CN216361274U

CN216361274U - BOG heating utilization and LNG regasification system

Info

Publication number: CN216361274U
Application number: CN202122697698.5U
Authority: CN
Inventors: 谷家扬; 黄华杰; 渠基顺; 陈智同; 刘富斌; 刘建春; 焦晨; 孙大巍; 王洪福
Original assignee: Changjiang Samsung Energy Technology Co ltd; Jiangsu University of Science and Technology; Marine Equipment and Technology Institute Jiangsu University of Science and Technology; Shanghai Wison Offshore and Marine Co Ltd
Current assignee: Changjiang Samsung Energy Technology Co ltd; Jiangsu University of Science and Technology; Marine Equipment and Technology Institute Jiangsu University of Science and Technology; Shanghai Wison Offshore and Marine Co Ltd
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-04-22
Anticipated expiration: 2031-11-05

Abstract

The utility model discloses a BOG heating utilization and LNG regasification system which comprises an LNG storage tank, a heat exchange working medium circulation subsystem and a cold energy recovery subsystem, wherein the heat exchange working medium circulation subsystem comprises a heat exchange working medium, a first heat exchanger and a second heat exchanger, the heat exchange working medium exchanges heat sequentially through the first heat exchanger and the second heat exchanger, the cold energy recovery subsystem comprises a third heat exchanger and air, the heat exchange working medium exchanges heat with the air through the third heat exchanger after passing through the second heat exchanger to obtain low-temperature air, the LNG storage tank is provided with a BOG outlet connected with the first heat exchanger, and an LNG extraction immersed pump connected with the second heat exchanger is arranged inside the LNG storage tank. The heat exchange transition is carried out by increasing the heat exchange working medium, the heat exchange working medium generates phase change in the heat exchanger, and absorbs or releases a large amount of latent heat, so that the exchange of air heat energy, LNG and BOG cold energy is realized, the BOG heating, LNG regasification and cold energy recovery are completed simultaneously, the energy waste is avoided, the system is simple and efficient, and the economic benefit is high.

Description

BOG heating utilization and LNG regasification system

Technical Field

The utility model relates to natural gas production, in particular to a BOG heating utilization and LNG regasification system.

Background

With the rapid increase of Natural Gas (NG) demand and the development of Liquefied Natural Gas (LNG) industry chain, Floating Storage and Regasification Unit (FSRU) is increasingly widely used, and a complete industrial system from production, Storage and transportation, shipping to receiving, regasification, cold energy utilization, peak regulation, etc. has been gradually formed. During the storage and transportation of LNG, the FSRU will slosh under the action of wind and wave flow, and the LNG storage tank or the insulated cabin inevitably exchanges heat with the outside, so that LNG is continuously vaporized to generate a large amount of flash steam (BOG). The continuous production of BOG can lead to the increase of the internal pressure of the storage tank, and if the internal pressure is not effectively treated, the continuous rise of the internal pressure can lead to serious potential safety hazards.

At present, the BOG gas problem in the market is solved by adopting a scheme that firstly, the BOG gas is combusted and directly exhausted, and the scheme not only pollutes the environment but also wastes energy; secondly, a storage tank is additionally arranged to store BOG gas for BOG gas utilization, but the BOG storage density is low, the economic value of unit volume is low, and the storage tank occupies a large space, so that the scheme is high in cost and complicated to operate; thirdly, BOG is liquefied by adopting a refrigeration technology, but due to the technical limitation, BOG gas is liquefied and recovered again by pressurizing and cooling, so that huge energy consumption is caused and the process flow is complex.

