A carbon dioxide power generation device and a working method thereof

Abstract

The present invention discloses a carbon dioxide power generation device and a working method thereof, comprising a focusing tower, a molten salt heat exchanger, a carbon dioxide turbine and a regenerator; the focusing tower is connected to the first heat exchange side of the molten salt heat exchanger to form a loop back to the focusing tower, and the heat exchange medium of the first heat exchange side of the molten salt heat exchanger adopts molten salt; the heat exchange medium of the second heat exchange side of the molten salt heat exchanger adopts high-pressure carbon dioxide fluid, and the outlet of the second heat exchange side of the molten salt heat exchanger is sequentially connected to the inlet of the carbon dioxide turbine, the regenerator and the second heat exchange side of the molten salt heat exchanger to form a loop. It can combine supercritical carbon dioxide with solar power generation, with high power generation efficiency, and realize green and efficient power generation.

Description

Technical Field

[0001] The present invention belongs to the field of photothermal power generation and relates to a carbon dioxide power generation device and a working method thereof. Background Art

[0002] With the introduction of carbon peak and carbon neutrality policies, new energy sources such as solar energy will become the main form of future energy structure. Supercritical carbon dioxide power generation has the characteristics of good matching and excellent efficiency, showing great potential and broad application prospects in solar thermal power generation, but there is currently no technology that combines supercritical carbon dioxide with solar power generation. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a carbon dioxide power generation device and a working method thereof, which can combine supercritical carbon dioxide with solar power generation, have high power generation efficiency, and realize green and efficient power generation.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A carbon dioxide power generation device comprises a focusing tower, a molten salt heat exchanger, a carbon dioxide turbine and a regenerator;

[0006] The focusing tower is connected to the first heat exchange side of the molten salt heat exchanger to form a loop back to the focusing tower. The heat exchange medium of the first heat exchange side of the molten salt heat exchanger is molten salt; the heat exchange medium of the second heat exchange side of the molten salt heat exchanger is high-pressure carbon dioxide fluid. The outlet of the second heat exchange side of the molten salt heat exchanger is connected to the carbon dioxide turbine, the regenerator and the inlet of the second heat exchange side of the molten salt heat exchanger in sequence to form a loop.

[0007] Preferably, the first heat exchange side inlet of the regenerator is connected to the carbon dioxide turbine outlet, the second heat exchange side outlet of the regenerator is connected to the second heat exchange side inlet of the molten salt heat exchanger, and the first heat exchange side outlet of the regenerator is sequentially connected to the first heat exchange side of the generator, the first heat exchange side of the evaporator, the carbon dioxide compressor and the second heat exchange side inlet of the regenerator.

[0008] Furthermore, the condensing side of the condenser is connected between the second heat exchange side of the generator and the second heat exchange side of the evaporator, and the heat absorption side of the condenser is connected to the heat network water supply.

[0009] Furthermore, the medium in the second heat exchange side of the generator is a salt solution.

[0010] Furthermore, a solvent throttle valve is connected between the condensation side of the condenser and the second heat exchange side of the evaporator.

[0011] Furthermore, the second heat exchange side outlet of the evaporator is connected to the heat release side inlet of the absorber, the heat absorption side inlet of the absorber is connected to the heat network return water, and the heat absorption side outlet of the absorber is connected to the heat absorption side inlet of the condenser.

[0012] Furthermore, the second heat exchange side outlet of the generator is connected to the first heat exchange side inlet of the solution heat exchanger, the first heat exchange side outlet of the solution heat exchanger is connected to the heat release side inlet of the absorber, the heat release side outlet of the absorber is connected to the second heat exchange side inlet of the solution heat exchanger, and the second heat exchange side outlet of the solution heat exchanger is connected to the first heat exchange side inlet of the generator.

[0013] Furthermore, a solution expansion valve is provided between the first heat exchange side outlet of the solution heat exchanger and the heat release side inlet of the absorber, and a solution pump is provided between the heat release side outlet of the absorber and the second heat exchange side inlet of the solution heat exchanger.

[0014] A working method of the carbon dioxide power generation device according to any one of the above, comprising the following process:

[0015] The concentrating tower absorbs solar energy and heats the molten salt in the tower, making the temperature of the molten salt reach above 600℃. The molten salt enters the first heat exchange side of the molten salt heat exchanger from the concentrating tower, heats the high-pressure carbon dioxide fluid on the second heat exchange side of the molten salt heat exchanger. After being heated, the high-pressure carbon dioxide fluid enters the carbon dioxide turbine to do work, and then enters the regenerator. The high-pressure carbon dioxide fluid from the regenerator absorbs heat on the second heat exchange side of the molten salt heat exchanger.

