A bulk natural gas hydrate synthesis apparatus and method

Abstract

The application discloses a kind of block natural gas hydrate synthesis device and method, belong to natural gas hydrate synthesis technical field.Synthesis device mainly includes high-pressure stirred tank, flow guide pipe, pressurized piston tank, gas-liquid injection device, hydraulic drive device and data acquisition device.The application uses the method that high-pressure stirred tank fully stirs gas-liquid, promotes hydrate slurry to form rapidly in large quantities, then hydrate slurry is transferred to pressurized piston tank by flow guide pipe, and then excess water is removed by using hydraulic drive piston to slurry, so that slurry hydrate particles are consolidated into block natural gas hydrate.The application can prepare large-size, high-purity, regular-shaped block natural gas hydrate, and the device structure is simple, the synthesis process is rapid, and the sample size is controllable, which can provide a basis for further development of block natural gas hydrate technology research and development.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of natural gas hydrate synthesis, and particularly relates to a device and method for synthesizing blocky natural gas hydrate. BACKGROUND

[0002] Natural gas hydrate is a cage-shaped crystalline substance formed by hydrocarbon gas and water under high pressure and low temperature conditions. Natural gas hydrate is mainly distributed in the seabed sediment layer of the sea area and the permafrost region on land, and has different occurrence states in different regions. According to the hydrate exploration drilling of various countries, the distribution patterns of natural gas hydrate in nature include dispersed, layered, veined, disseminated, nodular and blocky, etc. To develop blocky hydrate resources, it is necessary to first synthesize blocky hydrate samples in the laboratory to provide physical samples for related experimental tests.

[0003] At present, most experiments mainly study the synthesis of hydrate in sediments, including coarse-grained sediments such as sandy particles and fine-grained sediments such as silica powder, diatom, kaolinite and bentonite, and the synthesized hydrate state is mainly dispersed, thin-layered and veined. In comparison, the synthesis experiment of blocky hydrate is relatively weak, and the blocky samples synthesized by existing experiments are very small in size, which cannot provide theoretical support for the trial mining of blocky hydrate in nature.

[0004] Therefore, there is an urgent need in the prior art for a new technical solution to solve this problem. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a device and method for synthesizing blocky natural gas hydrate to solve the technical problem that the blocky natural gas hydrate samples synthesized by existing experiments are very small in size and cannot provide theoretical support for the trial mining of blocky hydrate in nature.

[0006] A kind of block natural gas hydrate synthesis device, the device is placed in high-low temperature test chamber when using, including gas-liquid injection device, high-pressure stirred tank, flow guide pipe, pressurized piston tank, hydraulic drive device and data acquisition device, the gas / liquid inlet of high-pressure stirred tank is fixedly connected with gas-liquid injection device, high-pressure stirred tank is provided with stirrer in the inside, high-pressure stirred tank is also provided with exhaust port on the side wall, the discharge port of high-pressure stirred tank is connected with the feed inlet of flow guide pipe by pipeline and ball valve I;The stirrer is connected with stirring motor;Pressurized piston tank is transversely arranged, one end of pressurized piston tank is connected with tank cover, piston is arranged in the inside of pressurized piston tank, the other end bottom of pressurized piston tank is communicated with external hydraulic drive device by pipeline;The discharge port of flow guide pipe is connected with tank cover by ball valve II;Drainage port is provided on the tank cover;Stop valve I and back pressure valve I are connected on the drainage port;Stop valve III is arranged on the pipeline that hydraulic drive device is connected with pressurized piston tank, stop valve II and back pressure valve II are sequentially connected by branch pipeline on the pipeline between pressurized piston tank and stop valve III;

[0007] The data acquisition device includes speed regulator arranged on stirring motor, thermal resistance I and pressure sensor I arranged in high-pressure stirred tank, thermal resistance II and pressure sensor II arranged in the inside of tank cover, pressure sensor arranged on hydraulic drive device and computer;The computer is respectively connected with speed regulator, thermal resistance I, pressure sensor I, thermal resistance II, pressure sensor II and pressure sensor.

[0008] The gas-liquid injection device includes high-pressure gas cylinder, pressure reducing valve and horizontal flow pump;The high-pressure gas cylinder is connected with the gas / liquid inlet of high-pressure stirred tank by pressure reducing valve and pipeline;The horizontal flow pump is connected with the gas / liquid inlet of high-pressure stirred tank by pipeline.

