Liquid air low-temperature cold energy multi-stream heat exchange and cascade storage device and method

Abstract

The invention belongs to the technical field of liquid air energy storage and cold energy storage, and particularly relates to a liquid air low-temperature cold energy multi-stream heat exchange and cascade storage device and method.The liquid air low-temperature cold energy multi-stream heat exchange and cascade storage device comprises a liquid air storage tank, a low-temperature pump, a multi-stream heat exchanger, a heater, an expansion unit, a cold storage packed bed and a cold storage material. Liquid air is pressurized by the low-temperature pump and then enters the multi-stream heat exchanger, cold energy is released, the liquid air becomes normal-temperature air, the normal-temperature air drives the expansion unit to generate power after passing through the heater, and the normal-temperature air after power generation enters the multi-stream heat exchanger, absorbs the cold energy released by the liquid air and then is stored in the cold storage material in the cold storage packed bed in a cascade mode. The air generated after expansion power generation is used as a heat transfer medium, the air excess pressure is fully used as driving force, and an additional fan is not needed. In addition, air subjected to expansion power generation flows back for multiple times to exchange heat with liquid air, physical property matching of fluid is achieved, the heat transfer temperature difference is reduced, and low-temperature cold energy is fully recycled.

Description

Technical Field

[0001] The present invention belongs to the technical fields of liquid air energy storage and cold energy storage, and particularly relates to a multi-stream heat exchange and cascade storage device and method for low-temperature cold energy of liquid air. Background Technique

[0002] At present, with the rapid development of liquid air energy storage technology, the efficient recovery and storage of low-temperature cold energy have become the core challenges for improving the energy density and cycle efficiency of the system.

[0003] The traditional recovery of liquid air cold energy mostly relies on a single-stage cold storage packed bed or a simple heat exchange process. As the liquid air gasifies, its temperature gradually rises from -192°C to the ambient temperature. The specific heat capacity and temperature adaptation range of the cold storage material in single-stage storage are limited, resulting in a large heat transfer temperature difference and serious irreversible losses during the cold energy recovery process. In addition, since the air after expansion power generation needs to be forced to circulate to participate in cold energy recovery, the traditional system usually relies on an external fan to provide power, which not only increases energy consumption but also introduces additional equipment, resulting in limited system compactness and economy. Therefore, there is an urgent need to develop a system with low cost and high storage capacity. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide a multi-stream heat exchange and cascade storage device and method for low-temperature cold energy of liquid air, which can effectively achieve the physical property matching of fluids, reduce the heat transfer temperature difference, and fully recover low-temperature cold energy.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: A multi-stream heat exchange and cascade storage device for low-temperature cold energy of liquid air, comprising a power generation unit and a cold energy recovery and storage unit, and the power generation unit is connected to the cold energy recovery and storage unit; The power generation unit includes a liquid air storage tank, a cryogenic pump, a multi-stream heat exchanger, a heater, and an expansion unit; The outlet of the liquid air storage tank is connected to the cryogenic pump, the outlet of the cryogenic pump is connected to the multi-stream heat exchanger, the multi-stream heat exchanger is connected to the inlet of the heater, and the outlet of the heater is connected to the inlet of the expansion unit; The power generation unit heats the liquid air in the liquid air storage tank to form high-temperature and high-pressure air, and drives the expansion unit to generate electricity.

[0006] Preferably, the cold energy recovery and storage unit includes a first cold storage packed bed, a second cold storage packed bed, and a third cold storage packed bed. The first cold storage packed bed, the second cold storage packed bed, and the third cold storage packed bed are respectively filled with a first cold storage material, a second cold storage material, and a third cold storage material; The outlet of the expansion unit is connected to the multi-stream heat exchanger, the outlet of the multi-stream heat exchanger is connected to the inlet of the first cold storage packed bed, the outlet of the first cold storage packed bed is connected to the multi-stream heat exchanger, the multi-stream heat exchanger is connected to the inlet of the second cold storage packed bed, the outlet of the second cold storage packed bed is connected to the multi-stream heat exchanger, the multi-stream heat exchanger is connected to the inlet of the third cold storage packed bed, and the outlet of the third cold storage packed bed is connected to the atmosphere; The cold energy recovery and storage unit cascades the normal temperature air after power generation through the multi-stream heat exchanger to transfer the cold energy of the liquid air to the cold storage material in the cold storage packed bed.

