JP5204055B2 - Residue collection system - Google Patents

Description

The present invention is a storage tank for storing various liquids including liquefied gas such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), or a liquid (liquefied gas etc.) disposed in the storage tank. is present in the barrel that houses a pump for paying out, it relates to a system for recovering the residue (foreign matter).

  LNG (liquefied natural gas) stored in the LNG storage tank is in a gas-liquid equilibrium state at normal pressure and -162 ° C. BOG (boil-off gas) is generated by the action of heat and the like, filling the tank.

  By the way, the delivery mechanism of LNG from the LNG storage tank can be roughly divided into two types, one of which is a discharge pump installed outside the storage tank from the viewpoint of ease of maintenance and the like. Thus, the liquefied gas in the storage tank is discharged, and can be generally referred to as an out-tank type discharge mechanism.

  On the other hand, another mechanism is that a barrel having a foot valve for sucking liquefied gas in the storage tank is accommodated in the storage tank, and a discharge pump is accommodated in the bottom of the barrel. With this power, the liquefied gas sucked into the barrel through a foot valve or the like is discharged out of the storage tank through the discharge line, and can be generally called an in-tank type discharge mechanism.

  In this in-tank type dispensing mechanism, a plurality of barrels and a pump accommodated therein are provided in the storage tank, and the number of used radix can be adjusted as appropriate according to the amount of liquefied gas to be dispensed. In this case, even if any pump fails, LNG can be continuously paid out by operating other pumps. In addition, the structure by which such a barrel (pump barrel) was accommodated in the storage tank is disclosed by patent document 1. FIG.

  In any of the above-described payout mechanisms, in order to reuse the BOG generated in the storage tank, a BOG payout line separate from the LNG payout line is provided, for example, both lines are heated. BOG is liquefied in the heat exchanger with the cold heat of LNG (re-liquefaction) through the exchanger, further boosted, merged into the LNG discharge line, sent to the vaporizer, and LNG is vaporized via the vaporizer Thus, a LNG (liquefied gas) payout system is configured to produce city gas.

  Currently, the LNG payout system having the above-mentioned in-tank payout mechanism is being constructed worldwide, and how it copes with various failures that may occur in the system as it becomes more widespread. Whether it can be done is being studied by various companies such as gas-related companies.

  Regarding this failure, as one of them, the present inventors pay attention to a failure in which a part of the dispensing pump accommodated in the barrel is broken and this blocks a foot valve or the like provided in the barrel, The idea of the system and method which can collect | recover such a broken piece etc. of a pump efficiently has been reached. In addition to the broken pieces of this pump, foreign matter that was present in the storage tank of the LNG carrier ship is sent into the LNG storage tank on the ground together with LNG, which closes the foot valve etc. of the barrel of the storage tank. It is also possible to do it. Thus, this invention makes the collection | recovery object the whole of residue (foreign material, residue) other than the liquefied gas which exists in a storage tank.

  It should be noted here that there is no technology that can efficiently recover the residue in the storage tank even when turning to the conventional open technology.

JP-A-6-137495

The present invention has been made in view of the above-described problems, and efficiently removes a liquid contained in a storage tank (including the inside barrel), for example, a residue present in a liquefied gas such as LNG or LPG. It is an object of the present invention to provide a residue collection system that can be collected automatically.

  In order to achieve the above object, a residue collection system according to the present invention is disposed in a storage tank in which a liquid is stored, and is installed in a barrel in which a sealing posture and a sealing release posture can be selected, and in the barrel. Providing a gas into a collection device for collecting residues in the storage tank or the barrel, and a barrel in fluid communication with the liquid in the storage tank, and pressurizing the barrel It has at least a gas control mechanism that executes control for sending the liquid inside the barrel and control for stopping the provision of gas and introducing the liquid into the barrel in the sealing release posture.

