Multi-channel miniature high-pressure device and method capable of observing formation of gas hydrate

Abstract

The invention relates to the technical field of gas hydrates, in particular to a multi-channel miniature high-pressure device and method capable of observing formation of gas hydrates. According to the specific technical scheme, the device comprises a high-pressure optical pool, a plurality of capillary quartz tubes are packaged in the high-pressure optical pool, and the tail ends of the capillary quartz tubes are located in a temperature control cooling table; the temperature control cooling table is connected with the liquid nitrogen tank and the temperature controller; the high-pressure optical pool is placed on the three-axis balancing table, a real-time display system is arranged on the outer side of the high-pressure optical pool, and the high-pressure optical pool is connected with a stable air inlet system through a flange type connector. According to the invention, the generation process of the micro-scale gas hydrate can be researched under the conditions of high pressure and low temperature, multiple groups of parallel experiments can be carried out simultaneously, and the generation morphology and the dynamic change process of the gas hydrate in the multichannel capillary quartz tube can be observed on line in real time; and the influence of random nucleation generation of the hydrate can be reduced while the operation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas hydrates, and in particular to a multi-channel micro high-pressure device and method for observing the formation of gas hydrates. Background Art

[0002] By gas molecules (such as CH 4 , CO 2 A crystalline solid compound formed by gas hydrates (such as carbon hydrates) and water molecules under low temperature and high pressure. It has a cage-like structure similar to ice and is also called a cage-type hydrate. Gas hydrates have attracted extensive attention from researchers due to their high gas storage efficiency. The growth law and kinetic characteristics of hydrates can be revealed by studying the hydrate morphology.

[0003] At present, there are a large number of gas hydrate observation experiments, most of which only observe the hydrate formation and decomposition process on a macroscopic scale and cannot reflect a more microscopic scale. In addition, optical microscopes are used to study the formation of hydrates, but the nucleation and growth of hydrates have a certain randomness, and a single experiment cannot reflect the growth law of hydrates. In view of the current lack of microscopic observation methods for gas hydrates, a multi-channel micro high-pressure device and method for observing the formation of gas hydrates has been developed, which has important practical significance for studying the microscopic formation dynamics of hydrates. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a multi-channel micro high-pressure device and method for observing the formation of gas hydrates.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] The present invention discloses a multi-channel micro high-pressure device capable of observing the formation of gas hydrates, comprising a high-pressure optical cell, wherein a plurality of capillary quartz tubes are encapsulated in the high-pressure optical cell, and the ends of the capillary quartz tubes are located inside a temperature-controlled cold stage; the temperature-controlled cold stage is connected to a liquid nitrogen tank and a temperature controller;

[0007] The high-pressure optical cell is placed on a three-axis balancing platform, a real-time display system is arranged on the outside of the high-pressure optical cell, and a stable air intake system is connected to the high-pressure optical cell via a flange joint.

[0008] Preferably, the real-time display system includes several industrial microscope cameras, and the several industrial microscope cameras are connected to a computer.

[0009] Preferably, the stable air intake system includes a gas buffer tank, which is respectively connected to a gas cylinder and a vacuum pump through pipelines, and the gas buffer tank is connected to a high-pressure optical cell through a pipeline. A secondary pressure reducing valve is provided on the pipeline connecting the gas buffer tank and the high-pressure optical cell, and a pressure sensor is provided on the pipeline connecting the high-pressure optical cell and the secondary pressure reducing valve.

[0010] Preferably, the pressure sensor is connected to a data collector, and the data collector is connected to a computer.

[0011] Preferably, the pipeline connecting the gas cylinder and the vacuum pump to the gas buffer tank is respectively provided with a stop valve V2 and a stop valve V1, the pipeline connecting the gas buffer tank and the high-pressure optical cell is sequentially provided with a stop valve V3, a three-way drain valve V4 and a three-way connecting pipeline valve V5, and the secondary pressure reducing valve is arranged on the pipeline between the stop valve V3 and the three-way connecting pipeline valve V5.

