Supercritical carbon dioxide heat supply and power generation system and operation method thereof

Abstract

The invention belongs to the technical field of supercritical carbon dioxide cycle power generation, and discloses a supercritical carbon dioxide heat supply and power generation system and an operation method thereof.The supercritical carbon dioxide heat supply and power generation system comprises a heat supply compressor, a turbine, a starting and power generation integrated motor and a power generation compressor which are coaxially arranged in sequence; the turbines are arranged far away from the excitation side of the starting and generating integrated motor, and the turbines comprise a low-pressure turbine and a high-pressure turbine which are coaxial and arranged in a back-to-back mode; wherein the low-pressure turbine is connected with a heating compressor, and the high-pressure turbine is connected with the starting and starting integrated motor; the starting and starting integrated motor, the high-pressure turbine and the low-pressure turbine are coaxially arranged, the heating compressor and the power generation compressor are arranged at the two ends of the system, and the output requirements under the heating and power generation working conditions are met at the same time through one set of host equipment; and efficient operation of the system under a heat supply working condition and a power generation working condition can be ensured without configuring 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 particularly relates to a supercritical carbon dioxide heating and power generation system and an operation method thereof. Background Art

[0002] The supercritical carbon dioxide power generation technology uses supercritical carbon dioxide as a circulating working medium, which has the advantages of high cycle efficiency, compact equipment structure, and small initial capital investment; in a supercritical carbon dioxide power generation system, it is usually required to simultaneously meet the heating conditions in winter and the power generation conditions in summer, that is, a large heat supply is required under the heating conditions, and as high a power generation efficiency as possible is required under the power generation conditions.

[0003] At present, in order to enable the system to simultaneously meet the heating conditions in winter and the power generation conditions in summer, the thermal power under the heating conditions is much greater than the thermal power under the power generation conditions, and the main gas flow rate and main gas pressure of the system under the heating conditions are generally much greater than the main gas flow rate and main gas pressure of the system under the power generation conditions; therefore, existing supercritical carbon dioxide power generation systems usually are equipped with two sets of main engine equipment to simultaneously meet the requirements of the heating conditions in winter and the power generation conditions in summer; however, when a supercritical carbon dioxide power generation system is equipped with two sets of main engine 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] Aiming at 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 of increased difficulty in system integration and coordinated control and increased initial investment costs that generally exist when a supercritical carbon dioxide power generation system is equipped with two sets of main engine equipment.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides a supercritical carbon dioxide heating and power generation system, including a heating compressor, a turbine, an excitation integrated motor, and a power generation compressor arranged coaxially in sequence. The turbine is arranged on the side of the excitation side of the excitation integrated motor away from it, and the turbine includes a low-pressure turbine and a high-pressure turbine arranged coaxially and back-to-back; wherein, the low-pressure turbine is connected to the heating compressor, and the high-pressure turbine is connected to the excitation integrated motor.

[0006] Further, the matching design process of the supercritical carbon dioxide heating and power generation system is as follows: Taking the design values of the main steam pressure and main steam flow rate of the system under the heating condition as the design condition, and taking the design values of the main steam pressure and main steam flow rate of the system under the power generation condition as the verification condition, the turbine is selected and designed and verified; wherein, the determination process of the design values of the main steam pressure and main steam flow rate of the system under the power generation condition is as follows: Based on the main steam pressure and main steam flow rate of the system under the heating condition, the turbine is selected and designed to obtain the design selection result of the geometric parameters of the turbine; Using the design selection result of the geometric parameters of the turbine, the turbine pressure-flow performance curve is drawn; Taking the system power generation power under the power generation condition as the target parameter and the main steam pressure and main steam flow rate of the system as the floating parameters, the main steam pressure-main steam flow rate relationship curve of the system under the power generation condition is drawn; According to the turbine pressure-flow performance curve and the main steam pressure-main steam flow rate relationship curve of the system under the power generation condition, the design values of the main steam pressure and main steam flow rate of the system under the power generation condition are obtained.

