阅读说明：本技术 联合循环储能发电系统 (Combined cycle energy storage power generation system ) 是由 张谨奕 王含 白宁 李京浩 张玮 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种联合循环储能发电系统,联合循环储能发电系统包括斜温层储能发电系统和背压式发电系统,斜温层发电系统包括压缩机、透平、第一发电机、第一换向阀、熔盐罐、防冻液罐、熔盐换热器、中间换热器、第二换向阀和防冻液换热器,第一换向阀连接压缩机和透平,熔盐换热器连接熔盐罐和第一换向阀,中间换热器连接第一换向阀和熔盐换热器,中间换热器还与背压式发电系统相连,第二换向阀连接透平、中间换热器和压缩机,防冻液换热器与背压式发电系统相连,防冻液换热器还与第二换向阀相连。本发明实施例的联合循环储能发电系统提高了系统循环效率、储能密度、经济性,实现清洁低碳的闭式联合循环储能发电。(The invention discloses a combined cycle energy storage power generation system which comprises an inclined temperature layer energy storage power generation system and a back pressure type power generation system, wherein the inclined temperature layer power generation system comprises a compressor, a turbine, a first power generator, a first reversing valve, a molten salt tank, an anti-freezing liquid tank, a molten salt heat exchanger, an intermediate heat exchanger, a second reversing valve and an anti-freezing liquid heat exchanger, the first reversing valve is connected with the compressor and the turbine, the molten salt heat exchanger is connected with the molten salt tank and the first reversing valve, the intermediate heat exchanger is connected with the first reversing valve and the molten salt heat exchanger, the intermediate heat exchanger is also connected with the back pressure type power generation system, the second reversing valve is connected with the turbine, the intermediate heat exchanger and the compressor, the anti-freezing liquid heat exchanger is connected with the back pressure type power generation system, and the anti-freezing liquid heat exchanger is also connected with the second reversing valve. The combined cycle energy storage power generation system of the embodiment of the invention improves the cycle efficiency, the energy storage density and the economy of the system and realizes clean low-carbon closed combined cycle energy storage power generation.)

1. The utility model provides a combined cycle energy storage power generation system which characterized in that, includes thermocline energy storage power generation system and back pressure type power generation system, thermocline power generation system includes:

a compressor;

a turbine and a first generator coupled to the turbine;

the first reversing valve is provided with a first port, a second port, a third port and a fourth port, the first port of the first reversing valve is connected with the outlet of the compressor, and the third port of the first reversing valve is connected with the inlet of the turbine;

a molten salt tank having a first molten salt port and a second molten salt port;

the anti-freezing liquid tank is provided with a first anti-freezing liquid port and a second anti-freezing liquid port;

the molten salt heat exchanger is provided with a first molten salt heat exchanger port, a second molten salt heat exchanger port, a third molten salt heat exchanger port and a fourth molten salt heat exchanger port, the first molten salt heat exchanger port is connected with the first molten salt port, the second molten salt heat exchanger port is connected with the second molten salt port, and the third molten salt heat exchanger port is connected with the second valve port of the first reversing valve;

the intermediate heat exchanger is provided with first to fourth intermediate heat exchanger ports, the first intermediate heat exchanger port is connected with the fourth valve port of the first reversing valve, the second intermediate heat exchanger port is connected with the fourth molten salt heat exchanger port of the molten salt heat exchanger, and the third intermediate heat exchanger port is connected with the back-pressure power generation system through a first valve;

the second reversing valve is provided with a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port of the second reversing valve is connected with the outlet of the turbine, the second valve port of the second reversing valve is connected with the fourth intermediate heat exchanger port, and the third valve port of the second reversing valve is connected with the inlet of the compressor;

the anti-freezing solution heat exchanger is provided with first to fourth anti-freezing solution heat exchanger ports, the first anti-freezing solution heat exchanger port is connected with the back pressure type power generation system through a second valve, the second anti-freezing solution heat exchanger port is connected with a fourth valve port of the second reversing valve, the third anti-freezing solution heat exchanger port is connected with the first anti-freezing solution port, the fourth anti-freezing solution heat exchanger port is connected with the second anti-freezing solution port, and the third intermediate heat exchanger port is connected with the first anti-freezing solution heat exchanger port through a third valve.

2. The combined cycle energy storing and generating system of claim 1, wherein the back pressure power generating system comprises an expander, a second generator coupled to the expander, an evaporator having first through fourth evaporator ports, and a condenser comprising first through fourth condenser ports,

the first evaporator port is connected with the third intermediate heat exchanger port through the first valve, the second evaporator port is connected with the first antifreeze solution heat exchanger port through the second valve, the third evaporator port is connected with an inlet of the expansion machine, and the fourth evaporator port is connected with the second condenser port.

3. The combined cycle energy storing and generating system of claim 2, further comprising a heat consuming device, wherein the third condenser port is connected to an inlet of the heat consuming device and the fourth condenser port is connected to an outlet of the heat consuming device.

4. The combined cycle energy storing and generating system of claim 2, wherein a working medium pump is disposed between the fourth evaporator port and the second condenser port.

5. The combined cycle energy storing and generating system of claim 1, wherein an upper molten salt distributor adjacent the first molten salt port and a lower molten salt distributor adjacent the second molten salt port are disposed within the molten salt tank, and an upper antifreeze distributor adjacent the first antifreeze port and a lower antifreeze distributor adjacent the second antifreeze port are disposed within the antifreeze tank.

