CN118687091B

CN118687091B - LNG-RG and LAES coupling system and coupling method

Info

Publication number: CN118687091B
Application number: CN202410752033.5A
Authority: CN
Inventors: 施政
Original assignee: RUIHAN ENERGY TECHNOLOGY CO LTD
Current assignee: RUIHAN ENERGY TECHNOLOGY CO LTD
Priority date: 2024-06-12
Filing date: 2024-06-12
Publication date: 2025-10-17
Anticipated expiration: 2044-06-12
Also published as: CN118687091A; WO2025256465A1

Abstract

The present invention discloses a coupling system and coupling method of LNG-RG and LAES, relating to the field of large-scale energy storage technology; the coupling system comprises: an LAES subsystem, an LNG-RG subsystem and a coupled cold exchange subsystem; in the charging condition of the LAES subsystem, ambient air is sequentially compressed by a normal temperature compressor and the compression heat energy is output to a heat storage tank for storage, then cooled to a cryogenic temperature by the coupled cold exchange subsystem, then compressed and heated to a shallow cold temperature by a first-stage low-temperature compressor, and then cooled to a cryogenic temperature by the coupled cold exchange subsystem to enter the next-stage low-temperature compressor; wherein the cryogenic temperature is the pressurized outlet temperature during the regasification process of liquefied natural gas, and the shallow cold temperature is the outlet temperature of the ambient air after the ambient air is cryogenically compressed. The present invention establishes a coupled cooling subsystem between the LAES subsystem and the LNG-RG subsystem to uniformly manage cold energy. Through a dual-temperature compression mode of room-temperature compression and multi-stage low-temperature compression, the high-quality cold energy of the LNG-RG subsystem is utilized to directly reduce the temperature of the ambient air before entering the low-temperature compressor to a cryogenic temperature, thereby reducing the power consumption of the LAES subsystem's air compression process and improving the charging and discharging efficiency of the entire LAES subsystem.

Description

LNG-RG and LAES coupling system and coupling method

Technical Field

The invention belongs to the technical field of large-scale energy storage, and particularly relates to a coupling system and a coupling method of LNG-RG and LAES.

Background

The principle of the Liquid air energy Storage (LAES, liquid AIR ENERGY Storage) is that low-cost valley electricity is utilized to absorb air in the environment and then cool the air until the air becomes Liquid for Storage, and the Liquid air is released and boosted and heated when electricity is used in a peak, and then enters an expander to perform work for power generation, so that valley electricity peak use is realized, and an important role can be played in grid peak regulation. However, the energy loss exists in the charging and discharging processes, and in order to supplement the lost energy, additional electric energy is generally consumed to supplement the energy, so that the cost is high.

In recent years, natural gas has been steadily increasing in specific gravity as clean energy in energy consumption, and particularly LNG has been widely used and paid attention to with improvement of natural gas liquefaction technology and reduction of LNG (Liquefied Natural Gas) transportation costs. The LNG receiving terminal usually relates to an LNG Re-Gasification (RG) process, a large amount of cold energy can be released in the process of changing LNG Re-heating into natural gas, and the coupling application of the LAES system and the LNG-RG system has great practical application significance and prospect.

At present, a plurality of coupling models are provided for LAES and LNG-RG by students and manufacturers at home and abroad, but the charge and discharge efficiency of the LAES system in the coupling models still needs to be improved. In particular, the prior art has the following disadvantages:

1. Only the coupling of the LAES charging working condition and the LNG-RG is considered in the existing model, but the fluctuation and intermittent operation are not necessarily predicted in many cases of the LNG-RG, so that the model is inconsistent with the actual situation, the theoretical effect of the coupling model is difficult to achieve, the maximum utilization of the LNG-RG cold energy is difficult to achieve, and the overall charge and discharge efficiency of the LAES is not high enough;

2. The existing model only couples the LAES traditional model with the LNG-RG, and does not have targeted optimization on the LAES side, so that the value of cold energy of the LNG-RG is not furthest mined, and the overall charge and discharge efficiency of the LAES is still improved.

Disclosure of Invention

Therefore, an object of the present invention is to provide a coupling system for LNG-RG and LAES, so as to reasonably utilize the wasted cold energy of LNG-RG to the greatest extent, and solve the problem of low charge-discharge efficiency of LAES system in the coupling model in the prior art.

In some illustrative embodiments, the LAES and LNG-RG coupling system includes a LAES subsystem, an LNG-RG subsystem, and a coupled chilled subsystem; the LAES subsystem comprises a heat storage tank, a normal temperature compressor, a multi-stage low temperature compressor unit consisting of at least 2 low temperature compressors, a low temperature expander, a liquid-air separator, a liquid air storage tank, a discharge low temperature pump and an expander, wherein the normal temperature compressors are sequentially connected; the system comprises a normal temperature compressor, a multi-stage low temperature compressor unit, a low temperature expander, a liquid-air separator and a liquid air storage tank which are sequentially connected, wherein the normal temperature compressor, the multi-stage low temperature compressor unit, the low temperature expander, the liquid-air separator and the liquid air storage tank form an ambient air liquefaction path for converting ambient air into liquid air; the coupled cooling exchanging subsystem at least supports the LNG-RG subsystem to output cold energy to the LAES subsystem and stores and releases the cold energy of the LNG-RG subsystem and the LAES subsystem, wherein the coupled cooling exchanging subsystem comprises a cryogenic tank for storing and releasing the cryogenic energy generated by the LNG-RG subsystem and the cryogenic energy generated by the discharge working condition of the LAES subsystem, the cold end temperature is a cryogenic temperature, the hot end temperature is a shallow cold temperature, the ambient air is sequentially compressed by the normal temperature compressor and outputs compressed heat energy to the heat storage tank for storage under the charging working condition of the LAES subsystem, the coupled cooling exchanging subsystem is cooled to the cryogenic temperature, the low temperature compressor is compressed and warmed to the shallow cold temperature by the first stage, the coupled cooling exchanging subsystem is cooled to the cryogenic temperature, the cryogenic temperature is the pressurized outlet temperature in the regasification process of the liquefied natural gas, and the cryogenic temperature is the ambient air outlet temperature after the ambient air is compressed at a low temperature.

In some optional embodiments, the LNG-RG subsystem further comprises a charging cryogenic pump, wherein the normal temperature compressor, the multi-stage cryogenic compressor unit, the charging cryogenic pump, the cryogenic expander, the liquid-air separator and the liquid air storage tank which are sequentially connected form the ambient air liquefaction path, and in the charging working condition of the LAES subsystem, ambient air is compressed by the multi-stage cryogenic compressor, then cooled to a cryogenic temperature by the coupling refrigeration subsystem to enter a complete liquefaction or supercritical state, then compressed to higher pressure by the charging cryogenic pump, then cooled to a cryogenic temperature by the coupling refrigeration subsystem and then enters the cryogenic expander.

In some alternative embodiments, the LNG-RG subsystem comprises a liquefied natural gas regasification path for converting liquefied natural gas into regasified natural gas, the coupled cryogenic heat exchange subsystem further comprises a cryogenic charge heat exchanger, a cryogenic discharge heat exchanger and a natural gas cryogenic heat exchanger, wherein the natural gas cryogenic heat exchanger is arranged on the liquefied natural gas regasification path of the LNG-RG subsystem, wherein the cryogenic charge heat exchanger is arranged on an ambient air liquefaction path of the LAES subsystem for cooling incoming and outgoing ambient air of each cryogenic compressor to cryogenic temperatures respectively, wherein the cryogenic discharge heat exchanger is arranged on the liquid air regasification path of the LAES subsystem between the discharge cryopump and the expander, and wherein the cryogenic charge heat exchanger, the cryogenic discharge heat exchanger, the hot end of the natural gas cryogenic heat exchanger and the cold end of the cryogenic tank are connected to the cold end of the cryogenic tank respectively.

In some alternative embodiments, the LNG-RG subsystem comprises a liquefied natural gas regasification path for converting liquefied natural gas into regasified natural gas, the coupled cryogenic heat exchange subsystem further comprises a plurality of cryogenic tanks, wherein each cryogenic tank is a solid packed bed and has cold storage and exchange functions, each cryogenic tank is arranged on an ambient air liquefaction path and a liquid air regasification path of the LAES subsystem at the same time, the ambient air liquefaction path and the liquid air regasification path are the same in path and have opposite air flow directions in the cryogenic tanks, the cryogenic tanks and the cryogenic compressors are arranged at intervals on the ambient air liquefaction path for cooling the ambient air entering and exiting each cryogenic compressor to a cryogenic temperature, the natural gas cryogenic heat exchangers are arranged on the liquefied natural gas regasification path of the LNG-RG subsystem, and the cryogenic heat exchangers are respectively connected with the cold end and the hot end of each cryogenic tank.

In some optional embodiments, the coupling and cooling subsystem further comprises a shallow cooling tank for storing and releasing shallow cooling energy generated by the LNG-RG subsystem and shallow cooling energy generated by the LAES subsystem under a discharging working condition, wherein a cold end temperature of the shallow cooling tank is the shallow cooling temperature, and a hot end temperature of the shallow cooling tank is the ambient temperature, and the coupling and cooling subsystem outputs the shallow cooling energy to the outside of the coupling system through the shallow cooling tank under any working condition of the LAES subsystem.

In some optional embodiments, the LAES subsystem further comprises an ultra-cold tank for storing and releasing ultra-cold energy generated when the LAES subsystem is in a discharging condition, wherein in a charging condition of the LAES subsystem, ambient air discharged by the multi-stage low-temperature compressor unit is cooled to a cryogenic temperature by the coupling cooling subsystem and then sequentially enters the hot end of the ultra-cold tank, the low-temperature expander and the liquid-air separator, and ultra-cold reflux air output by the liquid-air separator firstly enters the cold end of the ultra-cold tank;

The cold end temperature of the super-cooling tank is super-cooling temperature, the hot end temperature of the super-cooling tank is cryogenic temperature, and the super-cooling temperature is pressurized outlet temperature in the process of regasifying liquid air.

In some optional embodiments, the coupling system further comprises a return air compressor and a return air expander, wherein during the charging condition of the LAES subsystem, part of the return air flowing out of the hot end of the super-cooled tank is sequentially compressed and warmed by the return air compressor, cooled to a cryogenic temperature by the coupling cooling subsystem, expanded and cooled by the return air expander, and then is collected into the super-cooled return air output from the liquid-air separator.

In some alternative embodiments, the coupling system further comprises an external heat source providing external heat energy, and the thermal storage tank and the external heat source cooperate to provide compressed heat energy and external heat energy to the regasified air during discharge conditions of the LAES subsystem.

In some optional embodiments, the cryogenic tank of the coupled cooling subsystem is a solid packed bed, the heat exchange device of the coupled cooling subsystem is a heat exchanger, the solid packed bed exchanges cold energy with the heat exchanger through a heat exchange medium, or the cryogenic tank of the coupled cooling subsystem and the heat exchange device are integrated in a solid packed bed structure, and the ambient air exchanges cold energy with a cold accumulation medium in the solid packed bed through a pipe wall of a circulation pipeline of the ambient air.

