A device for sampling and vaporizing a liquid-phase medium

Abstract

The present invention discloses a device for sampling and gasifying a liquid-phase medium, comprising: a sampling unit including a sampling probe for collecting the liquid-phase medium; a first gasification unit for gasifying the liquid-phase medium collected by the sampling unit; and a throttling unit disposed on a first pipeline for connecting the sampling unit and the first gasification unit, configured to regulate the flow rate of the liquid-phase medium entering the first gasification unit, and based on pressure-reducing gasification, enabling the liquid-phase medium entering the first gasification unit to have sufficient subcooling degree. By providing the throttling unit, on the one hand, it is used to regulate the flow rate of the liquid-phase medium entering the first gasification unit to adapt to the change of the heat load of the first gasification unit; on the other hand, a small part of the liquid-phase medium is gasified under reduced pressure before entering the first gasification unit, and the gasified part of the liquid-phase medium absorbs heat, increasing the subcooling degree of the remaining liquid-phase medium, effectively avoiding fractionation of the liquid-phase medium before gasification in the first gasification unit.

Description

[0001] This invention claims the priority of the patent application with the filing date of July 8, 2020 and the application number of CN202010652011.3, the content of which is incorporated herein by reference. Technical Field

[0002] This invention generally relates to the technical field of liquid sampling and gasification, and particularly relates to a device for sampling and gasifying cryogenic liquid-phase media. Background Art

[0003] When sampling and analyzing media that are in a liquid phase at low temperatures, such as LNG, LPG, and other cryogenic liquid-phase media, they need to be converted into a gas phase for easy analysis. Since cryogenic liquid-phase media often contain multiple components with different boiling points, when they are heated or depressurized and gasified, the components with different boiling points will be converted into a gas phase at different times or in the order of increasing boiling point, resulting in a fractionation phenomenon and causing deviations in the analysis and measurement results.

[0004] To ensure the accuracy of the analysis results, cryogenic liquid-phase media must be kept in a supercooled state before gasification, without any component fractionation and gasification, and after gasification, it should be ensured that the gas component mixing ratio is exactly the same as the liquid component ratio. In order to avoid the measurement deviation caused by the fractional gasification during the distillation range in the prior art, homogenization containers with a volume of more than 20L are often used, resulting in very poor real-time performance of the analyzed components.

[0005] Among them, the vaporizer is one of the key components for converting liquid-phase media into a gas phase. The vaporizers in the prior art use changes in the cross-sectional area to control the pressure of the fluid to make the fluid reach the supercritical state. It does not consider the thermal inertia of the heating element, and it is difficult to achieve the working state of sealing and heating the liquid-phase sample to the critical state and then releasing it, and it is difficult to be applied to actual operations. Summary of the Invention

[0006] In view of the above-mentioned defects or deficiencies in the prior art, this invention expects to provide a device for sampling and gasifying liquid-phase media, in order to achieve the stable conversion of liquid-phase media containing components with different boiling points into gas samples, thereby improving the accuracy of the component analysis of liquid-phase media.

[0007] As the first aspect of this invention, this invention provides a device for sampling and gasifying liquid-phase media.

[0008] Preferably, the device for sampling and gasifying liquid-phase media includes:

[0009] A sampling unit, including a sampling probe, for collecting the liquid-phase media;

[0010] A first gasification unit, for gasifying the liquid-phase media collected by the sampling unit; and

[0011] A throttling unit is provided on a first pipeline for connecting the sampling unit and the first gasification unit, and is configured to adjust the flow rate of the liquid-phase medium entering the first gasification unit and ensure that the liquid-phase medium entering the first gasification unit has sufficient subcooling based on pressure-reducing gasification.

[0012] Preferably, the throttling unit includes a throttling element and a liquid separation pipeline, and the throttling element is provided on the liquid separation pipeline;

[0013] The throttling element includes a housing. Liquid inlets and outlets are provided at opposite ends of the housing. A throttling channel is provided inside the housing, and the liquid inlets, outlets, and throttling channel are interconnected; the cross-sectional area of the throttling channel gradually decreases first and then gradually increases in the direction from the liquid inlet to the liquid outlet;

[0014] Among them, a part of the liquid-phase medium collected by the sampling unit enters the first gasification unit via the first pipeline, and another part of the liquid-phase medium collected by the sampling unit enters the throttling element via the liquid separation pipeline communicated with the first pipeline, and a gas-liquid mixture is generated by pressure-reducing gasification and discharged from the liquid outlet.

