Device for optical observation and structural analysis of hydrate crystal growth

Abstract

The invention discloses a device for optical observation and structural analysis of hydrate crystal growth, and belongs to the technical field of energy scientific research instruments. The device comprises a capillary reaction kettle, a gas injection system, a detection system, a temperature control system and a data acquisition system. And the capillary reaction kettle is internally provided with a high-pressure capillary. One end of the capillary reaction kettle is connected with a gas injection system and is jointly controlled by a gas cylinder, a pressure regulating meter and a high-pressure plunger pump; a Raman observation system is arranged at a position corresponding to a visible window at the top end of the capillary reaction kettle and is used for observing and recording a hydrate crystal structure, and under a non-Raman test condition, the system can be equally replaced by a microscopic imaging system and is used for monitoring the growth form change of the hydrate crystal in real time. The internal temperature of the capillary reaction kettle is controlled by the upper cover, the main body and the internal low-temperature circulating cavity. The device can realize Raman or optical in-situ observation of full-period change of hydrate crystal growth in the capillary tube.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy research instruments, and particularly relates to a device for optical observation and structural analysis of hydrate crystal growth. Background Art

[0002] Hydrates are a type of cage compounds formed by water molecules and guest molecules through weak intermolecular forces, usually generated under low-temperature and high-pressure conditions. Due to their high gas storage density and clean and environmentally friendly characteristics, in recent years, hydrate technology has made great progress in the research and application in the fields of carbon dioxide emission reduction, cold energy storage, and seawater desalination. However, to further promote the practical application of hydrate technology, in-depth research on hydrate crystal formation and crystal structure is essential.

[0003] The study of hydrate crystals is of great significance for understanding their formation mechanism and kinetic characteristics. The formation process of hydrates mainly involves complex processes such as gas-liquid diffusion and phase transformation. These processes are not only affected by external conditions (such as temperature and pressure), but also closely related to the types of guest molecules, etc. As a typical porous medium, a capillary can effectively simulate the hydrate formation process and study the growth behavior of crystals therein. At the same time, the influence of the confined space in the capillary on hydrate growth has significant research value, and the hydrate crystal morphology and stability can be studied in depth.

[0004] In the study of hydrate crystals, Raman spectroscopy and optical microscopy are two indispensable experimental means. Raman spectroscopy is a non-destructive detection technique based on molecular vibration, which can provide detailed information about molecular structure, chemical bonds, and crystal composition. For example, through Raman spectroscopy, the interaction between water molecules and gas molecules in hydrate crystals can be detected, and the stability, formation kinetics, and phase transformation process of hydrates can be studied. Optical microscopy can directly observe the morphology, size, and growth dynamics of hydrate crystals, providing high-resolution image support for studying the microscopic behavior of hydrates. These two techniques have their own advantages in hydrate research. However, in current experiments, these two techniques usually rely on independent devices, and it is difficult to achieve observation using the same device. In traditional experiments, an optical microscope is mainly used to record the morphological changes of hydrate crystal growth, while a Raman spectrometer is used to analyze molecular structure and composition information. Due to the different working principles and optical designs of the two devices, devices that can simultaneously meet these two functions are relatively rare. This separate experimental method not only increases the complexity of experimental operations, but also limits the real-time joint observation ability of hydrate crystal growth and structural changes, and cannot meet the comprehensive research needs for dynamic processes and local characteristics. Summary of the Invention

[0005] To solve the problems existing in the observations of the prior art, the present invention proposes a device for optical observation and structural analysis of hydrate crystal growth. This device not only has scientific research and teaching value, but also has potential for technical applications, which will be conducive to improving the practical applications and development of hydrate technology in various fields.

[0006] The technical solution adopted by the present invention is as follows: A device for optical observation and structural analysis of hydrate crystal growth, which includes a capillary reactor, a gas injection system, a detection system, a temperature control system, and a data acquisition system;

[0007] The capillary reactor includes a reactor main body and a reactor upper cover, and the reactor upper cover is provided with an upper cover low-temperature circulation cavity;

[0008] On the outer side of the reactor main body, a main body low-temperature circulation cavity is adopted. The interior of the reactor main body includes a transmission area and a capillary fixing area; in the transmission area, the main body driver passes through the side wall of the reactor main body and is connected to the gas injection pipe fixing platform. The gas injection pipe fixing platform is sleeved on one end of the transmission rod, and the other end is fixed on the capillary fixing platform. A spring is sleeved outside the transmission rod; the gas injection pipe is fixed in the gas injection pipe fixing card slot of the gas injection pipe fixing platform through the gas injection pipe fixing pressing piece;

[0009] In the capillary fixing area, the capillary fixing platform and the in-body low-temperature circulation cavity are fixed on the reactor main body. One end of the high-pressure capillary is a sealed end, and the other end is an open end, and the open end is connected to the gas injection pipe;

