An LNG frost suppression and efficiency enhancement air bath gasification system and method using solar heat pump and air circulation

Abstract

The present invention relates to an LNG frost suppression and efficiency-enhancing air-bath type gasification system utilizing a solar heat pump and air circulation. The refrigerant absorbs solar radiation and ambient heat to heat the air in the air supply pipe; the ambient air is dehumidified by the preheater and flows through the condenser to absorb the heat of the refrigerant, and then enters the wind hood to heat the LNG in the gasifier, the air is further dehumidified, and the cooled and dried air flows into the air supply pipe through the return air pipe to form an air circulation; a portion of the LNG flowing out of the storage tank enters the preheater, and by controlling the LNG flow rate, the LNG flowing out of the preheater is ensured to remain in a liquid state, and the preheated LNG is merged into the LNG flowing out of the storage tank; the wind hood equipped with tempered glass produces a greenhouse effect inside. The invention makes full use of the cold energy of LNG to reduce the moisture content of the circulating air, utilizes solar energy and air energy to heat the circulating air, and creates a microclimate suitable for the efficient operation of the air-temperature gasifier frost suppression, which is energy-saving and environmentally friendly, and has good economic and social benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar heat pump technology and air bath gasification technology, and in particular relates to a liquefied natural gas (LNG) frost suppression and efficiency enhancement air bath gasification system and method utilizing a solar heat pump and air circulation. Background Art

[0002] Natural gas can be liquefied into a colorless and odorless liquid at -162℃ and normal pressure, which is called liquefied natural gas (LNG for short). When LNG is used as fuel or industrial raw material, it must be vaporized into a normal temperature gas state by a vaporizer with a certain amount of heat before use.

[0003] Air-temperature vaporizers use air in the atmosphere to vaporize LNG. When the temperature is low, frost and ice easily accumulate on the surface of the vaporizer, which seriously affects the vaporization capacity of the vaporizer. Therefore, two groups of air-temperature vaporizers are generally used alternately. When one group is defrosting and deicing, the other group is turned on and running. This increases the initial investment and floor space. At the same time, when the ambient temperature is low, natural defrosting is slow and difficult, and a large amount of high-grade energy is required for defrosting. In addition, during the process of air-temperature vaporizers vaporizing LNG, the moisture in the air is cooled and easily forms fog around the vaporizer, which seriously affects the ecological environment and visual distance around the gasification station.

[0004] The patent "A system and method for gasifying LNG using a solar heat pump" (patent number ZL201610067782.X) describes a system for gasifying LNG using a solar heat pump, but the technology has the following problems: 1. The ambient air is only heated by the air condenser, the air only heats up but the moisture content does not change, the phase change driving force of the water vapor in the air remains basically unchanged, and frost and ice accumulation are not suppressed from the source; 2. The ambient air is heated by the air condenser under the action of the fan and then sent to the air-temperature vaporizer placed in the atmospheric environment. The hot air dissipates quickly in the infinite space and is not enough to form an orderly airflow between the fin tube bundles of the air-temperature vaporizer, reducing the heat exchange efficiency; 3. The cold fog phenomenon around the air-temperature vaporizer cannot be solved. Summary of the invention

[0005] In order to overcome the above-mentioned technical defects, the present invention provides an LNG frost suppression and efficiency enhancement air-bath gasification system and method using a solar heat pump and air circulation. The system uses a solar heat pump, an LNG air-temperature gasifier, an LNG preheater and an air circulation system to create the warm and dry air required for LNG air-bath gasification, thereby reducing the phase change driving force of frost on the surface of the air-temperature gasifier and fogging around it, and essentially solves the problem of performance deterioration of traditional LNG air-temperature gasifiers due to surface frost and ice accumulation and the phenomenon of cold fog generation, thereby improving the gasification efficiency and gasification economy of the LNG air-temperature gasifier.