  Residues to be collected by the collection system of the present invention include, as described above, residues (damaged pieces) in which the pump is broken, and foreign substances existing in the LNG carrier ship entering the storage tank. In addition, it is intended for any foreign matter present in the tank that stores any liquid, and further, the residue floating in the liquid (or liquefied gas) of the storage tank, the bottom of the storage tank It refers to all other than the liquid (or liquefied gas) that should be originally stored, such as the deposited residue, the residue remaining in the barrel. In addition, “liquid” here refers to all liquids such as water and oil, and “liquefied gas” contained in the liquid refers to LNG, LPG, liquefied nitrogen, liquefied hydrogen, and the like. Is.

  Further, the barrel disposed in the storage tank is prevented from shaking by an appropriate locking member whose upper end is suspended from the roof of the storage tank and whose side surface protrudes inward from the side surface of the storage tank. The stable posture in the storage tank is maintained. In addition, the number of barrels to be arranged may be one or plural, but at least a sealing posture and a sealing release posture can be selected, and a discharge pump is provided in a part of the barrel. There are various cardinal numbers and modes of use, such as what is accommodated and all of which accommodates a dispensing pump.

  Here, the “sealing posture” means that the bottom opening of the barrel is closed with the liquid in fluid communication with the liquid outside the barrel, and the top opening of the barrel is a suitable closing lid made of wood or metal. It means a state where it is blocked by etc. On the other hand, the “sealing release posture” means a state in which the bottom opening of the barrel is similarly closed with liquid, but the top opening is released. That is, when the barrel is in the “sealing posture”, the pressure fluid is provided in the barrel, the liquid in the barrel is pushed down by the pressure of the pressure fluid, and the barrel is filled with the pressure fluid. Can be formed. Note that this “sealing posture” and “sealing release posture” can be changed not only by manual installation by an operator but also by removing the closing lid, as well as via a servo motor or the like. In some cases, the opening / closing posture change is automatically controlled according to an external command from an administrator.

  Then, with the gas control mechanism constituting the recovery system of the present invention, for example, nitrogen gas, which is one of the pressure fluids described above, or BOG (liquid (In the case of LNG) etc. in the barrel, the liquid level of the liquid existing at the same level as the liquid outside the barrel (in the storage tank) in the barrel at the normal time is changed by the pressure of the supplied gas. It can be lowered down. Next, the supply of the gas into the barrel is stopped, and the barrel is set to the “sealing release posture”, whereby the liquid is introduced into the barrel from the outside due to the differential pressure of the liquid inside and outside the barrel.

  During the introduction of the liquid into the barrel, the residues present below the barrel or in the storage tank outside the barrel are introduced into the barrel along with the liquid.

  Here, the above-described recovery device is disposed, for example, below the barrel, and the residue introduced into the barrel is efficiently recovered in the recovery device along with the flow velocity of the liquid introduced at the same time. It will be.

  As one embodiment of the gas providing means constituting this gas control mechanism, it is composed of a utility pressure pipe and a vaporizer existing in the LNG factory (a form in which an existing facility is used as it is. ) And a form in which low-temperature nitrogen is vaporized by a vaporizer and vaporized pressure nitrogen gas is supplied into the barrel at a desired timing (a gas providing means unique to this system). As yet another form, a form in which a pressure gas is generated by a booster pump, a compressor, or the like and this is provided in the barrel may be used.

  As described above, the residue collection system according to the present invention makes effective use of a conventional general barrel disposed in a liquid storage tank, and arranges a collection device therein to generate a flow rate in the liquid in the barrel. The flow rate is used to recover the residue with the recovery device. The operation of the system does not require any skill, and the manufacturing cost of the entire system is also expensive. Don't be.

  When actually operating this system, the dispensing pump accommodated in the barrel is taken out from the barrel, and then the collecting device is disposed at the bottom of the barrel, for example, and then the gas control mechanism is used to move the barrel into and out of the barrel. Liquid entry / exit control is executed. In addition, the timing of collecting the residue is arbitrary, and maintenance may be performed once a year by operating the collection system. For example, when the barrel is abnormally vibrating, a part of the residue may be collected. The system may be determined to be clogged and the system may be activated at that time.

