JP2004243270A - Driving-gear by hydraulic motor and natural gaseous hydrate generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving-gear by a hydraulic motor which drives a device installed under a pressure higher than the atmospheric pressure, is simple in construction and is low in the cost required for the installation. <P>SOLUTION: A shaft body 41 of an apparatus for expelling water is installed within a casing 100a held under the pressure higher than the atmospheric pressure and the hydraulic motor 100 for driving the shaft body 41 is installed within the casing 100a. Further, an operation oil ought to drive the hydraulic motor 100 is preliminarily pressurized and is kept higher than the atmospheric pressure. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving device for driving a driven machine installed at a pressure higher than the atmospheric pressure.
[0002]
[Prior art]
Currently, as a method of storing and transporting natural gas mainly composed of hydrocarbons such as methane, natural gas is collected from gas fields, cooled to a liquefaction temperature, and stored and liquefied natural gas (LNG). The method of transportation is common. However, in the case of methane, which is a main component of liquefied natural gas, for example, cryogenic conditions require cryogenic conditions such as -162 ° C. In order to perform storage and transport while maintaining such conditions, a dedicated storage device is required. And a dedicated transportation means such as an LNG transport ship. Since the production, maintenance and management of such devices and the like require extremely high costs, low-cost storage and transportation methods as alternatives to the above methods have been intensively studied.
[0003]
As a result of these studies, a method has been discovered in which natural gas is hydrated to produce a hydrate in a solid state (hereinafter referred to as "natural gas hydrate") and stored and transported in this solid state. Particularly promising (for example, Patent Document 1 below). This method does not require cryogenic conditions as in the case of handling LNG, and is relatively easy to handle because it is solid. For this reason, an existing refrigeration system or a slightly improved version of an existing container ship can be used as a storage device or a transportation means, and therefore, it is expected that the cost can be significantly reduced.
[0004]
[Patent Document 1]
JP 2000-264851 A
[0005]
[Problems to be solved by the invention]
By the way, in the hydrate production apparatus described in Patent Document 1, the natural gas hydrate taken out of the production vessel contains a large amount of water, and it is extremely inefficient to transport and store it as it is. Therefore, it is necessary to dehydrate the natural gas hydrate using a dehydrator, but the natural gas hydrate taken out of the production vessel must be maintained at a higher pressure than the gas hydrate production pressure as in the production. Will be disassembled. Therefore, the dehydrator must be placed in a pressurized atmosphere equivalent to that at the time of generation.
[0006]
The problem here is what to do with the drive of the dehydrator. Since this machine handles flammable substances called natural gas hydrate, the use of electric motors that can cause ignition must be avoided as much as possible. Therefore, a hydraulic motor is likely to be used as a usable device. However, to drive a dehydrating device placed inside a housing in a pressurized atmosphere, whether the motor or the hydraulic motor is used, the housing and the drive shaft must be connected. It is necessary to ensure sufficient airtightness between them. This is a condition that must be satisfied in order to ensure safety because the substance to be handled is flammable. In order to satisfy this condition, it is common to install a shaft sealing device between the housing and the drive shaft. However, the shaft sealing device has a complicated structure and is very expensive, and maintenance is troublesome. In addition to this, initial equipment costs increase.
[0007]
The present invention has been made in view of the above circumstances, and drives a device installed at a pressure higher than the atmospheric pressure, and has a simple structure and an inexpensive installation cost, and is driven by a hydraulic motor. The purpose is to provide.
[0008]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, a drive device using a hydraulic motor having the following configuration is employed.
That is, in the driving device using a hydraulic motor according to claim 1 of the present invention, a driven machine is installed inside a housing maintained at a pressure higher than the atmospheric pressure, and the hydraulic motor that drives the driven machine is mounted on the housing. It is characterized by being installed inside the body.
[0009]
In the present invention, the hydraulic motor is installed in the housing of the pressurized atmosphere like the machine to be driven, so that it is not necessary to provide a shaft sealing device, the structure is simplified, and the installation cost is reduced. Can be
[0010]
According to a second aspect of the present invention, there is provided the hydraulic motor drive device according to the first aspect, further comprising a preload means for pre-pressurizing hydraulic oil to drive the hydraulic motor to a pressure higher than the atmospheric pressure. It is characterized by having.