BOG gas is collected, BOG is heated by adopting a heat exchange technology, and cold energy released by the BOG is recovered, so that the BOG gas is directly utilized, the trend of energy conservation and environmental protection at present is better met, and the process flow is simple. Meanwhile, before being delivered to the NG user side, LNG needs to be re-vaporized, and in the process, LNG needs to absorb a large amount of heat and release cold energy. In the prior art, different heat sources are adopted to respectively act on two processes of BOG heating utilization and LNG regasification, so that the whole heat exchange system is complicated and high in cost. In addition, in the heat exchange process, the heat source directly exchanges heat with the BOG and the LNG, so that the phenomenon of icing or incomplete vaporization of a heat exchange medium is easily caused.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: in order to overcome the defects, the utility model provides a BOG heating utilization and LNG regasification system which shares one heat source and exchanges heat with the heat source through a heat exchange working medium.

The technical scheme is as follows: in order to solve the problems, the BOG heating utilization and LNG regasification system comprises an LNG storage tank, a heat exchange working medium circulation subsystem and a cold energy recovery subsystem, wherein the heat exchange working medium circulation subsystem comprises a heat exchange working medium, a first heat exchanger and a second heat exchanger, the heat exchange working medium sequentially exchanges heat through the first heat exchanger and the second heat exchanger, the cold energy recovery subsystem comprises a third heat exchanger and air, the heat exchange working medium passes through the second heat exchanger and then passes through the third heat exchanger, the heat exchange working medium exchanges heat with the air passing through the third heat exchanger, low-temperature air is formed after the heat exchange of the third heat exchanger, the LNG storage tank is provided with a BOG outlet, an immersed pump for extracting LNG is arranged in the LNG storage tank, the BOG outlet is connected with the first heat exchanger, and the output end of the immersed pump is connected with the second heat exchanger.

Furthermore, the heat exchange working medium circulation subsystem further comprises a heat exchange working medium buffer tank arranged between the second heat exchanger and the third heat exchanger and a gas-liquid separator arranged between the first heat exchanger and the second heat exchanger, wherein a gas outlet of the gas-liquid separator is communicated with an inlet of the second heat exchanger, and a liquid outlet of the gas-liquid separator is communicated with an inlet of the heat exchange working medium buffer tank.

Furthermore, the heat exchange working medium circulation subsystem further comprises a first three-way valve arranged between the first heat exchanger and the gas-liquid separator, and the three ends of the first three-way valve are respectively connected with the first heat exchanger, the gas-liquid separator and the heat exchange working medium buffer tank.

Furthermore, the output end of the heat exchange working medium buffer tank is provided with a circulating pump, and the heat exchange working medium is propane working medium.

Furthermore, the cold energy recovery subsystem further comprises an air pressure regulating valve arranged at the outlet of the third heat exchanger.

Further, the cold energy recovery subsystem further comprises an air purifier and an air compressor, wherein the output end of the air compressor is communicated with the input end of the air purifier, and the output end of the air purifier is communicated with the inlet end of the third heat exchanger.

Furthermore, the first heat exchanger and the second heat exchanger adopt microchannel heat exchangers, and the third heat exchanger adopts a fin type heat exchanger.

Further, the first heat exchanger and the second heat exchanger are both of a 3D printing structure.

Further, a BOG gas compressor is arranged between the BOG outlet and the first heat exchanger.

Has the advantages that: compared with the prior art, the utility model has the obvious advantages that the heat exchange transition is carried out by adding the heat exchange working medium (propane) circulation subsystem, the heat exchange working medium generates phase change in each heat exchanger, a large amount of latent heat is absorbed or released, the exchange of air heat energy and LNG or BOG cold energy is realized, the energy waste is avoided, three process flows of BOG heating utilization, LNG regasification, low-temperature air preparation and the like are completed, and the system is simple, convenient to operate, high in heat exchange efficiency and high in economic benefit. The direct heat exchange of the air with the LNG and the BOG is avoided, the direct heat exchange of the air is single-phase heat exchange, the heat transfer efficiency is low, and water vapor in the air is easy to freeze to block the heat exchanger. A large amount of heat is absorbed from the air by utilizing the phase change of liquid propane into gaseous propane, and then the heat in the gaseous propane is transferred to the low-temperature BOG gas through the first heat exchanger, so that the BOG heating is completed. In the BOG heating process, the BOG does not have phase change, the absorbed heat is relatively less, so when BOG heating utilization and LNG regasification are carried out simultaneously, propane does not change the phase when exchanging heat with the BOG, a large amount of latent heat is reserved, gaseous propane passes through the second heat exchanger and transfers the heat to LNG, propane liquefaction is carried out, and LNG regasification is completed.

