CN114635767A - A liquid carbon dioxide energy storage system based on the combination of ejector and vortex tube - Google Patents

Abstract

The invention discloses a liquid carbon dioxide energy storage system based on combination of an ejector and a vortex tube, which solves the problems of low cycle efficiency, low energy utilization rate and the like commonly existing in the conventional compressed carbon dioxide energy storage system. The system mainly comprises carbon dioxide energy storage and release sub-cycle and organic working medium Rankine sub-cycle, a vortex tube is introduced to separate a carbon dioxide working medium into two streams of fluids with different temperatures, an ejector is used for ejecting carbon dioxide which is not condensed in a condenser, and the organic working medium Rankine cycle is used for absorbing redundant heat and cold, so that the cascade utilization of energy is realized, the energy loss is reduced, and the cycle efficiency is greatly improved. Each part has simple structure, compactness and flexibility. The liquid carbon dioxide energy storage system provided by the invention can be used for overcoming the defects of randomness, volatility and the like of renewable energy sources, improving the grid connection and consumption level of the renewable energy sources and making a contribution to the energy conservation and emission reduction work of China.

Description

A liquid carbon dioxide energy storage system based on the combination of ejector and vortex tube

technical field

The invention belongs to the technical field of energy utilization, and particularly relates to a liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube.

Background technique

The increasing depletion of fossil energy and the issue of global warming caused by the greenhouse gas carbon dioxide have attracted more and more attention, making carbon dioxide emission reduction a major strategic issue for governments and scientific circles around the world today. From the source point of view, directly reducing or eliminating the production of carbon dioxide in the production process is an effective means to reduce carbon dioxide emissions; secondly, capturing and storing the concentrated carbon dioxide emissions is another new and efficient important way.

With the continuous advancement of energy transformation, energy storage technology has received great attention from the industry, and its development and application have become an important pillar of energy transformation. Energy storage technology involves a wide range of fields. According to the form of energy involved in the energy storage process, energy storage technology can be divided into physical energy storage and chemical energy storage. Physical energy storage includes pumped storage, compressed air energy storage, flywheel energy storage, etc.; chemical energy storage includes electric gas power plants, power fluid systems, and electric chemical plants. Among them, compressed air energy storage is considered to be a promising large-scale power storage technology, which can play an important role in power production and transmission, power grid operation, and balancing power loads. However, problems such as low energy density and low overall system efficiency have been the bottlenecks for the large-scale development of compressed energy storage technology. Compared with air, carbon dioxide has a higher airflow density, and its critical point temperature is close to normal temperature. It has good physical properties and is an energy storage medium with great development potential. possibility.

The ejector is a device that uses fluid to transmit energy and mass. It uses the jet effect of the working fluid to mix two fluids with different pressures and temperatures, and exchange energy to form a mixed fluid with intermediate pressure and temperature. The pressure of the ejected fluid can be increased without directly consuming mechanical energy, the structure of the ejector is simple, and the system for connecting with various equipments is also very simple. The vortex tube is an industrial device that can separate the working fluid into two streams of different temperatures, and is often used in refrigeration systems. When the working fluid rotates at high speed in the vortex tube, it is separated into two gaseous working fluids of high temperature and low temperature through eddy current transformation. The vortex tube has no rotating parts and has the advantages of high reliability, light weight and convenient manufacture.

A lot of creative work has been carried out on compressed carbon dioxide energy storage systems at home and abroad, but compared with compressed air energy storage technology, the energy storage technology using carbon dioxide as the energy storage medium is still in the research and development stage. Some of the current compressed carbon dioxide energy storage systems generally still lack high output power, high cycle efficiency and flexible applicability, and there is still a lot of energy waste in the process of energy storage and energy release, resulting in a low overall energy utilization rate of the system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube, aiming at the above-mentioned deficiencies of the prior art.

