Device and method for measuring thickness of hydrate film based on continuous bubbling

Abstract

The invention relates to the technical field of hydrate basic physical property research, and provides a hydrate film thickness measuring device and method based on continuous bubbling, and the device comprises a buffer system, a reaction system, a constant temperature system, a gas supply system, a measuring system and an observation system. The technical problems of inaccurate hydrate film thickness measurement and inconvenient operation in the prior art can be solved, the measurement precision is high, and compared with a traditional measurement mode, the measurement cost is low, the operation is simple, the measurement time is short, and the measurement efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of basic physical property research of hydrates, and in particular to a device and method for measuring hydrate film thickness based on continuous bubbling. Background Art

[0002] Gas hydrates, also known as clathrate hydrates, are essentially a non-stoichiometric cage-like crystalline substance formed by the interaction of the main molecule - water and the guest molecule - gas under low temperature and high pressure conditions through the Van der Waals force. Natural gas hydrate resources are huge and are considered to be a more promising new, green, and clean energy substance after shale gas, coalbed methane, and tight gas. In addition, hydrates are also widely used in gas capture and separation, seawater desalination, CO2 submarine storage, and cold storage, and have good development prospects. Therefore, in-depth research on the growth mechanism of hydrates is of vital importance.

[0003] The growth process of hydrates can be divided into two parts: tangential growth and normal growth. When studying the normal growth of hydrates, it is necessary to consider the initial thickness, thickening rate and thickening direction of the hydrate film. The thickness of the hydrate film is usually measured directly using expensive and complex equipment such as optical microscopes, laser diffractometers and nuclear magnetic resonance imaging devices, or indirectly calculated using the hydrate tangential growth model. The thickness of the hydrate film is measured using a microscope, generally in a reactor with a visual window, but the interface effect will cause the hydrate film to be uneven, and the generated hydrate film is usually opaque. It is difficult to accurately measure the thickness of the hydrate film using conventional visual means, and there are technical problems such as inaccurate measurement and inconvenient operation.

[0004] The Chinese invention patent with patent number CN201810396902.X proposes a volume measurement device and method for natural gas hydrates, wherein the volume measurement device for natural gas hydrates includes a measuring cabin, a constant temperature device, a gas absorption bottle, an air intake device and a weighing device, and the connecting pipeline is provided with a first shut-off valve, and the gas absorption bottle contains a calcium chloride solution; when measuring, the first shut-off valve is first closed, and carbon dioxide gas is filled into the measuring cabin through the air intake device. When the carbon dioxide gas fills the measuring cabin, the first shut-off valve is opened again, and an inert gas is filled into the measuring cabin through the air intake device. The inert gas carries the carbon dioxide gas to the gas absorption bottle along the connecting pipeline, and the carbon dioxide gas reacts with the calcium chloride solution to generate solid calcium carbonate; the weighing device is used to weigh the mass of the solid calcium carbonate, which solves the problem that the prior art cannot accurately measure the volume of the natural gas hydrate sample while maintaining the original state of the natural gas hydrate sample.

[0005] Although this technical solution solves the technical problem of natural gas hydrate volume measurement, since the technical solution calculates the hydrate volume through the precipitation method and converts it into a weighing form, the hydrate thickness cannot be obtained. At the same time, this technical solution only provides a measurement method for the natural gas hydrate volume, which has certain limitations and is not suitable for the technical problem to be solved in this application. Therefore, it has certain disadvantages. Summary of the invention

[0006] The object of the present invention is to provide a hydrate film thickness measurement device and method based on continuous bubbling, which can solve the technical problems of inaccurate measurement of hydrate film thickness and inconvenient operation in the prior art.

[0007] In order to solve the above technical problems, the technical solution adopted in this application is:

[0008] An embodiment of the present application provides a hydrate film thickness measurement device based on continuous bubbling, including a buffer system for providing gas at a constant pressure, a reaction system, the reaction system is connected to the buffer system through pipeline A, and a pressure reducing valve is provided on the pipeline A, a constant temperature system cooperates with the buffer system and the reaction system to keep the buffer system and the reaction system at a predetermined temperature, an air supply system, the air supply system is connected to the buffer system through pipeline B, and an air inlet valve is provided on the pipeline B, a measuring system, the measuring system is connected to the reaction system through pipeline C, and a back pressure valve is provided on the pipeline C, and an observation system is used to observe the reaction system.

[0009] Before the experiment, the diameter d1, volume V and volume V of pure water injected into the high-pressure fully visible reactor were measured. W During the experiment, when a hydrate film was observed to form in the sapphire glass through the CCD camera, the reactor was continuously bubbled to allow hydrates to continue to form below the hydrate film. When the number of bubbles reached 100, the bubbling was stopped and the experiment was stopped. The diameter d2 of the bubbles and the total number of bubbles C during bubbling were measured; the temperature T and pressure P in the high-pressure fully visible reactor before the end of the reaction were recorded, and the amount of gas in the gas phase in the high-pressure fully visible reactor was calculated by the PR equation. g ; The total volume of gas in the high-pressure fully visible reactor was measured by the drainage method at room temperature (25°C) to obtain the volume V G ; First calculate the total amount of gas in the high-pressure fully visible reactor n total , the amount of gas in the formed hydrate n can be obtained hg ; Calculate the mass m1 of the gas in the formed hydrate, obtain the mass m2 of the water in the formed hydrate and the mass m3 of the formed hydrate; finally calculate the volume V of the formed hydrate HAnd the surface area S of the formed hydrate, and then the thickness δ of the formed hydrate is obtained.

