Compact multi-stage heating LNG vaporizer

Abstract

The invention relates to a compact multi-stage heating LNG vaporizer which comprises a first-stage structure, a second-stage structure, a second-stage structure and a third-stage structure, the first-stage structure comprises a first-stage shell and a first-stage spiral pipe, and a first-stage inlet used for introducing a first-stage medium is formed in the first-stage shell; the second-stage structure comprises a second-stage shell and a second-stage spiral pipe, and a second-stage inlet for introducing a second-stage medium is formed in the second-stage shell; the third-stage structure comprises a third-stage shell and a third-stage spiral pipe, and a third-stage inlet for introducing a third-stage medium is formed in the third-stage shell; the temperature of the first-stage medium entering the first-stage inlet, the temperature of the second-stage medium entering the second-stage inlet and the temperature of the third-stage medium entering the third-stage inlet are set from low to high, and the number of the spiral pipes of each group of the first-stage spiral pipes is not equal to the number of the spiral pipes of each group of the second-stage spiral pipes; and the number of the spiral pipes of each group of second-stage spiral pipes is not equal to the number of the spiral pipes of each group of third-stage spiral pipes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of LNG vaporizer, in particular to a compact multi-stage heating LNG vaporizer. BACKGROUND

[0002] Natural gas is a clean and efficient energy, which is gas at room temperature, and is inconvenient to store and transport over long distances, so it is generally converted into low-temperature liquid (LNG) at-161.5℃ or below first, and then stored and transported over long distances, but before using LNG, it is necessary to use a vaporizer to warm the liquid LNG at about-163℃ to gaseous natural gas (NG) at about 5℃.

[0003] The LNG vaporizer is a device specially used for LNG vaporization, and the existing LNG vaporizer has the disadvantages of low cold energy utilization rate, large floor area, and low heat exchange efficiency, so how to design a compact LNG vaporizer with high cold energy utilization rate and high heat exchange efficiency is the goal pursued by those skilled in the art. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a compact multi-stage heating LNG vaporizer.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] A compact multi-stage heating LNG vaporizer, comprising: a first stage structure comprising a first stage shell and a set of and more first stage coils disposed within the first stage shell, the first stage shell having a first stage inlet for passing in a first stage medium and a first stage outlet for outputting the first stage medium; a second stage structure comprising a second stage shell and a set of and more second stage coils disposed within the second stage shell, the second stage shell having a second stage inlet for passing in a second stage medium and a second stage outlet for outputting the second stage medium; a third stage structure comprising a third stage shell and a set of and more third stage coils disposed within the third stage shell, the third stage shell having a third stage inlet for passing in a third stage medium and a third stage outlet for outputting the third stage medium; the temperature of the first stage medium entering the first stage inlet, the temperature of the second stage medium entering the second stage inlet, and the temperature of the third stage medium entering the third stage inlet being arranged from low to high, each set of the first stage coils, each set of the second stage coils, and each set of the third stage coils each comprising one and more coils and each being used for passing natural gas, and the number of coils in each set of the first stage coils being arranged unequally to the number of coils in each set of the second stage coils, the number of coils in each set of the second stage coils being arranged unequally to the number of coils in each set of the third stage coils, the first stage shell, the second stage shell, and the third stage shell being arranged in sequence, a first transition cavity being arranged between the first stage shell and the second stage shell, and a second transition cavity being arranged between the second stage shell and the third stage shell.

[0007] In an embodiment, the rear end of the first stage coils penetrates the first transition cavity, the front end of the second stage coils penetrates the first transition cavity, the rear end of the second stage coils penetrates the second transition cavity, and the front end of the third stage coils penetrates the second transition cavity.

[0008] In an embodiment, the first stage shell comprises a first stage outlet tube sheet, the second stage shell comprises a second stage inlet tube sheet, the second stage shell comprises a second stage outlet tube sheet, and the third stage shell comprises a third stage inlet tube sheet, the first stage outlet tube sheet and the second stage inlet tube sheet enclosing the first transition cavity, and the second stage outlet tube sheet and the third stage inlet tube sheet enclosing the second transition cavity.