[0009] The hydraulic drive device is horizontal flow pump.

[0010] The stirrer is provided with a plurality of stirring blades, and a plurality of columnar stirring teeth with different heights are arranged on each stirring blade.

[0011] The inside of the drainage port is provided with replaceable screen.

[0012] A block natural gas hydrate synthesis method utilizes the block natural gas hydrate synthesis device, includes the following steps, and the following steps are sequentially performed:

[0013] Step one, preparation:

[0014] Put the block hydrate synthesis device in the high-low temperature test box, reduce the temperature of the high-low temperature test box to the specified constant low temperature, which is generally required to be in the range of 0℃ to 20℃, and the hydraulic drive device pushes the piston to the kettle cover to make the piston adhere to the kettle cover. Close the stop valve I, the stop valve II and the stop valve III, open the ball valve I and the ball valve II, pre-inject natural gas into the high-pressure stirred kettle, the drainage guide pipe and the pressurized piston tank from the high-pressure gas cylinder, close the ball valve I and the ball valve II, open the stop valve I and the stop valve II, adjust the back pressure valve I and the back pressure valve II to make the pressure on both sides of the piston in the pressurized piston tank reach the set value, to ensure that the pressure in the pressurized piston tank is higher than the hydrate equilibrium pressure during the pressure maintaining transfer of the natural gas hydrate slurry, and then close the stop valve I;

[0015] Step two, stirring synthesis:

[0016] Inject natural gas into the high-pressure stirred kettle from the high-pressure gas cylinder until the high pressure, which is higher than the phase equilibrium pressure of the natural gas hydrate under the temperature condition set in step one, inject deionized water or salt solution into the high-pressure stirred kettle from the gas-liquid injection device, the salt solution can contain one or more of sodium, potassium, magnesium and calcium chloride and sulfate, adjust the liquid inlet depth of the stirrer, control the stirring rate of the stirrer by adjusting the stirring motor, and fully stir the gas-liquid by using the multiple height columnar stirring teeth of the stirrer to synthesize the natural gas hydrate slurry;

[0017] Step three, pressure maintaining transfer:

[0018] The high-pressure gas cylinder continuously supplies natural gas into the high-pressure stirred kettle to maintain the constant pressure of the hydrate slurry, and the pressure is higher than the phase equilibrium pressure of the natural gas hydrate under the low temperature condition set in step one; reduce the temperature of the high-low temperature test box to the specified low temperature to provide low temperature conditions for the pressure consolidation and molding of the hydrate slurry; open the ball valve I and the ball valve II, and the hydrate slurry enters the pressurized piston tank from the high-pressure stirred kettle through the drainage guide pipe under the action of pressure difference, and then close the ball valve I and the ball valve II;

[0019] Step four, pressure molding:

[0020] Close the stop valve II, open the stop valve I and the stop valve III, and use the hydraulic drive device to push the piston to press the hydrate slurry according to the set pressure value, which should be higher than the phase equilibrium pressure of the natural gas hydrate under the low temperature condition set in step three, in order to push the piston to discharge the excess water from the drain, and the hydrate in the pressurized piston tank is consolidated into a columnar block under pressure, and the low temperature pressure maintaining is kept for more than 1h, adjust the back pressure valve I at the drain to open the kettle cover of the pressurized piston tank, open the kettle cover of the pressurized piston tank, use the hydraulic drive device to push the piston to quickly push out the blocky natural gas hydrate, and store it at low temperature.

[0021] Through the above design scheme, the present application can bring the following beneficial effects:

[0022] 1. The synthesis device utilizes multiple height-differentiated columnar stirring teeth to form a mountain-shaped stirring paddle with multiple stages of teeth, reduces the stirring resistance of viscous slurry by stirring gas-liquid-solid mixture, reduces the risk of stirring paddle stall, effectively breaks the hydrate layer formed on the gas-liquid interface, maximizes the gas-liquid contact area, promotes continuous and sufficient reaction of gas and liquid, and accelerates the synthesis of natural gas hydrate;

[0023] 2. The synthesis device utilizes a ball valve and a drainage guide tube to connect the high-pressure stirring kettle and the pressurized piston tank, enables the hydrate slurry stirring synthesis and pressurized consolidation processes to operate independently, thereby realizing the rapid synthesis of large-size block-shaped hydrate; according to the size requirement of the synthesized sample, a sufficient amount of hydrate slurry can be synthesized multiple times, transferred to the pressurized piston tank in an intermittent manner, and pressurized to drain water to form a regular cylindrical hydrate sample; or different volume pressurized piston tanks can be replaced according to the size requirement of the sample. The present application can prepare large-size, high-purity, and regularly-shaped block-shaped natural gas hydrate, and has simple device structure, rapid synthesis process, and controllable sample size, which can provide a basis for further technical research and development of block-shaped natural gas hydrate. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application will be further described below in combination with the drawings and specific embodiments:

[0025] Figure 1 The device structure in the present application is a block-shaped natural gas hydrate synthesis device and method.

