A supercritical carbon dioxide heating and power generation system and its operation method

Abstract

The present invention belongs to the technical field of supercritical carbon dioxide cycle power generation, and discloses a supercritical carbon dioxide heating and power generation system and an operating method thereof, comprising a heating compressor, a turbine, an inspiration integrated motor and a power generation compressor coaxially arranged in sequence; the turbine is arranged away from the excitation side of the inspiration integrated motor, and the turbine comprises a low-pressure turbine and a high-pressure turbine coaxially and arranged back to back; wherein, the low-pressure turbine is connected to the heating compressor, and the high-pressure turbine is connected to the inspiration integrated motor; the present invention arranges the inspiration integrated motor, the high-pressure turbine and the low-pressure turbine coaxially, and arranges the heating compressor and the power generation compressor at both ends of the system, so as to realize the use of a set of host equipment to simultaneously meet the output requirements under heating and power generation conditions, and ensures the efficient operation of the system under heating conditions and power generation conditions without the need to configure two sets of host equipment at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of supercritical carbon dioxide cycle power generation, and in particular relates to a supercritical carbon dioxide heat supply and power generation system and an operation method thereof. Background Art

[0002] Supercritical carbon dioxide power generation technology uses supercritical carbon dioxide as a circulating working fluid, and has the advantages of high circulation efficiency, compact equipment structure, and small initial infrastructure investment. In a supercritical carbon dioxide power generation system, it is usually required to be able to meet both winter heating conditions and summer power generation conditions. That is, under heating conditions, the system is required to have a large heat supply, and under power generation conditions, the system is required to have the highest possible power generation efficiency.

[0003] At present, in order to enable the system to simultaneously meet the heating conditions in winter and the power generation conditions in summer, its thermal power under the heating conditions is much greater than the thermal power under the power generation conditions, and the system main gas flow and main gas pressure under the heating conditions are generally also much greater than the system main gas flow and main gas pressure under the power generation conditions; therefore, the existing supercritical carbon dioxide power generation system is usually equipped with two sets of main equipment to simultaneously meet the needs of heating conditions in winter and power generation conditions in summer; however, when the supercritical carbon dioxide power generation system is equipped with two sets of main equipment, there are generally technical problems such as increased difficulty in system integration and coordinated control, and increased initial investment costs. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention provides a supercritical carbon dioxide heating and power generation system and an operation method thereof to solve the technical problems that are commonly encountered when a supercritical carbon dioxide power generation system is equipped with two sets of host equipment, such as increased difficulty in system integration and coordinated control, and increased initial investment costs.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a supercritical carbon dioxide heating and power generation system, comprising a heating compressor, a turbine, an integrated heating motor and a power generation compressor which are coaxially arranged in sequence;

[0007] The turbine is arranged away from the excitation side of the integrated inspiration motor, and the turbine includes a low-pressure turbine and a high-pressure turbine that are coaxial and arranged back to back; wherein, the low-pressure turbine is connected to the heating compressor, and the high-pressure turbine is connected to the integrated inspiration motor.

[0008] Furthermore, the matching design process of the supercritical carbon dioxide heating and power generation system is as follows:

[0009] The turbine is selected, designed, and calibrated using the design values ​​of the system's main gas pressure and main gas flow rate under heating conditions as design conditions and the design values ​​of the system's main gas pressure and main gas flow rate under power generation conditions as calibration conditions. The process for determining the design values ​​of the system's main gas pressure and main gas flow rate under power generation conditions is as follows:

[0010] Based on the main gas pressure and main gas flow of the system under heating conditions, the turbine is selected and designed to obtain a design and selection result of geometric parameters of the turbine;

[0011] Drawing a turbine pressure-flow performance curve based on the turbine geometric parameter design and selection results;

[0012] Taking the system power generation under power generation conditions as the target parameter and the system main gas pressure and main gas flow rate as floating parameters, draw the system main gas pressure-main gas flow rate relationship curve under power generation conditions;

[0013] According to the turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under power generation conditions, the design values ​​of the system main gas pressure and main gas flow under power generation conditions are obtained.