[0016] Preferably, after the high-pressure carbon dioxide fluid on the first heat exchange side of the regenerator is cooled, it enters the generator, heats the salt solution in the second heat exchange side of the generator, causes the solvent in the salt solution to evaporate due to the heat, increases the concentration of the solution, and the carbon dioxide itself is cooled once; the carbon dioxide after the primary cooling enters the first heat exchange side of the evaporator, exchanges heat with the low-pressure condensed water on the second heat exchange side of the evaporator, the low-pressure condensed water is heated and evaporated into water vapor, and the carbon dioxide itself is cooled for a second time; the carbon dioxide after the secondary cooling enters the carbon dioxide compressor from the evaporator, is pressurized, and enters the second heat exchange side of the regenerator for heat exchange with the high-temperature carbon dioxide on the first heat exchange side of the regenerator.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention adopts a focusing tower to absorb solar energy and heat the molten salt in the molten salt heat exchanger. The heated molten salt is used to heat the high-pressure carbon dioxide fluid. The high-pressure carbon dioxide fluid enters the carbon dioxide turbine to do work, and then goes to the regenerator for cooling, and finally returns to the molten salt heat exchanger. Supercritical carbon dioxide can be combined with solar power generation to realize the conversion of high-grade thermal energy into electrical energy, with high power generation efficiency, thereby realizing green and efficient power generation.

[0019] Furthermore, by utilizing the phase change heat absorption characteristics of the generator and evaporator in the absorption heat pump, the cascade utilization of carbon dioxide waste heat can be achieved, while avoiding the problem of deterioration of heat transfer at the pinch point inside the molten salt heat exchanger during direct heat exchange.

[0020] Furthermore, the cooling of the carbon dioxide before the inlet of the carbon dioxide compressor is achieved by the phase change process of the solvent in the evaporator, which is beneficial to controlling the temperature of the carbon dioxide near the critical point to be constant and has certain significance for the stability of the power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Among them: 1- focusing tower; 2- molten salt heat exchanger; 3- carbon dioxide turbine; 4- regenerator; 5- carbon dioxide compressor; 6- generator; 7- condenser; 8- evaporator; 9- absorber; 10- solution heat exchanger; 11- solution expansion valve; 12- solution pump; 13- solvent throttle valve. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0024] like Figure 1 As shown, the carbon dioxide power generation device of the present invention includes a focusing tower 1, a molten salt heat exchanger 2, a carbon dioxide turbine 3, a regenerator 4, a carbon dioxide compressor 5, a generator 6, a condenser 7, an evaporator 8, an absorber 9, a solution heat exchanger 10, a solution expansion valve 11, a solution pump 12, and a solvent throttle valve 13.

[0025] The focusing tower 1 is connected to the first heat exchange side of the molten salt heat exchanger 2 to form a loop back to the focusing tower 1. The heat exchange medium of the first heat exchange side of the molten salt heat exchanger 2 is molten salt; the heat exchange medium of the second heat exchange side of the molten salt heat exchanger 2 is high-pressure carbon dioxide fluid, and the outlet of the second heat exchange side of the molten salt heat exchanger 2 is connected to the carbon dioxide turbine 3, the regenerator 4 and the inlet of the second heat exchange side of the molten salt heat exchanger 2 in sequence to form a loop.

[0026] The first heat exchange side inlet of the regenerator 4 is connected to the outlet of the carbon dioxide turbine 3, the second heat exchange side outlet of the regenerator 4 is connected to the inlet of the second heat exchange side of the molten salt heat exchanger 2, and the first heat exchange side outlet of the regenerator 4 is sequentially connected to the first heat exchange side of the generator 6, the first heat exchange side of the evaporator 8, the carbon dioxide compressor 5 and the second heat exchange side inlet of the regenerator 4.

[0027] The medium in the second heat exchange side of the generator 6 is a salt solution, the condensation side of the condenser 7 is connected between the second heat exchange side of the generator 6 and the second heat exchange side of the evaporator 8, and the heat absorption side of the condenser 7 is connected to the water supply of the heat network. A solvent throttle valve 13 is connected between the condensation side of the condenser 7 and the second heat exchange side of the evaporator 8. The outlet of the second heat exchange side of the evaporator 8 is connected to the inlet of the heat release side of the absorber 9, the inlet of the heat absorption side of the absorber 9 is connected to the return water of the heat network, and the outlet of the heat absorption side of the absorber 9 is connected to the inlet of the heat absorption side of the condenser 7.