[0007] Preferably, the first cold storage packed bed, the second cold storage packed bed, and the third cold storage packed bed are connected in cascade.

[0008] Preferably, the multi-stream heat exchanger adopts a countercurrent structure, and the liquid air flow channel and the normal temperature air flow channel form a multi-pass cross heat exchange arrangement.

[0009] The present invention also provides a method for multi-stream heat exchange and cascade storage of low-temperature cold energy of liquid air, which adopts a device for multi-stream heat exchange and cascade storage of low-temperature cold energy of liquid air as described above, including a power generation process and a cold energy recovery and storage process; Power generation process: Liquid air flows out from the liquid air storage tank, is pressurized by a cryogenic pump and then enters the multi-stream heat exchanger, releases cold energy and becomes normal temperature air, and then enters the heater to be heated to form high-temperature and high-pressure air to drive the expansion unit to generate electricity; Cold energy recovery and storage process: The normal temperature air after power generation enters the multi-stream heat exchanger to absorb the cold energy released by the liquid air, the temperature decreases and becomes low-temperature air, enters the first cold storage packed bed, transfers the cold energy to the first cold storage material, becomes normal temperature air again, flows into the multi-stream heat exchanger again to absorb the cold energy released by the liquid air, the temperature decreases and becomes low-temperature air, enters the second cold storage packed bed, transfers the cold energy to the second cold storage material, becomes normal temperature air again, passes through the multi-stream heat exchanger again to absorb the cold energy released by the liquid air, enters the third cold storage packed bed, transfers the cold energy to the third cold storage material, and becomes normal temperature air again and is discharged into the atmosphere.

[0010] By adopting the above technical solution: After the liquid air is pressurized by the cryogenic pump, it enters the multi-stream heat exchanger, releases cold energy and becomes normal temperature air. The normal temperature air drives the expansion unit to generate electricity after passing through the heater. The normal temperature air after power generation enters the multi-stream heat exchanger, absorbs the cold energy released by the liquid air, and then is cascaded and stored in the cold storage material inside the cold storage packed bed.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses the air after expansion power generation as the heat transfer medium, and fully utilizes the residual pressure of the air as the driving force, without the need for an additional fan. The system structure is simple, reducing the investment cost.

[0012] 2. The present invention uses the air after expansion power generation to flow back multiple times to exchange heat with the liquid air, achieving the physical property matching of the fluid, reducing the heat transfer temperature difference, and fully recovering the low-temperature cold energy.

[0013] 3. The present invention uses the cold storage packed beds arranged in series to ensure the stable temperature of the reflux air and fully store the low-temperature cold energy of the liquid air. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the present invention.

[0015] REFERENCE SIGNS: 1 - Liquid air storage tank, 2 - Cryogenic pump, 3 - Multi-stream heat exchanger, 4 - Heater, 5 - Expansion unit, 6 - First cold storage packed bed, 7 - Second cold storage packed bed, 8 - Third cold storage packed bed, 9 - 1 - First cold storage material, 9 - 2 - Second cold storage material, 9 - 3 - Third cold storage material. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0018] To effectively achieve the physical property matching of the fluid, reduce the heat transfer temperature difference, and fully recover the low-temperature cold energy, the present invention provides a multi-stream heat exchange and cascade storage device and method for low-temperature cold energy of liquid air, which includes a power generation process and a cold energy recovery and storage process. The present invention uses the air after expansion power generation as the heat transfer medium and fully utilizes the residual pressure of the air as the driving force, without the need for an additional fan. The system structure is simple, reducing the investment cost; on the other hand, it uses the air after expansion power generation to flow back multiple times to exchange heat with the liquid air, achieving the physical property matching of the fluid, reducing the heat transfer temperature difference, and fully recovering the low-temperature cold energy.

[0019] As Figure 1 shown, a multi-stream heat exchange and cascade storage device for cryogenic energy of liquid air includes a power generation unit and a cryogenic energy recovery and storage unit: The power generation unit heats the liquid air in the liquid air storage tank 1 to form high-temperature and high-pressure air, driving the expansion unit 5 to generate electricity; The cryogenic energy recovery and storage unit cascades the cold energy of the liquid air to the cryogenic energy storage material in the cryogenic energy storage packed bed through the multi-stream heat exchanger 3 for the normal-temperature air after power generation.