[0007] Furthermore, the process of obtaining the design values of the main steam pressure and main steam flow rate of the system under the power generation condition according to the turbine pressure-flow performance curve and the main steam pressure-main steam flow rate relationship curve of the system under the power generation condition includes: Taking the pressure parameter as the horizontal axis and the flow parameter as the vertical axis to construct a two-dimensional rectangular coordinate system to obtain the pre-constructed two-dimensional rectangular coordinate system; The turbine pressure-flow performance curve and the main steam pressure-main steam flow rate relationship curve of the system under the power generation condition are simultaneously drawn in the pre-constructed two-dimensional rectangular coordinate system, and the intersection coordinates of the turbine pressure-flow performance curve and the main steam pressure-main steam flow rate relationship curve of the system under the power generation condition are solved to obtain the design values of the main steam pressure and main steam flow rate of the system under the power generation condition.

[0008] 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 starting and generating motor and the power generation compressor.

[0009] Furthermore, the heating compressor, the low-pressure turbine and the high-pressure turbine are provided with a unified expansion and sliding elimination system; wherein, the expansion dead points of the heating compressor, the low-pressure turbine and the high-pressure turbine are all arranged at the shafting connection of the high-pressure turbine and the integrated starting and generating motor.

[0010] Furthermore, the heating compressor, the low-pressure turbine and the high-pressure turbine expand uniformly towards the free end of the heating compressor.

[0011] Further, the rated speeds of the low-pressure turbine and the high-pressure turbine are the same as the rated speed of the integrated motor-generator.

[0012] Further, the power supply terminal of the integrated motor-generator is connected to the power grid, and a frequency converter and a bypass switch are also arranged between the integrated motor-generator and the power grid; wherein, the frequency converter and the bypass switch are arranged in parallel.

[0013] The present invention also provides an operation method for a supercritical carbon dioxide heating and power generation system, including a system startup stage and an operation stage; During the system startup stage, the integrated motor-generator starts up at a variable speed; during the operation stage, the integrated motor-generator operates at the rated speed.

[0014] Further, the operation stage includes a heating condition and a power generation condition; Under the heating condition, the power generation compressor is disconnected from the integrated motor-generator, and the heating compressor operates normally; Under the power generation condition, the heating compressor is disconnected from the low-pressure turbine, and the power generation compressor operates normally.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The supercritical carbon dioxide heating and power generation system provided by the present invention arranges the integrated motor-generator, 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 main equipment to simultaneously meet the output requirements under the heating and power generation conditions, and it is not necessary to configure two sets of main equipment at the same time to ensure the efficient operation of the system under the heating and power generation conditions; the equipment in the system is arranged coaxially in sequence, reducing the number of equipment and the connecting parts and pipelines between the equipment, making the system structure more compact, greatly reducing the integration and coordinated control difficulty of the system, and at the same time being able to effectively reduce the initial investment and effectively improve the engineering economy of the unit; among them, arranging the low-pressure turbine and the high-pressure turbine coaxially and back-to-back can automatically adjust the output power according to the load demand, ensure the stable working state of the compressor and the integrated motor-generator, realize load balancing and power regulation, and further improve the operation efficiency of the system; secondly, the application of the integrated motor-generator enables the system to flexibly switch between the power generation and motor modes, improving the flexibility and adaptability of the system.

[0016] Further, taking the design values of the main gas pressure and the main gas flow rate of the system under the heating condition as the design condition, and taking the design values of the main gas pressure and the main gas flow rate of the system under the power generation condition as the verification condition, to carry out load matching design verification for the turbine under the heating and power generation dual conditions, so that it can efficiently meet the high-efficiency, safe and stable operation of the heating and power generation dual conditions at the same time. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Structural schematic diagram of the supercritical carbon dioxide heating and power generation system provided for the embodiment; Figure 2 Shafting layout diagram under heating condition in the embodiment; Figure 3 Shafting layout diagram under power generation condition in the embodiment; Figure 4 Electrical principle schematic diagram of the supercritical carbon dioxide heating and power generation system described in the embodiment; Figure 5 Schematic diagram of the matching design principle of the supercritical carbon dioxide heating and power generation system in the embodiment.