The present invention adopts following technical scheme to realize:

A liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube, comprising a vortex tube, a condenser, a liquid carbon dioxide storage tank, a first heat exchanger, a second heat exchanger, a first turbine, a gaseous carbon dioxide storage tank, Compressor, surge tank, regenerator, third heat exchanger, second turbine and ejector;

The inlet of the condenser is communicated with the outlet of the cold air flow of the vortex tube, the first outlet of the condenser is communicated with the inlet of the liquid carbon dioxide storage tank, and the outlet of the hot air of the vortex tube is communicated with the first inlet of the gaseous carbon dioxide storage tank;

The first inlet of the first heat exchanger is communicated with the outlet of the liquid carbon dioxide storage tank, the second outlet of the first heat exchanger is communicated with the second inlet of the second heat exchanger, and the second outlet of the second heat exchanger is communicated with the first turbine The inlet is communicated, and the outlet of the first turbine is communicated with the second inlet of the first heat exchanger;

The second inlet of the gaseous carbon dioxide storage tank is communicated with the first outlet of the first heat exchanger, the outlet of the gaseous carbon dioxide storage tank is communicated with the inlet of the compressor, the outlet of the compressor is communicated with the inlet of the surge tank, and the outlet of the surge tank is communicated with the regenerator The first inlet is communicated with, the regenerator outlet is communicated with the first inlet of the third heat exchanger, the first outlet of the third heat exchanger is communicated with the second turbine inlet, and the second turbine suction port is communicated with the working fluid of the ejector The inlet communicates with the inlet, the ejection fluid inlet communicates with the second outlet of the condenser, and the ejector outlet communicates with the second inlet of the regenerator.

A further improvement of the present invention is that a first valve is arranged between the outlet of the liquid carbon dioxide storage tank and the first inlet of the first heat exchanger.

A further improvement of the present invention is that a second valve is arranged between the outlet of the gaseous carbon dioxide storage tank and the inlet of the compressor.

A further improvement of the present invention is that a third valve is arranged between the outlet of the surge tank and the first inlet of the regenerator.

A further improvement of the present invention is that a first pump is arranged between the first valve and the first inlet of the first heat exchanger.

A further improvement of the present invention is that a second pump is arranged between the second outlet of the first heat exchanger and the second inlet of the second heat exchanger.

A further improvement of the present invention is that the organic working medium Rankine cycle working medium is R245fa, R11 or R12 working medium.

A further improvement of the present invention is that the compressor is arranged coaxially with the first turbine and the second turbine.

A further improvement of the present invention is that the hot end of the third heat exchanger adopts domestic waste heat, production waste heat or solar energy collection heat source.

A further improvement of the present invention lies in that a generator is externally connected to the first turbine, and the gaseous carbon dioxide working medium and the gaseous organic working medium can do work in the first turbine and the second turbine respectively, one part is used to drive the compressor, and the other part is used to drive the compressor. Drive the generator to generate electricity.

Compared with the prior art, the present invention at least has the following beneficial technical achievements:

(1) The system of the present invention introduces a vortex tube structure, uses the vortex tube to separate the carbon dioxide working medium after heating, and divides the carbon dioxide into two fluids: low-temperature carbon dioxide gas and high-temperature carbon dioxide gas. Compared with the conventional carbon dioxide energy storage system, the condenser only needs to condense the low-temperature carbon dioxide gas separated by part of the vortex tube, which greatly reduces the cooling capacity required by the condenser, saves energy, and improves the energy storage density of the energy storage system; , a part of the carbon dioxide working medium is directly separated into high-temperature carbon dioxide gas by the vortex tube and introduced into the gaseous carbon dioxide storage tank, which increases the temperature of the gaseous working medium before the carbon dioxide energy release process, thereby reducing the heat source heat required for heating the carbon dioxide gas. While reducing energy consumption, the system efficiency is greatly improved.

(2) The system of the present invention is introduced into the ejector structure, and part of the high-temperature carbon dioxide gas is drawn from the second turbine as the working fluid, and the uncondensed gaseous carbon dioxide in the ejection condenser is mixed into the higher temperature carbon dioxide gas after passing through the ejector. In the regenerator, the temperature of the mainstream carbon dioxide gas is increased. Compared with the traditional extraction and heat recovery cycle, the ejector structure adopted in the present invention can eject the gaseous working medium from the condenser, thereby reducing the heat load of the condenser and further reducing the required cooling capacity; The higher temperature carbon dioxide gas flowing out of the outlet of the device further increases the temperature of the working medium before heating, which reduces the heat source heat required for heating the carbon dioxide gas, thereby reducing energy consumption and improving system efficiency.