[0009] In an embodiment, the first stage coils are installed on the first stage outlet tube sheet through first stage tube bundle positioning holes, and / or the second stage coils are installed on the second stage outlet tube sheet and the second stage inlet tube sheet through second stage tube bundle positioning holes, and / or the third stage coils are installed on the third stage outlet tube sheet and the third stage inlet tube sheet through third stage tube bundle positioning holes.

[0010] In an embodiment, the first-stage pipe bundle positioning hole is a double-circle hole arranged at intervals, and / or the second-stage pipe bundle positioning hole is a three-circle hole arranged at intervals, and the center lines of the three circles form an equilateral triangle, and / or the third-stage pipe bundle positioning hole is a single-circle hole.

[0011] In an embodiment, each group of the first-stage spiral pipe is formed by winding two of the spiral pipes, and / or each group of the second-stage spiral pipe is formed by winding three of the spiral pipes, and / or each group of the third-stage spiral pipe is formed by a single spiral pipe.

[0012] In an embodiment, the first-stage medium is one of ethylene, propane and ethanol, and / or the second-stage medium is one of gaseous carbon dioxide and industrial waste heat steam, and / or the third-stage medium is one of seawater and air.

[0013] In an embodiment, the temperature of the first-stage medium entering the first-stage inlet ranges from -95℃ to -85℃, the temperature of the second-stage medium entering the second-stage inlet ranges from 5℃ to 15℃, and the temperature of the third-stage medium entering the third-stage inlet ranges from 20℃ to 30℃.

[0014] In an embodiment, the temperature of the natural gas entering the first-stage structure ranges from -170℃ to -160℃, the temperature of the natural gas leaving the first-stage structure ranges from -120℃ to -100℃, and / or the temperature of the natural gas entering the second-stage structure ranges from -120℃ to -100℃, the temperature of the natural gas leaving the second-stage structure ranges from -45℃ to -35℃, and / or the temperature of the natural gas entering the third-stage structure ranges from -45℃ to -35℃, and the temperature of the natural gas leaving the third-stage structure ranges from 0℃ to 20℃.

[0015] In an embodiment, the tail of the first-stage spiral pipe, the tail of the second-stage spiral pipe and the tail of the third-stage spiral pipe are each provided with a temperature sensor, and the temperature sensor is electrically connected to a PID controller, thereby controlling the temperature of the natural gas in the first-stage structure, the second-stage structure and the third-stage structure, respectively.

[0016] In an embodiment, a super-hydrophobic material is applied to the outside of the first-stage spiral pipe, and an array of ultrasonic transducers is fixedly arranged outside the first-stage spiral pipe, and / or a super-hydrophobic material is applied to the outside of the second-stage spiral pipe, and an array of ultrasonic transducers is fixedly arranged outside the second-stage spiral pipe.

[0017] Thanks to the above technical solution, the present application has the following advantages compared with the prior art:

[0018] a. The compact multi-stage heating LNG vaporizer of the present application realizes heat exchange between LNG and multiple media through the setting of a three-stage structure, and through layer-by-layer grading, can realize efficient recovery and comprehensive utilization of cold energy;

[0019] b. The compact multi-stage heating LNG vaporizer of the present application, by setting one or more than one spiral pipe for each group of spiral pipes, greatly increases the unit volume heat exchange area compared with single pipe, greatly reduces the equipment volume, and is more compact in structure;

[0020] c. The compact multi-stage heating LNG vaporizer of the present application, by setting adjacent three-stage spiral pipes of different numbers, adjusts the heat exchange area of natural gas according to the difference of the media used in each stage, reduces the number of spiral pipes under the premise of ensuring the heat exchange effect, and saves the manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a perspective view of the compact multi-stage heating LNG vaporizer in an embodiment of the present application;

