CN111692524A - LNG regasification experimental system and experimental method - Google Patents

Abstract

The invention relates to an LNG re-vaporization experiment system, comprising an LNG circulation unit, wherein the LNG circulation unit comprises an LNG liquid tank, a liquid outlet valve, a plunger type booster pump, a pressure stabilization tank, a microchannel vaporizer, a back pressure valve, Air-temperature reheater, exhaust pipe, three-way valve I, pressure reducing valve, liquid storage tank; a propane circulation unit, the propane circulation unit includes a propane liquid storage tank, a propane circulation pump, three-way valve II, float A coil type heat exchanger, an electric heater, a liquid inlet valve, and a discharge valve; and a test method based on the above-mentioned test system, including the following steps: system construction, propane cooling, LNG vaporization, flow control, and LNG reheating. The advantages of the invention are: by adding a propane circulation unit, the direct heat exchange between propane and LNG fluid is avoided, and at the same time, a large amount of latent heat is released by using the phase change heat of propane, which effectively reduces the occurrence of icing during the heat exchange process of the microchannel vaporizer, Ensure efficient operation of microchannel vaporizers.

Description

A kind of LNG re-vaporization experiment system and experiment method

technical field

The invention relates to an LNG re-vaporization experiment system, and also relates to an experiment method of the above-mentioned experiment system.

Background technique

Cryogenic fluids generally refer to fluids with a temperature range of -40.15°C to -196.15°C. Usually, industrial gases such as LNG, liquid oxygen, liquid hydrogen, liquid nitrogen, and liquid carbon dioxide need to be stored and transported in liquid form, and then re-vaporized at the terminal for use. For LNG re-vaporization, since the volume of LNG is only 1/600 of the volume of natural gas (NG), NG usually needs to be liquefied and then vaporized to meet the requirements of storage and long-distance transportation. However, the critical temperature of LNG is -163°C, which is easy to cause the phenomenon that the heat exchange medium freezes or the vaporization is incomplete during the vaporization process.

The LNG fluid re-vaporization system using the medium-temperature medium circuit avoids the direct heat exchange between the heat source and the LNG. The heat of the heat source is indirectly transferred to the LNG through the medium-temperature medium, which can fully meet the requirements of its re-vaporization and is easy to use according to different working conditions. Controls the amount of vaporization.

The application number is 201280010015.5 and the invention patent titled "Liquid gas re-vaporization device and re-vaporization gas manufacturing method" discloses a system and method for re-vaporization of low-temperature liquefied gas. In this system, the liquefied gas first flows through the preheating heat exchanger, exchanges heat with the first heat exchanger, and then flows into the preheating heat exchanger as a heat source to exchange heat with the incoming low-temperature liquefied gas, and then enters the second heat exchanger. The heat exchanger is used for re-vaporization. However, using the preheated liquefied gas after the first heating to flow the low-temperature liquefied gas cannot significantly increase the temperature of the liquefied gas. The heat transfer of liquefied gas is only through temperature difference, so energy is wasted to a certain extent. In addition, in the first heat exchanger, the low-temperature liquefied gas directly exchanges heat with water or seawater to avoid the problem of freezing, which affects the heat exchange effect, thereby reducing the operating efficiency of the system as a whole.

The application number is 201710014179.X, and the invention patent named "LNG re-vaporization system" discloses a LNG re-vaporization system, which uses seawater as a heat source, exchanges heat with seawater three times through an intermediate medium, and then transfers the heat to LNG At the same time, the expander is driven to generate electricity to achieve the purpose of generating electricity and re-vaporizing LNG. However, the system achieves LNG re-vaporization through multiple heat exchanges, resulting in a complex system structure, huge seawater flow required, and high water pump energy consumption. In addition, the NG outlet temperature of the system cannot meet the usage requirements, and it needs to be heated up again to meet the usage requirements.

