CN-122014998-A - Flow adaptive type multi-temperature energy storage system and method based on LNG cold energy recovery

CN122014998ACN 122014998 ACN122014998 ACN 122014998ACN-122014998-A

Abstract

The invention discloses a flow adaptive type multi-temperature energy storage system and method based on LNG cold energy recovery. The system comprises an LNG gasification module, a cold energy recovery and storage module and an electric compression refrigeration module. The LNG gasification module adopts a gasification mode of combining a multistage heat exchanger and a gasifier group to realize efficient gasification and cold energy release of LNG, the cold energy recovery and energy storage system takes an energy storage module as a core and forms a cold energy storage and utilization channel with a refrigeration house to break through space-time limitation of cold energy utilization, and the voltage shrinkage refrigeration module and the cold energy recovery and storage module cooperatively operate to realize a cold supplementing function in a valley period. According to the invention, through the collaborative design of the energy storage module and the electric compression refrigeration, the LNG flow fluctuation is flexibly adapted, the running cost is reduced by using low-price electricity compensation in the electricity consumption low-valley period, and meanwhile, the multi-temperature-level accurate energy storage is realized through the pressure regulating valve, so that the system has the advantages of high cold energy utilization rate, good running economy, strong suitability and the like, and is suitable for multi-scene cold energy resource utilization of LNG receiving stations, satellite stations and the like.

Inventors

XU WENDONG
LIU SHENGGUANG
SUN XICHENG
Cai Huangming
HU HANLIANG
HUANG CHUNYUE

Assignees

华南理工大学
广东广大新能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260304

Claims (10)

