JPWO2015190280A1 - Air lift pump and underwater sediment suction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air lift pump capable of efficiently sucking underwater deposits. SOLUTION: A main pipe (10) and a working pipe (20) installed in an upright state in water, and by introducing a working fluid from the working pipe (20) to the main pipe (10), the main pipe (10) An air lift pump (1) for sucking deposits together with water from a suction port (12) formed in the lower part and transporting the deposits upward, and a working pipe (20) Heat-insulating part (22) that guides downward in a state of being insulated from the water, and a heat exchanging part that heats and vaporizes the working fluid that has passed through the heat-insulating part (22) by heat exchange with external water and supplies it to the main pipe (10) (24).

Description

  The present invention relates to an air lift pump and a method for sucking underwater deposits.

  As a conventional apparatus for pushing up a liquid, a configuration using an air lift effect by a phase change of a low boiling point working fluid such as Freon is known. For example, Patent Document 1 discloses a liquid booster that injects bubbles of a working fluid from the lower part of a riser pipe through an injection nozzle and raises the inside of the riser pipe with warm water. The air bubbles in the working fluid are separated from the hot water by the gas-liquid separation drum installed at the top of the riser, then condensed and liquefied by the air-cooled condenser, lowered by the dead weight in the downcomer, and again introduced into the lower part of the riser. When heated, it is heated by hot water in the riser tube to form boiling bubbles.

  Patent Document 2 discloses a deep bottom resource suction device in which an air lift pipe is installed in the sea and sucks seabed minerals and the like together with seawater. Undersea resources such as rare earths and manganese nodules are extremely important domestic resources that are essential for the stable supply of resources in Japan, and their development and use are expected. As a pumping system from the seabed, a pump type and a bucket type are known in addition to the air lift type, but the air lift type is promising in terms of achieving both productivity and maintainability.

Japanese Patent Laid-Open No. 1-155099 JP 2000-227100 A

  However, when the liquid lifting device disclosed in Patent Document 1 is used in water such as underwater for collecting seabed resources, there are the following problems. In other words, this liquid push-up device is configured to cause a phase change of the working fluid by utilizing the temperature difference between the hot water temperature in the riser pipe and the ambient temperature of the downfall pipe. When used in a situation where a sufficient temperature difference does not occur between the inside and outside of the pipe, the desired phase change does not occur in the working fluid, and it is difficult to continuously operate.

  In addition, this liquid push-up device is configured so that the working fluid is injected into the riser in the liquid phase and heated in the riser to become a gas phase, so that a phase change of the working fluid occurs. It is necessary to provide this mechanism inside the riser tube, which not only makes the configuration of the phase change portion complicated, but also may cause problems such as damage to the phase change portion due to sucked earth and sand.

  For this reason, the conventional air lift type pumping system requires a power source for introducing the working fluid into the pipe, such as the pressure feed pump disclosed in Patent Document 2 above. Since the load increases as the injection depth increases, development of a pump system that realizes energy saving at low cost has been demanded.

  Therefore, an object of the present invention is to provide an air lift pump and a method for sucking underwater deposits that can efficiently suck underwater deposits.

  The object of the present invention is to have a main pipe and a working pipe installed in an upright state in water, and deposit from a suction port formed in a lower portion of the main pipe by introducing a working fluid from the working pipe to the main pipe. An air lift pump that sucks an object together with water and conveys it upwards, wherein the working pipe guides the supplied liquid-phase working fluid downward in a state insulated from outside water, and the heat insulation This is achieved by an air lift pump including a heat exchanging unit that heats and vaporizes the working fluid that has passed through the unit by heat exchange with external water and supplies the heat to the main pipe.

  In this air lift pump, it is preferable that the heat exchanging portion guides the working fluid upward from the heat insulating portion toward the main pipe.

  A gas-liquid separator that recovers the gas-phase working fluid rising up the main pipe; a compressor that compresses and heats the recovered working fluid; and the working fluid from the compressor that is installed in water It is preferable to further include a heat dissipating part that exchanges heat and cools, and an expander that expands and liquefies the working fluid that has passed through the heat dissipating part, and introduces the liquid working fluid that has passed through the expander into the working pipe. Alternatively, it may further comprise a gas-liquid separator that recovers the gas-phase working fluid that rises in the main pipe, and a cooler that cools and collects the recovered working fluid. It is also possible to introduce a working fluid into the working tube.

