A cold industrial park system based on LNG cold energy and its cooling method

Abstract

The present invention discloses a cold industrial park system based on LNG cold energy and a cooling method thereof. The system includes an LNG cold energy recovery module, an ice-making module, a cold storage module, a freeze-drying and quick-freezing module, and a heat pump module. The LNG cold energy recovery module includes an LNG heat exchanger and a circulating refrigerant heater. The circulating refrigerant heater outlet is connected to the LNG heat exchanger. The LNG heat exchanger outlet is divided into three paths, passing through the ice-making module, the cold storage module, and the freeze-drying and quick-freezing module respectively, and then connected to the inlet of the circulating refrigerant heater. The heat pump module includes a heat pump compressor, a heat pump expansion valve, and an evaporator connected in sequence, and the evaporator is connected to the water tank of the ice-making module. The two ends of the circulating refrigerant heater are respectively connected to the heat pump compressor and the heat pump expansion valve. The present invention uses LNG cold energy for users such as ice-making, cold storage, quick-freezing and freeze-drying, achieving efficient energy utilization and industrial integration, with strong universality and greater economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of LNG cold energy recovery and utilization, and in particular to a cold industrial park system based on LNG cold energy and a cooling method thereof. Background Art

[0002] Traditional LNG receiving stations primarily utilize cold energy for air separation and power generation, a single industry. Limited by scale, this results in low economic returns and overall low utilization rates for LNG cold energy. However, building a cold energy industrial park based on LNG cold energy and utilizing it for ice making, cold storage, quick freezing, freeze-drying, and other user needs will not only increase LNG cold energy utilization rates but also establish a complete cold energy utilization industry chain, foster internal circulation within the park, and form a regional cold energy cluster, resulting in higher economic and social benefits.

[0003] Chinese patent CN110513157B discloses a new energy-saving process and system for LNG receiving stations. This system replaces the open-frame seawater vaporizer (ORV) with an intermediate vaporizer (IFV). The intermediate medium collects LNG cold energy and transmits it to various cold energy utilization projects. LNG boil-off gas is also used for triple power generation, with waste heat from the power generation used in the LNG vaporizer. This opens up a new path for energy conservation, consumption reduction, and revenue generation at the receiving station. However, this patent focuses on energy-saving processes for LNG receiving stations and does not address downstream cold-use applications, thus failing to provide a reference for cold energy utilization in downstream industries.

[0004] Chinese patent application CN117804094A discloses a freeze-drying process system and method using LNG cold energy based on CO2 refrigerant. The system utilizes LNG cold energy to pre-freeze materials in the freeze-drying chamber and to capture water vapor in a cold trap. It is equipped with an electric compression refrigeration system coupled with an LNG cold energy recovery and utilization system for supplemental cooling to improve process operation flexibility, enabling a single process system capable of freeze-drying all types of materials. This patent only uses LNG cold energy for freeze-drying and does not integrate it with other cold-using industries. The process uses an expansion valve and compressor to provide lower cold energy for the freeze dryer, but does not recover waste heat from the compressor outlet for use in the freeze-drying chamber, resulting in energy waste. Furthermore, the outlet NG also needs to be heated, requiring numerous heat exchange devices and complex process control. Summary of the Invention

[0005] Based on the rapid development of the current domestic LNG industry, cold chain logistics industry, pre-prepared meals, central kitchens and other food processing industries, and combined with the current research status of LNG cold energy technology, the present invention proposes a cold industrial park system process based on LNG cold energy, which uses LNG cold energy for ice making, cold storage, quick freezing and freeze drying, etc., to achieve efficient energy utilization and industrial integration.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a cold industrial park system based on LNG cold energy, comprising an LNG cold energy recovery module, an ice making module, a cold storage module, a freeze-drying and quick-freezing module, and a heat pump module;

[0007] The LNG cold energy recovery module includes an LNG heat exchanger and a circulating refrigerant heater. The outlet of the circulating refrigerant heater is connected to the LNG heat exchanger. The outlet of the LNG heat exchanger is divided into three paths, which pass through the ice making module, the cold storage module, and the freeze drying and quick freezing module respectively and are connected to the inlet of the circulating refrigerant heater.

[0008] The heat pump module includes a heat pump compressor, a heat pump expansion valve, and an evaporator connected in sequence, and the evaporator is connected to the water pool of the ice making module. The two ends of the circulating refrigerant heater are respectively connected to the heat pump compressor and the heat pump expansion valve.

[0009] As a further improvement of the present invention, the heat pump module also includes a condenser, which is arranged between the heat pump compressor and the heat pump expansion valve to participate in the high-temperature refrigerant circulation of the heat pump module, and a high-temperature refrigerant circulation pipeline is formed between the condenser and the circulating refrigerant heater.