[0010] In some embodiments of the present invention, the above-mentioned buffer system includes a buffer tank top cover and a buffer tank body, and the buffer tank top cover and the buffer tank body are connected by bolt A. The function of the buffer tank is to provide gas with constant pressure to the reaction system. If the gas in the gas supply system directly enters the reaction system, the gas pressure cannot be controlled and cannot be adjusted, and the technical effect of controlling the gas rate cannot be achieved. Therefore, a buffer system needs to be set up to achieve the technical purpose of filling gas control.

[0011] In some embodiments of the present invention, the buffer tank body is provided with an O-type rubber ring A, which is embedded in the top of the buffer tank body, and the outer wall of the O-type rubber ring A abuts against the bottom of the buffer tank cover. Since the buffer system is detachable and connected by bolts A, the air tightness of the connection between the buffer tank cover and the buffer tank body is reduced. Based on this, an O-type rubber ring A is provided, which is embedded in the top of the buffer tank body. After the bolts A are connected, the exposed surface of the O-type rubber ring A abuts against the inner wall of the buffer tank cover. At the same time, due to the action of the bolts A, it is interference fit with the buffer tank cover, thereby achieving a sealing effect, and achieving a pressure boosting seal when in use.

[0012] In some embodiments of the present invention, the reaction system adopts a high-pressure fully visual reactor, which includes an upper cover, a sapphire glass and a lower cover, one end of the sapphire glass is abutted against the upper cover, and the other end is abutted against the lower cover, and the upper cover and the lower cover are detachably connected; one end of pipeline A passes through the top cover of the buffer tank to be connected to the inside of the buffer system, and the other end passes through the lower cover to be connected to the inside of the reaction system. Since the device of the present application is provided with an observation system, it is necessary to limit and count the number of bubbles, so it is necessary to be able to observe the generation of bubbles inside the reaction system. Based on this, a high-pressure fully visual reactor is selected. Since the pressure in the reaction system is relatively high, the visualization material requires a certain strength support, so sapphire glass is selected to ensure the strength and stability of the reaction system. Pipeline A passes through the lower cover to allow the gas blown into the buffer system to form bubbles when it enters the reaction system through the lower cover because the reaction system is filled with liquid, thereby achieving the technical purpose of bubble counting and control.

[0013] In some embodiments of the present invention, the detachable connection between the upper cover and the lower cover is specifically a detachable connection via a bolt B. The bolt B is a long bolt. Since the diameters of the upper cover and the lower cover are longer than the diameter of the sapphire glass, the bolt B passes through the upper cover when in use, is located on the outer side of the sapphire glass, and is connected to the lower cover, thereby achieving the technical purpose of the detachable connection between the upper cover and the lower cover.

[0014] In some embodiments of the present invention, the upper cover is provided with an O-shaped rubber ring B, which is embedded in the bottom of the upper cover, and the outer wall of the O-shaped rubber ring B abuts against the top of the sapphire glass; the lower cover is provided with an O-shaped rubber ring C, which is embedded in the top of the lower cover, and the outer wall of the O-shaped rubber ring C abuts against the bottom of the sapphire glass. Since the upper cover and the lower cover are detachably connected, and the sapphire glass is abutted against the upper cover and the lower cover, there is a deficiency in airtightness. At the same time, there is no component used as a buffer at the abutment point, which may cause wear or even cracking of the sapphire glass. Therefore, an O-shaped rubber ring B and an O-shaped rubber ring C are provided, which are respectively embedded in the upper cover and the lower cover, and the exposed surfaces of the two are respectively abutted against the two ends of the sapphire glass. Due to the flexibility of the material, the sapphire glass can be effectively protected, play a buffering role, and prevent the occurrence of wear and cracking. At the same time, with the cooperation of the bolt B, an airtight effect is achieved, and the problem of air leakage can also be avoided after pressurization.

[0015] In some embodiments of the present invention, the above-mentioned constant temperature system adopts an air bath. Since the formation of hydrates is under low temperature and high pressure conditions, an air bath is required to maintain a constant low temperature environment.

[0016] In some embodiments of the present invention, the above-mentioned gas supply system adopts a high-pressure gas cylinder, one end of pipeline B is connected to the high-pressure gas cylinder, and the other end passes through the top cover of the buffer tank and is connected to the inside of the buffer system. The high-pressure gas cylinder can provide sufficient gas to enter the buffer system, thereby achieving the technical purpose of pressurizing the buffer system.

