A low-energy-consuming LNG gasification system for a distributed natural gas power station

Abstract

The present invention relates to an LNG gasification system with low energy consumption for a distributed natural gas power station, which is characterized in that: the outlet of the LNG gasification station is connected to the inlet of the LNG booster pump, the outlet of the LNG booster pump is connected in parallel with the inlet of the air-cooled vaporizer and the gas inlet of the water bath heat exchanger, the outlet of the air-cooled vaporizer and the gas outlet of the water bath heat exchanger are connected in parallel through pipelines and then connected to the inlet of the pressure regulating and metering device, and the outlet of the pressure regulating and metering device is connected to the gas inlet of the natural gas generator set; the cylinder jacket hot water outlet of the natural gas generator set is connected to the first inlet of the plate heat exchanger, the first outlet of the plate heat exchanger is connected to the cylinder jacket cooling water inlet of the natural gas generator, forming a primary water circulation system; the water outlet of the water bath heat exchanger is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the second inlet of the plate heat exchanger, the second outlet of the plate heat exchanger is connected to the water inlet of the water bath heat exchanger, and a natural gas boiler is provided in parallel with the plate heat exchanger, forming a secondary water circulation system. This system reduces the gasification cost.

Description

Technical Field

[0001] The invention belongs to the technical field of distributed rapid natural gas power generation, and in particular relates to a low-energy-consumption LNG gasification system of a distributed natural gas power station. Background Art

[0002] The LNG gasification of existing conventional LNG receiving terminals usually uses ORV (open-frame seawater gasifier), SCV (submerged combustion gasifier), IFV (intermediate medium gasifier) and other equipment to gasify LNG, which consumes a lot of energy. However, the generator sets of existing large-scale natural gas power plants (power plants above 900MW) will generate a lot of waste heat, and the recovery and utilization of waste heat can save energy. For example, the publication number is: CN210033658U, and the name is: Comprehensive utilization system of waste heat of large-scale biogas generator sets. A system for treating organic fertilizer using waste heat is disclosed. The publication number is: CN205135813U, and the name is: A system for realizing LNG gasification in distributed energy stations. This patent discloses a technology for gasifying LNG by recovering waste heat from high-temperature flue gas of gas turbines and steam turbines.

[0003] However, there are few practical applications of using the waste heat of generator sets for LNG gasification between existing large-scale natural gas power plants and LNG receiving terminals. Therefore, how to reduce the energy consumption of LNG gasification and use the waste heat of generator sets as energy for LNG gasification has very important practical value. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a low-energy consumption LNG gasification system for distributed natural gas power stations that can utilize the waste heat of the generator cylinder jacket and the heat of the ambient air, thereby significantly reducing the LNG gasification cost.

[0005] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0006] A low-energy LNG gasification system for a distributed natural gas power station, characterized by comprising an LNG gasification station, an LNG booster pump, an air-temperature gasifier, a water bath heat exchanger, a circulating water pump, a natural gas boiler, a plate heat exchanger, an air cooler, a natural gas generator set and a pressure regulating and metering device;

[0007] The LNG gasification station is used to receive and temporarily store LNG. The outlet of the LNG gasification station is connected to the inlet of the LNG booster pump through a pipeline. The outlet of the LNG booster pump is connected to the inlet of the air-temperature gasifier and the gas inlet of the water bath heat exchanger through a pipeline. The outlet of the air-temperature gasifier and the gas outlet of the water bath heat exchanger are connected to the inlet of the pressure regulating and metering device through a pipeline. The outlet of the pressure regulating and metering device is connected to the gas inlet of the natural gas generator set through a pipeline.

[0008] The hot water outlet of the cylinder liner of the natural gas generator set is connected to the first inlet of the plate heat exchanger through a pipeline; the first outlet of the plate heat exchanger is connected to the cylinder liner cooling water inlet of the natural gas generator through a pipeline; an air cooler is connected in series on the pipeline connecting the plate heat exchanger and the cylinder liner of the natural gas generator, forming a primary circulating water system as a whole;

[0009] The water outlet of the water bath heat exchanger is connected to the inlet of the circulating water pump through a pipeline, the outlet of the circulating water pump is connected to the second inlet of the plate heat exchanger through a pipeline, and the second outlet of the plate heat exchanger is connected to the water inlet of the water bath heat exchanger through a pipeline; a three-way joint is provided on the connecting pipeline between the circulating water pump and the plate heat exchanger, and a three-way joint is also provided on the connecting pipeline between the plate heat exchanger and the water bath heat exchanger. A natural gas boiler is connected between the two three-way joints through a pipeline, forming a secondary circulating water system as a whole;

[0010] Cut-off valves are provided at both the inlet and outlet of the air temperature type vaporizer; cut-off valves are provided at both the gas inlet and gas outlet of the water bath heat exchanger; the air temperature type vaporizer and the water bath heat exchanger form an opening and closing interlock control through the cut-off valves; cut-off valves are provided at both the water inlet and water outlet of the natural gas boiler.