6. The combined cycle energy-storing and power-generating system of claim 1, wherein the first molten salt port is connected to the first molten salt heat exchanger port by a high temperature molten salt pump, and the second molten salt port is connected to the second molten salt heat exchanger port by a low temperature molten salt pump,

the first antifreezing fluid port is connected with the third antifreezing fluid heat exchanger port through a first antifreezing fluid pump, and the second antifreezing fluid port is connected with the fourth antifreezing fluid heat exchanger port through a second antifreezing fluid pump.

7. The combined cycle stored energy power generation system according to any one of claims 1 to 6, wherein the first and second valves are closed during a storage phase and the third valve is open, the first and second valves are open during a power generation phase and the third valve is closed.

Technical Field

The invention belongs to the technical field of energy storage, and particularly relates to a combined cycle energy storage power generation system.

Background

In the related technology, the circulation mode of the combined cycle energy storage power generation system during energy storage through a normal temperature working medium is as follows: compression-heat release through the second heat storage body-expansion work-heating-heat absorption through the first heat storage body, and the cycle mode when power is supplied is compression-heat absorption through the second heat storage body-expansion work-heat release through the first heat storage body-heating. However, in the related art, in the energy storage circulation mode, a single tank cannot be used for storing energy, otherwise, full heat and cold cannot be completely stored, and a double-tank energy storage must be used, which leads to a complex system and high cost.

Disclosure of Invention

The present invention is based on the discovery and recognition by the inventors of the following facts and problems:

the inventor of the present invention found and recognized through research that in the related art, a single tank cannot be used for energy storage in an energy storage cycle mode, otherwise, full heat and cold cannot be stored completely, and a double tank must be used for energy storage, but the system is complex and high in cost.

The document application number-CN 201810180017.8 discloses a heat pump type alternative energy storage and power supply method and device, which includes an energy storage and heat supply mode and a power supply and heat supply mode. The energy storage and power supply system is characterized in that the energy storage and power supply functions are achieved by alternately storing and releasing energy through two sets of heat storage systems in an energy storage heat supply mode and a power supply heat supply mode. When an energy storage heat supply mode is adopted, a normal-temperature working medium absorbs heat through a first heat storage system in an isobaric manner, is subjected to adiabatic compression through a compressor, releases heat through a second heat storage system in an isobaric manner, then enters a turbine for adiabatic expansion to apply work to the outside, and finally is released to the outside as a heating source; the device is sequentially connected with an air inlet device, a first heat exchanger, a first heat storage system, a compressor, a second heat exchanger, a second heat storage system, a turbine and an air outlet device in series along the direction of working gas. The other mode is a heating and power supply mode. The normal-temperature working medium is subjected to adiabatic compression by the compressor, isobaric heat absorption is carried out through the second heat storage system, then the working medium enters the turbine for adiabatic expansion to apply work to the outside, isobaric heat release is carried out through the first heat storage system, and finally the working medium is released to the outside as a heating source; in this process the net output work is used to power. According to the technical scheme, the heat pump type alternative energy storage and power supply method and the heat pump type alternative energy storage and power supply device solve the problems of wind abandoning and light abandoning in photovoltaic power generation and wind power generation and the problem of peak clipping and valley filling of peak valley electricity, heat is supplied while energy storage and power supply are performed, waste heat of waste gas is recycled in another heat storage system, and heat-power conversion efficiency is improved.

However, in the document CN201810180017.8, the circulation mode during energy storage (power storage) by the normal temperature working medium is: compression-release of heat (via the second heat accumulator) -expansion work-heating-absorption of heat (via the first heat accumulator); the cycle mode when supplying power is: compression-absorption of heat (via the second heat accumulator) -expansion to do work-release of heat (via the first heat accumulator) -heating. In the energy storage circulation mode, if single-tank energy storage is adopted, full heat and cold cannot be completely stored; if double tanks are adopted for energy storage, the full heat and cold can be stored; in the power supply cycle mode, in order to maintain the temperature difference and the energy conversion efficiency between the second heat storage body as the high-temperature heat source and the first heat storage body as the low-temperature heat source, the temperature of the second heat storage body needs to be increased; the system is open cycle, and is not suitable for use when the cycle working medium is helium, argon and other gases.

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, an embodiment of the present invention provides a combined cycle energy storage power generation system, which includes an thermocline energy storage power generation system and a back pressure power generation system. The thermocline power generation system comprises: a compressor; a turbine and a first generator coupled to the turbine; the first reversing valve is provided with a first port, a second port, a third port and a fourth port, the first port of the first reversing valve is connected with the outlet of the compressor, and the third port of the first reversing valve is connected with the inlet of the turbine; a molten salt tank having a first molten salt port and a second molten salt port; the anti-freezing liquid tank is provided with a first anti-freezing liquid port and a second anti-freezing liquid port; the molten salt heat exchanger is provided with a first molten salt heat exchanger port, a second molten salt heat exchanger port, a third molten salt heat exchanger port and a fourth molten salt heat exchanger port, the first molten salt heat exchanger port is connected with the first molten salt port, the second molten salt heat exchanger port is connected with the second molten salt port, and the third molten salt heat exchanger port is connected with the second valve port of the first reversing valve; the intermediate heat exchanger is provided with first to fourth intermediate heat exchanger ports, the first intermediate heat exchanger port is connected with the fourth valve port of the first reversing valve, the second intermediate heat exchanger port is connected with the fourth molten salt heat exchanger port of the molten salt heat exchanger, and the third intermediate heat exchanger port is connected with the back-pressure power generation system through a first valve; the second reversing valve is provided with a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port of the second reversing valve is connected with the outlet of the turbine, the second valve port of the second reversing valve is connected with the fourth intermediate heat exchanger port, and the third valve port of the second reversing valve is connected with the inlet of the compressor; the anti-freezing solution heat exchanger is provided with first to fourth anti-freezing solution heat exchanger ports, the first anti-freezing solution heat exchanger port is connected with the back pressure type power generation system through a second valve, the second anti-freezing solution heat exchanger port is connected with a fourth valve port of the second reversing valve, the third anti-freezing solution heat exchanger port is connected with the first anti-freezing solution port, the fourth anti-freezing solution heat exchanger port is connected with the second anti-freezing solution port, and the third intermediate heat exchanger port is connected with the first anti-freezing solution heat exchanger port through a third valve.