The application number is 201811354132.9, and the invention patent titled "A cryogenic supercritical fluid regasification experimental system and working method" discloses a regasification system suitable for a variety of cryogenic supercritical fluids. The system uses hot water As a heat source, heat is exchanged with cryogenic supercritical fluid through a medium temperature medium. Although the structure is simplified, when hot water flows through the floating coil type heat exchanger, it is easy to cause scale to form in the coil and thus affect the heat exchange efficiency, and the scale in the coil is difficult to clean, which brings a lot to the later work. troubled.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an LNG re-vaporization experimental system with a simple structure and efficient operation, and a test method based on the above-mentioned LNG re-vaporization experimental system.

In order to solve the above-mentioned technical problems, the technical scheme of the present invention is as follows: an experimental system for LNG re-vaporization, the innovation of which is: comprising:

An LNG circulation unit, the LNG circulation unit includes an LNG liquid tank, a liquid outlet valve, a plunger booster pump, a pressure stabilization tank, a microchannel vaporizer, a back pressure valve, an air temperature reheater, an emptying pipe, three Through valve I, pressure reducing valve, liquid storage tank, among which, LNG liquid tank, liquid outlet valve, plunger type booster pump, pressure stabilizer tank, micro-channel vaporizer, back pressure valve, air temperature reheater, three-way The valve I, the pressure reducing valve and the liquid storage tank are connected in sequence through pipelines, and the remaining outlet of the three-way valve I is connected with the emptying pipe;

A propane circulation unit, the propane circulation unit includes a propane liquid storage tank, a propane circulation pump, a three-way valve II, a floating coil type heat exchanger, an electric heater, a liquid inlet valve, and a discharge valve, wherein the propane liquid storage tank The tank, the propane circulating pump, the three-way valve II, and the floating coil type heat exchanger are connected by pipelines in sequence, and the inlet of the propane liquid storage tank is connected with the outlet of the microchannel vaporizer, and the outlet of the floating coil type heat exchanger is connected to the outlet of the microchannel vaporizer. The inlet of the micro-channel vaporizer is connected, and the remaining outlet of the three-way valve II is connected to the pipeline connecting the propane liquid storage tank and the micro-channel vaporizer through a pipeline. on the heat exchanger.

Further, the micro-channel vaporizer includes a vaporizer core body, the vaporizer core body is a hollow cuboid structure, and an LNG flow channel group and a propane flow channel group are installed in the inner cavity of the vaporizer core body, and the LNG flow channel group is installed. The propane flow channel group and the propane flow channel group have several groups, which are distributed in the vaporizer core from top to bottom, and the LNG flow channel group and the propane flow channel group are arranged at intervals in turn. The LNG flow channels are arranged horizontally in the direction, and the LNG flow channels extend along the long axis direction of the vaporizer core. The propane flow channel group is composed of several propane flow channels horizontally arranged along the long axis direction of the vaporizer core. And the propane flow channel extends along the width direction of the vaporizer core body, and there are an LNG liquid inlet cavity and an LNG liquid liquid outlet cavity connected to the same side end of each LNG flow channel on both sides of the long axis direction of the vaporizer core body, respectively. There are a propane liquid inlet cavity and a propane liquid outlet cavity connected to the same side end of each propane flow channel on both sides in the width direction of the core body of the vaporizer, and a flow guide plate is also arranged in the propane liquid inlet cavity.

Further, the microchannel vaporizer is a compact and efficient microchannel vaporizer manufactured based on 3D printing technology.

Further, the height of the LNG liquid storage tank is higher than that of the plunger type booster pump.

Further, the relief valve is arranged at the lowest point of the floating coil heat exchanger.