[0019] Among them, 1 is the heating compressor, 2 is the low-pressure turbine, 3 is the high-pressure turbine, 4 is the excitation-integrated motor, 5 is the power generation compressor, 6 is the first gearbox, 7 is the second gearbox, 8 is the frequency converter, 9 is the bypass switch, and 10 is the vacuum circuit breaker. Detailed implementation manners

[0020] In order to make the technical problems, technical solutions and beneficial effects solved by the present application more clearly understood, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application; obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0021] The present invention provides a supercritical carbon dioxide heating and power generation system, including a heating compressor 1, a turbine, an excitation-integrated motor 4 and a power generation compressor 5 arranged coaxially in sequence; the turbine is arranged on the excitation side away from the excitation-integrated motor 4, and the turbine includes a low-pressure turbine 2 and a high-pressure turbine 3 arranged coaxially and back to back; among them, the low-pressure turbine 2 is connected to the heating compressor 1, and the high-pressure turbine 3 is connected to the excitation-integrated motor 4.

[0022] The matching design process of the supercritical carbon dioxide heating and power generation system is as follows: Taking the design values of the main steam pressure and main steam flow rate of the system under the heating condition as the design condition, and taking the design values of the main steam pressure and main steam flow rate of the system under the power generation condition as the verification condition, the turbine is selected and designed and verified; wherein, the determination process of the design values of the main steam pressure and main steam flow rate of the system under the power generation condition includes: based on the main steam pressure and main steam flow rate of the system under the heating condition, the turbine is selected and designed to obtain the design selection result of the geometric parameters of the turbine; using the design selection result of the geometric parameters of the turbine, the turbine pressure-flow performance curve is drawn; taking the system power generation power under the power generation condition as the target parameter and the main steam pressure and main steam flow rate of the system as the floating parameters, the system main steam pressure-main steam flow rate curve under the power generation condition is drawn; according to the turbine pressure-flow performance curve and the system main steam pressure-main steam flow rate curve under the power generation condition, the design values of the main steam pressure and main steam flow rate of the system under the power generation condition are obtained.

[0023] In the supercritical carbon dioxide heating power generation system of the present invention, the heating compressor, the turbine, the integrated starting and generating motor, and the power generation compressor are arranged coaxially in sequence. Among them, the turbine adopts a high-pressure turbine and a low-pressure head arranged back-to-back, realizing the compact and efficient design of the system, and meeting the heating and power generation condition requirements of the system without designing two sets of independent main equipment; secondly, the matching design process comprehensively considers the heating and power generation conditions. Through turbine selection design, drawing the pressure-flow curve, and optimizing with the power generation power as the target parameter, the design values of the main steam pressure and main steam flow rate under the power generation condition are determined, and the turbine selection design result is verified with the design values of the main steam pressure and main steam flow rate under the power generation condition as the verification condition, thereby ensuring the efficient and stable operation of the system under different conditions.

[0024] The following uses some specific embodiments to further explain the supercritical carbon dioxide heating power generation system provided by the present invention: Embodiment As shown in the appendix Figure 1 As shown, this embodiment provides a supercritical carbon dioxide heating power generation system, which includes a heating compressor 1, a first gearbox 6, a low-pressure turbine 2, a high-pressure turbine 3, an integrated starting and generating motor 4, a second gearbox 7, and a power generation compressor 5 arranged coaxially in sequence.

[0025] In this embodiment, the heating compressor 1, the first gearbox 6, the low-pressure turbine 2, the high-pressure turbine 3, and the integrated starting and generating machine 4 are connected coaxially in sequence to form a heating condition shafting, as shown in the appendix Figure 2As shown in the figure; 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, a first coupling is used between the first gearbox 6 and the heating compressor 1; 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 away from the integrated motor-generator 4.

[0026] In the shafting of the heat supply working condition, 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 integrated motor-generator 4.