In some optional embodiments, the cryogenic tank of the coupled cooling exchange subsystem comprises a hot-end heat-insulating container and a cold-end heat-insulating container, the heat exchange device of the coupled cooling exchange subsystem is a heat exchanger, the hot end and the cold end of the heat exchanger are respectively connected with the hot-end heat-insulating container and the cold-end heat-insulating container, the heat-insulating containers are filled with liquid heat exchange media, and cold energy storage and exchange between the two heat-insulating containers are realized through the liquid heat exchange media.

In some optional embodiments, the coupling system further comprises an air purifier arranged on an ambient air liquefaction path of the LAES subsystem and between the normal temperature compressor and the multi-stage low temperature compressor unit, wherein in a charging working condition of the LAES subsystem, the ambient air is compressed by the normal temperature compressor, then is recovered by the heat storage tank to compress heat energy, then enters the air purifier, is cooled to a cryogenic temperature by the coupling cooling subsystem after purification, enters the multi-stage low temperature compressor unit, and in a discharging working condition of the LAES subsystem, the regasified air output by the expander at least partially flows through the air purifier and is then discharged to the environment.

Another object of the present invention is to provide a coupling method of LAES and LNG-RG to solve the technical problems in the prior art.

In some illustrative embodiments, the coupling method of the LAES and the LNG-RG comprises the steps of converting ambient air into liquid air for storage under a charging working condition, wherein the process comprises the steps of compressing the ambient air at normal temperature, recovering compression heat energy generated by compression, reducing the temperature of the ambient air after normal-temperature compression to the ambient temperature, and obtaining the ambient air with target pressure through multi-stage low-temperature compression, wherein the cryogenic energy in a cryogenic tank is utilized to cool the temperature of the ambient air before and after each stage of low-temperature compression to a cryogenic temperature, the cryogenic energy in the cryogenic tank is from a liquefied natural gas regasification process and a liquid air regasification process, the cold end temperature of the cryogenic tank is the cryogenic temperature, the cryogenic temperature is the pressurized outlet temperature in the liquefied natural gas regasification process, and the hot end temperature of the cryogenic tank is the shallow cold temperature, and the shallow cold temperature is the ambient air outlet temperature after the low-temperature compression of the ambient air.

In some optional embodiments, the liquefaction phase transition temperature of the ambient air under the target pressure is higher than the cryogenic temperature, the process of cooling the ambient air before and after each stage of low-temperature compression to the cryogenic temperature by using the cryogenic energy in the cryogenic tank comprises the steps of cooling the ambient air after the last stage of low-temperature compression to the cryogenic temperature to obtain the liquid air with the target pressure, and the process of converting the ambient air into the liquid air for storage under the charging working condition, and the process of compressing the liquid air with the target pressure to the higher pressure and then performing low-temperature expansion.

In some alternative embodiments, the process of converting the ambient air into liquid air for storage during the charging condition further comprises cooling the ambient air to a shallow cooling temperature using the shallow cooling energy in the shallow cooling tank prior to cooling the ambient air to the cryogenic temperature using the cryogenic energy in the cryogenic tank, wherein the shallow cooling energy in the shallow cooling tank is from a liquefied natural gas regasification process and a liquid air regasification process.

In some alternative embodiments, the coupling method further comprises the step of converting the liquid air into the regasified air for heating expansion under the discharging condition, wherein the step of recovering the super-cold energy in the regasified air in the regasification process of the liquid air by using the super-cold tank, the step of converting the ambient air into the liquid air for storage under the charging condition, and the step of cooling the ambient air with the target pressure from the cryogenic temperature to the super-cold temperature, wherein the cold end temperature of the super-cold tank is the super-cold temperature, the hot end temperature of the super-cold tank is the cryogenic temperature, and the super-cold temperature is the pressurized outlet temperature in the regasification process of the liquid air.

In some optional embodiments, the process of converting the ambient air into liquid air for storage under the charging working condition further comprises the steps of performing low-temperature expansion on the ambient air with super-cooling temperature to generate liquid air and super-cooling reflux air, separating and discharging the super-cooling reflux air, recycling super-cooling energy in the super-cooling reflux air through the super-cooling tank to convert the super-cooling energy into reflux air with cryogenic temperature, compressing at least part of the reflux air with cryogenic temperature, cooling the part of the reflux air after compression and heating to cryogenic temperature by utilizing the cryogenic energy in the super-cooling tank, performing low-temperature expansion on the part of the reflux air after expansion and cooling, and then collecting the part of the reflux air into the super-cooling reflux air after separation and discharging.

In some optional embodiments, the process of converting the ambient air into liquid air for storage under the charging working condition further comprises the step of adsorbing carbon dioxide and water in the ambient air which is compressed at normal temperature and recovered by heat energy through an air purifier before the multi-stage low-temperature treatment, and the process of converting the ambient air into liquid air for storage under the charging working condition further comprises the step of introducing at least part of the regasified air after expansion work into the air purifier for desorption treatment of the carbon dioxide and the water.

Compared with the prior art, the invention has the following advantages:

the invention establishes a coupling cooling exchange subsystem between the LAES subsystem and the LNG-RG subsystem for unified management of cold energy, and directly reduces the temperature of ambient air before entering a low-temperature compressor to a cryogenic temperature by utilizing the high-grade cold energy of the LNG-RG subsystem through a double-temperature compression mode of normal-temperature compression and multi-stage low-temperature compression, thereby reducing the consumption power of the air compression process of the LAES subsystem and further improving the charge and discharge efficiency of the whole LAES subsystem.

Drawings

FIG. 1 is a schematic diagram of an exemplary configuration of a coupling system in accordance with an embodiment of the present invention;

FIG. 2 is an exemplary operating condition A of a coupling system according to an embodiment of the present invention;

FIG. 3 is an exemplary operating condition B of a first embodiment of a coupling system configuration in accordance with the present invention;

FIG. 4 is an exemplary operating condition C of a first embodiment of a coupling system configuration in accordance with the present invention;

FIG. 5 is a second example of the structure of a coupling system in an embodiment of the present invention;

FIG. 6 is an example of a second operating condition A of a coupling system configuration in an embodiment of the present invention;

FIG. 7 is an example of a second operating condition B of a coupling system configuration in an embodiment of the present invention;

FIG. 8 is an exemplary second operating condition C of the coupling system configuration in an embodiment of the present invention;

Fig. 9 is a schematic diagram of a charge-discharge flow of the LAES subsystem according to an embodiment of the present invention.

Reference numerals illustrate:

Natural gas cryogenic Heat exchanger HXNG-DC (Heat Exchanger Natural Gas-Deep Cold), natural gas Shallow Leng Huanre device HXNG-SC (Heat Exchanger Natural Gas-short Cold), normal temperature Compressor C1 (Compressor 1), first stage low temperature Compressor C2 (Compressor 2), second stage low temperature Compressor C3 (Compressor 3), charging low temperature pump CCP (Charging Cryogenic Pump), heat accumulating and charging Heat exchanger HXC-H (Heat Exchanger Charging-Heat), heat storage discharge Heat exchanger HXD-H (Heat Exchanger Discharging-Heat), shallow Cold charge Heat exchanger HXD-SC (Heat Exchanger Charging-Cold Cold), shallow Leng Fangdian Heat exchanger HXD-SC (Heat Exchanger Discharging-Cold Cold), first cryogenic charge Heat exchanger HXD-DC 1 (Heat Exchanger Charging-Deep Cold 1), Second cryogenic charging heat exchanger HXC-DC2 (Heat Exchanger Charging-Deep Cold 2), third cryogenic charging heat exchanger HXC-DC3 (Heat Exchanger Charging-Deep Cold 3), fourth cryogenic charging heat exchanger HXC-DC4 (Heat Exchanger Charging-Deep Cold 4), cryogenic discharging heat exchanger HXD-DC (Heat Exchanger Discharging-Deep Cold), ultra-Cold charging heat exchanger HXC-UC (Heat Exchanger Charging-Ultra Cold), Super Cold discharge heat exchanger HXD-UC (Heat Exchanger Discharging-Ultra Cold), low temperature expander CE (Cryogenic Expander), liquid-air separator LAS (Liquid Air Separator), liquid air storage tank LAD (Liquid Air Dewar), discharge low temperature pump DCP (Discharge Cryogenic Pump), heat storage tank HD (Heat Dewar), shallow cooling tank SCD (Shallow Cold Dewar), the cryogenic tank DCD (Deep Cold Dewar), a first cryogenic tank DCD1 (Deep Cold Dewar 1), a second cryogenic tank DCD2 (Deep Cold Dewar 2), a third cryogenic tank DCD3 (Deep Cold Dewar 3), an Ultra-Cold tank UCD (Ultra Cold Dewar), a return Air Compressor C-UCA (pressure-Ultra Cold Air), a return Air Expander E-UCA (expansion-Ultra Cold Air), Air purifier APU (Air Purification Unit), first Valve V1 (Valve 1), second Valve V2 (Valve 2), third Valve V3 (Valve 3), fourth Valve V4 (Valve 4), fifth Valve V5 (Valve 5), sixth Valve V6 (Valve 6), seventh Valve V7 (Valve 7), eighth Valve V8 (Valve 8), ninth Valve V9 (Valve 9), tenth Valve V10 (Valve 10), eleventh Valve V11 (Valve 11), Twelfth Valve V12 (Valve 12), thirteenth Valve V13 (Valve 13), fourteenth Valve V14 (Valve 14), fifteenth Valve V15 (Valve 15), sixteenth Valve V16 (Valve 16), seventeenth Valve V17 (Valve 17), eighteenth Valve V18 (Valve 18), nineteenth Valve V19 (Valve 19), twentieth Valve V20 (Valve 20), twentieth Valve V21 (Valve 21), twentieth Valve V22 (Valve 22), twenty-third Valve V23 (Valve 23), twenty-fourth Valve V24 (Valve 24), twenty-fifth Valve V25 (Valve 25);

Ambient Air (Air), first ambient Air (Air 1), second ambient Air (Air 2), third ambient Air (Air 3), fourth ambient Air (Air 4), fifth ambient Air (Air 5), sixth ambient Air (Air 6), seventh ambient Air (Air 7), eighth ambient Air (Air 8), ninth ambient Air (Air 9), tenth ambient Air (Air 10), eleventh ambient Air (Air 11)

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Unless otherwise defined herein, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. Unless explicitly described as such, the words "first," "second," and similar words used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are meant to encompass the elements or items listed thereafter and equivalents thereof without excluding other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. In order to keep the following description of the embodiments of the present invention clear and concise, well-known functions, known components, or detailed descriptions that are common general knowledge are omitted. Under the condition of no conflict, all the technical features in the embodiments of the present invention can be combined with each other, and the combined embodiments still belong to the protection scope of the present invention.