Drawings

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

Detailed Description

As shown in fig. 1, the BOG heating utilization and LNG regasification system in this embodiment includes a BOG heating utilization subsystem, an LNG regasification subsystem, a heat exchange medium circulation subsystem, and a cold energy recovery subsystem. The cold energy recovery subsystem can be used as an indirect heat source to simultaneously heat the BOG and the LNG, the cold energy of the BOG and the LNG can be recycled, and the cold energy recovery subsystem is used as a heat exchange medium to heat the BOG and the LNG through the heat exchange working medium circulation subsystem. The heat exchange working medium circulation subsystem and the cold energy recovery subsystem exchange heat through a third heat exchanger 14 (a fin type heat exchanger); the BOG heating utilization subsystem and the LNG regasification subsystem exchange heat with the heat exchange working medium circulation subsystem respectively through the first heat exchanger 4 (micro-channel heat exchanger) and the second heat exchanger 9 (micro-channel heat exchanger).

The system is suitable for FSRU or FLNG, integrates three process flows of LNG regasification, BOG heating utilization, cold energy recovery and the like, guarantees the simplicity and high efficiency of the system, can effectively avoid the limited space limitation of FSRU or FLNG, improves the space utilization rate, and creates higher economic benefit.

A control method of a BOG heating utilization and LNG regasification system can be divided into two working modes according to working condition requirements: firstly, BOG heating utilization and LNG regasification are carried out simultaneously, LNG needs to be vaporized before being conveyed to an NG user side, BOG is generated continuously in the process, a large amount of BOG usually remains in an LNG storage tank and cannot be exhausted, the system meets the requirements of BOG heating utilization and LNG regasification at the same time, resource waste is avoided, and economic benefit is maximized; and secondly, BOG is independently heated and utilized, LNG does not need to be re-vaporized under the conditions of LNG storage and transportation, a large amount of LNG stored and transported can be continuously vaporized to generate a large amount of BOG gas, the system meets the requirement of independent BOG heating and utilization, the BOG is timely treated, the resource waste is avoided, and the potential safety hazard is reduced.

The heat exchange working medium circulation subsystem comprises a heat exchange working medium buffer tank 12, a circulating pump 13, a third heat exchanger 14, a first heat exchanger 4, a first three-way valve 16, a gas-liquid separator 17, a second heat exchanger 9 and a propane pressure regulating valve 15 which are sequentially connected through pipelines. The liquid propane is colorless and slightly toxic, has stable and safe chemical properties, belongs to hydrocarbon, and compared with the traditional heat exchange working media such as Freon and the like, the liquid propane does not damage the atmospheric ozone layer, does not cause greenhouse effect, and is green and environment-friendly. Propane is easy to obtain, the cost is low, and the propane gradually replaces the traditional heat exchange working medium and becomes the most mainstream heat exchange working medium. Liquid propane exchanges heat with air through the third heat exchanger 14, and liquid propane vaporization produces the phase transition and stores a large amount of latent heat, later exchanges heat with BOG and LNG successively through the pipeline, and propane liquefaction releases a large amount of latent heat, and heat exchange efficiency is high, can satisfy BOG heating utilization and LNG demand of regasification.