  As one embodiment of the residue collection system, the barrel has a seat portion on which the collection device is seated and a foot valve that allows the liquid to enter and exit from the barrel at a lower position. The recovery device includes a seating body that is seated on the seating portion so as to form a close contact with the seating portion, a standing hole on the seating body, and a first hole in a part of the seating body. A main box having an end opening on the seat body and on the inner side of the main box, and having an end opening in fluid communication with the foot valve at one end thereof; And a secondary box having at least the above-mentioned structure.

  In this embodiment, the sub-box described above further has a lid that can be opened and closed at the other end, and the lid closes when gas is provided in the barrel by the gas control mechanism described above. And an open posture when gas supply into the barrel is stopped may be used. This posture change is closed when pressure fluid is provided in the barrel and the liquid level of the liquid inside is lowered, and the liquid in the storage tank is introduced from the bottom of the barrel to the top of the barrel. When the liquefied gas flows, it means an extremely simple posture change in which the lid opens upward by the fluid pressure, and there is no need to provide a special mechanism for changing the opening / closing posture of the lid.

  In addition, in the seated portion provided in the barrel, the recovery device is desired by itself so that the recovery device always ensures a stable posture in a stable posture during the series of operation of the gas control mechanism. It is good that it is a weight body. In addition, the form which added the weight for increasing the mass to a collection | recovery apparatus is also applicable.

  Also, either the recovery device or the barrel is provided with an engagement member, and when the recovery device comes into close contact with the seated portion of the barrel, the engagement member mechanically engages with a part of the recovery device. The contact posture between the recovery device and the seated portion may be ensured. Thus, in the form in which the lifting of the collecting device is suppressed by the engaging member (hook member), it is not always necessary to consider the weight of the collecting device.

  Further, one or both of the first hole and the second hole described above may be formed from a wire mesh, or a wire mesh may be provided on the surface thereof.

  Here, by the gas supply control into the barrel by the gas control mechanism, the liquid existing in the barrel passes through the first hole of the main box, and the second hole and the end opening of the sub box. Through the foot valve to the outside of the barrel, and by the gas supply stop control by the gas control mechanism, the liquid outside the barrel passes through the foot valve, through the end opening, and to the second hole. The residue flows into the barrel through the first hole, and the residue is accommodated in the space defined by the main box, the sub-box, and the seat through the second hole. It may be a form.

  When adjusting the dimensions of the first hole and the second hole or adjusting the opening size of the mesh structure of the above-described wire mesh, for example, regarding the opening size of the wire mesh, it is provided in the second hole of the sub box. Since the wire mesh provided in the first hole of the main box and the wire mesh provided in the first hole has a smaller opening size than the size of the residue, it is carried along the upward flow of liquid. For example, the remaining residue can be accommodated in the space between the main box and the sub-box through the upper opening of the sub-box, and the residue trapped in this space can be accommodated inside the sub-box. And it can be prevented from escaping outside the main box.

  In addition, in the case where the secondary box does not have an upper end opening (a form in which the upper end is completely closed), the wire mesh provided in the second hole of the secondary box is used for the expected residue. By setting the opening size to be larger than the size, the residue can be accommodated in the space between the main box and the sub box through the second hole of the sub box.

  On the other hand, by the gas supply control to the barrel by the gas control mechanism, the liquid existing in the barrel passes through the first hole of the main box and the second hole and the end opening of the sub box. Through the foot valve, and by the gas supply stop control by the gas control mechanism, the liquid outside the barrel passes through the foot valve, through the end opening, and the second hole and It flows into the barrel through an opening formed by opening the first hole and the lid, and is defined by the main box, the sub-box, and the seating section through the opening formed by opening the lid. The form which the said residue is accommodated in the made space may be sufficient.

  In this embodiment, the lid provided on the sub-box is mainly opened, and the residue is collected between the sub-box and the main box. The lid can be easily opened by the flow velocity pressure of the flowing liquid, and the upper end opening of the secondary box has a relatively large size, so that the upper end opening is not affected by the size of the residue. Thus, the residue can be effectively captured in the recovery device.

  Note that the seating body, main box, sub-box, lid, etc. that make up the recovery device described above are all easy to process, including welding, etc., and ensure a stable posture in the series of operation processes of the gas control mechanism. From the viewpoint of (that is, having a desired weight), etc., it is preferably formed from stainless steel, but in addition, it may be formed from an appropriate metal material or a resin material containing ceramics. .