[0014] Furthermore, the process of obtaining design values ​​of the system's main gas pressure and main gas flow under power generation conditions based on the turbine pressure-flow performance curve and the system's main gas pressure-main gas flow relationship curve under power generation conditions includes:

[0015] A two-dimensional rectangular coordinate system is constructed with the pressure parameter as the horizontal axis and the flow parameter as the vertical axis to obtain a pre-constructed two-dimensional rectangular coordinate system;

[0016] The turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under power generation conditions are simultaneously plotted in a pre-constructed two-dimensional rectangular coordinate system, and the coordinates of the intersection of the turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under power generation conditions are solved to obtain the design values ​​of the system main gas pressure and main gas flow under power generation conditions.

[0017] Furthermore, it also includes a first gearbox and a second gearbox; the first gearbox is arranged between the heating compressor and the low-pressure turbine, and the second gearbox is arranged between the integrated electric motor and the power generation compressor.

[0018] Furthermore, the heating compressor, the low-pressure turbine and the high-pressure turbine are provided with a unified expansion and sliding system; wherein, the expansion dead points of the heating compressor, the low-pressure turbine and the high-pressure turbine are all provided at the shaft connection between the high-pressure turbine and the integrated motor.

[0019] Furthermore, the heating compressor, the low-pressure turbine and the high-pressure turbine all expand toward the free end of the heating compressor.

[0020] Furthermore, the rated speeds of the low-pressure turbine and the high-pressure turbine are the same as the rated speed of the integrated inspiration motor.

[0021] Furthermore, the power supply terminal of the said inspiration integrated motor is connected to the power grid, and a frequency converter and a bypass switch are also provided between the said inspiration integrated motor and the power grid; wherein the frequency converter and the bypass switch are provided in parallel.

[0022] The present invention also provides an operating method of a supercritical carbon dioxide heating and power generation system, comprising a system startup phase and an operating phase;

[0023] During the system startup phase, the inspiration integrated motor starts at a variable speed; during the operation phase, the inspiration integrated motor runs at a rated speed.

[0024] Furthermore, the operation phase includes heating conditions and power generation conditions;

[0025] Under heating conditions, the power generation compressor is disconnected from the ignition integrated unit, and the heating compressor operates normally;

[0026] In the power generation condition, the heating compressor is disconnected from the low-pressure turbine, and the power generation compressor operates normally.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The supercritical carbon dioxide heating and power generation system provided by the present invention arranges the inspiration integrated motor, high-pressure turbine and low-pressure turbine coaxially, and arranges the heating compressor and the power generation compressor at both ends of the system, so that the output requirements under heating and power generation conditions can be simultaneously met by using one set of main equipment, and the efficient operation of the system under heating and power generation conditions can be guaranteed without configuring two sets of main equipment at the same time; the various devices in the system are arranged coaxially in sequence, which reduces the number of devices and the connectors and pipelines between the devices, making the system structure more compact, greatly reducing the difficulty of system integration and coordinated control, and at the same time can effectively reduce the initial investment and effectively improve the engineering economy of the unit; among them, the low-pressure turbine and the high-pressure turbine are arranged coaxially and back-to-back, which can automatically adjust the output power according to the load demand, ensure the stable working state of the compressor and the inspiration integrated motor, realize load balancing and power regulation, and further improve the operating efficiency of the system; secondly, the application of the inspiration integrated motor enables the system to flexibly switch between power generation and motor modes, thereby improving the flexibility and adaptability of the system.

[0029] Furthermore, the design values ​​of the system's main gas pressure and main gas flow under heating conditions are used as design conditions, and the design values ​​of the system's main gas pressure and main gas flow under power generation conditions are used as verification conditions, so as to perform load matching design verification on the turbine under both heating and power generation conditions, so that it can simultaneously and efficiently meet the requirements of efficient, safe and stable operation of both heating and power generation conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 A schematic diagram of the structure of a supercritical carbon dioxide heating and power generation system provided in an embodiment;

[0032] Figure 2 This is a shafting arrangement diagram for heating operation in the embodiment;

[0033] Figure 3 This is a shafting arrangement diagram for power generation operation in the embodiment;

[0034] Figure 4 This is a schematic diagram of the electrical principle of the supercritical carbon dioxide heating and power generation system described in the embodiment;

[0035] Figure 5 Schematic diagram of the matching design principle of the supercritical carbon dioxide heating and power generation system in the embodiment.

