Search

CN-122014378-A - Photo-thermal coupling high-temperature compression supercritical liquid air energy storage system and method

CN122014378ACN 122014378 ACN122014378 ACN 122014378ACN-122014378-A

Abstract

The invention discloses a photo-thermal coupling high-temperature compression supercritical liquid air energy storage system which comprises an air compression purification unit, a liquefaction heat exchange unit, a supercritical liquid air storage unit, a cold storage unit, a heat storage unit, a solar heat collection unit and an air expansion power generation unit. When energy is stored, air is liquefied after high-temperature compression with a high pressure ratio, is directly stored in a supercritical pressure state, compression heat is introduced into a heat storage unit and the grade of heat energy is pulled up by a solar heat collection unit, and when energy is released, supercritical liquid air is directly output without a pump, and high-grade heat energy is utilized for heating, multistage reheating, expansion and working, and cold energy is recovered in a closed loop. The invention eliminates the traditional throttle valve and the pressure pump through supercritical high-pressure storage, eliminates throttle and pressure loss, greatly improves the liquefaction rate, remarkably improves the grade of a heat source through deep coupling of photo-thermal and compression thermal, and greatly improves the generating capacity and the integral circulation efficiency of the system.

Inventors

  • ZHE XIAOHUI
  • HAN FEI
  • WANG CHEN
  • HAN PENG
  • LU XINLIANG

Assignees

  • 石家庄铁道大学

Dates

Publication Date
20260512
Application Date
20260407

Claims (9)

  1. 1. A photo-thermal coupling high temperature compressed supercritical liquid air energy storage system, comprising: The air compression and purification unit (100) is used for compressing and purifying external air and outputting the compressed and purified external air to the liquefaction heat exchange unit; the liquefaction heat exchange unit is used for cooling the compressed and purified air and outputting liquid air to the liquid air storage unit (400), wherein the liquefaction heat exchange unit comprises a flow divider (200) and a cold box (300); a liquid air storage unit (400) for storing liquid air in a supercritical pressure state and outputting the liquid air to the air expansion power generation unit (600) in a power release stage; The cold storage unit (500) is connected with the liquefaction heat exchange unit and the air expansion power generation unit (600) and is used for receiving low-temperature working medium cold energy generated in the energy release process of the air expansion power generation unit (600) and returning the low-temperature working medium cold energy to the liquefaction heat exchange unit; the heat storage unit (700) is connected with the air compression and purification unit (100) and the air expansion power generation unit (600) and is used for receiving heat formed in the compression process of the air compression and purification unit (100) and supplying heat to the air expansion power generation unit (600); The solar heat collection unit (800) is connected with the heat storage unit (700) and is used for heating the heat carrier from the heat storage unit by solar energy and then sending the heat carrier back to the heat storage unit (700); The air expansion power generation unit (600) is connected with the liquid air storage unit (400), the cold storage unit (500) and the heat storage unit (700) and is used for enabling liquid air from the liquid air storage unit (400) to sequentially perform heat absorption gasification, heating up and graded expansion work; the system is coupled and connected with a low-temperature cold loop through high-temperature compression heat recovery and a solar heat collection loop to form a closed-loop energy management system.
  2. 2. The supercritical liquid air energy storage system of claim 1, wherein the output pressure of the liquid air storage unit (400) is higher than the liquid air critical pressure, such that the liquid air is maintained at the supercritical pressure state after being output from the liquid air storage unit (400) before entering the air expansion power generation unit (600).
  3. 3. The supercritical liquid air energy storage system according to claim 1, wherein the air compression purification unit (100) comprises a plurality of stages of compressors arranged in series, a cooler arranged between the compressors of each stage, and an air purification device, wherein the outlets of the compressors of each stage are respectively connected with the heat storage unit (700) through pipelines so as to introduce compression heat of different temperature grades into the heat storage unit (700) for graded heat storage.
  4. 4. The supercritical liquid air energy storage system of claim 1, wherein the heat storage unit (700) comprises a high temperature heat storage branch connected with the solar heat collection unit and a medium temperature heat storage branch connected with the preheating stage in the air expansion power generation unit (600) to provide heat sources of different temperature levels for different expansion stages, respectively.
  5. 5. The supercritical liquid air energy storage system according to claim 1, wherein the cold storage unit (500) is disposed between the air expansion power generation unit (600) and the liquefaction heat exchange unit, and the low-temperature gaseous working medium discharged from the air expansion power generation unit (600) enters the cold storage unit (500) for cold energy storage, and then the cold storage unit (500) releases cold energy to the liquefaction heat exchange unit.
  6. 6. The supercritical liquid air energy storage system of claim 1, wherein the air expansion power generation unit (600) comprises an evaporator, a preheater, a multi-stage heater, and a multi-stage air turbine, wherein the liquid air from the liquid air storage unit (400) is gasified by the evaporator and then forms a staged heated, staged expansion process by alternating a plurality of heating stages and expansion stages.
  7. 7. The supercritical liquid air energy storage system of claim 6 wherein at least one of said multi-stage heaters is connected to said high temperature heat storage branch and at least another stage is connected to said medium temperature heat storage branch such that heat sources of different temperature levels are respectively connected to different expansion stages.
  8. 8. The supercritical liquid air energy storage system of claim 1 wherein, The solar heat collection unit (800) comprises a trough type solar heat collector (801) and a heat carrier circulation loop, wherein the heat carrier circulation loop is connected with the heat storage unit (700) for storing heat energy.
  9. 9. A method of storing and releasing energy using the system of any one of claims 1 to 8, comprising: in the energy storage stage, outside air is compressed, cooled and purified and then sent to a liquefaction heat exchange unit for liquefaction, and the obtained liquid air is stored in a liquid air storage unit (400) in a supercritical pressure state; In the energy storage stage, heat formed in the air compression process is guided into the heat storage unit, and a heat carrier in the heat storage unit enters the solar heat collection unit (800) for heating; In the energy release stage, outputting liquid air in the liquid air storage unit (400) to the air expansion power generation unit (600), and outputting mechanical energy after gasification, preheating, multi-stage heating and multi-stage expansion; In the energy release stage, the expanded low-temperature working medium is guided into the cold storage unit (500) to store cold energy, and the cold energy in the cold storage unit (500) is returned to the liquefaction heat exchange unit to participate in the subsequent liquefaction process.