[0011]
When the hydraulic motor is placed in a pressurized atmosphere, in order to drive the hydraulic motor, the pressure obtained by adding the atmospheric pressure to the drive pressure (the pressure to be supplied to drive the hydraulic motor under atmospheric pressure) is applied to the hydraulic motor. Must be supplied. Therefore, in the present invention, by pre-pressurizing the hydraulic oil for driving the hydraulic motor to be higher than the atmospheric pressure, the work to be performed for driving the hydraulic motor is reduced by the preload. This makes it possible to reduce energy consumed for driving the hydraulic motor.
[0012]
According to a third aspect of the present invention, there is provided a hydraulic motor driving apparatus according to the second aspect, wherein a pressure source of the preload means is common to a pressure source for pressurizing the inside of the housing. .
[0013]
In the present invention, by sharing the pressure source of the preload means with the pressure source for pressurizing the inside of the housing, the work to be performed for driving the hydraulic motor is offset by the atmospheric pressure, and the normal drive is performed. It is only necessary to raise the pressure.
[0014]
According to a fourth aspect of the present invention, there is provided a hydraulic motor driving apparatus according to the second or third aspect, further comprising a replenishing means for compensating for a decrease in the operating oil.
[0015]
In the present invention, the hydraulic motor can be continuously driven without running out of the hydraulic oil by compensating for the decrease in the hydraulic oil.
[0016]
The screw press type dewatering apparatus according to claim 5, wherein the container body has an inside maintained at a pressure higher than the atmospheric pressure, and a shaft body having a spiral ridge on a side surface and arranged in the internal space of the container body. A screw press type dehydrator comprising:
The shaft body disposed inside the container body is a driven machine, and a drive device by a hydraulic motor according to any one of claims 1 to 4 is provided to drive the shaft body.
[0017]
In the present invention, since the hydraulic motor is installed in the container in the pressurized atmosphere similarly to the shaft to be driven, there is no need to provide a shaft sealing device, the structure is simplified, and the cost for installing the dewatering device is reduced. Can be reduced inexpensively.
[0018]
The natural gas hydrate generating system according to claim 6 is configured to generate natural gas hydrate by reacting natural gas with raw water in a generating vessel maintained at a pressure higher than atmospheric pressure. A dehydration means for dehydrating natural gas hydrate, comprising a natural gas hydrate generation system,
The dehydrating means includes a container body having an interior maintained at a pressure higher than the atmospheric pressure, and a shaft body having a spiral ridge on a side surface and arranged in an internal space of the container body,
The shaft body disposed inside the container body is a driven machine, and a drive device by a hydraulic motor according to any one of claims 1 to 4 is provided to drive the shaft body.
[0019]
In the present invention, since the hydraulic motor is installed in the container in the pressurized atmosphere similarly to the shaft to be driven, there is no need to provide a shaft sealing device, the structure is simplified, and the cost for installing the dewatering device is reduced. Is reduced, and as a result, the equipment cost of the entire system is reduced.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. In the following, an outline of a natural gas hydrate generation system to which a drive device using a hydraulic motor of the present invention is applied will be described first, and then details of a drive device using a hydraulic motor will be described.
FIG. 1 shows a specific device configuration of a natural gas hydrate generation system that employs a hydraulic motor drive device of the present invention. Hereinafter, in the figure, reference numeral 11 denotes a production reactor for producing natural gas hydrate by reacting natural gas and raw water at a temperature higher than the freezing point and at a pressure higher than the atmospheric pressure, and 12 denotes a produced natural gas hydrate. Is a screw press type dehydrator for physically dehydrating water, and 13 is a twin-screw type dehydrator for producing natural gas hydrate by reacting residual moisture contained in natural gas hydrate with natural gas during or after dehydration. , 14 is a screw conveyor type cooling device for cooling the generated natural gas hydrate, 15 is a valve switching type decompression device for reducing the pressure of the cooled natural gas hydrate to atmospheric pressure, 16 is molding and solidifying the natural gas hydrate. This is a pressing press molding apparatus. Reference numeral 17 denotes a water storage tank for storing water as a raw material, reference numeral 18 denotes a gas field for producing natural gas also for the raw material, and reference numeral 19 denotes a gas storage unit for storing natural gas produced from the gas field 18.