[0036] Among them, 1 is the heating compressor, 2 is the low-pressure turbine, 3 is the high-pressure turbine, 4 is the inspiration motor, 5 is the generator compressor, 6 is the first gearbox, 7 is the second gearbox, 8 is the inverter, 9 is the bypass switch, and 10 is the vacuum circuit breaker. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions, and beneficial effects solved by this application more clearly understood, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application; it is obvious that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of this application.

[0038] The present invention provides a supercritical carbon dioxide heating and power generation system, comprising a heating compressor 1, a turbine, an integrated inspiration motor 4 and a power generation compressor 5 arranged coaxially in sequence; the turbine is arranged away from the excitation side of the integrated inspiration motor 4, and the turbine includes a low-pressure turbine 2 and a high-pressure turbine 3 coaxially and arranged back to back; wherein, the low-pressure turbine 2 is connected to the heating compressor 1, and the high-pressure turbine 3 is connected to the integrated inspiration motor 4.

[0039] The matching design process of the supercritical carbon dioxide heating and power generation system is as follows:

[0040] The turbine is selected, designed and verified with the design values ​​of the system's main gas pressure and main gas flow under heating conditions as design conditions and with the design values ​​of the system's main gas pressure and main gas flow under power generation conditions as verification conditions. The process of determining the design values ​​of the system's main gas pressure and main gas flow under power generation conditions comprises: selecting and designing the turbine based on the system's main gas pressure and main gas flow under heating conditions to obtain a design and selection result of the turbine's geometric parameters; drawing a turbine pressure-flow performance curve based on the design and selection result of the turbine's geometric parameters; drawing a system main gas pressure-main gas flow curve under power generation conditions with the system's power generation under power generation conditions as a target parameter and the system's main gas pressure and main gas flow as floating parameters; and obtaining the design values ​​of the system's main gas pressure and main gas flow under power generation conditions based on the turbine pressure-flow performance curve and the system's main gas pressure-main gas flow curve under power generation conditions.

[0041] The supercritical carbon dioxide heating and power generation system described in the present invention arranges the heating compressor, turbine, integrated inspiration motor and power generation compressor coaxially in sequence, wherein the turbine adopts a high-pressure turbine and a low-pressure head arranged back to back, thereby realizing a compact and efficient design of the system, and meeting the heating and power generation operating requirements of the system without the need to design two sets of independent main equipment; secondly, the matching design process comprehensively considers the two operating conditions of heating and power generation, and determines the design values ​​of the main gas pressure and main gas flow under the power generation condition through turbine selection design, drawing the pressure-flow curve, and optimizing with the power generation power as the target parameter, and verifies the turbine selection design results with the design values ​​of the main gas pressure and main gas flow under the power generation condition as the verification condition, thereby ensuring the efficient and stable operation of the system under different operating conditions.

[0042] The following further explains the supercritical carbon dioxide heating and power generation system provided by the present invention with some specific embodiments:

[0043] Example

[0044] As attached Figure 1As shown, this embodiment provides a supercritical carbon dioxide heating and power generation system, including a heating compressor 1, a first gearbox 6, a low-pressure turbine 2, a high-pressure turbine 3, an integrated inspiration motor 4, a second gearbox 7 and a power generation compressor 5 arranged coaxially in sequence.

[0045] In this embodiment, the heating compressor 1, the first gearbox 6, the low-pressure turbine 2, the high-pressure turbine 3 and the inspiration integrated machine 4 are coaxially connected in sequence to form a heating working condition shaft system, as shown in the attached figure. Figure 2 As shown; specifically, the input end of the heating compressor 1 is connected to the output end of the first gearbox 6, and the input end of the first gearbox 6 is connected to the output end of the low-pressure turbine 2; wherein, the first gearbox 6 and the heating compressor 1 are connected by a first coupling; the input end of the low-pressure turbine 2 is connected to the output end of the high-pressure turbine 3, and the input end of the high-pressure turbine 3 is connected to one end of the excitation side of the inspiration integrated motor 4 away from the excitation side.