(3) The present invention adopts carbon dioxide as the working medium for storing and releasing energy. Compared with air, the airflow density of carbon dioxide is higher, and the critical point temperature is close to normal temperature. When storing energy, carbon dioxide gas is easier to liquefy, and the energy storage density is higher; when releasing energy, carbon dioxide is more powerful and the equipment is more compact, thus saving more energy.

(4) In the present invention, liquid carbon dioxide is used as a cold source to provide cold energy for the organic working medium Rankine cycle, and the high-temperature spent gas after work in the second turbine is used as a heat source to provide heat for the organic working medium Rankine cycle, so that the gaseous organic The mass expands in the first turbine to do work, which in turn drives the generator to generate electricity, supplying electricity to users during peak electricity consumption periods and relieving the pressure of power supply demand. While rationally utilizing the energy of cold source and heat source, it effectively improves the cycle efficiency and further solves the user's electricity demand.

(5) The present invention couples the vortex tube, the ejector, the compressed carbon dioxide system and the organic working medium Rankine cycle to realize the cascade utilization of energy, which can greatly improve the overall cycle efficiency of the system. At the same time, the structure of each component is simple, and the whole system has high compactness and flexibility.

Description of drawings

FIG. 1 is a schematic structural diagram of a liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube proposed by the present invention.

Figure 2 is a schematic diagram of the structure of the vortex tube.

Figure 3 is a schematic diagram of the structure of the injector.

Description of reference numbers:

1. Vortex tube; 2. Condenser; 3. Liquid carbon dioxide storage tank; 4. The first pump; 5. The first heat exchanger; 6. The second pump; 7. The second heat exchanger; 8. The first pump Flat; 9. Generator; 10. Gaseous carbon dioxide storage tank; 11. Compressor; 12. Pressure stabilization tank; 13. Regenerator; 14. Third heat exchanger; 15. Second turbine; 16. Ejector ; 17, vortex tube inlet; 18, cold air outlet; 19, hot air outlet; 20, ejection fluid inlet; 21, working fluid inlet; 22, ejector outlet; 101, first valve; 102, second valve; 103. The third valve.

Detailed ways

In order to make the objectives, technical effects and technical solutions of the embodiments of the present invention clearer, the present invention will be described in detail below with reference to the embodiments and the accompanying drawings. The protection scope of the present invention is not limited to the embodiments, and any changes made by those skilled in the art within the scope defined by the claims also belong to the protection scope of the present invention.

A liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to an embodiment of the present invention includes a carbon dioxide energy storage component, an organic working medium Rankine cycle component, a carbon dioxide energy release component, a valve, a pipeline and a pump.

The carbon dioxide energy storage component specifically includes:

The inlet of the condenser 2 is communicated with the cold airflow outlet 18 of the vortex tube 1, the first outlet of the condenser 2 is communicated with the inlet of the liquid carbon dioxide storage tank 3, and the hot airflow outlet 19 of the vortex tube 1 is communicated with the first inlet of the gaseous carbon dioxide storage tank 10.

The organic working fluid Rankine cycle component specifically includes:

The first inlet of the first heat exchanger 5 is communicated with the outlet of the liquid carbon dioxide storage tank 3, the second outlet of the first heat exchanger 5 is communicated with the second inlet of the second heat exchanger 7, and the second outlet of the second heat exchanger 7 It communicates with the inlet of the first turbine 8 , and the outlet of the first turbine 8 communicates with the second inlet of the first heat exchanger 5 .

The carbon dioxide energy release component specifically includes:

The second inlet of the gaseous carbon dioxide storage tank 10 is communicated with the first outlet of the first heat exchanger 5; The outlet of the tank 12 is communicated with the first inlet of the regenerator 13 , the outlet of the regenerator 13 is communicated with the first inlet of the third heat exchanger 14 , and the first outlet of the third heat exchanger 14 is communicated with the inlet of the second turbine 15 , the suction port of the second turbine 15 communicates with the working fluid inlet 21 of the ejector 16 , the ejection fluid inlet 20 communicates with the second outlet of the condenser 2 , and the ejector outlet 22 communicates with the second inlet of the regenerator 13 .

A first valve 101 is provided between the outlet of the liquid carbon dioxide storage tank 3 and the first inlet of the first heat exchanger 5 .

A second valve 102 is provided between the outlet of the gaseous carbon dioxide storage tank 10 and the inlet of the compressor 11 .