[0015] Preferably, the first gasification unit includes a first heat exchange element;

[0016] The first heat exchange element includes a columnar heat-conducting body. A liquid flow channel extending along the length direction of the columnar heat-conducting body is provided inside the columnar heat-conducting body. One end of the liquid channel has an opening to form a liquid inlet, and the other end of the liquid channel is closed; wherein, a number of through holes communicating with the liquid flow channel are provided on the columnar heat-conducting body surrounding the liquid flow channel, and a guiding pipe is connected to the outlet of each through hole; the liquid-phase medium from the sampling unit enters the liquid flow channel via the liquid inlet, and the gas generated by heat gasification is discharged via the through holes and the guiding pipes and converges at the outlet end of the guiding pipe.

[0017] Preferably, a nozzle is provided between the outlet end of the first pipeline and the liquid inlet, and the liquid-phase medium enters the liquid flow channel via the nozzle. The outlet of the nozzle is of a constricted structure; wherein, the inlet end of the liquid separation pipeline is connected to the pipe wall of the first pipeline near the outlet end of the first pipeline.

[0018] Preferably, it further includes a closed vacuum insulation housing. The sampling unit and the throttling unit are integrated in the vacuum insulation housing, and the inlet end of the sampling probe is exposed outside the vacuum insulation housing.

[0019] Preferably, a first valve for controlling the on-off of the sampling unit is provided on the first pipeline, and the free end of the valve stem of the first valve is exposed outside the vacuum insulation housing; preferably, the first valve is a cryogenic-resistant stop valve.

[0020] Preferably, it further includes an emission unit connected to the throttling unit for gasifying the gas-liquid mixed phase generated by the throttling unit under reduced pressure and then transporting it to the main gas recovery pipeline;

[0021] Wherein, the emission unit includes an outlet end connecting the liquid separation pipeline and a second pipeline of the main gas recovery pipeline, and a second gasification unit for gasifying the gas-liquid mixed phase is provided on the second pipeline; wherein, the outlet end of the liquid separation pipeline is close to the sampling unit.

[0022] Preferably, the emission unit further includes a pressure transmitter and a second valve provided between the second gasification unit and the main gas recovery pipeline; the second valve is a back pressure valve.

[0023] Preferably, an electric heat tracing band is provided on the second pipeline.

[0024] Preferably, temperature measuring elements are provided on the first heat exchange element, the first pipeline close to the nozzle, and the second pipeline between the throttling unit and the second gasification unit.

[0025] Advantages of the present invention:

[0026] 1) By setting the throttling unit, on the one hand, the liquid phase medium flowing through the throttling unit is throttled, so as to adjust the flow rate of the liquid phase medium entering the first gasification unit to adapt to the change of the heat load of the first gasification unit; on the other hand, a small part of the liquid phase medium is gasified under reduced pressure before entering the first gasification unit, and the gasified part of the liquid phase medium absorbs heat, increasing the subcooling degree of the remaining liquid phase medium, effectively avoiding fractionation of the liquid phase medium before gasification in the first gasification unit;

[0027] 2) The first gasification unit of the present invention adopts a honeycomb first heat exchange element, which has a high energy density and a large heat exchange area, and the gasification is sufficient and rapid. It can instantaneously gasify each component with different boiling points in the liquid phase medium with a wide fractionation range at the same time, and can minimize the time in the fractionation state, making the gas components and liquid components consistent. This not only helps to improve the accuracy of the liquid phase medium component analysis, but also eliminates the large-volume homogenization container and improves the real-time analysis;

[0028] 3) The sampling unit and the throttling unit of the present invention are both placed in a closed vacuum heat-insulated housing formed by heat-insulating materials, which can not only effectively keep the cold of the liquid medium, but also insulate the sampling unit, the throttling unit from the first gasification unit, prevent cold and heat convection, thereby effectively suppressing the premature gasification of the low-boiling components in the liquid phase medium, ensuring the acquisition of representative samples and improving the accuracy of the liquid phase medium component analysis. Description of the Drawings

[0029] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments read in conjunction with the accompanying drawings:

[0030] Figure 1 Schematic structural diagram of a device for liquid-phase medium sampling and gasification, which is a preferred embodiment of the present invention;

[0031] Figure 2 is Figure 1 Enlarged view of the structure of part A of the device shown.

[0032] Reference numerals: sampling unit 1, sampling probe 10, inlet end 101, first gasification unit 2, first heat exchange element 20, columnar heat-conducting body 201, liquid inlet 202, through hole 203, guiding pipe 204, outlet end 205, hollow outer shell 21, gas outlet 210, throttling unit 3, throttling element 30, liquid separation pipeline 31, inlet end 311, outlet end 312, first pipeline 4, outlet end 41, nozzle 42, vacuum heat-insulating outer shell 5, first valve 6, valve stem 60, discharge unit 7, second pipeline 70, second gasification unit 71, pressure transmitter 72, second valve 73, electric tracing band 74, gas recovery main pipe 8, temperature measuring element 9, sampling pipeline 100, short neck 200, flange 300, heat-insulating structure 400. Detailed implementation manners

[0033] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the relevant invention and not for limiting the invention. In addition, it should be noted that for the sake of description, only parts related to the invention are shown in the drawings.

