A non-frozen high-efficiency cold energy recovery system and method for low-temperature liquid gasification

Abstract

The application discloses a non-freezing and high-efficiency cold energy recovery system and method for low-temperature liquid gasification, which comprises an evaporator, a superheater and a regenerator. The evaporator realizes complete vaporization and superheating of the liquid phase through a plurality of recirculation gas streams from the low-temperature liquid itself. The superheater performs secondary heating on the vaporized gas by using a heat medium to generate a first-stage high-temperature backflow. The regenerator performs re-warming treatment on the temperature-reduced gas stream after heat exchange, so that the temperature-reduced gas stream reaches a thermodynamic state capable of re-entering the evaporator. The three parts of the system construct a closed gas phase circulation structure, cold energy can be recovered in multiple stages, the low-temperature liquid is completely isolated from the heat medium, and freezing is effectively avoided. By adjusting the circulation times and flow parameters, different temperature gas products can be output, and a cooling heat medium can be generated at the same time, and the system is widely applicable to the fields of LNG gasification, industrial refrigeration, cold chain logistics and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-temperature liquid gasification cold energy recovery, and in particular to a non-freezing high-efficiency cold energy recovery system and method for low-temperature liquid gasification. BACKGROUND

[0002] Low-temperature liquids (such as liquefied natural gas LNG, liquid nitrogen, liquid oxygen, etc.) are widely used in energy, cold chain, industrial manufacturing, and other fields, and must be gasified before use. A large amount of cold energy is released during this phase change process. If it can be efficiently recovered and utilized, it can significantly reduce energy consumption, improve the overall energy efficiency of the system, and be widely used in air conditioning, refrigeration, cold chain transportation, low-temperature storage, and other scenarios. However, due to the significant temperature difference between the low-temperature fluid (usually below -150°C) and the heat medium, the traditional cold energy recovery system faces two major problems: first, the heat medium is prone to freezing due to supercooling, causing system operation to be interrupted or even equipment to be damaged; second, the large temperature difference also significantly reduces the cold energy heat exchange efficiency, resulting in low energy utilization. This "high risk and low efficiency" structural bottleneck has become a key obstacle to the widespread application of low-temperature liquid cold energy. SUMMARY

[0003] To solve the problems in the prior art, the present application provides a non-freezing high-efficiency cold energy recovery system and method for low-temperature liquid gasification. By constructing a multi-stage heat exchange structure based on internal gas phase circulation, the low-temperature fluid and the external heat medium are thermodynamically completely isolated during the gasification process, thereby avoiding the problem of heat medium freezing caused by excessive temperature difference from the source. The system internally adopts a closed circulation loop combined with a multi-stage heat exchange mechanism, which ensures the heat exchange efficiency and operational stability while achieving step-by-step, controllable, and efficient recovery of cold energy.

[0004] The technical solutions of the present application are as follows:

[0005] In the first aspect of the present application, a non-freezing high-efficiency cold energy recovery system for low-temperature liquid gasification is provided, comprising:

[0006] An evaporator for receiving low-temperature liquid and completely gasifying and primary superheating the low-temperature liquid by multiple internal high-temperature circulating gases;

[0007] A superheater connected downstream of the evaporator for secondary heating of the gasified gas by an external heat medium, generating high-temperature circulating gas and returning to the evaporator;

[0008] A regenerator receiving low-temperature circulating gas after the evaporator releases heat, reheating the low-temperature circulating gas to a set temperature using a heat medium and returning to the evaporator inlet; the circulating gas completes at least two cycles between the evaporator and the regenerator, forming a circulation loop;

[0009] an output control module for outputting the circulating gas at a preheating temperature and controlling the output temperature of the heat medium.

[0010] In some embodiments of the present application, a plurality of high-temperature circulating gas channels and a plurality of low-temperature liquid channels are arranged in the evaporator, a plurality of low-temperature circulating gas channels and a plurality of heat medium channels are arranged in the regenerator, the high-temperature circulating gas channels and the low-temperature circulating gas channels are one-to-one corresponding and connected in series, the plurality of low-temperature liquid channels are arranged in parallel, and the plurality of heat medium channels are arranged in parallel.

[0011] In some embodiments of the present application, a gasification gas channel and a heat medium channel are arranged in the superheater, and the heat medium channel in the superheater is arranged in parallel with the heat medium channel in the regenerator.

