Continuous preparation device and method for hydrate-in-ice blocks

Abstract

The invention belongs to the field of carbon dioxide sealing and storage and hydrate technology application, and discloses a continuous preparation device and method for an ice-in-water hydrate block. The continuous preparation device for the hydrate-in-ice blocks comprises a hydrate generating and briquetting unit, a coated ice shell preparation unit, a hydrate-in-ice block storage, transportation and collection unit, a constant-temperature box body, a telescopic rotating shaft structure, a gas injection system, a liquid injection system and a motor. A screen type piston is arranged in the hydrate generating and briquetting unit, and generated flocculent hydrates are compacted to be cylindrical; the ice shell coating unit constructs a compact ice shell protection shell outside the cylindrical hydrate block; the ice-in-ice hydrate block storage and transportation and collection unit is used for automatically transporting and storing the prepared normalized sample blocks; the gas-liquid injection system is used for transporting hydrate generation raw materials and ice-making raw materials into the device; the telescopic rotating shaft structure enables the device to be turned according to a preset angle in the vertical direction and can control horizontal and vertical displacement of the tray type piston, so that sample preparation and collection are facilitated.

Description

Technical Field

[0001] The invention belongs to the field of carbon dioxide storage and hydrate technology application, and relates to an ice pack carbon dioxide hydrate block preparation device and method. Background Art

[0002] As one of the components of the CCUS technology chain, carbon storage technology plays a key role in determining carbon reduction. Currently, commonly used carbon storage technologies include ocean storage, geological storage, and biochemical storage. However, the cost of drilling wells for ocean carbon storage is high, biochemical storage takes a long time, and geological storage also has application bottlenecks such as immature technology. Combined with the natural properties of permafrost areas that are in the sub-zero temperature range all year round, and the physical characteristics of hydrates with high gas storage density and stable storage under suitable temperature and pressure environments, it is believed that the application of hydrate technology in permafrost areas to achieve long-term and stable geological carbon storage has great development prospects. The underlying support of this technology is the abnormal decomposition behavior of hydrates in a low-temperature environment below the freezing point, in which the decomposition is slow or stagnant. In this process, the formation of ice shell is the key factor in inhibiting the decomposition efficiency. Taking this abnormal decomposition phenomenon as an application template, the invention concept of realizing carbon sequestration in permafrost areas with the help of ice-pack hydrates was proposed, and then the device and related sample preparation methods were designed. In engineering practice, the industrial batch preparation of ice-pack hydrate blocks was completed with the help of this device and preparation method, which was used in scenarios such as long-distance cold chain transportation of hydrates and carbon sequestration in permafrost environments, playing a positive role in promoting the industrial application of hydrate-based carbon sequestration in permafrost areas. Summary of the invention

[0003] In view of the many bottlenecks in the application of existing carbon storage technology, the present invention proposes a method for preparing ice pack hydrate blocks and a supporting device design, which can bury the prepared ice pack hydrate blocks in frozen soil layers to achieve long-term and stable geological carbon storage, and the storage cost is significantly reduced.

[0004] The technical solution of the present invention:

[0005] An ice pack hydrate block preparation device comprises a hydrate generation and briquetting unit, an ice shell preparation unit, an ice pack hydrate block storage, transportation and collection unit, a constant temperature box, a gas supply system, a liquid supply system and a telescopic arm type rotating shaft structure.

[0006] The hydrate generation and briquetting unit is a cylindrical stainless steel pressure vessel, which is located in the upper area of ​​the ice pack hydrate block preparation device, and is provided with a screen piston with a screen aperture of 200 meshes, and the piston push rod is connected to the motor. The cavity side wall of the hydrate generation and briquetting unit is provided with a gas passage and a liquid passage, the gas passage is connected to the hydrate generation and compaction unit and the high-pressure gas storage cylinder, the liquid passage is connected to the hydrate generation and compaction unit and the methionine solution storage tank, and the cavity side wall of the hydrate generation and briquetting unit is provided with a fixed site, which is connected to the rotating shaft support;