A test method for LNG re-vaporization, the innovation of which is: comprising the following steps

S1 system construction: connect the components that constitute the LNG circulation unit and the components that constitute the propane circulation unit through pipelines, and connect the LNG circulation unit and the propane circulation unit together to form an LNG re-vaporization experimental system;

S2 propane cooling: First, inject cold water into the floating coil heat exchanger, and then use the electric heater to heat the cold water in the floating coil heat exchanger, and then, the liquid propane in the propane storage tank is circulated through the propane The pump increases the pressure so that the pressure reaches 0.36MPa, and then it is sent to the floating coil type heat exchanger through the three-way valve II, and the hot water in the floating coil type heat exchanger is heated and vaporized, so that it flows into the microchannel vaporizer. The gaseous propane in the gas reaches 0 °C and is sent to the microchannel vaporizer for standby;

S3 LNG vaporization: open the LNG outlet valve, the low-temperature and low-pressure LNG liquid in the LNG storage tank is pressurized to 13MPa by the plunger type booster pump, and then stabilized by the pressure-stabilizing tank. After the pressure is stabilized, the liquid LNG flows into In the microchannel vaporizer, the temperature of liquid LNG entering the microchannel vaporizer is -157°C, and the liquid LNG exchanges heat with gaseous propane at 0°C, so that after the liquid LNG is heated and vaporized, it flows out from the microchannel vaporizer, and the outflowing gaseous The temperature of the LNG is -10 °C, the temperature of the propane after heat exchange is reduced to -5 °C, and then the cooled propane is sent to the propane liquid storage tank for recycling;

S4 Flow control: In the process of LNG vaporization, the amount of propane exchanged with liquid LNG is controlled by adjusting the opening of the three-way valve II to match the requirements of different vaporization amounts of LNG, and 0 and 1 are used to represent the three-way valve II. When the opening of the three-way valve II is 0, it means that the pipeline connecting the three-way valve II and the micro-channel vaporizer is in a closed state, and the pipeline connected to the propane liquid storage tank is in a fully open state. When the opening degree of II is 1, it means that the pipeline connecting the three-way valve II and the micro-channel vaporizer is in a fully open state, and the pipeline connected to the propane liquid storage tank is in a closed state. When the opening degree of the three-way valve II is 0, the LNG The vaporization rate of LNG is 0kg/s. When the opening of the three-way valve II is 1, the vaporization rate of LNG is 0.3kg/s.

When the amount of LNG vaporization is small, adjust the three-way valve II to reduce the flow of propane flowing into the floating coil heat exchanger and increase the flow of propane flowing into the propane accumulator; when the amount of vaporization of LNG is large, the adjustment method is opposite , so that the flow of propane flowing into the floating coil heat exchanger is increased, and the flow of propane flowing into the propane accumulator is reduced, so as to meet the needs of different LNG vaporization volumes;

S5 LNG reheating: The vaporized LNG is sent to the air-temperature reheater for reheating to 5°C, and the heated gaseous LNG is sent to the liquid storage tank to complete the re-vaporization of LNG.

Further, in the S5, in the process of feeding the gaseous LNG into the air-temperature reheater, the pressure is adjusted by using the built-in spring that comes with the back pressure valve. When the pressure in the pipeline is smaller than the set pressure, the diaphragm of the back pressure valve blocks the pipeline under the action of the spring force, forming a pressure hold, so that the inlet pressure of the air temperature reheater reaches the set pressure; When the pressure is greater than the set pressure, the diaphragm compresses the spring and the pipeline is connected to stabilize the outlet pressure of the microchannel vaporizer.

Further, in the S5, when the vaporized amount of the gaseous LNG is large, the gaseous LNG in the air-temperature reheater directly enters the evacuation system through the evacuation pipe for evacuation.

The advantages of the present invention are: in the present invention, by adding a propane circulation unit, the direct heat exchange between propane and LNG fluid is avoided, and at the same time, a large amount of latent heat is released by using the phase change heat of propane, which effectively reduces the junction in the heat exchange process of the microchannel vaporizer. The occurrence of ice phenomenon ensures the efficient operation of the microchannel vaporizer.

In view of the fact that the propane circulation system is easy to adjust the flow of propane, it is convenient to quickly match according to the actual vaporization requirements of LNG to achieve the best heat exchange effect under the required working conditions.

By using the micro-channel vaporizer manufactured based on 3D printing technology, compared with the traditional vaporizer, the re-vaporization efficiency is greatly improved, while the volume size of the vaporizer is effectively reduced, and the overall footprint of the re-vaporization system is greatly reduced. In order to meet the re-vaporization needs of limited space, in addition, the micro-channel vaporizer manufactured based on 3D printing technology is easy to system modular assembly.