[0012] In some embodiments of the present application, the number of cycles of the circulating gas is adjusted according to an external cold load, and the number of cycles is controlled to be 2-5 times.

[0013] In some embodiments of the present application, the heat medium adopts a low-freezing-point fluid, and the low-freezing-point fluid includes one or more of ethylene glycol solution, propane, R23, and R410A.

[0014] In some embodiments of the present application, the low-temperature liquid includes one or more of liquefied natural gas, liquid nitrogen, liquid oxygen, liquid hydrogen, and liquid helium.

[0015] In some embodiments of the present application, the output control module includes a collection device, a controller, and an execution mechanism, and the collection device and the execution mechanism are connected to the controller.

[0016] In some embodiments of the present application, the collection device includes a temperature sensor and a flow sensor, the execution mechanism includes a low-temperature liquid pump, a heat medium pump, and a heat medium regulating valve, the temperature sensor is arranged at a heat medium outlet of the superheater and a heat medium outlet of the regenerator, the flow meter is arranged at a gas outlet of the regenerator, the low-temperature liquid pump is arranged at a low-temperature liquid inlet of the evaporator, the heat medium pump is arranged on a heat medium pipeline, and the heat medium regulating valve is arranged at a heat medium inlet of the superheater.

[0017] In the second aspect of the present application, a working method of a non-frozen high-efficiency cold energy recovery system for gasification of low-temperature liquid is provided, which includes:

[0018] The low-temperature liquid enters the evaporator, and complete gasification and primary heating are completed by internal high-temperature circulating gas in the evaporator;

[0019] The gasification gas enters the superheater, exchanges heat with the heat medium, forms high-temperature circulating gas, and returns to the evaporator.

[0020] The high-temperature circulating gas heats the low-temperature liquid in the evaporator, and the low-temperature circulating gas after releasing part of the heat is heated by the regenerator and then enters the evaporator again. After multiple cycles, the gas is discharged from the gas outlet of the regenerator at the target temperature.

[0021] In some embodiments of the application, the flow rate at the regenerator gas outlet is obtained, and the frequency of the low-temperature liquid pump is adjusted according to the flow rate to limit the gas temperature at the outlet within a set range according to the end user demand;

[0022] The outlet temperature of the heat medium of the superheater is obtained, and the opening of the heat medium regulating valve is adjusted according to the temperature to ensure the stability of the outlet temperature of the heat medium;

[0023] According to the temperature demand on the load side, the frequency of the heat medium pump is adjusted with the outlet temperature of the heat medium of the regenerator as the feedback signal;

[0024] A temperature threshold is set, and when the outlet temperature of the heat medium of the superheater is lower than the threshold, a protection mechanism is started to prevent the system from freezing by switching the bypass at the low-temperature liquid inlet of the evaporator.

[0025] The one or more technical solutions of the application have the following beneficial effects:

[0026] (1) The application completely isolates the low-temperature liquid and the heat medium in physical space and thermodynamic path through the series connection of the evaporator, the superheater and the regenerator. The circulating gas as an intermediate carrier transfers cold energy, which avoids the freezing risk caused by the direct contact of the heat medium with the fluid below-150℃. The circulating gas completes the absorption of low-temperature cold energy in the evaporator, realizes the energy transfer in the medium-temperature section in the superheater, and recovers the cold energy in the regenerator; a multi-stage gas phase circulation structure is formed between the evaporator and the regenerator, and by adjusting the circulation number and flow parameters, the gas output temperature and the heat medium output temperature can be accurately controlled to meet the diversified scene demands of LNG filling and cold chain.

[0027] (2) The application significantly improves the phase change efficiency by setting multiple parallel low-temperature liquid channels and series high-temperature circulating gas channels in the evaporator to form counterflow heat exchange, which can realize the complete gasification of the low-temperature liquid; the parallel heat medium channels and series low-temperature circulating gas channels in the regenerator form a circulation loop, and after multiple cycles, the cold energy recovery is maximized.

[0028] (3) Compared with traditional liquid-liquid heat exchange or refrigerant systems, the present application replaces hot liquid contact with internal gas circulation, builds a temperature field distribution with thermal gradient buffering characteristics, reduces the risk of icing, and reduces the loss of invalid heat transfer, significantly improving the overall thermal efficiency of the system. In addition, the system supports flexible adjustment of the number and flow parameters of the circulation loop, and can freely set the cooling output temperature according to the target application, suitable for cold energy utilization requirements in multiple scenarios.