[0046] In the heating working condition shaft system, the low-pressure turbine 2 and the high-pressure turbine 3 are arranged back to back to offset the axial force; the rated speeds of the low-pressure turbine 2 and the high-pressure turbine 3 are the same as the rated speed of the inspiration integrated motor 4.

[0047] In this embodiment, the low-pressure turbine 2, the high-pressure turbine 3, the inspiration integrated motor 4, the second gearbox 7 and the power generation compressor 5 are coaxially connected in sequence to form a power generation working condition shaft system, as shown in the attached figure. Figure 3 As shown; specifically, one end of the high-pressure turbine 3 is connected to the low-pressure turbine 2, the other end of the high-pressure turbine 3 is connected to one end of the excitation side of the inspiration integrated motor 4 away from the excitation side, one end of the excitation side of the inspiration integrated motor 4 is connected to the input end of the second gearbox 7, and the output end of the second gearbox 7 is connected to the input end of the power generation compressor 5; wherein, the second gearbox 7 and the power generation compressor 5 are connected by a second coupling.

[0048] In this embodiment, the heating compressor 1, the low-pressure turbine 2 and the high-pressure turbine 3 are provided with a unified expansion and sliding system to ensure that the cylinders of the low-pressure turbine 2 and the high-pressure turbine 3 expand smoothly due to heat; wherein, the expansion dead points of the heating compressor 1, the low-pressure turbine 2 and the high-pressure turbine 3 are all set at the shaft connection between the high-pressure turbine 3 and the integrated inspiration motor 4; the heating compressor 1, the low-pressure turbine 2 and the high-pressure turbine 3 expand uniformly toward the free end of the heating compressor 1.

[0049] In this embodiment, the inspiration integrated motor 4 adopts an inspiration integrated synchronous excitation generator, and the inspiration integrated synchronous excitation generator is equipped with a 50% rated power frequency converter; in the system startup phase, the inspiration integrated motor 4 acts as an electric motor, and establishes initial pressure for the system in a variable speed startup mode; in the system operation phase, the inspiration integrated motor 4 acts as a generator, and operates at a rated speed; the power supply end of the inspiration integrated motor 4 is connected to the power grid, and a frequency converter 8, a bypass switch 9 and a vacuum circuit breaker 10 are also connected between the power supply end of the inspiration integrated motor 4 and the power grid, as shown in the attached figure. Figure 4 As shown; wherein, the access method of the frequency converter 8, the bypass switch 9 and the vacuum circuit breaker 10 is specifically as follows: the frequency converter 8 and the bypass switch 9 are connected in parallel and then connected in series with the vacuum circuit breaker 10, and the vacuum circuit breaker 10 is set close to the side of the power grid.

[0050] In this embodiment, a trolley or slide device is provided at the generator compressor 5; the trolley or slide device is used to move the generator compressor 5 so as to remove the rotor of the integrated inspiration motor 4 for maintenance; specifically, before the rotor is removed for maintenance of the integrated inspiration motor 4, the trolley or slide device is used to move the generator compressor 5 as a whole to a preset position to provide sufficient maintenance space; after the maintenance is completed, the trolley or slide device is used to move the generator compressor 5 back to the installation position of the generator compressor.

[0051] In this embodiment, the first gearbox 6 is arranged between the heating compressor 1 and the low-pressure turbine 2, and the second gearbox 7 is arranged between the integrated motor 4 and the power generation compressor 5, so as to utilize the first gearbox 6 and the second gearbox 7 to increase the speed of the heating compressor 1 and the power generation compressor 5 respectively.