According to the combined cycle energy storage power generation system disclosed by the embodiment of the invention, waste heat utilization is realized by adopting an inclined temperature layer energy storage power generation system and a combined back pressure type power generation system, and the efficiency of the combined cycle energy storage power generation system is improved. The invention aims at the characteristics of instability and intermittence of renewable energy sources, can stabilize the instability of power generation of the renewable energy sources such as wind power generation or photovoltaic power generation and the like, realizes the stable output of the power of the renewable energy sources, has the effect of balancing power supply and demand, can realize large-scale energy storage, exerts the advantages of energy storage and peak regulation, and responds to the energy storage requirement of the renewable energy sources.

In some embodiments, the back pressure power generation system includes an expander, a second generator coupled to the expander, an evaporator having first through fourth evaporator ports, and a condenser including first through fourth condenser ports, the first evaporator port coupled to the third intermediate heat exchanger port via the first valve, the second evaporator port coupled to the first antifreeze heat exchanger port via the second valve, the third evaporator port coupled to an inlet of the expander, and the fourth evaporator port coupled to the second condenser port.

In some embodiments, the combined cycle energy storage and power generation system further comprises a heat consuming device, the third condenser port is connected to an inlet of the heat consuming device, and the fourth condenser port is connected to an outlet of the heat consuming device.

In some embodiments, a working medium pump is arranged between the fourth evaporator port and the second condenser port.

In some embodiments, an upper molten salt distributor adjacent to the first molten salt port and a lower molten salt distributor adjacent to the second molten salt port are disposed in the molten salt tank, and an upper antifreeze distributor adjacent to the first antifreeze port and a lower antifreeze distributor adjacent to the second antifreeze port are disposed in the antifreeze tank.

In some embodiments, the first molten salt port is connected to the first molten salt heat exchanger port by a high temperature molten salt pump, the second molten salt port is connected to the second molten salt heat exchanger port by a low temperature molten salt pump, the first antifreeze port is connected to the third antifreeze heat exchanger port by a first antifreeze pump, and the second antifreeze port is connected to the fourth antifreeze heat exchanger port by a second antifreeze pump.

In some embodiments, the first and second valves are closed during the charging phase and the third valve is open, the first and second valves are open during the power generation phase and the third valve is closed.

According to the thermocline circulating energy storage power generation system and the combined back pressure type power generation system provided by the embodiment of the invention, a combined energy storage power generation circulating system is formed. According to the invention, the single-tank molten salt heat storage and the single-tank antifreeze liquid cold storage are adopted to improve the energy storage density, the intermediate heat exchanger is used to reduce the circulating pressure ratio and stabilize the temperature of the high-temperature end and the low-temperature end of the system, and the combined back pressure type ORC power generation system realizes the waste heat utilization and stable working condition point of the whole system, so that the system circulation efficiency, the energy storage density and the economy are improved, the safe and stable operation of the system is ensured, and the clean and low-carbon closed combined circulating energy storage power generation is realized.

Drawings

FIG. 1 is a schematic diagram of the charging phase of a combined cycle energy storage and power generation system according to an embodiment of the invention.

FIG. 2 is a schematic diagram of the power generation phases of a combined cycle energy storage power generation system according to an embodiment of the invention.

Reference numerals:

the system comprises an inclined temperature layer energy storage power generation system 100, a back pressure type power generation system 200, a compressor 2, a turbine 6, a first power generator 7, a molten salt inclined temperature layer 11, a molten salt lower distributor 12, a low-temperature molten salt pump 13, a molten salt upper distributor 14, a high-temperature molten salt pump 15, an antifreeze inclined temperature layer 17, an antifreeze upper distributor 18, a first antifreeze pump 19 and an antifreeze lower distributor 20. A second antifreeze liquid pump 21, a third valve 22, a working medium pump 26, a heat utilization device 27, a water pump 28, a first valve 29, a second valve 30, a second generator 31,

a first direction valve 3, a first valve port 31 of the first direction valve, a second valve port 32 of the first direction valve, a third valve port 33 of the first direction valve, a fourth valve port 34 of the first direction valve,

a molten salt tank 10, a first molten salt port 101, a second molten salt port 102, an antifreeze tank 16, a first antifreeze port 161, a second antifreeze port 162,

a molten salt heat exchanger 4, a first molten salt heat exchanger port 41, a second molten salt heat exchanger port 42, a third molten salt heat exchanger port 43, a fourth molten salt heat exchanger port 44,

an intermediate heat exchanger 5, a first intermediate heat exchanger port 51, a second intermediate heat exchanger port 52, a third intermediate heat exchanger port 53, a fourth intermediate heat exchanger port 54,

a second direction valve 8, a first port 81 of the second direction valve, a second port 82 of the second direction valve, a third port 83 of the second direction valve, a fourth port 84 of the second direction valve,

an antifreeze heat exchanger 9, a first antifreeze heat exchanger port 91, a second antifreeze heat exchanger port 92, a third antifreeze heat exchanger port 93, a fourth antifreeze heat exchanger port 94,

the expander 24, the expander inlet 241, the expander inlet 242,

evaporator 23, first evaporator port 231, second evaporator port 232, third evaporator port 233, fourth evaporator port 234,

condenser 25, first condenser port 251, second condenser port 252, third condenser port 253, fourth condenser port 254.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1 and 2, the combined cycle energy storage and power generation system according to the embodiment of the invention includes a thermocline energy storage and power generation system 100 and a back pressure power generation system 200, and the thermocline power generation system 100 includes a compressor 2, a turbine 6, a first generator 7, a first reversing valve 3, a molten salt tank 10, an antifreeze tank 16, a molten salt heat exchanger 4, an intermediate heat exchanger 5, a second reversing valve 8 and an antifreeze heat exchanger 9.