[0022] Figure 2 is a side view of the compact multi-stage heating LNG vaporizer in an embodiment of the present application with the three-stage shell removed;

[0023] Figure 3 is a side view of the first-stage spiral pipe in an embodiment of the present application;

[0024] Figure 4 is a side view of the second-stage spiral pipe in an embodiment of the present application;

[0025] Figure 5 is a front view of the first-stage spiral pipe in an embodiment of the present application;

[0026] Figure 6 is a front view of the second-stage spiral pipe in an embodiment of the present application;

[0027] Figure 7 is a front view of the first-stage outlet pipe plate or the first-stage inlet pipe plate in an embodiment of the present application;

[0028] Figure 8 is a front view of the second-stage outlet pipe plate or the second-stage inlet pipe plate in an embodiment of the present application;

[0029] In the drawings:

[0030] 1 - natural gas inlet part; 11 - natural gas inlet body; 12 - natural gas inlet pipe; 2 - first stage structure; 21 - first stage shell; 22 - first stage spiral pipe; 23 - first stage inlet; 24 - first stage outlet; 211 - first stage inlet pipe plate; 212 - first stage outlet pipe plate; 27 - first stage tube bundle positioning hole; 3 - second stage structure; 31 - second stage shell; 32 - second stage spiral pipe; 33 - second stage inlet; 34 - second stage outlet; 311 - second stage inlet pipe plate; 312 - second stage outlet pipe plate; 37 - second stage tube bundle positioning hole; 4 - third stage structure; 41 - third stage shell; 42 - third stage spiral pipe; 43 - third stage inlet; 44 - third stage outlet; 411 - third stage inlet pipe plate; 412 - third stage outlet pipe plate; 5 - natural gas outlet part; 51 - natural gas outlet body; 52 - natural gas outlet pipe; 6 - ultrasonic transducer array; 7 - temperature sensor; 8 - first transition cavity; 9 - second transition cavity. DETAILED DESCRIPTION

[0031] The application will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0032] Referring to Figures 1-8 The compact multi-stage heating LNG vaporizer of the present application includes a natural gas inlet part 1, a first stage structure 2, a second stage structure 3, a third stage structure 4, and a natural gas outlet part 5.

[0033] The natural gas inlet part 1 includes a natural gas inlet body 11 in the shape of a hemisphere, and a natural gas inlet pipe 12 passing through the inside of the natural gas inlet body 11.

[0034] The first stage structure 2 includes a first stage shell 21 and a set of one or more first stage spiral pipes 22 arranged in the first stage shell 21, and the first stage shell 21 is provided with a first stage inlet 23 for the passage of a first stage medium and a first stage outlet 24 for the output of the first stage medium. Specifically, the first stage shell 21 is in the shape of a cylinder, and the front end portion thereof is provided with a first stage inlet pipe plate 211, and the rear end portion thereof is provided with a first stage outlet pipe plate 212. The first stage inlet pipe plate 211 is fixedly connected to the natural gas inlet body 11, and the space between the two forms a space for storing natural gas. In an embodiment, the first stage inlet 23 is arranged with its opening facing upward, and is arranged above the first stage shell 21, and the first stage outlet 24 is arranged with its opening facing downward, and is arranged below the first stage shell 21.

[0035] The second-stage structure 3 comprises a second-stage shell 31 and a group of second-stage spiral pipes 32 arranged in the second-stage shell 31, and the second-stage shell 31 is provided with a second-stage inlet 33 for the second-stage medium and a second-stage outlet 34 for outputting the second-stage medium, and specifically, the second-stage shell 31 is in a cylindrical shape, the front end of which is provided with a second-stage inlet pipe plate 311, and the rear end of which is provided with a second-stage outlet pipe plate 312, and the first-stage outlet pipe plate 212 is fixedly connected with the second-stage inlet pipe plate 311, and the two plates surround to form a first transition cavity 8 for containing natural gas. In an embodiment, the second-stage inlet 33 is upwardly arranged, and is arranged above the second-stage shell 31, and the second-stage outlet 34 is downwardly arranged, and is arranged below the second-stage shell 31.