[0010] As a further improvement of the present invention, the ice making module includes a first circulating refrigerant circulation barrel, a first circulating refrigerant heat exchanger, an ice making circulation barrel, an ice maker, and a water pool connected in sequence;

[0011] The circulating refrigerant at the outlet of the LNG heat exchanger passes through the first circulating refrigerant circulation barrel, enters the first circulating refrigerant heat exchanger, exchanges heat with the ice-making refrigerant in the ice-making circulation barrel, and then flows to the circulating refrigerant heater; the ice-making circulation barrel and the ice-making machine constitute an ice-making refrigerant circulation pipeline.

[0012] As a further improvement of the present invention, the ice making module includes a first circulating refrigerant circulating barrel, a first circulating refrigerant heat exchanger, an ice making pool, and a water pool connected in sequence;

[0013] The circulating refrigerant at the outlet of the LNG heat exchanger passes through the first circulating refrigerant circulation barrel and enters the first circulating refrigerant heat exchanger to directly supply cold to the ice making pool.

[0014] As a further improvement of the present invention, the cold storage module includes a second circulating refrigerant circulation barrel, a second circulating refrigerant heat exchanger, a cold storage circulation barrel, and a cold storage, which are connected in sequence;

[0015] The circulating refrigerant at the outlet of the LNG heat exchanger passes through the second circulating refrigerant circulation barrel, enters the second circulating refrigerant heat exchanger, exchanges heat with the cold storage refrigerant in the cold storage circulation barrel, and then flows to the circulating refrigerant heater; the cold storage circulation barrel and the cold storage constitute a cold storage refrigerant circulation pipeline.

[0016] As a further improvement of the present invention, the freeze-drying and quick-freezing module includes a third-cycle refrigerant circulation barrel, a third-cycle refrigerant heat exchanger, a low-temperature expansion valve, and a low-temperature circulation barrel, which are connected in sequence, and the low-temperature circulation barrel is respectively connected to the quick freezer, the cold trap, and the low-temperature compressor, and the low-temperature compressor is connected to the three-way valve, the freeze-drying bin, and the third-cycle refrigerant heat exchanger in sequence.

[0017] On the other hand, the present invention also provides the following technical solutions:

[0018] A cooling method for a cold industrial park based on LNG cold energy is characterized by utilizing the above-mentioned cold industrial park system based on LNG cold energy to perform the following steps, including:

[0019] LNG from the receiving station enters the LNG heat exchanger, exchanges heat with the gas circulating refrigerant, and heats up to gasify into NG, and then returns to the receiving station. At the same time, the gas circulating refrigerant cools down and liquefies into low-temperature liquid circulating refrigerant, which is then divided into three routes to the ice making module, cold storage module, freeze drying and quick freezing module for cooling. The low-temperature gas circulating refrigerant from the ice making module, cold storage module, freeze drying and quick freezing module enters the circulating refrigerant heater, exchanges heat with the high-temperature refrigerant, and heats up before entering the LNG heat exchanger. The high-temperature refrigerant cools down after heat exchange, enters the condenser, and exchanges heat with the high-temperature refrigerant at the outlet of the heat pump compressor, and heats up, completing the cycle.

[0020] The circulating refrigerant in the ice-making module passes through the first circulating refrigerant circulation barrel and enters the first circulating refrigerant heat exchanger to exchange heat with the gaseous ice-making refrigerant coming out of the ice-making circulation barrel and vaporize it. It returns to the first circulating refrigerant circulation barrel and then leaves the ice-making module. The ice-making refrigerant is liquefied after heat exchange and enters the return ice-making circulation barrel. It is then transported to the ice-making machine to release cold energy, and then returns to the ice-making circulation barrel after vaporization and temperature increase.

[0021] The circulating refrigerant in the cold storage module passes through the second circulating refrigerant circulation barrel (12), enters the second circulating refrigerant heat exchanger, exchanges heat with the gaseous cold storage refrigerant coming out of the cold storage circulation barrel, and then returns to the second circulating refrigerant circulation barrel to leave the cold storage module; the cold storage refrigerant is liquefied after heat exchange, enters the return cold storage circulation barrel, and is then transported to the cold storage to release cold energy, and then returns to the cold storage circulation barrel after gasification and temperature increase;

[0022] The circulating refrigerant in the freeze-drying and quick-freezing module passes through the third-circulation refrigerant circulation barrel and then enters the third-circulation refrigerant heat exchanger to exchange heat with the gaseous low-temperature refrigerant for vaporization. It returns to the third-circulation refrigerant circulation barrel and then leaves the freeze-drying and quick-freezing module. The low-temperature refrigerant is liquefied through heat exchange and then throttled and expanded by the low-temperature expansion valve for cooling before entering the low-temperature circulation barrel. It is then divided into two routes, entering the quick freezer and cold trap for cooling respectively, and then returns to the low-temperature circulation barrel after vaporization. After being pressurized and heated by the low-temperature compressor, it enters the freeze-drying bin to provide heat energy for the material, and then enters the third-circulation refrigerant heat exchanger to complete the cycle.

