A supercritical carbon dioxide power generation coaxial integrated device and a displacement energy storage method

Abstract

The present invention discloses a coaxial integrated device for supercritical carbon dioxide power generation and a replacement energy storage method, including a turbine, a compressor and an inspiration integrated motor, wherein the turbine, the compressor and the inspiration integrated motor are coaxially integrated, an overspeed clutch is arranged between the turbine and the compressor, and a gearbox is arranged between the compressor and the inspiration integrated motor, wherein the inspiration integrated motor acts as a motor in the startup phase and generates electricity as a generator in the operation phase; the high-pressure side of the turbine and the high-pressure side of the compressor are cyclically connected to the high-pressure storage circuit equipment; the low-pressure side of the turbine and the low-pressure side of the compressor are cyclically connected to the low-pressure storage circuit equipment. The present invention saves the cost and operating cost of the compressor motor and can effectively achieve the purpose of energy storage and load regulation.

Description

Technical Field

[0001] The present invention relates to the technical field of supercritical carbon dioxide cycle power generation, and particularly relates to a supercritical carbon dioxide power generation coaxial integrated device and a displacement energy storage method. Background Art

[0002] At present, the circulating working medium of large power plants worldwide is steam. However, with the development of technology, people have gradually found that using supercritical carbon dioxide as the circulating working medium has advantages such as high cycle efficiency, compact equipment structure, and small initial capital investment within a certain power range. Therefore, the supercritical carbon dioxide cycle power generation system and its energy storage system are a very promising cycle method. Under the existing technical conditions, how to further improve the operation efficiency and safety of carbon dioxide cycle power generation through the layout of equipment and systems is the key and difficulty in this field currently. Summary of the Invention

[0003] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a supercritical carbon dioxide power generation coaxial integrated device and a displacement energy storage method. By coaxially arranging the turbine, compressor, and starting integrated motor in carbon dioxide cycle power generation, where the starting integrated motor acts as a motor during the starting stage and as a generator during the operation stage, the cost and operating cost of the compressor motor are saved; through the face-to-face arrangement of the high-pressure sides of the compressor and the turbine, the axial thrust is mutually offset, reducing the load on the thrust bearing; at the same time, by setting high- and low-pressure liquid storage tanks in the circulation loop, and storing working medium in the high-pressure liquid tank or discharging working medium into the low-pressure liquid tank according to the change of electricity price or power generation load, the purpose of energy storage and load regulation is achieved.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A supercritical carbon dioxide power generation coaxial integrated device includes a turbine 1, a compressor 3, and a starting integrated motor 5. The turbine 1, the compressor 3, and the starting integrated motor 5 are arranged in a coaxial integrated manner. An overspeed clutch 2 is arranged between the turbine 1 and the compressor 3, and a gearbox 4 is arranged between the compressor 3 and the starting integrated motor 5. The starting integrated motor 5 acts as a motor during the starting stage and generates electricity as a generator during the operation stage;

[0006] The high-pressure side of the turbine 1 is connected to the high-pressure storage loop equipment on the high-pressure side of the compressor 3;

[0007] The low-pressure side of the turbine 1 is connected to each equipment of the low-pressure storage loop on the low-pressure side of the compressor 3.

[0008] The high-pressure side of the turbine 1 and the high-pressure side of the compressor 3 are arranged face to face.

[0009] During the system startup phase, when the speed of the turbine 1 is lower than that of the compressor 3, the overrunning clutch 2 disengages; during the unit operation phase, when the speed of the turbine 1 is higher than that of the compressor 3, the overrunning clutch 2 engages; the overrunning clutch 2 can withstand axial thrust.