[0007] The coating ice shell preparation unit is a cylindrical stainless steel pressure vessel, which is located directly below the hydrate generation and briquetting unit. The two are welded into a smooth transition integral container, a tray-type piston is arranged inside the container, and the tray-type piston is connected to the rotating shaft bracket outside the coating ice shell preparation cavity by a telescopic arm of an external motor. A spring positioning pin is arranged in the middle and lower part of the inner wall of the cavity of the coating ice shell preparation unit, and a liquid passage for installing a precooler is arranged on the side wall, and the liquid passage connects the coating ice shell preparation unit with the deionized water storage tank;

[0008] The ice pack hydrate block storage, transportation and collection unit comprises a conveyor belt, an inclined plate and a cold-insulating ice pack hydrate block collection and storage box. The conveyor belt is arranged below the ice shell preparation unit, and the inclined plate arranged at the end thereof is used to connect the conveyor belt and the cold-insulating hydrate block collection and storage box.

[0009] The constant temperature box is a closed space with a built-in refrigeration fan, and the ice pack hydrate block preparation device is placed inside the constant temperature box as a whole;

[0010] The telescopic arm type rotating shaft structure comprises a bracket with a crossbeam as a rotating shaft and a U-shaped telescopic arm, one end of the U-shaped telescopic arm is connected to the end of the adjacent crossbeam, and the other end is connected to the bottom of the tray type piston. The U-shaped telescopic arm has three sections of telescopicity, and a section of the telescopic arm connected to the bottom of the tray type piston can rotate around the axis;

[0011] The gas supply system includes a high-pressure gas storage bottle and a plunger pump;

[0012] The liquid supply system comprises a methionine solution storage tank, a deionized water storage tank and a liquid pump.

[0013] The upper part of the tray-type piston is processed with a positioning boss and a fin for mechanical sealing, which cooperates and clamps with the protrusion processed on the inner wall of the hydrate formation and compaction cavity to achieve mechanical sealing; the upper side wall of the tray-type piston is processed with a groove, and a V-shaped spring sealing ring is installed inside the groove to achieve double mechanical sealing.

[0014] A method for continuously preparing ice pack hydrate blocks comprises the following steps:

[0015] Step 1: Start the motor to drive the tray-type piston to push up to the groove at the top of the coating ice shell preparation unit, and operate the motor to rotate the tray-type piston horizontally until the fins and the protrusions of the inner wall of the cavity just touch each other, so as to complete the mechanical sealing of the hydrate generation and compaction unit; start the motor to pull the screen-type piston up to the top of the hydrate generation and compaction unit; regulate the refrigeration fan built in the constant temperature box to reduce the temperature inside the constant temperature box to the working temperature;

[0016] Step 2: introducing carbon dioxide gas and methionine solution into the hydrate generation and compaction unit through a gas supply system and a liquid supply system. After the carbon dioxide gas is injected, the V-shaped spring gasket arranged on the side wall of the tray-type piston will expand under the action of the gas pressure, thereby strengthening the mechanical sealing effect between the tray-type piston and the inner wall of the hydrate generation and compaction cavity; standing for a certain period of time until a small amount of hydrate appears inside the cavity of the hydrate generation and briquetting unit; operating the motor to drive the screen-type piston inside the cavity of the hydrate generation and briquetting unit to reciprocate in the vertical direction, and using the screen piston to separate the flocculent hydrate from the unreacted residual water, and the dispersed and loose flocculent hydrate is compacted on the tray-type piston;

[0017] Step 3: With the intermittent injection of methionine solution and carbon dioxide gas, the amount of hydrate generated in the hydrate generation and compaction unit increases, and the upward movement stroke of the screen-type piston gradually decreases. When the displacement sensor on the side wall of the hydrate generation and compaction unit senses that the height of the compacted solid hydrate has reached the sensor position, it indicates that the compaction process has ended, and the compacted block hydrate is obtained;