[0023] As a further improvement of the present invention, the high-temperature refrigerant in the heat pump module is liquefied and cooled through heat exchange in a circulating refrigerant heater or a condenser, and then throttled and expanded into a gas-liquid mixture through a heat pump expansion valve, enters the evaporator, exchanges heat with the water in the water pool and heats up, and then enters the heat pump compressor to complete the cycle, so that the cold energy generated in the heat pump module is used for pre-cooling the water in the water pool, thereby accelerating the ice making speed of the ice maker.

[0024] As a further improvement of the present invention, the condenser in the heat pump module is cancelled according to actual conditions, and the high-temperature refrigerant at the outlet of the heat pump compressor is directly fed into the circulating refrigerant heater to reheat the circulating refrigerant.

[0025] As a further improvement of the present invention, when the temperature of the cold storage is 7-12°C higher than the circulating refrigerant, the second circulating refrigerant heat exchanger and the cold storage circulating barrel are cancelled, and the circulating refrigerant is directly supplied to the cold storage.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. High energy efficiency. The heat pump heats the circulating refrigerant and generates cold energy for pre-cooling the pool, achieving efficient energy utilization and improving ice-making efficiency. At the same time, the low-temperature compressor pressurizes the low-temperature refrigerant and generates heat energy for melting ice crystals in the freeze-drying chamber, reducing the use of freeze-drying chamber heating equipment and compressor condensers, achieving efficient energy utilization.

[0028] 2. Strong universality and high operational flexibility. Equipped with an expansion valve and a low-temperature compressor, it can meet the cooling needs of users at different temperatures and flexibly adjust the gasification pressure and temperature of the low-temperature refrigerant.

[0029] 3. Expand the scope of cold energy utilization and achieve greater economic benefits. Providing feasible cold energy utilization technology for LNG cold energy to be used in different cold industries within the cold industry park will facilitate industrial collaboration and create greater benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to illustrate the technical solution more clearly, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] Figure 1 A schematic diagram of a process for realizing a cold industrial park system based on LNG cold energy provided by an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of a process in which circulating refrigerant directly enters a cold storage according to an embodiment of the present invention;

[0033] Figure 3A schematic diagram of a process for making ice using brine according to an embodiment of the present invention;

[0034] As shown in the figure: 1 is an LNG heat exchanger, 2 is a heat pump compressor, 3 is a condenser, 4 is a heat pump expansion valve, 5 is an evaporator, 6 is a circulating refrigerant heater, 7 is a first-circulation refrigerant circulation barrel, 8 is a first-circulation refrigerant heat exchanger, 9 is an ice-making circulation barrel, 10 is an ice-making machine, 11 is a water tank, 12 is a second-circulation refrigerant circulation barrel, 13 is a second-circulation refrigerant heat exchanger, 14 is a cold storage circulation barrel, 15 is a cold storage, 16 is a third-circulation refrigerant circulation barrel, 17 is a third-circulation refrigerant heat exchanger, 18 is a low-temperature expansion valve, 19 is a low-temperature circulation barrel, 20 is a low-temperature compressor, 21 is a three-way valve, 22 is a quick freezer, 23 is a freeze-drying bin, and 24 is a cold trap. DETAILED DESCRIPTION

[0035] In order to enable a clear and complete understanding of the technical solution, the present invention is further described in conjunction with the embodiments and drawings. Obviously, the described embodiments are only some embodiments of the present invention, and all other embodiments obtained by technical personnel in the relevant field without making creative work are within the scope of protection of the present invention.

[0036] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0037] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0038] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0039] The embodiment of the present invention discloses a cold industrial park system based on LNG cold energy, which uses LNG cold energy for ice making, cold storage, quick freezing and freeze drying, etc., to achieve efficient energy utilization and industrial integration. Figure 1-3 As shown, the system includes LNG cold energy recovery module, ice making module, cold storage module, freeze drying and quick freezing module, and heat pump module;

[0040] It should be noted that the present invention does not impose any limitation on the circulating refrigerant and other refrigerants. The technicians can set it according to the actual use requirements. Generally speaking, the circulating refrigerant of the present invention includes but is not limited to all phase change refrigerants such as ammonia, CO2, Freon, light hydrocarbons, etc.; Freon refrigerants include but are not limited to any one of R23, R507, and R410a, and light hydrocarbon refrigerants include but are not limited to any one of ethane, propane, ethylene, and propylene or a mixture thereof.