[0011] Further: A temperature control meter is provided at the cylinder liner cooling water inlet of the natural gas generator set; a temperature control three-way valve is installed at a position close to the cylinder liner cooling water inlet of the natural gas generator on the connecting pipeline between the cylinder liner cooling water inlet of the natural gas generator and the first outlet of the plate heat exchanger. The temperature control three-way valve is communicated with the connecting pipeline between the cylinder liner hot water outlet of the natural gas generator and the first inlet of the plate heat exchanger through a branch pipeline; the temperature control meter cooperates with the temperature control three-way valve to control the action of the temperature control three-way valve through a temperature control signal, forming a control loop for controlling and adjusting the temperature of the cooling water of the primary circulating water.

[0012] Further: The circulating water pump in the secondary circulating water system adopts a combined structure of a variable frequency pump and a fixed frequency pump, and an ultrasonic flowmeter is provided at the rear end of the installation position of the circulating water pump on the corresponding connecting pipeline.

[0013] Further: A thermometer is installed on the pipeline connecting the outlet of the air temperature type vaporizer and the inlet of the pressure regulating and metering device at the common connection of the gas outlet of the water bath heat exchanger; a flow regulating valve is provided on the pipeline connecting the first outlet of the plate heat exchanger and the water inlet of the water bath heat exchanger.

[0014] Further: A buffer water tank is provided on the pipeline at the front end of the circulating water pump in the secondary circulating water system, and an exhaust device located at the high point and a sewage discharge device located at the low point are provided on the buffer water tank and the water bath heat exchanger.

[0015] Furthermore: A softened water make-up device is connected to the pipeline of the secondary circulating water system, and a drain valve is provided. A filter and a check valve are provided in front of the circulating water pump.

[0016] Furthermore: The circulating medium in both the primary circulating water system and the secondary circulating water system is softened water.

[0017] Furthermore: Both the plate heat exchanger and the water bath heat exchanger are made of 304 alloy material.

[0018] Furthermore: Temperature, pressure, and flow display devices are installed on the pipelines before and after the circulating water heat exchange in both the primary circulating water system and the secondary circulating water system.

[0019] Advantages and positive effects of the present invention:

[0020] 1. The present invention uses a water bath heat exchanger and a plate heat exchanger to form two circulating water systems to gasify LNG. Specifically, the plate heat exchanger is connected to the generator cylinder liner to form a primary circulating water system, and the water bath heat exchanger is connected to the plate heat exchanger to form a secondary circulating water system. The primary circulating water system takes out the heat of the cooling water of the generator cylinder liner through the primary circulating water, exchanges heat through the plate heat exchanger, and transfers the heat to the circulating water in the secondary circulating water system, realizing the cooling and reflux of the cooling water. The secondary circulating water that absorbs heat gasifies LNG through the water bath heat exchanger, realizing the utilization of the waste heat of power generation. In addition, the air-cooled heat exchanger can directly gasify LNG. Furthermore, the natural gas boiler is connected in parallel to the water bath heat exchange system as a backup gasification method. In practical applications, a choice can be made among the three gasification methods, and the actual operation cost is reduced to the greatest extent.

[0021] 2. In the cylinder liner circulating water system of the natural gas generator set, that is, in the primary circulating water system, the present invention adopts a series connection structure of air cooling and a plate heat exchanger, and a temperature protection device is set in the series-connected primary water circulation to ensure that at least one cooling method remains in operation during the operation of the natural gas generator set, and the temperature of the cylinder liner return water is stabilized between 70 - 75°C. Description of the Drawings

[0022] Figure 1 is the overall connection schematic diagram of the present invention;

[0023] Figure 2 is the connection schematic diagram of the primary circulating water system of the present invention. Detailed Embodiments

[0024] The structure of the present invention will be further described below with reference to the drawings and through embodiments. It should be noted that this embodiment is narrative rather than restrictive.