[0034] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and embodiments.

[0035] It should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0036] It should be noted that in the description of the present invention, terms such as "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0037] It should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Please refer to Figure 1 , which shows a device for liquid-phase medium sampling and vaporization according to a preferred embodiment of the present invention, including a sampling unit 1, a first vaporization unit 2, and a throttling unit 3. Among them, the sampling unit 1 includes a sampling probe 10 for collecting the liquid-phase medium; the first vaporization unit 2 is used to vaporize the liquid-phase medium collected by the sampling unit 1; the throttling unit 3 is disposed on a first pipeline 4 for connecting the sampling unit 1 and the first vaporization unit 2, and is configured to adjust the flow rate of the liquid-phase medium entering the first vaporization unit 2, and based on pressure-reducing vaporization, make the liquid-phase medium entering the first vaporization unit 2 have sufficient subcooling degree.

[0039] In this embodiment, the sampling probe 10 of the sampling unit 1 is generally fixed in the main pipeline for loading / unloading the liquid-phase medium, and the liquid-phase medium at the sampling point is in a subcooled state with stable flow rate and pressure.

[0040] In this embodiment, the throttling unit 3 adjusts the flow rate of the liquid-phase medium entering the first vaporization unit 2 through throttling, so that a part of the liquid-phase medium enters the throttling unit 3 and does not enter the first vaporization unit 2, and causes this part to undergo pressure-reducing vaporization, enabling this part of the liquid-phase medium to absorb the heat of the remaining majority of the liquid-phase medium during the pressure-reducing vaporization process, thereby providing subcooling protection for the majority of the liquid-phase medium entering the first vaporization unit 2, increasing the subcooling degree of the majority of the liquid-phase medium entering the first vaporization unit 2, keeping it in a liquid state all the time, and preventing the early vaporization of low-boiling components therein.

[0041] In this embodiment, the first vaporization unit 2 provides a heat medium environment to achieve the complete and rapid vaporization of the liquid-phase medium.

[0042] Among them, the liquid-phase medium includes, but is not limited to, any one or a mixture of more than one of liquefied natural gas (LNG), liquefied petroleum gas, liquefied coal gas, liquid nitrogen, and liquid argon.

[0043] Furthermore, in some preferred embodiments of the present invention, the throttling unit 3 includes a throttling element 30 and a liquid separation pipeline 31, and the throttling element 30 is disposed on the liquid separation pipeline 31;

[0044] Among them, the throttling element 30 includes a housing, and liquid inlet and outlet ports are provided at opposite ends of the housing. A throttling channel is provided inside the housing, and the liquid inlet port, the liquid outlet port, and the throttling channel are in communication with each other; the cross-sectional area of the throttling channel gradually decreases first and then gradually increases in the direction from the liquid inlet port to the liquid outlet port;

[0045] Among them, a part of the liquid-phase medium collected by the sampling unit 1 enters the first gasification unit 2 through the first pipeline 4, and another part of the liquid-phase medium collected by the sampling unit 1 enters the throttling element 30 through the liquid separation pipeline 31 communicated with the first pipeline 1. After being depressurized and gasified, a gas-liquid mixed phase is discharged from the liquid outlet port of the throttling element 30.

[0046] Specifically, the throttling channel is sequentially provided with a liquid inlet area, a throttling area, and a liquid outlet area in the fluid flow direction. The liquid inlet port is used to guide the fluid into the liquid inlet area, and the liquid outlet port is used to guide the fluid flowing out of the throttling area into the liquid outlet area; among them, the cross-sectional area of the liquid inlet area gradually decreases in the direction from the liquid inlet port to the throttling area, and the cross-sectional area of the liquid outlet area gradually increases in the direction from the throttling area to the liquid outlet port, so that the cross-sectional area of the throttling channel gradually decreases first and then gradually increases in the direction from the liquid inlet port to the liquid outlet port;

[0047] Among them, the liquid separation pipeline 31 includes an inlet end 311 and an outlet end 312. Its inlet end 311 is communicated with the first pipeline 4. The liquid-phase medium enters the throttling element 30 from the liquid inlet port of the throttling element 30 through the inlet end 311 of the liquid separation pipeline 31. The liquid-phase medium generates a conjugate effect in the gradually shrinking throttling channel of the throttling element 30, so that the liquid-phase medium converts potential energy into kinetic energy under the throttling action, that is, the original pressure is converted into speed, the pressure of the sample is reduced, approaching the saturated vapor pressure, and energy conversion occurs. Part of the liquid-phase medium changes from liquid to gas to form a gas-liquid mixed phase, and the formed gas-liquid mixed phase is discharged from the liquid outlet port of the throttling element 30, and then discharged from its outlet end 312 through the liquid separation pipeline 31.