[0010] At the open end, it is supported by the fixing platform card slot of the capillary fixing platform. At the sealed end, it is pressed in the circulation cavity card slot by the capillary visual pressing piece fixed in the in-body low-temperature circulation cavity. The capillary visual pressing piece is provided with a visual notch for observing the high-pressure capillary;

[0011] When the main body driver moves the gas injection pipe fixing platform, the gas injection pipe moves together with the gas injection pipe fixing platform, so that the high-pressure capillary moves in the fixing platform card slot and the circulation cavity card slot;

[0012] Visual windows for light transmission or observation are provided on both the reactor upper cover and the reactor main body, and the high-pressure capillary at the visual notch is in the light transmission or observation area of the visual window;

[0013] The gas injection system is connected to the high-pressure capillary of the capillary reactor;

[0014] The detection system is used for Raman detection or optical detection of the capillary reactor;

[0015] The temperature control system is communicated with the upper cover low-temperature circulation cavity, the main body low-temperature circulation cavity, and the in-body low-temperature circulation cavity of the capillary reactor.

[0016] In the temperature control system, the low-temperature circulation outlet pipe of the low-temperature constant temperature bath is connected to the upper cover low-temperature circulation cavity through the upper cover low-temperature circulation cavity inlet. The upper cover low-temperature circulation cavity outlet is connected to the main body low-temperature circulation cavity through the main body low-temperature circulation cavity inlet. The main body low-temperature circulation cavity outlet is sequentially connected to the in-vivo low-temperature circulation cavity through the in-vivo low-temperature circulation cavity total inlet and the in-vivo low-temperature circulation cavity inlet. After the in-vivo low-temperature circulation cavity outlet is connected to the in-vivo low-temperature circulation cavity total outlet, it is connected back to the low-temperature constant temperature bath through the low-temperature circulation inlet pipe.

[0017] The gas injection system includes a gas cylinder connected to a high-pressure plunger pump after passing through a pressure regulating gauge and a first stop valve. A second stop valve and a third stop valve are provided on the high-pressure pipeline of the high-pressure plunger pump. The tail end of the high-pressure pipeline is an injection gas pipe connected to a high-pressure capillary.

[0018] The temperature control system includes a low-temperature constant temperature bath, a low-temperature circulation inlet pipe, and a low-temperature circulation outlet pipe. The low-temperature circulation inlet pipe is connected to the total outlet of the low-temperature circulation cavity of the land, and the low-temperature circulation outlet pipe is connected to the upper cover low-temperature circulation cavity inlet.

[0019] The detection system includes a microscopic camera, a camera bracket, a detection auxiliary, and an optically movable platform. The detection auxiliary, the microscopic camera, and the camera bracket are all installed on the optically movable platform. The detection auxiliary uses a stainless steel iron sheet during Raman detection and uses a light source during optical detection.

[0020] The data acquisition system includes an image acquisition system and a temperature acquisition system. In the image acquisition system, the microscopic camera is connected to a data acquisition computer through a camera transmission line. In the temperature acquisition system, the temperature sensor is connected to the data acquisition computer through a data acquisition box.

[0021] On the upper cover of the reactor, the top visible window is fixed through the top visible window fixing ring, and on the main body of the reactor, the bottom visible window is fixed through the bottom visible window fixing ring.

[0022] The upper cover of the capillary reactor and the reactor main body are fixed by bolts, and a polytetrafluoroethylene seal ring is arranged in the seal ring placement notch on the reactor main body.

[0023] At the bottom of the reactor main body, there is a reactor fixing block for fixing on the optically movable platform during Raman detection. There are reactor fixing threaded rods on the reactor fixing block, and the number of reactor fixing threaded rods is four.

[0024] Advantages of the present invention: The device includes a capillary reactor, a gas injection system, a detection system, a temperature control system, and a data acquisition system. The capillary reactor is a sealed atmospheric-pressure container, and a high-pressure capillary can be placed inside. Visual sapphire windows are provided at both the top and bottom of the reactor; one end of the capillary reactor is connected to the gas injection system, which is jointly controlled by a gas cylinder, a pressure regulating gauge, and a high-pressure plunger pump; at the corresponding position of the visual window at the top of the capillary reactor, there is a Raman observation system for observing and recording the crystal structure of hydrates. Under non-Raman test conditions, it can be equivalently replaced by a microscopic imaging system for real-time monitoring of the morphological changes of hydrate crystal growth; the temperature control system is used to control the internal temperature of the capillary reactor, and the temperature data is measured by a temperature sensor; the data acquisition system records the temperature data, Raman spectra, or optical images in real time. This device can realize the full-cycle change of in-situ Raman or optical observation of hydrate crystal growth in the capillary.