[0052] Matching design process:

[0053] The supercritical carbon dioxide heating and power generation system described in this embodiment undergoes a compatibility design process, using the design values ​​of the system's main gas pressure and main gas flow rate under heating conditions as the design operating conditions, and the design values ​​of the system's main gas pressure and main gas flow rate under power generation conditions as the verification operating conditions, to select, design, and verify the turbine. The selection, design, and verification process for a high-pressure turbine is described below as an example:

[0054] Step 1. Based on the design values ​​of the main gas pressure and main gas flow of the system under the heating condition as the design condition, the high-pressure turbine is selected and designed to obtain the geometric parameter design selection results of the high-pressure turbine; wherein the geometric parameter design selection results of the high-pressure turbine include the speed, number of stages, impeller outer diameter, number of blades, blade height, and inlet and outlet installation angles of the high-pressure turbine.

[0055] Step 2: Based on the geometric parameter design and selection results of the high-pressure turbine, draw the high-pressure turbine pressure-flow performance curve; wherein, the high-pressure turbine pressure-flow performance curve is the variable operating condition performance curve of the high-pressure turbine, that is, the inlet pressure-inlet flow relationship curve of the high-pressure turbine; it should be noted that when the system back pressure remains unchanged, the inlet pressure and inlet flow of the high-pressure turbine 2 are positively correlated.

[0056] Step 3: Using the system power generation under power generation conditions as the target parameter and the system main gas pressure and main gas flow rate as floating parameters, draw a system main gas pressure-main gas flow rate relationship curve under power generation conditions. It should be noted that when the system power generation remains unchanged, the system main gas pressure-main gas flow rate relationship curve under power generation conditions is inversely correlated.

[0057] Step 4: Determine the design values ​​of the system's main gas pressure and main gas flow under power generation conditions based on the high-pressure turbine pressure-flow performance curve and the system's main gas pressure-main gas flow curve under power generation conditions. The specific process is as follows:

[0058] A two-dimensional rectangular coordinate system is constructed with the pressure parameter as the horizontal axis and the flow parameter as the vertical axis to obtain a pre-constructed two-dimensional rectangular coordinate system; the high-pressure turbine pressure-flow performance curve and the system main gas pressure-main gas flow curve under power generation conditions are simultaneously plotted in the pre-constructed two-dimensional rectangular coordinate system, and the coordinates of the intersection of the high-pressure turbine pressure-flow performance curve and the system main gas pressure-main gas flow curve under power generation conditions are solved to obtain the design values ​​of the main gas pressure and main gas flow of the system under power generation conditions.

[0059] It should be noted that since the high-pressure turbine pressure-flow performance curve and the system main gas pressure-main gas flow curve under power generation conditions have opposite changing trends, there must be a unique and stable intersection point in the same two-dimensional rectangular coordinate system, as shown in the attached figure. Figure 5 As shown; wherein, the horizontal coordinate of the intersection is the design value of the main gas pressure of the system under the power generation condition, and the vertical coordinate of the intersection is the design value of the main gas flow of the system under the power generation condition.

[0060] Step 5. Based on the geometric parameter design and selection results of the high-pressure turbine, obtain the design and selection results of the high-pressure turbine; use the design values ​​of the main gas pressure and main gas flow of the system under the power generation condition as the verification condition, and verify the design and selection results of the high-pressure turbine to verify the performance of the design and selection results of the high-pressure turbine under the verification condition; among them, if the performance of the design and selection results of the high-pressure turbine under the verification condition is in the high-efficiency performance zone, then output the design and selection results of the high-pressure turbine.

[0061] It should be noted that since the turbine power under heating conditions is greater than that under power generation conditions, in order to save equipment costs and ensure that the turbine can operate efficiently under both heating and power generation conditions, in this embodiment, the flow and pressure parameters of the system under heating conditions are used as design parameters to design and select the high-pressure turbine and the low-pressure turbine; after the geometric parameters of the turbine are finalized, the flow-pressure performance curve of the system with constant back pressure, that is, the turbine pressure-flow performance curve, can be obtained; at the same time, when the power generation power of the system remains unchanged, there is also a quantitative relationship between the main gas flow and the main gas pressure, that is, the system main gas pressure-main gas flow curve under power generation conditions can be obtained; by coupling and solving the intersection relationship between the turbine pressure-flow performance curve and the system main gas pressure-main gas flow curve under power generation conditions, a unique and stable main gas flow and main gas pressure can be obtained as the design parameters for the power generation condition, and the power generation condition design parameters are used as the verification condition for turbine selection and verification.