[0029] (4) The output control module of the present application includes an acquisition device, a controller and an execution mechanism, the acquisition device includes a temperature sensor and a flow sensor, the execution mechanism includes a low-temperature liquid pump, a heat medium pump and a heat medium regulating valve; can according to the temperature and flow data of low-temperature liquid inlet, the temperature and flow data of output heat medium, call control algorithm to adjust the low-temperature liquid supply flow rate, circulation gas flow rate and heat medium supply flow rate, on the premise of ensuring that the heat medium does not freeze, realize the closed loop accurate control to the target cold quantity output temperature and flow.

[0030] (5) The system of the present application adopts modular architecture and compact arrangement as a whole, has good engineering expandability and application adaptability. Its structural design is suitable for various working conditions, which is suitable for fixed station scenes such as port LNG receiving station and industrial filling terminal, and can also be expanded to be applied to mobile terminal such as ship-mounted and mobile cold source system. It has good performance in gasification efficiency, cold energy recovery rate and operation safety. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic diagram of the non-freezing high-efficiency cold energy recovery system for low-temperature liquid gasification of the present application;

[0032] Figure 2 is a structural diagram of the output control module of the present application.

[0033] In the figure: 1, evaporator; 101, gasification gas pipeline; 102, first high-temperature circulating gas pipeline; 103, first low-temperature circulating gas pipeline; 104, second high-temperature circulating gas pipeline; 105, second low-temperature circulating gas pipeline; 106, third high-temperature circulating gas pipeline; 107, third low-temperature circulating gas pipeline; 108, fourth high-temperature circulating gas pipeline; 109, fourth low-temperature circulating gas pipeline; 2, superheater; 3, regenerator; 4, three-way bypass valve; 5, heat medium regulating valve; 6, flow meter; 7, first temperature sensor; 8, second temperature sensor; 9, low-temperature liquid pump; 10, heat medium pump; 11, controller. DETAILED DESCRIPTION

[0034] The present application will be further described below in combination with the drawings and examples.

[0035] Example 1

[0036] In a typical embodiment of the present invention, a freeze-free, high-efficiency cold energy recovery system for cryogenic liquid vaporization is proposed, such as... Figure 1 As shown, it includes:

[0037] Evaporator 1 is used to receive cryogenic liquid and to completely vaporize and initially superheat the cryogenic liquid through multiple streams of internal high-temperature circulating gas.

[0038] Superheater 2 is connected downstream of evaporator 1. It reheats the vaporized gas through an external heat medium to generate high-temperature circulating gas and returns it to evaporator 1.

[0039] The regenerator 3 receives the low-temperature circulating gas after the evaporator 1 releases heat, and uses a heat medium to reheat the low-temperature circulating gas to a set temperature before returning it to the inlet of the evaporator 1; the circulating gas completes at least two cycles between the evaporator 1 and the regenerator 3 to form a circulation loop;

[0040] The output control module is used to output the circulating gas at the preheated temperature and control the output temperature of the heat medium.

[0041] The aforementioned system, through a series design of evaporator, superheater, and regenerator, completely isolates the cryogenic liquid from the heat transfer medium in both physical space and thermodynamic path. The circulating gas acts as an intermediate carrier to transfer cold energy, fundamentally avoiding the freezing risk caused by direct contact between the heat transfer medium and fluids below -150°C. The circulating gas completes cryogenic energy absorption (vaporization + primary superheating) in the evaporator, achieves mid-temperature energy transfer (generating high-temperature reflux) in the superheater, and recovers cold energy in the regenerator. A multi-stage gas-phase circulation structure is formed between the evaporator and regenerator. By adjusting the number of cycles and flow parameters, the gas output temperature and the heat transfer medium output temperature can be precisely controlled to meet the diverse needs of LNG refueling, cold chain, and other scenarios.

[0042] In this embodiment, the evaporator 1 is provided with multiple high-temperature circulating gas channels and multiple low-temperature liquid channels, and the regenerator 3 is provided with multiple low-temperature circulating gas channels and multiple heat medium channels. The high-temperature circulating gas channels and low-temperature circulating gas channels correspond one-to-one and are connected in series. The multiple low-temperature liquid channels are connected in parallel, and the multiple heat medium channels are connected in parallel.

[0043] By setting up multiple parallel low-temperature liquid channels and series high-temperature circulating gas channels in the evaporator to form countercurrent heat exchange, the phase change efficiency is significantly improved, and the complete vaporization of the low-temperature liquid can be achieved. In the regenerator, the parallel heating medium channels and series low-temperature circulating gas channels form a circulation loop, and after multiple cycles, the cold energy recovery is maximized.