[0025] The microscopic Raman device of the present invention has a unique design and can be used for both Raman spectroscopy detection and optical microscopic observation. However, it should be emphasized that these two functions are not carried out simultaneously, but are flexibly switched between different modes through a set of equipment, and have the following beneficial effects. First of all, through an integrated design, the present invention effectively integrates the two functions of Raman spectroscopy and optical microscopy in a set of devices. Researchers can quickly switch modes according to experimental needs, avoiding the complex operations of replacing equipment in traditional methods. Further, by providing independent optical observation mode and Raman detection mode, this device can adapt to different experimental needs. Finally, whether it is the accurate measurement of molecular vibration characteristics in Raman spectroscopy detection or the high-resolution imaging of crystal morphology by optical microscopy technology, this device can efficiently complete the tasks and is applicable to various experimental scenarios such as hydrate formation, crystal growth research, and others.

[0026] This device can realize the observation of optical microscopy and Raman spectroscopy in the same equipment. This device is applicable to both optical observation and Raman observation experimental backgrounds. While having optical observation conditions, it also takes into account the experimental characteristics of Raman spectroscopy, truly achieving the goal of "one set of device, two applications". This device not only significantly improves the experimental efficiency and reduces the experimental cost, but also provides more comprehensive data support for the research of hydrate crystals. The application of this device will provide strong tool support for in-depth research on the growth mechanism, phase change process, and structural characteristics of hydrate crystals, and at the same time lay a solid scientific foundation for the development and popularization of hydrate technology. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of a device for optical observation and structural analysis of hydrate crystal growth.

[0028] Figure 2 It is a three-dimensional view (front) of the capillary reactor.

[0029] Figure 3 It is a perspective view (back side) of the capillary reactor.

[0030] Figure 4 It is a front view of the capillary reactor.

[0031] Figure 5 It is a front view of the reactor main body.

[0032] Figure 6 It is a perspective view of the reactor main body.

[0033] Figure 7 It is a perspective view of the interior of the reactor main body.

[0034] In the figure: 1. Capillary reactor, 2. Detection auxiliary part, 3. Microscopic camera, 4. Gas cylinder, 5. Pressure regulating gauge, 6. First stop valve, 7. High-pressure plunger pump, 8. Low-temperature constant temperature bath, 9. Second stop valve, 10. Third stop valve, 11. Data acquisition box, 12. Data acquisition computer, 13. Low-temperature circulation outlet pipe, 14. Low-temperature circulation inlet pipe, 15. High-pressure pipeline, 16. Camera support, 17. Camera transmission line, 18. Optically movable platform, 19. Temperature sensor, 1a. Main body driver, 1b. Upper cover low-temperature circulation cavity, 1c. Top visible window, 1d. Temperature sensor connection port, 1e. Upper cover low-temperature circulation cavity outlet, 1f. Main body low-temperature circulation cavity outlet, 1g. Total inlet of the in-vivo low-temperature circulation cavity, 1h. Total outlet of the in-vivo low-temperature circulation cavity, 1i. Injection pipe fixing pressing piece, 1j. Injection pipe fixing card slot, 1k. Transmission rod, 1l. Inlet of the in-vivo low-temperature circulation cavity, 1m. Outlet of the in-vivo low-temperature circulation cavity, 1n. Capillary visible pressing piece, 1o. High-pressure capillary, 1p. In-vivo low-temperature circulation cavity, 1q. Reactor fixing screw rod, 1r. Capillary fixing table, 1s. Injection pipe fixing table, 1t. Temperature sensor card slot, 1u. Visible slot, 1v. Sealing ring placement slot, 1w. Top visible window fixing ring, 1x. Circulation cavity card slot, 1y. Spring, 1z. Bottom visible window, 11a. Reactor fixing block, 11b. Bottom visible serial port fixing ring, 11c. Upper cover low-temperature circulation cavity inlet, 11d. Main body low-temperature circulation cavity inlet, 11e. Fixing table card slot, 11f. Injection pipe, 11g. Main body low-temperature circulation cavity. Detailed implementation manners

[0035] The following further elaborates in detail the content of the present invention in conjunction with the accompanying drawings and specific implementation manners.

[0036] A microscopic Raman device for optical observation and structural analysis of hydrate crystal growth includes a capillary reactor 1, a gas injection system, a detection system, a temperature control system, and a data acquisition system.

[0037] The gas injection system includes a gas cylinder 4, a pressure regulator 5, a high-pressure pipeline 15, and a high-pressure plunger pump 7. A first stop valve 6 is installed at the outlet end of the pressure regulator 5. A second stop valve 9 and a third stop valve 10 are installed at the outlet end of the high-pressure plunger pump 7.