[0018] Step 4: Set the temperature of the constant temperature box to -20°C. After a period of stabilization, exhaust all the unreacted residual gas from the exhaust port on the side wall of the cavity of the hydrate formation and compaction unit; rotate the tray-type piston horizontally through the motor until the fin and the protrusion on the inner wall of the cavity are just out of the sealing position, and pull the tray-type piston vertically down to the positioning pin in the coated ice shell preparation unit. The positioning boss provided on the upper part of the tray-type piston can prevent excessive displacement of the hydrate block during the pulling process. Inject precooled water into the cavity of the coated ice shell preparation unit through the liquid passage connected to the upper side wall of the coated ice shell preparation unit. Stop when the liquid level is just flush with the connection between the two cavities, and let it stand for 10 hours to complete the preliminary preparation of the ice shell;

[0019] Step 5: After the preliminary preparation of the ice shell is completed, the rotating shaft bracket is driven by the motor to turn the entire device vertically by 180°, and the telescopic arm is operated to move the tray-type piston horizontally until it is completely separated from the coated ice shell preparation cavity, and pre-cooled water is injected into the interior from the injection port at the open port of the cavity adjacent to the coated ice shell preparation unit until the liquid level is flush with the cavity end face of the coated ice shell preparation unit, and the whole ice shell preparation is completed after standing for 10 hours in an environment of -20°C;

[0020] Step 6: After the preparation of the ice pack hydrate sample block is completed, the telescopic arm is operated to return the tray-type piston to the position just aligned with the cavity port of the coated ice shell preparation unit after horizontal displacement, and is positioned in the vertical direction to a position that can contact the ice pack hydrate sample block, and the rotating shaft bracket is started to vertically flip the entire device 180° back to the initial state. The interior of the cavity of the coated ice shell preparation unit is coated with a fluorocarbon hydrophobic coating to ensure that the prepared ice pack hydrate sample block will not be tightly frozen on the inner wall of the cavity of the coated ice shell preparation unit. The telescopic arm is operated to drive the tray-type piston that holds the sample block to move vertically downward until it contacts the material conveyor belt, and the telescopic arm directly connected to the tray-type piston is shortened to the shortest, and the tray-type piston is moved out horizontally, so that the ice pack hydrate sample block falls relatively smoothly on the material conveyor belt, and the ice pack hydrate sample block is collected into the cold-keeping hydrate block collection and storage box through the material conveyor belt, completing the standardized preparation and preservation of the sample.

[0021] Beneficial effects of the present invention:

[0022] (1) It is more in line with the low-cost requirements in practical engineering applications. With the help of the sub-zero low temperature environment in the permafrost zone and the gas diffusion inhibition effect of the outer ice shell, the storage conditions of hydrates can be significantly improved. Samples can be buried in large quantities in the permafrost layer, achieving long-term stable and large-capacity geological carbon storage.

[0023] (2) The device adopts an integrated design, which can continuously complete the hydrate generation, compaction and ice shell coating. The operation process is simple and the sample size is regular and controllable.

[0024] (3) It can make full use of the natural environmental conditions of permafrost areas, with a wide application area, and organically promote the self-protection effect of hydrates to the engineering application stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of an ice pack hydrate block preparation device;

[0026] Figure 2 It is a three-dimensional diagram of a tray-type piston;

[0027] Figure 3 It is a three-dimensional cross-sectional view of a local cavity;

[0028] Figure 4 It is a V-shaped spring seal.