  The residue collecting method according to the present invention is a residue collecting method for collecting residues in a storage tank in which a liquid is stored or in a barrel disposed in the storage tank, A first step of taking out a liquid discharge pump disposed in the barrel from the barrel, a recovery device for recovering the residue in the barrel is placed, and the barrel is kept in a sealed posture and stored. A second step of providing gas into a barrel in fluid communication with the liquid in the tank to pressurize the barrel and pumping the liquid in the barrel out of the barrel, stopping the supply of gas into the barrel; And at least a third step of introducing a liquid outside the barrel into the barrel and collecting the residue with the collecting device when the liquid is introduced. You Than is.

  Similar to the residue collection system of the present invention described above, by applying this residue collection method, it is possible to effectively remove residue that has accumulated or floated in the storage tank outside the barrel or outside the barrel. It can be recovered by a recovery device.

  Moreover, in this recovery method, since the pressure fluid such as nitrogen gas is provided in the barrel, and then the gas supply is stopped and the liquid is introduced into the barrel, any skill can be obtained. Further, no advanced control is required, and the residue can be collected in a short time, and maintenance in the barrel and storage tank can be performed. Also in this residue recovery method, the liquid stored in the storage tank refers to all liquids such as water, oil, and liquefied gas, and this “liquefied gas” includes LNG, LPG. , Liquefied nitrogen, liquefied hydrogen, and the like.

As can be understood from the above description , according to the residue collection system according to the present invention, a generally used barrel for housing a dispensing pump is used effectively to allow liquid to enter and exit from the inside. When the liquid is introduced into the barrel, the residue is simultaneously taken into the barrel, and further, the residue taken in by the collecting device arranged in the barrel is captured, so the system configuration is simple, The production cost is also low, and the method does not require high control. Therefore, it can be a part of extremely effective maintenance technology for the LNG dispensing system having an in-tank type dispensing mechanism whose construction is spreading worldwide.

It is the schematic diagram explaining the residue collection | recovery system of this invention. It is the schematic diagram explaining the condition in the barrel before a residue collection system was formed. It is the longitudinal cross-sectional view explaining the structure of the barrel lower end before a collection | recovery apparatus is arranged. It is the longitudinal cross-sectional view explaining the structure of the barrel lower end after the collection | recovery apparatus was arranged with the structure of one Embodiment of a collection | recovery apparatus. It is a VV arrow line view in FIG. It is the figure explaining other embodiment of the engagement member (engagement mechanism) which engages a collection | recovery apparatus. It is the flowchart explaining the residue collection | recovery method of this invention in order of (a) and (b). FIG. 8 is a flowchart illustrating the residue recovery method of the present invention in the order of (a) and (b) following FIG. 7. FIG. 9 is a flowchart illustrating the residue recovery method of the present invention in the order of (a) and (b) following FIG. 8.

  Hereinafter, embodiments of a residue collection system and a residue collection method of the present invention will be described with reference to the drawings. In addition, although the example of illustration has shown the form with which one barrel was arranged in the storage tank for easy explanation, of course, the number of barrels may be two or more. is there. Moreover, although the liquefied gas is accommodated in the illustrated storage tank, it is needless to say that the liquid accommodated in the storage tank is not limited to the liquefied gas.

  FIG. 1 is a schematic diagram illustrating a residue collection system according to the present invention, and shows a configuration aspect when collecting a residue. The residue recovery system 100 includes a storage tank 1 in which a liquefied gas (for example, LNG) is stored and filled with a boil-off gas BOG, and an upper end of the storage tank 1 that is stored in the storage tank 1 from the roof to the outside. A barrel 2 that protrudes and is suspended from the roof by a suspension member 12 made of mold steel, etc., a recovery device 5 disposed at the lower end of the barrel 2, a pressure pipe 32 that communicates with the barrel 2, and a communication with the pressure pipe 32 The carburetor 31 and the gas control mechanism 3 including the control computer 33 that activates the carburetor 31 to generate pressure fluid at a desired timing and stops the generation thereof. Here, with respect to the control computer 33, since the controller controls the adjustment of the pressure gas amount, the supply of the pressure gas into the barrel and the stop thereof, the administrator manages the pressure sensor for sensing the pressure in the barrel. However, this is not always necessary when providing or stopping the pressure gas.