  Further, the object of the present invention is to install a main pipe and a working pipe in an upright state in water, and introduce a working fluid from the working pipe into the main pipe, thereby depositing from a suction port formed at a lower portion of the main pipe. A method for sucking a submerged sediment transported upward together with water, wherein the liquid-phase working fluid supplied to the working pipe is guided downward in a heat-insulated state with external water; and The liquid phase working fluid guided below the working pipe is heated and vaporized by heat exchange with external water, and is supplied to the main pipe.

  According to the present invention, it is possible to provide an air lift pump and an underwater deposit suction method that can efficiently suck in underwater deposits.

It is a schematic block diagram of the air lift pump which concerns on one Embodiment of this invention. It is a schematic block diagram of the air lift pump which concerns on other embodiment of this invention. It is a schematic block diagram of the air lift pump which concerns on one Example of this invention. It is a schematic block diagram of the air lift pump which concerns on the other Example of this invention. It is a figure which shows an example of the measurement data of the air lift pump shown in FIG. 4, (a) has shown the flow volume change of the working fluid, (b) has each shown the temperature change of the working fluid. It is a figure which shows the measurement result of the pumping characteristic of the air lift pump shown in FIG. 4, (a)-(c) compares the internal diameter of the main pipe with each other, and compares with the prior art. It is the figure which compared the measurement result shown in FIG. 6 with the numerical calculation result.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an air lift pump according to an embodiment of the present invention. As shown in FIG. 1, the air lift pump 1 includes a main pipe 10 and a working pipe 20 that are installed in a standing state in water such as seawater by a support member (not shown). Unlike the liquid flow device in the closed loop disclosed in Patent Document 1, the air lift pump 1 of this embodiment has versatility that can be used in an open space.

  The main pipe 10 has a suction port 12 formed at the lower end side and a discharge port 14 formed at the upper end side, and the suction port 12 is located in the vicinity of the bottom surface such as the seabed, so that water such as seabed minerals, earth and sand, sludge, etc. The deposit is arranged so as to be sucked from the suction port 12. The discharge port 14 is located above the water surface such as the sea surface, and the underwater sediment sucked together with the water such as seawater from the suction port 12 is discharged from the discharge port 14 and collected by the collection unit 30. The standing state of the main pipe 10 is preferably an upright state, but may be an inclined state.

  The working tube 20 has a lower end side connection port 22 connected above the suction port 12 of the main tube 10. An introduction port 24 is formed on the upper end side of the working tube 20, and a liquid working fluid is introduced into the working tube 20 from the introduction port 24. In addition, the working tube 20 includes a heat insulating portion 26 and a heat exchanging portion 28, the heat insulating portion 26 is disposed on the introduction port 24 side, and the heat exchanging portion 28 is disposed on the connection port 22 side. The standing state of the working tube 20 may be not only an upright state but also an inclined state.

  The heat insulating part 26 guides the working fluid passing through the inside downward while being insulated from the external water. Although the specific structure of the heat insulation part 26 is not specifically limited, For example, the structure which coat | covered the outer peripheral surface of piping which a working fluid passes with water-resistant heat insulating materials, such as a urethane foam and a polyimide, An inner pipe interior using a double pipe The structure etc. which carry out the vacuum insulation of the working fluid of this and the water outside an outer tube | pipe can be mentioned.

  The heat exchange unit 28 heats and vaporizes the working fluid passing through the inside by heat exchange with external water, and supplies the working fluid to the main pipe 10. The heat exchanging portion 28 can be composed of a metal tube having excellent thermal conductivity such as an aluminum alloy, for example, and may be appropriately curved in order to secure a heat transfer area necessary for vaporizing the working fluid. When the heat insulating part 26 is configured by covering the pipe with a heat insulating material or the like, a part of the pipe can be exposed to form the heat exchanging part 28. Use a working fluid whose liquid density is equal to or higher than the density of the surrounding liquid phase (for example, seawater), whose boiling point is equal to or lower than the temperature of the surrounding liquid phase, and insoluble or hardly soluble in the surrounding liquid phase. Can do. In addition to these conditions, a working fluid that is nonflammable or flame retardant and harmless to the human body and living organisms can be used more preferably.