[0029] In the figure: 1-motor, 2-cold-insulated ice pack hydrate block collection and storage box, 3-inclined plate, 4-telescopic arm type rotating shaft structure, 5-coated ice shell preparation cavity, 6-locating pin, 7-tray type piston, 8-V-type spring sealing ring, 9-displacement sensor, 10-exhaust port, 11-hydrate generation and compaction cavity, 12-screen type piston, 13-constant temperature box, 14-vacuum pump interface, 15-gas injection port, 16-first liquid injection port, 17-locating boss, 18-second liquid injection port, 19-precooler, 20-third liquid injection port, 21-rotating shaft bracket, 22-material conveyor belt, 23-liquid storage tank. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0031] An ice pack hydrate block preparation device includes three main parts: a hydrate generation and briquetting unit, an ice shell coating preparation unit, and an ice pack hydrate block storage, transportation, and collection unit. First, push the tray-type piston 7 to the top of the ice shell coating preparation cavity 5 until the tray-type piston 7 slides into the groove at the bottom of the hydrate generation and compaction cavity 11, start the motor 1 to operate the rotating shaft structure 4 to drive the tray-type piston 7 to rotate horizontally 90° until the fins on the upper end of the tray-type piston 7 abut against the protrusions on the inner wall of the hydrate generation and compaction cavity 11, and use the mechanical structure to clamp and seal the tray-type piston 7 and the hydrate generation and compaction cavity 11; open the valve of the vacuum pump interface 14, start the vacuum pump to extract the impurity gas in the hydrate generation and compaction cavity 11, and at the same time adjust the refrigeration device connected to the constant temperature box 13 to reduce the temperature in the hydrate generation and compaction cavity 11 to 1°C; open the hydrate The gas injection port on the side wall of the formation and compaction cavity 11 is used to inject carbon dioxide gas into the cavity 11 through a plunger pump until the pressure reaches 3.5 MPa, that is, to ensure that the temperature and pressure in the cavity 11 meet the hydrate formation conditions. At this time, the V-shaped spring seal ring 8 is further expanded under the action of the air pressure, and the sealing effect of the cavity 11 is enhanced; then the first liquid injection port 16 on the side wall of the hydrate formation and compaction cavity 11 is opened, and about 200 ml of methionine solution is injected into the cavity 11 through a liquid pump. After standing for a certain period of time to wait for hydrate formation, the motor 1 connected to the screen piston 12 is operated to drive the screen piston 12 to reciprocate in the vertical direction to separate the flocculent hydrate formed in the cavity 11 from the unreacted residual hydrate. Water-solid-liquid separation, under the reciprocating action of the piston 12, the hydrate is compacted into a cylindrical shape, and then the above process is repeated multiple times in the hydrate formation and compaction chamber 11 according to the operation sequence of gas injection, liquid injection and cake pressing, until the sensor 9 set on the side wall of the hydrate formation and compaction chamber 11 senses that the height of the compacted solid hydrate block is higher than the lower edge of the sensor 9, stop repeating the above process, complete the hydrate block preparation and compaction work, start the motor 1 to pull the screen piston 12 to the top position of the cavity 11; adjust the temperature of the constant temperature box 13 to -20°C, and after stabilizing at this temperature for about 4 hours, open the exhaust port 10 valve on the side wall of the hydrate formation and briquetting unit 11, and press the cavity 11 pressure Release to normal pressure; start the motor 1 to rotate the tray-type piston 7 horizontally by 90° to the initial free position, release its seal, and then operate the telescopic arm 4 through the motor 1 to pull the tray-type piston 7 down to the position of the positioning pin 6 in the coating ice shell preparation area 5. Because the tray-type piston 7 is provided with a positioning boss 17, it can be ensured that during the pulling-down process of the piston 7, the compacted cylindrical hydrate block will not be significantly displaced; inject deionized water precooled by the precooler 19 into the cavity from the injection port 18 on the side wall of the coating ice shell preparation unit 5 until the precooled water completely fills the coating ice shell preparation unit 5 above the tray-type piston 7; let the whole device stand for 10 hours in an environment of -20°C to wait for the initial freezing of the ice shell;The rotating shaft bracket 21 is operated by the motor 1 to make the whole device flip 180° in the vertical direction, and the motor 1 is started to rotate the tray-type piston 7 horizontally by 90° to facilitate separation from the frozen sample block, and then the tray-type piston 7 is pulled upward, and the telescopic arm 4 connected thereto is started to move the piston 7 toward the bracket 21 until the piston 7 is completely separated from the port of the ice shell preparation cavity 5; the water in the liquid storage tank 23 is cooled by the precooler 19, and then injected into the cavity 5 from the liquid injection port 20 on the side wall of the ice shell preparation unit 5 until the ice shell preparation cavity 5 is filled with precooled water, and the whole device is kept at -20°C for 10 hours to wait for the complete freezing of the whole ice shell; after complete freezing, the tray-type piston 7 is driven by the telescopic arm rotating shaft structure 4 to move back through vertical and horizontal displacements. Move to the position just in contact with the sample block, start the rotating shaft support 21 to flip the entire device 180° in the vertical direction and return to the initial position; inject a certain pressure of carbon dioxide gas from the gas injection port 15 on the side wall of the hydrate generation and compaction unit 11, so that the ice pack hydrate sample is separated from the ice shell preparation cavity 5 under the action of the pressure difference, operate the telescopic arm 4 connected to the tray-type piston 7, so that the tray-type piston 7 is horizontally and vertically displaced until the piston 7 contacts the material conveyor belt 22, and then move the tray-type piston 7 horizontally to make the ice pack hydrate sample block fall relatively stably on the material conveyor belt 22, start the conveyor belt 22 to slide the prepared sample block through the inclined plate 3 into the cold-keeping sample collection container 2, and then start the next cycle to complete the automatic continuous preparation and storage of ice pack hydrate sample blocks. ;