The pressure of propane in the heat exchange working medium buffer tank 12 is 0.1-0.3 MPa, and the temperature is-45 ℃ to-15 ℃. Adjusting the frequency of the circulating pump 13, increasing the pressure of the propane, and controlling the volume flow of the liquid-phase propane to be 3.5-4.5 m³H is used as the reference value. The pressurized liquid propane enters the finned heat exchanger 12 to exchange heat with air, and the propane absorbs heat to vaporize, so that the temperature is increased. The gasified propane enters the micro-channel heat exchanger 4 through the propane pressure regulating valve 15 to exchange heat with BOG, the opening degree of the propane pressure regulating valve 15 is regulated, and the operating pressure of the propane is controlled to be 0.4-0.8 MPa. And respectively reading the pressure and the temperature of the propane before and after heat exchange with the BOG by a pressure transmitter and a temperature transmitter before and after the micro-channel heat exchanger 4. Before heat exchange with BOG, the pressure value of propane is 0.4-0.8 MPa, and the temperature value is-5-20 ℃; after heat exchange with BOG, the pressure value of propane is 0.2-0.6 MPa, and the temperature value is-30-10 ℃. And calculating the saturation temperature of the propane before and after the heat exchange with the BOG under the current pressure so as to calculate the superheat degree or the supercooling degree of the propane before and after the heat exchange with the BOG. When BOG is independently heated and utilized, the superheat degree of propane before heat exchange with BOG is controlled to be 3-5 ℃, and the propane is ensured to be in a complete gas phase state before entering the micro-channel heat exchanger 4; the supercooling degree of propane after heat exchange with BOG is controlled to be 3-5 ℃, the phase change process from gas phase to liquid phase of the propane is mainly carried out in the micro-channel heat exchanger 4, huge latent heat in the phase change process is fully utilized, and the efficiency of the heat exchanger is improved. When BOG heating utilization and LNG regasification are carried out simultaneously, the propane superheat degree before heat exchange with BOG is controlled to be 5-10 ℃, the propane superheat degree after heat exchange with BOG is controlled to be 3-5 ℃, it is guaranteed that gas-phase propane does not undergo phase change in the micro-channel heat exchanger 4, sufficient heat is still contained after heat exchange with BOG, and the subsequent LNG regasification is carried out. Propane after heat exchange with the BOG is divided into two flow directions by the first three-way valve 16, one of which is to separately heat the BOGWhen in use, liquid propane flows to the heat exchange working medium buffer tank 12 through the first three-way valve 16 to carry out the next circulation; and secondly, when BOG heating utilization and LNG revaporization are carried out simultaneously, propane flows into a gas-liquid separator 17 through a first three-way valve 16, delay and errors are inevitably generated in measurement, calculation and control when the propane exchanges heat with the BOG, so that a small amount of liquid-phase propane is generated, the liquid-phase propane returns to a heat exchange working medium buffer tank 12 again through a liquid phase port of the gas-liquid separator 17, most of the gas-phase propane flows into a microchannel heat exchanger 9 through a gas phase port to exchange heat with the LNG, the LNG revaporizes and liquefies the propane, and the pressure and the temperature of the gas-phase propane are respectively read through a pressure transmitter and a temperature transmitter behind the microchannel heat exchanger 9, wherein the pressure value is 0.1-0.3 MPa, and the temperature value is-45-15 ℃. And calculating the saturation temperature of the propane behind the micro-channel heat exchanger 9 under the current pressure, thereby calculating and controlling the supercooling degree of the propane behind the micro-channel heat exchanger 9 to be 3-5 ℃, ensuring that the phase change process from the gas phase to the liquid phase of the propane is mainly carried out in the micro-channel heat exchanger 9, fully utilizing the huge latent heat in the phase change process and improving the efficiency of the heat exchanger. The propane after heat exchange by the micro-channel heat exchanger 9 returns to the heat exchange working medium buffer tank 12 for next circulation.