  Next, a method for sucking underwater deposits using the air lift pump 1 having the above configuration will be described. A liquid working fluid is supplied to the working tube 20 from the inlet 24. The working fluid to be used is in a liquid phase at the time of introduction, but in water, the working fluid is appropriately changed in consideration of the water temperature and water pressure at the place where the air lift pump 1 is installed so as to be in a gas phase by heat exchange in the heat exchange unit 28. Just choose. When the air lift pump 1 is installed in the sea where the water depth is relatively shallow, it can be appropriately selected from alternative chlorofluorocarbon having a boiling point lower than the sea water temperature around the heat exchange section 28 in the sea, for example, 1,1,1, 3,3-Pentafluoropropane (HFC-245fa, boiling point: 15.3 ° C.) can be used. At the deep sea floor, the boiling point of the working fluid rises due to high water pressure.For example, HFC-23 (boiling point -82 ° C (1 atm), 0 ° C (about 20 atm)) is preferably used as the working fluid. it can. The working fluid may be determined in consideration of the water depth at the blowing position, for example, HFC-22 (boiling point 4 ° C (about 5 atm)), HFC-32 (boiling point 0 ° C (about 7 atm)), HFC- 134a (boiling point 4 ° C. (about 3.5 atm)) or the like can also be used.

  Since the working fluid introduced into the working tube 20 passes through the heat insulating portion 26, heat exchange with external water is interrupted, so that the liquid phase state is maintained. Accordingly, the working fluid descends due to its own weight in the heat insulating portion 26 and is guided to the heat exchanging portion 28. Then, while the working fluid passes through the heat exchanging portion 28, it is heated by heat exchange with external water, and most of the fluid is changed from the liquid phase to the gas phase and supplied to the main pipe 10.

  The working fluid supplied to the main pipe 10 rises as bubbles B in the water. Due to this air lift effect, underwater deposits M such as seabed minerals are sucked together with water from the suction portion 12 of the main pipe 10 and conveyed upward. Thus, the underwater deposit M discharged together with the water from the discharge port 14 of the main pipe 10 can be recovered in the recovery unit 30. The collection unit 30 can be formed in a container shape having a bottom plate made of, for example, a net plate, and can discharge only water from the bottom plate to store only the underwater deposit M. It is preferable that the working fluid is introduced into the main pipe 10 in the vicinity of the suction port 12 as in the present embodiment. For example, even in the vicinity of the center of the main pipe 10, the underwater sediment M is removed from the suction port 12. It is possible to suck.

  According to the air lift pump 1 of the present embodiment, the working tube 20 guides the liquid-phase working fluid downward in a state in which the working fluid in the liquid phase is insulated from the external water, and the working fluid that has passed through the heat-insulating portion 26 to the external water. A heat exchanging unit 28 that is heated and vaporized by heat exchange with the main pipe 10 to be supplied to the main pipe 10, so that by selecting a working fluid having a boiling point lower than the surrounding water temperature, power for lowering the working fluid, The air lift effect by the working fluid can be generated inside the main pipe 10 without requiring power for causing the phase change of the working fluid. Therefore, suction of underwater sediments can be performed efficiently at low cost. For example, suction of marine resources such as rare earths, manganese nodules and methane hydrate, suction of soil and sand in dredging works at port facilities and dams, etc. It can be suitably used for suction of various underwater deposits such as sludge suction in a dam, dam lake, water storage tank, etc.