By controlling the opening of the reversing port of the three-way valve in the electric heater and propane circulation system, it can quickly adjust and match the demand of the vaporization amount.

Since all the equipments in this system are connected by welding or flanges and are connected by stainless steel pipes, it can meet the requirements of high pressure inside the system, and can be installed flexibly according to the site conditions.

Because the floating coil type heat exchanger is used in the propane circulation system, the hot water is exchanged with the propane in the pipe outside the coil, which effectively reduces the formation of scale in the pipe, improves the heat exchange efficiency and facilitates the maintenance of the system in the later stage. .

Since the present invention solves the technical problem of the LNG re-vaporization system, the present invention has practical engineering significance and can be referenced by relevant engineering personnel.

Description of drawings

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of the LNG regasification experimental system of the present invention.

Figure 2 is a front view of the microchannel vaporizer in the present invention.

Figure 3 is a side view of the microchannel vaporizer of the present invention.

Detailed ways

The following embodiments can make those skilled in the art understand the present invention more comprehensively, but do not limit the present invention to the scope of the described embodiments.

An LNG regasification experimental system as shown in Figures 1-3, including

An LNG circulation unit, the LNG circulation unit includes an LNG liquid tank 1, a liquid outlet valve 2, a plunger booster pump 3, a pressure stabilization tank 4, a microchannel vaporizer 5, a back pressure valve 6, an air temperature reheater 14, Evacuation pipe 16, three-way valve I15, pressure reducing valve 17, liquid storage tank 18, among which, LNG liquid tank 1, liquid outlet valve 2, plunger booster pump 3, pressure stabilization tank 4, microchannel vaporizer 5, The back pressure valve 6 , the air temperature reheater 14 , the three-way valve I15 , the pressure reducing valve 17 , and the liquid storage tank 18 are sequentially connected by pipelines.

The height of the LNG storage tank 1 is higher than that of the plunger type booster pump 3 . The LNG storage tank 1 is placed at a high position to ensure that the LNG entering the plunger booster pump 3 is always in a liquid state without bubbles, so that the LNG is pressurized to the required pressure.

Microchannel vaporizer 5 is a compact and efficient microchannel vaporizer manufactured based on 3D printing technology. By using the micro-channel vaporizer 5 manufactured based on 3D printing technology, compared with the traditional vaporizer, the re-vaporization efficiency is greatly improved, while the volume size of the vaporizer is effectively reduced, and the overall footprint of the re-vaporization system is greatly reduced. , to meet the re-vaporization needs of limited space, in addition, the micro-channel vaporizer manufactured based on 3D printing technology is easy to system modular assembly.

As can be seen from the schematic diagrams shown in FIGS. 2 and 3 , the microchannel vaporizer 5 includes a vaporizer core 51 . The vaporizer core 51 is a hollow cuboid structure. The LNG flow channel group and the LNG flow channel group are installed in the inner cavity of the vaporizer core 51 . The propane flow channel group, the LNG flow channel group and the propane flow channel group have several groups, which are distributed in the core body 51 of the vaporizer from top to bottom, and the LNG flow channel group and the propane flow channel group are arranged at intervals in the form of cross flow. , the LNG flow channel group is composed of a number of LNG flow channels 52 arranged horizontally along the width direction of the vaporizer core 51, and the LNG flow channel 52 extends along the long axis direction of the vaporizer core 51, and the propane flow channel group is composed of several along the The propane flow channels 53 are arranged horizontally along the long axis direction of the vaporizer core body, and the propane flow channels 53 extend along the width direction of the vaporizer core body 51. A LNG liquid inlet chamber 54 and an LNG liquid outlet chamber connected to the same side end of the flow channel 52 respectively have a propane inlet chamber 54 connected to the same side end of each propane flow channel 53 on both sides of the vaporizer core 51 in the width direction. A liquid cavity, a propane liquid outlet cavity, and a guide plate are also arranged in the propane liquid inlet cavity, so that the propane flows into the propane flow channel uniformly.