[0038] The detection system includes a microscopic camera 3, a camera bracket 16, a detection auxiliary 2, and an optically movable platform 18. The light source or stainless steel patch 2, the microscopic camera 3, and the camera bracket 16 are all installed on the optically movable platform 18. The selection of the detection auxiliary 2 is based on different test purposes.

[0039] The temperature control system includes a low-temperature constant temperature bath 8, a low-temperature circulation inlet pipe 14, and a low-temperature circulation outlet pipe 13. The low-temperature circulation inlet pipe 14 is connected to the main body low-temperature circulation chamber outlet 1f. The low-temperature circulation outlet pipe 13 is connected to the upper cover low-temperature circulation chamber inlet 11c.

[0040] The data acquisition system includes a Raman spectrum or optical image acquisition system and a temperature acquisition system. The Raman spectrum or optical image acquisition system includes a microscopic camera 3, a camera transmission line 17, and a data acquisition computer 12. The temperature acquisition system includes a temperature sensor 19, a data acquisition box 11, and a data acquisition computer 12.

[0041] On the outlet pipeline of the gas cylinder 4 in the gas injection system, a pressure regulator 5 and a first stop valve 6 are provided, and the outlet pipeline of the gas cylinder 4 is connected to the high-pressure plunger pump 7. A high-pressure pipeline 15 is provided at the outlet of the high-pressure plunger pump 7, and a second stop valve 9 and a third stop valve 10 are provided on the high-pressure pipeline 15. The end of the high-pressure pipeline 15 is an injection pipe 11f, and the injection pipe 11f is connected to the capillary reactor 1.

[0042] In the temperature control system, the low-temperature circulation inlet pipe 14 of the low-temperature constant temperature bath 8 is connected to the main body low-temperature circulation chamber outlet 1f of the capillary reactor 1; the low-temperature circulation outlet pipe 13 is connected to the upper cover low-temperature circulation chamber inlet 11c of the capillary reactor 1.

[0043] The capillary reactor 1 is arranged on the optically movable platform 18. The microscopic camera 3 is arranged above the capillary reactor 1 through the camera bracket 16, and the detection auxiliary 2 is arranged below the capillary reactor 1. When performing Raman detection, the detection auxiliary 2 uses a stainless steel patch, and when performing optical detection, the detection auxiliary 2 uses a light source.

[0044] The capillary reactor 1 includes a reactor main body and a reactor upper cover, and the reactor upper cover is provided with an upper cover low-temperature circulation chamber 1b.

[0045] On the outer side of the reactor main body is the main body low-temperature circulation cavity 11g. The inside of the reactor main body includes a transmission area and a capillary fixing area. In the transmission area, the main body driver 1a passes through the side wall of the reactor main body and is connected to the injection pipe fixing platform 1s. The injection pipe fixing platform 1s is sleeved on one end of the transmission rod 1k, and the other end of the transmission rod 1k is fixed on the capillary fixing platform 1r, and the capillary fixing platform 1r is fixed on the reactor main body. A spring 1y is sleeved outside the transmission rod 1k. After passing through the side wall of the reactor main body, the injection pipe 11f is fixed on the injection pipe fixing slot 1j of the injection pipe fixing platform 1s by the injection pipe fixing pressing piece 1i. When the main body driver 1a acts inward, it drives the injection pipe fixing platform 1s to move inward along the transmission rod 1k and compress the spring 1y, and the injection pipe fixing platform 1s drives the injection pipe 11f to move inward. Similarly, when the main body driver 1a acts outward, the spring 1y extends to make the injection pipe fixing platform 1s move outward along the transmission rod 1k, and the injection pipe fixing platform 1s drives the injection pipe 11f to move outward.

[0046] One end of the high-pressure capillary 1o is a sealed end and the other end is an open end. The open end of the high-pressure capillary 1o is connected to the injection pipe 11f.

[0047] In the capillary fixing area, the capillary fixing platform 1r and the in-vivo low-temperature circulation cavity 1p are fixed on the reactor main body. The high-pressure capillary 1o is arranged in the fixing platform slot 11e of the capillary fixing platform 1r and the circulation cavity slot 1x of the in-vivo low-temperature circulation cavity 1p. The capillary visible pressing piece 1n is fixed on the in-vivo low-temperature circulation cavity 1p and presses the high-pressure capillary 1o in the circulation cavity slot 1x. The capillary visible pressing piece 1n is provided with a visible notch 1u for observing the high-pressure capillary 1o.

[0048] When the main body driver 1a moves the injection pipe fixing platform 1s, the injection pipe 11f moves together with the injection pipe fixing platform 1s, so that the high-pressure capillary 1o moves along the fixing platform slot 11e and the circulation cavity slot 1x.