[0021]
The production reaction device 11 has a pressure vessel 20. The pressure vessel 20 is connected to a water pipe 21 for introducing raw water in the water storage tank 17 and a gas pipe 22 for introducing natural gas in the gas storage unit 19. The water pipe 21 is provided with a water pump 23 that sucks up the raw water and introduces the raw water into the pressure vessel 20, and a valve 24. Raw water is introduced into the pressure vessel 20 to form an aqueous phase L, and natural gas is introduced into the pressure vessel 20 to form a gas phase G.
[0022]
Further, the pressure vessel 20 is provided with a pressure gauge 25 for measuring the pressure of the gas phase G, and the gas pipe is provided with a valve 26 and a flow control valve 27. The opening degree of the flow rate control valve 27 is set so that natural gas is replenished inside the pressure vessel 20 based on the measurement value of the pressure gauge 25 to maintain the pressure of the gas phase G at the gas hydrate generation pressure (for example, 5.0 MPa). Controlled.
[0023]
The pressure vessel 20 is provided with a cooling device 28 that keeps the temperature of the aqueous phase L higher than the freezing point and lower than the generation temperature of the gas hydrate (this state is defined as “supercooling”). I have. The reason why the inside of the pressure vessel 20 is kept in a supercooled state by the cooling device 28 is that the heat of hydration generated in the process of generating the natural gas hydrate is recovered, and the inside of the pressure vessel 20 is always kept at the generation temperature (for example, 4. (0 ° C. to 6.0 ° C.).
[0024]
The pressure vessel 20 is connected to a water pipe 30 that connects the bottom and the top to circulate the raw water. In the water pipe 30, a water circulation pump 31 that sucks up and circulates the raw water in the aqueous phase L, a heat exchanger 32 that cools the raw water sucked up by the water circulation pump 31, a filter 33 that transmits only the raw water, Valves 34 and 35 are provided. A spray nozzle 36 for spraying raw water into the gas phase G is provided at the tip of the water pipe 26 projecting inward from the top of the pressure vessel 20.
[0025]
The side wall of the pressure vessel 20 is provided with a slurry outlet 20a for extracting a slurry-like natural gas hydrate generated on the liquid surface of the aqueous phase L, and the pressure vessel 20 is connected to the slurry outlet 20a. The slurry press 37 is connected to the screw press type dehydrator 12 via a slurry pipe 37. The slurry pipe 37 is provided with a valve 38 and a slurry extraction pump 39 for sucking slurry floating on the liquid surface of the aqueous phase L.
[0026]
The screw press type dewatering device 12 includes a container body 40 having a cylindrical internal space 40a, and a shaft body 41 having a spiral ridge 41a on a side surface and arranged in the internal space 40a. At an end of the container body 40, an intake port 40b for introducing the natural gas hydrate produced in the form of slurry in the production reactor 11 into the internal space 40a is provided. The above-described slurry pipe 37 is connected to the intake port 40b. The pressure in the internal space 40a is maintained at the gas hydrate generation pressure by communicating with the pressure vessel 20 via the slurry pipe 37.
[0027]
The container body 40 has a double structure of an inner wall 40c forming an inner space 40a and a housing 40d forming an outer shell. The inner wall 40c is mesh-processed, and filtered water accumulated inside the housing 40d. Is provided with a drain port 40e for discharging water. The housing 40d is directly connected to the pressure vessel 20 via a water pipe 44 connected to the drain 40e. The water pipe 44 is provided with a water pump 45 for introducing discharged water into the pressure vessel 20 and a valve 46.
[0028]
The shaft 41 is arranged so that the protruding ridge 41a is close to the inner surface of the internal space 40a, and is supported so as to be rotatable in a predetermined direction about its own axis. At the end of the container body 40, an outlet 40f for taking out the natural gas hydrate conveyed by the rotation of the shaft body 41 is provided. The container body 40 is connected to the subsequent twin screw type dehydrator 13 via a hydrate pipe 43 connected to an outlet 40f.
[0029]
The twin-screw dewatering device 13 includes a container body 50 having a cylindrical internal space 50a having an elliptical cross section, and spiral ridges 51a and 52a on the side surface. And two shafts 51 and 52 for conveying the natural gas hydrate while rotating. At the tip of the container body 50, an inlet 50b for taking in natural gas hydrate physically dehydrated in the screw press type dehydrator 12 is provided. The hydrate pipe 43 described above is connected to the intake port 50b. The pressure in the internal space 50a is maintained at the gas hydrate generation pressure by communicating with the internal space 40a of the screw press type dehydrator 12 via the hydrate pipe 43.