  Note that FIG. 2 illustrates a configuration mode when paying out general LNG or the like. A payout pump P is arranged at the lower end of the barrel 2, and a payout line L 1 leading to the payout pump P or the barrel 2. For example, LNG is discharged to a heat exchanger (not shown), and the LNG that has passed through the heat exchanger is further sent to a vaporizer (not shown) to provide gas to consumers. In the illustrated example, the pressure pipe 32 is in the middle of the payout line L1 leading to the barrel 2, and when the pressure gas is supplied from the pressure pipe 32 into the barrel 2, the valve v2 on the pressure pipe 32 side is opened. The valve v1 on the discharge line L1 side is controlled to be closed, and the reverse control is executed when the normal liquefied gas is discharged.

  In addition, LPG from a separate storage tank (not shown) is provided to the LNG on the upstream side or the downstream side of the vaporizer, and the gas is supplied to the consumer after the heat amount adjustment of the LNG is performed. Alternatively, the system of the present invention shown in FIG. 1 may be formed in a storage tank for LPG for adjusting the amount of heat.

  On the other hand, the BOG filled in the storage tank 1 is discharged to a heat exchanger (not shown) via a separate discharge line L2, and is liquefied by receiving the cold heat of LNG in the heat exchanger. A liquefied boil-off gas is provided to the LNG. It goes without saying that the LNG facility may not have a mechanism for reliquefying BOG.

  At the time of maintenance for collecting the residue, the upper cover 25 is opened and the discharge pump P is mounted on the roof from the state of the storage tank 1 that provides ordinary LNG to consumers as shown in FIG. It is taken out from the barrel 2 by being wound up by a winder 4, and then the collecting device 5 is suspended in the barrel 2 by using the hoisting device 4, and the collecting device 5 is suspended from the upper lid 25 via a hanging wire 26. 1 is closed, and the upper lid 25 is closed to make the inside of the barrel 2 a sealed space, thereby forming a maintenance posture as shown in FIG.

  Returning to FIG. 1, the barrel 2 has openings at its upper and lower ends. When the residue collection system is operated, the upper end opening is blocked from the outside by the upper lid 25, and the lower end opening is The liquefied gas LG in the storage tank 1 is in fluid communication, and thus the space above the barrel 2 (the space above the liquefied gas in the barrel 2) forms a sealed space.

  Note that the anti-shake material 11 protruding from the side surface of the storage tank 1 to the inside prevents the barrel 2 suspended from the roof via the suspension material 12 and ensures its stable posture.

  Next, with reference to FIGS. 3 to 5, the structure of the barrel lower end and the structure of an embodiment of the recovery device will be described. 3 is a longitudinal sectional view illustrating the structure of the lower end of the barrel before the collection device is arranged, and FIG. 4 is a diagram illustrating the structure of the lower end of the barrel after the arrangement of the collection device. And FIG. 5 is a view taken along arrows VV in FIG. 4.

  As shown in FIG. 3, the barrel 2 has a main body 21 extending from the substantially lower end of the storage tank 1 to the outside of the roof, a leg member 22 joined to the main body 21 by bolts or welding, and a lower part of the leg member 22. The bottom plate 23 is movable up and down with the leg member 22 through a foot valve adjusting mechanism 24 such as a coil spring.

  On the other hand, in the posture placed in the barrel 2, the collecting device 5 is similar to the seat body 53 placed on the bottom plate 23 and the main box body 51 standing on the seat body 53. The auxiliary box 52 is provided on the seating body 53 and is positioned inside the main box 51, and the weight 54 for increasing the overall weight of the recovery device 5. It should be noted that all the constituent members of the recovery device 5 are preferably made of stainless steel in order to obtain processability and a given weight.