The third heat exchanger 14 adopts a fin type heat exchanger, the heat exchange performance is good and stable, liquid propane circulates in the pipe, and the cold energy of the propane is transmitted to air flowing between the fins through the fins tightly wound on the steel pipe, so that the effects of cooling the air and heating the propane are achieved. In order to prevent the condensation of residual moisture in the air which may occur in the heat exchanger and cause the reduction of the heat exchange rate, the fin type heat exchanger is arranged for standby. In this embodiment, microchannel heat exchanger 4 and microchannel heat exchanger 8 are the microchannel heat exchanger based on 3D print architecture, this kind of heat exchanger compares with traditional heat exchanger, when improving heat exchange efficiency greatly, the volume size of heat exchanger has effectively been reduced, entire system's occupation space has been reduced to a great extent, in order to satisfy the demand of arranging the system in FSRU finite space, it has the steel construction bearing pressure big, also can satisfy the operational requirement of system high pressure, furthermore, the microchannel heat exchanger who adopts 3D print architecture easily the system modularization equipment.

The heat exchange working medium circulation subsystem has high controllability, LNG regasification is carried out according to the requirement, the flow direction of propane is controlled by adjusting the first three-way valve 16, two working modes can be realized, and one mode is that BOG heating utilization and LNG regasification are carried out simultaneously; and the other is that BOG is heated and utilized independently. According to the working condition requirement, the system is simply, conveniently and flexibly adjusted, the heat of the gaseous propane is fully utilized, and the high heat exchange efficiency is kept. The rate of propane circulation, i.e. the rate at which propane transfers heat from the air to the LNG, is controlled to match the required requirements of BOG heating utilization and LNG regasification by adjusting the circulation pump 13 to increase the pressure and mass flow of propane.

The cold energy recovery subsystem comprises an air inlet valve 18, an air compressor 19, an air purifier 20, a finned heat exchanger 14 and an air pressure regulating valve 21 which are sequentially connected through pipelines. After the air inlet valve 18 is opened, air enters the air compressor 19 to be compressed, the temperature of the air entering the air inlet valve 18 is 5-30 ℃, the frequency of the air compressor 19 is adjusted, and the volume flow of the air is controlled to be 1000-1200 m³And h, increasing the air pressure, adjusting the opening of the air pressure adjusting valve 21, and controlling the operating pressure of the air to be 0.5-1.5 MPa. The compressed air enters an air purifier 20, the purified (dust-removed and dried) air enters a finned heat exchanger 14 to exchange heat with liquid propane, and the air temperature is reduced to obtain low-temperature air, wherein the air temperature is-20-0 ℃. The low-temperature air is delivered to the cold energy utilization end through the air pressure regulating valve 21. When the BOG heating amount and the LNG revaporization amount are small, the air inlet valve 18 is adjusted to reduce the air suction amount, the frequency of the air compressor 19 is adjusted to reduce the air volume flow, and the air compressor 19 and the air pressure adjusting valve 21 are adjusted to reduce the air pressure; when the BOG heating amount and the LNG vaporization amount are large, the adjustment method is opposite. The mass flow of the air is controlled by adjusting the frequency of the air compressor 19, the air pressure is controlled by adjusting the opening of the air pressure adjusting valve 21, and the controllability is high, so that the operation parameters of the air can be adjusted to quickly match the requirements of BOG heating utilization and LNG regasification, and the optimal heat exchange effect under the required working condition is achieved.

The air purifier 20 comprises an air dust collector and an air dryer, outside air enters the subsystem through the air inlet valve 18, is pressurized by the air compressor 19 and then enters the air purifier 20 to remove moisture and various microparticle impurities in the air, and the purified air enters the finned heat exchanger 14 to exchange heat with propane. The cold energy that two in-process releases of retrieving BOG heating utilization and LNG regasification in the cold energy recovery subsystem will collect the cold energy and store in the low temperature air, and the low temperature air of production is carried to the cold energy along the pipeline and is utilized the end, and the low temperature air can directly produce economic value, and the low temperature air can be used to FSRU's cold energy user side, for example oil cooler, the pump cabin ventilation of turbine, warehouse are cold-stored and flue gas cooling etc. realize the comprehensive utilization of energy.