[0026] In the figure, 1 is a high-pressure stirring kettle, 2 is a stirring motor, 3 is a stirrer, 4 is a thermal resistance I, 5 is a pressure sensor I, 6 is an exhaust port, 7 is an air / gas inlet, 8 is a ball valve I, 9 is a drainage guide tube, 10 is a ball valve II, 11 is a pressurized piston tank, 12 is a water outlet, 13 is a thermal resistance II, 14 is a pressure sensor II, 15 is a stop valve I, 16 is a back pressure valve I, 17 is a piston, 18 is a stop valve II, 19 is a back pressure valve II, 20 is a stop valve III, 21 is a horizontal flow pump, 22 is a pressure reducing valve, 23 is a high-pressure gas cylinder, 24 is a hydraulic drive device, 25 is a computer, 26 is a kettle cover, and 27 is a columnar stirring tooth. DETAILED DESCRIPTION

[0027] The present application will be further described below in combination with the drawings and specific embodiments:

[0028] EMBODIMENT

[0029] Figure 1 The device structure in the present application is a block-shaped natural gas hydrate synthesis device and method.

[0030] The high-pressure stirred tank 1 is a cylindrical cavity, and the inside of the high-pressure stirred tank 1 is provided with a stirrer 3. The top of the cover of the high-pressure stirred tank 1 is provided with a stirring motor 2, and the stirring motor 2 is provided with a speed regulator, so that the stirring motor 2 can be adjusted in speed. The upper part of the stirring shaft of the stirrer 3 is connected with the stirring motor 2, and the lower part of the stirring shaft is connected with a multi-stage toothed mountain-shaped stirring paddle with different heights of columnar stirring teeth 27. Four interfaces are arranged on the high-pressure stirred tank 1, which are respectively a gas / liquid inlet 7, an exhaust port 6, a thermal resistance interface for installing a thermal resistance I 4, and a pressure sensor interface for installing a pressure sensor I 5. The high-pressure stirred tank 1 is used for fully stirring gas and liquid in a high-pressure and low-temperature environment, and rapidly synthesizing a large amount of natural gas hydrate slurry;

[0031] One end of the drainage guide pipe 9 is welded with the bottom of the high-pressure stirred tank 1, and the drainage guide pipe 9 is connected with a ball valve I 8 and a ball valve II 10 with the same inner diameter, which are used for pressure maintaining and transferring of the hydrate slurry;

[0032] The pressurizing piston tank 11 is internally provided with a piston 17. The cover 26 of the pressurizing piston tank 11 is screw-connected with the tank body of the pressurizing piston tank 11. The cover 26 is connected with the ball valve II 10. The cover 26 is provided with a thermal resistance interface for installing a thermal resistance II 13 and a pressure sensor interface for installing a pressure sensor II 14. Two drainage ports 12 are arranged on the side surface of the cover 26. The hydraulic driving device 24 drives the piston 17 to press the hydrate slurry, and the excess water is discharged through the drainage port 12. The hydrate slurry is solidified into block-shaped hydrate under the condition of low temperature and high pressure. The drainage port 12 is connected with a stop valve I 15 and a back pressure valve I 16;

[0033] The gas-liquid injection device includes a high-pressure gas cylinder 23, a pressure reducing valve 22 and an advection pump 21. The gas-liquid injection device is connected with the gas / liquid inlet 7, and is used for providing natural gas and deionized water or salt solution into the cavity of the high-pressure stirred tank 1. The natural gas includes one or several mixtures of CH4, C2H6, C3H8, CO2 and N2. The deionized water or salt solution is used for simulating seawater environment. The solute of the salt solution can be one or several of chlorides or sulfates of sodium, potassium, magnesium and calcium;