[0048] In the present invention, the flow rate of the liquid-phase medium entering the first gasification unit 2 is adjusted and controlled by using the throttling unit 3, so as to ensure that a part of the liquid-phase medium entering the first gasification unit 2 can match the gasification capacity of the first gasification unit 2 and be completely gasified in the first gasification unit 2. Moreover, through the pressure-reducing flash gasification of the throttling unit 3, most of the liquid-phase medium before entering the first gasification unit 2 remains in a liquid state. After this part of the liquid-phase medium enters the first gasification unit 2, it can ensure that all components contained therein are gasified simultaneously, guaranteeing the authenticity and accuracy of the analysis results.

[0049] Furthermore, in some preferred embodiments of the present invention, as Figure 1 shown, the first gasification unit 2 includes a first heat exchange element 20. The first heat exchange element 20 includes a columnar heat-conducting body 201. A liquid flow channel extending along the length direction of the columnar heat-conducting body 201 is provided inside the columnar heat-conducting body 201. One end of the liquid channel has an opening to form a liquid inlet 202, and the other end of the liquid channel is closed. Among them, a plurality of through holes 203 communicating with the liquid flow channel are provided on the columnar heat-conducting body 201 surrounding the liquid flow channel. A guiding pipe 204 is connected to the outlet of each through hole 203. The liquid-phase medium from the sampling unit 1 enters the liquid flow channel through the liquid inlet 202, and the gas generated by heat gasification passes through the through holes 203 and the guiding pipes 204 and is discharged, and converges at the outlet end 205 of the guiding pipe 204.

[0050] Specifically, the first gasification unit 2 includes a hollow outer shell 21, and the first heat exchange element 20 is arranged inside the hollow outer shell 21. Among them, for the convenience of understanding the structure of the first heat exchange element 20, Figure 1 only the connection of the outlets of some of the through holes 203 to the guiding pipes 204 is shown. When the liquid-phase medium enters the columnar heat-conducting body 201, at least part of the liquid-phase medium is gasified by heat to generate gas. At this time, the gas or gas-liquid mixture enters the through holes 203 and is continuously heated in the through holes 203 and the guiding pipes 204 to be completely gasified. The gas is discharged from the outlet end 205 of the guiding pipe 204 and converges, and then is discharged through the gas outlet 210 provided on the hollow outer shell 21 near the outlet end 205 and enters the analysis unit. Therefore, optionally, the device for sampling and gasifying the liquid-phase medium of the present invention may further include an analysis unit (not shown in the figure) for on-line analyzing the components of the gasified liquid-phase medium. The analysis unit is connected to the gas outlet 210 of the first gasification unit 2 through a pipeline, and the analysis unit includes an on-line chromatograph.

[0051] Among them, both the columnar heat-conducting body 201 and the guiding pipe 204 are made of high heat-conducting materials, such as single substances or alloys such as copper and iron. Among them, the first heat exchange element can adopt electromagnetic induction heating.

[0052] By adopting the above-mentioned honeycomb-shaped first heat exchange element 20, the present invention has a high energy density and a large surface area, which significantly improves the gasification power and efficiency. Among them, a temperature measuring element can be arranged on the first heat exchange element 20, and the temperature of the first gasification unit 2 can be detected in real time through the temperature measuring element. Furthermore, the heating temperature of the first heat exchange element 20 can be adjusted according to the temperature. By controlling the temperature of the first gasification unit 2 above the critical condensation temperature of the liquid phase medium, the liquid phase can be rapidly converted into the gas phase, ensuring that all the liquid phase medium entering it is gasified in a short time, and the state of coexistence of gas and liquid will not occur, effectively avoiding the defect of insufficient gasification and reducing the representativeness of the sample.

[0053] Furthermore, in some preferred embodiments of the present invention, such as Figure 1 and Figure 2 shown, the first pipeline 4 has an inlet end and an outlet end 41. Its inlet end is connected to the sampling probe 10. A nozzle 42 is provided between the outlet end 41 of the first pipeline 4 and the liquid inlet 202. The liquid phase medium enters the liquid flow channel of the first heat exchange element 20 through the nozzle 42. The outlet of the nozzle 42 is of a reduced orifice structure. Among them, the inlet end 211 of the liquid distribution pipeline 31 is connected to the wall of the first pipeline 4 near the outlet end 41 of the first pipeline 4.