The inlet of the compressor 2 is connected to the motor 1. The inlet 62 of the turbine 6 is connected to a first generator.

The first reversing valve 3 is provided with a first port, a second port, a third port and a fourth port, wherein the first port 31 of the first reversing valve is connected with the outlet of the compressor 2, and the third port 33 of the first reversing valve is connected with the inlet of the turbine 6;

the molten salt tank 10 has a first molten salt port 101 and a second molten salt port 102. The antifreeze tank 16 has a first antifreeze port 161 and a second antifreeze port 162.

The molten salt heat exchanger 4 is provided with a first molten salt heat exchanger port, a second molten salt heat exchanger port and a third molten salt heat exchanger port, wherein the first molten salt heat exchanger port 41 is connected with the first molten salt port 101, the second molten salt heat exchanger port 42 is connected with the second molten salt port 102, and the third molten salt heat exchanger port 43 is connected with the second valve port 32 of the first reversing valve.

The intermediate heat exchanger 5 is provided with first to fourth intermediate heat exchanger ports, the first intermediate heat exchanger port 51 is connected with the fourth valve port 34 of the first reversing valve, the second intermediate heat exchanger port 52 is connected with the fourth molten salt heat exchanger port 44 of the molten salt heat exchanger 4, and the third intermediate heat exchanger port 53 is connected with the back-pressure power generation system 200 through the first valve 29.

The second reversing valve 8 is provided with a first port 81, a second port 82 and a third port 83, wherein the first port 81 is connected with the outlet of the turbine 6, the second port 82 is connected with the fourth intermediate heat exchanger port 54, and the third port 83 is connected with the inlet of the compressor 2;

the antifreeze heat exchanger 9 has first to fourth antifreeze heat exchanger ports, the first antifreeze heat exchanger port 91 is connected to the back-pressure power generation system 200 through the second valve 30, the second antifreeze heat exchanger port 92 is connected to the fourth valve port 84 of the second reversing valve, the third antifreeze heat exchanger port 93 is connected to the first antifreeze port 161, the fourth antifreeze heat exchanger port 94 is connected to the second antifreeze port 162, and the third intermediate heat exchanger port 53 is connected to the first antifreeze heat exchanger port 91 through the third valve 22.

The back pressure power generation system 200 includes an expander 24, a second generator 31, an evaporator 23, and a condenser 25.

The evaporator 23 has first to fourth evaporator ports, and the condenser 25 includes first to fourth condenser ports. The first evaporator port 231 is connected to the third intermediate heat exchanger port 53 via the first valve 29, the second evaporator port 232 is connected to the first antifreeze heat exchanger port 91 via the second valve 30, the third evaporator port 233 is connected to the inlet of the expander 24, and the fourth evaporator port 234 is connected to the second condenser port 252.

The combined cycle energy storage and power generation system further comprises a heat consuming device 27, wherein the third condenser port 253 is connected with an inlet of the heat consuming device 27, and the fourth condenser port 254 is connected with an outlet of the heat consuming device 27.

A working medium pump 26 is arranged between the fourth evaporator port 234 and the second condenser port 252.

The molten salt tank 10 is provided with a molten salt upper distributor 14 adjacent to the first molten salt port 101 and a molten salt lower distributor 12 adjacent to the second molten salt port 102, and the antifreeze tank 16 is provided with an antifreeze upper distributor 18 adjacent to the first antifreeze port 161 and an antifreeze lower distributor 20 adjacent to the second antifreeze port 162.

The first molten salt port 101 is connected with the first molten salt heat exchanger port 41 through a high-temperature molten salt pump 15, the second molten salt port 102 is connected with the second molten salt heat exchanger port 42 through a low-temperature molten salt pump 13, the first antifreeze liquid port 161 is connected with the third antifreeze liquid heat exchanger port 93 through a first antifreeze liquid pump 19, and the second antifreeze liquid port 162 is connected with the fourth antifreeze liquid heat exchanger port 94 through a second antifreeze liquid pump 21.

The first and second valves 29, 30 are closed during the charging phase and the third valve 22 is open, the first and second valves 29, 30 are open during the generating phase and the third valve 22 is closed.

Some specific exemplary combined cycle energy storage and generation systems according to the invention are described below with reference to FIGS. 1-2. As shown in fig. 1-2, a combined cycle energy storage and power generation system according to an embodiment of the invention includes the following four devices.