A propane circulation unit, the propane circulation unit includes a propane liquid storage tank 7, a propane circulation pump 8, a three-way valve II 9, a floating coil heat exchanger 10, an electric heater 11, a liquid inlet valve 12, and a relief valve 13, wherein , the propane liquid storage tank 7, the propane circulating pump 8, the three-way valve II 9, and the floating coil type heat exchanger 10 are connected by pipelines in turn, and the inlet of the propane liquid storage tank 7 is connected with the outlet of the microchannel vaporizer 5, floating The outlet of the coil type heat exchanger 10 is connected to the inlet of the microchannel vaporizer 5, and the remaining one outlet of the three-way valve II9 is connected to the pipeline connecting the propane liquid storage tank 7 and the microchannel vaporizer 5 through the pipeline. The electric heater 11 and the relief valve 13 are both installed on the floating coil type heat exchanger 10 .

The relief valve 13 is provided at the lowest point of the floating coil heat exchanger 10 . The relief valve 13 is arranged at the lowest point of the floating coil type heat exchanger 10 to prevent the accumulation of impurities in the water and affect the stable operation of the system.

The test method for LNG re-vaporization based on the above-mentioned LNG re-vaporization test system is achieved through the following steps:

S1 System construction: Connect the components that constitute the LNG circulation unit and the components that constitute the propane circulation unit through pipelines, and connect the LNG circulation unit to the propane circulation unit to form an LNG re-vaporization experimental system.

S2 propane cooling: First, inject cold water into the floating coil heat exchanger, and then use the electric heater to heat the cold water in the floating coil heat exchanger, and then, the liquid propane in the propane storage tank is circulated through the propane The pump increases the pressure to 0.36MPa, and then sends it into the floating coil heat exchanger through the three-way valve II, and conducts heat exchange and vaporization with the hot water in the floating coil heat exchanger, so that the gaseous gas flowing into the microchannel vaporizer The propane reaches 0°C and is sent to the microchannel vaporizer for use.

S3 LNG vaporization: Open the LNG outlet valve, the low-temperature and low-pressure LNG liquid in the LNG storage tank is pressurized to about 13MPa by the plunger type booster pump, and then stabilized by the pressure-stabilizing tank. After the pressure is stabilized, the liquid LNG Flowing into the microchannel vaporizer, the temperature of liquid LNG entering the microchannel vaporizer is -157°C, and the liquid LNG exchanges heat with gaseous propane at 0°C, so that the liquid LNG heats up and vaporizes, and flows out from the microchannel vaporizer. The temperature of the gaseous LNG is -10°C, the temperature of the propane after heat exchange is reduced to -5°C, and then the cooled propane is sent to the propane liquid storage tank for recycling;

S4 Flow control: In the process of LNG vaporization, the amount of propane exchanged with liquid LNG is controlled by adjusting the opening of the three-way valve II to match the requirements of different vaporization amounts of LNG, and 0 and 1 are used to represent the three-way valve II. When the opening of the three-way valve II is 0, it means that the pipeline connecting the three-way valve II and the micro-channel vaporizer is in a closed state, and the pipeline connected to the propane liquid storage tank is in a fully open state. When the opening degree of II is 1, it means that the pipeline connecting the three-way valve II and the micro-channel vaporizer is in a fully open state, and the pipeline connected to the propane liquid storage tank is in a closed state. When the opening degree of the three-way valve II is 0, the LNG The vaporization rate of LNG is 0kg/s. When the opening of the three-way valve II is 1, the vaporization rate of LNG is 0.3kg/s.

When the amount of LNG vaporization is small, adjust the three-way valve II to reduce the flow of propane flowing into the floating coil heat exchanger and increase the flow of propane flowing into the propane accumulator; when the amount of vaporization of LNG is large, the adjustment method is opposite , so that the flow of propane flowing into the floating coil heat exchanger is increased, and the flow of propane flowing into the propane accumulator is reduced, so as to meet the needs of different LNG vaporization volumes.