[0020] Specifically, the power generation unit includes a liquid air storage tank 1, a cryogenic pump 2, a multi-stream heat exchanger 3, a heater 4 and an expansion unit 5.

[0021] The outlet of the liquid air storage tank 1 is connected to the cryogenic pump 2, the outlet of the cryogenic pump 2 is connected to the multi-stream heat exchanger 3, the multi-stream heat exchanger 3 is connected to the inlet of the heater 4, and the outlet of the heater 4 is connected to the inlet of the expansion unit 5.

[0022] Specifically, the cryogenic energy recovery and storage unit includes a first cryogenic energy storage packed bed 6, a second cryogenic energy storage packed bed 7 and a third cryogenic energy storage packed bed 8, and a first cryogenic energy storage material 9-1, a second cryogenic energy storage material 9-2 and a third cryogenic energy storage material 9-3 are respectively filled in the first cryogenic energy storage packed bed 6, the second cryogenic energy storage packed bed 7 and the third cryogenic energy storage packed bed 8; The outlet of the expansion unit 5 is connected to the multi-stream heat exchanger 3, the outlet of the multi-stream heat exchanger 3 is connected to the inlet of the first cryogenic energy storage packed bed 6, the outlet of the first cryogenic energy storage packed bed 6 is connected to the multi-stream heat exchanger 3, the multi-stream heat exchanger 3 is connected to the inlet of the second cryogenic energy storage packed bed 7, the outlet of the second cryogenic energy storage packed bed 7 is connected to the multi-stream heat exchanger 3, the multi-stream heat exchanger 3 is connected to the inlet of the third cryogenic energy storage packed bed 8, and the outlet of the third cryogenic energy storage packed bed 8 is connected to the atmosphere.

[0023] Specifically, the first cryogenic energy storage packed bed 6, the second cryogenic energy storage packed bed 7 and the third cryogenic energy storage packed bed 8 are connected in cascade.

[0024] Specifically, the multi-stream heat exchanger 3 adopts a countercurrent structure, and the liquid air flow channel and the normal-temperature air flow channel form a multi-process cross heat exchange arrangement.

[0025] In this embodiment, after the liquid air is pressurized by the cryogenic pump, it enters the multi-stream heat exchanger, releases cold energy and becomes normal-temperature air. The normal-temperature air drives the expansion unit to generate electricity after passing through the heater. The normal-temperature air after power generation enters the multi-stream heat exchanger, absorbs the cold energy released by the liquid air, and then is cascaded and stored in the cryogenic energy storage material inside the cryogenic energy storage packed bed.

[0026] A method for multi-stream heat exchange and cascade storage of cryogenic energy of liquid air, which is realized based on the above-mentioned multi-stream heat exchange and cascade storage device of cryogenic energy of liquid air, includes a power generation process and a cryogenic energy recovery and storage process.

[0027] Power generation process: Liquid air flows out from the liquid air storage tank 1, is pressurized by the cryogenic pump 2 and then enters the multi-stream heat exchanger 3, releases cryogenic energy and becomes normal-temperature air, and then enters the heater 4 to be heated to form high-temperature and high-pressure air, which drives the expansion unit 5 to generate electricity.

[0028] Cryogenic energy recovery and storage process: The normal-temperature air after power generation enters the multi-stream heat exchanger 3 to absorb the cryogenic energy released by the liquid air, the temperature drops and becomes low-temperature air, enters the first cold storage packed bed 6, transfers the cryogenic energy to the first cold storage material 9-1, and becomes normal-temperature air again. Then it flows into the multi-stream heat exchanger 3 again to absorb the cryogenic energy released by the liquid air, the temperature drops and becomes low-temperature air, enters the second cold storage packed bed 7, transfers the cryogenic energy to the second cold storage material 9-2, and becomes normal-temperature air again. Then it passes through the multi-stream heat exchanger 3 again to absorb the cryogenic energy released by the liquid air, enters the third cold storage packed bed 8, transfers the cryogenic energy to the third cold storage material 9-3, and becomes normal-temperature air and is discharged into the atmosphere.

[0029] The method provided in this embodiment is based on the above-mentioned system embodiments. For the specific process and detailed content, please refer to the above embodiments and will not be elaborated here.