[0006] The technical solution of the present invention to solve the technical problem is as follows:

[0007] An LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation, characterized in that the system comprises a direct expansion solar heat pump, an air circulation subsystem, an air temperature preheater 12, an air temperature gasifier 18, an LNG storage tank 22 and a gas supply network 26;

[0008] In the direct expansion solar heat pump, the heat collecting evaporator 1, the compressor 2, the air condenser 3 and the expansion valve 4 are sequentially connected through pipelines to form a closed refrigerant circulation path;

[0009] The heat collector evaporator 1 is a bare plate type flat plate collector, comprising a refrigerant coil and a base plate;

[0010] The LNG outlet of the LNG storage tank 22 is connected to the inlet of the LNG bypass pipe 23 and the LNG inlet of the air-temperature vaporizer 18 respectively; the outlet of the LNG bypass pipe 23 is connected to the LNG inlet of the air-temperature preheater 12; the LNG outlet of the air-temperature preheater 12 is connected to the inlet of the LNG output pipe 24; the outlet of the LNG output pipe 24 is connected to the LNG inlet of the air-temperature vaporizer 18, and the natural gas outlet of the air-temperature vaporizer 18 is connected to the gas supply network 26 through the natural gas pipe 25, and the natural gas pipe 25 is provided with a temperature measuring device 29 and a closed full-lift safety valve 30;

[0011] The air circulation subsystem includes an induced draft duct 5, an air supply duct 6, a return air duct 9, an exhaust duct 10, an air hood 8 and a fan 15; the outlet of the induced draft duct 5 is connected to the inlet of the air supply duct 6, the outlet of the air supply duct 6 is connected to the lower end of the air hood 8, the inlet of the return air duct 9 is connected to the top of the air hood 8, and the outlet of the return air duct 9 is connected to the inlet of the exhaust duct 10 and the inlet of the air supply duct 6 respectively; the outlet of the exhaust duct 10 and the inlet of the induced draft duct 5 are connected to the atmospheric environment; the fan 15 is placed at the inlet of the air supply duct 6; the air temperature vaporizer 18 is placed in the center of the air hood 8;

[0012] The air condenser 3 and the air-temperature evaporator 18 share a fan 15 .

[0013] The LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that the air condenser 3 is a surface heater placed in the air supply pipe 6, the refrigerant flows in the heater tube, and the air is pressurized by the fan 15 and forced to flow through the outer surface of the heater tube.

[0014] The LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that the air temperature preheater 12 is an aluminum fin tube heat exchanger placed in the induced draft duct 5, and LNG flows in the preheater tube.

[0015] The LNG frost suppression and efficiency enhancement air-bath gasification system utilizing a solar heat pump and air circulation is characterized in that the draft duct 5, the supply air duct 6 and the exhaust air duct 10 are respectively provided with a first electric air valve 14, a second electric air valve 16 and a third electric air valve 21; the inlet of the draft duct 5 and the outlet of the exhaust air duct 10 are respectively provided with rainproof louvers 11; an S-shaped water seal 13 is provided at the bottom of the draft duct 5, and the bottom slope is 0.1%, sloping toward the S-shaped water seal 13; an air supply port 17 is provided at the outlet of the supply air duct 6; a guide plate 19 is provided at the inlet elbow of the return air duct 9, the horizontal section of the return air duct 9 has a slope of 0.1%, sloping toward the air temperature gasifier 18, and a natural gas leak alarm 20 is provided at the high point of the horizontal section of the return air duct 9.

[0016] The LNG frost suppression and efficiency enhancement air-bath gasification system utilizing a solar heat pump and air circulation is characterized in that check valves 28 are provided on the branches connecting the LNG outlet of the LNG storage tank 22 to the LNG inlet of the air-temperature preheater 12 and the air-temperature gasifier 18, respectively, to ensure that there will be no backflow when the pressure in the pipeline is abnormal; an emergency shut-off valve 27 is provided on the LNG outlet pipeline of the LNG storage tank 22, and the distance between the emergency shut-off valve 27 and the air-temperature gasifier 18 is not less than 15 meters, and the emergency shut-off valve 27 is interlocked with a natural gas leak alarm 20 and a temperature measuring device 29, respectively.