[0030]
The shaft bodies 51 and 52 are arranged in parallel with each other, and are arranged so that the respective ridges 51a and 52a are overlapped when viewed from the axial direction. Further, the respective protruding ridges 51a, 52a are arranged close to the inner surface of the internal space 50a, and are rotatably supported around their own axis. The rotation directions of the two shafts may be the same or different.
[0031]
At the end of the container 50, an outlet 50c for taking out the gas hydrate conveyed by the rotation of the shafts 51 and 52 is provided. The outlet 50c is connected via a hydrate pipe 54 to the screw conveyor type cooling device 14 at the subsequent stage. A gas supply hole 50d for supplying natural gas to the internal space 50a is provided on a side surface of the container body 50 near the outlet 50c. The gas supply hole 50d is connected to the gas storage unit 19 via a gas pipe 55 branched from the gas pipe 24. The gas pipe 55 is provided with a valve 56 and a flow control valve 57. On the other hand, a pressure gauge 58 for detecting the pressure of the internal space 50a is installed in the container body 50 near the inlet 50b, and the opening degree of the flow control valve 57 is determined based on the measurement value of the pressure gauge 58. Is controlled so that the internal pressure is always maintained at the gas hydrate generation pressure.
[0032]
The screw press type dewatering device 12 and the twin screw type dewatering device 13 are provided with a cooling device (not shown) for keeping the inside of the internal spaces 40 and 50 in the above-mentioned supercooled state.
[0033]
The screw conveyor type cooling device 14 includes a container body 60 having a cylindrical internal space 60a, and a shaft body 61 having a spiral ridge 61a on the side surface and arranged in the internal space 60a. At the tip of the container body 60, an intake port 60b for introducing the natural gas hydrate hydrated and dehydrated by the twin screw dehydrator 13 into the internal space 60a is provided. The hydrate pipe 54 described above is connected to the intake 60b. The shaft body 61 is arranged so that the protruding ridge portion 61a is close to the inner surface of the internal space 60a, is supported so as to be rotatable in a predetermined direction about its own axis, and is driven to rotate by a driving device 62. At the end of the container body 60, an outlet 60c for taking out the natural gas hydrate conveyed by the rotation of the shaft body 61 is provided. The outlet 60c is connected via a hydrate pipe 63 to the downstream valve switching type pressure reducing device 15. The pressure of the internal space 60a is maintained at the gas hydrate generation pressure by communicating with the internal space 50a of the twin-screw dehydrator 13 via the hydrate pipe 63.
[0034]
The container body 60 has a double structure of an inner wall 60d forming an inner space 60a and a housing 60e forming an outer shell, and a side surface of the housing 60e close to the outlet 60c has a gap with the inner wall 60d. A coolant inlet 60f for introducing the coolant is provided, and a coolant outlet 60g for leading the coolant is provided on a side surface of the housing 60e near the inlet 60b. A refrigerant pipe 65 connecting the refrigerant inlet 60f and the refrigerant outlet 60g is connected to the container body 60, and the refrigerant pipe 65 is provided with a refrigerant circulation pump 66 and a heat exchanger 67. The refrigerant is cooled by the heat exchanger 66, flows into the gap between the inner wall 60d and the housing 60e through the refrigerant pipe 65, and the dehydrated natural gas hydrate does not decompose even at low pressure. (.Degree. C. to -15.degree. C.).
[0035]
The valve switching type decompression device 15 includes two valves 71 and 72 provided in series with the hydrate pipe 63. The two valves 71 and 72 are arranged apart from each other, the hydrate pipe 63 passing through the valve 72 at the subsequent stage is open to the atmosphere, and the pressure press molding device 16 is provided at the subsequent stage. The press press molding apparatus 16 includes a fixed wall portion 75 and a plate 76 driven to be able to approach and separate from the wall portion 75.
[0036]
Generation of natural gas hydrate by the generation system configured as described above will be described.