[0062] It should also be noted that the selection, design and verification process for the low-pressure turbine is basically the same as the selection, design and verification process for the high-pressure turbine mentioned above, and will not be repeated here.

[0063] Working principle and operation method:

[0064] The supercritical carbon dioxide heating and power generation system described in this embodiment includes a system startup phase and an operation phase during operation; wherein, during the system startup phase, the inspiration integrated motor 4 is started at a variable speed; during the operation phase, the inspiration integrated motor 4 operates at a rated speed; specifically,

[0065] During the startup phase, the system draws power from the power grid, and the inspiration integrated motor 4 is in the motor operation state; the power grid's industrial frequency AC power is converted by the frequency converter 8 and then transmitted to the inspiration integrated motor 4, and the inspiration integrated motor 4 starts at a variable speed and gradually increases the speed; after the system's main gas temperature and main gas pressure gradually rise to meet the turbine rushing conditions, the turbine starts to rush and increase the power, and the current passing through the frequency converter 8 becomes smaller and smaller. At the moment when the current of the frequency converter 8 is reduced to zero, the bypass switch 9 is closed, the frequency converter 8 is shut down, and the inspiration integrated motor 4 switches to the generator operation state and starts to output electrical energy to the power grid.

[0066] During the operation phase, the system's operating conditions include heating conditions and power generation conditions; under the heating condition, the power generation compressor 5 is disconnected from the ignition integrated machine 4, and the heating compressor 1 operates normally; specifically, the second coupling is released, the power generation compressor 5 stops running, and the heating compressor 1 operates; under the power generation condition, the heating compressor 1 is disconnected from the low-pressure turbine 2, and the power generation compressor 5 operates normally; specifically, the first coupling is released, the heating compressor 1 stops running, and the power generation compressor 5 operates; wherein, under the heating condition and the power generation condition, the high-pressure turbine and the low-pressure turbine share the same set of equipment.

[0067] Example description:

[0068] Taking a supercritical carbon dioxide heating and power generation system as an example, the present invention is illustrated as follows:

[0069] Before the matching design, the boundary parameters of the supercritical carbon dioxide heating and power generation system under heating conditions and power generation conditions are shown in Table 1 below.

[0070] Table 1 Boundary parameters of heating and power generation conditions

[0071]

[0072] As can be seen from Table 1, before the matching design, there are large deviations between the heating and power generation conditions in terms of compressor inlet temperature, compressor power, turbine power, and main gas pressure. The thermal power of the system under the heating condition is much greater than that under the power generation condition, and the compressor inlet temperature under the heating condition is much higher than that under the power generation condition. At the same time, the compressor shaft power under the heating condition is nearly four times that under the power generation condition. Therefore, it is impossible to share compressors under the heating and power generation conditions, and the heating compressor and the power generation compressor must be designed and selected separately. Secondly, due to the large power deviation between the heating compressor and the power generation compressor under the heating condition, it is impossible to set up an independent drag turbine for the compressor. Otherwise, the drag turbine power will deviate too much between the heating and power generation conditions and cannot be balanced. Therefore, the compressor shaft system and the turbine shaft system must be arranged coaxially to maintain matching and balance of shaft system power under the two conditions.

[0073] In this example, the inspired integrated motor uses an inspired integrated synchronous excitation generator, which is equipped with a 50% rated power inverter; during the startup phase, the inspired integrated motor acts as an electric motor to establish initial pressure for the unit; during the operation phase, the inspired integrated motor acts as a generator and runs at a rated speed of 3000 rpm; a high-pressure turbine and a low-pressure turbine are arranged on the excitation side away from the inspired integrated motor, and the high-pressure turbine and the low-pressure turbine are arranged back to back to offset the axial force; among them, the rated speed of the high-pressure turbine and the low-pressure turbine is the same as that of the inspired integrated motor, both of which are 3000 rpm.