The embodiment of the invention discloses a coupling system for liquid air energy storage and liquefied natural gas regasification, which specifically comprises an LAES subsystem, an LNG-RG subsystem and a coupled cooling subsystem as shown in figures 1-8;

The LAES subsystem is used for converting the ambient air into liquid air for storage under a charging working condition and converting the liquid air into regasified air for expansion working under a discharging working condition, and concretely comprises a heat storage tank HD, a normal temperature compressor C1, a multi-stage low temperature compressor unit consisting of at least 2 low temperature compressors, a low temperature expander CE, a liquid-air separator LAS, a liquid air storage tank LAD, a discharging low temperature pump DCP and an expander E, wherein the normal temperature compressor C1 is sequentially connected in series. The device comprises a normal temperature compressor C1, a multi-stage low temperature compressor unit formed by at least 2 low temperature compressors which are sequentially connected in series, a low temperature expander CE, a liquid-air separator LAS and a liquid air storage tank LAD, wherein the normal temperature compressor C1, the multi-stage low temperature compressor unit formed by at least 2 low temperature compressors which are sequentially connected in series, the low temperature expander CE, the liquid air separator LAS and the liquid air storage tank LAD form an ambient air liquefaction path under a charging working condition of the low temperature compressor unit, the ambient air is converted into liquid air for storage, and the liquid air storage tank LAD, a discharge low temperature pump DCP and an expander E form a liquid air regasification path under a discharging working condition of the liquid air storage tank LAD, the discharge low temperature pump DCP and the expander E are sequentially connected in series, so that the liquid air is converted into regasified air for expansion work. The heat storage tank HD recovers compression heat energy from ambient air discharged from the normal temperature compressor C1 under a charging condition, and supplies the compression heat energy to regasified air under a discharging condition to heat and expand the regasified air.

The LNG-RG subsystem is used to convert Liquefied Natural Gas (LNG) to Natural Gas (NG), and specifically includes an LNG cryogenic pump (not shown) and an LNG regasification line (LNG to NG path in the illustration).

The coupled cooling exchanging subsystem comprises a cold accumulating device and a cooling exchanging device, wherein the cooling exchanging device is used for constructing a cooling exchanging system between the LAES subsystem and the LNG-RG subsystem, at least supporting the LNG-RG subsystem to output cold energy to the LAES subsystem, and storing and releasing the cold energy of the LNG-RG subsystem and the LAES subsystem, for example supporting the LNG-RG subsystem to output cold energy to the LAES subsystem, the LNG-RG subsystem to output cold energy to the cold accumulating device and the cold accumulating device to output cold energy to the LAES subsystem, and the cold accumulating device is used for storing and releasing the cold energy of the two subsystems. Wherein, in some embodiments, the cold storage device can have the functions of cold storage and cold exchange at the same time, and further can replace at least part of the cold exchange device.

Under the charging working condition of the LAES subsystem, the ambient air is compressed by the normal temperature compressor in sequence and outputs the compression heat energy to the heat storage tank, the coupled cooling exchanging subsystem utilizes the cryogenic energy generated by the LNG-RG subsystem and the cold energy stored under the discharging working condition of the LAES subsystem to cool to cryogenic temperature, the coupled cooling exchanging subsystem is compressed to cryogenic temperature to enter the next-stage low-temperature compressor for compression, the ambient air with target pressure is obtained after the ambient air is compressed by the last-stage low-temperature compressor, the coupled cooling exchanging subsystem is cooled to cryogenic temperature, and the converted liquid air is stored in the liquid-air separator to the liquid air storage tank after the cryogenic energy is expanded by the low-temperature expander.

The cryogenic temperature is the pressurized outlet temperature in the regasification process of the liquefied natural gas, and the cryogenic temperature is the ambient air outlet temperature after the ambient air is compressed at a low temperature.

Specifically, the pressurized outlet temperature during the regasification of lng refers to the temperature at the outlet location of the lng cryogenic pump during the regasification of lng, and the ambient air outlet temperature after the ambient air is cryogenically compressed refers to the temperature at the outlet location of each cryogenic compressor during the liquefaction of ambient air.

Further, the cold storage device comprises a cryogenic tank DCD in a cold exchange system of the access coupling cold exchange subsystem, and the cryogenic tank DCD is at least used for storing and releasing cryogenic energy generated by the LNG-RG subsystem. In some embodiments, the cryogenic tank may be further configured to store and release cryogenic energy generated during a discharging condition of the LAES subsystem, and further the coupled cooling exchange subsystem may utilize the cryogenic energy of the LNG-RG subsystem and the cryogenic energy stored during the discharging condition of the LAES subsystem to cool ambient air to a cryogenic temperature, where, when the cryogenic tank is involved in a cooling condition of the LAES subsystem or when the LNG-RG subsystem outputs the cryogenic energy to the cryogenic tank, the cold end temperature is the cryogenic temperature, that is, the temperature of the liquefied natural gas after being pressurized by the liquefied natural gas discharging cryopump before being heated by any heat source, is the lowest temperature of the cold energy outputted by the LNG-RG, and the hot end temperature is the shallow cooling temperature, that is, the ambient air outlet temperature after the ambient air is compressed at a low temperature.

In general, the temperature of the pressurized outlet in the process of regasification of the LNG will only exist on the LNG-RG subsystem side, after being subjected to cold exchange, the temperature of the LNG reaches the side of the coupled cold exchange subsystem (for example, cold storage equipment such as a cryogenic tank) and the temperature of the LNG at the side of the liquid air energy storage system will be affected by factors such as heat exchange efficiency and heat exchanger pinch point, and the pressurized outlet temperature in the process of regasification of the LNG cannot be kept continuously, which is common knowledge in the art, and for easy understanding, the cryogenic temperature of the LNG at the side of the coupled cold exchange subsystem (for example, cold storage equipment such as a cryogenic tank) and the LNG at the side of the liquid air energy storage system is set as the pressurized outlet temperature in the process of regasification of the LNG; it should be noted, however, that in practical applications, the cryogenic temperature is slightly different from the pressurized outlet temperature during LNG regasification, and that the difference between the actual cryogenic temperature and the pressurized outlet temperature during LNG regasification depends on the specific implementation parameters, but such differences do not affect the coverage and protection of the present invention.

According to the invention, the coupling cooling exchange subsystem is established between the LAES subsystem and the LNG-RG subsystem, and the high-grade cold energy of the LNG-RG subsystem is utilized to directly reduce the temperature of the ambient air before entering the low-temperature compressor to the cryogenic temperature through the double-temperature compression mode of normal-temperature compression and multi-stage low-temperature compression, so that the power consumption of the air compression process of the LAES subsystem can be reduced, and the charge and discharge efficiency of the whole LAES subsystem can be further improved.

The multi-stage low-temperature compressor unit in the embodiment of the invention is composed of at least 2 low-temperature compressors which are sequentially connected in series, such as a two-stage low-temperature compressor unit, a three-stage low-temperature compressor unit, a four-stage low-temperature compressor unit and the like. The multistage low-temperature compressor unit is mainly used for gradually compressing the ambient air to the target pressure so as to collect the ambient air with the target volume, and therefore, the stage number of the multistage low-temperature compressor unit can be set according to the design requirement of the system.

It should be noted that as the ambient air is compressed to gradually increase its pressure, the present invention cools the ambient air to a cryogenic temperature, at which time the dew point of the ambient air may be already higher than the cryogenic temperature, thereby causing a potential risk of equipment loss for the cryogenic compressors of the next stage, so that the temperature of the ambient air before entering each stage of the cryogenic compressors needs to be controlled to be lower than the dew point temperature of the ambient air.

For a typical system design, the ambient air dew point may be higher than the cryogenic temperature, which occurs after the penultimate low temperature compression or during the final low temperature compression, and therefore the ambient air temperature prior to entering the final low temperature compressor must be controlled to be not lower than the ambient air dew point temperature. Preferably, the ambient air entering the final stage cryocompressor is at least 5 degrees above the dew point temperature.

On the other hand, in the multi-stage low-temperature compression process, the high-pressure ambient air cooled to the cryogenic temperature is possibly completely liquefied, and the low-temperature compressor cannot continue to be suitable for subsequent compression at the moment, so that the low-temperature pump can continue to complete subsequent compression, and the high-pressure liquid air with the target volume is collected.

Further, the LAES subsystem may further include a charge cryopump for further compressing air to a higher pressure in a liquid or supercritical state at cryogenic temperatures;

The normal temperature compressor, the multi-stage low temperature compressor unit, the charging low temperature pump, the low temperature expander, the liquid-air separator and the liquid air storage tank are connected in sequence to form the ambient air liquefaction path;

and in the charging working condition of the LAES subsystem, the ambient air is compressed by the multi-stage low-temperature compressor, cooled to the cryogenic temperature by the coupling cooling subsystem, enters a complete liquefaction or supercritical state, is compressed to the higher pressure required by design by the charging low-temperature pump, is cooled to the cryogenic temperature by the coupling cooling subsystem, and enters the low-temperature expander.

In some embodiments, the cold storage device of the coupled cold exchange subsystem of the present invention may further comprise a shallow cold tank SCD for storing and releasing at least the shallow cold energy generated by the LNG-RG subsystem. The cold end temperature of the shallow cooling tank is the hot end temperature of the deep cooling tank, and the hot end temperature of the shallow cooling tank is the ambient temperature.

In some embodiments, the temperatures of the hot end and the cold end of the cryogenic tank and the shallow cold tank are defined in the invention, and certain differences exist according to the practical working conditions and the practical design parameter selection. For example, the shallow cooling temperature defined by the invention is the temperature of the ambient air discharged by the low-temperature compressor, and the temperature of the ambient air discharged by the low-temperature compressors of different stages can slightly differ, depending on the actual working condition and the setting of the compression ratio of the low-temperature compressor. The invention sets the temperature of the hot end of the cryogenic tank, and is used for matching the temperature of the ambient air before and after the low-temperature compressor to the greatest extent, so that the heat exchange efficiency is improved. The existence of such differences, which are well known in the art, does not affect the scope or content of the present invention.

At this time, the cryogenic tank DCD and the shallow tank SCD in the coupled refrigeration subsystem may be used to sequentially and stepwise recover and release the cryogenic energy and the shallow cold energy generated by the LNG-RG subsystem (and/or the LAES subsystem).

In some embodiments, the shallow cooling tank SCD in the embodiments of the present invention may be also matched with the cryogenic tank DCD to recover the shallow cooling energy generated by regasifying the liquid air under the discharging condition of the LAES subsystem, and the cryogenic energy and the shallow cooling energy generated by regasifying the liquid air are released through the recovery of the cryogenic tank DCD and the shallow cooling tank SCD in sequential steps.