[0054] In this embodiment, the cross-sectional area of the nozzle 42 decreases in the direction from the outlet end 41 of the first pipeline 4 to the liquid inlet 202, forming a structure with a liquid phase flow limiting function. On the one hand, this nozzle 42 can avoid the generation of gas-liquid mixing phenomenon. On the other hand, it can specifically set the flow rate of the liquid phase medium entering the first heat exchange element 20 by changing its size. The flow rate of the nozzle 42 is determined according to the pressure of the sampling unit 1, the pressure of the first gasification unit 2, the demand for the liquid phase medium that the first gasification unit 2 can gasify, and the demand of the analysis unit, and a certain margin needs to be reserved. For example, the liquid phase medium is taken out from the liquid phase medium sampling pipeline through the sampling probe 10, and the pressure is P1. The pressure of the gasified gas that the first gasification unit 2 needs to collect is P2. The flow rate of the nozzle 42 is determined according to factors such as the demands of the analysis unit and the first gasification unit 2, P1, P2, etc.

[0055] Furthermore, in some preferred embodiments of the present invention, it further includes a closed vacuum heat insulation shell 5. The sampling unit 1 and the throttling unit 3 are integrated in the vacuum heat insulation shell 5, and the inlet end 101 of the sampling probe 10 is exposed outside the vacuum heat insulation shell 5 for facilitating sample collection.

[0056] In this embodiment, a vacuum chamber is formed inside the vacuum insulation housing 5 for accommodating the sampling unit 1 and the throttling unit 3 and providing a vacuum insulation environment. By forming a vacuum environment inside the vacuum insulation housing 5, it is not only possible to effectively prevent the subcooled liquid phase medium entering the sampling unit 1 and the throttling unit 3 from exchanging heat with the outside world, but also to isolate the cryogenic environment of the sampling unit 1 and the throttling unit 3 from the heating environment of the first vaporization unit 2, preventing cold and heat convection between the above-mentioned units, thereby effectively suppressing the premature vaporization of low-boiling components in the liquid phase medium, ensuring that the liquid phase medium before entering the vaporization unit remains in a liquid state, thus ensuring the acquisition of representative samples and improving the accuracy of the component analysis of the liquid phase medium.

[0057] Furthermore, in some preferred embodiments of the present invention, the vacuum insulation housing 5 is integrally vacuum encapsulated with a heat insulation material on the outside of the sampling unit 1 and the throttling unit 3.

[0058] Among them, the heat insulation material can effectively block heat conduction, heat convection and heat radiation, and play a role in heat insulation and cold preservation. It can include, but is not limited to, aluminum foil, fiberglass paper, fiberglass tape or nanotube materials, etc. Among them, the vacuum chamber of the vacuum insulation housing 5 not only ensures that the temperature of the liquid phase medium in the chamber is basically the same as the sampling point temperature in a vacuum environment with an extremely low heat leakage rate, but also plays a role in absorbing the heat during the transfer of the liquid phase medium. Once the liquid phase medium vaporizes, it can absorb heat and provide a greater degree of supercooling. The vacuum degree of the vacuum insulation housing 5 can be 10 -3 Pa, which can be adjusted according to the actual application environment. In addition, the vacuum insulation housing 5 of the present invention adopts a one-time vacuum encapsulation, which has the advantages of long life and small maintenance volume.

[0059] Furthermore, in some preferred embodiments of the present invention, as Figure 1 shown, at the connection between the first vaporization unit 2 and the nozzle 42, there is a heat insulation structure 400 formed by a heat insulation material to isolate the cryogenic environment of the sampling unit 1 and the throttling unit 3 from the heating environment of the first vaporization unit 2, for preventing cold and heat exchange between the above-mentioned units, thereby effectively suppressing the premature vaporization of low-boiling components in the liquid phase medium. Among them, the heat insulation structure 400 is formed by a heat insulation material into a structure similar to a heat insulation cover and is disposed at the opening of the housing 21 of the first vaporization unit 2, and at least part of the first heat exchange element 20 is wrapped by the heat insulation structure 400.

[0060] Furthermore, in some preferred embodiments of the present invention, a first valve 6 for controlling the on-off of the sampling unit 1 is provided on the first pipeline 4 between the sampling unit 1 and the throttling unit 3.

[0061] In this embodiment, the inlet end 101 of the sampling probe 10 is inserted into the liquid-phase medium sampling pipeline 100. The outlet end of the sampling probe 10 is connected to the inlet end of the first valve 6. The outlet end of the first valve 6 is connected to the nozzle 42 through the first pipeline 4. The liquid-phase medium enters from the inlet end 101 of the sampling probe 10 and enters the first gasification unit 2 through the first valve 6, the first pipeline 4 and the nozzle 42. During the sampling analysis process, the first valve 6 remains open; when the device of the present invention needs to stop sampling for maintenance, the first valve 6 is closed, thereby shutting off the sampling analysis operation.

