Method and system of high-temperature calcium looping thermochemical energy storage

Abstract

A method and a system of a high-temperature calcium looping thermochemical energy storage are provided. A thermochemical energy storage system is based on CaCO.sub.3/CaO, and an energy storage is performed by a mutual transformation between a thermal energy and a chemical energy. When solar irradiation is sufficient, CaCO.sub.3 solid particulates are indirectly heated by hot air generated from solar energy to perform an endothermic decomposition reaction, and received heat is stored in decomposition products of CaO and CO.sub.2 in a form of the chemical energy. When heat is required, a reversible thermochemical reaction occurs between the CaO and CO.sub.2 under an atmospheric pressure, and the chemical energy stored in the CaO and CO.sub.2 is transformed into the heat for release.

Claims

1. A high-temperature calcium looping thermochemical energy storage system, comprising: a solar energy heat collecting device, an energy storage device, and a power generation device; wherein the solar energy heat collecting device comprises a heliostat, a solar energy absorption tower, a first heat exchanger, and a cold air storage tank; the heliostat is provided on a side of the solar energy absorption tower; the solar energy absorption tower is configured to absorb sunlight reflected by the heliostat; the solar energy absorption tower, the first heat exchanger and the cold air storage tank are sequentially connected by using first circulation pipelines; the energy storage device comprises a first powder heat exchanger, a reactor, a second powder heat exchanger, a high-temperature CaO storage tank, a high-temperature CaCO.sub.3 storage tank, a mill, a first compressor, a CO.sub.2 storage tank, and a first gate valve; an outlet of the CO.sub.2 storage tank is provided with two CO.sub.2 circulation pipelines, a first CO.sub.2 circulation pipeline of the two CO.sub.2 circulation pipelines is configured for sequential connections of an outlet of the CO.sub.2 storage tank, the first heat exchanger, the first gate valve, the reactor, the first powder heat exchanger, the first compressor, an inlet of the CO.sub.2 storage tank, and a second CO.sub.2 circulation pipeline of the two CO.sub.2 circulation pipelines is configured for sequential connections of the outlet of the CO.sub.2 storage tank, the second powder heat exchanger, the first gate valve, the reactor, the first powder heat exchanger, the first compressor, and the inlet of the CO.sub.2 storage tank; a solid particulate material inlet of the reactor is connected to the high-temperature CaCO.sub.3 storage tank, and the first powder heat exchanger and the mill are sequentially provided between first connection pipelines; a solid particulate material outlet of the reactor is connected to the high-temperature CaO storage tank, and the second powder heat exchanger is provided between second connection pipelines; and the power generation device comprises the first powder heat exchanger, the reactor, the second powder heat exchange, the high-temperature CaO storage tank, the high-temperature CaCO.sub.3 storage tank, and the CO.sub.2 storage tank, a turbine, a condenser, a second compressor, an expander, a second gate valve, the first gate valve; a gas outlet of the reactor, the turbine, the second powder heat exchanger, the condenser, the second compressor, the first gate valve, a heating device, the first gate valve, a gas inlet of the reactor are sequentially connected by using second circulation pipelines; the CO.sub.2 storage tank and a gas inlet of the expander are connected to each other, and the second powder heat exchanger is provided between third connection pipelines; a gas outlet of the expander and the reactor are connected to each other, and the heating device is provided between fourth connection pipelines; the solid particulate material inlet of the reactor is connected to the high-temperature CaO storage tank, and the first powder heat exchanger is provided between fifth connection pipelines; and the solid particulate material outlet of the reactor is connected to the high-temperature CaCO.sub.3 storage tank, and the second powder heat exchanger is provided between sixth connection pipelines.

2. The high-temperature calcium looping thermochemical energy storage system according to claim 1, wherein the heating device comprises a heater, a third gate valve, and a fourth gate valve; the heater is connected to the third gate valve; and the fourth gate valve is respectively connected to the heater and the third gate valve in parallel.

3. The high-temperature calcium looping thermochemical energy storage system according to claim 2, wherein the reactor is a bidirectional high-temperature vibrating fluidized bed reactor; and a high-temperature resistant conveyor is provided inside the reactor.

4. The high-temperature calcium looping thermochemical energy storage system according to claim 3, wherein the bidirectional high-temperature vibrating fluidized bed reactor is made of Inconel 617 material.

5. The high-temperature calcium looping thermochemical energy storage system according to claim 1, wherein the reactor is a bidirectional high-temperature vibrating fluidized bed reactor; and a high-temperature resistant conveyor is provided inside the reactor.

6. The high-temperature calcium looping thermochemical energy storage system according to claim 5, wherein the bidirectional high-temperature vibrating fluidized bed reactor is made of Inconel 617 material.