Furthermore, the coupling cooling exchange subsystem in the embodiment of the invention can pre-cool the ambient air which completes the compression heat recovery under the charging working condition of the LAES subsystem by utilizing the shallow cold energy generated by the LNG-RG subsystem and/or the shallow cold energy in the shallow cold tank, and cool the ambient air at the stage to the shallow cold temperature, and then cool the ambient air to the deep cold temperature, so that the consumption of the deep cold energy can be reduced, thereby reasonably utilizing the cold energy resource and reducing the consumption of the high-quality cold energy.

Further, the recovery of the shallow cold energy generated by the regasification of the liquid air from the discharge condition of the LAES subsystem is sufficient to pre-cool the ambient air to a shallow cold temperature under the charge condition of the LAES subsystem, so that the process does not consume the shallow cold energy from the LNG-RG subsystem basically, and the shallow cold energy in the shallow cold tank can be applied to the outside of the coupling system through the coupling and cooling subsystem under any condition of the LAES subsystem, thereby generating economic benefits. In addition, the shallow cooling energy of the two subsystems is recovered through the shallow cooling tank, so that the equipment cost is reduced.

In some embodiments, the LAES subsystem of the present invention may further include an ultra-cold tank UCD for storing and releasing the ultra-cold energy generated during the discharging operation of the LAES subsystem, wherein the ultra-cold tank UCD recovers the ultra-cold energy from the regasification of the liquid air during the discharging operation, and provides the ultra-cold energy for the ambient air after completing the multi-stage low-temperature compression and cooling to the cryogenic temperature during the charging operation, so that the temperature of the ambient air at the stage is cooled to the ultra-cold temperature, the ultra-cold temperature is the outlet temperature of the pressurizing pressure during the regasification of the liquid air, and the ultra-cold temperature is lower than the cryogenic temperature, so that the ambient air reaching the ultra-cold temperature is subjected to low-temperature expansion, and the liquefaction efficiency of the ambient air is improved.

The pressurized outlet temperature in the process of regasifying the liquid air refers to the outlet temperature of a low-temperature pump at a discharge point in the process of regasifying the liquid air.

Because the super cooling temperature of super cooling energy is lower than the pressurized outlet temperature in the regasification process of liquefied natural gas, the pressurized outlet temperature is more, and the pressurized outlet temperature cannot be provided by the LNG-RG subsystem, the cooling value is highest in the coupling system, and the liquefied efficiency of the ambient air can be effectively improved through the recovery and release of the super cooling tank UCD.

Specifically, under the charging condition of the LAES subsystem, after the ambient air is cooled to a cryogenic temperature through the low-temperature compression and coupling cooling subsystem of the last-stage low-temperature compressor, the ambient air enters the hot end of the super-cooling tank UCD, flows out of the cold end of the super-cooling tank UCD, sequentially enters the low-temperature expander CE and the liquid-air separator LAS, and the converted liquid air is stored in the liquid air storage tank LAD through the liquid-air separator LAS. The super-cold reflux air output by the liquid-air separator LAS firstly enters the cold end of the super-cold tank UCD and flows out from the hot end of the super-cold tank UCD, so that the recovery of super-cold energy in the super-cold reflux air is completed.

In some embodiments, the LAES subsystem of the present invention may further comprise a return air compressor C-UCA and a return air expander E-UCA, wherein at least a portion of the return air flowing from the hot end of the super-cooled tank UCD is compressed and warmed by the return air compressor C-UCA, cooled to cryogenic temperature by the coupled cooling subsystem, expanded and cooled by the return air expander E-UCA, and then is introduced into the super-cooled return air outputted from the liquid-air separator LAS and entering the cold end of the super-cooled tank UCD under the charging condition of the LAES subsystem, thereby supplementing super-cooled energy.

In some embodiments, the LAES subsystem according to the embodiments of the present invention may further comprise an air purifier APU disposed between the normal temperature compressor C1 and the multi-stage low temperature compressor unit for removing carbon dioxide and water from the ambient air entering the LAES subsystem, so that the ambient air without carbon dioxide and water is subjected to subsequent low temperature compression. Specifically, under the charging condition of the LAES subsystem, ambient air is compressed by the normal temperature compressor C1 and compressed heat energy is output to the heat storage tank HD, and then enters the air purifier APU, and after being purified, the ambient air is cooled to a cryogenic temperature by the coupled cooling subsystem and then enters the low temperature compressor unit.

The principle of the air purifier for removing carbon dioxide and water in the ambient air is that carbon dioxide and water in the ambient air are adsorbed by the molecular sieve, so that at least part of the regasified air output by the expander can be discharged to the environment after flowing through the air purifier under the discharge working condition of the LAES subsystem, and the desorption of the carbon dioxide and water in the air purifier is completed by utilizing the part of the ambient air, thereby achieving the circulating operation of the air purifier in the charge and discharge process.

In some embodiments, the coupling system of the embodiments of the present invention may further comprise an external heat source for providing external heat energy, wherein the external heat source is not limited to ambient air, seawater, or other ambient heat sources, solar energy, or industrial waste heat.

Under the discharging working condition of the liquid air subsystem, the heat storage tank HD and the external heat source can jointly provide compression heat energy and external heat energy for the regasified air to heat and expand.

Optionally, the expander E in the embodiment of the present invention may be a multi-stage expansion unit formed by a plurality of sequentially connected expanders, and the temperature of the regasified air entering each expander may be raised and expanded by using the compression heat energy and the external heat energy. Including but not limited to, the regasified air absorbing external heat energy provided by an external heat source prior to entering the preceding expander and absorbing compression heat energy provided by a thermal storage tank prior to entering the second expander, or the regasified air absorbing compression heat energy provided by a thermal storage tank prior to entering the first expander and absorbing external heat energy provided by an external heat source prior to entering the following expander

In some embodiments, the cold storage medium of the cold storage device of the coupled cold exchange subsystem in the embodiment of the invention can be a solid medium or a liquid medium, the cold exchange device can be a heat exchanger, and the heat exchanger is matched with the cold storage device to construct a cold exchange system of the coupled cold exchange subsystem, so that cold energy exchange among the cold storage device, the LAES subsystem and the LNG-RG subsystem is realized. The number and implementation positions of the heat exchangers can be determined by the design requirements of the system, and the selected heat exchange medium can be selected according to different temperature requirements, so that the invention is not limited to the above.

In one embodiment, the cold storage device of the coupled cooling exchange subsystem is a solid packed bed, the heat exchange device is a heat exchanger, and the heat exchanger constructs a cooling exchange system of the LAES subsystem, the LNG-RG subsystem and the solid packed bed, and the cooling exchange is realized through a heat exchange medium.

In another embodiment, the cold storage device of the coupled cooling exchange subsystem in the embodiment of the invention is a solid packed bed, and integrates a part of heat exchange device functions, and is connected to an ambient air liquefying path under a charging working condition and an ambient air regasification path under a discharging working condition of the LAES subsystem at the same time, at this time, cold storage medium in the solid packed bed can exchange cold energy with ambient air under the charging and discharging working conditions of the LAES subsystem through pipe walls directly. And the other part of heat exchange equipment is a heat exchanger, and the heat exchanger can realize cold energy exchange between the LNG-RG subsystem and the solid packed bed, so that cold energy exchange among the LNG-RG subsystem and the solid packed bed is realized.

In another embodiment, the cold storage device (such as a cryogenic tank) of the coupled cold exchange subsystem in the embodiment of the invention comprises 2 independent heat insulation containers which are respectively used as a hot end and a cold end of the cold storage device, wherein the heat exchange device is a heat exchanger, the hot end of the heat exchanger is connected with the hot end of the cold storage device, and the cold end of the heat exchanger is connected with the cold end of the cold storage device to form the cold exchange system. The heat-insulating container is filled with a liquid heat exchange medium (such as liquid propane) to store and exchange cold energy, and the heat exchanger adopts the same liquid heat exchange medium. When the cold storage device stores cold energy, the heat exchange medium flows into the cold end (the second heat insulation container) of the cold storage device from the hot end (the first heat insulation container) of the cold storage device through the heat exchanger and absorbs cold energy from the heat exchanger in the transferring process, and when the cold storage device releases cold energy, the heat exchange medium flows into the hot end (the first heat insulation container) of the cold storage device from the cold end (the second heat insulation container) of the cold storage device through the heat exchanger and outputs cold energy through the heat exchanger in the transferring process.

In order to facilitate those skilled in the art to quickly understand the different collocation structures of the coupling and cooling subsystem, the present invention discloses a preferred embodiment of 2 coupling systems with different structures for different structures of the coupling and cooling subsystem, where it should be understood that the specific coupling system disclosed in the embodiment of the present invention is only used to quickly understand the different construction structures, and should not limit the practical protection scope of the present invention.

As shown in fig. 1, the embodiment of the invention discloses a coupling system for liquid air energy storage and liquefied natural gas regasification, which comprises an LAES subsystem, an LNG-RG subsystem and a coupling refrigeration subsystem;

the LAES subsystem comprises a heat storage tank HD, an ultra-cold tank UCD, a normal temperature compressor C1, a heat storage charging heat exchanger HXC-H, an air purifier APU, a secondary low temperature compressor unit consisting of 2 low temperature compressors (C2 and C3) which are sequentially connected in series, a charging low temperature pump CCP, an ultra-cold charging heat exchanger HXC-UC, a low temperature expander CE, a liquid-air separator LAS, a liquid air storage tank LAD, a discharging low temperature pump DCP, an ultra-cold discharging heat exchanger HXD-UC, a heat storage discharging heat exchanger HXD-H and an expansion unit (a first expansion machine E1, a second expansion machine E2, a third expansion machine E3 and a fourth expansion machine E4), a return air compressor C-UCA and a return air expansion machine E-UCA. The heat storage tank HD, the heat storage charging heat exchanger HXC-H and the heat storage discharging heat exchanger HXD-H are respectively connected at the hot ends through a first valve V1, the cold ends are respectively connected through a second valve V2, a specific heat exchange loop can be controlled by the first valve V1 and the second valve V2, the super-cooling tank UCD, the super-cooling charging heat exchanger HXC-UC and the super-cooling discharging heat exchanger HXD-UC are respectively connected at the hot ends through a third valve V3, the cold ends are respectively connected through a fourth valve V4, and the specific heat exchange loop can be controlled by the third valve V3 and the fourth valve V4. Wherein, liquid air storage tank LAD is connected through tenth valve V10 between liquid air separator LAS and the discharge cryopump DCP. The heat exchanger HXD2 is arranged between the first expander E1 and the second expander E2, the heat exchanger HXD3 is arranged between the second expander E2 and the third expander E3, the heat exchanger HXD4 is arranged between the third expander E3 and the fourth expander E4, and the heat exchanger HXD2, the heat exchanger HXD2 and the heat exchanger HXD2 acquire environmental heat from environmental heat sources.

An LNG-RG subsystem includes a liquefied natural gas cryopump and a liquefied natural gas regasification line.