[0017] The LNG frost suppression and efficiency enhancement air-bath gasification system using solar heat pump and air circulation is characterized in that the hood 8 is made of stainless steel plate, the top projection of the hood 8 is square, a plurality of square holes of equal area are opened on the south side and the top of the hood 8 to install single-layer tempered white glass 31, a closed inspection door 32 is provided on the north side of the hood 8, an S-shaped water seal 13 is provided at the bottom of the hood 8, the bottom slope is 0.1%, and the slope is towards the S-shaped water seal 13, and the hood 8 is fixedly supported by a bracket 7;

[0018] The enclosed inspection door 32 is a swing door that opens outwards;

[0019] The bracket 7 is made of stainless steel, the top of the bracket 7 is welded to the bottom of the wind hood 8, and the bottom of the bracket 7 is fixed to the ground by anchor bolts; there are four brackets 7, and the top projection connecting the brackets 7 is a square, forming a concentric square with the top projection of the wind hood 8.

[0020] The LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that the fan 15 is a variable frequency explosion-proof fan.

[0021] The LNG frost suppression and efficiency enhancement air-bath gasification method using a solar heat pump and air circulation is characterized in that, when the operation starts, the first electric air valve 14, the second electric air valve 16, the fan 15 and the compressor 2 are opened, and the third electric air valve 21 is closed. The ambient air enters the induced draft duct 5 under the action of the fan 15, flows through the air-temperature preheater 12 to heat the input LNG, and the condensed water condensed on the surface of the air-temperature preheater 12 during the heating process is discharged through the S-shaped water seal 13. The dehumidified and cooled air flows through the air condenser 3 to be heated, and then enters the wind hood 8 through the air supply port 17, flows through the air-temperature vaporizer 18 to heat the input LNG to vaporize it, and the condensed water condensed on the surface of the air-temperature vaporizer 18 during the gasification process is discharged through the S-shaped water seal 13. The air cooled and further dried by the air-temperature vaporizer 18 flows through the return air duct 9 into the air supply duct 6 to form an air circulation; after the air volume in the air supply duct 6 is stabilized, the first electric air valve 14 is closed;

[0022] The refrigerant releases the heat absorbed by the heat collecting evaporator 1 from the solar radiation and the ambient air to the air in the air supply pipe 6 through the air condenser 3; the solar energy enters the wind hood 8 through the single-layer tempered white glass 31 on the south side and top surface of the wind hood 8, generating a greenhouse effect and heating the air in the wind hood 8;

[0023] A portion of the LNG flowing out of the LNG storage tank 22 enters the air-temperature preheater 12 to absorb the heat of the air in the induced draft pipe 5. By controlling the flow rate of LNG entering the air-temperature preheater 12, it is ensured that the LNG flowing out of the air-temperature preheater 12 is always in liquid state; the LNG preheated by the air-temperature preheater 12 is merged into another stream of LNG flowing out of the LNG storage tank 22, and is input into the air-temperature vaporizer 18 for vaporization, and then enters the gas supply network 26 for supply to users after pressure regulation, metering, and odorization;

[0024] When the air-temperature vaporizer 18 is under maintenance, the emergency shut-off valve 27 is closed, and the first electric air valve 14 , the third electric air valve 21 and the closed maintenance door 32 are opened to ensure the air quality in the air hood 8 .

[0025] The beneficial effects of the present invention are:

[0026] 1. Taking advantage of the low temperature characteristics of LNG, the air is double dehumidified and dried through the air-temperature preheater and air-temperature vaporizer, and the air can be repeatedly deeply dehumidified by the air-temperature vaporizer through the air circulation subsystem, solving the problem of frost accumulation on the surface of the air-temperature vaporizer and the adverse effects it brings from the source;

[0027] 2. The wind hood can make the hot air form an effective airflow organization on the outer surface of the air-temperature vaporizer, improve the air-side convection heat transfer coefficient, and improve the heat exchange efficiency of the air-temperature vaporizer;