[0025] A low - energy - consumption LNG gasification system for a distributed natural gas power station, which is used to realize the gasification of liquefied natural gas. Heat is required during the gasification process of LNG from - 160°C to 15°C. The gasification of LNG is divided into two stages. The first stage is the process from liquid LNG to gaseous LNG, and in this process, latent heat of vaporization and sensible heat need to be provided to LNG. The second stage is the process of heating the low - temperature gas to a high - temperature gas, and the required heat needs to be calculated according to the temperature difference between the specific heat capacity of LNG and the target temperature. The latent heat of vaporization of methane is 590 KJ / KG, the sensible heat is 300 KJ / KG, the specific heat capacity is 2.156 KJ / KG.K, and the density of LNG is considered according to 450 m3 / h. The heat value required for gasification per hour is calculated according to the mass flow rate of LNG.

[0026] The gasification of LNG is realized through a heat exchanger, and the heat transfer amount of the heat exchanger is calculated based on the chemical engineering fluid heat transfer formula. According to the principle of conservation of energy, the cold fluid absorbs the heat of the hot fluid; the hot fluid transfers heat to the cold fluid, as shown in the following formula.

[0027] Q = WhCph(T1 - T2)=WcCpc (t2 - t1)

[0028] In the formula, Q----the heat load of the heat exchanger, kj / h or W; Wh is the mass flow rate of the hot fluid, kg / h; Wc is the mass flow rate of the cold fluid, kg / h; Cph is the specific heat capacity of the hot fluid, kj / (kg.°C); Cpc is the specific heat capacity of the cold fluid, kj / (kg.°C); T--the temperature of the hot fluid, °C; t--the temperature of the cold fluid, °C

[0029] Based on the above heat transfer principle, the structural composition of the low - energy - consumption LNG gasification system of this distributed natural gas power station is shown in Figure 1-2 ,

[0030] It mainly includes an LNG gasification station 1, an LNG booster pump 2, an air - cooled vaporizer 4, a water - bath heat exchanger 3, a circulating water pump 11, a natural gas boiler 10, a plate heat exchanger 9, an air - cooler 8, a natural gas generator set 7, a pressure - regulating and metering device 6. The pressure - regulating and metering are currently standardized equipment and are provided as a complete set by the complete - set manufacturer.

[0031] The LNG gasification station is used to receive and temporarily store LNG. The outlet of the LNG gasification station is connected to the inlet of the LNG booster pump through a pipeline. The outlet of the LNG booster pump is connected in parallel to the inlet of the air - cooled vaporizer and the gas inlet of the water - bath heat exchanger through pipelines. The outlet of the air - cooled vaporizer and the gas outlet of the water - bath heat exchanger are connected in parallel and then connected to the inlet of the pressure - regulating and metering device through a pipeline. The outlet of the pressure - regulating and metering device is connected to the gas inlet of the natural gas generator set. It realizes the gasification of LNG and supplies gas to the generator set.

[0032] The hot water outlet of the cylinder liner of the natural gas generator set is connected to the first inlet of the plate heat exchanger through a pipeline (hot water pipeline); the first outlet of the plate heat exchanger is connected to the cylinder liner cooling water inlet of the natural gas generator through a pipeline (cold water pipeline). An air cooler is connected in series on the pipeline connecting the plate heat exchanger and the cylinder liner of the natural gas generator. In the non-operating state or in case of failure of the plate heat exchanger, the series-connected air cooler can keep the cylinder liner water of the generator cooled normally and protect the normal operation of the generator.

[0033] The water outlet of the water bath heat exchanger is connected to the inlet of the circulating water pump through a pipeline, the outlet of the circulating water pump is connected to the second inlet of the plate heat exchanger through a pipeline, and the second outlet of the plate heat exchanger is connected to the water inlet of the water bath heat exchanger through a pipeline; a three-way joint is provided on the connecting pipeline between the circulating water pump and the plate heat exchanger, and a three-way joint is also provided on the connecting pipeline between the plate heat exchanger and the water bath heat exchanger. A natural gas boiler is connected between the two three-way joints through a pipeline.

[0034] As shown in the appendix Figure 2 As shown, the natural gas generator set, the plate heat exchanger and the air cooler are connected through pipelines to form a primary circulating water system. A temperature control three-way valve 18 is installed at a position close to the cylinder liner cooling water inlet of the natural gas generator on the connecting pipeline between the cylinder liner cooling water inlet of the natural gas generator and the first outlet of the plate heat exchanger. The temperature control three-way valve is communicated with the connecting pipeline between the hot water outlet of the cylinder liner of the natural gas generator and the first inlet of the plate heat exchanger through a branch pipeline. The temperature control three-way valve is used to control the proportion adjustment of hot water outlet, cooling water and direct return cylinder liner hot water.