The coupled cooling subsystem comprises a shallow cooling tank SCD, a cryogenic tank DCD, a shallow cooling charging heat exchanger HXC-SC, a shallow Leng Fangdian heat exchanger HXD-SC, a first cryogenic charging heat exchanger HXC-DC1, a second cryogenic charging heat exchanger HXC-DC2, a third cryogenic charging heat exchanger HXC-DC3, a fourth cryogenic charging heat exchanger HXC-DC4, a cryogenic discharging heat exchanger HXD-DC, a natural gas cryogenic heat exchanger HXNG-DC and a natural gas shallow Leng Huanre device HXNG-SC.

The shallow-cold charge heat exchanger HXC-SC, the shallow Leng Fangdian heat exchanger HXD-SC, the first cryogenic charge heat exchanger HXC-DC1, the second cryogenic charge heat exchanger HXC-DC2, the third cryogenic charge heat exchanger HXC-DC3, the fourth cryogenic charge heat exchanger HXC-DC4 and the cryogenic discharge heat exchanger in the LAES subsystem are coupled, so that the charging path of the LAES subsystem sequentially comprises a normal temperature compressor C1, a heat accumulating charge heat exchanger HXC-H, an air purifier APU, the shallow-cold charge heat exchanger HXC-SC, the first cryogenic charge heat exchanger HXC-DC1, a first-stage low temperature compressor HXC 2, the second cryogenic charge heat exchanger HXC-DC2, the second-stage low temperature compressor C3, the third cryogenic charge heat exchanger HXC-DC3, a charge low temperature pump CCP, the fourth cryogenic charge heat exchanger HXC-DC4, an ultra-cold charge heat exchanger HXC-UC, a liquid air separator LAS and a liquid air separator LAD; the discharging path of the LAES subsystem sequentially comprises a liquid air storage tank LAD, a discharging cryogenic pump DCP, an ultra-cold discharging heat exchanger HXD-UC, a deep-cold discharging heat exchanger HXD-DC, a shallow Leng Fangdian heat exchanger HXD-SC, a heat accumulating discharging heat exchanger HXD-H, a first expander E1, a second environmental heat exchanger HXD2, a second expander E2, a third environmental heat exchanger HXD3, a third expander E3, a fourth environmental heat exchanger HXD4 and a fourth expander E4.

The natural gas cryogenic heat exchanger HXNG-DC and the natural gas shallow Leng Huanre device HXNG-SC in the coupled cold exchange subsystem are coupled in the LNG-RG subsystem, so that the natural gas cryogenic heat exchanger HXNG-DC and the natural gas shallow Leng Huanre device HXNG-SC are sequentially arranged on the liquefied natural gas regasification pipeline along the liquefied natural gas regasification direction.

The hot ends of the shallow cooling tank SCD, the shallow cooling charging heat exchanger HXC-SC, the shallow Leng Fangdian heat exchanger HXD-SC and the natural gas shallow Leng Huanre device HXNG-SC are respectively connected through a fifth valve V5, the cold ends are respectively connected through a sixth valve V6, and a specific cooling circuit can be controlled by the fifth valve V5 and the sixth valve V6. The hot ends of the cryogenic tank DCD, the first cryogenic charging heat exchanger HXC-DC1, the second cryogenic charging heat exchanger HXC-DC2, the third cryogenic charging heat exchanger HXC-DC3, the fourth cryogenic charging heat exchanger HXC-DC4, the cryogenic discharging heat exchanger HXD-DC and the natural gas cryogenic heat exchanger HXNG-DC are respectively connected through a seventh valve V7, the cold ends are respectively connected through an eighth valve V8, and a specific cold exchange loop can be controlled by the seventh valve V7 and the eighth valve V8.

The super-cold reflux air led out from a gas phase outlet of a liquid-air separator LAS in the LAES subsystem sequentially enters an super-cold charging heat exchanger HXC-UC, a first cryogenic charging heat exchanger HXC-DC1 and a shallow cooling charging heat exchanger HXC-SC, and then returns to an inlet of a normal-temperature compressor C1. A ninth valve V9 is arranged on an ultra-cold reflux air pipeline between the liquid-air separator LAS and the ultra-cold charging heat exchanger HXC-UC, and a path of reflux air led out by the ninth valve V9 sequentially enters the reflux air compressor C-UCA, the first cryogenic charging heat exchanger HXC-DC1 and the reflux air expander E-UCA and returns to an inlet of the ultra-cold reflux air of the ultra-cold charging heat exchanger HXC-UC.

As shown in fig. 2, under the charging condition of the LAES subsystem, the LNG-RG subsystem is operated, a heat exchange loop is formed between the heat storage tank HD and the heat storage charging heat exchanger HXC-H, a cooling loop is formed between the shallow cooling tank SCD, the natural gas shallow Leng Huanre unit HXNG-SC, and the shallow cooling charging heat exchanger HXC-SC, and a cooling loop is formed between the cryogenic tank DCD, the natural gas cryogenic heat exchanger HXNG-DC, the first cryogenic charging heat exchanger HXC-DC1, the second cryogenic charging heat exchanger HXC-DC2, the third cryogenic charging heat exchanger HXC-DC3, and the fourth cryogenic charging heat exchanger HXC-DC 4.

At this time, the ambient AIR AIR sequentially enters a normal temperature compressor C1, a heat storage charging heat exchanger HXC-H, an AIR purifier APU, a shallow cold charging heat exchanger HXC-SC, a first cryogenic charging heat exchanger HXC-DC1, a first stage low temperature compressor C2, a second cryogenic charging heat exchanger HXC-DC2, a second stage low temperature compressor C3, a third cryogenic charging heat exchanger HXC-DC3, a charging low temperature pump CCP, a fourth cryogenic charging heat exchanger HXC-DC4, an ultra-cold charging heat exchanger HXC-UC, a low temperature expander CE, a liquid AIR separator LAS and a liquid AIR storage tank LAD, and the ultra-cold return AIR discharged from the liquid AIR separator LAS sequentially enters the ultra-cold charging heat exchanger HXC-UC, the first cryogenic charging heat exchanger HXC-DC1, the shallow cold charging heat exchanger HXC-SC and the return AIR returned to the inlet of the compressor C1, wherein part of the return AIR discharged from the ultra-cold charging heat exchanger HXC-UC sequentially enters the return AIR compressor C-UCC, the first cryogenic charging heat exchanger HXC-UC, and the ultra-cold return AIR from the ultra-cold charging heat exchanger UCC-UCC.

As shown in fig. 3, under the standing condition of the LAES subsystem, the LNG-RG subsystem operates, a cooling circuit is formed between the shallow cooling tank SCD and the natural gas shallow Leng Huanre device HXNG-SC, and a cooling circuit is formed between the cryogenic tank DCD and the natural gas cryogenic heat exchanger HXNG-DC.

At this time, the cryogenic energy and the shallow cooling energy of the LNG-RG subsystem are respectively output to the cryogenic tank DCD and the shallow cooling tank SCD.

As shown in fig. 4, under the discharging working condition of the LAES subsystem, the LNG-RG subsystem is operated, a heat exchange loop is formed between the heat storage tank HD and the heat storage discharging heat exchanger HXD-H, a cooling loop is formed between the shallow cooling tank SCD, the natural gas shallow Leng Huanre device HXNG-SC and the shallow Leng Fangdian heat exchanger HXD-SC, a cooling loop is formed between the cryogenic tank DCD, the natural gas cryogenic heat exchanger HXNG-DC and the cryogenic discharging heat exchanger HXD-DC, and a cooling loop is formed between the super cooling tank UCD and the super cooling discharging heat exchanger HXD-UC.

At this time, the liquid air in the liquid air storage tank LAD is pressurized by a discharge cryopump DCP, and then sequentially enters an ultra-cold discharge heat exchanger HXD-UC, a deep-cold discharge heat exchanger HXD-DC, a shallow Leng Fangdian heat exchanger HXD-SC, a heat storage discharge heat exchanger HXD-H, a first expander E1, a second environmental heat energy heat exchanger HXD2, a second expander E2, a third environmental heat energy heat exchanger HXD3, a third expander E3, a fourth environmental heat energy heat exchanger HXD4 and a fourth expander E4.

As shown in fig. 5, the embodiment of the invention discloses a coupling system for liquid air energy storage and liquefied natural gas regasification, which comprises an LAES subsystem, an LNG-RG subsystem and a coupling cooling subsystem, wherein the heat exchange equipment of the LAES subsystem has heat storage and heat exchange functions at the same time, and the cold storage equipment in the LAES subsystem and the coupling cooling subsystem has cold storage and cooling functions at the same time, in particular:

the LAES subsystem comprises a normal temperature compressor C1, a heat storage tank HD, an air purifier APU, a first-stage low-temperature compressor C2, a second-stage low-temperature compressor C3, an ultra-cold tank UCD, a low-temperature expander CE, a liquid-air separator LAS, a liquid air storage tank LAD, a discharge low-temperature pump DCP and an expander E.

An LNG-RG subsystem includes a liquefied natural gas regasification line.

The coupled cooling subsystem comprises a shallow cooling tank SCD, a first cryogenic tank DCD1, a second cryogenic tank DCD2, a third cryogenic tank DCD3, a natural gas cryogenic heat exchanger HXNG-DC and a natural gas shallow Leng Huanre device HXNG-SC.

The shallow cooling tank SCD, the first cryogenic tank DCD1, the second cryogenic tank DCD2 and the third cryogenic tank DCD3 in the coupled refrigeration subsystem are coupled in the LAES subsystem, so that a charging path of the LAES subsystem sequentially comprises a normal temperature compressor C1, an eleventh valve V11, a heat storage tank HD, a twelfth valve V12, an air purifier APU, a thirteenth valve V13, a shallow cooling tank SCD, a first cryogenic tank DCD1, a fourteenth valve V14, a first stage low temperature compressor C2, a fifteenth valve V15, a second cryogenic tank DCD2, a sixteenth valve V16, a second stage low temperature compressor C3, a seventeenth valve V17, a third cryogenic tank DCD3, an ultra-cold tank UCD, an eighteenth valve V18, a low temperature expander CE, a liquid air separator LAS 11, a nineteenth valve V19 and a liquid air storage tank LAD, and a discharging path of the LAES subsystem sequentially comprises a liquid air storage tank LAD, a nineteenth valve V19, an ultra-cold tank DCP V18, a seventeenth valve V12, a seventeenth valve V14, a seventeenth valve V3, a third cryogenic tank DCD, a seventeenth valve V12 and a seventeenth valve D. Wherein, the charge path and partial path of the discharge path of the LAES subsystem are multiplexed, but the air flows in opposite directions.