[0028] 3. The air is deeply dehumidified and dried, and the air-temperature vaporizer is placed in the wind hood, which solves the cold fog phenomenon in the gasification station;

[0029] 4. The wind hood and single-layer tempered white glass can produce a greenhouse effect inside the wind hood, making full use of solar energy and improving the heat exchange efficiency of the air-temperature vaporizer;

[0030] 5. The air condenser is placed in the air supply pipe, and the air can flow through it at a high speed and in an orderly manner. The air condenser has a good heat exchange effect, which improves the thermal performance of the solar heat pump;

[0031] 6. According to the changing demand of gasification load of air temperature gasifier, the variable frequency fan can adjust the air volume and wind speed in time to save the power consumption of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a process diagram of an LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation;

[0033] Figure 2 This is the south side view of the wind shield;

[0034] Figure 3 This is the east side view of the wind shield;

[0035] Figure 4 This is the west side view of the wind shield;

[0036] Figure 5 This is the north side view of the wind shield;

[0037] Figure 6 This is a top view of the wind shield.

[0038] Explanation of reference numerals: 1-heat collecting evaporator; 2-compressor; 3-air condenser; 4-expansion valve; 5-draft duct; 6-air supply duct; 7-bracket; 8-air hood; 9-return air duct; 10-exhaust duct; 11-rainproof shutters; 12-air temperature preheater; 13-S-type water seal; 14-first electric air valve; 15-fan; 16-second electric air valve; 17-air supply port; 18-air temperature vaporizer; 19-guide plate; 20-LNG leakage monitoring device; 21-third electric air valve; 22-LNG storage tank; 23-LNG bypass pipe; 24-LNG output pipe; 25-natural gas pipeline; 26-gas supply network; 27-emergency shut-off valve; 28-check valve; 29-temperature measuring device; 30-closed full-open safety valve; 31-single-layer tempered white glass; 32-enclosed inspection door. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0040] The following is combined with Figure 1-6 , describing an LNG frost suppression and efficiency enhancement air bath gasification system and method using a solar heat pump and air circulation:

[0041] like Figure 1 An LNG frost suppression and efficiency enhancement air-bath gasification system utilizing a solar heat pump and air circulation is shown, the system comprising a direct expansion solar heat pump, an air circulation subsystem, an air-temperature preheater 12, an air-temperature gasifier 18, an LNG storage tank 22 and an air supply network 26; the air condenser 3 is a surface heater, which is placed in the air supply pipe 6, the refrigerant flows in the heater pipe, and the air is pressurized by the fan 15 and forced to flow through the outer surface of the heater pipe; the air-temperature preheater 12 is an aluminum fin tube heat exchanger, which is placed in the induced draft pipe 5, and the LNG flows in the preheater pipe.

[0042] The air circulation subsystem includes an induced draft duct 5, an air supply duct 6, a return air duct 9, an exhaust duct 10, an air hood 8 and a fan 15; the outlet of the induced draft duct 5 is connected to the inlet of the air supply duct 6, the outlet of the air supply duct 6 is connected to the lower end of the air hood 8, the inlet of the return air duct 9 is connected to the top of the air hood 8, and the outlet of the return air duct 9 is respectively connected to the inlet of the exhaust duct 10 and the inlet of the air supply duct 6; the outlet of the exhaust duct 10 and the inlet of the induced draft duct 5 are connected to the atmospheric environment; the fan 15 is placed at the inlet of the air supply duct 6; the fan 15 is a variable frequency explosion-proof fan; the air temperature vaporizer 18 is placed in the center of the air hood 8;

[0043] The induced air duct 5, the supply air duct 6 and the exhaust air duct 10 are respectively provided with a first electric air valve 14, a second electric air valve 16 and a third electric air valve 21; the inlet of the induced air duct 5 and the outlet of the exhaust air duct 10 are respectively provided with rainproof shutters 11; the bottom of the induced air duct 5 is provided with an S-shaped water seal 13, the bottom slope is 0.1%, and the slope is towards the S-shaped water seal 13; the outlet of the supply air duct 6 is provided with an air supply port 17; the inlet elbow of the return air duct 9 is provided with a guide plate 19, the horizontal section of the return air duct 9 has a slope of 0.1%, and the slope is towards the air temperature gasifier 18, and the high point of the horizontal section of the return air duct 9 is provided with a natural gas leak alarm 20;