[0017] In some embodiments of the present invention, the above-mentioned measuring system includes a beaker and a high-precision long measuring cylinder. The high-precision long measuring cylinder is located in the beaker. One end of the pipeline C is located at the bottom of the high-precision long measuring cylinder and is connected to the interior of the high-precision long measuring cylinder. The other end passes through the upper cover and is connected to the interior of the reaction system. By setting up the measuring system, the volume of the discharged gas can be obtained by the drainage method. The operation is simple and the measurement accuracy is high, and the technical effect to be achieved in this application can be achieved.

[0018] In some embodiments of the present invention, the above also includes a monitoring system, which includes a computer, a data acquisition instrument, a temperature sensor A, a temperature sensor B, a pressure sensor A and a pressure sensor B; one end of the temperature sensor A and the pressure sensor A pass through the top cover of the buffer tank to communicate with the inside of the buffer system, and the other end is connected to the data acquisition instrument by communication; one end of the temperature sensor B and the pressure sensor B pass through the upper cover to communicate with the inside of the reaction system, and the other end is connected to the data acquisition instrument by communication; the computer and the data acquisition instrument are connected by communication, and a group of temperature and pressure sensors are provided in the buffer system and the reaction system. By transmitting information to the data acquisition instrument and feeding it back to the computer to obtain numerical values, it is convenient to count and control the required temperature and pressure.

[0019] In some embodiments of the present invention, the above also includes a control system, which includes an exhaust valve A, a control valve A, an exhaust valve B, a control valve B, an exhaust valve C, a pipeline D, a pipeline E and a pipeline F. One end of pipeline D passes through the top cover of the buffer tank and is connected to the inside of the buffer system, and the other end is connected to the exhaust valve A; the control valve A is arranged on pipeline A; one end of pipeline E is connected to pipeline A, and the other end passes through the upper cover and is connected to the inside of the reaction system, and the control valve B is arranged on pipeline E; one end of pipeline F passes through the upper cover and is connected to the inside of the reaction system, and the other end is connected to the exhaust valve B; the exhaust valve C is arranged on pipeline C, the exhaust valve A is used for regulating and vacuumizing the pressure in the buffer system, the control valve A is used for controlling the gas blown into the reaction system by the buffer system, the exhaust valve B is used for regulating and vacuumizing the pressure in the reaction system, the control valve B is used for pressurizing the reaction system by the buffer system, and the exhaust valve C is used for blowing the gas in the reaction system into the measurement system.

[0020] In some embodiments of the present invention, the above-mentioned observation system uses a CCD camera to observe the high-pressure fully visual reactor. The CCD camera and the data acquisition instrument are connected by communication, and the CCD camera is used to determine the formation of hydrates and the counting of bubbles; the CCD camera has a powerful automatic scanning function and clear image output. Compared with traditional cameras, it also has the advantages of small size, resistance to strong light, and easy operation.

[0021] On the other hand, an embodiment of the present application provides a method for using a hydrate film thickness measuring device based on continuous bubbling, comprising the following steps: C1. Inject 30 ml of pure water into the reaction system, C2. Set the temperature of the constant temperature system to 273.65 K, and evacuate the buffer system and the reaction system, C3. After the temperature stabilizes, methane is filled into the buffer system, and the internal temperature and pressure are recorded after stabilization, C4. Open the observation system for capture, adjust the inlet pressure to 10 MPa, and introduce a constant pressure gas into the reaction system, C5. After the observation system captures that the hydrate film is growing continuously and completely covers the liquid surface, adjust the outlet pressure of the back pressure valve, and uniformly bubble the experimental gas into the reaction system at a rate of one bubble per 10 seconds, C6. When the number of bubbles reaches 100, stop bubbling, close the pressure reducing valve, fill the high-precision long measuring cylinder with water and invert it in a beaker filled with water to keep the water level in the high-precision long measuring cylinder constant, open the exhaust valve C for exhaust, C7. After the hydrate is completely decomposed, read the reading of the high-precision long measuring cylinder and record it.

[0022] In some embodiments of the present invention, before performing the above-mentioned step C1, it is necessary to perform a leak detection operation on the device. The specific operation is: open the air inlet valve of the air supply system to inject nitrogen of a certain pressure into the buffer system, and then close the air inlet valve. The entire device is sealed for one day. If the value of the pressure sensor A is stable at a certain value, it indicates that the air tightness of the device is good. The nitrogen is released for subsequent experiments. Otherwise, it indicates that there is a leak in the device. Soap solution is usually used to check the leak. The existence of the leak seriously affects the accuracy of the device, so leak detection is necessary.