Description

Photo-thermal coupling high-temperature compression supercritical liquid air energy storage system and method Technical Field The invention belongs to the technical field of liquid air energy storage, and particularly relates to a photo-thermal coupling high-temperature compression supercritical liquid air energy storage system and a method. Background With the transformation of global energy structures and the promotion of 'double carbon' targets, large-scale and high-efficiency energy storage technologies become key to support large-scale access of renewable energy sources. Liquid Air Energy Storage (LAES) has received great attention as an energy storage technology that does not depend on specific geographical conditions, has a high energy storage density, and has a low environmental impact. However, the conventional LAES technology mainly has the following technical bottlenecks: (1) Low energy storage density and efficiency conventional LAES typically employ atmospheric or near-atmospheric (well below the critical pressure of air) storage of liquid air. The low-pressure storage mode not only causes low energy density of the storage medium, but also requires a liquid pump consuming a large amount of energy to pressurize during the cyclic conversion to high pressure, and the overall energy storage efficiency of the system is severely restricted along with obvious throttling loss (energy loss), and the cyclic efficiency is usually only about 40% -50%. (2) The utilization rate of heat energy is low, in the traditional LAES energy release process, liquid air is throttled and depressurized and then subjected to heat absorption, gasification and expansion work, and the temperature of working medium is low. Even if the medium-low grade waste heat generated in the air compression process is recovered, the expansion work is difficult to be obviously improved, so that the generated energy is insufficient, and particularly when the low-grade industrial waste heat is utilized or a sufficient high-temperature heat source cannot be obtained, the system performance is limited. These problems collectively result in the traditional LAES technology being difficult to meet the needs of large-scale deployment in terms of economy and competitiveness. Disclosure of Invention The invention aims to solve the key technical problems of low energy storage density, low circulation efficiency, insufficient energy recycling, particularly high power consumption of a booster pump, serious throttling loss, poor low-grade heat source utilization effect and the like in the existing liquid air energy storage technology, so as to realize a supercritical liquid air energy storage system with higher energy utilization efficiency and better economical efficiency. In order to achieve the purpose, the invention adopts the following technical scheme that the photo-thermal coupling high-temperature compression supercritical liquid air energy storage system comprises: The air compression and purification unit is used for compressing and purifying external air and outputting the compressed and purified external air to the liquefaction heat exchange unit; The liquefaction heat exchange unit is used for cooling the compressed and purified air and outputting liquid air to the liquid air storage unit, wherein the liquefaction heat exchange unit comprises a flow divider and a cold box; The liquid air storage unit is used for storing liquid air in a supercritical pressure state and outputting the liquid air to the air expansion power generation unit in an energy release stage; the cold storage unit is connected with the liquefaction heat exchange unit and the air expansion power generation unit and is used for receiving low-temperature working medium cold energy generated in the energy release process of the air expansion power generation unit and returning the low-temperature working medium cold energy to the liquefaction heat exchange unit; the heat storage unit is connected with the air compression and purification unit and the air expansion power generation unit and is used for receiving heat formed in the compression process of the air compression and purification unit and supplying heat to the air expansion power generation unit; the solar heat collection unit is connected with the heat storage unit and is used for heating the heat carrier from the heat storage unit by solar energy and then sending the heat carrier back to the heat storage unit; the air expansion power generation unit is connected with the liquid air storage unit, the cold storage unit and the heat storage unit and is used for enabling the liquid air from the liquid air storage unit to sequentially perform heat absorption gasification, heating and temperature rising and graded expansion work; the system is coupled and connected with a low-temperature cold loop through high-temperature compression heat recovery and a solar heat collection loop to form a closed-loop energy management