The BOG heating utilization subsystem comprises an LNG storage tank 1, a BOG air inlet valve 2, a BOG gas compressor 3, a micro-channel heat exchanger 4 and a second three-way valve 6 which are sequentially connected through pipelines. The pressure of BOG gas in the LNG storage tank 1 is 0.1-0.3 MPa, and the temperature is-162 ℃ to-120 ℃. After the BOG air inlet valve 2 is opened, the BOG generated in the LNG storage tank 1 enters a pipeline and then enters the BOG gas compressor 3, the frequency of the BOG gas compressor 3 is adjusted, the BOG pressure is increased, and the BOG volume flow is controlled to be 600-1000 m³And h, adjusting the opening of the BOG pressure adjusting valve 5 to control the operation pressure of the BOG to be 0.5-1.5 MPa. After being pressurized by a BOG gas compressor 3, the BOG enters a micro-channel heat exchanger 4 to exchange heat with gaseous propane, BOG heating is completed, the heated BOG is divided into two flow directions through a second three-way valve 6, and one of the two flow directions is that when the BOG is independently heated and utilized, the BOG is conveyed to a fuel gas user side, such as a ship host, a ship generator and the like, through the second three-way valve 6; and secondly, when BOG heating utilization and LNG regasification are carried out simultaneously, BOG is converged into NG generated by LNG regasification through the second three-way valve 6 and is sent to an NG user side along a conveying pipeline. When BOG is independently used by heating, the temperature of the BOG is increased to 0-10 ℃; when BOG heating utilization and LNG regasification are carried out simultaneously, BOG is heated to-30 ℃ to-10 ℃. The pipeline of collecting BOG is connected with LNG storage tank 1, guarantees that the pipeline entry is located the LNG liquid level above, avoids LNG to get into BOG gas compressor 3 and causes its damage, extension compressor life.

The LNG regasification subsystem comprises an LNG storage tank 1, an immersed pump 7, an LNG liquid inlet valve 8, a micro-channel heat exchanger 9 and a regulating valve 10 which are sequentially connected through pipelines. In this embodiment, the immersed pump 7 is a low-temperature immersed pump, and is placed at the bottom in the LNG storage tank, and after the LNG liquid inlet valve 8 is opened, the frequency of the immersed pump 7 is adjusted, so that the volume flow of LNG is controlled to be 3-3.5 m3/h, the LNG pressure is increased, the opening degree of the LNG pressure regulating valve 10 is adjusted, and the operating pressure of LNG is controlled to be 7-13 MPa. The immersed pump 7 conveys LNG in the LNG storage tank 1 to the micro-channel heat exchanger 9, the LNG exchanges heat with separated gaseous propane, the LNG is vaporized into NG again, the pressure of the NG is read by a pressure transmitter and a temperature transmitter after passing through the micro-channel heat exchanger 9, the pressure value of the NG is 6-12 MPa, and the temperature value is-30 ℃ to-10 ℃. And the high-pressure NG is depressurized to 0.1-0.7 MPa through a depressurization pore plate 11 and is sent to an NG user side along a conveying pipeline. The immersed pump 7 is placed at the lowest position in the LNG storage tank 1 to ensure that the immersed pump 76 is always under the liquid level for LNG pressurization and powering of the LNG regasification subsystem.

