CN221703799U - High temperature type compressed carbon dioxide energy storage system - Google Patents

Abstract

The utility model discloses a high-temperature compressed carbon dioxide energy storage system, which comprises: the system comprises a gas storage bag, a first compressor, a first heat storage unit, a second compressor, a third heat storage unit, a liquefying unit, a valve, a liquid CO ₂ storage tank, a first expander, a second expander and a radiator; the first compressor compresses carbon dioxide to a supercritical state; the first heat storage unit and the second heat storage unit are used for storing compression heat generated by first-stage compression; the third heat storage unit is used for storing compression heat generated by the second-stage compression. The high-temperature type compressed carbon dioxide energy storage system provided by the utility model adopts a high-pressure-ratio high-temperature compression scheme, so that the work amount of carbon dioxide per unit mass is greatly increased, the volume of a flexible gas storage bag is effectively reduced, meanwhile, the high-pressure carbon dioxide adopts a self-condensation circulation technology, no external cold source is required, the efficiency of the energy storage system is improved, and the investment cost is reduced.

Description

A high temperature compressed carbon dioxide energy storage system

Technical Field

The utility model belongs to the technical fields of renewable energy power generation, grid peak regulation and compressed gas energy storage, and specifically relates to a high-temperature compressed carbon dioxide energy storage system.

Background Art

Compressed carbon dioxide energy storage technology is a closed-loop system that includes two gas storage devices that store low-pressure and high-pressure carbon dioxide respectively, which are used to define the beginning and end of the storage/release process. The current compressed carbon dioxide energy storage technology differs due to the different storage forms of carbon dioxide at the low-pressure end: when the low-pressure carbon dioxide is stored in a supercritical state, the pressure level of the compressed carbon dioxide is too high, which will pose challenges to the cost and technology of the gas storage device at the high-pressure end; when the low-pressure carbon dioxide is stored in a liquid state, it is necessary to add additional condensation and evaporation devices at the inlet and outlet of the gas storage device, and the system efficiency is low; some scholars have proposed storing low-pressure carbon dioxide in a flexible gas storage bag as a gas close to the ambient state, but the huge volume of the gas storage bag limits the widespread promotion of this type of compressed carbon dioxide energy storage, and the use of refrigeration units to liquefy high-pressure carbon dioxide significantly reduces the efficiency of the energy storage system and increases the investment cost.

Therefore, there is an urgent need for a high-temperature compressed carbon dioxide energy storage system.

Utility Model Content

The purpose of the utility model is to provide a high-temperature compressed carbon dioxide energy storage system to solve one or more of the above-mentioned technical problems. The high-temperature compressed carbon dioxide energy storage system provided by the utility model adopts a high-pressure-to-high-temperature compression scheme, which greatly increases the work per unit mass of carbon dioxide and effectively reduces the volume of the flexible gas storage bag. At the same time, the high-pressure carbon dioxide adopts self-condensation cycle technology, and does not require an additional cold source from the outside, so the efficiency of the energy storage system is improved and the investment cost is reduced.

In order to achieve the above purpose, the utility model adopts the following technical solutions:

A high-temperature compressed carbon dioxide energy storage system, comprising: a gas storage bag, a first compressor, a first heat storage unit, a second heat storage unit, a second compressor, a third heat storage unit, a liquefaction unit, a valve, a liquid _CO2 storage tank, a first expander, a second expander, and a radiator; the gas storage bag is connected to the first compressor, the first heat storage unit, the second heat storage unit, the second compressor, the third heat storage unit, the liquefaction unit, the valve, and the liquid _CO2 storage tank in sequence; the liquid _CO2 storage tank, the liquefaction unit, the third heat storage unit, the first expander, the second heat storage unit, the first heat storage unit, the second expander, the radiator, and the gas storage bag are connected in sequence;

The first compressor compresses the carbon dioxide to a supercritical state;

The first heat storage unit and the second heat storage unit are used to store compression heat generated by the first stage compression;