[0036] The third-stage structure 4 comprises a third-stage shell 41 and a group of third-stage spiral pipes 42 arranged in the third-stage shell 41, and the third-stage shell 41 is provided with a third-stage inlet 43 for the third-stage medium and a third-stage outlet 44 for outputting the third-stage medium, and specifically, the third-stage shell 41 is in a cylindrical shape, the front end of which is provided with a third-stage inlet pipe plate 411, and the rear end of which is provided with a third-stage outlet pipe plate 412, and the second-stage outlet pipe plate 312 is fixedly connected with the third-stage inlet pipe plate 411, and the two plates surround to form a second transition cavity 9 for containing natural gas. In an embodiment, the third-stage inlet 43 is upwardly arranged, and is arranged above the third-stage shell 41, and the third-stage outlet 44 is downwardly arranged, and is arranged below the third-stage shell 41.

[0037] The natural gas outlet part 5 comprises a natural gas outlet body 51 in a hemispherical shape and a natural gas outlet pipe 52 penetrating through the inside of the natural gas outlet body 51.

[0038] Each group of first-stage spiral pipes 22, each group of second-stage spiral pipes 32 and each group of third-stage spiral pipes 42 are composed of one or more spiral pipes and are used for passing natural gas, and the number of spiral pipes in each group of first-stage spiral pipes 22 is not equal to the number of spiral pipes in each group of second-stage spiral pipes 32, and the number of spiral pipes in each group of second-stage spiral pipes 32 is not equal to the number of spiral pipes in each group of third-stage spiral pipes 42, and in an embodiment, as shown in FIG. 2, each group of first-stage spiral pipes 22 is formed by two spiral pipes, and as shown in FIG. 3, each group of second-stage spiral pipes 32 is formed by three spiral pipes, and as shown in FIG. 4, each group of third-stage spiral pipes 42 is formed by two spiral pipes. Figure 3 Figure 4 ​As shown, each group of second-stage spiral pipes 32 is formed by three spiral pipes, and each group of third-stage spiral pipes 42 is formed by a single spiral pipe. The rear end of the first-stage spiral pipe 22 penetrates the first transition cavity 8, the front end of the second-stage spiral pipe 32 penetrates the first transition cavity 8, the rear end of the second-stage spiral pipe 32 penetrates the second transition cavity 9, and the front end of the third-stage spiral pipe 42 penetrates the second transition cavity 9. The first-stage spiral pipe 22 is installed on the first-stage outlet pipe plate 212 and the first-stage inlet pipe plate 211 through the first-stage pipe bundle positioning hole 27, the second-stage spiral pipe 32 is installed on the second-stage outlet pipe plate 312 and the second-stage inlet pipe plate 311 through the second-stage pipe bundle positioning hole 37, and the third-stage spiral pipe 42 is installed on the third-stage outlet pipe plate 412 and the third-stage inlet pipe plate 411 through the third-stage pipe bundle positioning hole (not shown in the figure). Specifically, the first-stage spiral pipe 22 is matched with the first-stage pipe bundle positioning hole 27 through an expansion bushing (not shown in the figure), which is inserted into the first-stage pipe bundle positioning hole 27 at low temperature and expanded at high temperature to achieve interference fit. Similarly, the second-stage spiral pipe 32 and the third-stage spiral pipe 42 can also be matched with the second-stage pipe bundle positioning hole 37 and the third-stage pipe bundle positioning hole (not shown in the figure) in the same way. Figure 7 As shown, when the first-stage spiral pipe 22 is formed by two spiral pipes, the first-stage pipe bundle positioning hole 27 is a double circular hole arranged at intervals. Figure 8 As shown, when the second-stage spiral pipe 32 is formed by three spiral pipes, the second-stage pipe bundle positioning hole 37 is a three-circular hole arranged at intervals, and the center lines of the three circular holes form an equilateral triangle. When the third-stage spiral pipe 42 is formed by a single spiral pipe, the third-stage pipe bundle positioning hole is a single circular hole.