[0044] Further, the superheater 2 is provided with a gasification gas channel and a heat medium channel, and the heat medium channel in the superheater 2 is provided in parallel with the heat medium channel in the regenerator.

[0045] By providing the heat medium channel in the superheater in parallel with the heat medium channel in the regenerator, the temperature drop of the heat medium is avoided. The parallel design allows independent adjustment of the flow of the two heat mediums, and when the load of the regenerator changes suddenly, the flow of the superheater can be reduced alone to prevent the outlet temperature from being too low.

[0046] In the embodiment, the circulation number of the circulating gas is adjusted according to the external cold load, and the circulation number is controlled to be 2-5 times.

[0047] In the embodiment, the heat medium adopts a low freezing point fluid, and the low freezing point fluid includes one or more of ethylene glycol solution, propane, R23, and R410A.

[0048] In the embodiment, the low-temperature liquid includes one or more of liquefied natural gas, liquid nitrogen, liquid oxygen, liquid hydrogen, and liquid helium.

[0049] In the embodiment, at least one of the evaporator, the superheater, and the regenerator adopts any one of the following structure forms: a plate-fin heat exchanger, a spiral-wound tube heat exchanger, a tube-shell heat exchanger, or a plate heat exchanger.

[0050] As shown in Figure 2 The output control module includes a collection device, a controller 11, and an execution mechanism, the collection device and the execution mechanism are connected with the controller 11, the collection device includes a temperature sensor and a flow sensor, and the execution mechanism includes a low-temperature liquid pump, a heat medium pump, and a heat medium adjusting valve.

[0051] Further, a first temperature sensor 7 is arranged at the heat medium outlet of the superheater, a second temperature sensor 8 is arranged at the heat medium outlet of the regenerator, the flow meter 6 is arranged at the gas outlet of the regenerator, the low-temperature liquid pump 9 is arranged at the low-temperature liquid inlet of the evaporator 1, the heat medium pump 10 is arranged on the heat medium pipeline, and the heat medium adjusting valve 5 is arranged at the heat medium inlet of the superheater 2.

[0052] The working process of the no-freezing high-efficiency cold energy recovery system for low-temperature liquid gasification provided in the embodiment is as follows:

[0053] In the embodiment, the low-temperature liquid pump 9 is arranged at the low-temperature liquid inlet of the evaporator 1, the heat medium pump 10 is arranged on the heat medium pipeline, and the heat medium adjusting valve 5 is arranged at the heat medium inlet of the superheater 2. Figure 1The number of cycles in the system is 4, and the low-temperature liquid is adjusted by the three-way bypass valve 4 and enters the low-temperature liquid flow channel of the evaporator. In the evaporator, the low-temperature liquid exchanges heat with the high-temperature circulating gas from the system, and the low-temperature liquid is completely gasified and preliminarily overheated to form gasification gas. The gasification gas enters the superheater 2 through the gasification gas pipeline 101, and in the superheater, the gasification gas is further heated by the external heat medium to form high-temperature circulating gas. The high-temperature circulating gas enters the evaporator 1 again through the first high-temperature circulating gas pipeline 102, and the high-temperature circulating gas is cooled to low-temperature circulating liquid in the evaporator 1. The low-temperature circulating liquid enters the regenerator 3 through the first low-temperature circulating gas pipeline 103, and in the regenerator 3, the low-temperature circulating liquid is reheated to the set temperature by the external heat medium and flows back to the evaporator 1 again. The low-temperature circulating liquid flows through the second high-temperature circulating gas pipeline 104, the evaporator 1, the second low-temperature circulating gas pipeline 105, the regenerator 3, the third high-temperature circulating gas pipeline 106, the evaporator 1, the third low-temperature circulating gas pipeline 107, the regenerator 3, the fourth high-temperature circulating gas pipeline 108, the evaporator 1, the fourth low-temperature circulating gas pipeline 109, and the regenerator 3. After four cycles in the evaporator 1 and the regenerator 3, the circulating gas is discharged from the gas outlet of the regenerator 3 for external use.

[0054] The heat medium is pumped by the heat medium pump 10 and enters the superheater 2 and the regenerator 3 to provide heat. The heat medium with reduced temperature is combined and used externally.