S5 LNG reheating: The vaporized LNG is sent to the air-temperature reheater for reheating to about 5°C, and the heated gaseous LNG is sent to the liquid storage tank to complete the re-vaporization of LNG.

In the process of feeding gaseous LNG into the air-temperature reheater, the built-in spring of the back pressure valve is used to adjust the pressure. When the pressure ratio in the pipeline between the micro-channel vaporizer and the air-temperature reheater is set When the pressure is small, the diaphragm of the back pressure valve blocks the pipeline under the action of the elastic force of the spring, forming a pressure hold, so that the inlet pressure of the air temperature reheater reaches the set pressure; when the pressure in the pipeline is greater than the set pressure , the diaphragm compresses the spring, and the pipeline is connected to stabilize the outlet pressure of the microchannel vaporizer.

When the vaporized amount of gaseous LNG is large, the gaseous LNG in the air-temperature reheater directly enters the evacuation system through the evacuation pipe for evacuation.

Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. a LNG re-vaporization experiment system, is characterized in that: comprising: An LNG circulation unit, the LNG circulation unit includes an LNG liquid tank, a liquid outlet valve, a plunger booster pump, a pressure stabilization tank, a microchannel vaporizer, a back pressure valve, an air temperature reheater, an emptying pipe, three Through valve I, pressure reducing valve, liquid storage tank, among which, LNG liquid tank, liquid outlet valve, plunger type booster pump, pressure stabilizer tank, micro-channel vaporizer, back pressure valve, air temperature reheater, three-way The valve I, the pressure reducing valve and the liquid storage tank are connected in sequence through pipelines, and the remaining outlet of the three-way valve I is connected with the emptying pipe; A propane circulation unit, the propane circulation unit includes a propane liquid storage tank, a propane circulation pump, a three-way valve II, a floating coil type heat exchanger, an electric heater, a liquid inlet valve, and a discharge valve, wherein the propane liquid storage tank The tank, the propane circulating pump, the three-way valve II, and the floating coil type heat exchanger are connected by pipelines in sequence, and the inlet of the propane liquid storage tank is connected with the outlet of the microchannel vaporizer, and the outlet of the floating coil type heat exchanger is connected to the outlet of the microchannel vaporizer. The inlet of the micro-channel vaporizer is connected, and the remaining outlet of the three-way valve II is connected to the pipeline connecting the propane liquid storage tank and the micro-channel vaporizer through a pipeline. on the heat exchanger. 2 . The LNG re-vaporization experimental system according to claim 1 , wherein the micro-channel vaporizer comprises a vaporizer core body, the vaporizer core body is a hollow cuboid structure, and an inner cavity of the vaporizer core body is installed with a LNG flow channel group and propane flow channel group, the LNG flow channel group and the propane flow channel group have several groups, which are distributed in the core of the vaporizer from top to bottom, and the LNG flow channel group and the propane flow channel group are in a staggered flow. The forms are arranged at intervals, the LNG flow channel group is composed of a number of LNG flow channels arranged horizontally along the width direction of the vaporizer core, and the LNG flow channels extend along the long axis direction of the vaporizer core. The propane flow The channel group consists of a number of propane flow channels arranged horizontally along the long axis of the vaporizer core, and the propane flow channels extend along the width direction of the vaporizer core. A LNG liquid inlet cavity and an LNG liquid outlet cavity connected to the same side end of the LNG flow channel, and a propane liquid inlet cavity, a propane liquid inlet cavity, a propane liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, a propane liquid liquid inlet cavity, A propane liquid outlet chamber is also provided with a guide plate in the propane liquid inlet chamber. 3. The LNG re-vaporization experimental system according to claim 1 or 2, wherein the micro-channel vaporizer is a compact and efficient micro-channel vaporizer manufactured based on 3D printing technology. 4 . The LNG re-vaporization experiment system according to claim 1 , wherein the height of the LNG liquid storage tank is higher than that of the plunger type booster pump. 5 . 5 . The LNG re-vaporization experimental system according to claim 1 , wherein the relief valve is arranged at the lowest point of the floating coil type heat exchanger. 