First, raw water is introduced into the pressure vessel 20 from the water storage tank 17 to form an aqueous phase L. At the same time, natural gas is introduced into the pressure vessel 20 from the gas storage unit 19, and the pressure of the gas phase G is increased to the gas hydrate generation pressure. In addition, a stabilizer may be added to the raw water forming the aqueous phase L, if necessary. Next, the temperature of the aqueous phase L is cooled to a supercooled state, and thereafter, temperature management is performed so that this state is maintained.
[0037]
When the state of the temperature and pressure in the pressure vessel 20 is stabilized, a part of the raw water forming the aqueous phase L is withdrawn from the bottom of the pressure vessel 20 through the water pipe 30 and cooled again by the heat exchanger 32. Spray from 36 into the gas phase G. Water particles sprayed from the spray nozzle 36 fall toward the aqueous phase L while floating in the gas phase G. By forming a large amount of water particles in the gas phase G, the surface area of the water particles existing in the gas phase G, that is, the contact area with the natural gas forming the gas phase G becomes extremely large. On the surface of the water particles, a hydration reaction between water and natural gas occurs, and natural gas hydrate is generated. Since the temperature in the pressure vessel 20 is controlled to be higher than the freezing point, the raw water forming the aqueous phase L and the sprayed water particles do not freeze.
[0038]
The natural gas hydrate generated on the surface of the water particles falls as it is, and falls on the liquid surface of the aqueous phase L to form a natural gas hydrate layer. This natural gas hydrate is extracted from the slurry extraction port 20 a and sent to the screw press type dehydrator 12 through the slurry pipe 37. At this time, since the natural gas hydrate is recovered together with the raw water, a slurry having a very high water content is obtained.
[0039]
The natural gas hydrate in the form of slurry sent to the screw press type dewatering device 12 through the slurry pipe 37 is accommodated in the internal space 40a through the intake port 40b, and is conveyed in the axial direction by the rotation of the shaft body 41. It is physically dehydrated by being pressed. The excess water separated from the natural gas hydrate still contains a great deal of natural gas hydrate. Then, the surplus water is collected inside the housing 40d through the mesh of the inner wall 40c, discharged from the drain 40e, and introduced again into the pressure vessel 20 through the water pipe 44. The details of the operation of the driving device 42 will be described later.
[0040]
On the other hand, the natural gas hydrate that has undergone the physical dehydration is taken out of the screw press type dehydrator 12 through the outlet 40f and sent to the twin screw type dehydrator 13 through the hydrate pipe 43.
[0041]
The natural gas hydrate sent to the twin-screw dehydrator 13 is accommodated in the internal space 50a through the inlet 50b, and is conveyed in the axial direction by the rotation of the shafts 51 and 52. The remaining water in the process comes into contact with the natural gas supplied to the internal space 50a, and is cooled while being stirred while reacting the remaining water with the natural gas to hydrate.
[0042]
The natural gas hydrate contained in the internal space 50a is dehydrated by hydrating most of the remaining water with the unhydrated natural gas before reaching the outlet 50c, and as a result, the natural gas hydrate is dehydrated. Increase the amount of itself. The natural gas hydrate having undergone the hydration dehydration is taken out of the twin screw dehydrator 13 through the outlet 50C, and sent into the screw conveyor type cooling device 14 through the hydrate pipe 54.
[0043]
The natural gas hydrate sent to the screw conveyor type cooling device 14 is accommodated in the internal space 60a through the inlet 60b, and is conveyed in the axial direction by the rotation of the shaft 41, and in the process, the refrigerant circulates inside the container 60. Cooled by. The natural gas hydrate cooled to a low temperature below the freezing point is taken out of the screw conveyor type cooling device 14 through the outlet 60f and sent to the valve switching type pressure reducing device 15 through the hydrate piping 63.
[0044]
The valve switching type pressure reducing device 15 opens the upstream valve 71 and closes the downstream valve 72 to receive natural gas hydrate. Since natural gas hydrate accumulates between the valves 71 and 72, the valve 71 is closed when a certain amount is reached, and then the valve 72 is opened to reduce the natural gas hydrate between the valves 71 and 72 to atmospheric pressure. . The natural gas hydrate that has been depressurized is taken out of the valve switching type depressurizing device 15 and sent to the press press forming device 16.
[0045]
The natural gas hydrate fed into the press-molding apparatus 16 is pressed and solidified by the plate 76 against the wall 75. The molded and solidified natural gas hydrate is stored in a dedicated transport container (not shown), and stored and transported.