[0010] The high-pressure storage loop equipment includes a high-pressure storage loop inlet regulating valve 8, a high-pressure storage loop inlet check valve 9, a high-pressure storage loop cooler 10, a high-pressure storage loop liquid storage tank 11, a high-pressure storage loop outlet heater 12, a high-pressure storage loop outlet check valve 13, and a high-pressure storage loop outlet regulating valve 14 connected in sequence. The inlet of the high-pressure storage loop inlet regulating valve 8 is connected to the high-pressure side of the compressor 3, and the outlet of the high-pressure storage loop outlet regulating valve 14 is connected to the high-pressure side of the turbine 1. A main loop heater 6 is directly connected between the inlet of the high-pressure storage loop inlet regulating valve 8 and the outlet of the high-pressure storage loop outlet regulating valve 14.

[0011] Each device of the low-pressure storage loop includes a low-pressure storage loop inlet regulating valve 15, a low-pressure storage loop inlet check valve 16, a low-pressure storage loop cooler 17, a low-pressure storage loop liquid storage tank 18, a low-pressure storage loop outlet heater 19, a low-pressure storage loop outlet check valve 20, and a low-pressure storage loop outlet regulating valve 21 connected in sequence. Each device of the low-pressure storage loop is arranged in parallel with the main loop cooler 7.

[0012] A displacement energy storage method for a supercritical carbon dioxide power generation coaxial integrated device includes the following steps;

[0013] During low electricity price periods or when it is necessary to reduce the power generation load, the low-pressure storage loop outlet heater 19, the low-pressure storage loop outlet regulating valve 21, the high-pressure storage loop inlet regulating valve 8, and the high-pressure storage loop cooler 10 are opened in sequence, the power of the main loop heater 6 is reduced, and at the same time, the power generation load of the inspiration integrated motor 5 is reduced, and the speeds of the turbine 1, the compressor 3, and the inspiration integrated motor 5 are kept constant. The pressure of the low-pressure storage loop liquid storage tank 18 is increased and then stored in the high-pressure storage loop liquid storage tank 11.

[0014] During high electricity price periods or when it is necessary to increase the power generation load, the high-pressure storage loop outlet heater 12, the high-pressure storage loop outlet regulating valve 14, the low-pressure storage loop inlet regulating valve 15, and the low-pressure storage loop cooler 17 are opened in sequence, the power of the main loop heater 6 is increased, and at the same time, the power generation load of the inspiration integrated motor 5 is increased, and the speeds of the turbine 1, the compressor 3, and the inspiration integrated motor 5 are kept constant. The storage in the high-pressure storage loop liquid storage tank 11 is discharged to the low-pressure storage loop liquid storage tank 18 through the main loop work.

[0015] The integrated turbine and motor 5 is provided with a frequency converter speed regulation system. During the start-up stage, soft start is adopted by the frequency converter. When the speed of the turbine 1 is higher than that of the compressor 3, the overrunning clutch 2 is in the engaged state, the frequency converter exits, and the unit enters the normal operation stage. The turbine 1 drives the compressor 3 and the integrated turbine and motor 5 to do work, thereby reducing the energy loss of the drive motor of the compressor 3 and the frequency conversion speed regulation system.

[0016] Advantages of the present invention:

[0017] The supercritical carbon dioxide cycle turbine power generation and compression coaxial integrated layout method and the high and low pressure liquid tank replacement type energy storage system of the present invention have the advantages of small axial thrust, saving infrastructure equipment investment, energy storage at low electricity prices, and increasing power generation at high electricity prices, etc., and have strong practicability and high system operation efficiency. Description of the drawings

[0018] Figure 1 It is a schematic structural diagram of the system of the present invention. Detailed implementation manners

[0019] The present invention will be further described in detail below with reference to the drawings.

[0020] As Figure 1 shown: Supercritical carbon dioxide cycle power generation, as a new power generation technology, has the advantages of high cycle efficiency, compact equipment structure, and small initial infrastructure investment within a certain power range. Therefore, the supercritical carbon dioxide cycle power generation system and its energy storage system are a very promising cycle method.