1. Electric-to-heat/cold conversion (device), i.e. energy storage cycle phase.

In the energy storage stage of the thermocline energy storage power generation system 100, the gaseous working medium is subjected to Brayton reverse circulation, and electric energy is utilized to drive the gaseous working medium to complete circulation, so that the electric energy is converted into heat energy and cold energy to be stored. The compressor 2, the first reversing valve 3, the molten salt heat exchanger 4, the intermediate heat exchanger 5, the turbine 6, the second reversing valve 8, the antifreeze heat exchanger 9, the third valve 22 (fully open), the intermediate heat exchanger 5 and the second reversing valve 8 are started to a loop of the compressor 2, the compressor 2 is driven by the electric drive motor 1, and the compressor 2 applies work to convert electric energy into energy of high-temperature gaseous working media. The high-temperature gaseous working medium heats the low-temperature fused salt when flowing into the fused salt heat exchanger 4 through the first reversing valve 3 to become the medium-temperature gaseous working medium, and then the medium-temperature gaseous working medium passes through the intermediate heat exchanger 5 to heat the low-temperature gaseous working medium at the inlet of the compressor 2, thereby effectively reducing the compression ratio of the compressor 2 and the expansion ratio of the turbine 6, ensuring the efficiency of the thermal power plant and reducing the design and manufacture difficulty of the thermal power plant, simultaneously reducing the outlet temperature deviation caused by the reduction of the heat exchange efficiency of the heat storage device (fused salt tank) and the cold storage device (anti-freezing liquid tank), and maintaining the operation stability of the inclined temperature layer energy storage power generation system 100 in the energy storage stage.

The medium-temperature gaseous working medium flows out after passing through the intermediate heat exchanger 5, flows to the turbine 6 after passing through the first reversing valve 3, is expanded by the turbine 6 and then is cooled to become a low-temperature gaseous working medium, the low-temperature gaseous working medium passes through the second reversing valve 8, firstly flows into the antifreeze heat exchanger 9 for cooling the antifreeze, then flows into the intermediate heat exchanger 5 for heating, and flows to the compressor 2 after passing through the second reversing valve 8, so that an energy storage cycle is completed.

The gaseous working medium has the characteristics of low viscosity, high heat conductivity and specific heat capacity. Including but not limited to air, nitrogen, argon, other inert gases, carbon dioxide, hydrogen, oxygen, or combinations thereof.

During the energy storage cycle, the back-pressure power generation system 200 is off. The first valve 29 is closed, the second valve 30 is closed, and the third valve 22 is opened.

2. Heat/cold-electricity conversion (device) (same set of devices as electricity-heat/cold conversion, which is a power generation cycle).

The thermocline energy storage power generation system 100 starts power cycle of heat/cold-electricity conversion in a power generation stage, the process is the reverse process of electricity-heat/cold conversion, a gaseous working medium performs Brayton cycle, at the moment, the work of the turbine 6 is greater than that of the compressor 2, the first generator 7 is driven to generate power, and the system outputs power to the outside for supplying power. The method comprises the steps that a compressor 2, a first reversing valve 3, an intermediate heat exchanger 5, a molten salt heat exchanger 4, a first reversing valve 3, a turbine 6, a second reversing valve 8, the intermediate heat exchanger 5, a first valve 29 (full open), an evaporator 23, a second valve 30 (full open), an anti-freezing solution heat exchanger 9, a second reversing valve 8 and a compressor 2 are started, low-temperature gaseous working media are compressed by the compressor 2 and enter the first reversing valve 3, first flow through the intermediate heat exchanger 5 to become medium-temperature gaseous working media, then flow through the molten salt heat exchanger 4 to be heated, and flow into the turbine 6 to do work through expansion. The medium-temperature gaseous working medium which does work by the turbine 6 enters the second reversing valve 8, firstly flows through the intermediate heat exchanger 5, heats the low-temperature gaseous working medium at the outlet of the compressor 2 to become medium-low temperature gaseous working medium, then flows through the evaporator 23 to release heat, then flows through the antifreeze heat exchanger 9 to be cooled, and the cooled low-temperature gaseous working medium flows through the second reversing valve 8 and then enters the inlet of the compressor 2 to complete one round of power generation circulation. In the power generation stage, the intermediate-temperature gaseous working medium after expansion work is heated by the intermediate heat exchanger 5 to heat the low-temperature gaseous working medium at the outlet of the compressor, so that the compression ratio of the compressor and the expansion ratio of the turbine are effectively reduced, the efficiency and the reliability of the thermal power equipment are ensured, and the inlet temperature stability of the heat storage and cold storage device is ensured; by arranging the evaporator 23, the waste heat of the medium-low temperature gaseous working medium is recovered, the circulation efficiency of the whole system is improved, and the operation stability of the system in the power generation stage is maintained.

3. Energy storage device

The energy storage device is 2 heat-insulating tanks with high heat preservation performance, and comprises a molten salt tank 10, an antifreeze tank 16, an upper distributor, a lower distributor and a pump which are attached to the antifreeze tank. The heat energy is stored in the molten salt tank 10 in the form of high-temperature molten salt heat energy, and is stored in the antifreeze liquid tank 16 in the form of low-temperature antifreeze liquid heat energy. At the moment of finishing energy storage, the molten salt tank 10 is full of high-temperature molten salt from top to bottom, and the low-temperature molten salt at the bottom is completely emptied; the antifreeze liquid tank 16 is filled with the low-temperature antifreeze liquid from bottom to top, and the high-temperature antifreeze liquid at the upper part is completely emptied.

Adopting an antifreeze with the freezing point lower than 0 ℃ as a low-temperature end cold storage medium, wherein the working temperature range of the antifreeze can be-100-10 ℃, and the antifreeze can be, but is not limited to, methanol aqueous solution, ethanol aqueous solution, glycol aqueous solution, glycerol aqueous solution and saline aqueous solution (calcium chloride, magnesium chloride, sodium nitrate and sodium nitrite); low-melting-point salts (nitrate and chloride) are used as a high-temperature-end heat storage medium, so that the risk of molten salt solidification and the requirement of a system on molten salt solidification prevention are reduced; the working temperature of the anti-freezing solution is reasonably designed, the temperature of the high-temperature end of the system is reduced while the energy conversion efficiency of the system is ensured, and the requirement of the system on expensive high-temperature-resistant equipment/materials is reduced.