[0049] A low-temperature circulation structure is arranged in the capillary reactor. The upper cover low-temperature circulation cavity 1b, the main body low-temperature circulation cavity 11g and the in-vivo low-temperature circulation cavity 1p are connected.

[0050] The outlet of the low-temperature constant temperature bath 8 of the temperature control system is connected to the cover low-temperature circulation cavity 1b through the upper cover low-temperature circulation cavity inlet 11c. The upper cover low-temperature circulation cavity outlet 1e is connected to the main body low-temperature circulation cavity 11g through the main body low-temperature circulation cavity inlet 11d. The main body low-temperature circulation cavity outlet 1f is connected to the in-vivo low-temperature circulation cavity 1p through the in-vivo low-temperature circulation cavity total inlet 1g and the in-vivo low-temperature circulation cavity inlet 1l in sequence. After the in-vivo low-temperature circulation cavity outlet 1m is connected to the in-vivo low-temperature circulation cavity total outlet 1h, it is connected back to the inlet of the low-temperature constant temperature bath 8.

[0051] Visual windows for light transmission or observation are provided on both the upper cover of the reactor and the reactor body, and the high-pressure capillary 1o at the visual slot 1u is within the light transmission or observation area of the visual window; the detection system is used for Raman detection or optical detection microscopy imaging of the capillary reactor 1;

[0052] The top visual window 1c is fixed on the upper cover of the reactor through the top visual window fixing ring 1w, and the bottom visual window 1z is fixed on the reactor body through the bottom visual window fixing ring 11b.

[0053] The upper cover and the reactor body of the capillary reactor 1 are fixed by bolts, and a polytetrafluoroethylene sealing ring is arranged in the sealing ring placement slot 1v on the reactor body.

[0054] At the bottom of the reactor body, a reactor fixing block 11a for fixing on the optical movable platform 18 during Raman detection is provided. A reactor fixing threaded rod 1q is provided on the reactor fixing block 11a, and the number of the reactor fixing threaded rods 1q is four.

[0055] The Raman observation or microscopy imaging table includes a capillary visual pressing plate 1n and an in-vivo low-temperature circulation chamber 1p. The capillary visual pressing plate 1n has a visual slot 1u matching the diameter of the top visual window 1c and a temperature sensor card slot 1t corresponding to the temperature sensor connection port 1d. The in-vivo low-temperature circulation chamber 1p has a circulation chamber card slot 1x with the same diameter as the high-pressure capillary 1o.

[0056] Among them, the optical movable platform 18 is made of an aluminum alloy framework, and the capillary reactor 1 and the high-pressure pipeline 15 are both made of stainless steel materials. The injection pipe fixing card slot 1j, the injection pipe fixing pressing plate 1i, and the capillary visual pressing plate 1n ensure that the high-pressure capillary 1o is on the same horizontal line. There is a corresponding bottom visual window 1z at the bottom corresponding position of the top visual window 1c. During Raman detection, the detection auxiliary part 2 corresponding to the bottom of the capillary reactor 1 is a stainless steel iron sheet to prevent the Raman laser from penetrating and unable to identify the hydrate crystal structure. During optical detection, the detection auxiliary part 2 corresponding to the bottom of the capillary reactor 1 is a light source to facilitate photographing the morphological changes of the hydrate crystal.

[0057] The upper cover and the main body part of the capillary reactor 1 are fixedly connected by stainless steel screws. To ensure the sealing of the reactor, a polytetrafluoroethylene sealing ring is placed in the sealing ring placement slot 1v of the capillary reactor body. The top visual window fixing ring 1w, the upper cover low-temperature circulation chamber 1b, the injection pipe fixing pressing plate 1i, the injection pipe fixing table 1s, the capillary fixing table 1r, the capillary visual pressing plate 1n, and the in-vivo low-temperature circulation chamber 1p are all fixed by stainless steel screws. The reactor fixing block 11a on the back of the reactor body is used for fixing on the optical movable platform 18 during Raman detection,

[0058] The reactor fixing block 11a is provided with four reactor fixing threaded rods 1q. Using the above device for optical observation and structural analysis of hydrate crystal growth, which is applied to the observation of the crystal growth process of carbon dioxide gas hydrate at 2°C and 3.5 MPa, the usage method thereof is described. The carbon dioxide gas used in the experiment is from Dalian Special Gas Co., Ltd., and the purity is not less than 99.9%. The water used to form carbon dioxide hydrate is deionized water, which is prepared by the laboratory deionized water machine.

[0059] Its general working process is divided into two links according to the time sequence: device assembly and sealing test, crystal sample preparation and observation.