A third valve 103 is arranged between the outlet of the surge tank 12 and the first inlet of the regenerator 13 .

A first pump 4 is arranged between the first valve 101 and the first inlet of the first heat exchanger 5 .

A second pump 6 is arranged between the second outlet of the first heat exchanger 5 and the second inlet of the second heat exchanger 7 .

Further, the organic working fluid Rankine cycle working fluid can be selected as working fluid such as R245fa, R11, R12, or a mixture of various organic working fluids can be selected as the circulating working fluid according to the actual working conditions.

Further, the compressor 11 is arranged coaxially with the first turbine 8 and the second turbine 15 .

Further, the hot end of the third heat exchanger 14 adopts domestic waste heat, production waste heat, solar heat collection and other heat sources, making full use of existing waste heat resources and reducing energy waste.

Further, the first turbine 8 is externally connected with a generator 9, and the work done by the gaseous carbon dioxide working medium and the gaseous organic working medium in the first turbine 8 and the second turbine 15 is partly used to drive the compressor 11, and the other is used to drive the compressor 11. Part of it is used to drive the generator 9 to generate electricity, and to supply electricity to users during peak electricity consumption periods, thereby relieving the pressure of power supply demand.

Based on the above-mentioned system, the workflow of the present invention is as follows:

A liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to an embodiment of the present invention, the working process of the system is divided into a carbon dioxide energy storage process, an organic working medium Rankine cycle process and a carbon dioxide energy release process, and specifically includes the following steps:

During the carbon dioxide energy storage process, the carbon dioxide after supplying heat to the organic working medium in the organic working medium Rankine cycle assembly through the second heat exchanger 7 flows into the vortex tube 1, and is separated into two fluids through the vortex tube 1: high temperature carbon dioxide gas The gaseous carbon dioxide gas flows into the gaseous carbon dioxide storage tank 10 through the hot gas flow outlet 19 to prepare for the carbon dioxide energy release process; the low temperature carbon dioxide gas flows into the condenser 2 through the cold gas flow outlet 18, and a part of it is injected into the condenser 2 by the ejector 16. The jet fluid inlet 20, the other part is cooled into a liquid state in the condenser 2 and then flows into the liquid carbon dioxide storage tank 3, and the carbon dioxide energy storage process is completed.

During the organic working medium Rankine cycle process, the first valve 101 is opened, the liquid carbon dioxide flows through the first pump 4 to cool the organic working medium in the first heat exchanger 5, and then the carbon dioxide absorbs heat and evaporates into a gaseous state, which is stored until In the gaseous carbon dioxide storage tank 10, the organic working medium cooled by the first heat exchanger 5 flows into the second heat exchanger 7 for heating through the second pump 6, and the heated organic working medium flows into the first turbine 8 for expansion. Do work, and drive the generator 9 to generate electricity to supply power for the user, and the organic working fluid Rankine cycle process is completed.

In the carbon dioxide energy release process, the high temperature carbon dioxide gas flowing out through the hot gas flow outlet 19 of the vortex tube 1 flows into the gaseous carbon dioxide storage tank 10 together with the carbon dioxide gas obtained by heat exchange in the organic working medium Rankine cycle process. The second valve 102 is opened, the carbon dioxide gas flows into the compressor 11 for compression, and the compressed high-pressure carbon dioxide gas flows into the surge tank 12 for storage. After the carbon dioxide gas in the surge tank 12 is sufficient and the pressure is stable, the second control valve 102 is closed, and the third control valve 103 is opened, and the carbon dioxide gas flows into the third heat exchanger 14 through the regenerator 13 to receive domestic waste heat and produce waste heat. The heat from heat sources such as solar collectors and solar collectors becomes high temperature and high pressure carbon dioxide gas and flows into the second turbine 15 . At the same time, part of the carbon dioxide gas is extracted from the suction port of the second turbine 15 and flows into the working fluid inlet 21 to drive the ejector 16, thereby ejecting the uncondensed carbon dioxide gas in the condenser 2, and then the carbon dioxide gas passing through the ejector outlet 22 enters the return The heat exchanger 13 is mixed with the lower temperature carbon dioxide gas to become the higher temperature carbon dioxide gas, thereby increasing the temperature of the carbon dioxide gas before entering the third heat exchanger 14, reducing the heat source heat required by the third heat exchanger 14 and The cooling capacity required by the condenser 2; the remaining high temperature and high pressure carbon dioxide gas continues to do work in the second turbine 15, and the work done by the expansion of the organic working fluid in the first turbine 8 and the carbon dioxide gas in the second turbine 15 is part of It is used to drive the compressor 11, and the other part is used to drive the generator 9 to generate electricity. At this time, the temperature and pressure of the spent gas after the second turbine 15 has done work is still relatively high, and it is introduced into the second heat exchanger 7 as a heat source to supply heat for the organic working medium in the organic working medium Rankine cycle. The low-temperature carbon dioxide gas after passing through the second heat exchanger 7 flows into the vortex tube 1, and the carbon dioxide energy release process is completed.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be noted that, for those skilled in the art, modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. The protection scope of the patent of the present invention shall be subject to the appended claims.