The third heat storage unit is used to store compression heat generated by the second stage compression;

The first heat storage cycle includes: a first heat exchanger, a first hot storage tank, a sixth heat exchanger, and a first cold storage tank; the outlet of the first cold storage tank is connected to the inlet of the first hot storage tank through the cold side channel of the first heat exchanger, and the outlet of the first hot storage tank is connected to the inlet of the first cold storage tank through the hot side channel of the sixth heat exchanger;

The second heat storage cycle includes: a second heat exchanger, a second hot storage tank, a fifth heat exchanger, and a second cold storage tank; the outlet of the second cold storage tank is connected to the inlet of the second hot storage tank through the cold side channel of the second heat exchanger, and the outlet of the second hot storage tank is connected to the inlet of the second cold storage tank through the hot side channel of the fifth heat exchanger;

The third heat storage cycle includes: a third heat exchanger, a third hot storage tank, a fourth heat exchanger, and a third cold storage tank; the outlet of the third cold storage tank is connected to the inlet of the third hot storage tank through the cold side channel of the third heat exchanger, and the outlet of the third hot storage tank is connected to the inlet of the third cold storage tank through the hot side channel of the fourth heat exchanger;

The liquefaction unit includes: a condenser, a fourth hot storage tank, an evaporator, and a fourth cold storage tank; the hot side channel inlet of the condenser is connected to the hot side channel outlet of the third heat exchanger, and the outlet is connected to the liquid _CO2 storage tank inlet through a valve; the saturated gaseous carbon dioxide released from the valve outlet enters the second compressor inlet through the return air; the cold side channel inlet of the evaporator is connected to the liquid _CO2 storage tank outlet, and the outlet is connected to the cold side channel inlet of the fourth heat exchanger.

A further improvement of the utility model is that the gas storage bag is composed of a flexible air bag, the volume of which changes momentarily with the amount of gas stored, so that the carbon dioxide inside is always stored under ambient pressure.

A further improvement of the utility model is that the first stage compression of the compression unit is high pressure ratio compression, and the high temperature can reach 450-550°C, which can effectively improve the work capacity of the unit working fluid;

Furthermore, a radiator is provided at the outlet of the second expander.

A further improvement of the utility model is that a circulation pump (not shown in the figure) is provided at the outlet of each hot storage tank and each cold storage tank.

A further improvement of the utility model is that the heat storage medium stored in the first hot storage tank and the first cold storage tank is molten salt; the heat storage medium stored in the second hot storage tank, the second cold storage tank, the third hot storage tank, the third cold storage tank, the fourth hot storage tank, and the fourth cold storage tank is liquid water.

Compared with the existing technology, the beneficial effects of the utility model are:

1. The utility model provides a high-temperature compressed carbon dioxide energy storage system, which compresses carbon dioxide in an ambient state to a high-temperature and high-pressure state at a high-pressure ratio, uses molten salt as a high-temperature heat storage medium to store heat, and uses pressurized water as a low-temperature heat storage medium to store heat, thereby improving the work capacity of the unit mass of the working fluid and reducing the volume of the gas storage bag;

2. The high-temperature compressed carbon dioxide energy storage system provided by the utility model adopts a self-condensing cycle for high-pressure carbon dioxide liquefaction, does not require an additional cold source, improves system efficiency and reduces system operating costs.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art; obviously, the drawings described below are some embodiments of the utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic diagram of a high-temperature compressed carbon dioxide energy storage system according to an embodiment of the present utility model;

In Figure 1, 1, gas storage bag; 2, first compressor; 3, second compressor; 4, condenser; 5, valve; 6, liquid _CO2 storage tank; 7, evaporator; 8, first expander; 9, second expander; 10, radiator; 11, first heat exchanger; 12, first hot storage tank; 13, sixth heat exchanger; 14, first cold storage tank; 15, second heat exchanger; 16, second hot storage tank; 17, fifth heat exchanger; 18, second cold storage tank; 19, third heat exchanger; 20, third hot storage tank; 21, fourth heat exchanger; 22, third cold storage tank; 23, fourth hot storage tank; 24, fourth cold storage tank.