[0035] In the primary circulating water system, a temperature control meter 17 is provided at the cylinder liner cooling water inlet of the natural gas generator set to detect the return water temperature of the cooling water, so that the return water temperature of the cooling water is controlled between 70°C and 75°C. The temperature control signal of the temperature control meter is connected to the above-mentioned temperature control three-way valve to form a control loop for temperature control and adjustment of the cooling water in the primary circulating water. The proportion of hot water return and cooling water is adjusted through the temperature control three-way valve. The temperature control valve is located on the return pipeline of the hot water outlet of the cylinder liner water. The return pipeline (branch pipeline) is directly connected to the cooling water pipeline. By adjusting the opening of the temperature control valve, the proportion of hot water return and cooling water is adjusted. In addition, when the temperature control meter detects that the temperature of the cylinder liner cooling water inlet reaches 75°C, the air cooler is started to reduce the temperature of the cylinder liner cooling water.

[0036] The water bath heat exchanger, the circulating water pump, the plate heat exchanger and the natural gas boiler are connected by pipelines to form a secondary circulating water system. Among them, the circulating water pump is set as a combination of a variable frequency pump and a fixed frequency pump, and an ultrasonic flowmeter is designed at the rear end of the installation position of the circulating water pump on the corresponding pipeline to realize the adjustment of the flow rate of the secondary circulating water system within the full range. Temperature monitoring measures are set after the LNG is heated and vaporized by the water bath heat exchanger. A thermometer 5 is installed on the pipeline connecting the outlet of the air temperature vaporizer and the gas outlet of the water bath heat exchanger to the inlet of the pressure regulating and metering device, for measuring the temperature of the vaporized LNG output. In this embodiment, the temperature of the vaporized natural gas is set to 10°C. When the temperature of the heated output natural gas is lower than 10°C, the variable frequency pump is started first to increase the flow rate of the secondary circulating water. After the flow rate reaches the upper limit and the natural gas temperature still cannot reach 10°C, the natural gas boiler is started for heating. When the natural gas temperature is lower than 5°C, the ESD (Emergency Shut-off Valve) is triggered to stop the operation of the water bath heat exchanger and the LNG booster pump. A flow regulating valve 14 is further provided on the hot water return pipeline of the secondary circulating water system (i.e., the pipeline connecting the first outlet of the plate heat exchanger and the water inlet of the water bath heat exchanger) to realize the matching adjustment of the flow rate of the secondary circulating water and the vaporization flow rate of the LNG.

[0037] For the primary circulating water system, a plate heat exchanger is installed on each natural gas generator set; after considering the heat exchange efficiency of the plate heat exchanger and the heat loss of the circulating water pipeline, the heat load that can be provided by the cylinder jacket water of a single generator is calculated. The heat load of the LNG vaporization should be less than or equal to the heat load provided by the cylinder jackets of all distributed natural gas generator sets. Valves are provided on the inlet pipeline and the outlet pipeline of the primary circulating water of each generator set to adjust the quantity of the waste heat supply of the natural gas generator set; the cooling method of the cylinder jacket water of the generator set can be automatically switched between air cooling and primary circulating water cooling.

[0038] Temperature, pressure and flow display devices before and after heat exchange of the circulating water are provided on the primary circulating water system; temperature, pressure and flow display devices before and after heat exchange of the circulating water are provided on the secondary circulating water system. The temperature, pressure and flow devices are installed at different positions of the circulating water system according to different functions, for judging the physical state of the primary circulating water and the secondary circulating water before and after heat exchange, judging whether the heat exchange effect meets the requirements, and providing operation data reference for the operators.

[0039] The plate heat exchange material of the primary circulating water system is 304 alloy material; the material of the water bath heat exchanger is 304 alloy material. It can avoid the generation of rust blocks during long-term operation and affect the normal circulation flow of the circulating medium, which is beneficial to ensuring the heat exchange efficiency.

[0040] In the secondary circulating water system, a buffer water tank 15 is provided at the front end of the circulating water pump on the circulating water pipeline to protect the circulating water pump. High-point exhaust devices and low-point sewage discharge devices are provided for static equipment such as the buffer water tank and the water bath heat exchanger. The exhaust device can adopt an exhaust valve, and the sewage discharge device can adopt a sewage discharge valve.