7. A high-temperature calcium looping thermochemical energy storage method, wherein a thermochemical energy storage system is based on CaCO.sub.3/CaO, and an energy storage is performed by a mutual transformation between a thermal energy and a chemical energy; wherein the method comprises: when solar irradiation is sufficient, performing an endothermic decomposition reaction on CaCO.sub.3 solid particulates after the CaCO.sub.3 solid particulates are indirectly heated by hot air generated from solar energy, storing received heat in decomposition products of CaO and CO.sub.2 in a form of the chemical energy; wherein when heat is required, a reversible thermochemical reaction occurs between the CaO and the CO.sub.2 under an atmospheric pressure, and the chemical energy stored in the CaO and the CO.sub.2 is transformed into the heat for release, the method further comprising an energy storage stage and an energy release stage; wherein in the energy storage stage, original CO.sub.2 exchanges heat with high-temperature hot air absorbing the solar energy in a first heat exchanger and CaCO.sub.3 solid particulates reach a reaction temperature and a fluidization state in a bidirectional high-temperature vibrating fluidized bed reactor; the CaCO.sub.3 solid particulates are subjected to a decomposition reaction at a reaction temperature of 900-1100° C.; proceeding an energy storage reaction process, reaction waste heat of product CO.sub.2 generated by decomposing the CaCO.sub.3 solid particulates is configured to preheat subsequently reacted CaCO.sub.3 solid particulates in a first powder heat exchanger; reaction waste heat of product CaO generated by decomposing the CaCO.sub.3 solid particulates in a second powder heat exchanger is configured to preheat CO.sub.2 in a CO.sub.2 storage tank; and in the energy release stage, the CO.sub.2 reacts with CaO solid particulates to form CaCO.sub.3 solid particulates at a reaction temperature of 500-700° C., and release a large amount of heat; at this time, the CO.sub.2 is in a supercritical state, and cooperates with a Rankine Cycle and a Brayton Cycle to realize a power generation.

8. The high-temperature calcium looping thermochemical energy storage method according to claim 7, wherein the CaCO.sub.3 solid particulates and the CaO solid particulates are transported by a spiral feeding to prevent a leakage of the CO.sub.2 gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of an overall workflow of a system of the present invention;

(2) FIG. 2 is a schematic diagram showing an energy storage in a workflow of a system of the present invention; and

(3) FIG. 3 is a schematic diagram showing an energy release in a workflow of a system of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(4) In order to deeply understand the present invention, the present invention will be further described with reference to the embodiment and the drawings. The embodiment is merely used for illustrating the present invention and forms no limitation to the protection scope of the present invention.

Embodiment 1

(5) As shown in FIG. 1, a high-temperature calcium looping thermochemical energy storage system includes the solar energy heat collecting device, the energy storage device and power generation device.

(6) The solar energy heat collecting device includes the heliostat (1), the solar energy absorption tower (2), the heat exchanger A (3) and the cold air storage tank (4). The heliostat (1) is provided on a side of the solar energy absorption tower (2), so that sunlight reflected by the heliostat (1) can be absorbed by the solar energy absorption tower (2). The solar energy absorption tower (2), the heat exchanger A (3) and the cold air storage tank (4) are sequentially connected by using circulation pipelines.

(7) The energy storage device includes the powder heat exchanger B (5), the high-temperature vibrating fluidized bed reactor (6), the powder heat exchanger C (7), the high-temperature CaO storage tank (8), the high-temperature CaCO.sub.3 storage tank (9), the mill (10), the compressor A (11), the CO.sub.2 storage tank (12) and the gate valve B (18). An outlet of the CO.sub.2 storage tank (12) is provided with two CO.sub.2 circulation pipelines. A first CO.sub.2 circulation pipeline of the two CO.sub.2 circulation pipelines is configured for sequential connections of the outlet of the CO.sub.2 storage tank (12), the heat exchanger A (3), the gate valve B (18), the high-temperature vibrating fluidized bed reactor (6), the powder heat exchanger B (5), the compressor A (11), an inlet of the CO.sub.2 storage tank (12). A second CO.sub.2 circulation pipeline of the two CO.sub.2 circulation pipelines is configured for sequential connections of the outlet of the CO.sub.2 storage tank (12), the powder heat exchanger C (7), the gate valve B (18), the high-temperature vibrating fluidized bed reactor (6), the powder heat exchanger B (5), the compressor A (11), and the inlet of the CO.sub.2 storage tank (12). A solid particulate material inlet of the high-temperature vibrating fluidized bed reactor (6) is connected to the high-temperature CaCO.sub.3 storage tanks (9), and the powder heat exchanger B (5) and the mill (10) are sequentially provided between the connection pipelines. A solid particulate material outlet of the high-temperature vibrating fluidized bed reactor (6) is connected to the high-temperature CaO storage tank (8), and the powder heat exchanger C (7) is provided between the connection pipelines.