[0044] The LNG outlet of the LNG storage tank 22 is connected to the inlet of the LNG bypass pipe 23 and the LNG inlet of the air-temperature vaporizer 18 respectively; the outlet of the LNG bypass pipe 23 is connected to the LNG inlet of the air-temperature preheater 12; the LNG outlet of the air-temperature preheater 12 is connected to the inlet of the LNG output pipe 24; the outlet of the LNG output pipe 24 is connected to the LNG inlet of the air-temperature vaporizer 18, and the natural gas outlet of the air-temperature vaporizer 18 is connected to the gas supply network 26 through the natural gas pipe 25. A temperature measuring device 29 and a closed full-open safety valve 30 are provided; a check valve 28 is provided on the branch lines connecting the LNG outlet of the LNG storage tank 22 to the LNG inlet of the air-temperature preheater 12 and the air-temperature vaporizer 18, respectively, to ensure that there will be no backflow when the pressure in the pipeline is abnormal; an emergency shut-off valve 27 is provided on the LNG outlet pipeline of the LNG storage tank 22, and the distance between the emergency shut-off valve 27 and the air-temperature vaporizer 18 is not less than 15 meters, and the emergency shut-off valve 27 is interlocked with the natural gas leak alarm 20 and the temperature measuring device 29, respectively.

[0045] like Figure 2-6 As shown, the material of the wind hood 8 is a stainless steel plate, and the top projection of the wind hood 8 is a square. The south side and the top of the wind hood 8 are provided with a plurality of square holes of equal area to install single-layer tempered white glass 31, and the north side of the wind hood 8 is provided with a closed inspection door 32. The bottom of the wind hood 8 is provided with an S-shaped water seal 13, and the bottom slope is 0.1%, sloping towards the S-shaped water seal 13. The wind hood 8 is fixedly supported by a bracket 7; the closed inspection door 32 is a swing door that opens outwards; the bracket 7 is made of stainless steel, the top of the bracket 7 is welded to the bottom of the wind hood 8, and the bottom of the bracket 7 is fixed to the ground by anchor bolts; there are four brackets 7, and the top projection connecting line is a square, forming a concentric square with the top projection of the wind hood 8.

[0046] The above-mentioned LNG frost suppression and efficiency enhancement air bath gasification method using a solar heat pump and air circulation:

[0047] When the operation starts, the first electric air valve 14, the second electric air valve 16, the fan 15 and the compressor 2 are opened, and the third electric air valve 21 is closed. The ambient air enters the induced draft duct 5 under the action of the fan 15, flows through the air-temperature preheater 12 to heat the input LNG, and the condensed water condensed on the surface of the air-temperature preheater 12 during the heating process is discharged through the S-shaped water seal 13. The dehumidified and cooled air flows through the air condenser 3 to be heated, and then enters the wind hood 8 through the air supply port 17, flows through the air-temperature vaporizer 18 to heat the input LNG to vaporize it, and the condensed water condensed on the surface of the air-temperature vaporizer 18 during the vaporization process is discharged through the S-shaped water seal 13. The air cooled and further dried by the air-temperature vaporizer 18 flows through the return air duct 9 into the air supply duct 6 to form an air circulation; after the air volume in the air supply duct 6 stabilizes, the first electric air valve 14 is closed;

[0048] The refrigerant releases the heat absorbed by the heat collecting evaporator 1 from the solar radiation and the ambient air to the air in the air supply pipe 6 through the air condenser 3; the solar energy enters the wind hood 8 through the single-layer tempered white glass 31 on the south side and top surface of the wind hood 8, generating a greenhouse effect and heating the air in the wind hood 8;