[0023] On the other hand, the present invention provides a method for measuring the thickness of a hydrate film based on a continuous bubbling device, comprising the following steps: S1, measuring the diameter d1 and volume V of the high-pressure fully visible reactor before the experiment; S2, measuring the volume V of pure water injected into the high-pressure fully visible reactor before the experiment. W S3, recording the temperature T and pressure P in the high-pressure fully visual reactor before the reaction ends, and calculating the amount of gas in the gas phase in the high-pressure fully visual reactor by the PR equation. g , the PR equation calculation formula is: g =PV / ZRT, S4, measure the diameter d2 of the bubble and the total number of bubbles C during bubbling, S5: measure the total volume V of the gas in the high-pressure fully visible reactor by the water displacement method at 25°C G S6: Calculate the total amount of gas in the high-pressure fully visible reactor n according to the data obtained in step S5 total , the calculation formula is: total =V G / 22.4, S7: Calculate the amount of gas in the formed hydrate n by using the data obtained in step S3 and step S5 hg , the calculation formula is: hg =n total -n g , S8: Calculate the mass m1 of the gas in the formed hydrate using the data obtained in step S7. The calculation formula is: m 1＝ M*n g , S9: Calculate the mass m2 of water in the formed hydrate using the data obtained in step S8. The calculation formula is: m2 = n g *N h *18, S10: Calculate the mass m3 of the formed hydrate using the data obtained in step S9, the calculation formula is: m3 = m1 + m2, S11: Calculate the volume V of the formed hydrate using the data obtained in step S10 H , the calculation formula is: V H =m3 / ρ h, S12: Calculate the surface area S of the formed hydrate using the data obtained in step S1 and step S4. The calculation formula is: S = π (d1 / 2) 2 +C*4π(d2 / 2) 2 , S13: Calculate the thickness δ of the formed hydrate using the data obtained in step S11 and step S12, and the calculation formula is: δ=V H / S.

[0024] In some embodiments of the present invention, the other required basic parameters include: hydrate number N h , the molar mass M of the gas and the hydrate density ρ h .

[0025] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0026] 1. It can measure the thickness of hydrate film with high measurement accuracy.

[0027] 2. Compared with traditional measurement methods, the measurement cost is low, the operation is simple, and the device structure is simple.

[0028] 3. Compared with traditional measurement methods, the measurement time is short and the measurement efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic structural diagram of a hydrate film thickness measuring device based on continuous bubbling provided by the present invention.

[0031] Icons: 1-high pressure gas cylinder; 2-intake valve; 3-O-type rubber ring A; 4-bolt A; 5-air bath; 8-buffer tank top cover; 9-buffer tank kettle; 10-pressure sensor A; 11-temperature sensor A; 12-exhaust valve A; 13-pressure reducing valve; 14-control valve A; 15-control valve B; 16-lower cover; 17-bolt B; 18-pressure sensor B; 19-temperature sensor B; 20-exhaust valve B; 21-O-type rubber ring B; 22-sapphire glass; 23-O-type rubber ring C; 24-upper cover; 25-exhaust valve C; 26-back pressure valve; 27-CCD camera; 28-beaker; 29-high precision long measuring cylinder; 30-computer; 31-data acquisition instrument; 32-pipeline A; 33-pipeline B; 34-pipeline C; 35-pipeline D; 36-pipeline E; 37-pipeline F. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to specific embodiments.

[0034] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0035] Example 1

[0036] Please refer to Figure 1 , Figure 1 Shown is a schematic structural diagram of an embodiment of the present invention.

[0037] The present embodiment provides a hydrate film thickness measurement device based on continuous bubbling, including a buffer system for providing gas at a constant pressure, a reaction system, the reaction system is connected to the buffer system through a pipeline A32, and a pressure reducing valve 13 is provided on the pipeline A32, a constant temperature system cooperates with the buffer system and the reaction system to keep the buffer system and the reaction system at a predetermined temperature, an air supply system, the air supply system is connected to the buffer system through a pipeline B33, and an air intake valve 2 is provided on the pipeline B33, a measuring system, the measuring system is connected to the reaction system through a pipeline C34, and a back pressure valve 26 is provided on the pipeline C34, and an observation system is used to observe the reaction system.

[0038] In order to adjust the gas pressure, the above-mentioned buffer system includes a buffer tank top cover 8 and a buffer tank body 9. The buffer tank top cover 8 and the buffer tank body 9 are connected by bolts A4. The function of the buffer tank is to provide gas with constant pressure to the reaction system. If the gas in the gas supply system directly enters the reaction system, the gas pressure cannot be controlled and cannot be adjusted, and the technical effect of controlling the gas rate cannot be achieved. Therefore, a buffer system needs to be set up to achieve the technical purpose of filling gas control.

[0039] In order to increase the sealing effect of the device, the buffer tank body 9 is provided with an O-type rubber ring A3, which is embedded in the top of the buffer tank body 9, and the outer wall of the O-type rubber ring A3 abuts against the bottom of the buffer tank top cover 8. Since the above-mentioned buffer system is a detachable method connected by bolts A4, the air tightness of the connection between the buffer tank top cover 8 and the buffer tank body 9 is reduced. Based on this, an O-type rubber ring A3 is provided, which is embedded in the top of the buffer tank body 9. After the bolt A4 is connected, the exposed surface of the O-type rubber ring A3 abuts against the inner wall of the buffer tank top cover 8. At the same time, due to the action of the bolt A4, it is interference fit with the buffer tank top cover 8, thereby achieving a sealing effect and achieving a pressure boosting seal when in use.