[0012] Preferably, the pressure of the gas buffer tank is higher than the pressure of the capillary quartz tube in the high-pressure optical cell, and the gas pressure in the capillary quartz tube in the high-pressure optical cell is controlled and kept stable by the secondary pressure reducing valve.

[0013] Accordingly, a method for using a multi-channel micro high-pressure device for observing gas hydrate formation comprises the following steps:

[0014] (1) Connect one end of the capillary quartz tube containing the solution to be tested to the interface of the high-pressure optical cell and connect it to the pipeline through a flange joint, then place the high-pressure optical cell on a three-axis balance table, adjust the three-axis balance table until the capillary quartz tube in the high-pressure optical cell is aligned with the port of the temperature-controlled cold stage, and insert the welded end of the capillary quartz tube into the interior of the temperature-controlled cold stage and fix it;

[0015] (2) Keep the vacuum pump and the gas buffer tank connected, keep the gas buffer tank connected to the high-pressure optical reaction cell, start the vacuum pump to evacuate, and observe the value of the pressure sensor collected by the data acquisition device on the computer;

[0016] (3) Keep the gas cylinder and the gas buffer tank connected, inject a gas volume higher than the pressure required for the experiment into the gas buffer tank, open the stop valve V3 on the pipeline connecting the secondary pressure reducing valve and the gas buffer tank, and adjust the pressure to the required experimental pressure through the secondary pressure reducing valve;

[0017] (4) The temperature of the solution to be tested in the capillary quartz tube in the high-pressure optical cell is controlled by liquid nitrogen in the liquid nitrogen tank and a temperature-controlled cold stage until the temperature required for the experiment is reached;

[0018] (5) Turn on the industrial microscope camera to record the test solution in the capillary quartz tube in the high-pressure optical cell and record it on a computer.

[0019] The present invention has the following beneficial effects:

[0020] 1. The present invention saves reaction raw materials and is resistant to high pressure, and can realize the formation of gas hydrates under high pressure and low temperature conditions; at the same time, the two-phase interface in the capillary quartz tube can be observed to capture the hydrate formation process at the gas-liquid interface.

[0021] 2. In the present invention, a plurality of capillary quartz tubes are arranged in the high-pressure optical cell, so that multiple groups of parallel experiments can be carried out at the same time, shortening the cycle and reducing the experimental randomness caused by the nucleation and growth of gas hydrates; and the flange sealing method is adopted at the high-pressure optical cell and the pipeline, which can effectively reduce the occurrence of gas leakage;

[0022] 3. The present invention can utilize a real-time display system and a stable air intake system to realize the formation of hydrates at constant temperature and pressure and the decomposition at elevated temperature, and obtain the crystal morphology and microscopic kinetic parameters of hydrate formation and decomposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of a multi-channel micro high-pressure device for observing gas hydrate formation;

[0024] Figure 2 The diagrams are schematic diagrams of the two end faces of the flange joint; the left diagram is a schematic diagram of the end of the flange joint connected to the pipeline, and the right diagram is a schematic diagram of the end of the flange joint connected to the high-pressure optical cell. The outer circle has a high-pressure sealing ring, and the four black circles are encapsulated capillary quartz tubes.

[0025] Figure 3 It is a schematic diagram of the end of the high pressure optical cell corresponding to the temperature controlled cold stage;

[0026] Figure 4 This is a diagram of the settings of the first, second, third and fourth industrial microscope cameras;

[0027] In the figure: gas cylinder 1, vacuum pump 2, gas buffer tank 3, three-axis balance table 4, liquid nitrogen tank 5, temperature controller 6, temperature control cold stage 7, high-pressure optical cell 8, data acquisition device 9, computer 10, flange joint 11, stop valve V1, stop valve V2, stop valve V3, three-way drain valve V4, three-way connecting pipeline valve V5, first industrial microscope camera 121, second industrial microscope camera 122, third industrial microscope camera 123, fourth industrial microscope 124, secondary pressure reducing valve 131. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0030] refer to Figure 1-Figure 4 The present invention discloses a multi-channel micro high-pressure device for observing the formation of gas hydrates, comprising a high-pressure optical cell 8, wherein a plurality of capillary quartz tubes are encapsulated in the high-pressure optical cell 8 and can withstand a pressure of 20 MPa; the ends of the capillary quartz tubes are inserted into the interior of a temperature-controlled cold stage 7, and one end of the capillary quartz tubes inserted into the interior of the temperature-controlled cold stage 7 is purged with a dry airflow to prevent water mist from forming on the surface.