  In the mounting posture of the collection device 5, a mortar-shaped bottom surface 53 a formed on the seat body 53 and a seated portion 22 a formed on the leg member 22 of the barrel 2 are in close contact with each other. The leg member 22 is provided with a hook member 27 as shown by a chain line in FIGS. 3 and 4 so as to be rotatable together with a coil spring or the like. When the collecting device 5 is placed on the leg member 22, The hook member 27 may be rotated to mechanically lock the seat 53 and the like of the collection device 5 to prevent the collection device 5 from being lifted. Measures such as increasing the weight are not necessarily required.

  When the collection device 5 is placed, the spring of the foot valve adjusting mechanism 24 constituting the barrel 2 is extended (the bottom plate 23 is lowered downward (descent amount: δ)), and the legs 22 and the bottom plate 23 are An opening is formed in between, and this forms a foot valve FV that enables fluid communication between the barrel 2 and the outer storage tank 1 (opening height: t is about 30 mm, for example). The leg member 22 is provided with a non-rotating material 22b, and the bottom surface 53a is in a non-rotatable state by the non-rotating material 22b in a posture in which the bottom surface 53a of the seating body 53 and the seated portion 22a of the barrel 2 are in close contact with each other. It is designed to be locked with.

  The main box 51 has a cylindrical main body 51 a and a top end metal mesh 51 b (first hole) that forms an upper end opening thereof, and the main body 51 a is suspended by a suspension wire 26. In addition, it can confirm that the collection | recovery apparatus 5 was suspended in the barrel 2, and this was mounted in the predetermined position by performing the length management of the suspension wire 26, and the tension management which acts on the suspension wire 26. .

  On the other hand, the secondary box 52 includes a cylindrical main body 52a, an opening / closing lid 52b whose upper end opening can be opened and closed, a lower opening 52c fluidly communicating with the foot valve FV, and a second hole formed in the main body 52a. 52d.

  On the premise of such a configuration of the recovery device 5, the flow of liquefied gas from the inside of the barrel 2 into the storage tank 1 outside thereof and the reverse flow thereof, that is, the liquefied gas from the inside of the storage tank 1 into the barrel 2 The flow of will be described.

  As will be described later, when a pressure fluid such as nitrogen gas is provided in the barrel 2, the liquid level of the liquefied gas that has been at the same level inside and outside the barrel 2 is lowered, and the liquefied gas that has decreased due to the lowered liquid level is Then, it is discharged out of the barrel 2 via the foot valve FV via the top end wire mesh 51b of the main box 51, the second hole of the sub box 52 and the end opening 52c (indicated by the arrow X1 in FIG. 4). flow). When the liquefied gas flows, the opening / closing lid 52b of the sub box 52 is closed.

  On the other hand, when the liquefied gas in the barrel 2 is completely discharged, for example, when the supply of the pressure fluid is stopped and the liquefied gas outside the barrel 2 is introduced into the barrel 2, the foot valve FV is used, The liquefied gas enters the barrel 2 through the end opening 52c, and the open / close lid 52b of the sub-box 52 is opened by the flow velocity pressure of the rising liquefied gas. Note that the liquefied gas in the barrel 2 does not necessarily have to be entirely discharged to the outside of the barrel 2 due to the provision of the pressure fluid, and a part of the liquefied gas in the barrel 2 is discharged to the outside of the barrel 2. Any level may be used as long as the desired flow velocity of the liquefied gas flowing from the outside of the barrel 2 is achieved by the differential pressure generated.

  The introduced liquefied gas enters the barrel 2 through the open upper opening and the second hole 52d and through the top metal mesh 51b of the main box 51. In this process, the periphery of the foot valve FV, etc. Residue Z deposited in the cylinder 2 rides on the flow of the liquefied gas introduced into the barrel 2 and passes through the end opening 52c and the upper opening of the sub box 52 in which the opening / closing lid 52b is opened. The space is defined by the main box 51, the sub-box 52, and the seat 53.

  Here, by adjusting the opening size forming the net structure of the top end metal mesh 51b and the opening size of the second opening 52d of the sub box 52 to be smaller than the expected size of the residue Z, The residue Z captured in the space defined by the box 51, the sub box 52, and the seating body 53 can be retained in the space.