  In addition, since most of the working fluid is supplied to the main pipe 10 in a gas phase state, even when the working fluid is injected at a deep water depth, the injection energy is reduced and the working fluid is easily and reliably placed in the main pipe 10. Can be supplied to. In addition, since it is not necessary to provide a phase change portion of the working fluid in the main pipe 10 as in the prior art, it is possible to solve the problems of repair and maintenance of the phase change portion, and the fluid flowing in the main pipe 10 contains solids. It can be suitably used also in the case where

  Furthermore, when the boiling point of the working fluid is lower than the ambient water temperature, the working fluid introduced into the main pipe 10 in a gas phase state is not likely to condense on the way up the main pipe 10. Therefore, the air lift effect can be stably generated, and the underwater deposit can be reliably sucked and conveyed.

  The density of the working fluid in the liquid phase supplied to the working tube 20 is preferably larger than the density of water around the working tube 20. By selecting such a working fluid, it is possible to reliably move the liquid-phase working fluid in the working pipe 20 by its own weight immediately after the start of the air lift pump 1 without requiring auxiliary power. Energy can be reduced.

  FIG. 2 is a schematic configuration diagram of an air lift pump according to another embodiment of the present invention. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The air lift pump 1 ′ shown in FIG. 2 is provided with a gas-liquid separator 40 in the upper part of the main pipe 10 in the air lift pump 1 shown in FIG. 1, and a gas outlet 42 of the gas-liquid separator 40 is introduced into the working pipe 20. By connecting to the port 24 via a reflux pipe 50, the working fluid is configured to circulate with a phase change.

  The reflux pipe 50 includes a compressor 52 that heats the vapor-phase working fluid separated by the gas-liquid separator 40 by adiabatic compression, a heat radiating portion 54 that cools the working fluid heated by the compressor 52, and a heat radiating portion 54. And an expander 56 that liquefies the working fluid cooled in step adiabatic expansion, and the working fluid that has passed through the expander 56 is introduced into the working tube 20. The heat dissipating part 54 can be composed of a pipe made of a material having good thermal conductivity, and is installed in water at a temperature lower than the temperature of the working fluid passing through the inside, so that the working fluid exchanges heat with external water. To cool. This water temperature may be approximately the same as the water temperature around the heat exchange section 28 of the working tube 20. For example, when the main pipe 10 and the working pipe 20 are installed in the sea, the heat radiating unit 54 may be installed in the sea.

  According to the air lift pump 1 ′ shown in FIG. 2, the working fluid separated by the gas-liquid separator 40 is collected after the water containing the underwater deposit M is collected from the liquid outlet 44 of the gas-liquid separator 40 by the collecting unit 30. Since the gas phase is changed to the liquid phase by passing through the compressor 52, the heat radiating portion 54, and the expander 56, the working fluid introduced into the working pipe 20 is used as a power source that causes an air lift effect in the main pipe 10. Reusable. That is, the air lift pump 1 ′ can be operated only with the liquefaction energy of the working fluid, and the underwater sediment M can be efficiently sucked at low cost even when the installation site is deep. Further, the above-described liquefaction energy of the working fluid can be reduced by installing the heat dissipating part 54 in water in the same manner as the main pipe 10 and the working pipe 20, and further cost reduction and high efficiency can be achieved.

  The reflux pipe 50 is preferably airtightly connected to the gas-liquid separator 40 and the working tube 20 so as to surely prevent the entry of air, which is a non-condensable gas. It is preferable to provide a discharge mechanism such as a discharge valve so that the air can be easily discharged to the outside of the reflux pipe 50.

  It is preferable that the liquid exchange position of the working fluid is lower than the gas-phase outflow position so that the heat exchange section 28 can guide the working fluid upward from the heat insulation section 26 side toward the main pipe 10. According to this configuration, the working fluid that has become a gas phase in the heat exchange unit 28 can be reliably guided to the main pipe 10, and the working fluid can be injected into the main pipe 10 more easily. Specifically, as shown in FIG. 2, it is preferable that the heat exchanging portion 28 is disposed to be inclined from the heat insulating portion 26 toward the main pipe 10. Or the heat exchange part 28 can also be comprised from the bending piping etc. which have a perpendicular part in part.