DETAILED DESCRIPTION

In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

The utility model is further described in detail below with reference to the accompanying drawings:

Please refer to Figure 1. A high-temperature compressed carbon dioxide energy storage system of the utility model includes: a gas storage bag 1, a first compressor 2, a first heat storage unit, a second heat storage unit, a second compressor 3, a third heat storage unit, a liquefaction unit, a valve 5, a liquid CO2 storage tank 6, a first expander 8, a second expander 9, and a radiator 10; the gas storage bag 1 is connected to the first compressor 2, the first heat storage unit, the second heat storage unit, the second compressor 3, the third heat storage unit, the liquefaction unit, the valve 5, and the liquid _CO2 storage tank 6 in sequence; the liquid _CO2 storage tank 6, the liquefaction unit, the third heat storage unit, the first expander 8, the second heat storage unit, the first heat storage unit, the second expander 9, the radiator 10, and the gas storage bag 1 are connected in sequence;

The first compressor compresses the carbon dioxide to a supercritical state;

The first heat storage unit and the second heat storage unit are used to store compression heat generated by the first stage compression;

The third heat storage unit is used to store compression heat generated by the second stage compression;

The first heat storage unit comprises: a first heat exchanger 11, a first hot storage tank 12, a sixth heat exchanger 13, and a first cold storage tank 14; the outlet of the first cold storage tank 14 is connected to the inlet of the first hot storage tank 12 through the cold side channel of the first heat exchanger 11, and the outlet of the first hot storage tank 12 is connected to the inlet of the first cold storage tank 14 through the hot side channel of the sixth heat exchanger 13;

The second heat storage unit comprises: a second heat exchanger 15, a second hot storage tank 16, a fifth heat exchanger 17, and a second cold storage tank; the outlet of the second cold storage tank 18 is connected to the inlet of the second hot storage tank 16 through the cold side channel of the second heat exchanger 15, and the outlet of the second hot storage tank 16 is connected to the inlet of the second cold storage tank 18 through the hot side channel of the fifth heat exchanger 17;

The third heat storage unit comprises: a third heat exchanger 19, a third hot storage tank, a fourth heat exchanger, and a third cold storage tank; the outlet of the third cold storage tank 22 is connected to the inlet of the third hot storage tank 20 through the cold side channel of the third heat exchanger 19, and the outlet of the third hot storage tank 20 is connected to the inlet of the third cold storage tank 22 through the hot side channel of the fourth heat exchanger 21;

The liquefaction unit includes: a condenser 4, a fourth hot storage tank 23, an evaporator 7, and a fourth cold storage tank 24; the hot side channel inlet of the condenser 4 is connected to the hot side channel outlet of the third heat exchanger 19, and the outlet is connected to the inlet of the liquid _CO2 storage tank 6 through a valve 5; the saturated gaseous carbon dioxide released from the outlet of the valve 5 enters the inlet of the second compressor 3 through the return air; the cold side channel inlet of the evaporator 7 is connected to the outlet of the liquid _CO2 storage tank 6, and the outlet is connected to the cold side channel inlet of the fourth heat exchanger 21.

The high-temperature compressed carbon dioxide energy storage system provided by the utility model adopts a high-pressure-ratio-high-temperature compression scheme, which greatly increases the work per unit mass of carbon dioxide and effectively reduces the volume of the flexible gas storage bag. At the same time, the high-pressure carbon dioxide adopts self-condensation circulation technology and does not require an additional cold source from the outside. The efficiency of the energy storage system is improved and the investment cost is reduced.