[0060] Example 1

[0061] Taking the optical observation of the crystal growth process of carbon dioxide hydrate as an example, the specific implementation scheme is as follows:

[0062] In the device assembly and sealing test link, first complete the connection of the high-pressure pipeline, and connect the gas cylinder 4, pressure regulating table 5, first stop valve 6, high-pressure plunger pump 7, second stop valve 9 and third stop valve 10 in sequence through the high-pressure pipeline 15. The open end of the high-pressure capillary 1o is connected to the high-pressure pipeline 15 to form a complete passage. During the connection process, pay attention to clamping the high-pressure gas injection pipeline in the gas injection pipe fixing card slot 1j and the gas injection pipe fixing pressing piece 1i.

[0063] At the same time, fix the capillary through the capillary fixing table 1r, capillary visual pressing piece 1n and circulation cavity card slot 1x in the transmission area. Then complete the construction of the capillary reactor 1, and install the temperature sensor 19 in the temperature sensor connection port 1d. Install the sealing ring in the sealing ring placement notch 1v, and use the bolt structure to tightly connect the reactor upper cover and the reactor main body. Install the wiped top visual window 1c on the capillary reactor upper cover, and fix the top visual window 1c through the bolt-fixed top visual window fixing ring 1w. Install the bottom visual window 1z in the same step by fixing it with the bottom visual window fixing ring 11b.

[0064] After the installation is completed, inject nitrogen gas with a pressure of 3.5 MPa into the high-pressure capillary 1o through the high-pressure plunger pump 7. The high-pressure plunger pump 7 is set to the constant pressure mode, and observe whether the gas volume indication in the pump decreases within 12 hours. If there is no decrease, it proves that the system has good sealing performance, and continue with the next process. If there is a decrease, use the leak detection system to check each connection point of the system until the volume indication remains unchanged.

[0065] In the crystal sample preparation and observation stage, first replace the nitrogen gas used for leak detection with high-purity carbon dioxide gas for the experiment. According to the volume of deionized water required for the experiment, use a micro syringe to inject the deionized water prepared in the laboratory into the high-pressure capillary 1o. Install it in the capillary reactor 1 according to the device assembly process. Then connect the microscope camera 3 to the data acquisition computer 12 through the camera transmission line 17. Connect the temperature sensor 19 to the data acquisition box 11 and to the data acquisition computer 12.

[0066] Adjustment of the position of the high-pressure capillary 1o: To ensure that the hydrate formation process is successfully observed and the final hydrate sample is in the center of the field of view as much as possible, the deionized water level needs to be adjusted to a suitable position before the experiment begins. When the main actuator 1a acts inward, it drives the gas injection pipe fixing platform 1s to move inward along the transmission rod 1k and compresses the spring 1y. The gas injection pipe fixing platform 1s drives the gas injection pipe 11f to move inward, thereby driving the high-pressure capillary 1o to move inward. Similarly, when the main actuator 1a acts outward, the spring 1y stretches to cause the gas injection pipe fixing platform 1s to move outward along the transmission rod 1k. The gas injection pipe fixing platform 1s drives the gas injection pipe 11f to move outward, thereby driving the high-pressure capillary 1o to move outward.

[0067] During the optical inspection, the light source is installed below the bottom visual window 1z. Then, the low-temperature circulation outlet pipe 13 is connected to the upper cover low-temperature circulation chamber inlet 11c, and the main body low-temperature circulation chamber outlet 1f is connected to the low-temperature circulation inlet pipe 14. The low-temperature thermostatic bath 8 is turned on, and the temperature of the capillary reactor 1 is maintained at 2°C for 30 minutes before the experiment is started. During this period, the temperature in the capillary reactor 1 is observed by the temperature sensor 19, and the set temperature of the low-temperature thermostatic bath 8 is adjusted to reach the required temperature for the experiment. After that, high-pressure carbon dioxide gas is injected to generate a carbon dioxide hydrate sample. Open the gas cylinder 4, adjust the pressure regulator 5 to the appropriate pressure, open the first stop valve 6, close the second stop valve 9, and inject the high-pressure carbon dioxide gas in the gas cylinder 4 into the high-pressure plunger pump 7. After a certain period of time, close the first stop valve 6, open the second stop valve 9, set the pressure value, and maintain 3.5 MPa in constant pressure mode. After the pressure and temperature are stable, turn on the light source and adjust it to a suitable brightness, adjust the microscope camera 3 to a suitable and clear shooting angle, turn on the data recording module of the data acquisition computer 12, and record the temperature data and image data at the same time. Open the third stop valve 10 and inject high-pressure carbon dioxide gas into the high-pressure capillary 1o. Observe the pressure reading of the high-pressure plunger pump 7, and after it stabilizes at 3.5 MPa, close the third stop valve 10, the second stop valve 9 and the high-pressure plunger pump 7. Finally, optically observe and record the growth process of carbon dioxide hydrate crystals.