[0028] The second heat exchange side outlet of the generator 6 is connected to the first heat exchange side inlet of the solution heat exchanger 10, the first heat exchange side outlet of the solution heat exchanger 10 is connected to the exothermic side inlet of the absorber 9, the exothermic side outlet of the absorber 9 is connected to the second heat exchange side inlet of the solution heat exchanger 10, and the second heat exchange side outlet of the solution heat exchanger 10 is connected to the first heat exchange side inlet of the generator 6.

[0029] A solution expansion valve 11 is provided between the first heat exchange side outlet of the solution heat exchanger 10 and the heat release side inlet of the absorber 9 , and a solution pump 12 is provided between the heat release side outlet of the absorber 9 and the second heat exchange side inlet of the solution heat exchanger 10 .

[0030] The working method of the carbon dioxide power generation device of the present invention comprises the following process:

[0031] The concentrating tower 1 absorbs solar energy and heats the molten salt in the tower, so that the temperature of the molten salt reaches above 600° C. The molten salt enters the first heat exchange side of the molten salt heat exchanger 2 from the concentrating tower 1 and heats the high-pressure carbon dioxide fluid on the second heat exchange side of the molten salt heat exchanger 2.

[0032] The high-pressure carbon dioxide fluid from the second heat exchange side of the regenerator 4 absorbs heat on the second heat exchange side of the molten salt heat exchanger 2, enters the carbon dioxide turbine 3 to do work, and then returns to the first heat exchange side of the regenerator 4 to exchange heat with the low-temperature carbon dioxide on the second heat exchange side of the regenerator 4, and the temperature drops to about 110°C; the carbon dioxide on the first heat exchange side of the regenerator 4 continues to enter the first heat exchange side of the generator 6, heating the salt solution in the second heat exchange side of the generator 6, so that the solvent in the salt solution evaporates due to heat, the concentration of the solution increases, and the carbon dioxide itself is cooled once, and the temperature reaches 50°C~ 60℃; the carbon dioxide after primary cooling continues to enter the first heat exchange side of the evaporator 8, and exchanges heat with the low-pressure condensed water on the other side. The low-pressure condensed water is heated and evaporated into water vapor, and the carbon dioxide itself is secondary cooled, and the temperature reaches the critical temperature of 35℃; the carbon dioxide after secondary cooling enters the carbon dioxide compressor 5 from the first heat exchange side of the evaporator 8, and after being pressurized, enters the second heat exchange side of the regenerator 4 to exchange heat with the high-temperature carbon dioxide on the first heat exchange side of the regenerator 4, and then enters the second heat exchange side of the molten salt heat exchanger 2, forming a carbon dioxide power generation cycle. This part realizes the conversion of solar energy into electrical energy through the circulation of carbon dioxide working fluid.

[0033] The waste heat utilization of carbon dioxide is mainly realized by a closed absorption heat pump composed of a generator 6, a condenser 7, an evaporator 8, an absorber 9 and a solution heat exchanger 10. In the second heat exchange side of the generator 6, the salt solution composed of salt and solvent is heated by the high-temperature section of carbon dioxide, the solvent in the solution evaporates, and the concentration of the solution increases. Among them, the evaporated solvent enters the condensation side of the condenser 7 and condenses into liquid, and the released heat is absorbed by the hot network water; after the condensed solvent is throttled by the solvent throttle valve 13, due to the pressure reduction, the corresponding saturation temperature is reduced, and the solvent itself approaches the saturation point and enters the second heat exchange side of the evaporator 8. In the second heat exchange side of the evaporator 8, it is further heated by the low-temperature section of carbon dioxide, evaporates into gas, and enters the heat release side of the absorber 9.

[0034] The concentrated solution produced by the heating and evaporation at the second heat exchange side of the generator 6 first enters the first heat exchange side of the solution heat exchanger 10, exchanges heat with the dilute solution delivered by the solution pump 12, and then enters the heat release side of the absorber 9 after being throttled by the solution expansion valve 11. The concentrated solution in the heat release side of the absorber 9 absorbs the low-pressure water vapor from the second heat exchange side of the evaporator 8, releasing latent heat and heat of solution. The hot network water first enters the heat absorption side of the absorber 9 for primary heating, and then enters the heat absorption side of the condenser 7 for secondary heating, realizing the recovery and utilization of waste heat in the carbon dioxide power generation process.

[0035] On the one hand, supercritical carbon dioxide is used to generate electricity, making full use of the high-quality thermal energy of tower solar energy; on the other hand, absorption heat pump technology is used to make step-by-step use of the waste heat in the supercritical carbon dioxide cooling process. On the basis of meeting the water supply temperature of the heating network, the deterioration of heat transfer in the heat exchanger is avoided, thus achieving a deeper level of utilization of solar energy.