[0046]
Next, a more detailed structure of the driving device 42 for driving the screw press type dewatering device 12 is shown in FIG.
The driving device 42 includes a hydraulic motor 100 that rotationally drives the shaft 41, a tank 101 that stores hydraulic oil to be supplied to the hydraulic motor 100, an oil pipe 102 that guides hydraulic oil from the tank 101 to the hydraulic motor 100, The hydraulic pump 100 includes a hydraulic pump 101 that supplies hydraulic oil to the hydraulic motor 100 through a pipe 102 and an oil pipe 104 that returns hydraulic oil that has worked on the hydraulic motor 100 to the tank 101.
[0047]
The hydraulic motor 100 is housed in a housing 100a integrated with the housing 40d of the screw press type dewatering device 12, and is connected to the base end of the shaft body 41 via a coupling (shaft joint) (not shown) ( The driving pressure of the hydraulic motor 100 is 10.0 MPa). The housing 100a has a pressure-resistant structure, and its internal pressure is maintained at a gas hydrate generation pressure by communicating with the internal space 40a of the container body 40.
[0048]
The tank 101 has the same pressure-resistant structure as the housing 100a, and is connected to the upper part of the pressure vessel 20 of the production reactor 11 via the equalizing tube 105, and the internal pressure is maintained at the production pressure of gas hydrate. (The pressure vessel 20 and the pressure equalizing tube 105 form a precompression means). The oil pipes 102 and 104 are provided so as to penetrate the casing 100a, and the space between each pipe and the casing 100a is strictly sealed so that airtightness is maintained. The hydraulic pump 103 is driven by an electric motor 103a.
[0049]
An auxiliary tank 106, an oil pipe 107 for guiding the hydraulic oil from the auxiliary tank 106 to the tank 101, and a supply of the hydraulic oil to the tank 101 through the oil pipe 107 are supplied to the tank 101 as replenishing means for supplementing the decrease in the hydraulic oil. A hydraulic pump 108 is provided. The auxiliary tank 106 is open to the atmosphere, and although not shown, drains from the hydraulic motor 100 and the hydraulic pumps 103 and 108 are collected. The hydraulic pump 108 is driven by an electric motor 108a.
[0050]
In the driving device 42 configured as described above, the hydraulic oil in the tank 101 is pressurized to the same pressure (5.0 MPa) as the gas hydrate generation pressure. When the hydraulic pump 103 is driven to perform dehydration by the screw press type dehydrator 12, the pressurized hydraulic oil is supplied to the hydraulic motor 100 through the oil pipe 102. The hydraulic pump 103 works to increase the operating oil to a pressure (15.0 MPa) obtained by adding the driving pressure (10.0 MPa) of the hydraulic motor 100 to the internal pressure (5.0 MPa) of the housing 100 a. When the pressure of the hydraulic oil rises to a desired pressure (15.0 MPa), the hydraulic motor 100 is driven, and the shaft 41 is rotationally driven. Thereby, the slurry-like natural gas hydrate accommodated in the internal space 40a is physically dehydrated. The working oil that has worked on the hydraulic motor 101 is returned to the tank 101 through the oil pipe 104.
[0051]
If the operation is continued, it is inevitable that oil is discharged from the hydraulic motor 100 or the hydraulic pumps 103 and 108, but the oil is returned to the auxiliary tank 106. When drainage occurs, the amount of hydraulic oil flowing through the hydraulic circuit constituted by the tank 101, the hydraulic pump 103, the hydraulic motor 100, and the oil pipes 102 and 104 decreases. Therefore, the hydraulic pump 108 is driven at an appropriate time, and the auxiliary hydraulic oil is pushed into the tank 101 from the auxiliary tank 106 to be replenished.
[0052]
According to the above-described drive device, the work that the hydraulic pump 103 should perform to drive the hydraulic motor 100 is only the amount of pressurizing the operating oil pressurized to 5.0 MPa from the beginning to 15.0 MPa, that is, the difference. It is only necessary to increase the pressure by 10.0 MPa. Therefore, the energy consumption of the electric motor 103a for driving the hydraulic pump 103 can be reduced.