In an optional embodiment of the utility model, the gas storage bag 1 is composed of a flexible air bag, the volume of which changes with the amount of gas stored, so that the carbon dioxide inside is always stored at ambient pressure;

Optionally, in the embodiment of the utility model, the first compressor 2 is a high pressure ratio compressor, and the outlet temperature is a high temperature that can reach 450-550° C., which can effectively improve the work capacity of a unit working fluid.

Optionally, in the embodiment of the utility model, each hot storage tank and each cold storage tank outlet is provided with a circulation pump (not shown in the figure).

Optionally, in the embodiment of the utility model, the heat storage medium stored in the first hot storage tank 12 and the first cold storage tank 14 is molten salt; the heat storage medium stored in the second hot storage tank 16, the second cold storage tank 18, the third hot storage tank 20, the third cold storage tank 22, the fourth hot storage tank 23, and the fourth cold storage tank 24 is liquid water.

The utility model provides a high-temperature compressed carbon dioxide energy storage system, which compresses carbon dioxide in an ambient state to a high-temperature and high-pressure state with a high-pressure ratio, uses molten salt as a high-temperature heat storage medium to store heat, and uses pressurized water as a low-temperature heat storage medium to store heat, thereby improving the work capacity per unit mass of the working fluid and reducing the volume of the gas storage bag; the utility model provides a high-temperature compressed carbon dioxide energy storage system, and the high-pressure carbon dioxide liquefaction adopts a self-condensing cycle, does not require an additional cold source, improves the system efficiency, and reduces the system operation cost. Exemplarily, the utility model can be applied to the fields of renewable energy utilization, power grid peak regulation, etc.

In addition, the utility model provides an operating method of a high temperature compressed carbon dioxide energy storage system, comprising the following steps:

Charging process: At the beginning of the charging process, the low-pressure carbon dioxide in the gas storage bag 1 enters the compression unit and is first compressed to a high temperature state (450-550°C) in the first compressor 2; the compression heat is released to the heat storage medium from the first cold storage tank 14 in the first heat exchanger 11, and the high-temperature heat storage medium after absorbing heat is stored in the first heat storage tank 12; the remaining compression heat is released to the heat storage medium from the second cold storage tank 18 in the second heat exchanger 15, and the heat storage medium after absorbing heat is stored in the second heat storage tank 16; the carbon dioxide in the high-pressure and low-temperature state is mixed with the heat storage medium in the return gas. The carbon dioxide is mixed and compressed to a supercritical state in the second compressor 3; the compression heat is released to the heat storage medium from the third cold storage tank 22 in the third heat exchanger 19, and the heat storage medium after absorbing heat is stored in the third heat storage tank 20; it is then condensed into a liquid in the condenser 4, and the released heat in the condensation process is absorbed by the water from the fourth cold storage tank 24 and stored in the fourth heat storage tank 23; then, the liquefied carbon dioxide flows through the valve 5 for throttling, and the saturated gaseous carbon dioxide therein flows back to the second compressor 3 through the return gas, and the liquid carbon dioxide is stored in the liquid _CO2 storage tank 6, and the charging process is completed.

Discharge process: the carbon dioxide liquid released from the liquid _CO2 storage tank 6 is heated and evaporated in the evaporator 7 by the heat storage medium from the fourth heat storage tank 23, and the cooled heat storage medium is stored in the fourth cold storage tank 24; the high-pressure gaseous carbon dioxide released from the evaporator 7 is heated in the fourth heat exchanger 21 by the heat storage medium from the third heat accumulator 20, and then enters the first expander 8 to expand and generate electricity; the generated exhaust steam is continuously heated in the fifth heat exchanger 17 and the sixth heat exchanger 13, and enters the second expander 9 to expand and generate electricity; then the low-pressure carbon dioxide enters the radiator 10, is cooled to ambient temperature and stored in the gas storage bag 1, and the discharge process ends.

The advantages of the operating method of the high-temperature compressed carbon dioxide energy storage system over the prior art are the same as those of the high-temperature compressed carbon dioxide energy storage system, which will not be repeated here.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the utility model can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the utility model should be included in the scope of protection of the claims of the utility model.