In the energy storage cycle stage, the operation mode of the energy storage device is as follows:

the low temperature molten salt pump 13 drives the low temperature fused salt and flows out through distributor 12 under the fused salt from the bottom of fused salt jar 10, and molten salt heat exchanger 4 flows through, and the low temperature fused salt is heated and becomes high temperature fused salt, and the high temperature fused salt passes through distributor 14 on the fused salt, flows into the upper portion space of fused salt jar 10, through distributor 14 and lower distributor 12 on the fused salt, ensures that fused salt inclined temperature layer 11 effectively keeps apart upper portion high temperature fused salt and lower part low temperature fused salt, and the heat-retaining of the high temperature end of system is accomplished promptly after fused salt jar 10 stores up full high temperature fused salt.

The antifreeze liquid pump 19 drives the antifreeze liquid to flow out from the upper space of the antifreeze liquid tank 16 and the antifreeze liquid upper distributor 18, the antifreeze liquid flows through the antifreeze liquid heat exchanger 9, the high-temperature antifreeze liquid is cooled to become the low-temperature antifreeze liquid, and the antifreeze liquid flows to the lower space of the antifreeze liquid tank 16 through the antifreeze liquid lower distributor 20, the antifreeze liquid inclined temperature layer 17 is ensured to effectively isolate the upper high-temperature antifreeze liquid from the lower low-temperature antifreeze liquid through the design of the antifreeze liquid upper distributor 18 and the antifreeze liquid lower distributor 20, and the cold storage of the low-temperature end of the system is completed after the antifreeze liquid tank 16 is fully filled with the low-temperature antifreeze liquid.

In the power generation cycle stage, the operation mode of the energy storage device is as follows:

the high-temperature molten salt pump 15 drives high-temperature molten salt to flow out from the upper portion of the molten salt tank 10 through the molten salt upper distributor 14 and flow through the molten salt heat exchanger 4, the high-temperature molten salt is heated to form low-temperature molten salt through a gaseous working medium, the low-temperature molten salt flows into the lower space of the molten salt tank 10 through the molten salt upper distributors 14 and 12, the molten salt inclined temperature layer 11 is guaranteed to effectively isolate the upper high-temperature molten salt and the lower low-temperature molten salt through the lower distributor, and the system power generation process is completed after the molten salt tank 10 is fully stored with the low-temperature molten salt.

The antifreeze liquid pump 21 drives the antifreeze liquid to flow out from the antifreeze liquid lower distributor 20 in the lower space of the antifreeze liquid tank 16, the antifreeze liquid flows through the antifreeze liquid heat exchanger 9, the low-temperature antifreeze liquid cools the gaseous working medium, the gaseous working medium flows to the upper space of the antifreeze liquid tank 16 after passing through the antifreeze liquid upper distributor 18, the antifreeze liquid upper distributor 18 and the antifreeze liquid lower distributor 20 are designed to ensure that the antifreeze liquid inclined temperature layer 17 effectively isolates the upper high-temperature antifreeze liquid and the lower low-temperature antifreeze liquid, and the system power generation process is completed after the antifreeze liquid tank 16 is filled with the high-temperature antifreeze liquid.

At the time of completing system discharge, the molten salt tank 10 is full of low-temperature molten salt from bottom to top, and the upper high-temperature molten salt is completely emptied; the antifreeze liquid tank 16 is filled with high-temperature antifreeze liquid from top to bottom, and the low-temperature antifreeze liquid at the lower part is completely emptied. And starting the next energy storage and power generation cycle.

4. Back pressure type power generation system

During the power generation phase, the back pressure power generation system is opened, valves 29 and 30 are opened, and valve 22 is closed. The system performs power generation circulation and heat supply at the same time, the waste heat of the thermocline energy storage and power generation system 100 is used as an evaporator heat source, the expander 24 applies work to drive the second generator 31 to generate power, and the system supplies power to the outside; while the condenser 25 in the system releases heat for supplying heat to the user device 27.

In the back-pressure power generation system loop evaporator 23-expander 24-condenser 25-working medium pump 26-evaporator 23, working medium performs ORC power circulation, working medium steam at the outlet of the evaporator 23 enters the expander 24, enthalpy drop is converted into mechanical energy of the expander 24, and the mechanical energy drives the second generator 31 to generate power. The working medium steam at the outlet of the expander 24 enters the condenser 25, is condensed to release heat to form liquid, the liquid working medium passes through the working medium pump 26, is pressurized and then enters the evaporator again, and enters the expander 31 to do work after being gasified, so that a round of power generation cycle is completed. In the back pressure power generation system, the condenser 25 releases heat to heat circulating water, and the circulating water supplies heat to user devices 27 such as a factory building and a control room.

Wherein the working fluids include, but are not limited to, mixed working fluids of R12, R123, R125, R134a, R152a, R600a, R600, R290, and any combination thereof.

In the energy storage stage, the back pressure type power generation system is closed. Valves 29 and 30 are closed and valve 22 is opened.

The combined cycle energy storage power generation system comprises a Brayton cycle-based thermocline energy storage power generation system and an ORC cycle-based back pressure power generation system. The thermocline energy storage and power generation system adopts single-tank molten salt as a high-temperature-end heat storage medium, adopts single-tank antifreeze as a low-temperature-end cold storage medium, and adopts a gaseous working medium as a working medium for energy storage and power generation circulation. The back pressure type power generation system utilizes the waste heat of the thermocline energy storage power generation system to drive ORC power circulation to generate power and supply heat.