[0068] Example 2

[0069] Taking the Raman determination of the crystal growth structure of carbon dioxide hydrate as an example, the specific implementation scheme is as follows:

[0070] In the device assembly and sealing test section, the implementation scheme is exactly the same as that for the optical observation of the carbon dioxide hydrate crystal growth process.

[0071] In the crystal sample preparation and observation section:

[0072] Adjustment of the position of the high-pressure capillary 1o: To ensure that the final hydrate sample is as much as possible at the center of the field of view, before the experiment starts, the deionized water liquid level needs to be adjusted to an appropriate position. When the main body driver 1a acts inward, it drives the injection pipe fixing platform 1s to move inward along the transmission rod 1k and compress the spring 1y. The injection pipe fixing platform 1s drives the injection pipe 11f to move inward, and then drives the high-pressure capillary 1o to move inward. Similarly, when the main body driver 1a acts outward, the spring 1y extends to make the injection pipe fixing platform 1s move outward along the transmission rod 1k. The injection pipe fixing platform 1s drives the injection pipe 11f to move outward, and then drives the high-pressure capillary 1o to move outward.

[0073] In Raman detection, install the stainless steel iron sheet at the position below the bottom visible window 1z, and use the reactor fixing screw rod 1q and the reactor fixing block 11a to fix the capillary reactor 1 on the existing observation table of the laboratory Raman equipment.

[0074] After that, connect the low-temperature circulation outlet pipe 13 and the upper cover low-temperature circulation cavity inlet 11c, and connect the main body low-temperature circulation cavity outlet 1f and the low-temperature circulation inlet pipe 14. Turn on the low-temperature constant temperature bath 8, maintain the temperature of the capillary reactor 1 at 2°C for 30 min and then start the experiment.

[0075] During this period, observe the temperature inside the capillary reactor 1 through the temperature sensor 19, and adjust the set temperature of the low-temperature constant temperature bath 8 to reach the temperature required for the experiment. Then start injecting high-pressure carbon dioxide gas to generate a carbon dioxide hydrate sample. Open the gas cylinder 4, adjust the pressure regulating table 5 to an appropriate pressure, open the first stop valve 6, close the second stop valve 9, and inject the high-pressure carbon dioxide gas in the gas cylinder 4 into the high-pressure plunger pump 7. After a certain period of time, close the first stop valve 6, open the second stop valve 9, set the pressure value, and maintain it at 3.5 MPa in the constant pressure mode.

[0076] After the pressure and temperature are stable, adjust the microscopic camera 3 to an appropriate and clear shooting angle, turn on the data recording module of the data acquisition computer 12, and record the temperature data and image data at the same time. Open the third stop valve 10, and inject the high-pressure carbon dioxide gas into the high-pressure capillary 1o. Observe the pressure indication of the high-pressure plunger pump 7. After it stabilizes at 3.5 MPa, close the third stop valve 10, the second stop valve 9, and the high-pressure plunger pump 7. Finally, conduct Raman observation and record the growth process of the carbon dioxide hydrate crystal.

[0077] In the crystal sample preparation and observation links, the Raman detection is the same as the optical detection of carbon dioxide hydrate crystal growth process. There are three main differences: First, stainless steel sheets are used in Raman detection of hydrate crystal growth structure, and light sources are required in optical detection. Stainless steel sheets prevent Raman lasers from penetrating hydrate crystals. Second, during Raman detection, the capillary reactor 1 needs to be fixed on the existing observation platform of the laboratory Raman equipment with the reactor fixing threaded rod 1q to ensure system stability; during optical detection, it is only necessary to place the capillary reactor 1 on the optical mobile platform, and align the light source with the visual window. Third, during Raman detection, the microscope camera 3 is the microscope camera that comes with the Raman equipment, which mainly completes the shooting and collection of the Raman spectrum of the hydrate crystal structure.