[0027] In this embodiment, the low-pressure turbine 2, the high-pressure turbine 3, the integrated motor-generator 4, the second gearbox 7 and the generator compressor 5 are coaxially connected in sequence to form a shafting for the power generation working condition, as shown in the appendix Figure 3 As shown in the figure; 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 away from the integrated motor-generator 4, one end of the excitation side of the integrated motor-generator 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 generator compressor 5; wherein, a second coupling is used between the second gearbox 7 and the generator compressor 5.

[0028] 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 elimination system to ensure smooth thermal expansion of the cylinder bodies of the low-pressure turbine 2 and the high-pressure turbine 3; 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 shafting connection between the high-pressure turbine 3 and the integrated motor-generator 4; the heating compressor 1, the low-pressure turbine 2 and the high-pressure turbine 3 expand uniformly towards the free end of the heating compressor 1.

[0029] In this embodiment, the integrated motor-generator 4 adopts an integrated motor-generator synchronous excitation generator, and the integrated motor-generator synchronous excitation generator is equipped with a 50% rated power frequency converter; in the system startup stage, the integrated motor-generator 4 acts as a motor and starts the system in a variable-speed startup mode to establish an initial pressure for the system; in the system operation stage, the integrated motor-generator 4 acts as a generator and operates at the rated speed; the power supply end of the integrated motor-generator 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 integrated motor-generator 4 and the power grid, as shown in the appendix Figure 4As shown in the figure; among them, the connection mode of the frequency converter 8, bypass switch 9 and 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 arranged on the side close to the power grid.

[0030] In this embodiment, a hoist or slide rail device is provided at the power generation compressor 5; the hoist or slide rail device is used to move the power generation compressor 5 to facilitate the removal of the rotor of the integrated motor-generator 4 for maintenance; specifically, before removing the rotor of the integrated motor-generator 4 for maintenance, the power generation compressor 5 is integrally moved to a preset position by the hoist or slide rail device to provide sufficient maintenance space; after the maintenance is completed, the power generation compressor 5 is moved back to the installation position of the power generation compressor by the hoist or slide rail device.

[0031] 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-generator 4 and the power generation compressor 5 to increase the speed of the heating compressor 1 and the power generation compressor 5 by using the first gearbox 6 and the second gearbox 7 respectively.

[0032] Matching design process: For the supercritical carbon dioxide heating power generation system described in this embodiment, a matching design process is carried out. The design values of the main gas pressure and main gas flow rate of the system under the heating condition are used as the design conditions, and the design values of the main gas pressure and main gas flow rate of the system under the power generation condition are used as the verification conditions to select and design and verify the turbine. The following takes the selection and design and verification process of the high-pressure turbine as an example, specifically as follows: Step 1: Based on the design values of the main gas pressure and main gas flow rate of the system under the heating condition as the design conditions, select and design the high-pressure turbine to obtain the design selection results of the geometric parameters of the high-pressure turbine; among them, the design selection results of the geometric parameters of the high-pressure turbine include the rotational speed, number of stages, outer diameter of the impeller, number of blades, blade height and inlet and outlet installation angles of the high-pressure turbine.

[0033] Step 2: According to the design selection results of the geometric parameters of the high-pressure turbine, draw the pressure-flow performance curve of the high-pressure turbine; among them, the pressure-flow performance curve of the high-pressure turbine is the off-design performance curve of the high-pressure turbine, that is, the relationship curve between the inlet pressure and inlet flow rate of the high-pressure turbine; it should be noted that under the condition that the system back pressure remains unchanged, the inlet pressure and inlet flow rate of the high-pressure turbine 2 are positively correlated.

[0034] Step 3: Taking the system power generation power under the power generation condition as the target parameter and the main steam pressure and main steam flow rate of the system as floating parameters, draw the relationship curve of the main steam pressure - main steam flow rate of the system under the power generation condition; it should be noted that under the condition of constant system power generation power, the relationship curve of the main steam pressure - main steam flow rate of the system under the power generation condition shows an inverse correlation.