[0031] The temperature-controlled cold stage 7 is connected to the liquid nitrogen tank 5 and the temperature controller 6. The temperature-controlled cold stage 7 controls the experimental temperature of the end of the capillary quartz tube containing the solution to be tested in the high-pressure optical cell 8, with an accuracy of ±0.1K, and provides a stable working temperature for the solution to be tested at the end of the capillary quartz tube; the high-pressure optical cell 8 is placed on the three-axis balance table 4, which provides support for it. A real-time display system is provided on the outside of the high-pressure optical cell 8, which can synchronously observe the formation of gas hydrates in the capillary quartz tube in the high-pressure optical cell 8. The high-pressure optical cell 8 is connected to a stable air intake system through a flange joint 11.

[0032] Furthermore, the real-time display system includes a plurality of industrial microscope cameras, which are connected to the computer 10 and can obtain the growth of gas hydrates in the capillary quartz tube in the high-pressure optical cell in real time online.

[0033] Furthermore, the stable air intake system includes a gas buffer tank 3, which is connected to the gas cylinder 1 and the vacuum pump 2 through pipelines, and is connected to the high-pressure optical cell 8 (specifically connected to the flange joint 11) through pipelines. A secondary pressure reducing valve 131 is provided on the pipeline connecting the gas buffer tank 3 and the high-pressure optical cell 8 (or the flange joint 11), and a pressure sensor is provided on the pipeline connecting the high-pressure optical cell 8 and the secondary pressure reducing valve 131. The pressure sensor is connected to the data acquisition device 9, and the data acquisition device 9 is connected to the computer 10, and data can be collected every 10 seconds. A stop valve V2 is provided on the pipeline connecting the gas cylinder 1 to the gas buffer tank 3, and a stop valve V1 is provided on the pipeline connecting the vacuum pump 2 to the gas buffer tank 3.

[0034] Furthermore, a stop valve V3, a secondary pressure reducing valve 131, a three-way drain valve V4 and a three-way connecting pipeline valve V5 are sequentially arranged on the pipeline connecting the gas buffer tank 3 and the high-pressure optical cell 8, and the pressure sensor is arranged on the pipeline connecting the three-way connecting pipeline valve V5 and the high-pressure optical cell 8.

[0035] Furthermore, the pressure of the gas buffer tank 3 is higher than the pressure of the capillary quartz tube in the high-pressure optical cell 8 , and the gas pressure in the capillary quartz tube in the high-pressure optical cell 8 is controlled and kept stable by the secondary pressure reducing valve 131 .

[0036] As one of the implementation modes, the high-pressure optical cell 8 encapsulates 1 to 4 capillary quartz tubes (not limited to 4), taking 4 as an example, one end of the 4 capillary quartz tubes encapsulated in the high-pressure optical cell 8 is welded with an oxyhydrogen flame and can be directly inserted into the temperature-controlled cold stage 7. The other end of the high-pressure optical cell 8 is connected to its interface through a flange joint 11 and is connected to the pipeline (the pipeline where the stop valve V3 and the secondary pressure reducing valve 131 are located), and is sealed by a high-pressure sealing ring to prevent air leakage. The temperature-controlled cold stage 7 is provided with a port suitable for the capillary quartz tube to pass through, and a metal platform for fixing the capillary quartz tube is provided inside the temperature-controlled cold stage 7, and the metal platform is provided with a groove suitable for accommodating the capillary quartz tube. Reference Figure 3 In this embodiment, four industrial microscope cameras can be provided, namely a first industrial microscope 121, a second industrial microscope 122, a third industrial microscope 123, and a fourth industrial microscope 124. The first industrial microscope 121 and the second industrial microscope 122 are located at the top, and the third industrial microscope 123 and the fourth industrial microscope 124 are located at the bottom.