[0021] 1) The turbine 1, the compressor 3 and the integrated turbine and motor 5 adopt a coaxial layout method. The overrunning clutch 2 is arranged between the turbine 1 and the compressor 3, and the gearbox 4 is arranged between the compressor 3 and the integrated turbine and motor 5; by adopting the method of arranging the high-pressure side of the turbine 1 face to face with the high-pressure side of the compressor 3, the axial forces of each other are offset, the axial thrust of the unit is reduced, the load of the thrust bearing is reduced, and the structural safety of the unit is improved;

[0022] 2) In this system, the generator and the motor adopt the integrated turbine and motor 5. During the start-up stage, it acts as a motor to provide power for the compressor 3. At this time, the speed of the turbine 1 is lower than that of the compressor 3, the overrunning clutch 2 is in the disengaged state, and the integrated turbine and motor 5 does not do work on the turbine 1; during the operation stage, the high-temperature and high-pressure working medium drives the turbine 1 to do work, the speed of the turbine 1 is higher than that of the compressor 3, at this time the overrunning clutch 2 is in the engaged state, the turbine 1 drives the compressor 3 and the integrated turbine and motor 5 to rotate and do work externally, combining the generator and the motor into one, saving the initial investment of the equipment;

[0023] 3) During the unit startup phase, the frequency converter serves as a speed control system to provide a soft startup mode for the compressor 3. When the speed of the turbine 1 is higher than that of the compressor 3, the overrunning clutch 2 engages, and the frequency converter exits. The unit enters the normal operation phase, where the turbine 1 drives the compressor 3 and the integrated motor-generator 5 to rotate and perform external work, thereby reducing the energy loss of the drive motor of the compressor 3 and the variable frequency speed control system.

[0024] 4) When the unit is in the normal operation state, the unit operates at a constant speed. When power generation load adjustment is required, only the inlet and outlet regulating valves, heaters, and coolers of the high and low-pressure storage loop systems need to be opened or closed, injecting high-pressure working fluid into the high-pressure storage loop liquid storage tank 11 or discharging the working fluid to the low-pressure storage loop liquid storage tank 18, and adjusting the power of the main loop heater 6 and the power generation load of the integrated motor-generator 5, so as to achieve the purpose of load adjustment of the unit at a constant speed state.

[0025] For the above supercritical carbon dioxide power generation coaxial integrated equipment, its principles during startup and operation are as follows:

[0026] For the existing layout of the carbon dioxide power generation system, first, a high-pressure storage loop device (storage loop inlet regulating valve 8, storage loop inlet check valve 9, storage loop cooler 10, storage loop liquid storage tank 11, storage loop outlet heater 12, storage loop outlet check valve 13, storage loop outlet regulating valve 14) is connected in parallel to the inlet and outlet pipelines of the main loop heater 6; second, each device of the low-pressure storage loop (low-pressure storage loop inlet regulating valve 15, low-pressure storage loop inlet check valve 16, low-pressure storage loop cooler 17, low-pressure storage loop liquid storage tank 18, low-pressure storage loop outlet heater 19, low-pressure storage loop outlet check valve 20, low-pressure storage loop outlet regulating valve 21) is connected in parallel to the inlet and outlet pipelines of the main loop cooler 7; third, the turbine 1, compressor 3, and integrated motor-generator 5 are arranged coaxially, with an overrunning clutch 2 arranged between the turbine 1 and the compressor 3, and a gearbox 4 arranged between the compressor 3 and the integrated motor-generator 5.

[0027] When the unit starts up, power is supplied to the integrated motor-generator 5 through the variable frequency speed control system. The integrated motor-generator 5 drives the compressor 3 to start and accelerate slowly. After the carbon dioxide working fluid passes through the compressor 3, the main loop heater 6, the turbine 1, and the main loop cooler 7 in sequence, it returns to the inlet of the compressor 3. At the same time, by opening the low-pressure storage loop outlet heater 19 and the low-pressure storage loop outlet check valve 20, working fluid is continuously replenished into the main loop system. At this time, although there is working fluid driving the turbine 1 to operate, the speed of the turbine 1 is lower than that of the compressor 3, and the overrunning clutch 2 is in the disengaged state. That is, at this time, the integrated motor-generator 5 only drives the compressor 3 to do work as a motor.