[0039] The first-stage medium is one of ethylene, propane, and ethanol, the second-stage medium is one of gaseous carbon dioxide and industrial waste heat steam, and the third-stage medium is one of seawater and air.

[0040] The temperature of the first-stage medium entering the first-stage inlet 23, the temperature of the second-stage medium entering the second-stage inlet 33, and the temperature of the third-stage medium entering the third-stage inlet 43 are arranged from low to high. Specifically, the temperature of the first-stage medium entering the first-stage inlet 23 ranges from -95℃ to -85℃, the temperature of the second-stage medium entering the second-stage inlet 33 ranges from 5℃ to 15℃, and the temperature of the third-stage medium entering the third-stage inlet 43 ranges from 20℃ to 30℃.

[0041] The temperature range of natural gas entering the first stage structure 2 is -170℃ to -160℃, the temperature range of natural gas leaving the first stage structure 2 is -120℃ to -100℃, the temperature range of natural gas entering the second stage structure 3 is -120℃ to -100℃, the temperature range of natural gas leaving the second stage structure 3 is -45℃ to -35℃, and the temperature range of natural gas entering the third stage structure 4 is -45℃ to -35℃, and the temperature range of natural gas leaving the third stage structure 4 is 0℃ to 20℃.

[0042] Specifically, in an embodiment, the first stage medium is ethylene, the second stage medium is gaseous carbon dioxide, and the third stage medium is seawater, the temperature of the first stage medium entering the first stage inlet 23 is -90℃, the temperature of the second stage medium entering the second stage inlet 33 is 10℃, the temperature of the third stage medium entering the third stage inlet 43 is 25℃, the temperature of natural gas entering the first stage structure 2 is -162℃, the temperature range of natural gas leaving the first stage structure 2 is -120℃ to -100℃, the temperature range of natural gas entering the second stage structure 3 is -120℃ to -100℃, the temperature of LNG leaving the second stage structure 3 is -40℃, the temperature of natural gas entering the third stage structure 4 is -40℃, and the temperature range of natural gas leaving the third stage structure 4 is 0℃ to 20℃.

[0043] In an embodiment, a super-hydrophobic material is applied to the outside of the first stage spiral pipe 22, and the ultrasonic transducer array 6 is fixedly arranged outside the first stage spiral pipe 22, a super-hydrophobic material is applied to the outside of the second stage spiral pipe 32, and the ultrasonic transducer array 6 is fixedly arranged outside the second stage spiral pipe. The low surface energy characteristics of the hydrophobic coating reduce the adhesion of liquid droplets to the surface, making it easier for liquid droplets to be driven away by ultrasonic vibration. Specifically, the ultrasonic transducer array 6 can be arranged at the front end of the first stage spiral pipe 22 and the front end of the second stage spiral pipe 32.

[0044] In an embodiment, the rear end of the first stage spiral pipe 22, the rear end of the second stage spiral pipe 32, and the rear end of the third stage spiral pipe 43 are each provided with a temperature sensor 7, which is electrically connected to a PID controller (not shown in the figure), thereby respectively controlling the temperature of natural gas in the first stage structure 2, the second stage structure 3, and the third stage structure 4. That is, the temperature sensor 7 in each stage structure cooperates with the PID controller to achieve precise control of the cascade utilization of cold energy through real-time monitoring and dynamic adjustment.

[0045] Specifically, for the first stage structure 2, the PID controller can adjust the recovery efficiency and stability of high-grade cold energy according to the monitored temperature. If the temperature in the first stage structure 2 is too high, the PID controller is triggered to increase the flow rate of LNG to enhance cold energy extraction. If the temperature in the first stage structure 2 is too low, the flow rate of the first stage medium is adjusted to prevent frost formation in the pipeline caused by excessively low temperature.