[0036] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A carbon dioxide power generation device, characterized in that: It comprises a focusing tower (1), a molten salt heat exchanger (2), a carbon dioxide turbine (3) and a regenerator (4); The focusing tower (1) is connected to the first heat exchange side of the molten salt heat exchanger (2) to form a loop back to the focusing tower (1), and the heat exchange medium of the first heat exchange side of the molten salt heat exchanger (2) is molten salt; the heat exchange medium of the second heat exchange side of the molten salt heat exchanger (2) is high-pressure carbon dioxide fluid, and the outlet of the second heat exchange side of the molten salt heat exchanger (2) is connected to the carbon dioxide turbine (3), the regenerator (4) and the inlet of the second heat exchange side of the molten salt heat exchanger (2) in sequence to form a loop; The first heat exchange side inlet of the regenerator (4) is connected to the outlet of the carbon dioxide turbine (3), the second heat exchange side outlet of the regenerator (4) is connected to the second heat exchange side inlet of the molten salt heat exchanger (2), and the first heat exchange side outlet of the regenerator (4) is sequentially connected to the first heat exchange side of the generator (6), the first heat exchange side of the evaporator (8), the carbon dioxide compressor (5), and the second heat exchange side inlet of the regenerator (4); The condensing side of the condenser (7) is connected between the second heat exchange side of the generator (6) and the second heat exchange side of the evaporator (8), and the heat absorption side of the condenser (7) is connected to a heat network water supply; A solvent throttle valve (13) is connected between the condensation side of the condenser (7) and the second heat exchange side of the evaporator (8); The second heat exchange side outlet of the evaporator (8) is connected to the heat release side inlet of the absorber (9), the heat absorption side inlet of the absorber (9) is connected to the heat network return water, and the heat absorption side outlet of the absorber (9) is connected to the heat absorption side inlet of the condenser (7); The second heat exchange side outlet of the generator (6) is connected to the first heat exchange side inlet of the solution heat exchanger (10), the first heat exchange side outlet of the solution heat exchanger (10) is connected to the heat release side inlet of the absorber (9), the heat release side outlet of the absorber (9) is connected to the second heat exchange side inlet of the solution heat exchanger (10), and the second heat exchange side outlet of the solution heat exchanger (10) is connected to the first heat exchange side inlet of the generator (6); A solution expansion valve (11) is provided between the first heat exchange side outlet of the solution heat exchanger (10) and the heat release side inlet of the absorber (9), and a solution pump (12) is provided between the heat release side outlet of the absorber (9) and the second heat exchange side inlet of the solution heat exchanger (10).

2. The carbon dioxide power generation device according to claim 1, characterized in that: The medium in the second heat exchange side of the generator (6) is a salt solution.

3. A working method of the carbon dioxide power generation device according to any one of claims 1-2, characterized in that: The process includes: The focusing tower (1) absorbs solar energy and heats the molten salt in the tower, so that the temperature of the molten salt reaches above 600°C. The molten salt enters the first heat exchange side of the molten salt heat exchanger (2) from the focusing tower (1), heats the high-pressure carbon dioxide fluid on the second heat exchange side of the molten salt heat exchanger (2), and after being heated, the high-pressure carbon dioxide fluid enters the carbon dioxide turbine (3) to perform work, and then enters the regenerator (4). The high-pressure carbon dioxide fluid from the regenerator (4) absorbs heat on the second heat exchange side of the molten salt heat exchanger (2).

4. The working method of the carbon dioxide power generation device according to claim 3, characterized in that: After the high-pressure carbon dioxide fluid on the first heat exchange side of the regenerator (4) is cooled, it enters the generator (6) and heats the salt solution in the second heat exchange side of the generator (6), causing the solvent in the salt solution to evaporate due to the heat, thereby increasing the concentration of the solution and cooling the carbon dioxide itself once; the carbon dioxide after the primary cooling enters the first heat exchange side of the evaporator (8) and exchanges heat with the low-pressure condensed water on the second heat exchange side of the evaporator (8), the low-pressure condensed water is heated and evaporated into water vapor, and the carbon dioxide itself is cooled for a second time; the carbon dioxide after the secondary cooling enters the carbon dioxide compressor (5) from the evaporator (8), is pressurized, and then enters the second heat exchange side of the regenerator (4) and exchanges heat with the high-temperature carbon dioxide on the first heat exchange side of the regenerator (4).

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