[0028] With the increase in the rotational speed of the compressor 3 and the power of the main circuit heater 6, the temperature and pressure of the carbon dioxide working fluid at the inlet of the turbine 1 gradually increase. At the same time, the rotational speed and output power of the turbine 1 also increase. When the rotational speed of the turbine 1 is higher than that of the compressor 3, the overrunning clutch 2 engages, and the turbine 1 drives the compressor 3 and the integrated starting and generating motor 5 to rotate. At this time, the integrated starting and generating motor 5 starts to output electric power to the outside as a generator.

[0029] When the unit is at the designed power generation load, the inlet regulating valve 8 of the high-pressure storage circuit, the cooler 10 of the high-pressure storage circuit, the outlet heater 12 of the high-pressure storage circuit, the outlet regulating valve 14 of the high-pressure storage circuit, the inlet regulating valve 15 of the low-pressure storage circuit, the cooler 17 of the low-pressure storage circuit, the outlet heater 19 of the low-pressure storage circuit, and the outlet regulating valve 21 of the low-pressure storage circuit are all in the closed or out-of-service state. At this time, the carbon dioxide working fluid is compressed by the compressor 3 to increase the pressure, heated by the main circuit heater 6 to increase the temperature, expands and does work externally by the turbine 1, and is cooled by the main circuit cooler 7 and then returns to the inlet of the compressor 3 to complete a work cycle.

[0030] During the low electricity price period, or when the unit further reduces the power generation load based on the designed operating conditions and keeps the rotational speeds of the turbine 1, the compressor 3, and the integrated starting and generating motor 5 constant, the system working fluid is still in the normal circulation state. The outlet heater 19 of the low-pressure storage circuit, the outlet regulating valve 21 of the low-pressure storage circuit, the inlet regulating valve 8 of the high-pressure storage circuit, and the cooler 10 of the high-pressure storage circuit are opened in sequence to reduce the power generation load of the integrated starting and generating motor 5 and the power of the main circuit heater 6, and the working fluid in the liquid storage tank 18 of the low-pressure storage circuit is pressurized and stored in the liquid storage tank 11 of the high-pressure storage circuit.

[0031] During the high electricity price period, or when the unit needs to further increase the power generation load based on the designed operating conditions and keeps the rotational speeds of the turbine 1, the compressor 3, and the integrated starting and generating motor 5 constant, the system working fluid is still in the normal circulation state. The outlet heater 12 of the high-pressure storage circuit, the outlet regulating valve 14 of the high-pressure storage circuit, the inlet regulating valve 15 of the low-pressure storage circuit, and the cooler 17 of the low-pressure storage circuit are opened in sequence to increase the power generation load of the integrated starting and generating motor 5 and the power of the main circuit heater 6, keep the rotational speeds of the turbine 1, the compressor 3, and the integrated starting and generating motor 5 constant, and release the working fluid stored in the liquid storage tank 11 of the high-pressure storage circuit to the liquid storage tank 18 of the low-pressure storage circuit after doing work through the main circuit. At the same time, the purpose of increasing the power generation of the unit is achieved.