[0046] Specifically, for the second level structure 3, the PID controller can regulate the distribution and utilization efficiency of the medium-grade cold energy according to the monitored temperature, and optimize the operation of the second medium trapping system. If the second level temperature is too high, the natural gas temperature in the spiral pipe is reduced by reducing the second medium flow. Similarly, if the second level temperature is too low, the natural gas temperature in the spiral pipe is increased by increasing the second medium flow.

[0047] Specifically, for the third level structure 4, the PID controller can monitor the final LNG gasification outlet temperature and low-grade cold energy recovery efficiency according to the monitored temperature. If the temperature is too high, the third medium pump speed is increased to increase the third medium flow to enhance cooling, and if the temperature is too low, the heater can be started to make the natural gas reach the vaporization standard.

[0048] The working principle of the compact multi-stage heating LNG vaporizer in an embodiment of the present application is described as follows:

[0049] When running, the liquid natural gas LNG enters the natural gas inlet body 11 from the natural gas inlet pipe 12 and then enters the first level spiral pipe 22 to exchange heat with ethylene in counterflow, and the first level outlet 24 is connected to the superconducting cooling loop to realize efficient recovery of ultra-low temperature cold energy of-162℃ to-120℃. After heat exchange, the LNG flows into the first transition cavity 8 to avoid the risk of liquid impact in the passage. Then the LNG enters the second level spiral pipe 32 to exchange heat with pressurized gaseous CO2, and the second level outlet 34 is directly connected to the liquefied storage unit of the CO2 trapping system to realize directional capture of medium-grade cold energy of-100℃ to-40℃. After heat exchange, the natural gas passes through the second transition cavity 9 to prevent the occurrence of passage gas blockage. Finally, the natural gas enters the third level spiral pipe 42 and realizes low-grade cold energy recovery of-40℃ to 10℃ using the third medium seawater. And cooperate with the PID controller to dynamically adjust the temperature of the natural gas in the first level structure 2, the second level structure 3 and the third level structure 4 according to the monitored temperature.

[0050] In an embodiment, the compact multi-stage heating LNG vaporizer of the present application has the following technical effects:

[0051] 1. The compact multi-stage heating LNG vaporizer can realize efficient recovery and comprehensive utilization of cold energy through layer-by-layer grading. The cold energy is captured in stages, the high-grade cold energy is captured by the ethylene closed-loop system for superconducting device cooling, the medium-grade cold energy is used to drive the absorption chiller set or the CO2 trapping system, and the low-grade cold energy is absorbed by seawater for pre-cooling industrial circulating water or cold energy power generation. The LNG vaporizer is made of three shells in series, which is more compact in structure. Each end of each level is provided with a transition cavity, which can effectively suppress the flow pulsation and shock fluctuation of gas-liquid two-phase flow during heat exchange, prevent the occurrence of intermittent gas blockage, and thus ensure the stability of flow and the continuity of system operation.

[0052] 2. The compact multi-stage heating LNG vaporizer adopts the multi-strand spiral pipe parallel winding technology, the spiral curvature radius of the multi-strand spiral pipe is smaller, and stronger Dean vortex (secondary flow) is generated due to the centrifugal force when the fluid flows through the spiral channel, the laminar boundary layer is destroyed, and the turbulence intensity is significantly improved. The multi-strand spiral pipe is arranged in a honeycomb shape, the heat exchange area per unit volume is greatly improved compared with a single spiral pipe, and the equipment volume is greatly reduced. The multi-strand spiral structure uniformly distributes the fluid to the corresponding independent flow channel, avoids the flow dead zone easily occurring in the single spiral pipe, and greatly reduces the standard deviation of temperature distribution uniformity. The first stage is an ethylene section, a double-pipe spiral is adopted, the heat exchange area and pressure drop control are considered, and the structure is simplified. The second stage is a gaseous CO2 section, three pipes are arranged in parallel. The third stage is a seawater section, a single pipe is used.