In the energy storage stage, the thermocline energy storage power generation system performs energy storage circulation, the gaseous working medium performs a cycle process of compression, heat release, expansion work application and heat absorption, the compressor works more than the turbine, and the electric energy is input into the system from the outside and then is stored in the form of heat energy and cold energy. The gaseous working medium absorbs heat from the antifreeze and releases heat to the molten salt. The compressed high-temperature gaseous working medium is heated by a heat exchanger to form low-temperature molten salt and medium-temperature gaseous working medium; the medium-temperature gaseous working medium passes through the intermediate heat recovery device to heat the low-temperature gaseous working medium at the inlet of the compressor, so that the compression ratio and the turbine expansion ratio of the compressor are effectively reduced, the efficiency of the thermal power equipment is ensured, and the design and manufacturing difficulty of the thermal power equipment is reduced; the temperature deviation of the outlet caused by the reduction of the heat exchange efficiency of the heat storage and cold storage device is reduced, and the operation stability of the system in the energy storage stage is maintained. The medium-temperature gaseous working medium is cooled into a low-temperature gaseous working medium after being expanded by the turbine, the low-temperature gaseous working medium flows into the intermediate heat recovery device after being cooled by the antifreeze liquid through the heat exchanger, and flows into the compressor after being heated to complete an energy storage cycle. In the energy storage stage, the back pressure type power generation system is closed.

The operation mode of the energy storage device is that at the high-temperature end of the system, low-temperature molten salt flows out from the lower space of the molten salt tank and becomes high-temperature molten salt after heat exchange of the heat exchanger, and the high-temperature molten salt flows into the upper space of the molten salt tank from the upper distributor of the molten salt tank and is stored. At the low temperature end of the system, high-temperature antifreeze flows out from the upper space of the antifreeze tank and becomes low-temperature antifreeze after heat exchange by the heat exchanger, and the low-temperature antifreeze flows into the lower space of the antifreeze tank from the lower distributor of the antifreeze tank and is stored. The design of the upper distributor and the lower distributor in the same storage tank realizes the effective isolation of high-temperature molten salt and low-temperature molten salt, high-temperature antifreeze solution and low-temperature antifreeze solution through the inclined temperature layer, after the energy storage is completed, the molten salt tank is filled with the high-temperature molten salt, the antifreeze solution tank is filled with the low-temperature antifreeze solution, the heat of the high-temperature end of the circulating electricity storage system is stored in the molten salt tank, and the heat of the low-temperature end of the circulating electricity storage system is stored in the antifreeze solution tank, so that the temperature difference between the high-temperature end and the low-temperature end of the system is efficiently maintained.

In the power generation stage, the thermocline energy storage power generation system performs power generation circulation, the gaseous working medium performs a cycle process of compression, heat absorption, expansion work and heat release, the gaseous working medium absorbs heat from the high-temperature molten salt and releases heat to the antifreeze, at the moment, the work of the turbine is greater than that of the compressor to drive the generator to generate power, and the system outputs the power to the outside in a net mode to supply power. The low-temperature gaseous working medium is compressed by the compressor and then enters the reversing valve, flows through the intermediate heat recovery device to become a medium-temperature gaseous working medium, flows through the fused salt heat exchanger to be heated, becomes a high-temperature gaseous working medium, and then flows into the turbine to expand and do work. The medium-temperature gaseous working medium which is acted by the turbine enters the reversing valve, firstly flows through the intermediate heat recovery device, heats the low-temperature gaseous working medium at the outlet of the compressor, becomes the medium-temperature and low-temperature gaseous working medium, then flows through the antifreeze heat exchanger to be cooled, and completes a power generation cycle. In the power generation stage, the intermediate-temperature gaseous working medium after expansion work is heated by the intermediate heat recovery device to heat the low-temperature gaseous working medium at the outlet of the compressor, so that the compression ratio of the compressor and the expansion ratio of a turbine are effectively reduced, and the efficiency and the reliability of the thermal power equipment are ensured; meanwhile, the inlet temperature of the heat storage and cold storage device is ensured to be stable, and the operation stability of the system in the power generation stage is maintained.

In the power generation stage, the back pressure type power generation system is started to perform power generation circulation, waste heat of the inclined temperature layer energy storage power generation system is used as a heat source of the evaporator, working medium steam at the outlet of the evaporator enters the expansion machine, enthalpy drop is converted into mechanical energy of the expansion machine, and the generator is driven to generate power. Working medium steam at the outlet of the expansion machine enters a condenser, is condensed to release heat to form liquid, liquid working medium is boosted by a working medium pump and then enters the evaporator again, and the liquid working medium is gasified and then enters the expansion machine to do work to complete one round of power generation circulation. In the back pressure type power generation system, the condenser releases heat to heat circulating water, and the circulating water supplies heat for hot users such as a factory building.

The operation mode of the energy storage device in the power generation stage is that high-temperature molten salt flows out from the upper space of the molten salt tank, exchanges heat through the heat exchanger and then flows back to the lower space of the molten salt tank; the low-temperature antifreeze liquid flows out from the lower space of the antifreeze liquid tank, and flows back to the upper space of the antifreeze liquid tank after heat exchange by the heat exchanger. And after the power generation is finished, the molten salt tank is filled with low-temperature molten salt, and the anti-freezing solution tank is filled with high-temperature anti-freezing solution. The design of the upper distributor and the lower distributor in the single tank realizes the effective isolation of high-temperature molten salt and low-temperature molten salt, and high-temperature and low-temperature antifreeze liquid through the inclined temperature layer, so that when the gaseous working medium performs the power generation cycle process, the temperature of the high-temperature end and the low-temperature end of the system is constant, and the energy conversion efficiency of the system is ensured.