The hot ends of the shallow cooling tank SCD and the natural gas shallow Leng Huanre device HXNG-SC are respectively connected, the cold ends are respectively connected, the hot ends of the first cryogenic tank DCD1, the second cryogenic tank DCD2, the third cryogenic tank DCD3 and the natural gas cryogenic heat exchanger HXNG-DC are respectively connected through a twenty-second valve V22 and a twenty-third valve V23, the cold ends are respectively connected through a twenty-fourth valve V24 and a twenty-fifth valve V25, and a specific cold exchange loop can be controlled through the twenty-second valve V22, the twenty-third valve V23, the twenty-fourth valve V24 and the twenty-fifth valve V25.

The super-cold reflux air led out from the gas phase outlet of the liquid-air separator in the LAES subsystem sequentially enters a twentieth valve V20, a super-cold tank UCD, a twenty-first valve V21, a natural gas cryogenic heat exchanger HXNG-DC and a natural gas shallow Leng Huanre device HXNG-SC, and then returns to the inlet of the normal-temperature compressor C1. One path of return air is led out from the pipeline of the super-cold return air flowing out of the super-cold tank LAD through a twenty-first valve V21, sequentially enters a return air compressor C-UCA, a natural gas cryogenic heat exchanger HXNG-DC and a return air expander E-UCA, and then returns to the inlet of the super-cold return air of the super-cold tank UCD from a twentieth valve V20.

As shown in fig. 6, during the charging operation of the LAES subsystem, the LNG-RG subsystem is operated, and a cooling loop is formed between the shallow cooling tank SCD and the natural gas shallow Leng Huanre unit HXNG-SC, and a cooling loop is formed between the first cryogenic tank DCD1, the second cryogenic tank DCD2, the third cryogenic tank DCD3, and the natural gas cryogenic heat exchanger HXNG-DC.

At this time, the ambient AIR sequentially enters the normal temperature compressor C1, the heat accumulator HD, the AIR purifier APU, the shallow cooling tank SCD, the first cryogenic tank DCD1, the first stage low temperature compressor C2, the second cryogenic tank DCD2, the second stage low temperature compressor C3, the third cryogenic tank DCD3, the super cooling tank UCD, the low temperature expander CE, the liquid-AIR separator LAS and the liquid AIR storage tank LAD, and the super cooling reflux AIR discharged from the liquid-AIR separator LAS sequentially enters the super cooling tank UCD, the natural gas cryogenic heat exchanger HXNG-DC, the natural gas shallow Leng Huanre device HXNG-SC and the return normal temperature compressor C1 inlet, wherein part of reflux AIR discharged from the super cooling tank UCD sequentially enters the reflux AIR compressor C-UCA, the natural gas cryogenic heat exchanger HXNG-DC, the reflux AIR expander E-UCA and the super cooling reflux AIR inlet returned to the super cooling tank UCD.

As shown in fig. 7, under the standing condition of the LAES subsystem, the LNG-RG subsystem is operated, a cooling circuit is formed between the shallow cooling tank SCD and the natural gas shallow Leng Huanre device HXNG-SC, and a cooling circuit is formed between the first cryogenic tank DCD1, the second cryogenic tank DCD2, the third cryogenic tank DCD3 and the natural gas cryogenic heat exchanger HXNG-DC.

At this time, the cryogenic energy and the shallow cooling energy of the LNG-RG subsystem are respectively output to the first cryogenic tank DCD1, the second cryogenic tank DCD2, the third cryogenic tank DCD3 and the shallow cooling tank SCD.

As shown in fig. 8, during the discharging operation of the LAES subsystem, the LNG-RG subsystem is operated, a cooling circuit is formed between the shallow cooling tank SCD and the natural gas shallow Leng Huanre device HXNG-SC, and a cooling circuit is formed between the first cryogenic tank DCD1, the second cryogenic tank DCD2, the third cryogenic tank DCD3 and the natural gas cryogenic heat exchanger HXNG-DC.

At this time, the liquid air in the liquid air storage tank is pressurized by the discharge cryopump DCP and then sequentially enters the super-cooling tank, the third cryogenic tank DCD3, the second cryogenic tank DCD2, the first cryogenic tank DCD1, the shallow cooling tank SCD, the heat storage tank HD and the expander E.

The LAES subsystem in the coupling system can be matched with the coupling cooling exchanging subsystem to independently operate, the LNG-RG subsystem can also independently operate, and the LAES subsystem can be coupled with the LNG-RG subsystem to operate through the coupling cooling exchanging subsystem under the charging working condition, the standing working condition and the discharging working condition. The cooling system comprises an LNG-RG subsystem, a LAES subsystem, a coupling cooling exchange subsystem and a cooling exchange subsystem, wherein the LNG-RG subsystem is used for storing cold energy generated by the LNG-RG subsystem, and the coupling cooling exchange subsystem is used for directly storing the cold energy generated by the LNG-RG subsystem. And when the LNG-RG subsystem is out of operation, the LAES subsystem can be matched with the coupled cooling exchanging subsystem to independently operate, and when the LAES subsystem is out of operation, the LNG-RG subsystem can be matched with the coupled cooling exchanging subsystem to independently operate.

To more clearly illustrate the method of implementation and implementation advantages of the present invention, a thermodynamic model of an embodiment was simulated using ASPEN HYSYS software for the embodiment described in fig. 1 of the present disclosure. The simulation results are shown in table 1 below:

TABLE 1 LAES subsystem Key modeling assumptions and simulation results

From the simulation results, the power consumed by the cryogenic compression process is much smaller than that of normal temperature compression, and the power consumed by the cryogenic pump to further compress the ambient air (134.1K, 4.34 MPa) which has entered the supercritical state is much smaller than that of low temperature compression. The LAES subsystem charge and discharge efficiency in Table 1 is achieved with the assistance of ambient heat sources and without accounting for the possible power generated by the LNG-RG subsystem, and the isentropic efficiency of the key equipment is 85% for the compressor, 90% for the expander and 75% for the cryopump, which are all assumed parameters commonly used in the art.

Further, the embodiment of the invention also discloses a coupling method of liquid air energy storage and liquefied natural gas regasification, which can be applied to the coupling system of any one of the above, and specifically comprises the following steps:

The cryogenic energy generated by the LNG-RG subsystem is output to the coupled cold exchange subsystem under any working condition of the LAES subsystem, and is stored in a cryogenic tank to realize the regasification of liquefied natural gas;

in the charging working condition of the LAES subsystem, the ambient air is output to a heat storage tank for storage through compression heat energy generated by normal-temperature compression, and then the ambient air entering and exiting each low-temperature compressor is cooled to a cryogenic temperature through a coupling cooling subsystem, so that the liquefaction of the ambient air is realized;

and under the discharge working condition of the LAES subsystem, the cryogenic energy generated by the LAES subsystem is output and coupled with the cold exchange subsystem, and is stored in a cryogenic tank to realize the regasification of liquid air.

In some embodiments, the coupling method may further comprise:

outputting shallow cold energy generated by the LNG-RG subsystem to a shallow cold tank of the coupled cold exchange subsystem for storage under any working condition of the LAES subsystem;

in the discharging working condition of the LAES subsystem, the shallow cold energy output generated by the LAES subsystem is coupled with the cold exchange subsystem and is stored in a shallow cold tank;

In the charging working condition of the LAES subsystem, firstly, the shallow cold energy in the shallow cold tank is utilized to cool the ambient air to the shallow cold temperature, and then the deep cold energy in the deep cold tank is utilized to cool the ambient air entering and exiting each low-temperature compressor to the deep cold temperature;

And under any working condition of the coupling system, outputting the superfluous shallow cooling energy in the shallow cooling tank to the external application of the coupling system.

In some embodiments, the coupling method may further comprise:

Outputting the super-cooling energy generated by the LAES subsystem to a super-cooling tank for storage under the discharge working condition of the LAES subsystem;

And under the charging working condition of the LAES subsystem, the super-cold energy in the super-cold tank is utilized to cool the ambient air which is discharged from the multi-stage low-temperature compressor and is cooled to the cryogenic temperature by the coupled cooling-exchanging subsystem to the super-cold temperature, wherein the super-cold temperature is the pressurized outlet temperature in the regasification process of the liquid air.

In some embodiments, the coupling method may further comprise:

When the LAES subsystem is in a charging working condition, the ambient air with the temperature reaching the super-cooling temperature sequentially enters a low-temperature expander and a liquid-air separator to generate liquid air and super-cooling reflux air;

wherein, the super-cold return air is recycled by the super-cold tank to be converted into the return air with the cryogenic temperature;

the reflux air with partial cryogenic temperature sequentially enters a reflux air compressor to be compressed and heated, the cryogenic energy in a cryogenic tank of the coupled cooling-exchanging subsystem is cooled to cryogenic temperature, and the reflux air enters a reflux air expander to be expanded and cooled and then is converged into the super-cooled reflux air output by the liquid-air separation tank.

In some embodiments, the coupling method may further comprise:

In the charging working condition of the LAES subsystem, after the compression heat energy is output to the heat storage tank, the ambient air is led into the air purifier to carry out adsorption treatment of carbon dioxide and water, and then the ambient air entering and exiting each low-temperature compressor is cooled to a cryogenic temperature by utilizing the coupling cooling subsystem;

At least part of regasified air discharged through the expander is led into an air purifier for desorption treatment of carbon dioxide and water under the discharge working condition of the LAES subsystem.

It will be appreciated by those skilled in the art that embodiments of the coupling method of embodiments of the present invention may be combined with each other.

In some embodiments, the invention also discloses a coupling method of LAES and LNG-RG, so as to solve the technical problems in the prior art.

In some illustrative embodiments, the coupling method of LAES and LNG-RG comprises the steps of converting ambient air into liquid air for storage under a charging condition, wherein the process comprises the steps of compressing the ambient air at normal temperature, recovering compression heat energy generated by compression, reducing the temperature of the ambient air after normal-temperature compression to the ambient temperature, and carrying out multi-stage low-temperature compression to obtain the ambient air with target pressure, wherein the ambient air before and after each stage of low-temperature compression is cooled to a cryogenic temperature by using cryogenic energy in a cryogenic tank, wherein the cryogenic energy in the cryogenic tank is from a liquefied natural gas regasification process and a liquid air regasification process, the cold end temperature of the cryogenic tank is the cryogenic temperature, the cryogenic temperature is the pressurized outlet temperature in the liquefied natural gas regasification process, the hot end temperature of the cryogenic tank is the shallow cooling temperature, and the shallow cooling temperature is the ambient air outlet temperature after the ambient air is subjected to low-temperature compression.

In some alternative embodiments, the liquefaction phase transition temperature of the ambient air under the target pressure is higher than the cryogenic temperature, the process of cooling the ambient air before and after each stage of low-temperature compression to the cryogenic temperature by utilizing the cryogenic energy in the cryogenic tank comprises the steps of cooling the ambient air after the last stage of low-temperature compression to the cryogenic temperature to obtain the liquid air under the target pressure, converting the ambient air into the liquid air for storage under the charging condition, and further comprises the steps of compressing the liquid air under the target pressure to a higher pressure and then performing low-temperature expansion.