[0053] 3. The compact multi-stage heating LNG vaporizer adopts a shape memory alloy (Ni-Ti) to manufacture an expanded bushing, which is inserted into a tube plate hole at low temperature, and expands to realize interference fit after being heated. The expanded force is dynamically adjusted when the temperature changes, and the thermal stress is compensated. After being cooled, the expanded bushing shrinks, and is convenient to disassemble. At the same time, the shells are connected through bolt flanges, and independent modules are formed between the levels, which can be quickly disassembled and assembled, and are convenient for modular maintenance.

[0054] 4. The compact multi-stage heating LNG vaporizer applies temperature sensors at the tail of each spiral pipe, each temperature sensor cooperates with a PID controller to automatically adjust the pump speed or valve opening degree through real-time monitoring and dynamic adjustment, so as to ensure that the temperature difference is stably in an optimal interval (for example, the LNG vaporization temperature difference is controlled to be 70-100 DEG C), and local overcooling or overheating is avoided.

[0055] 5. The compact multi-stage heating LNG vaporizer adopts an ultrasonic vibration-hydrophobic coating cooperative defrosting technology. An ultrahydrophobic material is applied outside the first and second spiral pipes, an ultrasonic vibrator array is fixed on the outer wall of the spiral pipe, the low surface energy characteristic of the hydrophobic coating reduces the adhesion of liquid drops to the surface, so that the liquid drops are more easily driven away by ultrasonic vibration. The drag reduction effect of the hydrophobic surface and the mechanical vibration effect of the ultrasonic wave are coupled, so that the condensed liquid drops on the working surface can be efficiently and quickly removed, and the formation of subsequent frost crystals is hindered on the basis of minimum energy consumption.

[0056] In the description of the present application, the directions such as "front", "back", "left", "right", "up", "down" and the like are defined with reference for the convenience of description, that is, as shown in the drawings. Figure 2As shown, the left side direction in the figure is "front", the right side direction in the figure is "rear", the upper side direction in the figure is "up", the lower side direction in the figure is "down", the direction perpendicular to the view angle in the figure is "left" and "right", the definition of the above directions is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0057] The above examples are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable the person skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A compact multi-stage heating LNG vaporizer characterized by, The application relates to a natural gas heat exchanger, comprising: a first-stage structure comprising a first-stage shell and a group of first-stage spiral tubes arranged in the first-stage shell, the first-stage shell being provided with a first-stage inlet for feeding a first-stage medium and a first-stage outlet for discharging the first-stage medium; a second-stage structure comprising a second-stage shell and a group of second-stage spiral tubes arranged in the second-stage shell, the second-stage shell being provided with a second-stage inlet for feeding a second-stage medium and a second-stage outlet for discharging the second-stage medium; a third-stage structure comprising a third-stage shell and a group of third-stage spiral tubes arranged in the third-stage shell, the third-stage shell being provided with a third-stage inlet for feeding a third-stage medium and a third-stage outlet for discharging the third-stage medium; the temperature of the first-stage medium entering the first-stage inlet, the temperature of the second-stage medium entering the second-stage inlet and the temperature of the third-stage medium entering the third-stage inlet are arranged from low to high, each group of the first-stage spiral tubes, each group of the second-stage spiral tubes and each group of the third-stage spiral tubes are composed of one or more spiral tubes and are used for feeding natural gas, the number of spiral tubes in each group of the first-stage spiral tubes is not equal to the number of spiral tubes in each group of the second-stage spiral tubes, and the number of spiral tubes in each group of the second-stage spiral tubes is not equal to the number of spiral tubes in each group of the third-stage spiral tubes, the first-stage shell, the second-stage shell and the third-stage shell are sequentially arranged, a first transition cavity is arranged between the first-stage shell and the second-stage shell, and a second transition cavity is arranged between the second-stage shell and the third-stage shell.