  Once the liquefied gas enters and exits the barrel 2 once or a plurality of times and the residue Z is recovered by the recovery device 5, the suspension wire 26 is wound up by the hoisting machine 4 on the ceiling of the storage tank 1 and the recovery device By collecting 5, the residue deposited in the storage tank 1 or the barrel 2 can be collected effectively and efficiently.

  As another engagement mechanism for engaging the recovery device 5A not equipped with the weight body in the barrel in a stable posture, as shown in FIG. 6, the recovery device 5A includes a pantograph-type link mechanism 6. It may be a form.

  The link mechanism 6 is driven by various fluid pressures, and a drive mechanism 61 composed of a jack, a servo motor, or the like is driven and controlled from the outside. Is pressed against the main body 21 of the barrel, and the recovery device 5A is engaged in the barrel.

  Next, the residue recovery method of the present invention will be outlined with reference to FIGS. Here, FIGS. 7a and b, FIGS. 8a and b, and FIGS. 9a and b are flowcharts of the collection method in this order.

  First, as shown in FIG. 7a, the upper lid 25 that closes the upper end opening of the barrel 2 protruding from the roof of the storage tank 1 is removed to open the upper end opening, and the roof is opened through the upper end opening. The payout pump P in the barrel 2 is lifted and collected by the hoisting machine 4 mounted on the top (first step).

  Next, as shown in FIG. 7 b, the collection device 5 is suspended in the barrel 2 and installed at the lower end thereof, and the upper lid 25 is installed at the upper end of the barrel 2. In this state, the upper end opening of the barrel 2 is closed, and the lower end is closed with liquefied gas communicating with the outside of the barrel via the foot valve FV. Therefore, the interior of the barrel 2, particularly the space above the liquefied gas, is completely sealed.

  When the inside of the barrel 2 is sealed, as shown in FIG. 8a, the gas control mechanism is operated to supply nitrogen gas, which is a pressure fluid, into the barrel 2 via the pressure pipe 32. This fluid pressure: p Thus, the liquefied gas in the barrel 2 is pushed out of the barrel (X1 direction), and the liquid level is lowered. As shown in FIG. 8b, the supply of pressure gas into the barrel 2 continues until the liquefied gas in the barrel 2 is completely pushed out of the barrel 2, or a desired amount of that portion is pushed out. (Second step).

  When a part or all of the liquefied gas in the barrel 2 is pushed out of the barrel 2, this time, as shown in FIG. 9a, the supply of the pressure gas into the barrel 2 by the gas control mechanism is stopped, and the upper end of the barrel 2 is stopped. The upper lid 25 is released to release the sealing posture of the barrel 2. The upper lid 25 is released by automatic control by an administrator when the upper lid 25 can be opened and closed automatically, and is manually released by an operator.

  When the supply of the pressure gas is stopped and the sealed posture in the barrel 2 is released, the liquefied gas in the storage tank 1 is introduced into the barrel 2 by the differential pressure of the liquefied gas inside and outside the barrel 2 (in the X2 direction in FIG. 9a). In this process, residues that have been deposited and suspended in the storage tank 1 or below the barrel 2 are captured by the recovery device 5.

  The flow up to FIGS. 8 a, b, and 9 a is performed once or twice or more, and when the residue is completely captured, the collection device 5 is collected by the hoisting machine 4.

  When the residue is collected and maintenance is completed, the dispensing pump P is returned to the barrel 2 again, and normal LNG dispensing control (using the dispensing line L1) is executed. As described above, the BOG payout (payout line L2) and its reliquefaction are also performed at the same time.