[0034] The hydraulic driving device 24 is an advection pump. The hydraulic driving device 24 is connected with the pressurizing piston tank 11, and is used for controlling the movement of the piston 17. The pipeline connected with the pressurizing piston tank 11 is provided with a stop valve III 20. The pipeline between the pressurizing piston tank 11 and the stop valve III 20 is further connected with a stop valve II 18 and a back pressure valve II 19 through a branch pipeline in sequence;

[0035] The data acquisition device comprises a speed regulator arranged on the stirring motor 2, a thermal resistance I4 and a pressure sensor I5 arranged inside the high-pressure stirred tank 1, a thermal resistance II 13 and a pressure sensor II 14 arranged inside the tank cover 26, a pressure sensor arranged on the hydraulic drive device 24, and a computer 25; the computer 25 is in communication connection with the speed regulator, the thermal resistance I4, the pressure sensor I5, the thermal resistance II 13, the pressure sensor II 14 and the pressure sensor respectively, and is used for recording the related data of the process of synthesizing the blocky natural gas hydrate in real time.

[0036] The process of synthesizing the blocky natural gas hydrate according to the present application is described in detail below.

[0037] Step one, preparation:

[0038] 1. The instrument is cleaned with deionized water, and the blocky natural gas hydrate synthesizing device is assembled;

[0039] 2. The synthesizing device is placed in the high-low temperature test box, the temperature of the high-low temperature test box is reduced to 5.0℃ and maintained constant, the hydraulic drive device 24 pushes the piston 17 to the initial position, and the initial position is located at the tank cover 26 of the pressurized piston tank 11;

[0040] 3. The stop valve I 15, the stop valve II 18 and the stop valve III 20 are closed, the ball valve 8 and the ball valve 10 are opened, and the natural gas is pre-injected into the high-pressure stirred tank 1, the drainage guide pipe 9 and the pressurized piston tank 11 from the high-pressure gas cylinder 23, the natural gas can be one or a mixture of several of CH4, C2H6, C3H8, CO2 and N2, and in this example, the natural gas is CH4 gas; the natural gas is injected into the device to a specified high pressure value, the selection of the high pressure value is associated with the specified constant low temperature in step 2, and the pressure should be significantly higher than the hydrate phase equilibrium pressure of the natural gas under the low temperature condition in step 2, so as to promote the synthesis of the hydrate. For example, the temperature of the high-low temperature test box in step 2 is set to 5.0℃ and maintained constant, and the high pressure value is selected to be 8.0MPa; the temperature of the high-low temperature test box in step 2 is set to 1.0℃ and maintained constant, and the high pressure value can be selected to be 6.0MPa;

[0041] 4. The ball valve I 8 and the ball valve II 10 are closed, the stop valve I 15 and the stop valve II 18 are opened, the back pressure valve I 16 at the water outlet 12 is adjusted to a control pressure value of 3.5MPa, the back pressure valve II 19 at the bottom of the pressurized piston tank is adjusted to a control pressure value of 3.0MPa, the pressure on both sides of the piston 17 in the pressurized piston tank 11 is set, and the pressure in the pressurized piston tank 11 can be maintained at 3.0MPa-3.5MPa in the subsequent steps three and four, which is higher than the CH4 hydrate phase equilibrium pressure at 0.5℃, and then the stop valve I 15 is closed.

[0042] Step two, stirring synthesis:

[0043] 1. Inject natural gas into the high-pressure stirred tank 1 from the high-pressure cylinder 23, and the pressure reaches 8.0 MPa. Then, inject deionized water or salt solution into the high-pressure stirred tank 1 from the flow pump 21.

[0044] 2. Adjust the liquid inlet depth of the stirrer 3, and control the stirring rate by adjusting the stirring motor 2. Use the multiple columnar stirring teeth 27 of different heights of the stirrer 3 to fully stir the gas-liquid, and synthesize a large amount of natural gas hydrate slurry.

[0045] Step three, pressure transfer:

[0046] 1. Adjust the output pressure of the pressure reducing valve 22, so that the high-pressure cylinder 23 continuously supplies natural gas to the high-pressure stirred tank 1, maintains the hydrate slurry pressure constant, and keeps it above 4.5 MPa.

[0047] 2. Reduce the temperature of the high-low temperature test chamber to 0.5℃, to provide low-temperature conditions for the transfer and pressure consolidation of the hydrate slurry.

[0048] 3. Open the ball valve I 8 and the ball valve II 10. The hydrate slurry is transferred from the high-pressure stirred tank 1 to the pressurized piston tank 11 through the drainage guide pipe 9 under the action of pressure difference, to realize pressure transfer. Then, close the ball valve I 8 and the ball valve II 10.