Claims

1. An ice pack hydrate block preparation device, characterized in that: The ice pack hydrate block preparation device comprises a hydrate generation and briquetting unit, an ice shell preparation unit, an ice pack hydrate block storage, transportation and collection unit, a constant temperature box, a gas supply system, a liquid supply system and a telescopic arm type rotating shaft structure; The hydrate generation and briquetting unit is a cylindrical stainless steel pressure vessel, which is located in the upper area of ​​the ice pack hydrate block preparation device, and is provided with a screen piston with a screen aperture of 200 meshes, and the piston push rod is connected to the motor. The cavity side wall of the hydrate generation and briquetting unit is provided with a gas passage and a liquid passage, the gas passage is connected to the hydrate generation and compaction unit and the high-pressure gas storage cylinder, the liquid passage is connected to the hydrate generation and compaction unit and the methionine solution storage tank, and the cavity side wall of the hydrate generation and briquetting unit is provided with a fixed site, which is connected to the rotating shaft support; The coating ice shell preparation unit is a cylindrical stainless steel pressure vessel, which is located directly below the hydrate generation and briquetting unit. The two are welded into a smooth transition integral container, a tray-type piston is arranged inside the container, and the tray-type piston is connected to the rotating shaft bracket outside the coating ice shell preparation cavity by a telescopic arm of an external motor. A spring positioning pin is arranged in the middle and lower part of the inner wall of the cavity of the coating ice shell preparation unit, and a liquid passage for installing a precooler is arranged on the side wall, and the liquid passage connects the coating ice shell preparation unit with the deionized water storage tank; The ice pack hydrate block storage, transportation and collection unit comprises a conveyor belt, an inclined plate and a cold-insulating ice pack hydrate block collection and storage box. The conveyor belt is arranged below the ice shell preparation unit, and the inclined plate arranged at the end thereof is used to connect the conveyor belt and the cold-insulating hydrate block collection and storage box. The constant temperature box is a closed space with a built-in refrigeration fan, and the ice pack hydrate block preparation device is placed inside the constant temperature box as a whole; The telescopic arm type rotating shaft structure comprises a bracket with a crossbeam as a rotating shaft and a U-shaped telescopic arm, one end of the U-shaped telescopic arm is connected to the end of the crossbeam, and the other end is connected to the bottom of the tray-type piston. The U-shaped telescopic arm has three-stage telescopicity, and a section of the telescopic arm connected to the bottom of the tray-type piston can rotate around the axis; The gas supply system includes a high-pressure gas storage bottle and a plunger pump; The liquid supply system comprises a methionine solution storage tank, a deionized water storage tank and a liquid pump.

2. The ice pack hydrate block preparation device according to claim 1, characterized in that: The upper part of the tray-type piston is processed with a positioning boss and a fin for mechanical sealing, which cooperates and clamps with the protrusion processed on the inner wall of the hydrate formation and compaction cavity to achieve mechanical sealing; the upper side wall of the tray-type piston is processed with a groove, and a V-shaped spring sealing ring is installed inside the groove to achieve double mechanical sealing.