[0049] A portion of the LNG flowing out of the LNG storage tank 22 enters the air-temperature preheater 12 to absorb the heat of the air in the induced draft pipe 5. By controlling the flow rate of LNG entering the air-temperature preheater 12, it is ensured that the LNG flowing out of the air-temperature preheater 12 is always in liquid state; the LNG preheated by the air-temperature preheater 12 is merged into another stream of LNG flowing out of the LNG storage tank 22, and is input into the air-temperature vaporizer 18 for vaporization, and then enters the gas supply network 26 for supply to users after pressure regulation, metering, and odorization;

[0050] When the air-temperature vaporizer 18 is under maintenance, the emergency shut-off valve 27 is closed, and the first electric air valve 14 , the third electric air valve 21 and the closed maintenance door 32 are opened to ensure the air quality in the air hood 8 .

[0051] The present invention can be applied to LNG receiving terminals, LNG satellite stations, LNG gasification stations and other places, and is also suitable for various occasions of air-bath gasification of low-temperature media.

[0052] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation, characterized in that: The system comprises a direct expansion solar heat pump, an air circulation subsystem, an air-temperature preheater (12), an air-temperature vaporizer (18), an LNG storage tank (22) and a gas supply network (26); In the direct expansion solar heat pump, a heat collecting evaporator (1), a compressor (2), an air condenser (3) and an expansion valve (4) are connected in sequence through pipelines to form a closed refrigerant circulation path; The heat collecting evaporator (1) is a bare plate type flat plate heat collector, comprising a refrigerant coil and a base plate; The LNG outlet of the LNG storage tank (22) is respectively connected to the inlet of the LNG bypass pipe (23) and the LNG inlet of the air-temperature vaporizer (18); the outlet of the LNG bypass pipe (23) is connected to the LNG inlet of the air-temperature preheater (12); the LNG outlet of the air-temperature preheater (12) is connected to the inlet of the LNG output pipe (24); the outlet of the LNG output pipe (24) is connected to the LNG inlet of the air-temperature vaporizer (18); the natural gas outlet of the air-temperature vaporizer (18) is connected to the gas supply network (26) via a natural gas pipe (25); and the natural gas pipe (25) is provided with a temperature measuring device (29) and a closed full-lift safety valve (30); The air circulation subsystem comprises an induced draft duct (5), an air supply duct (6), a return air duct (9), an exhaust duct (10), a hood (8) and a fan (15); the outlet of the induced draft duct (5) is connected to the inlet of the air supply duct (6), the outlet of the air supply duct (6) is connected to the lower end of the hood (8), the inlet of the return air duct (9) is connected to the top of the hood (8), and the outlet of the return air duct (9) is respectively connected to the inlet of the exhaust duct (10) and the inlet of the air supply duct (6); the outlet of the exhaust duct (10) and the inlet of the induced draft duct (5) are connected to the atmospheric environment; the fan (15) is placed at the inlet of the air supply duct (6); the air temperature vaporizer (18) is placed in the center of the hood (8); The air condenser (3) and the air-temperature vaporizer (18) share a fan (15).

2. According to claim 1, an LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that: The air condenser (3) is a surface heater placed in the air supply pipe (6). The refrigerant flows in the heater pipe, and the air is pressurized by the fan (15) and forced to flow through the outer surface of the heater pipe.

3. According to claim 1, the LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that: The air-temperature preheater (12) is an aluminum fin tube heat exchanger, which is placed in the induced draft pipe (5), and LNG flows in the preheater pipe.

4. According to claim 1, the LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that: The induced air duct (5), the supply air duct (6) and the exhaust air duct (10) are respectively provided with a first electric air valve (14), a second electric air valve (16) and a third electric air valve (21); the inlet of the induced air duct (5) and the outlet of the exhaust air duct (10) are respectively provided with rainproof shutters (11); the bottom of the induced air duct (5) is provided with an S-shaped water seal (13), the bottom slope is 0.1%, and the slope is towards the S-shaped water seal (13); the outlet of the supply air duct (6) is provided with an air supply port (17); the inlet elbow of the return air duct (9) is provided with a guide plate (19), the horizontal section of the return air duct (9) has a slope of 0.1%, and the slope is towards the air temperature gasifier (18), and a natural gas leakage alarm (20) is provided at the high point of the horizontal section of the return air duct (9).