[0041] Specifically, the LNG cold energy recovery module includes an LNG heat exchanger 1 and a circulating refrigerant heater 6. The outlet of the circulating refrigerant heater 6 is connected to the LNG heat exchanger 1. The outlet of the LNG heat exchanger 1 is divided into three paths, which pass through the ice making module, the cold storage module, and the freeze drying and quick freezing module respectively and are connected to the inlet of the circulating refrigerant heater 6.

[0042] The heat pump module includes a heat pump compressor 2, a heat pump expansion valve 4, and an evaporator 5 connected in sequence, and the evaporator 5 is connected to the water pool 11 of the ice making module. The two ends of the circulating refrigerant heater 6 are respectively connected to the heat pump compressor 2 and the heat pump expansion valve 4.

[0043] In some embodiments, the heat pump module also includes a condenser 3, which is arranged between the heat pump compressor 2 and the heat pump expansion valve 4 to participate in the high-temperature refrigerant circulation of the heat pump module, and a high-temperature refrigerant circulation pipeline is formed between the condenser 3 and the circulating refrigerant heater 6.

[0044] In this embodiment, the circulating refrigerant is CO2, the LNG flow rate is 180t / h, the temperature is -150 to -160°C, and the pressure is 9.2MPa;

[0045] LNG at -160 to -150°C from the receiving station enters LNG heat exchanger 1 and exchanges heat with gaseous CO2 at a flow rate of 270 to 300 t / h, a temperature of 20 to 55°C, and a pressure of 1.2 to 1.4 MPa, raising its temperature to 0 to 5°C before returning to the receiving station. The gaseous CO2 is then cooled by heat exchange and liquefied into liquid CO2 at -40 to -30°C, which is then distributed in three routes to the ice making module, cold storage module, and freeze drying and quick freezing module for cooling.

[0046] The CO2 at -25 to -10℃ coming out of the ice making module, cold storage module, freeze drying and quick freezing module enters the circulating refrigerant heater 6 and exchanges heat with the 60℃ circulating hot water to raise the temperature to 20 to 55℃ before entering the LNG heat exchanger 1; the circulating hot water is cooled to 30 to 40℃ and then enters the condenser 3 and exchanges heat with the 80 to 90℃ high-temperature refrigerant at the outlet of the heat pump compressor 2 to complete the cycle.

[0047] In some implementations, the condenser 3 in the heat pump module can be eliminated according to actual conditions, and the high-temperature refrigerant at the outlet of the heat pump compressor 2 is directly fed into the circulating refrigerant heater 6 to reheat the circulating refrigerant.

[0048] That is to say, the CO2 at -25 to -10℃ coming out of the ice making module, cold storage module, freeze drying and quick freezing module enters the circulating refrigerant heater 6 and exchanges heat with the high-temperature refrigerant at 80 to 90℃ at the outlet of the heat pump compressor 2 to raise the temperature to 20 to 55℃ and enters the LNG heat exchanger 1; the high-temperature refrigerant is liquefied by heat exchange and cooled to 30 to 35℃ liquid, and then throttled and expanded to 0 to 5℃ gas-liquid mixture through the heat pump expansion valve 4, enters the evaporator 5, exchanges heat with water, and raises the temperature to 10 to 20℃, and enters the heat pump compressor 2 to complete the cycle.

[0049] In the above embodiment, the heat pump module generates cold energy for pre-cooling the water in the water pool 11, which can speed up the ice making speed of the ice maker 10, achieve efficient energy utilization and improve ice making efficiency.

[0050] In order to better understand the role of the ice-making module in the system, in an optional embodiment, the ice-making module includes a first circulating refrigerant circulation barrel 7, a first circulating refrigerant heat exchanger 8, an ice-making circulating barrel 9, an ice-making machine 10, and a water tank 11 connected in sequence; the circulating refrigerant at the outlet of the LNG heat exchanger 1 passes through the first circulating refrigerant circulation barrel 7 and enters the first circulating refrigerant heat exchanger 8 to exchange heat with the ice-making refrigerant in the ice-making circulating barrel 9, and then flows to the circulating refrigerant heater 6; the ice-making circulating barrel 9 and the ice-making refrigerant circulation pipeline constitute an ice-making refrigerant circulation pipeline.

[0051] Furthermore, the ice maker 10 is not limited to ice makers but is also applicable to ice pools. When an ice pool is used, the ice circulation barrel 9 can be eliminated. To better understand the use of an ice pool, an optional implementation is provided. The ice making module includes a first circulating refrigerant circulation barrel 7, a first circulating refrigerant heat exchanger 8, an ice pool, and a water pool 11, which are sequentially connected. The circulating refrigerant from the outlet of the LNG heat exchanger 1 passes through the first circulating refrigerant circulation barrel 7 and enters the first circulating refrigerant heat exchanger 8, directly supplying cooling to the ice pool.