  As mentioned above, although embodiment of this invention was explained in full detail, the specific aspect of this invention is not limited to the said embodiment. According to the present invention, it is possible to reduce the cost of raising resources in the deep seabed and to facilitate the use of seabed resources, which can contribute to the stable supply of resources and energy in Japan. Moreover, as a highly efficient suction device, it can be widely applied to uses other than the suction of seabed resources.

  In order to verify the operation and effect of the present invention, an air lift pump 101 having the configuration shown in FIG. 3 was installed in a water tank and tested. In FIG. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  The main tube 10 had an inner diameter of 11 mm and a length of 1000 mm. The heat insulating portion 26 of the working tube 20 was a pipe having an inner diameter of 11 mm and a length of 900 mm, and was insulated from the surroundings by being covered with neoprene sponge. The heat exchanging portion 28 of the working tube 20 is a pipe having an inner diameter of 11 mm and a length of 150 mm, and is arranged so as to incline linearly at an angle of θ = 60 degrees from the heat insulating portion 26 toward the main pipe 10. The working fluid was HFC-245fa, and the liquid L around the air lift pump 101 was 30 ° C. water. The gas-liquid separator 40 and the working tube 20 are connected via a cooler 60 having a Peltier element 62, and the gas-phase working fluid introduced from the gas-liquid separator 40 is liquefied by Peltier cooling, and the working tube 20 to be introduced.

In the air lift pump 101 having the above-described configuration, when the Peltier element 62 is controlled to 0 ° C. with the power of 110 W, the liquid phase working fluid at 14 ° C. is 0.013 L / min (0.017
kg / min), the working fluid is converted into a gas phase in the heat exchanging section 28, and then introduced into the main pipe 10, whereby the surrounding water L is sucked into the main pipe 10 at a suction flow rate of 30 mL / min. s (1.8 L / min).

  When a device having the same configuration as that of the air lift pump 101 shown in FIG. 3 is installed in the deep sea or the like, when the working fluid rises in the main pipe 10, the pressure of the working fluid decreases as the working fluid rises. The temperature drops. Therefore, by suppressing the amount of heat transfer from the outside to the main pipe 10, the working fluid temperature at the outlet of the main pipe 10, that is, the inflow temperature to the cooler 60 can be reduced, and the amount of heat removed at the cooler 60 is reduced. , Can improve efficiency. Although the method for suppressing the amount of heat transfer of the main pipe 10 is not particularly limited, for example, the outer peripheral surface of the main pipe 10 is covered with a water-resistant heat insulating material such as urethane foam or polyimide similarly to the heat insulating portion 26 of the working pipe 20. A configuration in which the main pipe 10 is a double pipe and the inside of the inner pipe and the outside of the outer pipe are thermally insulated by vacuum is exemplified. The amount of heat transfer of the main pipe 10 may be appropriately adjusted according to the water depth or the like so that the seawater passing through the main pipe 10 does not freeze.

  Next, the air lift pump 101 ′ shown in FIG. 4 was installed in the water storage tank 110 to verify the operation. 4, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals. The main tube 10 had an inner diameter of 11 mm and a length of 1000 mm. The liquid L stored in the water storage tank 110 used 30 ± 1 ° C. water, and the pumping height Hd of the main pipe 10 was set to 300 mm. The working fluid was HFC-245fa. The working tube 20 forms the heat insulating portion 26 in the same manner as the configuration of FIG. 3, and for the heat exchanging portion 28, a casing in which both wall surfaces 28a and 28b are formed of an aluminum plate having a thickness of 0.5 mm is arranged in the vertical direction. By making it stand upright, it was comprised so that the heat input amount might be adjusted with the liquid level height in a casing. The distance Li between the suction port 12 of the main tube 10 and the connection port 22 of the working tube 20 was set to 20 mm. The gas-liquid separator 40 is connected to the cooler 60 via the wet flow meter 120 so that the flow rate of the gas-phase working fluid discharged from the gas-liquid separator 40 can be measured. The cooler 60 includes a reserve bag 64 that serves as a buffer when adjusting the flow rate of the working fluid, and the heat absorption amount can be controlled in accordance with the flow rate of the working fluid by adjusting the voltage applied to the Peltier element 62.