[0030] In summary, the present invention uses the air after expansion power generation as the heat transfer medium, and fully utilizes the residual pressure of the air as the driving force without an additional fan. In addition, the present invention uses the air after expansion power generation to flow back multiple times to exchange heat with the liquid air, realizes the physical property matching of the fluid, reduces the heat transfer temperature difference, and fully recovers the cryogenic energy.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stream heat exchange and cascade storage device for cryogenic cold energy of liquid air, characterized in that It includes a power generation unit and a cold energy recovery and storage unit, and the power generation unit is connected to the cold energy recovery and storage unit; The power generation unit includes a liquid air storage tank (1), a cryogenic pump (2), a multi-stream heat exchanger (3), a heater (4) and an expansion unit (5); The outlet of the liquid air storage tank (1) is connected to the cryogenic pump (2), the outlet of the cryogenic pump (2) is connected to the multi-stream heat exchanger (3), the multi-stream heat exchanger (3) is connected to the inlet of the heater (4), and the outlet of the heater (4) is connected to the inlet of the expansion unit (5); The power generation unit heats up the liquid air in the liquid air storage tank (1) to form high-temperature and high-pressure air, and drives the expansion unit (5) to generate electricity.

2. The multi-stream heat exchange and cascade storage device for cryogenic cold energy of liquid air according to claim 1, characterized in that The cold energy recovery and storage unit includes a first cold storage packed bed (6), a second cold storage packed bed (7) and a third cold storage packed bed (8), and the first cold storage packed bed (6), the second cold storage packed bed (7) and the third cold storage packed bed (8) are respectively filled with a first cold storage material (9-1), a second cold storage material (9-2) and a third cold storage material (9-3); The outlet of the expansion unit (5) is connected to the multi-stream heat exchanger (3), the outlet of the multi-stream heat exchanger (3) is connected to the inlet of the first cold storage packed bed (6), the outlet of the first cold storage packed bed (6) is connected to the multi-stream heat exchanger (3), the multi-stream heat exchanger (3) is connected to the inlet of the second cold storage packed bed (7), the outlet of the second cold storage packed bed (7) is connected to the multi-stream heat exchanger (3), the multi-stream heat exchanger (3) is connected to the inlet of the third cold storage packed bed (8), and the outlet of the third cold storage packed bed (8) is connected to the atmosphere; The cold energy recovery and storage unit cascades the cold energy of the liquid air to the cold storage materials in the cold storage packed beds through the multi-stream heat exchanger (3) for the normal-temperature air after power generation.

3. The multi-stream heat exchange and cascade storage device for cryogenic cold energy of liquid air according to claim 2, wherein The first cold storage packed bed (6), the second cold storage packed bed (7) and the third cold storage packed bed (8) are connected in cascade.

4. The multi-stream heat exchange and cascade storage device for cryogenic cold energy of liquid air according to claim 1, characterized in that, The multi-stream heat exchanger (3) adopts a countercurrent structure, and the liquid air flow channel and the normal-temperature air flow channel form a multi-process cross heat exchange arrangement.

5. A multi-stream heat exchange and cascade storage method for cryogenic cold energy of liquid air, which uses a multi-stream heat exchange and cascade storage device for cryogenic cold energy of liquid air according to any one of claims 1-4, characterized in that, It includes a power generation process and a cold energy recovery and storage process; Power generation process: The liquid air flows out of the liquid air storage tank (1), is pressurized by the cryogenic pump (2) and then enters the multi-stream heat exchanger (3), releases cold energy and becomes normal-temperature air, and then enters the heater (4) to be heated to form high-temperature and high-pressure air, driving the expansion unit (5) to generate electricity; Cold energy recovery and storage process: The normal-temperature air after power generation enters the multi-stream heat exchanger (3) to absorb the cold energy released by the liquid air, and its temperature drops to become low-temperature air. Then it enters the first cold storage packed bed (6), transfers the cold energy to the first cold storage material (9-1), and becomes normal-temperature air again. It then flows into the multi-stream heat exchanger (3) again to absorb the cold energy released by the liquid air, its temperature drops to become low-temperature air, enters the second cold storage packed bed (7), transfers the cold energy to the second cold storage material (9-2), and becomes normal-temperature air again. It then passes through the multi-stream heat exchanger (3) again to absorb the cold energy released by the liquid air, enters the third cold storage packed bed (8), transfers the cold energy to the third cold storage material (9-3), and becomes normal-temperature air again before being discharged into the atmosphere.

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