[0035] Step 4: Determine the design values of the main steam pressure and main steam flow rate of the system under the power generation condition according to the high-pressure turbine pressure - flow performance curve and the main steam pressure - main steam flow curve of the system under the power generation condition; the specific process is as follows: Construct a two-dimensional rectangular coordinate system with the pressure parameter as the horizontal axis and the flow parameter as the vertical axis to obtain the pre-constructed two-dimensional rectangular coordinate system; plot the high-pressure turbine pressure - flow performance curve and the main steam pressure - main steam flow curve of the system under the power generation condition in the pre-constructed two-dimensional rectangular coordinate system at the same time, and solve the intersection coordinates of the high-pressure turbine pressure - flow performance curve and the main steam pressure - main steam flow curve of the system under the power generation condition to obtain the design values of the main steam pressure and main steam flow rate of the system under the power generation condition.

[0036] It should be noted that since the change trends of the high-pressure turbine pressure - flow performance curve and the main steam pressure - main steam flow curve of the system under the power generation condition are opposite, there must be a unique and stable intersection point in the same two-dimensional rectangular coordinate system, as shown in the appendix Figure 5 shown; among them, the abscissa of the intersection point is the design value of the main steam pressure of the system under the power generation condition, and the ordinate of the intersection point is the design value of the main steam flow rate of the system under the power generation condition.

[0037] Step 5: Based on the design selection result of the geometric parameters of the high-pressure turbine, obtain the design selection result of the high-pressure turbine; take the design values of the main steam pressure and main steam flow rate of the system under the power generation condition as the verification condition, and verify the design selection result of the high-pressure turbine to verify the performance of the design selection result of the high-pressure turbine under the verification condition; among them, if the performance of the design selection result of the high-pressure turbine under the verification condition is in the high-efficiency performance area, output the design selection result of the high-pressure turbine.

[0038] It should be noted that since the turbine power under the heating condition is greater than that under the power generation condition, in order to save equipment costs and ensure that the turbine can operate efficiently under both the heating condition and the power generation condition, in this embodiment, the flow rate and pressure parameters of the system under the heating condition 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 with unchanged system back pressure can be obtained, that is, the turbine pressure-flow performance curve; 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 rate and the main gas pressure, that is, the main gas pressure-main gas flow rate curve of the system under the power generation condition can be obtained; by coupling and solving the intersection relationship between the turbine pressure-flow performance curve and the main gas pressure-main gas flow rate curve of the system under the power generation condition, the unique and stable main gas flow rate and main gas pressure can be obtained as the design parameters for the power generation condition, and the design parameters for the power generation condition are used as the verification condition to select and verify the turbine.

[0039] It should also be noted that the process of selecting, designing and verifying the low-pressure turbine is basically the same as that of the high-pressure turbine described above, so it will not be elaborated here.

[0040] Working principle and operation method: The supercritical carbon dioxide heating power generation system described in this embodiment, during operation, includes a system startup stage and an operation stage; among them, during the system startup stage, the integrated motor-generator 4 starts with variable speed; during the operation stage, the integrated motor-generator 4 operates at a rated speed; specifically, In the startup stage, the system draws power from the power grid, and the integrated motor-generator 4 is in the motor operation state; the industrial frequency alternating current of the power grid is frequency-converted by the frequency converter 8 and then transmitted to the integrated motor-generator 4, and the integrated motor-generator 4 starts with variable speed and gradually increases its speed; after the main gas temperature and main gas pressure of the system gradually rise to meet the turbine turning conditions, the turbine starts to turn and increase its 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 decreases to zero, the bypass switch 9 closes, the frequency converter 8 shuts down, and the integrated motor-generator 4 switches to the generator operation state and starts to output electric energy to the power grid.

[0041] In the operation stage, the operating conditions of the system include the heating condition and the power generation condition; under the heating condition, the power generation compressor 5 is disconnected from the integrated motor-generator 4, and the heating compressor 1 operates normally; specifically, the second coupling is unfastened, the power generation compressor 5 stops operating, 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 unfastened, the heating compressor 1 stops operating, and the power generation compressor 5 operates; among them, under the heating condition and the power generation condition, the high-pressure turbine and the low-pressure turbine share the same set of equipment.