[0037] The present invention discloses a method for observing the formation of gas hydrates, which can study the formation of microscopic gas hydrates under high pressure and low temperature conditions, use the imaging function of the real-time display system to capture the changes in the hydrate morphology in real time, and observe the formation process of multiple groups of hydrates in real time. Specifically, it includes the following steps:

[0038] (1) Prepare a capillary quartz tube: the inner diameter of the capillary quartz tube can be 0.9 μm and the outer diameter can be 1.1 μm; one end of four (not limited to four) capillary quartz tubes is sealed with hydrogen-oxygen flame, and the solution to be tested in the capillary quartz tube is rotated to the bottom of the capillary quartz tube by a high-speed centrifuge, and the other end of the capillary quartz tube (not welded end) is connected to the flange joint 11 through the interface of the high-pressure optical cell 8 and connected to the pipeline; then the high-pressure optical cell 8 is placed on the three-axis balance table 4, and the three-axis balance table 4 is adjusted until the capillary quartz tube in the high-pressure optical cell 8 is aligned with the port of the temperature-controlled cold stage 7, and one end of the capillary quartz tube (welded end) is inserted into the interior of the temperature-controlled cold stage 7 and fixed in the groove on the metal table inside the temperature-controlled cold stage 7.

[0039] (2) Vacuuming: Keep the vacuum pump 2 and the gas buffer tank 3 connected, keep the gas buffer tank 3 and the high-pressure optical reaction cell 8 connected, turn on the vacuum pump 2 to perform vacuuming, and observe the value of the pressure sensor collected by the data acquisition device 9 on the computer 10.

[0040] The specific adjustment process is as follows: close the stop valve V2 between the gas cylinder 1 and the gas buffer tank 3, open the stop valve V1 between the vacuum pump 2 and the gas buffer tank 3, open the stop valve V3 between the gas buffer tank 3 and the secondary pressure reducing valve 131 and slightly open the secondary pressure reducing valve 131, open the secondary pressure reducing valve 131 and the three-way connecting pipeline valve V5 on the pipeline connected to the high-pressure optical reaction pool 8, close the three-way drain valve V4, so that the pipeline from the gas buffer tank to the high-pressure optical pool remains connected, start the vacuum pump 2 to evacuate, and observe the pressure sensor data collected by the data acquisition device 9 on the computer 10. After evacuating for 5 minutes, close the stop valve V1, observe the pressure sensor reading and confirm that the pipeline is well sealed.

[0041] (3) Injecting gas: Close the stop valve V3, open the stop valve V2, keep the gas cylinder 1 and the gas buffer tank 3 connected, and inject a gas volume higher than the pressure required for the experiment into the gas buffer tank 3. Then close the stop valve V2, open the stop valve V3, and adjust the pressure to the required experimental pressure, such as 2MPa, 2.5MPa or 3MPa, through the secondary pressure reducing valve 131.

[0042] (4) Temperature control: Add an appropriate amount of liquid nitrogen into the liquid nitrogen tank 5, start the temperature control cold stage 7, and control the temperature of the solution to be tested in the capillary quartz tube in the high-pressure optical cell 8 through the liquid nitrogen in the liquid nitrogen tank 5 and the temperature control cold stage 7. Adjust the temperature controller 6 until the temperature required for the experiment is reached, such as 275.2K.

[0043] (5) Testing: Turn on the industrial microscope camera to record and observe the gas-liquid interface of the solution to be tested in the capillary quartz tube in the high-pressure optical cell 8, and record it through the computer 10.

[0044] (6) End of the experiment: close the stop valve V3, open the three-way drain valve V4 of the pipeline connecting the high-pressure optical cell 8 and the secondary pressure reducing valve 131, and vent the gas in the entire device to restore the pressure of the entire device to normal pressure. Based on the acquired data, analyze key indicators such as the surface tension of the solution, the morphology of hydrate crystal formation, and the growth rate of hydrate crystals under different experimental conditions.