[0062] Further, in some preferred embodiments of the present invention, the first valve 6 is a cryogenic globe valve. The free end of the valve stem 60 of the cryogenic globe valve is exposed outside the vacuum insulation housing 4. By adjusting the valve stem 60, the opening and closing of the first valve 6 can be conveniently achieved.

[0063] In this embodiment, the cryogenic globe valve can be a manual globe valve or an automatic globe valve, and the automatic globe valve can be opened and closed under the drive of a cylinder or a motor.

[0064] Further, in some preferred embodiments of the present invention, a discharge unit 7 communicating with the throttling unit 3 is further included, which is used to gasify the gas-liquid mixed phase generated by the throttling unit 3 and then transport it to the gas recovery main pipe 8;

[0065] Wherein, the discharge unit 7 includes a second pipeline 70 connecting the outlet end 312 of the liquid separation pipeline 31 and the gas recovery main pipe 8. A second gasification unit 71 for gasifying the gas-liquid mixed phase is provided on the second pipeline 70; wherein, the outlet end 312 of the liquid separation pipeline 31 is close to the sampling unit 1.

[0066] In this embodiment, the outlet end 312 of the liquid separation pipeline 31 is communicated with the second gasification unit 71 through the second pipeline 70. The gas-liquid mixed phase discharged from the throttling element 30 enters the second gasification unit 71 through the outlet end 312 and the second pipeline 70 in sequence, and is gasified into gas under the action of the second gasification unit 71 and then flows into the gas recovery main pipe 8; wherein, the second gasification unit 71 can include the first heat exchange element 20 as described above, and the second gasification unit 71 can also include a gasifier commonly used in the art, which is not limited in the present invention;

[0067] Among them, the inlet end 311 of the liquid separation pipeline 31 is close to the first vaporization unit 2, and the outlet end 312 of the liquid separation pipeline 31 extends from the throttling element 30 towards the sampling unit 1, so that the liquid separation pipeline 31 is completely integrated in the vacuum insulation housing 5; during the flow of the gas-liquid mixed phase in the liquid separation pipeline 31 towards the outlet end 312, kinetic energy is converted into heat energy and continuously vaporized, and heat is absorbed during this process to ensure that the liquid-phase medium in the first pipeline 4 has sufficient cold energy and will not be vaporized before entering the first vaporization unit 2, and can avoid excessive loss of the sample.

[0068] Furthermore, in some preferred embodiments of the present invention, the discharge unit 7 further includes a pressure transmitter 72 and a second valve 73 disposed between the second vaporization unit 71 and the gas recovery main pipe 8; the second valve 73 is a backpressure valve.

[0069] Among them, the pressure transmitter 72 and the second valve 73 are arranged in sequence in the gas flow direction. The pressure transmitter 72 is used to detect the pressure of the gas in the second pipeline 70, and the second valve 73 is used to regulate the pressure of the gas in the second vaporization unit 71.

[0070] In this embodiment, exemplarily, when the liquid-phase medium to be sampled and analyzed is LNG, a small amount of LNG decompression flash vaporization in the throttling unit 3 generates a gas-liquid mixed phase. The gas-liquid mixed phase generates BOG (Boil Off Gas) gas when heated in the second vaporization unit 71. This part of the gas is returned to the BOG main pipe through the discharge unit 7, thereby realizing the recovery of this part of the gas. Among them, when the BOG gas generated in the second vaporization unit 71 absorbs heat, the pressure in the second vaporization unit 71 rises. When the set pressure is reached, the second valve 73 opens, and the BOG gas generated in the second vaporization unit 71 is discharged into the BOG main pipe. The second valve 73 ensures the stability of the pressure in the second vaporization unit 71, and thus can ensure the stability of the pressure in the throttling unit 3.

[0071] Furthermore, in some preferred embodiments of the present invention, an electric heating tape 74 is provided on the second pipeline 70.

[0072] In this embodiment, the electric heating tape 74 is wrapped around the second pipeline 70 between the throttling unit 3 and the gas recovery main pipe 8 to heat the discharged gas, because the discharged gas may carry a small amount of liquid, and the discharged gas is heated to ensure that the medium entering the gas recovery main pipe 8 is in a gaseous state.

[0073] Furthermore, an electric heating tape 74 is also provided on the pipeline connecting the outlet 210 of the analysis unit and the first vaporization unit 2 to ensure that the medium entering the analysis unit is in a gaseous state.