3. A method for continuously preparing ice pack hydrate blocks, characterized in that: The steps include: Step 1: Start the motor to drive the tray-type piston to push up to the groove on the top of the coating ice shell preparation unit, and operate the motor to rotate the tray-type piston horizontally until the fins and the protrusions on the inner wall of the cavity just touch each other, so as to complete the mechanical sealing work of the hydrate generation and compaction unit; Start the motor to pull the screen piston up to the top of the hydrate generation and compaction unit; adjust the refrigeration fan built into the constant temperature box to reduce the temperature inside the constant temperature box to the working temperature; Step 2: introducing carbon dioxide gas and methionine solution into the hydrate generation and compaction unit through a gas supply system and a liquid supply system. After the carbon dioxide gas is injected, the V-shaped spring gasket arranged on the side wall of the tray-type piston will expand under the action of the gas pressure, thereby strengthening the mechanical sealing effect between the tray-type piston and the inner wall of the hydrate generation and compaction cavity; standing for a certain period of time until a small amount of hydrate appears inside the cavity of the hydrate generation and briquetting unit; operating the motor to drive the screen-type piston inside the cavity of the hydrate generation and briquetting unit to reciprocate in the vertical direction, and using the screen piston to separate the flocculent hydrate from the unreacted residual water, and the dispersed and loose flocculent hydrate is compacted on the tray-type piston; Step 3: With the intermittent injection of methionine solution and carbon dioxide gas, the amount of hydrate generated in the hydrate generation and compaction unit increases, and the upward movement stroke of the screen-type piston gradually decreases. When the displacement sensor on the side wall of the hydrate generation and compaction unit senses that the height of the compacted solid hydrate has reached the sensor position, it indicates that the compaction process has ended, and the compacted block hydrate is obtained; Step 4: Set the temperature of the constant temperature box to -20°C. After a period of stabilization, exhaust all the unreacted residual gas from the exhaust port on the side wall of the cavity of the hydrate formation and compaction unit; rotate the tray-type piston horizontally through the motor until the fin and the protrusion on the inner wall of the cavity are just out of the sealing position, and pull the tray-type piston vertically down to the positioning pin in the coated ice shell preparation unit. The positioning boss provided on the upper part of the tray-type piston can prevent excessive displacement of the hydrate block during the pulling process. Inject precooled water into the cavity of the coated ice shell preparation unit through the liquid passage connected to the upper side wall of the coated ice shell preparation unit. Stop when the liquid level is just flush with the connection between the two cavities, and let it stand for 10 hours to complete the preliminary preparation of the ice shell; Step 5: After the preliminary preparation of the ice shell is completed, the rotating shaft bracket is driven by the motor to turn the entire device vertically by 180°, and the telescopic arm is operated to move the tray-type piston horizontally until it is completely separated from the coated ice shell preparation cavity, and pre-cooled water is injected into the interior from the injection port at the open port of the cavity adjacent to the coated ice shell preparation unit until the liquid level is flush with the cavity end face of the coated ice shell preparation unit, and the whole ice shell preparation is completed after standing for 10 hours in an environment of -20°C; Step 6: After the preparation of the ice pack hydrate sample block is completed, the telescopic arm is operated to return the tray-type piston to the position just aligned with the cavity port of the coated ice shell preparation unit after horizontal displacement, and is positioned in the vertical direction to a position that can contact the ice pack hydrate sample block, and the rotating shaft bracket is started to vertically flip the entire device 180° back to the initial state. The interior of the cavity of the coated ice shell preparation unit is coated with a fluorocarbon hydrophobic coating to ensure that the prepared ice pack hydrate sample block will not be tightly frozen on the inner wall of the cavity of the coated ice shell preparation unit. The telescopic arm is operated to drive the tray-type piston that holds the sample block to move vertically downward until it contacts the material conveyor belt, and the telescopic arm directly connected to the tray-type piston is shortened to the shortest, and the tray-type piston is moved out horizontally, so that the ice pack hydrate sample block falls relatively smoothly on the material conveyor belt, and the ice pack hydrate sample block is collected into the cold-keeping hydrate block collection and storage box through the material conveyor belt, completing the standardized preparation and preservation of the sample.

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