[0040] The above-mentioned reaction system adopts a high-pressure fully visible reactor, which includes an upper cover 24, a sapphire glass 22 and a lower cover 16. One end of the sapphire glass 22 is abutted against the upper cover 24, and the other end is abutted against the lower cover 16. The upper cover 24 and the lower cover 16 are detachably connected; one end of the pipeline A32 passes through the buffer tank top cover 8 to communicate with the inside of the buffer system, and the other end passes through the lower cover 16 to communicate with the inside of the reaction system. Since the device of the present application is provided with an observation system, it is necessary to limit and count the number of bubbles, so it is necessary to be able to observe the generation of bubbles inside the reaction system. Based on this, a high-pressure fully visible reactor is selected. Since the pressure in the reaction system is relatively high, the visualization material requires a certain strength support, so sapphire glass 22 is selected to ensure the strength and stability of the reaction system. The pipeline A32 passes through the lower cover 16 to allow the gas blown into the buffer system to form bubbles when it enters the reaction system through the lower cover 16, because the reaction system is filled with liquid, thereby achieving the technical purpose of bubble counting and control.

[0041] In order to realize the disassembly of the upper cover 24 and the lower cover 16, the detachable connection between the upper cover 24 and the lower cover 16 is specifically detachably connected by a bolt B17. The bolt B17 is a long bolt. Since the diameters of the upper cover 24 and the lower cover 16 are longer than the diameter of the sapphire glass 22, the bolt B17 passes through the upper cover 24 when in use, is located on the outer side of the sapphire glass 22, and is connected to the lower cover 16, thereby achieving the technical purpose of the detachable connection between the upper cover 24 and the lower cover 16.

[0042] In order to increase the sealing effect of the reaction system, the upper cover 24 is provided with an O-shaped rubber ring B21, which is embedded in the bottom of the upper cover 24, and the outer wall of the O-shaped rubber ring B21 abuts against the top of the sapphire glass 22; the lower cover 16 is provided with an O-shaped rubber ring C23, which is embedded in the top of the lower cover 16, and the outer wall of the O-shaped rubber ring C23 abuts against the bottom of the sapphire glass 22. Since the upper cover 24 and the lower cover 16 are detachably connected, and the sapphire glass 22 is abutted against the upper cover 24 and the lower cover 16, This is insufficient in terms of airtightness, and there is no component used as a buffer at the abutment, which may cause wear or even cracking of the sapphire glass 22. Therefore, an O-type rubber ring B21 and an O-type rubber ring C23 are provided, which are respectively embedded in the upper cover 24 and the lower cover 16, and the exposed surfaces of the two are respectively abutted against the two ends of the sapphire glass 22. Due to the flexibility of the material, the sapphire glass 22 can be effectively protected, and a buffering effect can be played to prevent the occurrence of wear and cracking. At the same time, with the cooperation of the bolt B17, an airtight effect is achieved, and the problem of air leakage can also be avoided after pressurization.

[0043] In order to achieve a low-temperature environment, the above-mentioned constant temperature system adopts an air bath 5. Since the formation of hydrates is under low-temperature and high-pressure conditions, the air bath 5 is required to maintain a constant low-temperature environment.

[0044] In order to pressurize the buffer system, the above-mentioned gas supply system adopts a high-pressure gas cylinder 1. One end of the pipeline B33 is connected to the high-pressure gas cylinder 1, and the other end passes through the buffer tank top cover 8 to be connected to the inside of the buffer system. The high-pressure gas cylinder 1 can provide sufficient gas to enter the buffer system, thereby achieving the technical purpose of pressurizing the buffer system.

[0045] The above-mentioned measuring system includes a beaker 28 and a high-precision long measuring cylinder 29. The high-precision long measuring cylinder 29 is located in the beaker 28. One end of the pipeline C34 is located at the bottom of the high-precision long measuring cylinder 29 and is connected to the interior of the high-precision long measuring cylinder 29. The other end passes through the upper cover 24 and is connected to the interior of the reaction system. By setting up the measuring system, the volume of the discharged gas can be obtained by the drainage method. The operation is simple and the measurement accuracy is high, which can achieve the technical effect to be achieved in this application.

[0046] In order to obtain the data required for calculation, the above also includes a monitoring system, which includes a computer 30, a data acquisition instrument 31, a temperature sensor A11, a temperature sensor B19, a pressure sensor A10 and a pressure sensor B18; one end of the temperature sensor A11 and the pressure sensor A10 pass through the buffer tank top cover 8 to communicate with the inside of the buffer system, and the other end is connected to the data acquisition instrument 31 by communication; one end of the temperature sensor B19 and the pressure sensor B18 pass through the upper cover 24 to communicate with the inside of the reaction system, and the other end is connected to the data acquisition instrument 31 by communication; the computer 30 and the data acquisition instrument 31 are connected by communication, and a group of temperature and pressure sensors are provided in the buffer system and the reaction system. By transmitting information to the data acquisition instrument 31 and feeding it back to the computer 30 to obtain a numerical value, it is convenient to count and control the required temperature and pressure.