[0074] Further, in some preferred embodiments of the present invention, temperature measuring elements 9 are provided on the first heat exchange element, the first pipeline near the nozzle, and the second pipeline between the throttling unit and the second gasification unit; the temperature measuring elements 9 are used to detect the temperature in real time, wherein the temperature measuring element can be a temperature sensor.

[0075] Further, a temperature measuring element is also provided on the pipeline connecting the analysis unit and the outlet 210 of the first gasification unit 2 to monitor the temperature of the medium entering the analysis unit in real time.

[0076] When the device for sampling and gasifying liquid-phase medium of the present invention is in use, the front end of the sampling unit 1 is connected, through, for example, a flange or other fixing parts, to a sampling pipeline 100 or a container that needs to be subjected to component analysis (such as a liquid-phase medium unloading main pipeline or a tank truck loading main pipeline, etc.); in some ways, a sampling port is provided on the sampling pipeline 100, and the pipe wall of the sampling pipeline 100 around the sampling port bulges outwards to form a short neck 200. The front end of the sampling unit 1 is inserted into the short neck 200 and fixed to the sampling pipeline 100 through a flange 300. Among them, the inlet end 101 of the sampling probe 10 is exposed outside the vacuum heat insulation housing 5 to collect the liquid-phase sample in the sampling pipeline 100. The sample enters the first gasification unit 2 from the inlet end 101 of the sampling probe 10 through the first valve 6 and the nozzle 42 for gasification. Among them, a small amount and a fixed amount of the liquid-phase medium gasify and absorb heat in the throttling unit 3 to increase the subcooling degree of the remaining most of the liquid-phase medium before entering the first gasification unit 2, and prevent the liquid-phase medium before entering the first gasification unit 2 from gasifying in advance.

[0077] The present invention ensures that the enthalpy increment of the liquid-phase medium from the sampling probe 10 to the first gasification unit 2 is less than the subcooling degree of the liquid-phase medium at the inlet end 101 of the sampling probe 10 by setting the throttling unit 3 and the vacuum heat insulation housing 5, so as to ensure that the liquid-phase medium does not fractionate before gasifying in the first gasification unit 2, and ensure that the components of the liquid-phase medium entering the first gasification unit 2 gasify simultaneously; and the present invention heats the liquid-phase medium by using the first heat exchange element 20 with high energy density, so that the components in the liquid-phase medium quickly complete the phase conversion, shorten the gasification time, and further increase the accuracy of the sample analysis result.

[0078] Among them, the heat absorption of the liquid-phase medium during the sampling process is calculated according to the following formula (1) in ISO8943-2007:

[0079]

[0080] In the formula:

[0081] Q - heat absorption, unit W;

[0082] T a— Ambient temperature, unit: K;

[0083] T s — Temperature of the liquid-phase medium, unit: K;

[0084] h a — Heat transfer surface coefficient of the heat insulation material of the vacuum insulation shell, unit: W / m 2 ·K;

[0085] k — Thermal conductivity of the heat insulation material of the vacuum insulation shell, unit: W / m 2 ·K;

[0086] D0 — Outer diameter of the vacuum insulation shell, unit: m;

[0087] D1 — Inner diameter of the vacuum insulation shell, unit: m;

[0088] L — Effective length that the liquid-phase medium flows through from the inlet end of the sampling probe to the outlet end of the throttling vaporization unit, unit: m.

[0089] Among them, the heat absorption during the sampling process refers to the heat absorbed by the liquid-phase medium flowing from the inlet end of the sampling probe to the outlet end of the throttling vaporization unit. In the formula, h a and k are related to the heat insulation material constituting the vacuum insulation shell; D0 and D1 are related to the volume of the vacuum insulation shell and the thickness of the heat insulation material constituting the vacuum insulation shell.

[0090] Among them, the enthalpy increment of the liquid-phase medium during the sampling process is calculated according to the following formula (2):

[0091]

[0092] In the formula, ΔH1 is the enthalpy increment, unit: J / kg; Q is the heat absorption calculated according to formula (1); L is the same as in formula (1); F is the flow rate of the liquid-phase medium, unit: kg / h, which can be obtained by calculating according to the diameter of the sampling probe and the pressure inside the sampling probe.

[0093] Among them, the enthalpy increment during the sampling process refers to the enthalpy increment of the liquid-phase medium flowing from the inlet end of the sampling probe to the outlet end of the throttling vaporization unit.

[0094] Among them, the enthalpy change generated by the phase change in the throttling vaporization unit is calculated according to the following formula (3):

[0095] ΔH2 = mΔvapH m (3)

[0096] In the formula, ΔH2 is the enthalpy change, unit: J / kg; m is the mass of the liquid-phase medium generating the phase change; ΔvapH m is the enthalpy change per kilogram of the liquid-phase medium.