[0052] In an optional implementation, the liquid CO2 at -40 to -30°C in the ice-making module passes through the first circulating refrigerant circulation barrel 7 and enters the first circulating refrigerant heat exchanger 8 to exchange heat with the gaseous R507 at -10 to 0°C coming out of the ice-making circulation barrel 9 and vaporizes to -25 to -10°C, returns to the first circulating refrigerant circulation barrel 7 and leaves the ice-making module; the gaseous R507 is liquefied into a liquid at -20 to -15°C and then enters the return ice-making circulation barrel 9, and is then transported to the ice-making machine 10 to release cold energy, and returns to the ice-making circulation barrel 9 after vaporization and heating.

[0053] In some embodiments, the liquid CO2 at -40 to -30°C in the ice-making module passes through the first circulating refrigerant circulation barrel 7 and enters the first circulating refrigerant heat exchanger 8 to exchange heat with the -15 to -10°C calcium chloride aqueous solution coming out of the ice-making pool and vaporizes to -25 to -15°C, returns to the first circulating refrigerant circulation barrel 7, and then leaves the ice-making module; the calcium chloride aqueous solution is cooled to -22 to -17°C and then transported to the ice-making machine 10 to release cold energy, and then returns to the first circulating refrigerant heat exchanger 8 after heating.

[0054] In order to better understand the role of the cold storage module in the system, in an optional implementation, the cold storage module includes a second circulating refrigerant circulation barrel 12, a second circulating refrigerant heat exchanger 13, a cold storage circulation barrel 14, and a cold storage 15 connected in sequence; the circulating refrigerant at the outlet of the LNG heat exchanger 1 passes through the second circulating refrigerant circulation barrel 12 and enters the second circulating refrigerant heat exchanger 13 and the cold storage circulation barrel 14 for heat exchange with the cold storage refrigerant, and then flows to the circulating refrigerant heater 6; the cold storage circulation barrel 14 and the cold storage 15 constitute a cold storage refrigerant circulation pipeline.

[0055] In this embodiment, specific refrigerant parameters are used as an example: the liquid CO2 at -40 to -30°C in the cold storage module passes through the second circulating refrigerant circulation barrel 12 and enters the second circulating refrigerant heat exchanger 13 and exchanges heat with the gaseous CO2 at -23 to -20°C coming out of the cold storage circulation barrel 14 to be vaporized to -27 to -25°C, and then returns to the second circulating refrigerant circulation barrel 12 and leaves the cold storage module; the gaseous CO2 from the cold storage circulation barrel is liquefied by heat exchange and cooled to -30 to -25°C and then enters the return cold storage circulation barrel 14, and then is transported to the cold storage 15 to release cold energy, and returns to the cold storage circulation barrel 14 after vaporization and temperature increase.

[0056] In some implementations, when the cold storage temperature is more than 7°C higher than the circulating refrigerant, the second circulating refrigerant heat exchanger 13 and the cold storage circulating barrel 14 can be eliminated, and the circulating refrigerant can be supplied directly to the cold storage. In other words, the liquid CO2 at -40 to -30°C in the cold storage module enters the cold storage circulating barrel 14 and then enters the cold storage 15 to release cold energy. It vaporizes and heats up to -30 to -25°C before returning to the cold storage circulating barrel 14.

[0057] Furthermore, the cold storage 15 is not limited to cold storage, and is also applicable to cold storage in production workshop environments, hallways, air-conditioning systems, etc.

[0058] In order to better understand the role of the freeze-drying and quick-freezing module in the system, in an optional implementation, the freeze-drying and quick-freezing module includes a third-cycle refrigerant circulation barrel 16, a third-cycle refrigerant heat exchanger 17, a low-temperature expansion valve 18, and a low-temperature circulation barrel 19, which are connected in sequence, and the low-temperature circulation barrel 19 is respectively connected to the quick freezer 22, the cold trap 24, and the low-temperature compressor 20, and the low-temperature compressor 20 is connected to the three-way valve 21, the freeze-drying bin 23, and the third-cycle refrigerant heat exchanger 17 in sequence.

[0059] Furthermore, the heat energy of the high-temperature refrigerant at the outlet of the low-temperature compressor 20 is used to melt ice crystals in the freeze-drying chamber 23, achieving efficient energy utilization. When the freeze-drying chamber does not need to be heated or the heat demand is reduced, the flow rate can be adjusted through the three-way valve to ensure load balance.