  The above-described air lift pump 101 ′ is operated for 500 seconds, the flow rate of the working fluid is measured by the wet flow meter 120, and the temperature of the working fluid in the four temperature measuring portions T1 to T4 shown in FIG. 4 is measured. Is shown in FIG. FIG. 5A shows the flow rate of the working fluid introduced into the cooler 60, and FIG. 5B shows the temperatures of the temperature measuring units T1 to T4 together with the water temperature in the water storage tank 110. . As is clear from FIGS. 5A and 5B, it was confirmed that both the flow rate and temperature were stable.

  Next, in the air lift pump 101 ′ shown in FIG. 4, three types (8 mm, 11 mm, and 16 mm) of main pipes 10 having different inner diameters are prepared, and the flow rate Qg of the working fluid in the gas phase detected by the wet flow meter 120 is prepared for each. The relationship between (ml / s) and the pumping amount Ql (ml / s) of the main pipe 10 was measured. The result is shown in FIG.

  6A, 6B, and 6C correspond to the case where the inner diameter of the main pipe 10 is 8 mm, 11 mm, and 16 mm, respectively, and the water temperature in the water storage tank 110 is 25 ° C., 30 ° C., 35 When the temperature was set to 40 ° C. and 40 ° C., the relationship between Qg and Ql was measured several times. In order to compare this result with the prior art, compressed air was used as the working fluid introduced into the main pipe 10, and the relationship between the above Qg and Ql was measured.

  6 (a) to 6 (c), the pumping characteristics of the air lift pump 101 'according to the present invention showed the same tendency as the pumping characteristics of the air lift pump of the prior art. That is, it was confirmed that the existing knowledge about the pumping characteristics can be used for the phase change air lift pump of the present invention. As a method for predicting the pumped amount of a conventional air lift pump, there is known a method of numerical calculation using the “one-dimensional two-fluid drift flux model” by Hiyama et al. (1989). The numerical calculation result is shown in FIG. When compared with the measurement results of (a) to (c), it was confirmed that the two values were almost the same as shown in FIG.

1, 1 'Airlift pump 10 Main pipe 12 Suction port 20 Working pipe 26 Heat insulation part 28 Heat exchange part 30 Recovery part 40 Gas-liquid separator 52 Compressor 54 Heat radiation part 56 Expander 60 Cooler

Claims (5)

A main pipe and a working pipe installed in an upright state in water; by introducing a working fluid from the working pipe to the main pipe, the sediment is sucked together with water from a suction port formed in a lower portion of the main pipe; An air lift pump for conveying upward,
The working pipe is configured to heat and vaporize the working fluid that has passed through the heat insulating portion by heat exchange with external water, and a heat insulating portion that guides the supplied liquid phase working fluid downward while being insulated from the external water. An air lift pump comprising: a heat exchanging unit that supplies the main pipe.   The air lift pump according to claim 1, wherein the heat exchange unit guides the working fluid upward from the heat insulating unit toward the main pipe. A gas-liquid separator that recovers the gas-phase working fluid rising up the main pipe;
A compressor that compresses and heats the recovered working fluid;
A heat dissipating unit that is installed in water and cools the working fluid from the compressor by exchanging heat with external water;
An expander that expands and liquefies the working fluid that has passed through the heat dissipation section;
The air lift pump according to claim 1, wherein a liquid-phase working fluid that has passed through the expander is introduced into the working pipe. A gas-liquid separator that recovers the gas-phase working fluid rising up the main pipe;
A cooler that cools and liquefies the recovered working fluid;
The air lift pump according to claim 1, wherein a liquid-phase working fluid that has passed through the cooler is introduced into the working pipe. The main pipe and the working pipe are installed standing in water, and the working fluid is introduced from the working pipe into the main pipe, thereby sucking the deposit together with water from the suction port formed in the lower part of the main pipe, A method for sucking underwater sediment to be conveyed,
Guiding the liquid-phase working fluid supplied to the working pipe downward in a heat-insulated state with external water;
A method of sucking underwater sediment, comprising: heating and vaporizing a liquid-phase working fluid guided below the working pipe by heat exchange with external water and supplying the liquid to the main pipe.