[0097] Based on the above ΔH2, the degree of undercooling generated by the phase change of the liquid-phase medium in the throttling gasification unit can be obtained according to the enthalpy curve in the ISO8943 standard; based on the above ΔH1 and ΔH2, the total enthalpy increment of the liquid-phase medium before entering the gasification unit can be obtained.

[0098] The above description is only a preferred embodiment of the present invention and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present invention.

Claims

1. A device for sampling and gasifying a liquid-phase medium, characterized in that, Comprising: A sampling unit, including a sampling probe, for collecting the liquid-phase medium; A first vaporization unit, for vaporizing the liquid-phase medium collected by the sampling unit; And A throttling unit, disposed on a first pipeline for connecting the sampling unit and the first vaporization unit, configured to regulate the flow rate of the liquid-phase medium entering the first vaporization unit, and based on pressure-reducing vaporization, enabling the liquid-phase medium entering the first vaporization unit to have sufficient supercooling degree, The throttling unit includes a throttling element and a liquid distribution pipeline, and the throttling element is disposed on the liquid distribution pipeline; the throttling element includes a housing, and a liquid inlet and a liquid outlet are provided at opposite ends of the housing, a throttling channel is provided in the housing, and the liquid inlet, the liquid outlet and the throttling channel are in communication with each other; the cross-sectional area of the throttling channel gradually decreases first and then gradually increases in the direction from the liquid inlet to the liquid outlet; wherein, a part of the liquid-phase medium collected by the sampling unit enters the first vaporization unit via the first pipeline, and another part of the liquid-phase medium collected by the sampling unit enters the throttling element via the liquid distribution pipeline communicated with the first pipeline, and after pressure-reducing vaporization, a gas-liquid mixed phase is discharged from the liquid outlet; The first vaporization unit includes a first heat exchange element; the first heat exchange element includes a columnar heat-conducting body, a liquid flow channel extending along the length direction of the columnar heat-conducting body is provided in the columnar heat-conducting body, one end of the liquid flow channel has an opening to form a liquid inlet, and the other end of the liquid flow channel is closed; wherein, a plurality of through holes communicated with the liquid flow channel are provided on the columnar heat-conducting body surrounding the liquid flow channel, and a guiding pipe is connected to the outlet of each through hole; the liquid-phase medium from the sampling unit enters the liquid flow channel via the liquid inlet, the gas generated by heat vaporization is discharged via the through holes and the guiding pipes, and converges at the outlet end of the guiding pipe, wherein, both the columnar heat-conducting body and the guiding pipe are made of high heat-conducting materials.

2. The device for sampling and gasifying a liquid-phase medium according to claim 1, characterized in that, A nozzle is provided between the outlet end of the first pipeline and the liquid inlet, and the liquid-phase medium enters the liquid flow channel via the nozzle, and the outlet of the nozzle is of a constricted structure; wherein, the inlet end of the liquid distribution pipeline is connected to the pipe wall of the first pipeline near the outlet end of the first pipeline.

3. The device for sampling and gasifying a liquid-phase medium according to claim 2, characterized in that, It further includes a closed vacuum heat-insulating outer shell, the sampling unit and the throttling unit are integrated in the vacuum heat-insulating outer shell, and the inlet end of the sampling probe is exposed outside the vacuum heat-insulating outer shell.

4. The device for sampling and gasifying a liquid-phase medium according to claim 3, characterized in that, A first valve for controlling the on-off of the sampling unit is provided on the first pipeline, and the free end of the valve stem of the first valve is exposed outside the vacuum heat-insulating outer shell.

5. The device for sampling and gasifying a liquid-phase medium according to claim 3, characterized in that, It further includes an emission unit communicated with the throttling unit, for vaporizing the gas-liquid mixed phase generated by pressure-reducing vaporization of the throttling unit and transporting it to a gas recovery main pipe; Wherein, the emission unit includes a second pipeline connecting the outlet end of the liquid distribution pipeline and the gas recovery main pipe, and a second vaporization unit for vaporizing the gas-liquid mixed phase is provided on the second pipeline; wherein, the outlet end of the liquid distribution pipeline is close to the sampling unit.

6. The device for sampling and gasifying a liquid-phase medium according to claim 5, characterized in that, The discharge unit further includes a pressure transmitter and a second valve disposed between the second gasification unit and the main gas recovery pipe; the second valve is a back pressure valve.

7. The device for sampling and gasifying a liquid-phase medium according to claim 5, characterized in that, An electric tracing heating band is provided on the second pipeline.

8. The device for sampling and gasifying a liquid-phase medium according to claim 5, characterized in that, Temperature measuring elements are provided on the first heat exchange element, the first pipeline near the nozzle, and the second pipeline between the throttling unit and the second gasification unit.

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