[0049] 4. If the amount of transferred hydrate slurry is less than the required liquid amount for the target size, continue to inject natural gas and deionized water or salt solution into the high-pressure stirred tank 1 through the high-pressure cylinder 23 and the flow pump 21, and synthesize the required hydrate slurry by stirring.

[0050] Step four, pressure forming:

[0051] 1. Close the stop valve II 18, open the stop valve I 15 and the stop valve III 20, and use the hydraulic drive device 24 to push the piston 17 to press the hydrate slurry at a pressure not less than 3.0 MPa. The pressure is higher than the phase equilibrium pressure of natural gas hydrate at 0.5℃, which is to push the piston. The hydraulic drive device 24 can increase the pressure according to the increase of the piston movement resistance, and discharge the excess water from the drain port 12. The hydrate in the pressurized piston tank 11 is consolidated into a cylindrical block under pressure, and is kept at low temperature and pressure for more than 1h.

[0052] 2. Adjust the back pressure valve I 16 at the drain port 12 to release pressure, open the tank cover 26 of the piston tank 11, and use the hydraulic drive device 24 to push the piston 17 to quickly push out the block-shaped natural gas hydrate, and keep it at low temperature.

[0053] In summary, the application is a kind of synthesis device of block natural gas hydrate, mainly applied to the simulation synthesis technology of various occurrence states of natural gas hydrate, the research mechanism of hydrate slurry fluid dynamics and the research of hydrate blocking and gathering pipeline, etc. The device can carry out synthesis experiments of different types of block hydrate, so as to explore the influence of temperature and pressure conditions, gas type and stirring rate on the volume fraction of hydrate; it can also provide samples for carrying out experimental research on the properties of block hydrate. In addition, the device can quantitatively analyze the flow characteristics of hydrate slurry in the process of conduit drainage, including the influence of pressure difference, slurry viscosity and conduit inner diameter on the slurry flow velocity, and explore the mechanism of hydrate slurry gathering and blocking pipeline in the conduit inner wall, and put forward the prevention and control method. Most importantly, the device can independently operate the stirring synthesis and pressure forming parts, improve the operation efficiency, and quickly and continuously prepare large-size, high-purity block hydrate samples.

[0054] The above examples illustrate the research ideas and implementation modes of the application, which are used to better understand the research content of the application, and cannot limit the protection scope of the application. Any equivalent modification or change according to the application belongs to the patent scope of the application.

Claims

1. A device for synthesizing blocky natural gas hydrates, wherein the device is placed inside a high and low temperature test chamber during use, characterized in that: The system includes a gas-liquid injection device, a high-pressure mixing vessel (1), a drainage conduit (9), a pressurized piston tank (11), a hydraulic drive device (24), and a data acquisition device. The gas / liquid inlet (7) of the high-pressure mixing vessel (1) is fixedly connected to the gas-liquid injection device. A stirrer (3) is installed inside the high-pressure mixing vessel (1). An exhaust port (6) is also provided on the side wall of the high-pressure mixing vessel (1). The lower outlet of the high-pressure mixing vessel (1) is connected to the inlet of the drainage conduit (9) through a pipeline and a ball valve I (8). The stirrer (3) is connected to a stirring motor (2). The pressurized piston tank (11) is arranged horizontally, and one end of the pressurized piston tank (11) is connected to a vessel cover (26). (11) has an internal piston (17), and the bottom of the other end of the pressurized piston tank (11) is connected to the external hydraulic drive device (24) through a pipeline; the outlet of the drainage pipe (9) is connected to the lid (26) through ball valve II (10); the lid (26) is provided with a drain outlet (12), and the drain outlet (12) is connected with a stop valve I (15) and a back pressure valve I (16); the pipeline connecting the hydraulic drive device (24) and the pressurized piston tank (11) is provided with a stop valve III (20), and the pipeline between the pressurized piston tank (11) and the stop valve III (20) is also connected with a stop valve II (18) and a back pressure valve II (19) in sequence through a branch pipeline; The data acquisition device includes a speed controller installed on the stirring motor (2), a thermal resistor I (4) and a pressure sensor I (5) installed inside the high-pressure stirring vessel (1), a thermal resistor II (13) and a pressure sensor II (14) installed inside the vessel cover (26), a pressure sensor installed on the hydraulic drive device (24), and a computer (25); the computer (25) is communicatively connected to the speed controller, the thermal resistor I (4), the pressure sensor I (5), the thermal resistor II (13), the pressure sensor II (14), and the pressure sensor.