The combined cycle energy storage power generation system according to the embodiment of the invention has the following beneficial technical effects.

1. In the energy storage stage, the gaseous working medium of the thermocline energy storage power generation system performs reverse Brayton cycle, and the working medium absorbs heat from the antifreeze and releases heat to the molten salt. By the design of the upper molten salt distributor 14 and the lower distributor 12, the inclined molten salt temperature layer 11 is ensured to effectively isolate the upper high-temperature molten salt and the lower low-temperature molten salt, and heat storage at the high-temperature end of the system is completed after the molten salt tank 10 is filled with the high-temperature molten salt; through the design of the upper antifreeze distributor 18 and the lower antifreeze distributor 20, the antifreeze inclined temperature layer 17 is ensured to effectively isolate the upper high-temperature antifreeze and the lower low-temperature antifreeze, and when the antifreeze tank 16 is filled with the low-temperature antifreeze, the cold storage at the low-temperature end of the system is completed. The design reduces the mixing of high/low temperature energy storage media and the thickening of the thermocline when the thermocline runs; the heat storage/cold storage is completed in the single tank, the energy storage density is improved, and the cost is reduced.

2. In the power generation stage, the gaseous working medium of the thermocline energy storage power generation system is subjected to Brayton cycle, and the working medium absorbs heat from the molten salt and releases heat to the antifreeze. The temperature of the high-temperature end of the system is kept constant by the design of the lower molten salt distributor 12 and the upper distributor 14; the temperature of the low temperature end is maintained constant by the design of the upper and lower distributors 18, 20 for the anti-icing liquid.

3. In the power generation stage, the back pressure type power generation system is combined to carry out ORC power circulation, the waste heat of the medium-low temperature gaseous working medium in the circulation process of the thermocline energy storage power generation system is recovered, the system is used for power generation and heat supply, the combined circulation efficiency is improved, the stability of the system working condition point is ensured, the safety and the stability of the system are enhanced, and the economy is improved.

4. The working medium is in closed circulation in the energy storage and power generation stages, no emission and pollution are caused, and clean, low-carbon, efficient and energy-saving energy storage and power generation are realized.

5. The thermocline energy storage power generation system adopts a main device consisting of a compressor, a heat exchanger, a reversing valve, a heat regenerator and a turbine, and realizes that the same device finishes reciprocal electricity-heat/cold conversion cycle and heat/cold-electricity conversion cycle by the design of a first reversing valve 3 and a second reversing valve 8, thereby simplifying the system structure.

6. Through the intermediate heat exchanger 5, in the energy storage stage, the intermediate-temperature gaseous working medium at the outlet of the heat storage system is used for heating the low-temperature gaseous working medium at the inlet of the compressor; in the power generation stage, the high-temperature gaseous working medium at the turbine outlet is used for heating the low-temperature gaseous working medium at the compressor outlet. The design reduces the compression ratio of the compressor and the expansion ratio of the turbine, ensures the efficiency of the thermal power equipment and reduces the design and manufacture difficulty of the thermal power equipment; the outlet temperature deviation caused by the reduction of the heat exchange efficiency of the heat storage and cold storage device is reduced in the energy storage stage; and the inlet temperature of the heat storage and cold storage device is ensured to be stable in the power generation stage, so that the operation stability of the system is maintained.

7. Molten salt is used as a heat storage medium, and an antifreeze is used as a cold storage medium. The design of low compression ratio ensures that the system can ensure the cycle efficiency without extreme high temperature and extreme low temperature; the temperature of the high-temperature end of the system is reduced, the requirement of the system on high-temperature resistant equipment/materials is reduced, and the system cost is reduced.

8. The energy storage power generation mode is universally applicable to thermal power peak regulation, stabilization of instability of power generation of renewable energy sources such as wind power or photovoltaic power generation and the like, peak shifting and valley filling, alleviation of the problems of wind abandoning and light abandoning and cogeneration.

An inclined temperature layer circulating energy storage power generation system is combined with a back pressure type power generation system to form an energy storage power generation circulating system. Single-tank molten salt heat storage and single-tank anti-freezing liquid cold storage are adopted, and the temperature difference between a high-temperature end and a low-temperature end of the circulation is effectively maintained by utilizing an inclined temperature layer technology, so that the energy storage density is improved; the same device is adopted, and energy storage and power generation are realized by the system; the reversing valve is used for changing the flow direction, and the intermediate heat recovery device (intermediate heat exchanger) is used for properly reducing the compression ratio and stabilizing the temperature of the high-temperature end and the low-temperature end. The combined back-pressure ORC power generation system realizes waste heat utilization and stable working point of the whole system, improves the system circulation efficiency, energy storage density and economy, ensures the safe and stable operation of the system, and realizes clean and low-carbon closed combined cycle energy storage power generation.

Through the forward-backward circulation of the same thermal power device, the single-tank heat/cold storage device and the heat exchange device, the system structure is simplified, the energy storage density is improved, the energy conversion efficiency is ensured, and the cost of the thermal power equipment and the cost of the energy storage device are reduced.

According to the combined cycle energy storage power generation system provided by the embodiment of the invention, the instability of power generation of renewable energy sources such as wind power generation or photovoltaic power generation and the like is stabilized, the stable power output of the renewable energy sources is realized, the problem of wind abandoning and light abandoning is solved, and peak regulation, off-peak power utilization, clean heat supply and the like of a thermal power plant are realized.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.