[0047] In order to control the progress and suspension of the device, the above also includes a control system, which includes an exhaust valve A12, a control valve A14, an exhaust valve B20, a control valve B15, an exhaust valve C25, a pipeline D35, a pipeline E36 and a pipeline F37. One end of the pipeline D35 passes through the buffer tank top cover 8 and is connected to the inside of the buffer system, and the other end is connected to the exhaust valve A12; the control valve A14 is set on the pipeline A32; one end of the pipeline E36 is connected to the pipeline A32, and the other end passes through the upper cover 24 and is connected to the inside of the reaction system. The control valve B15 is set Placed on pipeline E36; one end of pipeline F37 passes through the upper cover 24 and is connected to the inside of the reaction system, and the other end is connected to the exhaust valve B20; the exhaust valve C25 is set on the pipeline C34, the exhaust valve A12 is used for regulating the pressure and vacuuming in the buffer system, the control valve A14 is used to control the gas blown into the reaction system by the buffer system, the exhaust valve B20 is used for regulating the pressure and vacuuming in the reaction system, the control valve B15 is used for pressurizing the reaction system by the buffer system, and the exhaust valve C25 is used to blow the gas in the reaction system into the measuring system.

[0048] In order to observe the number of bubbles, the above-mentioned observation system adopts a CCD camera 27 for observing the high-pressure fully visual reactor. The CCD camera 27 is connected to the data acquisition instrument 31 by communication. The CCD camera 27 is used to determine the formation of hydrates and the counting of bubbles. The CCD camera 27 has a powerful automatic scanning function and clear image output. Compared with traditional cameras, it also has the advantages of small size, resistance to strong light, and easy operation.

[0049] When using, if attached Figure 1 As shown, before the experiment, the diameter d1, volume V and volume V of pure water injected into the high-pressure fully visible reactor were measured. WDuring the experiment, when a hydrate film is observed to form in the sapphire glass 22 through the CCD camera 27, the reactor is continuously bubbled to allow hydrates to continue to form below the hydrate film. When the number of bubbles reaches 100, the bubbling is stopped and the experiment is stopped. The diameter d2 of the bubbles and the total number of bubbles C during bubbling are measured; the temperature T and pressure P in the high-pressure fully visible reactor before the end of the reaction are recorded, and the amount of gas in the gas phase in the high-pressure fully visible reactor is calculated by the PR equation. g ; The total volume of gas in the high-pressure fully visible reactor was measured by the drainage method at room temperature (25°C) to obtain the volume V G ; First calculate the total amount of gas in the high-pressure fully visible reactor n total , the amount of gas in the formed hydrate n can be obtained hg ; Calculate the mass m1 of the gas in the formed hydrate, obtain the mass m2 of the water in the formed hydrate and the mass m3 of the formed hydrate; finally calculate the volume V of the formed hydrate H And the surface area S of the formed hydrate, and then the thickness δ of the formed hydrate is obtained.

[0050] Example 2

[0051] This embodiment provides a method for measuring the thickness of a hydrate film based on continuous bubbling, comprising the following steps:

[0052] C1. Open the air inlet valve 2 of the high-pressure gas cylinder 1 to inject nitrogen of a certain pressure into the buffer tank kettle 9, and then close the air inlet valve 2. Seal the entire device for one day. If the value of the pressure sensor A10 is stable at a certain value, it means that the air tightness of the device is good. Release the nitrogen for subsequent experiments. Otherwise, it means that there is a leak in the device. Usually, soap solution is used to check the leak.

[0053] C2. Inject 30 ml of pure water into the high-pressure fully visible reactor;

[0054] C3. Set the temperature of the air bath 5 to 273.65K, and evacuate the buffer tank body 9 and the high-pressure fully visible reactor;

[0055] C4. After the temperature stabilizes, methane is charged into the buffer tank body 9. After stabilization, the internal temperature T1 = 273.65K and the pressure P1 = 8MPa are recorded;

[0056] C5. Turn on the CCD camera 27 to capture, adjust the air intake pressure to 10 MPa, and introduce methane at a constant pressure into the high-pressure fully visible reactor;

[0057] C6. After the CCD camera 27 captures the continuous growth of the hydrate film and completely covers the liquid surface, the pressure at the outlet of the back pressure valve 26 is adjusted to uniformly blow the experimental gas into the high-pressure fully visible reactor at a rate of one bubble per 10 seconds;

[0058] C7. When the number of bubbles reaches 100, stop bubbling and close the pressure reducing valve 13. At this time, record the diameter d of the bubbles during bubbling. 21 =5mm, total number of bubbles C1 = 100, fill the high-precision long measuring cylinder 29 with water and invert it in the beaker 28 filled with water, keep the water level in the high-precision long measuring cylinder 29 constant, and open the exhaust valve C25 to exhaust;

[0059] C8. After the hydrate is completely decomposed, read the high-precision long measuring cylinder 29 reading V g1 =1200ml, the diameter d of the high pressure fully visible reactor was determined before the experiment 11 =100mm, volume V1 = 5000ml, volume V of pure water injected into the high pressure fully visible reactor W1 =30ml.