[0042] Example illustration: Taking a supercritical carbon dioxide heating and power generation system as an example, the present invention is illustrated as follows: Before the matching design, the boundary parameters of the supercritical carbon dioxide heating and power generation system under the heating condition and the power generation condition are shown in Table 1 below.

[0043] Table 1 Boundary parameters of heating condition and power generation condition

[0044] As can be seen from Table 1, before the matching design, there are large deviations in the compressor inlet temperature, compressor power, turbine power, and main gas pressure between the heating condition and the power generation condition; among them, the thermal power of the system under the heating condition is much greater than that of the system under the power generation condition, and the inlet temperature of the compressor under the heating condition is much higher than that under the power generation condition; at the same time, the shaft power of the compressor under the heating condition is nearly 4 times that of the power generation condition; therefore, it is impossible to share the compressor between the heating condition and the power generation condition, and the heating compressor and the power generation compressor must be designed and selected separately; secondly, due to the too large power deviation between the heating compressor and the power generation compressor under the heating condition, it is impossible to set up an independent driving turbine for the compressor, otherwise the power of the driving turbine will deviate too much between the heating condition and the power generation condition and cannot be balanced, so the compressor shafting and the turbine shafting must be coaxially arranged to maintain the matching and balance of the shafting power under the two conditions.

[0045] In this example, the excitation-integrated motor adopts an excitation-integrated synchronous excitation generator, which is equipped with a 50% rated power frequency converter; during the startup stage, the excitation-integrated motor acts as a motor to establish the initial pressure for the unit; during the operation stage, the excitation-integrated motor acts as a generator and operates at a rated speed of 3000 rpm; a high-pressure turbine and a low-pressure turbine are respectively arranged on the excitation side far away from the excitation-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 speeds of the high-pressure turbine and the low-pressure turbine are the same as that of the excitation-integrated motor, both being 3000 rpm.

[0046] Since the output power of the rotating shaft on the excitation side of the excitation-integrated motor is small, the power generation compressor is arranged on the excitation side close to the excitation-integrated motor, and the heating compressor is arranged on the side close to the low-pressure turbine; gearboxes are arranged between the heating compressor and the power generation compressor and the transmission shaft for speed increase; among them, under the heating condition, the coupling on the power generation compressor side is disengaged, and only the heating compressor operates; under the power generation condition, the coupling on the heating compressor side is disengaged, and only the power generation compressor operates; the high-pressure turbine and the low-pressure turbine need to meet the processing requirements of both the heating condition and the power generation condition, but their condition matching design is required; the process of its matching design is as follows: Take the design values of the main steam pressure and main steam flow rate of the system under the heating condition as the design condition, select and design the turbine to obtain the selection result of the geometric parameters of the turbine; after obtaining the selection result of the geometric parameters of the turbine, draw the off-design performance curve of the turbine with the system back pressure unchanged, that is, the turbine pressure-flow performance curve; then, take the power generation power under the power generation condition as the target parameter, and take the main steam pressure and main steam flow rate of the system as floating parameters, and draw the relationship curve of the main steam pressure-main steam flow rate of the system when the power generation power is unchanged, that is, the main steam pressure-main steam flow rate curve of the system under the power generation condition; the intersection point of the turbine pressure-flow performance curve and the main steam pressure-main steam flow rate curve of the system under the power generation condition is the design value of the main steam pressure and main steam flow rate of the system under the power generation condition; since the change trends of the turbine pressure-flow performance curve and the main steam pressure-main steam flow rate curve of the system under the power generation condition are opposite, there must be a stable intersection point between the two; among them, the pressure at the intersection point is 22.5 MPa and the flow rate is 1566 t / h, which can be used as the design values of the main steam pressure and main steam flow rate of the system under the power generation condition; finally, take the design values of the main steam pressure and main steam flow rate of the system under the power generation condition as the check condition, and check the turbine selected based on the design condition.