[0060] Further explanation: the liquid CO2 at -40~-30℃ in the freeze-drying and quick-freezing module passes through the third circulating refrigerant circulation barrel 16 and enters the third circulating refrigerant heat exchanger 17 to exchange heat with the gaseous R23 at 1.2~1.4MPa and -20~-10℃ and gasify to -25~-20℃. It returns to the third circulating refrigerant circulation barrel 16 and leaves the freeze-drying and quick-freezing module; the gaseous R23 is liquefied by heat exchange and cooled to -25~-20℃ and then throttled and expanded by the low-temperature expansion valve 18. The gas-liquid mixture with a temperature of 0.4-0.5 MPa and -55--50°C enters the low-temperature circulation barrel 19, and then is divided into two paths, entering the quick freezer 22 and the cold trap 24 for cooling. After vaporization and heating to -35--30°C, it returns to the low-temperature circulation barrel 19, is pressurized and heated to 1.0-1.2 MPa and 35-50°C by the low-temperature compressor 20, and then enters the freeze-drying chamber 23 to provide heat energy for the material, and then enters the third circulation refrigerant heat exchanger 17 to complete the cycle.

[0061] Obviously, the above embodiments are only used to illustrate the system structure of the present invention and are not intended to limit the scope of protection of the present invention. Without departing from the concept of the present invention, those skilled in the art can adjust the above system structure so that the present invention can be applied to more specific application scenarios.

[0062] In order to better understand the above system structure, the cooling method of the system is described below in conjunction with an embodiment, but it is not intended to limit the technical solution of the embodiment of the present invention. Specifically:

[0063] An embodiment of the present invention provides a cooling method for a cold industrial park based on LNG cold energy, which uses a cold industrial park system based on LNG cold energy according to one or more of the above embodiments to perform the following steps:

[0064] LNG from the receiving station enters the LNG heat exchanger 1 and exchanges heat with the gas circulating refrigerant to increase its temperature and gasify into NG. It then returns to the receiving station. At the same time, the gas circulating refrigerant is cooled and liquefied into low-temperature liquid circulating refrigerant. It is then divided into three routes to supply cooling to the ice making module, cold storage module, freeze drying and quick freezing module.

[0065] The low-temperature gas circulating refrigerant coming out of the ice making module, cold storage module, freeze drying and quick freezing module enters the circulating refrigerant heater 6 to exchange heat with the high-temperature refrigerant and heat up before entering the LNG heat exchanger 1;

[0066] After the high-temperature refrigerant cools down through heat exchange, it enters the condenser 3 and exchanges heat with the high-temperature refrigerant at the outlet of the heat pump compressor 2 to heat up, completing the cycle.

[0067] The circulating refrigerant in the ice-making module passes through the first circulating refrigerant circulation barrel 7 and enters the first circulating refrigerant heat exchanger 8 to exchange heat with the gaseous ice-making refrigerant coming out of the ice-making circulation barrel 9 and vaporize it. It returns to the first circulating refrigerant circulation barrel 7 and then leaves the ice-making module. The ice-making refrigerant is liquefied after heat exchange and enters the return ice-making circulation barrel 9. It is then transported to the ice-making machine 10 to release cold energy, and then returns to the ice-making circulation barrel 9 after vaporization and temperature increase.

[0068] The circulating refrigerant in the cold storage module passes through the second circulating refrigerant circulation barrel 12 and enters the second circulating refrigerant heat exchanger 13 to exchange heat with the gaseous cold storage refrigerant coming out of the cold storage circulation barrel 14 and gasify it. It returns to the second circulating refrigerant circulation barrel 12 and then leaves the cold storage module. The cold storage refrigerant is liquefied after heat exchange and enters the return cold storage circulation barrel 14. It is then transported to the cold storage 15 to release cold energy, and returns to the cold storage circulation barrel 14 after gasification and temperature increase.

[0069] The circulating refrigerant in the freeze-drying and quick-freezing module passes through the third circulating refrigerant circulation barrel 16 and enters the third circulating refrigerant heat exchanger 17 to exchange heat with the gaseous low-temperature refrigerant for vaporization, and then returns to the third circulating refrigerant circulation barrel 16 and leaves the freeze-drying and quick-freezing module; the low-temperature refrigerant is liquefied after heat exchange and throttling expansion and cooling through the low-temperature expansion valve 18, and then enters the low-temperature circulation barrel 19, and then splits into two paths, entering the quick freezer 22 and the cold trap 24 for cooling respectively, and returns to the low-temperature circulation barrel 19 after vaporization, and enters the freeze-drying bin 23 after pressurization and heating by the low-temperature compressor 20 to provide heat energy for the material, and then enters the third circulating refrigerant heat exchanger 17 to complete the cycle.