[0060] Calculation process:

[0061] According to the PR equation n g1 =P1V1 / (ZRT1)(taking Z=0.8, R=8.314J / (mol·K)), we can get n g1 =8×5000 / (0.8×8.314×273.65)≈21.7mol;

[0062] n total1 =V g1 / 22.4=1200 / 22.4≈53.6mol;

[0063] n hg1 =n total1 -n g1 =53.6-21.7=31.9mol;

[0064] It is known that the molar mass of methane is M = 16 g / mol and the number of hydrates is N. h =5.75, hydrate density ρ h =0.9g / cm 3 , then m 11 =M*n hg1 =16×31.9=510.4g;

[0065] m 21 =n hg1 *N h *18=31.9×5.75×18≈3237.2g;

[0066] m31 =m 11 +m 21 =510.4+3237.2=3747.6g;

[0067] V H1 =m 31 / ρ h =3747.6 / 0.9≈4164cm 3 ;

[0068] S1=π(d 11 / 2)2+C1*4π(d 21 / 2)2=3.14×(100 / 2)2+100×4×3.14×(5 / 2)2=7850+7850

[0069] =15700mm 2 =157cm 2 ;

[0070] δ1=V H1 / S1=4164 / 157≈26.5mm, the thickness of the hydrate membrane is 26.5mm.

[0071] Example 3

[0072] This embodiment 3 is basically the same as embodiment 2, except that the temperature of the air bath 5 is set to 274 K. After the buffer tank body 9 is filled with methane gas and stabilized, the internal temperature T2 = 274 K and the pressure P2 = 8.5 MPa are recorded.

[0073] Adjust the air inlet pressure to 10.5MPa. After the bubbling is completed, record the bubble diameter d 22 =4.8mm, total number of bubbles C2 = 100, after the hydrate is completely decomposed, read the high-precision long measuring cylinder 29 reading V g2 =1180ml, the diameter d in the high pressure fully visible reactor was measured before the experiment 12 =100mm, volume V2 = 5000ml, volume V of pure water injected into the high pressure fully visible reactor W2 =30ml.

[0074] Calculation process:

[0075] n g2 =P2V2 / (ZRT2)(taking Z=0.8, R=8.314J / (mol·K)), we can get

[0076] n g2 =8.5×5000 / (0.8×8.314×274)≈23.4mol;

[0077] ntotal2 =V g2 / 22.4=1180 / 22.4≈52.7mol;

[0078] n hg2 =n total2 -n g2 =52.7-23.4=29.3mol;

[0079] m 12 =M*n hg2 =16×29.3=468.8g;

[0080] m 22 =n hg2 *N h *18=29.3×5.75×18≈3054.5g;

[0081] m 32 =m 12 +m 22 =468.8+3054.5=3523.3g;

[0082] V H2 =m 32 / ρ h =3523.3 / 0.9≈3914.8cm 3 ;

[0083] S2=π(d 12 / 2)2+C2*4π(d 22 / 2)2=3.14×(100 / 2)2+100×4×3.14×(4.8 / 2)2=7850+72

[0084] 34.6 = 15084.6 mm 2 =150.85cm 2 ;

[0085] δ2=V H2 / S2=3914.8 / 150.85≈26.0mm, the thickness of the hydrate membrane is 26.0mm.

[0086] Example 4

[0087] This embodiment 4 is basically the same as embodiment 2, except that the temperature of the air bath 5 is set to 273.5 K. After the buffer tank body 9 is filled with methane gas and stabilized, the internal temperature T3 = 273.5 K and the pressure P3 = 7.5 MPa are recorded.

[0088] Adjust the air inlet pressure to 9.5MPa. After the bubbling is completed, record the bubble diameter d during the bubbling. 23=5.2mm, total number of bubbles C3 = 100, after the hydrate is completely decomposed, read the high-precision long measuring cylinder 29 reading V g3 =1220ml, the diameter d in the high pressure fully visible reactor was measured before the experiment 13 =100mm, volume V3 = 5000ml, volume V of pure water injected into the high pressure fully visible reactor W3 =30ml.

[0089] Calculation process:

[0090] n g3 =P3V3 / (ZRT3)(taking Z=0.8, R=8.314J / (mol·K)), we can get

[0091] n g3 =7.5×5000 / (0.8×8.314×273.5)≈20.5mol;

[0092] n total3 =V g3 / 22.4=1220 / 22.4≈54.5mol;

[0093] n hg3 =n total3 -n g3 =54.5-20.5=34.0mol;

[0094] m 13 =M*n hg3 =16×34.0=544.0g;

[0095] m 23 =n hg3 *N h *18=34.0×5.75×18≈3513.0g;

[0096] m 33 =m 13 +m 23 =544.0+3513.0=4057.0g;

[0097] V H3 =m 33 / ρ h =4057.0 / 0.9≈4507.8cm 3 ;

[0098] S3=π(d 13 / 2)2+C3*4π(d 23 / 2)2=3.14×(100 / 2)2+100×4×3.14×(5.2 / 2)2=7850+84

[0099] 90.6 = 16340.6 mm 2 =163.41cm 2 ;

[0100] δ3=V H3 / S3=4507.8 / 163.41≈27.6mm, the thickness of the hydrate membrane is 27.6mm.