Claims (10)

1. a liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube, characterized in that, comprising a vortex tube, a condenser, a liquid carbon dioxide storage tank, the first heat exchanger, the second heat exchanger, the first turbine , gaseous carbon dioxide storage tank, compressor, surge tank, regenerator, third heat exchanger, second turbine and ejector; The inlet of the condenser is communicated with the outlet of the cold air flow of the vortex tube, the first outlet of the condenser is communicated with the inlet of the liquid carbon dioxide storage tank, and the outlet of the hot air of the vortex tube is communicated with the first inlet of the gaseous carbon dioxide storage tank; The first inlet of the first heat exchanger is communicated with the outlet of the liquid carbon dioxide storage tank, the second outlet of the first heat exchanger is communicated with the second inlet of the second heat exchanger, and the second outlet of the second heat exchanger is communicated with the first turbine The inlet is communicated, and the outlet of the first turbine is communicated with the second inlet of the first heat exchanger; The second inlet of the gaseous carbon dioxide storage tank is communicated with the first outlet of the first heat exchanger, the outlet of the gaseous carbon dioxide storage tank is communicated with the inlet of the compressor, the outlet of the compressor is communicated with the inlet of the surge tank, and the outlet of the surge tank is communicated with the regenerator The first inlet is communicated with, the regenerator outlet is communicated with the first inlet of the third heat exchanger, the first outlet of the third heat exchanger is communicated with the second turbine inlet, and the second turbine suction port is communicated with the working fluid of the ejector The inlet communicates with the inlet, the ejection fluid inlet communicates with the second outlet of the condenser, and the ejector outlet communicates with the second inlet of the regenerator. 2 . The liquid carbon dioxide energy storage system based on the combination of ejector and vortex tube according to claim 1 , wherein a first valve is provided between the outlet of the liquid carbon dioxide storage tank and the first inlet of the first heat exchanger. 3 . . 3 . The liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to claim 1 , wherein a second valve is provided between the outlet of the gaseous carbon dioxide storage tank and the inlet of the compressor. 4 . 4 . The liquid carbon dioxide energy storage system based on the combination of ejector and vortex tube according to claim 1 , wherein a third valve is provided between the outlet of the surge tank and the first inlet of the regenerator. 5 . 5 . The liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to claim 1 , wherein a first pump is arranged between the first valve and the first inlet of the first heat exchanger. 6 . 6 . The liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to claim 1 , wherein a second outlet of the first heat exchanger and the second inlet of the second heat exchanger are arranged between the second outlet of the first heat exchanger and the second inlet of the second heat exchanger. second pump. 7 . The liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to claim 1 , wherein the organic working medium Rankine cycle working medium is R245fa, R11 or R12 working medium. 8 . 8 . The liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to claim 1 , wherein the compressor is coaxially arranged with the first turbine and the second turbine. 9 . 9 . The liquid carbon dioxide energy storage system based on the combination of ejector and vortex tube according to claim 1 , wherein the hot end of the third heat exchanger adopts domestic waste heat, production waste heat or solar heat collection heat source. 10 . 10. A liquid carbon dioxide energy storage system based on the combination of an ejector and a vortex tube according to claim 1, wherein the first turbine is externally connected with a generator, and the gaseous carbon dioxide working medium and the gaseous organic working medium can be respectively The first turbine and the second turbine do work, one part is used to drive the compressor, and the other part is used to drive the generator to generate electricity.

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