[0070] Based on the above embodiment, the high-temperature refrigerant in the heat pump module is liquefied and cooled through the circulating refrigerant heater 6 or the condenser 3 through heat exchange, and then throttled and expanded to a gas-liquid mixture through the heat pump expansion valve 4 to enter the evaporator 5. After heat exchange with the water in the water pool 11 and heating, it enters the heat pump compressor 2 to complete the cycle, so that the cold energy generated in the heat pump module is used for pre-cooling the water in the water pool 11, thereby accelerating the ice making speed of the ice maker 10.

[0071] In an optional embodiment, the condenser 3 in the heat pump module is cancelled according to actual conditions, and the high-temperature refrigerant at the outlet of the heat pump compressor 2 is directly fed into the circulating refrigerant heater 6 to reheat the circulating refrigerant.

[0072] In an optional embodiment, when the temperature of the cold storage is 7-12° C. higher than the circulating refrigerant, the second circulating refrigerant heat exchanger 13 and the cold storage circulating barrel 14 are removed, and the circulating refrigerant is directly supplied to the cold storage.

[0073] In the above method embodiment, LNG cold energy is used for users such as ice making, cold storage, quick freezing, and freeze drying, achieving efficient energy utilization and industrial integration. Specific refrigerant parameter examples and the connections and processes in each method step have been described in the above system structure embodiment. Although the control of each module is described in the above order, those skilled in the art will understand that some control steps of some modules can be operated independently, and modules can be combined and operated through some control steps. It is not necessary to run all steps to achieve the corresponding technical effects, and the details will not be repeated here.

[0074] Through the above steps, the heat pump module of this embodiment generates cold energy while heating the circulating refrigerant, which is used for pre-cooling the water pool, thereby achieving efficient energy utilization and improving ice making efficiency; at the same time, the low-temperature compressor generates heat energy while pressurizing the low-temperature refrigerant, which is used for the melting of ice crystals of materials in the freeze-drying chamber, reducing the use of freeze-drying chamber heating equipment and compressor condensers, and achieving efficient energy utilization.

[0075] In order to achieve the effect of this embodiment, different steps do not have to be executed in this order. They can be executed simultaneously (in parallel) or in a reverse order. These simple changes are within the scope of protection of the present invention.

[0076] The above disclosure is only one or more preferred embodiments of the present invention, which is used to help understand the inventive concept of the technical solution, and does not limit the present invention in other forms. Technicians in the relevant field may make other equivalent or customary replacement solutions based on the features defined by the present invention, which still fall within the scope of the present invention.

Claims

1. A cold industrial park system based on LNG cold energy, characterized in that: Including LNG cold energy recovery module, ice making module, cold storage module, freeze drying and quick freezing module, heat pump module; The LNG cold energy recovery module includes an LNG heat exchanger and a circulating refrigerant heater. The outlet of the circulating refrigerant heater is connected to the LNG heat exchanger. The outlet of the LNG heat exchanger is divided into three routes, which pass through the ice making module, cold storage module, freeze drying and quick freezing module respectively and then connect to the inlet of the circulating refrigerant heater. The ice-making module includes a first-cycle refrigerant circulation barrel, a first-cycle refrigerant heat exchanger, an ice-making circulation barrel, an ice-making machine, and a water pool, which are connected in sequence. The circulating refrigerant from the LNG heat exchanger passes through the first-cycle refrigerant circulation barrel and enters the first-cycle refrigerant heat exchanger to exchange heat with the ice-making refrigerant in the ice-making circulation barrel, then flows to the circulating refrigerant heater to directly supply cold air to the ice-making pool. The ice-making circulation barrel and the ice-making mechanism form an ice-making refrigerant circulation pipeline; The heat pump module includes a heat pump compressor, a heat pump expansion valve, and an evaporator connected in sequence, and the evaporator is connected to the water pool of the ice making module. The two ends of the circulating refrigerant heater are respectively connected to the heat pump compressor and the heat pump expansion valve; The heat pump module also includes a condenser, which is arranged between the heat pump compressor and the heat pump expansion valve to participate in the high-temperature refrigerant circulation of the heat pump module, and a high-temperature refrigerant circulation pipeline is formed between the condenser and the circulating refrigerant heater; The freeze-drying and quick-freezing module includes a third-cycle refrigerant circulation barrel, a third-cycle refrigerant heat exchanger, a low-temperature expansion valve, and a low-temperature circulation barrel, which are connected in sequence. The low-temperature circulation barrel is respectively connected to the quick freezer, the cold trap, and the low-temperature compressor. The low-temperature compressor is connected to the three-way valve, the freeze-drying chamber, and the third-cycle refrigerant heat exchanger in sequence. The heat energy of the high-temperature refrigerant at the outlet of the low-temperature compressor is used to melt ice crystals in the freeze-drying chamber. When the freeze-drying chamber does not need to be heated or the heat demand is reduced, the flow rate can be adjusted through the three-way valve to ensure load balance. The cold storage module includes a second cycle refrigerant circulation barrel, a second cycle refrigerant heat exchanger, a cold storage circulation barrel, and a cold storage, which are sequentially connected; The circulating refrigerant at the outlet of the LNG heat exchanger passes through the second circulating refrigerant circulation barrel and enters the second circulating refrigerant heat exchanger to exchange heat with the cold storage refrigerant in the cold storage circulation barrel, and then flows to the circulating refrigerant heater; the cold storage circulation barrel and the cold storage constitute the cold storage refrigerant circulation pipeline; The following steps are also included: The LNG from the receiving station enters the LNG heat exchanger and exchanges heat with the gas circulating refrigerant to increase its temperature and gasify it into NG, and then returns to the receiving station. At the same time, the gas circulating refrigerant is cooled and liquefied into low-temperature liquid circulating refrigerant, and then divided into three routes to the ice making module, cold storage module, freeze drying and quick freezing module for cooling; the low-temperature gas circulating refrigerant coming out of the ice making module, cold storage module, freeze drying and quick freezing module enters the circulating refrigerant heater and exchanges heat with the high-temperature refrigerant to increase its temperature and enter the LNG heat exchanger; the high-temperature refrigerant is cooled by heat exchange and enters the condenser to exchange heat with the high-temperature refrigerant at the outlet of the heat pump compressor to increase its temperature, completing the cycle.