During the LNG storage and transportation process, LNG does not need to be re-vaporized, but a large amount of stored and transported LNG can be continuously vaporized to generate a large amount of BOG gas, and if the stored and transported LNG is not processed in time, the potential safety hazard is greatly increased. This system accessible first three-way valve 16 realizes carrying out BOG heating alone and utilizes, in time handles a large amount of BOG, reduces the potential safety hazard, and make full use of resource avoids extravagant. All equipment of the system is connected by stainless steel pipes in a welding or flange connection mode, so that the requirement of high pressure in the system can be met, and meanwhile, the system can be flexibly installed according to the field condition. The system solves the technical problems of BOG heating utilization and LNG regasification systems, has practical engineering significance, and can be used for reference of related engineering personnel. In the examples and the drawings in the specification, only the core equipment and devices in the BOG heating utilization and LNG regasification system are mainly illustrated, and in addition, a large number of auxiliary devices and instruments, such as liquid level, flow, pressure and temperature transmitters, auxiliary valves, PLC control systems and the like, are not particularly illustrated in the patent and the drawings.

Claims

1. A BOG heating utilization and LNG regasification system comprises an LNG storage tank (1) and is characterized by further comprising a heat exchange working medium circulation subsystem and a cold energy recovery subsystem, wherein the heat exchange working medium circulation subsystem comprises a heat exchange working medium, a first heat exchanger (4) and a second heat exchanger (9), the heat exchange working medium sequentially passes through the first heat exchanger (4) and the second heat exchanger (9) for heat exchange, the cold energy recovery subsystem comprises a third heat exchanger (14) and air, the heat exchange working medium passes through the second heat exchanger (9) and then passes through the third heat exchanger (14), the heat exchange working medium exchanges heat with the air passing through the third heat exchanger (14) and forms low-temperature air after heat exchange through the third heat exchanger (14), the LNG storage tank (1) is provided with a BOG outlet, an LNG immersed pump (7) for extracting LNG is arranged inside the LNG storage tank (1), and the BOG outlet is connected with the first heat exchanger (4), the output end of the immersed pump (7) is connected with the second heat exchanger (9).

2. The BOG heating utilization and LNG regasification system of claim 1, wherein the heat exchange medium circulation subsystem further comprises a heat exchange medium buffer tank (12) disposed between the second heat exchanger (9) and the third heat exchanger (14), and a gas-liquid separator (17) disposed between the first heat exchanger (4) and the second heat exchanger (9), a gas outlet of the gas-liquid separator (17) is communicated with an inlet of the second heat exchanger (9), and a liquid outlet of the gas-liquid separator (17) is communicated with an inlet of the heat exchange medium buffer tank (12).

3. The BOG heating utilization and LNG regasification system of claim 2 wherein the heat exchange working medium circulation subsystem further comprises a first three-way valve (16) disposed between the first heat exchanger (4) and the gas-liquid separator (17), and three ends of the first three-way valve (16) are respectively connected to the first heat exchanger (4), the gas-liquid separator (17), and the heat exchange working medium buffer tank (12).

4. The BOG heating utilization and LNG regasification system of claim 3 wherein the output end of the heat exchange working medium buffer tank (12) is provided with a circulation pump (13), and the heat exchange working medium is propane working medium.

5. The BOG heating utilization and LNG regasification system according to claim 1, wherein the cold energy recovery subsystem further comprises an air pressure regulating valve (21) provided at an outlet of the third heat exchanger (14).

6. The BOG heating utilization and LNG regasification system according to claim 5, wherein the cold energy recovery subsystem further comprises an air purifier (20), an air compressor (19), an output of the air compressor (19) being in communication with an input of the air purifier (20), an output of the air purifier (20) being in communication with an input of the third heat exchanger (14).

7. The BOG heating utilization and LNG regasification system according to claim 1, wherein the first heat exchanger (4) and the second heat exchanger (9) employ a micro channel heat exchanger, and the third heat exchanger (14) employs a fin heat exchanger.

8. The BOG heating utilization and LNG regasification system according to claim 7, wherein the first heat exchanger (4) and the second heat exchanger (9) are both 3D printed structures.

9. The BOG heating utilization and LNG regasification system according to claim 1, wherein a BOG gas compressor (3) is provided between the BOG outlet and the first heat exchanger (4).