1. The flow adaptive type multi-temperature-position energy storage system based on LNG cold energy recovery is characterized by comprising an LNG gasification module, a cold energy recovery storage module and an electric compression refrigeration module; The LNG gasification module comprises a first gasifier (2), an LNG storage tank (3), an LNG pump (4), a first heat exchanger (7), a second heat exchanger (9) and a second gasifier (12), wherein the input end of the first gasifier (2) is connected with the tube side input end of the first heat exchanger (7) in parallel, and is communicated with the output end of the LNG pump (4) after being connected in parallel, the tube side output end of the first heat exchanger (7) is communicated with the tube side input end of the second heat exchanger (9), and the tube side output end of the second heat exchanger (9) is communicated with the input end of the second gasifier (12); The voltage reduction refrigeration module comprises a fourth heat exchanger (22), a throttle valve (24), a gas-liquid separator (26), a compressor (28) and a condenser (31), wherein the output end of the gas-liquid separator (26), the compressor (28), the condenser (31), the throttle valve (24) and the tube side of the fourth heat exchanger (22) are sequentially connected with the input end of the gas-liquid separator (26) to form a loop; The cold energy recovery storage module comprises a third heat exchanger (16), a refrigerant storage tank (25), a refrigerant pump (32), an energy storage module (35), a refrigeration house (38) and a first pressure regulating valve (39), wherein the shell side output end of the second heat exchanger (9), the shell side output end of the third heat exchanger (16) and the shell side output end of the fourth heat exchanger (22) are connected in parallel and flow into the input end of the refrigerant storage tank (25), the output end of the refrigerant storage tank (25) is respectively connected with the input end of the energy storage module (35) and the input end of the refrigeration house (38) through the refrigerant pump (32), and the output end of the energy storage module (35) and the output end of the refrigeration house (38) are converged and are respectively communicated with the shell side input end of the second heat exchanger (9), the shell side input end of the third heat exchanger (16) and the shell side input end of the fourth heat exchanger (22) through the first pressure regulating valve (39).
2. The flow-adaptive multi-temperature energy storage system based on LNG cold energy recovery of claim 1 is characterized in that a first regulating valve (1) and a second regulating valve (6) are respectively arranged between a parallel branch where the first vaporizer (2) and the first heat exchanger (7) are located and the LNG storage tank (3) and used for regulating and distributing LNG flow, and a first stop valve (5) is arranged on the parallel branch where the first heat exchanger (7) is located and used for controlling the on-off of an LNG cold energy recovery process.
3. The flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery according to claim 1, further comprising a pressure regulator (13) and a metering system (14), wherein the output end of the first gasifier (2) and the output end of the second gasifier (12) are connected with the pressure regulator (13) and the metering system (14).
4. The flow adaptive multi-temperature energy storage system based on LNG cold energy recovery according to claim 1, wherein the circulating refrigerant between the first heat exchanger (7) and the third heat exchanger (16) is ethane.
5. The flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery according to claim 1, wherein heat exchange media in the second heat exchanger (9), the third heat exchanger (16) and the fourth heat exchanger (22) are the same refrigerant.
6. The flow adaptive multi-temperature energy storage system based on LNG cold energy recovery according to claim 1, wherein a fifth regulating valve (19) is arranged between the first pressure regulating valve (39) and the fourth heat exchanger (22) and is used for starting electric compression cold supplement when LNG flows are low.
7. The flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery according to claim 1, wherein a seventh regulating valve (33) is arranged on a branch between the refrigerant storage tank (25) and the energy storage module (35), and an eighth regulating valve (37) is arranged between the branch between the refrigerant storage tank (25) and the refrigeration house (38) for realizing seamless switching of working conditions.
8. The flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery according to claim 1, wherein the energy storage module (35) comprises an energy storage unit (41), the energy storage unit (41) is a three-tube energy storage unit and comprises an outer tube, a middle tube and an inner tube which are coaxially arranged, a phase change cold storage material (42) is filled in the middle tube, and a heat exchange medium flows through the inner tube and the outer tube as a double cold source.
9. The flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery according to any one of claims 1 to 8, wherein a second pressure regulating valve (40) is arranged between a tube side output end of the third heat exchanger (16) and a shell side input end of the first heat exchanger (7), and the first pressure regulating valve (39) and the second pressure regulating valve (40) are used for changing the temperature of the energy storage according to the temperature requirements of the energy storage module by respectively changing the operating pressure of the secondary refrigerant and the primary refrigerant ethane so as to change the gas-liquid phase saturation temperature of the refrigerant, so that the temperature of the energy storage is changed.
10. A flow adaptive multi-temperature energy storage method based on LNG cold energy recovery, characterized in that the system according to any one of claims 1-9 is adopted, the method comprising the steps of: S1, LNG in an LNG storage tank (3) enters a first heat exchanger (7) through an LNG pump (4) to exchange heat with primary refrigerants, and enters a second heat exchanger (9) to be further heated after gasification and temperature rise; S2, exchanging heat between the primary refrigerant in the first heat exchanger (7) and LNG to obtain cold energy, then entering a third heat exchanger (16) to exchange heat with the secondary refrigerant, and heating the primary refrigerant to return to the first heat exchanger (7), exchanging heat between the LNG and the secondary refrigerant in the second heat exchanger (9), and cooling the secondary refrigerant; S3, the cold energy recovery storage module comprises two working conditions of LNG flow in a peak period and a valley period, when the LNG flow is in the peak period, the electric compression refrigeration module is not required to be started, the secondary refrigerant is cooled by heat exchange and then is collected into the refrigerant storage tank (25), then is conveyed to the energy storage module (35) and the refrigeration house (38) to release cold energy, heat is circularly exchanged after temperature rise, when the LNG flow is in the valley period, a refrigerant channel of the refrigeration house (38) is cut off, the electric compression refrigeration module is started, the LNG flow is exactly matched with the electricity consumption valley period, the compressor (28) is driven to operate by electricity consumption valley period low-price electricity, the low-temperature refrigerant obtained by compression refrigeration and the secondary refrigerant are subjected to heat exchange in the fourth heat exchanger (22), and the secondary refrigerant is collected into the refrigerant storage tank (25) after heat exchange and temperature reduction, and is conveyed to the energy storage module (35) to be circularly supplemented with cold.

