge plume suppression device for a seabed mining vehicle provided in an embodiment of the present invention.

[0032] Figure 3 A schematic diagram of the structure of an arc-shaped filter screen of a physical screening system provided in an embodiment of the present invention.

[0033] Figure 4 A schematic diagram of the structure of a mixer of a biological flocculation and sedimentation system provided in an embodiment of the present invention.

[0034] Figure 5 A schematic structural diagram of a sediment discharge system provided in an embodiment of the present invention.

[0035] In the figure: 1. physical screening system; 2. biological flocculation sedimentation system; 3. sediment discharge system; 101. collector; 102. filtering device; 103. lifting device; 104. arc filter; 105. large particle sediment screening net; 201. flocculant storage box; 202. flocculation box; 203. static box; 204. delivery pipe; 205. mixer; 303. pumping device; 304. bottom plate; 305. drain pipe; 306. sediment discharge pipe. Implementation

[0036] The present invention is further described below in conjunction with the embodiments, but it should not be understood that the above subject matter of the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various substitutions and changes are made according to the common technical knowledge and customary means in the field, which should all be included in the protection scope of the present invention.

[0037] In addition, in the description of the present invention, it should be understood that the terms "center", "inside", "up", "down", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0038] like Figure 1 As shown, the present invention discloses a sediment discharge plume suppression device for a seabed mining vehicle, which comprises three parts: a physical screening system 1, a biological flocculation and sedimentation system 2, and a sediment discharge system 3.

[0039] like Figure 2 As shown, the physical screening system 1 is composed of a collector 101, a filtering device 102 and a lifting device 103. The filtering device 102 is provided with an arc-shaped filtering screen 104 for separating polymetallic nodule sediments. The lifting device 103 is a riser for lifting polymetallic nodules in a deep-sea mining system, which is connected to a mining ship to transport the collected polymetallic nodules to the mining ship.

[0040] like Figure 2 As shown, the biological flocculation sedimentation system 2 is composed of a flocculant storage tank 201, a flocculation tank 202, and a standing tank 203. The flocculant storage tank 201 stores biological flocculants and is connected to the flocculation tank 202 through a delivery pipe 204. The flocculation tank 202 is used to mix sediment and biological flocculants. There are three standing tanks 203, and the three standing tanks 203 work independently. A pumping device 303 is provided on the top of the standing tank, and an openable bottom plate 304 is provided on the bottom.

[0041] like Figure 5 As shown, the sediment discharge system 3 includes a purified seawater discharge system and a sediment solid discharge system. The purified seawater discharge system consists of a pumping device 303 and a drain pipe 305. The pumping device 303 is controlled to discharge the purified seawater to more than 10m below the seabed through the drain pipe 305. The sediment solid discharge system 302 consists of a bottom plate 304 and a discharge pipe 306, which is used to control the bottom plate 304 of the static box and discharge the solid sediment close to the seabed through the sediment discharge pipe 306.

[0042] The arc-shaped filter screen 104 has a diameter of 2 cm and can filter out all the polymetallic nodules and lift them to the mining ship.

[0043] The large particle sediment screening net 105 is used to screen large particle sediments that are insoluble in water and discharge them from the vehicle body through the sediment discharge pipe 306 .

[0044] like Figure 4 As shown, the flocculation box is provided with a stirrer for uniformly mixing the biological flocculant and the sediment, thereby achieving an effective and rapid sedimentation effect.

[0045] The biological flocculant is a new type of flocculant, and its ingredients may contain biological protein, microbial flora, animal and plant extracts, etc. The biological flocculant can inhibit sediment expansion, improve sediment settling properties, and will not cause further chemical pollution to the environment.

[0046] The standing box contains a mixture of sediment and biological flocculant, which is evenly mixed by a stirrer in the flocculation box. The standing box 203 has three working states: water delivery, standing, and discharge, and the three standing boxes 203 are respectively in three different working states: water delivery, standing, and discharge.

[0047] The purified seawater discharge system 301 is responsible for controlling the pumping device 303. When the static tank 203 is in the discharge state, the purified seawater discharge system 301 controls the pumping device 303 to extract 90% of the volume of the purified seawater in the static tank 203 and discharges it to the sea area more than 10m away from the seabed through the drain pipe 305, and controls the drainage speed according to the collection speed.

[0048] The sediment solid discharge system 302 is to control the bottom plate 304 of the still box to open after the still box 203 is drained, so that the sediment is discharged from the sediment discharge pipe 306 at the bottom of the mining vehicle close to the seabed.

[0049] A method for suppressing sediment discharge plume from a seabed mining vehicle is implemented by using the sediment discharge plume suppression device for a seabed mining vehicle according to the present invention. The method comprises the following steps:

[0050] Step 1: When the mining vehicle is mining through the collector, the polymetallic nodules and sediments are collected into the mining vehicle at the same time. The polymetallic nodules and sediments first enter the physical screening system 1 and are screened in the filtering device 102 through an arc-shaped filter screen 104 with a diameter of about 2 cm;

[0051] Step 2: The polymetallic nodules are filtered out and enter the lifting device 103, and are lifted to the mining ship by the riser, while the sediments pass through the arc filter 104 and enter the biological flocculation sedimentation system 2;

[0052] Step 3: The biological flocculant enters the flocculation tank 202 from the flocculant storage tank 201 and mixes with the sediment. The agitator 205 in the flocculation tank 202 rotates to fully mix the biological flocculant and the sediment.

[0053] Step 4: The three static boxes 203 are respectively in three different working states: water delivery, static state, and discharge. The biological flocculant and sediment mixture first flows into the static box 203-1. When the static box 203-1 is full, it will change from the water delivery state to the static state, and the biological flocculant and sediment mixture will flow into the static box 203-2.