5. According to claim 1, the LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that: A check valve (28) is provided on the branch lines connecting the LNG outlet of the LNG storage tank (22) to the LNG inlet of the air-temperature preheater (12) and the air-temperature vaporizer (18) to ensure that there will be no backflow when the pressure in the pipeline is abnormal; an emergency shut-off valve (27) is provided on the LNG outlet pipeline of the LNG storage tank (22), and the distance between the emergency shut-off valve (27) and the air-temperature vaporizer (18) is not less than 15 meters. The emergency shut-off valve (27) is interlocked with the natural gas leak alarm (20) and the temperature measuring device (29), respectively.

6. According to claim 1, the LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that: The wind hood (8) is made of a stainless steel plate. The wind hood (8) is square in top view. A plurality of square holes of equal area are opened on the south side and the top of the wind hood (8) to install single-layer tempered white glass (31). A sealed inspection door (32) is provided on the north side of the wind hood (8). An S-shaped water seal (13) is provided at the bottom of the wind hood (8). The bottom slope is 0.1% and slopes toward the S-shaped water seal (13). The wind hood (8) is fixedly supported by a bracket (7). The enclosed inspection door (32) is a swing door that opens outwards; The bracket (7) is made of stainless steel, the top of the bracket (7) is welded to the bottom of the wind shield (8), and the bottom of the bracket (7) is fixed to the ground by anchor bolts; there are four brackets (7), and the connecting line of their top-view projections is a square, forming a concentric square with the top-view projection of the wind shield (8).

7. According to claim 1, the LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation is characterized in that: The fan (15) is a variable frequency explosion-proof fan.

8. A gasification method of the LNG frost suppression and efficiency enhancement air bath gasification system using a solar heat pump and air circulation according to claim 1, characterized in that: When the operation starts, the first electric air valve (14), the second electric air valve (16), the fan (15) and the compressor (2) are opened, and the third electric air valve (21) is closed. The ambient air enters the induced draft duct (5) under the action of the fan (15), flows through the air temperature preheater (12) to heat the input LNG. During the heating process, the condensed water condensed on the surface of the air temperature preheater (12) is discharged through the S-shaped water seal (13). The dehumidified and cooled air flows through the air condenser (3). The LNG is heated and then enters the air hood (8) through the air supply port (17), flows through the air temperature vaporizer (18) to heat the input LNG and vaporize it. During the vaporization process, the condensed water condensed by the hot air on the surface of the air temperature vaporizer (18) is discharged through the S-shaped water seal (13). The air cooled and further dried by the air temperature vaporizer (18) flows through the return air duct (9) and enters the air supply duct (6) to form an air circulation. After the air volume in the air supply duct (6) is stabilized, the first electric air valve (14) is closed. The refrigerant releases the heat absorbed by the heat collecting evaporator (1) from solar radiation and ambient air to the air in the air supply pipe (6) through the air condenser (3); the solar energy enters the wind hood (8) through the single-layer tempered white glass (31) on the south side and top surface of the wind hood (8), generating a greenhouse effect and heating the air in the wind hood (8); A portion of the LNG flowing out of the LNG storage tank (22) enters the air-temperature preheater (12) to absorb heat from the air in the draft pipe (5), and the LNG flowing out of the air-temperature preheater (12) is controlled to ensure that the LNG flowing out of the air-temperature preheater (12) is always in a liquid state; the LNG preheated by the air-temperature preheater (12) is merged into another stream of LNG flowing out of the LNG storage tank (22), and is input into the air-temperature vaporizer (18) for vaporization, and then enters the gas supply network (26) for supply to users after pressure regulation, metering, and odorization; When the air-temperature vaporizer (18) is under maintenance, the emergency shut-off valve (27) is closed, and the first electric air valve (14), the third electric air valve (21) and the sealed maintenance door (32) are opened to ensure the quality of air in the air hood (8).

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