[0053]
Further, although the shaft body 40 straddles the internal space 40a and the housing 100a, they are both pressurized to the generation pressure of the gas hydrate, so that it is not necessary to secure airtightness in the partition part separating them. It is safe. Further, there is no need to install a complicated and expensive mechanism such as a shaft sealing device in order to secure airtightness.
[0054]
In the present embodiment, the pressure vessel 20 as a pressure source for pressurizing the inside of the housing 100a is shared as a pressure source for pressurizing the inside of the tank 101, and 5.0 MPa of the generated pressure is offset. The pressure source is not limited to the pressure vessel 20, and any pressure source that can obtain a pressure higher than the atmospheric pressure may be used. If there is one that can obtain a higher pressure than the pressure vessel 20, it should be adopted. However, these pressure sources are meaningless if they require power to pressurize the tank 101, and are limited to those that can use excess pressure.
[0055]
Further, in the present embodiment, only the driving device 42 of the screw press type dewatering device 12 has been described, but the same mechanism may be adopted for each driving device of the twin screw type dewatering device 13 and the screw conveyor type cooling device 14. it can.
[0056]
Further, in the present embodiment, an example in which the drive device by the hydraulic motor of the present invention is applied to each drive device provided in the natural gas hydrate generation system, but the present invention is applied to a natural gas hydrate generation system. The present invention is not limited to this, and can be applied to a device that drives some mechanism under a pressure higher than the atmospheric pressure. An example is a submarine drilling rig. In this case, the water pressure at the sea bottom is used as the pressure source.
[0057]
【The invention's effect】
As described above, according to the present invention, since the hydraulic motor is installed in the housing of the pressurized atmosphere similarly to the machine to be driven, it is not necessary to provide the shaft sealing device, so that the structure is simplified. The cost for installation can be kept low.
[0058]
Also, by pre-pressurizing the hydraulic oil to drive the hydraulic motor using excess pressure and setting it higher than the atmospheric pressure, the work required to drive the hydraulic motor is reduced by the amount of preload. Since it is less, the energy consumed to drive the hydraulic motor can be saved.
[0059]
Further, by sharing the pressure source of the preload means with the pressure source for pressurizing the inside of the housing, the work to be performed to drive the hydraulic motor is offset by the atmospheric pressure, and the normal driving pressure is only used. Since the pressure increase is sufficient, further energy reduction is possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing a specific device configuration of a natural gas hydrate generation device of the present invention.
FIG. 2 is a diagram showing a more detailed structure of a driving device of a screw press type dehydrator and peripheral devices thereof.
[Explanation of symbols]
11 Production reactor
12 Screw press type dehydrator
20 pressure vessel
42 Drive
100 hydraulic motor
100a housing
101 tank
102 Oil piping
103 Hydraulic pump
104 oil piping
105 Equalizing tube

Claims (6)

A drive device using a hydraulic motor, wherein a driven machine is installed in a housing held at a pressure higher than the atmospheric pressure, and a hydraulic motor for driving the driven machine is installed in the housing. 2. The driving device according to claim 1, further comprising a pre-compression unit that pre-pressurizes hydraulic oil to be driven by the hydraulic motor so as to be higher than atmospheric pressure. 3. The driving device according to claim 2, wherein a pressure source of the preload means is common to a pressure source for pressurizing the inside of the housing. 4. The drive device according to claim 2, further comprising a replenishing unit that compensates for a decrease in the hydraulic oil. A screw press type dehydrating apparatus comprising: a container body having an inside maintained at a pressure higher than the atmospheric pressure; and
A screw press, characterized in that the shaft body disposed inside the container body is a driven machine, and the drive device by a hydraulic motor according to any one of claims 1 to 4 is installed to drive the shaft body. Mold dehydrator. A natural means comprising a generating means for generating natural gas hydrate by reacting natural gas and raw water in a generating vessel held at a pressure higher than the atmospheric pressure, and a dehydrating means for dehydrating the generated natural gas hydrate. A gas hydrate generation system,
The dehydrating means includes a container body having an interior maintained at a pressure higher than the atmospheric pressure, and a shaft body having a spiral ridge on a side surface and arranged in an internal space of the container body,
A natural gas, characterized in that the shaft body disposed inside the container body is a driven machine, and the drive device by a hydraulic motor according to any one of claims 1 to 4 is installed to drive the shaft body. Hydrate generation system.

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