In some alternative embodiments, the process of converting ambient air to liquid air for storage during charging conditions further comprises cooling the ambient air to a shallow cooling temperature using shallow cooling energy in the shallow cooling tank prior to cooling the ambient air to the cryogenic temperature using cryogenic energy in the cryogenic tank, wherein the shallow cooling energy in the shallow cooling tank is from a liquefied natural gas regasification process and a liquid air regasification process.

In some alternative embodiments, the coupling method further comprises the step of converting the liquid air into the regasified air for heating expansion under the discharging condition, wherein the step of recovering the super-cold energy in the regasified air in the regasification process of the liquid air by using the super-cold tank, the step of converting the ambient air into the liquid air for storage under the charging condition, and the step of cooling the ambient air with the target pressure from the cryogenic temperature to the super-cold temperature, wherein the cold end temperature of the super-cold tank is the super-cold temperature, the hot end temperature of the super-cold tank is the super-cold temperature, and the super-cold temperature is the pressurized outlet temperature in the regasification process of the liquid air.

In some alternative embodiments, the process of converting the ambient air into liquid air for storage under the charging working condition further comprises the steps of carrying out low-temperature expansion on the ambient air with super-cooling temperature to generate liquid air and super-cooling reflux air, separating and discharging the super-cooling reflux air, recovering super-cooling energy in the super-cooling reflux air through a super-cooling tank to convert the super-cooling energy into reflux air with cryogenic temperature, compressing at least part of the reflux air with cryogenic temperature, cooling part of the reflux air after compression and heating to cryogenic temperature by utilizing the cryogenic energy in the super-cooling tank, then carrying out low-temperature expansion on the reflux air, and then collecting the part of the reflux air after expansion and cooling into the separated and discharged super-cooling reflux air again.

In some alternative embodiments, the process of converting the ambient air into liquid air for storage under the charging working condition further comprises the steps of adsorbing carbon dioxide and water in the ambient air which is compressed at normal temperature and recovered by heat energy through an air purifier before the multi-stage low-temperature treatment, and the process of converting the ambient air into liquid air for storage under the charging working condition further comprises the step of introducing at least part of the re-gasified air after expansion work into the air purifier for desorption treatment of the carbon dioxide and the water.

As shown in fig. 9, fig. 9 shows steps of a flow of a charging condition and a discharging condition of a LAES subsystem of a coupling system in an embodiment of the present invention, including:

s1, compressing ambient Air at normal temperature to obtain first ambient Air1;

Step S2, after the compression heat energy in the first ambient Air1 is output to the heat storage tank HD, the temperature of the first ambient Air1 is reduced, and a second ambient Air2 is obtained;

s3, outputting shallow cooling energy in the shallow cooling tank SCD to the second ambient Air2, and reducing the temperature of the second ambient Air2 to the shallow cooling temperature to obtain third ambient Air3;

Wherein, the shallow cold energy in the shallow cold tank SCD can come from the regasified natural gas of the LNG-RG subsystem and the regasified air of the LAES subsystem under the discharging working condition;

S4, performing multistage low-temperature compression on the third ambient Air3 to gradually compress the third ambient Air3 to a target pressure to obtain fourth ambient Air4;

Before each stage of low-temperature compression, outputting the cryogenic energy in the cryogenic tank DCD to the third ambient Air3, reducing the temperature of the third ambient Air3 to the cryogenic temperature, and then implementing the low-temperature compression of each stage of the third ambient Air3 with the cryogenic temperature until the multistage low-temperature compression is completed, and cooling the third ambient Air3 to the cryogenic temperature through the cryogenic energy in the cryogenic tank DCD, thereby obtaining fourth ambient Air4 with the cryogenic temperature;

wherein, the cryogenic energy in the cryogenic tank DCD can be from the regasified natural gas of the LNG-RG subsystem and the regasified air of the LAES subsystem under the discharging condition;

Besides the cryogenic energy of the cryogenic tank DCD, the cryogenic energy generated in real time by the LNG-RG subsystem can be directly utilized.

S5, outputting the super-cooling energy in the UCD to the fourth ambient Air4, and reducing the temperature of the fourth ambient Air4 to the super-cooling temperature to obtain the fifth ambient Air5 with the super-cooling temperature, wherein the super-cooling temperature is the pressure outlet temperature in the regasification process of the liquid Air;

Step S6, carrying out adiabatic expansion on the fifth ambient Air5, obtaining a sixth ambient Air6 mixed with gas and liquid in a liquid-Air separator LAS, and storing liquid Air in the sixth ambient Air6 into a liquid Air storage tank LAD;

The super-cold return air obtained in the liquid-air separator LAS can be used for completing super-cold energy, deep cold energy and shallow cold energy recovery of the super-cold return air and super-cold energy regeneration by referring to the embodiment.

Optionally, between steps S2 and S3, the purification treatment of carbon dioxide and water in the second ambient Air2 may be further completed by the Air purifier APU, so as to obtain the second ambient Air2 without carbon dioxide and water.

The liquefaction and storage of the ambient air under the charging condition of the LAES subsystem are completed.

Step S7, releasing liquid Air from a liquid Air storage tank LAD, and pressurizing by a discharge cryopump DCP to obtain seventh ambient Air7 with mixed gas and liquid;

S8, recycling super-cooling energy in the regasified Air in the gas-liquid mixed Air6 through a super-cooling tank UCD, and raising the temperature of the regasified Air to the cryogenic temperature to obtain eighth ambient Air8;

s9, recycling the cryogenic energy in the seventh ambient Air7 through a cryogenic tank DCD, and raising the temperature of the seventh ambient Air7 to the shallow cooling temperature to obtain ninth ambient Air9;

S10, recovering shallow cold energy in ninth ambient Air9 through a shallow cold tank SCD, and raising the temperature of the ninth ambient Air9 to the ambient temperature to obtain tenth ambient Air10;

Step S11, outputting compression heat energy in the heat storage tank HD to the decade-environment Air10 to obtain eleventh environment Air11 with temperature rising expansion, and performing expansion work by using the eleventh environment Air 11;

the compressed heat energy and the environmental heat energy can be output to the tenth environmental Air10 together for further heating expansion.

The regasification and expansion work of the liquid air under the discharging working condition of the LAES subsystem is completed.

And the LNG-RG subsystem can output cold energy to the shallow cooling tank and the deep cooling tank under the charging working condition, the discharging working condition and the standing working condition of the LAES subsystem, and the working condition state of the LAES subsystem is not required to be considered, so that the coupling adaptability of the LNG-RG subsystem and the LAES subsystem can be improved.

The super-cooling temperature, the cryogenic temperature, the shallow cooling temperature and the environmental temperature in the embodiment of the invention are mainly used for distinguishing temperature changes in different areas and different states, and basically, the super-cooling temperature is lower than the cryogenic temperature, the cryogenic temperature is lower than the shallow cooling temperature and the shallow cooling temperature is lower than the environmental temperature.

Illustratively, the super-cooling temperature in the embodiments of the present invention may be in a temperature range between-192 ℃ and-162 ℃, the sub-cooling temperature may be in a temperature range between-162 ℃ and-100 ℃, the sub-cooling temperature may be in a temperature range between-100 ℃ and-30 ℃, and the ambient temperature may be in a temperature range between-30 ℃ and 40 ℃. In some embodiments of the present invention, the temperature of the ambient air flowing out of the compressor may be higher than-30 ℃ by increasing the compression ratio of the compressor during the LAES subsystem charging condition, and in some embodiments of the present invention, the temperature of the ambient air flowing out of the different compressors may be slightly different, which are all embodiments that would be available to one of ordinary skill in the art without inventive effort and are within the scope of the present invention.

In summary, the advantages of the coupling system and the coupling method in the embodiment of the invention include:

1. And a coupling cooling exchange subsystem is established between the LAES subsystem and the LNG-RG subsystem to uniformly manage deep cooling energy and shallow cooling energy, so that the following combined functions are realized:

1.1, inputting deep cooling energy and shallow cooling energy generated under various working conditions in an LNG-RG subsystem and an LAES subsystem into a cold accumulation tank of a coupled cold exchange subsystem, solving the intermittent problem of the cooling energy output of the LNG-RG, and ensuring the centralized storage of the deep cooling energy and the shallow cooling energy;

1.2, realizing centralized output of cryogenic energy, and using LNG-RG cryogenic energy to the greatest extent to manufacture liquid air;

1.3, realizing the centralized output of the shallow cold energy, and externally applying the superfluous shallow cold energy of the output subsystem;

1.4, through the redundant cold energy reserve (for example, after the LAES subsystem discharges) and the heat energy reserve (for example, after the LAES subsystem charges) in the coupled cooling subsystem, the coupled operation of the LNG-RG subsystem and the LAES subsystem under different working conditions can be met in the redundant capacity range, and the independent operation of the LNG-RG subsystem and the LAES subsystem is also supported, so that the coupled adaptability between the LNG-RG subsystem and the LAES subsystem is improved;

And 1.5, the ambient air is compressed by the cryogenic energy which is stored in the coupling cooling subsystem and is mainly provided at the lowest temperature by the cold energy output by the LNG-RG subsystem, the cryogenic energy of the liquefied natural gas regasification of the LNG-RG is fully utilized, the power consumption of a compressor is reduced, and the charge and discharge efficiency of the coupling system is improved.

2. Through the dual-temperature compression mode of normal-temperature compression and multi-stage low-temperature compression, the ambient air is compressed to a certain pressure before the multi-stage low-temperature compression, and then the ambient air cooled to the cryogenic temperature enters the low-temperature compressor, and the advantages of the dual-temperature compression mode include:

2.1, primary normal temperature, namely, firstly compressing at normal temperature to generate compression heat and provide the compression heat for a discharge working condition, wherein the ambient air with a certain compressed ambient temperature is convenient for air purification, dehydration and decarbonization, and the air purification treatment is carried out on the ambient air after the compression heat energy is recovered, so that the carbon dioxide and water in the ambient air are prevented from liquefying or icing in the subsequent process, and partial equipment and pipelines are prevented from being damaged;

2.2, multistage deep cooling, namely after primary compression, the main compression process is completed through multistage low-temperature compression at the deep cooling temperature which is the lowest temperature which can be output by LNG-RG, so that the overall compression power consumption is reduced conveniently.

3. The low-temperature energy storage device can utilize low-cost and even free environmental heat energy to the greatest extent under the discharge working condition of the LAES subsystem, improves the charge and discharge efficiency of the coupling system, and reduces the system cost, wherein the shallow cold energy stored by the coupling cold exchange subsystem can be completely output to external applications, and the normal operation of the coupling system is not affected.

It should be noted that the above embodiments are merely for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.