2. A cooling method for a cold industrial park based on LNG cold energy, characterized in that: The following steps are performed using a cold industrial park system based on LNG cold energy as claimed in claim 1, including: The circulating refrigerant in the ice-making module passes through the first circulating refrigerant circulation barrel and enters the first circulating refrigerant heat exchanger to exchange heat with the gaseous ice-making refrigerant coming out of the ice-making circulation barrel and vaporize it. It returns to the first circulating refrigerant circulation barrel and then leaves the ice-making module. The ice-making refrigerant is liquefied after heat exchange and enters the return ice-making circulation barrel. It is then transported to the ice-making machine to release cold energy, and then returns to the ice-making circulation barrel after vaporization and temperature increase. The circulating refrigerant in the cold storage module passes through the second circulating refrigerant circulation barrel and then enters the second circulating refrigerant heat exchanger to exchange heat with the gaseous cold storage refrigerant coming out of the cold storage circulation barrel and vaporize it. It then returns to the second circulating refrigerant circulation barrel and leaves the cold storage module. The cold storage refrigerant is liquefied after heat exchange and enters the return cold storage circulation barrel, and then is transported to the cold storage to release cold energy. After vaporization and temperature increase, it returns to the cold storage circulation barrel. The circulating refrigerant in the freeze-drying and quick-freezing module passes through the third-circulation refrigerant circulation barrel and then enters the third-circulation refrigerant heat exchanger to exchange heat with the gaseous low-temperature refrigerant for vaporization. It returns to the third-circulation refrigerant circulation barrel and then leaves the freeze-drying and quick-freezing module. The low-temperature refrigerant is liquefied through heat exchange and then throttled and expanded by the low-temperature expansion valve for cooling before entering the low-temperature circulation barrel. It is then divided into two routes, entering the quick freezer and cold trap for cooling respectively, and then returns to the low-temperature circulation barrel after vaporization. After being pressurized and heated by the low-temperature compressor, it enters the freeze-drying bin to provide heat energy for the material, and then enters the third-circulation refrigerant heat exchanger to complete the cycle.

3. A cooling method for a cold industrial park based on LNG cold energy according to claim 2, characterized in that: The high-temperature refrigerant in the heat pump module is liquefied and cooled by the circulating refrigerant heater or condenser through heat exchange, and then expanded into a gas-liquid mixture through the heat pump expansion valve and enters the evaporator. After heat exchange with the water in the pool and heating up, it enters the heat pump compressor to complete the cycle, so that the cold energy generated in the heat pump module is used to pre-cool the water in the pool and speed up the ice making speed of the ice maker.

4. A cooling method for a cold industrial park based on LNG cold energy according to claim 2, characterized in that: The condenser in the heat pump module is cancelled according to actual conditions, and the high-temperature refrigerant at the outlet of the heat pump compressor is directly fed into the circulating refrigerant heater to reheat the circulating refrigerant.

5. A cooling method for a cold industrial park based on LNG cold energy according to claim 2, characterized in that: When the temperature of the cold storage is 7~12℃ higher than the circulating refrigerant, the second circulating refrigerant heat exchanger and the cold storage circulating barrel are cancelled, and the circulating refrigerant is directly supplied to the cold storage.

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