(8) The power generation device includes the powder heat exchanger B (5), the high-temperature vibrating fluidized bed reactor (6), the powder heat exchanger C (7), the high-temperature CaO storage tank (8), the high-temperature CaCO.sub.3 storage tank (9), and the CO.sub.2 storage tank (12), the turbine (13), the condenser (14), the compressor B (15), the expander (16), the gate valve A (17), the gate valve B (18). A gas outlet of the high-temperature vibrating fluidized bed reactor (6), the turbine (13), the powder heat exchanger B (5), the condenser (14), the compressor B (15), the gate valve A (17), a heating device, the gate valve B (18), a gas inlet of the bidirectional high-temperature vibrating fluidized bed reactor (6) are sequentially connected by using the circulation pipelines. The CO.sub.2 storage tank (12) and a gas inlet of the expander (16) are connected to each other, and the powder heat exchanger C (7) is provided between the connection pipelines. A gas outlet of the expander (16) and the high-temperature vibrating fluidized bed reactor (6) are connected to each other and the heating device is provided between the connection pipelines. The solid particulate material inlet of the high-temperature vibrating fluidized bed reactor (6) is connected to the high-temperature CaO storage tank (8) and the powder heat exchanger B (5) is provided between the connection pipelines. The solid particulate material outlet of the high-temperature vibrating fluidized bed reactor (6) is connected to the high-temperature CaCO.sub.3 storage tank (9) and the powder heat exchanger C (7) is provided between the connection pipelines.

(9) The heating device includes the heater (19), the gate valve C (20), and the gate valve D (21). The heater (19) is sequentially connected to the gate valve C (20). The gate valve D (21) is respectively connected to the heater (19) and the gate valve C (20) in parallel.

(10) The bidirectional high-temperature vibrating fluidized bed reactor is made of Inconel 617 material.

(11) The workflow of the high-temperature calcium looping thermochemical energy storage system includes is as follows.

(12) In the energy storage stage, when the solar irradiation is sufficient, as shown in FIG. 2, the sunlight passes through the heliostat (1), and the solar irradiation heat is connected via the air in the solar energy absorption tower (2). The original CO.sub.2 sufficiently exchanges the heat with the high-temperature hot air in the heat exchanger A (3). Then, the high-temperature CO.sub.2 enters the bidirectional high-temperature vibrating fluidized bed reactor (6) to fluidize the CaCO.sub.3 solid particulates to perform a decomposition reaction. As further proceeding the decomposition reaction, the decomposition product CO.sub.2 is configured to preheat the subsequent CaCO.sub.3 solid particulates in the powder heat exchanger B (5), and then compression and storage are performed by the compressor A (11). In order to make full use of the waste heat in the reaction, CO.sub.2 sufficiently exchanges the heat with the decomposition product CaO in the powder heat exchanger C (7), and then enters the bidirectional high-temperature vibrating fluidized bed reactor (6) to repeat the previous process, so as to fully utilize the heat. After passing through the heat exchanger A (3), the high-temperature hot air is stored in the cold air storage tank (4).

(13) In the energy release stage, when the solar irradiation is insufficient, as shown in FIG. 3, when the energy is released for the first time to generate the power, the gate valve C (20) is opened and the gate valve D (21) is closed. CO.sub.2 is heated to reach the reaction temperature through the expander (16) and the heater (19), then enters the bidirectional high-temperature vibrating fluidized bed reactor (6) to fluidize CaO, and a synthesis reaction occurs between the CO.sub.2 and the fluidized CaO, releasing a large amount of heat. At this time, the temperature of CO.sub.2 is greater than 31° C., and the pressure of CO.sub.2 is greater than 7 MPa. The CO.sub.2 is in a supercritical state and generate the power by the turbine (13). After CO.sub.2 passes through the turbine (13) to generate the power, the remaining heat can preheat the CaO solid particulates. After the initial energy release, the gate valve C (20) is closed, and the gate valve D (21) is opened. CO.sub.2 is preheated in the powder heat exchanger C (7) by using the waste heat of the synthetic product CaCO.sub.3 solid particulates to reach the reaction temperature, and the previous CO.sub.2 process is repeated. In the energy release process, after subjected to a heating through the powder heat exchanger C (7), and an expansion through the expander (16), the CO.sub.2 preheats the CaO solid particulates, and then enters the condenser (14) to be cooled. After entering the compressor B (15), CO.sub.2 is compressed to achieve power generation by the work of bearing.

(14) In the whole high-temperature calcium looping thermochemical energy storage system, the CaCO.sub.3 solid particulates and CaO solid particulates are transported by spiral feeding to prevent the leakage of the CO.sub.2 gas.

(15) The above description is merely a preferred embodiment of the present invention, which is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. that are made within the spirit and principle of the present invention should be contained in the protection scope of the present invention.