Claims

1. A LAES and LNG-RG coupled system, comprising: a LAES subsystem, a LNG-RG subsystem, and a coupled cold exchange subsystem;

The LAES subsystem includes: a heat storage tank, a sequentially connected normal temperature compressor, a multi-stage low temperature compressor unit consisting of at least two sequentially connected low temperature compressors, a low temperature expander, a liquid-air separator, a liquid air storage tank, a discharge low temperature pump and an expander;

Among them, the ambient air liquefaction path is composed of the normal temperature compressor, the multi-stage low temperature compressor unit, the low temperature expander, the liquid-air separator and the liquid air storage tank connected in sequence, which is used to convert the ambient air into liquid air;

Among them, the liquid air storage tank, the discharge cryogenic pump and the expander connected in sequence constitute a liquid air regasification path for converting the liquid air into regasified air;

The coupled cooling subsystem at least supports the LNG-RG subsystem in outputting cooling energy to the LAES subsystem, and in storing and releasing cooling energy of the LNG-RG subsystem and the LAES subsystem;

The coupled cold exchange subsystem includes: a cryogenic tank for storing and releasing the cryogenic energy generated by the LNG-RG subsystem and the cryogenic energy generated by the LAES subsystem during discharge; the cold end temperature is the cryogenic temperature, and the hot end temperature is the shallow cooling temperature;

In the charging mode of the LAES subsystem, the ambient air is compressed by the normal temperature compressor in sequence and the compression heat energy is output to the thermal storage tank for storage, then cooled to a cryogenic temperature by the coupled cooling subsystem, then compressed and heated to the shallow cooling temperature by the first-stage low-temperature compressor, and then cooled to the cryogenic temperature by the coupled cooling subsystem to enter the next-stage low-temperature compressor;

The cryogenic temperature is the pressurized outlet temperature during the regasification process of liquefied natural gas, and the shallow cooling temperature is the ambient air outlet temperature after the ambient air is cryogenically compressed.

2. The coupling system according to claim 1, wherein the LAES subsystem further comprises a charging cryopump;

The ambient air liquefaction path is formed by sequentially connecting the normal temperature compressor, the multi-stage low temperature compressor unit, the charging low temperature pump, the low temperature expander, the liquid-air separator and the liquid air storage tank;

Among them, in the charging condition of the LAES subsystem, the ambient air is compressed by the multi-stage low-temperature compressor, then cooled to a cryogenic temperature by the coupled cold exchange subsystem and enters a fully liquefied or supercritical state, then compressed to a higher pressure by the charging low-temperature pump, then cooled to a cryogenic temperature by the coupled cold exchange subsystem, and then enters the low-temperature expander.

3. The coupling system according to claim 1, wherein the LNG-RG subsystem comprises: a liquefied natural gas regasification path for converting liquefied natural gas into regasified natural gas;

The coupled cooling subsystem further includes: a cryogenic charging heat exchanger, a cryogenic discharging heat exchanger, and a natural gas cryogenic heat exchanger;

Wherein, the natural gas cryogenic heat exchanger is provided on the liquefied natural gas regasification path of the LNG-RG subsystem;

Wherein, the cryogenic charging heat exchanger is provided on the ambient air liquefaction path of the LAES subsystem, and is used to cool the ambient air entering and exiting each of the cryogenic compressors to a cryogenic temperature respectively;

Wherein, the cryogenic discharge heat exchanger is provided on the liquid air regasification path of the LAES subsystem, between the discharge cryogenic pump and the expander;

The hot end and the cold end of the cryogenic charging heat exchanger, the cryogenic discharging heat exchanger, and the natural gas cryogenic heat exchanger are respectively connected to the hot end and the cold end of the cryogenic tank.

4. The coupling system according to claim 1, wherein the LNG-RG subsystem comprises: a liquefied natural gas regasification path for converting liquefied natural gas into regasified natural gas;

The coupled cold exchange subsystem further includes: a natural gas cryogenic heat exchanger; the number of the cryogenic tanks is multiple; wherein the cryogenic tank is a solid packed bed, having both cold storage and cold exchange functions;

Each of the cryogenic tanks is provided on both the ambient air liquefaction path and the liquid air regasification path of the LAES subsystem; within the cryogenic tank, the ambient air liquefaction path and the liquid air regasification path have the same path and opposite air flow directions;

Wherein, the cryogenic tank and the cryogenic compressor are arranged alternately on the ambient air liquefaction path, and are used to cool the ambient air entering and discharged from each cryogenic compressor to a cryogenic temperature;

The hot end and the cold end of the natural gas cryogenic heat exchanger are respectively connected to the hot end and the cold end of each cryogenic tank.

5. The coupling system according to claim 1, wherein the coupled cold exchange subsystem further comprises: a shallow cooling tank for storing and releasing the shallow cooling energy generated by the LNG-RG subsystem and the shallow cooling energy generated by the LAES subsystem during discharge operation, wherein the cold end temperature is the shallow cooling temperature and the hot end temperature is the ambient temperature;

Wherein, under any operating condition of the LAES subsystem, the coupled cooling subsystem outputs shallow cooling energy to an external application of the coupled system through the shallow cooling tank.

6. The coupling system according to claim 1, wherein the LAES subsystem further comprises: an ultracold tank for storing and releasing ultracold energy generated during the discharge operation of the LAES subsystem;

In the charging mode of the LAES subsystem, the ambient air discharged from the multi-stage cryogenic compressor unit is cooled to a cryogenic temperature by the coupled cooling subsystem and then sequentially enters the hot end of the super-cold tank, the cryogenic expander, and the liquid-air separator; the super-cold return air output from the liquid-air separator first enters the cold end of the super-cold tank;

Wherein, in the discharge working condition of the LAES subsystem, the regasified air first outputs super-cold energy to the super-cold tank, and then outputs deep cold energy and shallow cold energy to the coupled cooling subsystem;

Among them, the cold end temperature of the super-cold tank is the super-cold temperature, and the hot end temperature is the cryogenic temperature; the super-cold temperature is the pressurized outlet temperature during the regasification process of liquid air.

7. The coupling system according to claim 6, further comprising: a return air compressor and a return air expander;

Among them, in the charging condition of the LAES subsystem, part of the return air flowing out from the hot end of the ultra-cold tank is compressed and heated by the return air compressor in sequence, then cooled to a cryogenic temperature by the coupled cooling subsystem, then expanded and cooled by the return air expander, and finally merged into the ultra-cold return air output from the liquid-air separator.

8. The coupling system according to claim 1, further comprising: an external heat source for providing external thermal energy; in a discharge condition of the LAES subsystem, the thermal storage tank and the external heat source jointly provide compression heat and external thermal energy to the regasified air.

9. The coupling system according to claim 1, characterized in that

The cryogenic tank of the coupled cooling subsystem is a solid packed bed, and the heat exchange device of the coupled cooling subsystem is a heat exchanger; the solid packed bed and the heat exchanger exchange cold energy through a heat exchange medium; or,

The cryogenic tank and heat exchange equipment of the coupled cooling subsystem are integrated into a solid packed bed structure, and the ambient air exchanges cold energy with the cold storage medium in the solid packed bed through the pipe wall of its circulation pipeline.

10. The coupling system according to claim 1 is characterized in that the cryogenic tank of the coupled cooling subsystem includes an insulated container at the hot end and an insulated container at the cold end, and the heat exchange equipment of the coupled cooling subsystem is a heat exchanger, the hot end and the cold end of the heat exchanger are respectively connected to the insulated container at the hot end and the insulated container at the cold end, and the insulated containers are filled with liquid heat exchange medium, and the storage and exchange of cold energy are achieved between the two insulated containers through the liquid heat exchange medium.

11. The coupling system according to claim 1, further comprising: an air purifier provided on the ambient air liquefaction path of the LAES subsystem, between the room temperature compressor and the multi-stage low temperature compressor unit;

In the charging mode of the LAES subsystem, the ambient air is compressed by the normal temperature compressor, and then the compression heat is recovered by the heat storage tank, and then enters the air purifier. After purification, it is cooled to a cryogenic temperature by the coupled cooling subsystem and enters the multi-stage low-temperature compressor unit;

In the discharge operation state of the LAES subsystem, at least a portion of the regasified air output by the expander flows through the air purifier and is then discharged to the environment.

12. A method for coupling LAES and LNG-RG, characterized by comprising: a process of converting ambient air into liquid air for storage under charging conditions, comprising:

Compress the ambient air at room temperature, recover the compression heat energy generated by the compression, reduce the temperature of the ambient air compressed at room temperature to the ambient temperature, and then obtain the ambient air at the target pressure through multi-stage low-temperature compression;

Among them, the cryogenic energy in the cryogenic tank is used to cool the temperature of the ambient air before and after each stage of cryogenic compression to the cryogenic temperature;

The cryogenic energy in the cryogenic tank comes from the liquefied natural gas regasification process and the liquid air regasification process;

Among them, the cold end temperature of the cryogenic tank is the cryogenic temperature, which is the pressurized outlet temperature during the regasification process of liquefied natural gas; the hot end temperature of the cryogenic tank is the shallow cooling temperature, which is the ambient air outlet temperature after the ambient air is low-temperature compressed.

13. The coupling method according to claim 12, wherein the process of converting ambient air into liquid air for storage under the charging condition further comprises:

Before using the deep cooling energy in the deep cooling tank to cool the temperature of the ambient air to the deep cooling temperature, using the shallow cooling energy in the shallow cooling tank to cool the temperature of the ambient air to the shallow cooling temperature;

The shallow cold energy in the shallow cold tank comes from the liquefied natural gas regasification process and the liquid air regasification process.

14. The coupling method according to claim 12, further comprising:

The process of converting liquid air into regasified air for heating and expansion under discharge conditions includes:

Recovering super-cold energy from regasified air during the regasification of liquid air using super-cold tanks;

The process of converting ambient air into liquid air for storage under the charging condition further includes:

cooling the ambient air at the target pressure from a cryogenic temperature to a super-cold temperature;

The cold end temperature of the super-cold tank is a super-cold temperature, and the hot end temperature is a cryogenic temperature; the super-cold temperature is the pressurized outlet temperature during the regasification process of the liquid air.

15. The coupling method according to claim 14, wherein the process of converting ambient air into liquid air for storage under the charging condition further comprises:

Cryogenic expansion of ultra-cold ambient air to produce liquid air and ultra-cold return air;

Separating and discharging the super-cold return air, and recovering super-cold energy in the super-cold return air through the super-cold tank to convert it into return air at a cryogenic temperature;

At least a portion of the return air at the cryogenic temperature is compressed, and the cryogenic energy in the cryogenic tank is used to cool the compressed and heated return air to the cryogenic temperature, and then the return air is subjected to low-temperature expansion, and then the expanded and cooled return air is re-merged into the separated and discharged super-cold return air.

16. The coupling method according to claim 12, wherein the process of converting ambient air into liquid air for storage under the charging condition further comprises:

Before the multi-stage low-temperature treatment, the carbon dioxide and water in the ambient air are adsorbed by an air purifier and the ambient air is compressed at room temperature and the heat energy is recovered;

At least a portion of the regasified air after expansion and work is introduced into the air purifier for desorption treatment of carbon dioxide and water.