[0054] Step 5: When the static tank 203-2 is full, it will change from the water delivery state to the static state, the bioflocculant and sediment mixture will flow into the static tank 203-3, and the static tank 203-1 will change from the static state to the discharge state. The three static tanks 203 operate in this order;

[0055] Step 6: The purified seawater discharge system of the sediment discharge system 3 is responsible for controlling the pumping device 303 to extract 90% of the volume of the purified seawater in the static tank 203-1, and discharge it to the sea area more than 10m away from the seabed through the drainage pipe 305, and control the drainage speed according to the collection speed;

[0056] Step 7: The sediment solid discharge system of the sediment discharge system 3 is to control the bottom plate 304 of the still box 203 to open after the drainage is completed, and discharge the sediment from the sediment discharge pipe 306 at the bottom of the mining vehicle close to the seabed.

Claims

1. A sediment discharge plume suppression device for a seabed mining vehicle, characterized in that: include: Physical screening system, biological flocculation and sedimentation system, sediment discharge system; The physical screening system is composed of a collector, a filtering device and a lifting device. The filtering device is provided with an arc-shaped filtering screen and a large-particle sediment screening screen. The arc-shaped filtering screen is used to separate polymetallic nodules, and the large-particle sediment screening screen is used to screen out sediments with larger diameters. The lifting device is a riser used to lift polymetallic nodules in a deep-sea mining system, which is connected to a mining ship to transport the collected polymetallic nodules to the mining ship. The biological flocculation sedimentation system is composed of a flocculant storage box, a flocculation box, and a static box. The flocculant storage box stores biological flocculants and is connected to the flocculation box through a delivery pipe. The flocculation box is used to mix sediments and biological flocculants. There are three static boxes, which work independently. A pumping device is provided on the top of the static box, and the bottom is an openable bottom plate. The sediment discharge system includes a purified seawater discharge system and a sediment solid discharge system. The purified seawater discharge system consists of a pumping device and a drainage pipe. The pumping device is controlled to discharge the purified seawater through the drainage pipe to more than 10m below the seabed. The sediment solid discharge system consists of a bottom plate and a sediment discharge pipe, which is used to control the bottom plate of the static box and discharge solid sediments close to the seabed through the sediment discharge pipe.

2. A sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: The diameter of the curved filter is less than 2cm, which can filter out all the polymetallic nodules and lift them to the mining ship.

3. The sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: The large particle sediment screening net is used to screen the large particle sediment that is insoluble in water and remove it from the vehicle body through the sediment discharge pipe.

4. The sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: A stirrer is provided in the flocculation box to mix the biological flocculant and sediment evenly, so as to achieve an effective and rapid sedimentation effect.

5. The sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: Bioflocculant is a new type of flocculant, whose ingredients include biological protein, microbial flora, animal and plant extracts. The bioflocculant can inhibit sediment expansion, improve sediment settling properties, and will not cause further chemical pollution to the environment.

6. The sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: The still box contains a mixture of sediment and biological flocculant, which is evenly mixed by a stirrer in the flocculation box. The still box has three working states: water delivery, standing, and discharge, and the three still boxes are respectively in three different working states: water delivery, standing, and discharge.

7. The sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: The purified seawater discharge system is responsible for controlling the pumping device. When the static tank is in the discharge state, the purified seawater discharge system controls the pumping device to extract 90% of the volume of purified seawater in the static tank and discharge it to more than 10m below the seabed, and controls the drainage speed according to the collection speed.

8. The sediment discharge plume suppression device for a seabed mining vehicle according to claim 1, characterized in that: The sediment solid discharge system is to control the bottom plate of the still box to open after the still box is drained, and discharge the sediment from the sediment discharge pipe at the bottom of the mining vehicle close to the seabed.

9. A method for suppressing sediment discharge plume from a seabed mining vehicle, characterized in that: The device for suppressing sediment discharge plume of a seabed mining vehicle according to any one of claims 1 to 8 comprises the following steps: Step 1: When the mining vehicle is mining through the collector, the polymetallic nodules and sediments are collected into the mining vehicle at the same time. The polymetallic nodules and sediments first enter the physical screening system and are screened in the filtering device through an arc filter with a diameter of about 2 cm; Step 2: The polymetallic nodules are filtered out and enter the lifting device, where they are lifted to the mining ship by the riser, while the sediments pass through the curved filter screen and enter the bioflocculation sedimentation system; Step 3: The bioflocculant enters the flocculation tank from the flocculant storage tank and mixes with the sediment. The agitator in the flocculation tank rotates to fully mix the bioflocculant and the sediment. Step 4: The three static tanks are respectively in three different working states: water delivery, static, and discharge. The mixture of bioflocculant and sediment first flows into static tank 1. When static tank 1 is full, it will change from the water delivery state to the static state, and the mixture of bioflocculant and sediment will flow into static tank 2. Step 5: When the static tank 2 is full, it will change from the water delivery state to the static state, the bioflocculant and sediment mixture will flow into the static tank 3, and the static tank 1 will change from the static state to the discharge state. The three static tanks operate in this order; Step 6: The purified seawater discharge system of the sediment discharge system is responsible for controlling the pumping device to extract 90% of the volume of purified seawater in the static tank in the discharge state, and discharge it to the sea area more than 10m from the seabed through the drainage pipe, and control the drainage speed according to the collection speed; Step 7: After the drainage of the settling box is completed, the bottom plate of the settling box is controlled to open, and the sediment is discharged from the sediment discharge pipe at the bottom of the mining vehicle close to the seabed.

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