6 . 6. A test method based on the LNG re-vaporization test system according to claim 1, characterized in that: comprising the following steps S1 system construction: connect the components that constitute the LNG circulation unit and the components that constitute the propane circulation unit through pipelines, and connect the LNG circulation unit and the propane circulation unit together to form an LNG re-vaporization experimental system; S2 propane cooling: First, inject cold water into the floating coil heat exchanger, and then use the electric heater to heat the cold water in the floating coil heat exchanger, and then, the liquid propane in the propane storage tank is circulated through the propane The pump increases the pressure until the pressure reaches 0.36MPa, and then sends it into the floating coil type heat exchanger through the three-way valve II, and conducts heat exchange and vaporization with the hot water in the floating coil type heat exchanger, so that it flows into the microchannel vaporizer. The gaseous propane in the gas reaches 0 °C and is sent to the microchannel vaporizer for standby; S3 LNG vaporization: open the LNG outlet valve, the low-temperature and low-pressure LNG liquid in the LNG storage tank is pressurized to 13MPa by the plunger type booster pump, and then stabilized by the pressure-stabilizing tank. After the pressure is stabilized, the liquid LNG flows into In the microchannel vaporizer, the temperature of liquid LNG entering the microchannel vaporizer is -157°C, and the liquid LNG exchanges heat with gaseous propane at 0°C, so that after the liquid LNG is heated and vaporized, it flows out from the microchannel vaporizer, and the outflowing gaseous The temperature of the LNG is -10 °C, the temperature of the propane after heat exchange is reduced to -5 °C, and then the cooled propane is sent to the propane liquid storage tank for recycling; S4 Flow control: In the process of LNG vaporization, the amount of propane exchanged with liquid LNG is controlled by adjusting the opening of the three-way valve II to match the requirements of different vaporization amounts of LNG, and 0 and 1 are used to represent the three-way valve II. When the opening of the three-way valve II is 0, it means that the pipeline connecting the three-way valve II and the micro-channel vaporizer is in a closed state, and the pipeline connected to the propane liquid storage tank is in a fully open state. When the opening degree of II is 1, it means that the pipeline connecting the three-way valve II and the micro-channel vaporizer is in a fully open state, and the pipeline connected to the propane liquid storage tank is in a closed state. When the opening degree of the three-way valve II is 0, the LNG The vaporization rate of LNG is 0kg/s. When the opening of the three-way valve II is 1, the vaporization rate of LNG is 0.3kg/s. When the amount of LNG vaporization is small, adjust the three-way valve II to reduce the flow of propane flowing into the floating coil heat exchanger and increase the flow of propane flowing into the propane accumulator; when the amount of vaporization of LNG is large, the adjustment method is opposite , so that the flow of propane flowing into the floating coil heat exchanger is increased, and the flow of propane flowing into the propane accumulator is reduced, so as to meet the needs of different LNG vaporization volumes; S5 LNG reheating: The vaporized LNG is sent to the air-temperature reheater for reheating to 5°C, and the heated gaseous LNG is sent to the liquid storage tank to complete the re-vaporization of LNG. 7. The test method of LNG re-vaporization according to claim 6, characterized in that: in the described S5, in the process of feeding the gaseous LNG into the air-temperature reheater, the built-in spring that comes with the back pressure valve is used to Carry out pressure adjustment. When the pressure in the pipeline between the microchannel vaporizer and the air temperature reheater is smaller than the set pressure, the diaphragm of the back pressure valve will block the pipeline under the action of the spring force, forming a hold-up pressure, so that the The inlet pressure of the air-temperature reheater reaches the set pressure; when the pressure in the pipeline is greater than the set pressure, the diaphragm compresses the spring and the pipeline is connected to stabilize the outlet pressure of the microchannel vaporizer. 8 . The test method for LNG re-vaporization according to claim 6 , wherein in the step S5 , when the vaporized amount of the gaseous LNG is large, the gaseous LNG in the air-temperature reheater directly passes through the exhaust pipe. 9 . Enter the emptying system for emptying.

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