[0074] Since the excitation-side shaft output power of the helical motor is relatively small, the generator compressor is placed close to the excitation side of the helical motor, and the heating compressor is placed close to the low-pressure turbine. Gearbox speed increasers are installed between the heating compressor and the generator compressor and the drive shaft. Under heating conditions, the coupling on the generator compressor side is released, and only the heating compressor operates. Under power generation conditions, the coupling on the heating compressor side is released, and only the generator compressor operates. The high-pressure turbine and the low-pressure turbine need to meet the processing requirements of both heating and power generation conditions, but they need to be designed for working condition matching. The matching design process is as follows:

[0075] The design values ​​of the main gas pressure and main gas flow of the system under the heating condition are used as the design conditions to select and design the turbine and obtain the selection results of the turbine geometric parameters. After obtaining the selection results of the turbine geometric parameters, the turbine variable operating performance curve with the system back pressure unchanged, that is, the turbine pressure-flow performance curve, is drawn. Then, the power generation power under the power generation condition is used as the target parameter, and the main gas pressure and main gas flow of the system are used as floating parameters to draw the relationship curve between the system main gas pressure and main gas flow when the power generation power is unchanged, that is, the system main gas pressure-main gas flow curve under the power generation condition. The turbine pressure-flow performance curve is compared with the The intersection of the system main gas pressure-main gas flow curve under power generation conditions is the design value of the system main gas pressure and main gas flow under power generation conditions. Since the turbine pressure-flow performance curve and the system main gas pressure-main gas flow curve under power generation conditions have opposite changing trends, there must be a stable intersection between the two. Among them, the pressure of 22.5MPa and the flow rate of 1566t / h at the intersection can be used as the design values ​​of the system main gas pressure and main gas flow under power generation conditions. Finally, the design values ​​of the system main gas pressure and main gas flow under power generation conditions are used as the verification conditions to verify the turbine selected based on the design conditions.

[0076] After the above design and verification process, the design parameters of the system under heating and power generation conditions can be obtained, as shown in Table 2 below.

[0077] Table 2 Comparison of design parameters for heating and power generation conditions

[0078]

[0079] As can be seen from Table 2 above, after matching design and verification, the high-pressure turbine and low-pressure turbine can simultaneously meet the output requirements of heating conditions and power generation conditions. At the same time, the inlet volume flow deviations of the high-pressure turbine and low-pressure turbine under power generation conditions are only -1.7% and -7.3%, respectively, which are extremely small volume flow deviations. Therefore, the high-pressure turbine and low-pressure turbine can maintain high efficiency under power generation conditions.

[0080] The supercritical carbon dioxide heating and power generation system described in the present invention adopts a scheme of coaxial arrangement of an integrated motor with a high-pressure turbine and a low-pressure turbine in terms of shaft system arrangement, and arranges a heating compressor and a power generation compressor at both ends of the system to meet the output requirements of heating and power generation conditions respectively; secondly, by respectively obtaining the flow-pressure curve of the turbine variable condition designed for heating conditions and the flow-pressure curve of the power generation condition system, the flow and pressure at the intersection of the two curves are obtained as the design values ​​of the system main gas pressure-main gas flow curve under the power generation condition; based on the design values ​​of the main gas pressure and main gas flow of the system under the heating condition as the design condition, and using the design values ​​of the main gas pressure and main gas flow of the system under the power generation condition as the verification condition, the turbine is selected, designed and verified, so as to achieve the purpose of efficient operation of the system under both heating and power generation conditions.