[0041] The circulating medium in both the primary circulating water system and the secondary circulating water system uses softened water, which is beneficial to improving the heat exchange efficiency and reducing pipeline blockage. A softened water replenishing device 16 is provided in the secondary circulating water system to regularly replenish softened water into the secondary circulating water system. A filter 13 and a check valve 12 are provided in front of the circulating water pump to filter particulate matter that may exist in the circulating water system from damaging the pump and prevent the backflow of circulating water. A drain valve is provided on the pipeline of the secondary circulating water system to regularly detect the water quality.

[0042] The natural gas boiler in the secondary circulating water system is connected in parallel with the plate heat exchanger. Cut-off valves are provided at the inlet and outlet of the natural gas boiler, which can completely isolate the natural gas boiler from the system. The natural gas boiler can separately heat the secondary cycle to provide hot circulating water for the water bath heat exchanger. The secondary circulating water is connected to the circulating hot water at the inlet of the water bath heat exchanger after being heated by the natural gas boiler. The natural gas for heating and gasifying LNG by the natural gas boiler is only used during startup, when the ambient temperature is too low and the air-cooled vaporizer cannot ensure the temperature of the gasified natural gas, and when the cylinder jacket waste heat circulation of the natural gas generator set cannot operate normally.

[0043] The air-cooled vaporizer is connected in parallel with the water bath heat exchanger; cut-off valves are provided at both the inlet and outlet of the air-cooled vaporizer; cut-off valves are provided at both the inlet and outlet of the water bath heat exchanger. The air-cooled vaporizer and the water bath heat exchanger are provided with an interlock function, that is, when the cut-off valves at the inlet and outlet of the air-cooled vaporizer are in the open state, the cut-off valves at the inlet and outlet of the water bath heat exchanger are in the cut-off state, and vice versa. This prevents the simultaneous use of the two gasification methods, thereby preventing the gas pressure of the gasified natural gas from the air-cooled vaporizer and the water bath heat exchanger from being in series, causing potential safety hazards.

[0044] The working process of a low - energy - consumption LNG gasification system for a distributed natural gas power station is as follows: When the generator set starts, first consider using an air - temperature - type vaporizer to gasify and heat the LNG. When the outside ambient temperature is relatively low and the temperature of the gasified LNG output is less than 10°C, cut off the air - temperature - type vaporizer and start the natural gas boiler and the secondary circulating water system. Gasify and heat the LNG through boiler heating. When the generator set enters the normal working state, the cylinder jacket of the generator set generates waste heat. At this time, turn on the primary circulating water system and cut off the heat supply of the natural gas boiler. Transfer the waste heat of the cylinder jacket of the generator set to the LNG through the primary and secondary circulating water systems to gasify and heat the LNG, realizing the recovery and utilization of the waste heat of the generator set. When the waste heat supply of the cylinder jacket of the generator set is insufficient during the normal working state of the generator set, turn on the natural gas boiler to increase the hot water temperature of the secondary circulating water and ensure that the gasification temperature of the LNG reaches the required value. During the normal working process of the generator set, adjust the ratio of hot water return and cooling water through the temperature - controlled three - way valve in the primary circulating water system to control the inlet temperature of the cylinder jacket cooling water of the generator set. When the inlet temperature of the cylinder jacket cooling water of the generator set reaches the temperature upper limit, start the air cooler to reduce the temperature of the cylinder jacket cooling water. In addition, during the normal long - term continuous working process of the generator set, it is also necessary to regularly switch the working states of the air - temperature - type vaporizer and the water - bath heat exchanger to avoid failures caused by the long - term non - use of the heating branch of the air - temperature - type vaporizer.

[0045] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that within the spirit of the present invention and the appended claims, various substitutions, changes, and modifications are possible. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments and drawings.