  By using the residue collection system 100 of the present invention described above or applying the residue collection method, the residue such as the broken pieces of the pump existing in the storage tank 1 or the barrel 2 can be refined. It can be executed effectively without requiring control.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Storage tank, 11 ... Anti-shake material, 12 ... Suspension material, 2 ... Barrel, 21 ... Main body, 22 ... Leg material, 22a ... Seated part, 22b ... Anti-rotation material, 23 ... Bottom plate, 24 ... Foot valve Adjustment mechanism, 25 ... upper lid, 26 ... hanging wire, 3 ... gas control mechanism, 31 ... vaporizer, 32 ... pressure piping, 33 ... control computer, 4 ... hoisting machine, 5 ... recovery device, 51 ... main box, 51a ... Main body, 51b ... Top end wire mesh (first hole), 52 ... Sub-box, 52a ... Main body, 52b ... Opening / closing lid, 52c ... End opening, 52d ... Second hole, 53 ... Seating body, 55 ... Weight: 6 ... Pantograph type link mechanism (engagement member), 100 ... Residue collection system, LG ... Liquefied gas (LNG, LPG), BOG ... Boil-off gas, Z ... Residue

Claims (8)

A barrel that is disposed in a storage tank in which liquid is stored and is capable of selecting a sealing posture and a sealing releasing posture, wherein the bottom opening of the barrel is in fluid communication with the liquid outside the barrel. It is a posture in which the upper opening of the barrel is closed with the liquid, and the sealing release posture is closed with the liquid in a state where the bottom opening of the barrel is in fluid communication with the liquid outside the barrel. A barrel in which the opening is released, and
A recovery device installed in the barrel for recovering residues in the storage tank or the barrel;
The gas is supplied to a barrel in a sealed position and in fluid communication with the liquid in the storage tank, the inside of the barrel is pressurized and the liquid inside the barrel is sent out of the barrel, and the supply of the gas is stopped. a gas control mechanism for executing control, introducing a liquid into the barrel of the sealed releasing posture, the at least Yes,
The barrel has a seated portion on which the recovery device is seated, and a foot valve that allows liquid to enter and exit from the barrel at a position below the barrel.
The recovery device is
A seating body that sits on the seating portion and forms a close contact posture with the seating portion;
A main box which is erected on the seating body and has a first hole in a part thereof;
A sub-box having an end opening on the seating body and inside the main box, having an end opening in fluid communication with the foot valve at one end thereof, and having a second hole on a side surface thereof; At least ,
The secondary box further has a lid that can be opened and closed at the other end,
The lid forms a closed posture when gas is provided in the barrel by the gas control mechanism and an open posture when gas supply into the barrel is stopped. Material collection system. The residue collection system according to claim 1 , wherein the collection device further includes a weight body for increasing its mass. Either the recovery device or the barrel is provided with an engaging member, and when the recovery device is in close contact with the seated portion of the barrel, the recovery device and the seated portion are engaged with the engaging member. The residue collection system according to claim 1 , wherein a close contact posture is ensured. It said first hole, the second hole, either one or both of, and is formed from a wire mesh, or in which wire mesh is provided on their surfaces, claim 1-3 Residue collection system as described in. Due to the gas supply control to the barrel by the gas control mechanism, the liquid existing in the barrel passes through the first hole of the main box and the second hole and the end opening of the sub box. It flows from the foot valve to the outside of the barrel,
By the gas supply stop control by the gas control mechanism, the liquid outside the barrel flows into the barrel through the foot valve, the end opening, the second hole and the first hole. And
The residue collection system according to any one of claims 1 to 4 , wherein the residue is accommodated in a space defined by a main box, a sub-box, and a seating portion through the second hole. . Due to the gas supply control to the barrel by the gas control mechanism, the liquid existing in the barrel passes through the first hole of the main box and the second hole and the end opening of the sub box. It flows from the foot valve to the outside of the barrel,
By the gas supply stop control by the gas control mechanism, the liquefied gas outside the barrel passes through the foot valve, through the end opening, and through the opening in which the second hole, the first hole, and the lid are opened. To flow into the barrel,
The residue according to any one of claims 1 to 4 , wherein the residue is accommodated in a space defined by a main box, a sub-box, and a seat through an opening formed by the lid. Collection system. Wherein the liquid is a liquefied gas, residue recovery system according to any one of claims 1-6. The residue collection system according to claim 7 , wherein the liquefied gas is one of liquefied natural gas (LNG) or liquefied petroleum gas (LPG).

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