[0081] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

Claims

1. A supercritical carbon dioxide heating and power generation system, characterized in that: It comprises a heating compressor (1), a turbine, an inspiration integrated motor (4) and a power generation compressor (5) which are coaxially arranged in sequence; The turbine is arranged away from the excitation side of the inspiration-integrated motor (4), and the turbine comprises a low-pressure turbine (2) and a high-pressure turbine (3) that are coaxial and arranged back to back; wherein the low-pressure turbine (2) is connected to the heating compressor (1), and the high-pressure turbine (3) is connected to the inspiration-integrated motor (4); The matching design process of the supercritical carbon dioxide heating and power generation system is as follows: The turbine is selected, designed, and calibrated using the design values ​​of the system's main gas pressure and main gas flow rate under heating conditions as design conditions and the design values ​​of the system's main gas pressure and main gas flow rate under power generation conditions as calibration conditions. The process for determining the design values ​​of the system's main gas pressure and main gas flow rate under power generation conditions is as follows: Based on the main gas pressure and main gas flow of the system under heating conditions, the turbine is selected and designed to obtain a design and selection result of geometric parameters of the turbine; Drawing a turbine pressure-flow performance curve based on the turbine geometric parameter design and selection results; Taking the system power generation under power generation conditions as the target parameter and the system main gas pressure and main gas flow rate as floating parameters, draw the system main gas pressure-main gas flow rate relationship curve under power generation conditions; According to the turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under power generation conditions, the design values ​​of the system main gas pressure and main gas flow under power generation conditions are obtained; The process of obtaining the design values ​​of the system's main gas pressure and main gas flow under power generation conditions based on the turbine pressure-flow performance curve and the system's main gas pressure-main gas flow relationship curve under power generation conditions includes: A two-dimensional rectangular coordinate system is constructed with the pressure parameter as the horizontal axis and the flow parameter as the vertical axis to obtain a pre-constructed two-dimensional rectangular coordinate system; The turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under power generation conditions are simultaneously plotted in a pre-constructed two-dimensional rectangular coordinate system, and the coordinates of the intersection of the turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under power generation conditions are solved to obtain the design values ​​of the system main gas pressure and main gas flow under power generation conditions.

2. A supercritical carbon dioxide heating and power generation system according to claim 1, characterized in that: It also includes a first gearbox (6) and a second gearbox (7); the first gearbox (6) is arranged between the heating compressor (1) and the low-pressure turbine (2), and the second gearbox (7) is arranged between the inspiration integrated motor (4) and the power generation compressor (5).

3. The supercritical carbon dioxide heating and power generation system according to claim 1, characterized in that: The heating compressor (1), the low-pressure turbine (2) and the high-pressure turbine (3) are provided with a unified expansion and sliding system; wherein the expansion dead points of the heating compressor (1), the low-pressure turbine (2) and the high-pressure turbine (3) are all provided at the shaft connection between the high-pressure turbine (3) and the inspiration integrated motor (4).

4. A supercritical carbon dioxide heating and power generation system according to claim 3, characterized in that: The heating compressor (1), the low-pressure turbine (2), and the high-pressure turbine (3) all expand toward the free end of the heating compressor (1).

5. The supercritical carbon dioxide heating and power generation system according to claim 1, characterized in that: The rated speeds of the low-pressure turbine (2) and the high-pressure turbine (3) are the same as the rated speed of the inspiration motor (4).

6. The supercritical carbon dioxide heating and power generation system according to claim 1, characterized in that: The power supply terminal of the inspiration integrated motor (4) is connected to the power grid, and a frequency converter (8) and a bypass switch (9) are provided between the inspiration integrated motor (4) and the power grid; wherein the frequency converter (8) and the bypass switch (9) are provided in parallel.

7. The method for operating a supercritical carbon dioxide heating and power generation system according to any one of claims 1 to 6, characterized in that: Including system startup phase and operation phase; During the system startup phase, the inspiration integrated motor (4) is started at a variable speed; during the operation phase, the inspiration integrated motor (4) operates at a rated speed.

8. The method for operating a supercritical carbon dioxide heating and power generation system according to claim 7, characterized in that: The operation phase includes heating conditions and power generation conditions; Under the heating condition, the power generation compressor (5) is disconnected from the inspiration integrated motor (4), and the heating compressor (1) operates normally; In the power generation mode, the heating compressor (1) is disconnected from the low-pressure turbine (2), and the power generation compressor (5) operates normally.

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