Claims

1. A low-energy-consuming LNG gasification system for a distributed natural gas power station, characterized in that: It includes an LNG vaporization station, an LNG booster pump, an air-cooled vaporizer, a water bath heat exchanger, a circulating water pump, a natural gas boiler, a plate heat exchanger, an air cooler, a natural gas generator set, and a pressure regulating and metering device; The LNG vaporization station is used to receive and temporarily store LNG. The outlet of the LNG vaporization station is connected to the inlet of the LNG booster pump through a pipeline. The outlet of the LNG booster pump is connected in parallel to the inlet of the air-cooled vaporizer and the gas inlet of the water bath heat exchanger through pipelines. The outlet of the air-cooled vaporizer and the gas outlet of the water bath heat exchanger are connected in parallel through a pipeline and then connected to the inlet of the pressure regulating and metering device. The outlet of the pressure regulating and metering device is connected to the gas inlet of the natural gas generator set through a pipeline; The cylinder jacket hot water outlet of the natural gas generator set is connected to the first inlet of the plate heat exchanger through a pipeline; the first outlet of the plate heat exchanger is connected to the cylinder jacket cooling water inlet of the natural gas generator through a pipeline; an air cooler is connected in series on the pipeline connecting the plate heat exchanger and the cylinder jacket of the natural gas generator, forming a primary circulating water system as a whole; The water outlet of the water bath heat exchanger is connected to the inlet of the circulating water pump through a pipeline. The outlet of the circulating water pump is connected to the second inlet of the plate heat exchanger through a pipeline. The second outlet of the plate heat exchanger is connected to the water inlet of the water bath heat exchanger through a pipeline; a three-way joint is provided on the connecting pipeline between the circulating water pump and the plate heat exchanger, and a three-way joint is also provided on the connecting pipeline between the plate heat exchanger and the water bath heat exchanger. The two three-way joints are connected through a pipeline to a natural gas boiler, forming a secondary circulating water system as a whole; Cut-off valves are provided at both the inlet and outlet of the air-cooled vaporizer; cut-off valves are provided at both the gas inlet and gas outlet of the water bath heat exchanger; the air-cooled vaporizer and the water bath heat exchanger form an opening and closing interlock control through the cut-off valves; cut-off valves are provided at both the water inlet and water outlet of the natural gas boiler.

2. The LNG gasification system with low energy consumption for a distributed natural gas power station according to claim 1, characterized in that: A temperature control meter is provided at the cylinder jacket cooling water inlet of the natural gas generator set; a temperature control three-way valve is installed at a position close to the cylinder jacket cooling water inlet of the natural gas generator on the connecting pipeline between the cylinder jacket cooling water inlet of the natural gas generator and the first outlet of the plate heat exchanger. The temperature control three-way valve is connected to the connecting pipeline between the cylinder jacket hot water outlet of the natural gas generator and the first inlet of the plate heat exchanger through a branch pipeline; the temperature control meter cooperates with the temperature control three-way valve to control the action of the temperature control three-way valve through a temperature control signal, forming a control loop for controlling and adjusting the temperature of the cooling water of the primary circulating water.

3. The low-energy-consumption LNG gasification system of the distributed natural gas power station according to claim 1, characterized in that: The circulating water pump in the secondary circulating water system adopts a combined structure of a variable-frequency pump and a fixed-frequency pump, and an ultrasonic flowmeter is provided at the rear end of the installation position of the circulating water pump on the corresponding connecting pipeline.

4. The LNG gasification system with low energy consumption for a distributed natural gas power station according to claim 3, characterized in that: A thermometer is installed on the pipeline connecting the outlet of the air-cooled vaporizer and the gas outlet of the water bath heat exchanger to the inlet of the pressure regulating and metering device; a flow regulating valve is provided on the pipeline connecting the first outlet of the plate heat exchanger and the water inlet of the water bath heat exchanger.

5. The LNG gasification system with low energy consumption for a distributed natural gas power station according to claim 1, characterized in that: A buffer water tank is provided on the pipeline at the front end of the circulating water pump in the secondary circulating water system, and an exhaust device located at the high point and a sewage discharge device located at the low point are provided on the buffer water tank and the water bath heat exchanger.

6. The low-energy-consumption LNG gasification system of the distributed natural gas power station according to claim 1, wherein: A softened water replenishing device is connected to the pipeline of the secondary circulating water system and a drain valve is provided. A filter and a check valve are provided in front of the circulating water pump.

7. The low-energy consumption LNG gasification system of the distributed natural gas power station according to claim 1, wherein: The circulating medium in both the primary circulating water system and the secondary circulating water system is softened water.

8. The low-energy consumption LNG gasification system of the distributed natural gas power station according to claim 1, characterized in that: Both the plate heat exchanger and the water bath heat exchanger are made of 304 alloy material.

9. The LNG gasification system with low energy consumption for a distributed natural gas power station according to claim 1, wherein: Temperature, pressure, and flow rate display devices are installed on the pipelines before and after the circulating water heat exchange in both the primary circulating water system and the secondary circulating water system.

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