Claims (4)

1. A high-temperature compressed carbon dioxide energy storage system, characterized in that it comprises: a gas storage bag (1), a first compressor (2), a first heat storage unit, a second heat storage unit, a second compressor (3), a third heat storage unit, a liquefaction unit, a valve (5), a liquid _CO2 storage tank (6), a first expander (8), a second expander (9), and a radiator (10); the gas storage bag (1) is connected to the first compressor (2), the first heat storage unit, the second heat storage unit, the second compressor (3), the third heat storage unit, the liquefaction unit, the valve (5), and the liquid _CO2 storage tank (6) in sequence; the liquid _CO2 storage tank (6), the liquefaction unit, the third heat storage unit, the first expander (8), the second heat storage unit, the first heat storage unit, the second expander (9), the radiator (10), and the gas storage bag (1) are connected in sequence; The first compressor compresses the carbon dioxide to a supercritical state; The first heat storage unit and the second heat storage unit are used to store compression heat generated by the first stage compression; The third heat storage unit is used to store compression heat generated by the second stage compression; The first heat storage unit comprises: a first heat exchanger (11), a first hot storage tank (12), a sixth heat exchanger (13), and a first cold storage tank (14); the outlet of the first cold storage tank (14) is connected to the inlet of the first hot storage tank (12) through a cold side channel of the first heat exchanger (11), and the outlet of the first hot storage tank (12) is connected to the inlet of the first cold storage tank (14) through a hot side channel of the sixth heat exchanger (13); The second heat storage unit comprises: a second heat exchanger (15), a second hot storage tank (16), a fifth heat exchanger (17), and a second cold storage tank; the outlet of the second cold storage tank (18) is connected to the inlet of the second hot storage tank (16) through the cold side channel of the second heat exchanger (15), and the outlet of the second hot storage tank (16) is connected to the inlet of the second cold storage tank (18) through the hot side channel of the fifth heat exchanger (17); The third heat storage unit comprises: a third heat exchanger (19), a third hot storage tank (20), a fourth heat exchanger (21), and a third cold storage tank (22); the outlet of the third cold storage tank (22) is connected to the inlet of the third hot storage tank (20) through a cold side channel of the third heat exchanger (19), and the outlet of the third hot storage tank (20) is connected to the inlet of the third cold storage tank (22) through a hot side channel of the fourth heat exchanger (21); The liquefaction unit comprises: a condenser (4), a fourth hot storage tank (23), an evaporator (7), and a fourth cold storage tank (24); the hot side channel inlet of the condenser (4) is connected to the hot side channel outlet of the third heat exchanger (19), and the outlet is connected to the inlet of the liquid _CO2 storage tank (6) through a valve (5); the saturated gaseous carbon dioxide released from the outlet of the valve (5) enters the inlet of the second compressor (3) through the return air; the cold side channel inlet of the evaporator (7) is connected to the outlet of the liquid _CO2 storage tank (6), and the outlet is connected to the cold side channel inlet of the fourth heat exchanger (21). 2. A high-temperature compressed carbon dioxide energy storage system according to claim 1, characterized in that the gas storage bag (1) is composed of a flexible air bag, the volume of which changes momentarily with the amount of gas stored, so that the carbon dioxide inside is always stored at ambient pressure. 3. A high-temperature compressed carbon dioxide energy storage system according to claim 1, characterized in that the first compressor (2) is a high-pressure ratio compression, and the outlet temperature is a high temperature that can reach 450-550°C, which can effectively improve the work capacity of the unit working fluid. 4. A high-temperature compressed carbon dioxide energy storage system according to claim 1, characterized in that the heat storage medium stored in the first hot storage tank (12) and the first cold storage tank (14) is molten salt; the heat storage medium stored in the second hot storage tank (16), the second cold storage tank (18), the third hot storage tank (20), the third cold storage tank (22), the fourth hot storage tank (23), and the fourth cold storage tank (24) is liquid water.