[0047] Through the above design and check processes, the design parameters of the system under the heating condition and the power generation condition can be obtained, as shown in Table 2 below.

[0048] Table 2 Comparison of Design Parameters under Heating Condition and Power Generation Condition

[0049] As can be seen from Table 2 above, through the matching design and check, the high-pressure turbine and the low-pressure turbine can simultaneously meet the output requirements under the heating condition and the power generation condition; at the same time, the inlet volume flow rate deviations of the high-pressure turbine and the low-pressure turbine under the power generation condition are only -1.7% and -7.3% respectively, and the volume flow rate deviation is extremely small; therefore, the high-pressure turbine and the low-pressure turbine can maintain high efficiency under the power generation condition.

[0050] For the supercritical carbon dioxide heating power generation system described in the present invention, in the shafting arrangement, a scheme of coaxial arrangement of the inspiration-integrated motor with the high-pressure turbine and the low-pressure turbine is adopted, and the heating compressor and the power generation compressor are arranged at both ends of the system to meet the output requirements of the heating and power generation conditions respectively; secondly, by respectively obtaining the flow-pressure curve of the off-design turbine under the heating condition and the flow-pressure curve of the system under the power generation condition, the intersection flow rate and pressure of the two curves are obtained as the design values of the main steam pressure-main steam flow rate curve of the system under the power generation condition; based on the design values of the main steam pressure and main steam flow rate of the system under the heating condition as the design condition, and taking the design values of the main steam pressure and main steam flow rate of the system under the power generation condition as the check condition, select and design and check the turbine to achieve the purpose of efficient operation of the system under the heating condition and the power generation condition at the same time.

[0051] The above embodiments are only one of the implementation manners capable of implementing the technical solution of the present invention. The scope of protection required by the present invention is not limited only by this embodiment, but also includes any changes, substitutions and other implementation manners that are easily conceivable by any person skilled in the art 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 integrated inspiration motor (4), and comprises a low-pressure turbine (2) and a high-pressure turbine (3) which are coaxially 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).

2. A supercritical carbon dioxide heating and power generation system according to claim 1, characterized in that: The matching design process of the supercritical carbon dioxide heating and power generation system is as follows: The design values ​​of the main gas pressure and the main gas flow rate of the system under the heating condition are taken as the design condition, and the design values ​​of the main gas pressure and the main gas flow rate of the system under the power generation condition are taken as the verification condition, and the turbine is selected, designed and verified; wherein, the process of determining the design values ​​of the main gas pressure and the main gas flow rate of the system under the power generation condition 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 the geometric parameter design and selection results of the turbine; Based on the geometric parameter design and selection results of the turbine, a turbine pressure-flow performance curve is drawn; 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.

3. A supercritical carbon dioxide heating and power generation system according to claim 2, characterized in that: The process of obtaining the design values ​​of the main gas pressure and main gas flow of the system under the power generation condition according to the turbine pressure-flow performance curve and the system main gas pressure-main gas flow relationship curve under the power generation condition includes: A two-dimensional rectangular coordinate system is constructed using 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.

4. 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 heating integrated motor (4) and the power generation compressor (5).

5. 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 elimination system; wherein the expansion dead points of the heating compressor (1), the low-pressure turbine (2) and the high-pressure turbine (3) are all arranged at the shaft connection between the high-pressure turbine (3) and the inspiration integrated motor (4).

6. A supercritical carbon dioxide heating and power generation system according to claim 5, 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).

7. A 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 integrated inspiration motor (4).

8. 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 also arranged between the inspiration integrated motor (4) and the power grid; wherein the frequency converter (8) and the bypass switch (9) are arranged in parallel.

9. The method for operating a supercritical carbon dioxide heating and power generation system according to any one of claims 1 to 8, characterized in that: Includes 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.

10. The method for operating a supercritical carbon dioxide heating and power generation system according to claim 9, 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 all-in-one inspiration machine (4), and the heating compressor (1) operates normally; In the power generation condition, the heating compressor (1) is disconnected from the low-pressure turbine (2), and the power generation compressor (5) operates normally.

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