[0045] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0046] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A multi-channel micro high-pressure device capable of observing the formation of gas hydrates, characterized in that: It comprises a high-pressure optical cell (8), wherein a plurality of capillary quartz tubes are encapsulated in the high-pressure optical cell (8), and the ends of the capillary quartz tubes are located inside a temperature-controlled cold stage (7); the temperature-controlled cold stage (7) is connected to a liquid nitrogen tank (5) and a temperature controller (6); The high-pressure optical cell (8) is placed on a three-axis balancing platform (4), a real-time display system is arranged on the outside of the high-pressure optical cell (8), and a stable air intake system is connected to the high-pressure optical cell (8) via a flange joint (11).

2. A multi-channel micro high-pressure device capable of observing gas hydrate formation according to claim 1, characterized in that: The real-time display system comprises a plurality of industrial microscope cameras, and the plurality of industrial microscope cameras are connected to a computer (10).

3. A multi-channel micro high-pressure device capable of observing gas hydrate formation according to claim 2, characterized in that: The stable air intake system comprises a gas buffer tank (3), the gas buffer tank (3) being connected to a gas cylinder (1) and a vacuum pump (2) respectively through pipelines, the gas buffer tank (3) being connected to a high-pressure optical cell (8) through pipelines, a secondary pressure reducing valve (131) being provided on the pipeline connecting the gas buffer tank (3) and the high-pressure optical cell (8), and a pressure sensor being provided on the pipeline connecting the high-pressure optical cell (8) and the secondary pressure reducing valve (131).

4. A multi-channel micro high-pressure device capable of observing gas hydrate formation according to claim 3, characterized in that: The pressure sensor is connected to a data collector (9), and the data collector (9) is connected to a computer (10).

5. The multi-channel micro high-pressure device capable of observing the formation of gas hydrates according to claim 3, characterized in that: The pipeline connecting the gas cylinder (1) and the vacuum pump (2) with the gas buffer tank (3) is provided with a stop valve V2 and a stop valve V1 respectively; the pipeline connecting the gas buffer tank (3) and the high-pressure optical cell (8) is provided with a stop valve V3, a three-way drain valve V4 and a three-way connecting pipeline valve V5 in sequence; the secondary pressure reducing valve (131) is provided on the pipeline between the stop valve V3 and the three-way connecting pipeline valve V5.

6. A multi-channel micro high-pressure device capable of observing gas hydrate formation according to claim 5, characterized in that: The pressure of the gas buffer tank (3) is higher than the pressure of the capillary quartz tube in the high-pressure optical cell (8), and the gas pressure in the capillary quartz tube in the high-pressure optical cell (8) is controlled and kept stable by the secondary pressure reducing valve (131).

7. A method for using the multi-channel micro high-pressure device for observing gas hydrate formation according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) connecting one end of a capillary quartz tube containing a solution to be tested to an interface of a high-pressure optical cell (8) and connecting it to a pipeline via a flange joint (11), then placing the high-pressure optical cell (8) on a three-axis balancing table (4), adjusting the three-axis balancing table (4) until the capillary quartz tube in the high-pressure optical cell (8) is aligned with the port of a temperature-controlled cold stage (7), and inserting one end of the capillary quartz tube into the temperature-controlled cold stage (7) and fixing it; (2) maintaining a connection between the vacuum pump (2) and the gas buffer tank (3), maintaining a connection between the gas buffer tank (3) and the high-pressure optical reaction cell (8), turning on the vacuum pump (2) to evacuate the air, and observing the value of the pressure sensor collected by the data acquisition device (9) on the computer (10); (3) Keeping the gas cylinder (1) and the gas buffer tank (3) connected, injecting a gas volume higher than the pressure required for the experiment into the gas buffer tank (3), opening the stop valve V3 on the pipeline connecting the secondary pressure reducing valve (131) and the gas buffer tank (3), and adjusting the pressure to the required experimental pressure through the secondary pressure reducing valve (131); (4) controlling the temperature of the solution to be tested in the capillary quartz tube in the high-pressure optical cell (8) by using the liquid nitrogen in the liquid nitrogen tank (5) and the temperature-controlled cold stage (7) until the temperature reaches the required temperature for the experiment; (5) Turn on the industrial microscope camera to record and observe the solution to be tested in the capillary quartz tube in the high-pressure optical cell (8), and record it through the computer (10).

Images