[0055] Typical implementation case: LNG is gasified in the evaporator 1, and then adjusted in temperature and energy circulation by the superheater 2 and the regenerator 3. The system automatically adjusts the number of cycles n according to the set output temperature (5-25℃). The superheater 2 and the regenerator 3 use 50% ethylene glycol heat medium with an initial temperature of -10℃, and the number of cycles is set to 3. In 12 hours of continuous operation, the cold energy recovery efficiency is more than 90%, the system runs smoothly, and no freezing phenomenon occurs, verifying its high efficiency and high reliability.

[0056] The application provides a non-freezing high-efficiency cold energy recovery system for low-temperature liquid gasification, which is the first to propose a systematic solution based on "gas circulation heat exchange + complete heat medium isolation + cold energy cascade utilization + modular structure", and builds a cold energy efficient utilization and freezing risk control system suitable for various low-temperature medium gasification processes. The heat medium and the low-temperature fluid are completely isolated through closed-loop gas circulation, eliminating the risk of icing at the source; a three-stage integrated structure of evaporator - superheater - regenerator is built to form a cold energy cascade utilization chain; an adjustable cycle number and temperature control mechanism is introduced to realize controllable output temperature and process adaptation; a modular compact structure is designed to adapt to multiple scenarios such as ports, filling stations, and ship-mounted systems; and a system-level intelligent control framework is built to integrate flow regulation, temperature monitoring, and feedback control strategies.

[0057] Embodiment 2

[0058] In a typical embodiment of the application, a working method of a non-freezing high-efficiency cold energy recovery system for low-temperature liquid gasification is provided, comprising:

[0059] The low-temperature liquid enters the evaporator 1, and complete gasification and primary heating are completed by the internal high-temperature circulating gas in the evaporator 1;

[0060] The gasification gas enters the superheater 2, exchanges heat with the heat medium, forms high-temperature circulating gas, and returns to the evaporator 1;

[0061] The high-temperature circulating gas heats the low-temperature liquid in the evaporator 1, and the low-temperature circulating gas after releasing part of the heat is heated by the regenerator 2 and then enters the evaporator again. After multiple cycles, the gas is discharged from the gas outlet of the regenerator at a target temperature.

[0062] Further, the control process of the system comprises:

[0063] The flow rate FT1 at the gas outlet of the regenerator is obtained, and the frequency of the low-temperature liquid pump is adjusted according to the flow rate to limit the gas temperature at the outlet within a set range according to the demand of the end user; and a PID control mode is adopted.

[0064] The heat medium outlet temperature TT1 of the superheater is obtained, and the opening degree of the heat medium regulating valve is adjusted according to the temperature to ensure the stability of the heat medium outlet temperature; and a PID control mode is adopted.

[0065] According to the temperature demand on the load side, the heat medium outlet temperature TT2 of the regenerator is taken as a feedback signal to adjust the frequency of the heat medium pump; and a double-variable decoupling algorithm is adopted to coordinate the heat medium temperatures of the superheater and the regenerator.

[0066] A temperature threshold is set, when the outlet temperature of the heat medium of the superheater is lower than the threshold, the protection mechanism is started, and the bypass switch at the low-temperature liquid inlet of the evaporator is started to prevent the system from freezing. Specifically, the minimum temperature of the outlet heat medium of the superheater is monitored in real time, when the minimum temperature is lower than the threshold, the protection mechanism is started, the protection mechanism realizes adaptive protection through the superceding control of the superheater and the bypass switch mechanism, through the starting of the superceding control, the heat medium pump runs at full speed, at the same time, through the bypass switch at the low-temperature liquid inlet of the evaporator, the low-temperature liquid flow into the evaporator is reduced, until the temperature is higher than the threshold safety margin, the normal control is restored.

[0067] The working method of the non-freezing and high-efficiency cold energy recovery system for low-temperature liquid gasification provided by the embodiment has the following advantages: supporting multi-target optimization control (temperature+flow); integrating freezing protection logic to prevent the system from freezing due to sudden change of low-temperature liquid load; being expandable to predictive control (MPC) or fuzzy logic control (FLC); being easy to integrate into a SCADA platform or a remote energy management system to realize multi-station cooperative scheduling and dynamic cold quantity allocation.