2. The apparatus for synthesizing blocky natural gas hydrates according to claim 1, characterized in that: The gas-liquid injection device includes a high-pressure gas cylinder (23), a pressure reducing valve (22), and a horizontal flow pump (21); the high-pressure gas cylinder (23) is connected to the gas / liquid inlet (7) of the high-pressure stirred tank (1) through the pressure reducing valve (22) and pipeline; the horizontal flow pump (21) is connected to the gas / liquid inlet (7) of the high-pressure stirred tank (1) through pipeline.

3. The apparatus for synthesizing blocky natural gas hydrates according to claim 1, characterized in that: The hydraulic drive device (24) is a horizontal flow pump.

4. The apparatus for synthesizing blocky natural gas hydrates according to claim 1, characterized in that: The stirrer (3) is provided with multiple stirring blades, and each stirring blade is provided with multiple columnar stirring teeth (27) of different heights.

5. The apparatus for synthesizing blocky natural gas hydrates according to claim 1, characterized in that: The drain outlet (12) is equipped with a replaceable screen.

6. A method for synthesizing bulk natural gas hydrate, utilizing the bulk natural gas hydrate synthesis apparatus according to claim 1, characterized in that: It includes the following steps, and the following steps are performed in sequence. Step 1: Preparations The block hydrate synthesis device is placed in a high and low temperature test chamber. The temperature of the high and low temperature test chamber is lowered to between 0℃ and 20℃. The hydraulic drive device (24) pushes the piston (17) to the vessel lid (26) so that the piston (17) fits against the vessel lid (26). The shut-off valves I (15), II (18) and III (20) are closed, and the ball valves I (8) and II (10) are opened. The high-pressure gas cylinder (23) is used to pre-fill the high-pressure stirred vessel (1) and the drainage pipe (9). Natural gas is injected into the pressurized piston tank (11), ball valve I (8) and ball valve II (10) are closed, and shut-off valve I (15) and shut-off valve II (18) are opened. By adjusting back pressure valve I (16) and back pressure valve II (19), the pressure on both sides of the piston (17) in the pressurized piston tank (11) reaches the set value, so as to ensure that the pressure in the pressurized piston tank (11) is higher than the hydrate equilibrium pressure during the pressure holding and transfer of natural gas hydrate slurry. Then shut-off valve I (15) is closed. Step 2: Stirring and Synthesis: Natural gas is injected into the high-pressure stirred tank (1) from the high-pressure gas cylinder (23) to a high pressure. The high pressure value is higher than the phase equilibrium pressure of natural gas hydrate under the temperature conditions set in the high and low temperature test chamber in step one. Deionized water or salt solution is injected into the high-pressure stirred tank (1) by the horizontal flow pump (21) in the gas-liquid injection device. The liquid immersion depth of the stirrer (3) is adjusted. The stirring speed of the stirrer (3) is controlled by adjusting the stirring motor (2). The gas and liquid are fully stirred by the multiple columnar stirring teeth (27) of the stirrer (3) with different heights to synthesize natural gas hydrate slurry. Step 3: Pressure Holding and Transfer The high-pressure gas cylinder (23) continuously supplies natural gas into the high-pressure stirring vessel (1) to maintain the constant pressure of the hydrate slurry, and lowers the temperature of the high and low temperature test chamber to the specified low temperature to provide low temperature conditions for the transfer and pressure solidification of the hydrate slurry. The ball valve I (8) and ball valve II (10) are opened, and the hydrate slurry enters the pressurized piston tank (11) from the high-pressure stirring vessel (1) through the drainage pipe (9) under the action of pressure difference. The ball valve I (8) and ball valve II (10) are closed. Step 4: Pressure molding: Close shut-off valve II (18), open shut-off valve I (15) and shut-off valve III (20), use hydraulic drive device (24) to push piston (17) to pressurize hydrate slurry according to the set pressure value, discharge excess water from drain (12), hydrate in pressurized piston tank (11) solidifies into columnar block shape under pressure, keep low temperature and pressure for more than 1 hour, adjust back pressure valve I (16) at drain (12) to release pressure and open the lid (26) of pressurized piston tank (11), use hydraulic drive device (24) to push piston (17) to quickly push out block natural gas hydrate, and store at low temperature.

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