[0101] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydrate film thickness measuring device based on continuous bubbling, characterized in that: include: A buffer system to provide gas at a constant pressure; A reaction system, wherein the reaction system is connected to the buffer system via a pipeline A, and a pressure reducing valve is provided on the pipeline A; A constant temperature system, cooperating with the buffer system and the reaction system to keep the buffer system and the reaction system at a predetermined temperature; An air supply system, the air supply system is connected to the buffer system through a pipeline B, and an air intake valve is provided on the pipeline B; A measuring system, wherein the measuring system is connected to the reaction system via a pipeline C, and a back pressure valve is provided on the pipeline C; Observation system, used to observe the reaction system.

2. A hydrate film thickness measuring device based on continuous bubbling according to claim 1, characterized in that: The buffer system comprises a buffer tank top cover and a buffer tank kettle body, and the buffer tank top cover and the buffer tank kettle body are connected by bolts A.

3. A hydrate film thickness measuring device based on continuous bubbling according to claim 2, characterized in that: The buffer tank body is provided with an O-type rubber ring A, which is embedded in the top of the buffer tank body, and the outer wall of the O-type rubber ring A abuts against the bottom of the buffer tank top cover.

4. A hydrate film thickness measuring device based on continuous bubbling according to claim 2, characterized in that: The reaction system adopts a high-pressure fully visible reactor, which includes an upper cover, a sapphire glass and a lower cover. One end of the sapphire glass is abutted against the upper cover, and the other end is abutted against the lower cover. The upper cover and the lower cover are detachably connected; one end of the pipeline A passes through the top cover of the buffer tank and is connected to the interior of the buffer system, and the other end passes through the lower cover and is connected to the interior of the reaction system.

5. A hydrate film thickness measuring device based on continuous bubbling according to claim 4, characterized in that: The upper cover is provided with an O-shaped rubber ring B, which is embedded in the bottom of the upper cover, and the outer wall of the O-shaped rubber ring B abuts against the top of the sapphire glass; the lower cover is provided with an O-shaped rubber ring C, which is embedded in the top of the lower cover, and the outer wall of the O-shaped rubber ring C abuts against the bottom of the sapphire glass.

6. A hydrate film thickness measuring device based on continuous bubbling according to claim 2, characterized in that: The gas supply system adopts a high-pressure gas cylinder, one end of the pipeline B is connected to the high-pressure gas cylinder, and the other end passes through the buffer tank top cover and is connected to the inside of the buffer system.

7. A hydrate film thickness measuring device based on continuous bubbling according to claim 4, characterized in that: The measuring system includes a beaker and a high-precision long measuring cylinder, wherein the high-precision long measuring cylinder is located in the beaker, one end of the pipeline C is located at the bottom of the high-precision long measuring cylinder and is connected to the interior of the high-precision long measuring cylinder, and the other end passes through the upper cover and is connected to the interior of the reaction system.

8. The hydrate film thickness measuring device based on continuous bubbling according to claim 4, characterized in that: It also includes a monitoring system, which includes a computer, a data acquisition instrument, a temperature sensor A, a temperature sensor B, a pressure sensor A and a pressure sensor B; one end of the temperature sensor A and the pressure sensor A pass through the top cover of the buffer tank to communicate with the inside of the buffer system, and the other end is connected to the data acquisition instrument by communication; one end of the temperature sensor B and the pressure sensor B pass through the top cover to communicate with the inside of the reaction system, and the other end is connected to the data acquisition instrument by communication; the computer is connected to the data acquisition instrument by communication.

9. The hydrate film thickness measuring device based on continuous bubbling according to claim 4, characterized in that: It also includes a control system, which includes an exhaust valve A, a control valve A, an exhaust valve B, a control valve B, an exhaust valve C, a pipeline D, a pipeline E and a pipeline F, one end of the pipeline D passes through the top cover of the buffer tank and is connected to the inside of the buffer system, and the other end is connected to the exhaust valve A; the control valve A is arranged on the pipeline A; one end of the pipeline E is connected to the pipeline A, and the other end passes through the upper cover and is connected to the inside of the reaction system, and the control valve B is arranged on the pipeline E; one end of the pipeline F passes through the upper cover and is connected to the inside of the reaction system, and the other end is connected to the exhaust valve B; the exhaust valve C is arranged on the pipeline C.

10. A method for using the hydrate film thickness measuring device according to any one of claims 1 to 9, characterized in that: The following steps are involved: C1, inject 30 ml of pure water into the reaction system; C2, setting the temperature of the constant temperature system to 273.65K, and evacuating the buffer system and the reaction system; C3. After the temperature stabilizes, methane is charged into the buffer system, and after stabilization, the internal temperature and pressure are recorded; C4, opening the observation system for capture, adjusting the inlet pressure to 10 MPa, and introducing a gas at a constant pressure into the reaction system; C5. After the observation system captures the continuous growth of the hydrate film and completely covers the liquid surface, the pressure at the outlet of the back pressure valve is adjusted to uniformly bubble the experimental gas into the reaction system at a rate of one bubble per 10 seconds; C6. When the number of bubbles reaches 100, stop bubbling, close the pressure reducing valve, fill the high-precision long graduated cylinder with water and invert it in the beaker filled with water to keep the water level in the high-precision long graduated cylinder constant, and open the exhaust valve C to exhaust; C7. After the hydrate is completely decomposed, read the reading of the high-precision long measuring cylinder and record it.

Images