[0068] Although the specific embodiments of the present application are described above with reference to the accompanying drawings, the present application is not limited to the above embodiments, and various modifications or changes can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A freeze-free, high-efficiency cold energy recovery system for cryogenic liquid vaporization, characterized in that, include: An evaporator is used to receive cryogenic liquids and completely vaporize and initially superheat the cryogenic liquids through multiple streams of internal high-temperature circulating gas. The superheater, connected downstream of the evaporator, reheats the vaporized gas through an external heat medium to generate high-temperature circulating gas, which is then returned to the evaporator. The regenerator receives the low-temperature circulating gas after the evaporator releases heat, and uses a heat medium to reheat the low-temperature circulating gas to a set temperature before returning it to the evaporator inlet; the circulating gas completes at least two cycles between the evaporator and the regenerator to form a circulation loop; The evaporator is provided with multiple high-temperature circulating gas channels and multiple low-temperature liquid channels. The regenerator is provided with multiple low-temperature circulating gas channels and multiple heat medium channels. The high-temperature circulating gas channels and low-temperature circulating gas channels are one-to-one and connected in series. The multiple low-temperature liquid channels are connected in parallel. The multiple heat medium channels are connected in parallel. The superheater is provided with a vaporization gas channel and a heat medium channel. The heat medium channel in the superheater is connected in parallel with the heat medium channel in the regenerator. The parallel design allows for independent adjustment of the flow rates of the two heat mediums. The output control module is used to output the circulating gas at the preheated temperature and control the output temperature of the heat transfer medium. The output control module includes a data acquisition device, a controller, and an actuator, and the data acquisition device and the actuator are both connected to the controller. The data acquisition device includes a temperature sensor and a flow sensor, and the actuator includes a cryogenic liquid pump, a heat medium pump, and a heat medium regulating valve. The temperature sensor is located at the heat medium outlet of the superheater and the heat medium outlet of the regenerator. The flow sensor is located at the gas outlet of the regenerator. The cryogenic liquid pump is located at the cryogenic liquid inlet of the evaporator, the heat medium pump is located on the heat medium pipeline, and the heat medium regulating valve is located at the heat medium inlet of the superheater. The frequency of the cryogenic liquid pump is adjusted according to the flow rate, and the opening of the heat medium regulating valve is adjusted according to the temperature, with the heat medium outlet temperature of the regenerator as the feedback signal. Adjust the frequency of the heat transfer pump and use a two-variable decoupling algorithm to coordinate the heat transfer temperature of the superheater and regenerator; A temperature threshold is set. When the outlet temperature of the superheater's heat medium is lower than the threshold, a protection mechanism is activated. This prevents the system from freezing by switching the bypass at the evaporator's low-temperature liquid inlet. Specifically, the minimum temperature of the heat medium at the superheater outlet is monitored in real time. When the minimum temperature is lower than the threshold, the protection mechanism is activated. The protection mechanism achieves adaptive protection through override control and bypass switching of the superheater. By activating override control, the heat medium pump runs at full speed. At the same time, by switching the bypass at the evaporator's low-temperature liquid inlet, the flow rate of the low-temperature liquid entering the evaporator is reduced until the temperature is higher than the threshold safety margin, at which point normal control is restored.

2. The freeze-free, high-efficiency cold energy recovery system for cryogenic liquid vaporization as described in claim 1, characterized in that, The number of cycles of the circulating gas is adjusted according to the external cooling load, and the number of cycles is controlled between 2 and 5.

3. The freeze-free, high-efficiency cold energy recovery system for cryogenic liquid vaporization as described in claim 1, characterized in that, The heat transfer medium is a low freezing point fluid, which includes one or more of ethylene glycol solution, propane, R23, and R410A.

4. The freeze-free, high-efficiency cold energy recovery system for cryogenic liquid vaporization as described in claim 1, characterized in that, The cryogenic liquid includes one or more of liquefied natural gas, liquid nitrogen, liquid oxygen, liquid hydrogen, and liquid helium.

5. A method for operating a freeze-free, high-efficiency cold energy recovery system for cryogenic liquid vaporization as described in any one of claims 1-4, characterized in that, include: The low-temperature liquid enters the evaporator, where it undergoes complete vaporization and primary heating through internal high-temperature circulating gas. The vaporized gas enters the superheater, exchanges heat with the heat medium, forms a high-temperature circulating gas, and returns to the evaporator; High-temperature circulating gas heats the low-temperature liquid in the evaporator. After releasing some heat, the low-temperature circulating gas is heated by the regenerator and then re-enters the evaporator. After multiple cycles, the gas is discharged from the gas outlet of the regenerator at the target temperature.

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