Description

Flow adaptive type multi-temperature energy storage system and method based on LNG cold energy recovery Technical Field The invention relates to the technical field of Liquefied Natural Gas (LNG) cold energy recycling, in particular to a flow adaptive type multi-temperature energy storage system and method based on LNG cold energy recycling. Background Liquefied Natural Gas (LNG) is used as clean and efficient energy, a large amount of high-grade cold energy can be released in the gasification process, and recycling of the LNG is an important direction of energy conservation and emission reduction in the energy field. Along with the continuous improvement of the quantity and the receiving capacity of LNG receiving stations in China, the demands of LNG cold energy recycling are increasingly urgent. At present, the LNG cold energy recovery technology is mainly applied to the scenes such as power generation, liquefied air separation, low-temperature refrigeration houses and the like, and the core is that LNG gasification cold energy is transmitted to an energy storage or energy utilization unit through refrigerant circulation, so that the gradient utilization of energy sources is realized, and the cold energy waste and the environmental influence are reduced. The prior LNG cold energy recycling technology still faces a plurality of realistic bottlenecks in practical application, the fixed layout of an LNG receiving station and the period of cold energy release are centralized, the utilization of the guided cold energy is difficult to break through space-time constraint, cross-regional and time-sharing flexible allocation cannot be realized, meanwhile, the system lacks effective self-adaptive adjustment capability for fluctuation of LNG output flow, surplus cold energy causes resource waste in peak period, the continuity of cold energy consumption is affected in valley period due to insufficient cold energy supply, in addition, the LNG cold energy has the characteristic of wide temperature area, the problems of overlarge heat exchange temperature difference, insufficient cold energy recovery and the like commonly exist in the cold energy recycling process of the prior art, the utilization rate of the guided cold energy is always at a lower level, and the resource value of the LNG cold energy cannot be fully exerted. An improved scheme of partially focusing LNG cold energy recovery and embedded energy storage module appears in the related technical field, an LNG cold energy recovery and storage and transportation system disclosed in patent CN220669154U realizes cold energy long-distance transportation through a phase-change storage and transportation sled, solves the problem of cold energy space dislocation, is not provided with a cold supplementing module, cannot guarantee cold energy supply in a low-valley period of flow, is not provided with multi-temperature regulation and control and surplus cold energy storage designs, is insufficient in cold energy utilization rate and operation stability, and an LNG cold energy recovery and ice making system disclosed in Chinese patent publication CN117927858A is used for optimizing an ice making process through cold storage tank storage cold energy, is limited to cold energy in a station and used at the periphery, cannot be used in a geographic way, lacks a flow fluctuation adaptation and cold supplementing mechanism, and is insufficient in cold energy recovery in a wide temperature region. Disclosure of Invention In order to overcome at least one of the defects and shortcomings of the prior art, the invention provides a flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery, and aims to provide an LNG cold energy recovery and utilization scheme which is strong in working condition adaptability, high in cold energy utilization rate, excellent in running economy and capable of breaking through space-time constraint. The invention forms a cooperative mechanism of 'cold energy cascade recovery-cold energy storage-dynamic cold compensation' by constructing a two-stage refrigerant circulating system and combining an independent energy storage module and a voltage cold compensation device, optimizes an operation mode, designs a differential regulation strategy aiming at the peak and the valley of LNG flow, and simultaneously realizes multi-temperature energy storage by matching with a first pressure regulating valve, thereby solving the problems of mismatching in cold space and time, poor adaptability of flow fluctuation and single scene coverage in the traditional technology, ensuring continuous and stable system cold energy supply, and remarkably improving comprehensive energy utilization efficiency and operation economic benefit. In order to achieve the purpose of the invention, the flow adaptive type multi-temperature energy storage system based on LNG cold energy recovery comprises an LNG gasification module, a cold energy recovery s