[0078] The above implementation cases are only for illustrating the technical concept and features of the present invention, and are intended to enable technicians in this field to understand the content of the present invention and implement it accordingly. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for optical observation and structural analysis of hydrate crystal growth, characterized in that: The device comprises a capillary reactor (1), a gas injection system, a detection system, a temperature control system and a data acquisition system; The capillary reactor (1) comprises a reactor body and a reactor cover, wherein the reactor cover is provided with an upper cover low-temperature circulation chamber (1b); The outside of the reactor body adopts a main low-temperature circulation chamber (11g), and the inside of the reactor body includes a transmission area and a capillary fixing area; in the transmission area, the main body transmission device (1a) passes through the side wall of the reactor body and is connected to the gas injection pipe fixing platform (1s); the gas injection pipe fixing platform (1s) is sleeved on one end of the transmission rod (1k), and the other end is fixed on the capillary fixing platform (1r); the outside of the transmission rod (1k) is sleeved with a spring (1y); the gas injection pipe (11f) is fixed in the gas injection pipe fixing slot (1j) of the gas injection pipe fixing platform (1s) through the gas injection pipe fixing pressing plate (1i); In the capillary fixing area, the capillary fixing platform (1r) and the in-vivo low-temperature circulation chamber (1p) are fixed on the reactor body, one end of the high-pressure capillary (1o) is a sealed end, and the other end is an open end, and the open end is connected to the gas injection pipe (11f); The open end is supported by a fixing table slot (11e) of a capillary fixing table (1r), and the sealed end is pressed into the circulation cavity slot (1x) by a capillary visual pressing sheet (1n) fixed to a low-temperature circulation cavity (1p) in the body, and the capillary visual pressing sheet (1n) is provided with a visual notch (1u) for observing the high-pressure capillary (1o); When the main body actuator (1a) moves the gas injection pipe fixing platform (1s), the gas injection pipe (11f) moves along with the gas injection pipe fixing platform (1s), so that the high-pressure capillary tube (1o) moves in the fixing platform slot (11e) and the circulation chamber slot (1x); The reactor upper cover and the reactor body are both provided with visual windows for light transmission or observation, and the high-pressure capillary (1o) at the visual notch (1u) is located within the light transmission or observation area of ​​the visual window; The gas injection system is connected to a high-pressure capillary (1o) of a capillary reactor (1); The detection system is used to perform Raman detection or optical detection on the capillary reactor (1); The temperature control system is in communication with the upper cover low-temperature circulation chamber (1b), the main body low-temperature circulation chamber (11g) and the in-body low-temperature circulation chamber (1p) of the capillary reactor (1).

2. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The low-temperature circulation outlet pipe (13) of the low-temperature thermostatic bath (8) in the temperature control system is connected to the upper cover low-temperature circulation chamber (1b) via the upper cover low-temperature circulation chamber inlet (11c), the upper cover low-temperature circulation chamber outlet (1e) is connected to the main body low-temperature circulation chamber (11g) via the main body low-temperature circulation chamber inlet (11d), and the main body low-temperature circulation chamber outlet (1f) is connected to the internal body low-temperature circulation chamber (1p) via the internal body low-temperature circulation chamber total inlet (1g) and the internal body low-temperature circulation chamber inlet (1l) in sequence; after the internal body low-temperature circulation chamber outlet (1m) is connected to the internal body low-temperature circulation chamber total outlet (1h), it is connected back to the low-temperature thermostatic bath (8) via the low-temperature circulation inlet pipe (14).

3. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The gas injection system comprises a gas cylinder (4) connected to a high-pressure plunger pump (7) via a pressure regulating gauge (5) and a first stop valve (6); a second stop valve (9) and a third stop valve (10) are arranged on a high-pressure pipeline (15) of the high-pressure plunger pump (7); and the tail end of the high-pressure pipeline (15) is a gas injection pipe (11f) connected to a high-pressure capillary tube (1o).

4. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The temperature control system comprises a low-temperature constant temperature tank (8), a low-temperature circulation inlet pipe (14) and a low-temperature circulation outlet pipe (13); the low-temperature circulation inlet pipe (14) is connected to the total outlet (1h) of the low-temperature circulation chamber of the ground, and the low-temperature circulation outlet pipe (13) is connected to the inlet (11c) of the low-temperature circulation chamber of the upper cover.

5. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The detection system comprises a microscope camera (3), a camera bracket (16), a detection auxiliary component (2) and an optical movable platform (18); the detection auxiliary component (2), the microscope camera (3) and the camera bracket (16) are all mounted on the optical movable platform (18); the detection auxiliary component (2) uses a stainless steel sheet when performing Raman detection, and the detection auxiliary component (2) uses a light source when performing optical detection.

6. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The data acquisition system comprises an image acquisition system and a temperature acquisition system. In the image acquisition system, a microscope camera (3) is connected to a data acquisition computer (12) via a camera transmission line (17); in the temperature acquisition system, a temperature sensor (19) is connected to the data acquisition computer (12) via a data acquisition box (11).

7. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The top visual window (1c) is fixed on the upper cover of the reaction kettle via a top visual window fixing ring (1w), and the bottom visual window (1z) is fixed on the main body of the reaction kettle via a bottom visual window fixing ring (11b).

8. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: The reactor cover of the capillary reactor (1) is fixed to the reactor body by bolts, and a polytetrafluoroethylene sealing ring is arranged in the sealing ring placement groove (1v) on the reactor body.

9. The device for optical observation and structural analysis of hydrate crystal growth according to claim 1, characterized in that: A reactor fixing block (11a) is arranged at the bottom of the reactor body and is fixed on the optical movable platform (18) during Raman detection. Reactor fixing threaded rods (1q) are arranged on the reactor fixing block (11a). The number of the reactor fixing threaded rods (1q) is four.

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