Claims

1. A replacement energy storage method for a supercritical carbon dioxide power generation coaxial integrated device, characterized in that, this method is realized through a supercritical carbon dioxide power generation coaxial integrated device, which includes a turbine (1), a compressor (3) and a motor-generator integrated motor (5). The turbine (1), the compressor (3) and the motor-generator integrated motor (5) are arranged in a coaxial integrated manner. An overrunning clutch (2) is arranged between the turbine (1) and the compressor (3), and a gearbox (4) is arranged between the compressor (3) and the motor-generator integrated motor (5). Among them, the motor-generator integrated motor (5) acts as a motor during the start-up stage and generates electricity as a generator during the operation stage; The high-pressure side of the turbine (1) is connected to the high-pressure storage loop device on the high-pressure side of the compressor (3); The low-pressure side of the turbine (1) is connected to each device of the low-pressure storage loop on the low-pressure side of the compressor (3); The method includes the following steps; During low electricity price periods or when it is necessary to reduce the power generation load, the outlet heater (19) of the low-pressure storage loop, the outlet regulating valve (21) of the low-pressure storage loop, the inlet regulating valve (8) of the high-pressure storage loop, and the cooler (10) of the high-pressure storage loop are opened in sequence to reduce the power of the main loop heater (6). At the same time, the power generation load of the motor-generator integrated motor (5) is reduced, and the speeds of the turbine (1), the compressor (3) and the motor-generator integrated motor (5) are kept constant. The liquid in the low-pressure storage loop liquid storage tank (18) is pressurized and stored in the high-pressure storage loop liquid storage tank (11); During high electricity price periods or when it is necessary to increase the power generation load, the outlet heater (12) of the high-pressure storage loop, the outlet regulating valve (14) of the high-pressure storage loop, the inlet regulating valve (15) of the low-pressure storage loop, and the cooler (17) of the low-pressure storage loop are opened in sequence to increase the power of the main loop heater (6). At the same time, the power generation load of the motor-generator integrated motor (5) is increased, and the speeds of the turbine (1), the compressor (3) and the motor-generator integrated motor (5) are kept constant. The liquid stored in the high-pressure storage loop liquid storage tank (11) is discharged to the low-pressure storage loop liquid storage tank (18) after doing work through the main loop; The motor-generator integrated motor (5) is provided with a frequency converter speed regulation system. During the start-up stage, soft start of the frequency converter is adopted. When the speed of the turbine (1) is higher than the speed of the compressor (3), the overrunning clutch (2) is in the engaged state, and the frequency converter exits. The unit enters the normal operation stage, and the turbine (1) drives the compressor (3) and the motor-generator integrated motor (5) to do work, thereby reducing the energy loss of the compressor (3) drive motor and the frequency conversion speed regulation system; The high-pressure storage loop equipment includes a high-pressure storage loop inlet regulating valve (8), a high-pressure storage loop inlet check valve (9), a high-pressure storage loop cooler (10), a high-pressure storage loop liquid storage tank (11), a high-pressure storage loop outlet heater (12), a high-pressure storage loop outlet check valve (13), and a high-pressure storage loop outlet regulating valve (14) that are connected in sequence. The inlet of the high-pressure storage loop inlet regulating valve (8) is connected to the high-pressure side of the compressor (3), and the outlet of the high-pressure storage loop outlet regulating valve (14) is connected to the high-pressure side of the turbine (1). A main loop heater (6) is directly connected between the inlet of the high-pressure storage loop inlet regulating valve (8) and the outlet of the high-pressure storage loop outlet regulating valve (14); Each device of the low-pressure storage loop includes a low-pressure storage loop inlet regulating valve (15), a low-pressure storage loop inlet check valve (16), a low-pressure storage loop cooler (17), a low-pressure storage loop liquid storage tank (18), a low-pressure storage loop outlet heater (19), a low-pressure storage loop outlet check valve (20), and a low-pressure storage loop outlet regulating valve (21) that are connected in sequence. Each device of the low-pressure storage loop is arranged in parallel with the main loop cooler (7); The high-pressure side of the turbine (1) and the high-pressure side of the compressor (3) are arranged face to face; During the startup stage of the unit, when the speed of the turbine (1) is lower than the speed of the compressor (3), the overrunning clutch (2) disengages; during the operation stage of the unit, when the speed of the turbine (1) is higher than the speed of the compressor (3), the overrunning clutch (2) engages; the overrunning clutch (2) can withstand axial thrust.

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