2. The compact multi-stage heating LNG vaporizer of claim 1, wherein: The rear end of the first-stage spiral tube is penetrated through the first transition cavity, the front end of the second-stage spiral tube is penetrated through the first transition cavity, the rear end of the second-stage spiral tube is penetrated through the second transition cavity, and the front end of the third-stage spiral tube is penetrated through the second transition cavity.

3. The compact multi-stage heating LNG vaporizer of claim 2, wherein: The first-stage shell comprises a first-stage outlet tube plate, the second-stage shell comprises a second-stage inlet tube plate, the second-stage shell comprises a second-stage outlet tube plate, and the third-stage shell comprises a third-stage inlet tube plate, the first-stage outlet tube plate and the second-stage inlet tube plate surround to form the first transition cavity, and the second-stage outlet tube plate and the third-stage inlet tube plate surround to form the second transition cavity.

4. The compact multi-stage heating LNG vaporizer of claim 3, wherein: The first-stage spiral tube is installed on the first-stage outlet tube plate through first-stage tube bundle positioning holes, and / or the second-stage spiral tube is installed on the second-stage outlet tube plate and the second-stage inlet tube plate through second-stage tube bundle positioning holes, and / or the third-stage spiral tube is installed on the third-stage outlet tube plate and the third-stage inlet tube plate through third-stage tube bundle positioning holes.

5. The compact multi-stage heating LNG vaporizer of claim 4, wherein: The first-stage tube bundle positioning holes are double-circle holes arranged at intervals, and / or the second-stage tube bundle positioning holes are three-circle holes arranged at intervals, and the center lines of the three circles form an equilateral triangle, and / or the third-stage tube bundle positioning holes are single-circle holes.

6. The compact multi-stage heated LNG vaporizer of claim 2, wherein: Each group of the first-stage spiral pipe is formed by two of the spiral pipes, and / or each group of the second-stage spiral pipe is formed by three of the spiral pipes, and / or each group of the third-stage spiral pipe is formed by a single one of the spiral pipes.

7. The compact multi-stage heated LNG vaporizer of any of claims 1-6, wherein: The first-stage medium is one of ethylene, propane and ethanol, and / or the second-stage medium is one of gaseous carbon dioxide and industrial waste heat steam, and / or the third-stage medium is one of seawater and air.

8. The compact multi-stage heated LNG vaporizer of any of claims 1-6, wherein: The first-stage medium entering the first-stage inlet has a temperature range of -95℃ to -85℃, the second-stage medium entering the second-stage inlet has a temperature range of 5℃ to 15℃, and the third-stage medium entering the third-stage inlet has a temperature range of 20℃ to 30℃.

9. The compact multi-stage heated LNG vaporizer of any of claims 1-6, wherein: The natural gas entering the first-stage structure has a temperature range of -170℃ to -160℃, the natural gas leaving the first-stage structure has a temperature range of -120℃ to -100℃, the natural gas entering the second-stage structure has a temperature range of -120℃ to -100℃, the natural gas leaving the second-stage structure has a temperature range of -45℃ to -35℃, and the natural gas entering the third-stage structure has a temperature range of -45℃ to -35℃, and the natural gas leaving the third-stage structure has a temperature range of 0℃ to 20℃.

10. The compact multi-stage heated LNG vaporizer of claim 9, wherein: The tail of the first-stage spiral pipe, the tail of the second-stage spiral pipe and the tail of the third-stage spiral pipe are each provided with a temperature sensor, which is electrically connected to a PID controller, thereby controlling the temperature of the natural gas in the first-stage structure, the second-stage structure and the third-stage structure, respectively.

11. The compact multi-stage heated LNG vaporizer of claim 9, wherein: An ultrahydrophobic material is applied to the outside of the first-stage spiral pipe, and an array of ultrasonic transducers is fixedly arranged outside the first-stage spiral pipe, and / or an ultrahydrophobic material is applied to the outside of the second-stage spiral pipe, and an array of ultrasonic transducers is fixedly arranged outside the second-stage spiral pipe.

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