Turbine of supercritical carbon dioxide outer shell differential expansion decoupling structure and using method

Abstract

The invention discloses a supercritical carbon dioxide outer shell differential expansion decoupling structure turbine and a using method. The performance of rapid starting and rapid adjusting of the turbine is achieved. Comprising an installation shell and an outer volute, a main shaft is arranged in the installation shell, a dry gas seal is arranged between the installation shell and the main shaft, the end of the main shaft is sequentially connected with a transmission shaft and a turbine disc, a cooling shell and a supporting shell are arranged between the installation shell and the main shaft, and a heat insulation layer is installed on the non-runner face of the supporting shell. A cooling air inlet and a cooling air outlet are formed in the mounting shell, a cooling channel is formed in the cooling shell and communicated with the cooling air inlet and the cooling air outlet, an air inlet flow guide shell is mounted in the supporting shell, the nozzle ring, the flow channel side of the supporting shell and the air inlet flow guide shell define an air inlet flow channel, and the air inlet flow channel is communicated with a turbine air inlet. And the high-temperature and high-pressure carbon dioxide working medium radially entering the turbine air inlet flows axially at the tail end of the air inlet flow channel.

Description

Technical Field

[0001] The present invention relates to the technical field of supercritical carbon dioxide cycle power generation, and in particular to a supercritical carbon dioxide outer casing differential expansion decoupling structure turbine and a usage method thereof. Background Art

[0002] The differential expansion of the turbine casing refers to the relative expansion amount of the turbine casing relative to the rotor. In order to control the differential expansion of the casing within the allowable value, the cold start process time of traditional generator sets is very long. With the development of power generation technology, supercritical carbon dioxide, as an excellent working medium replacing steam, is often used in small generator sets that require rapid power generation due to its higher cycle efficiency and more compact equipment layout. Such a power generation system needs to achieve rapid start-up and rapid adjustment of the power generation power. Therefore, the turbine needs to be able to meet the working conditions of rapid temperature change of the working medium. In the traditional turbine structure, too rapid temperature change of the working medium will lead to excessive differential expansion, resulting in serious accidents such as rotor rubbing and damage to the unit. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a supercritical carbon dioxide outer casing differential expansion decoupling structure turbine and a usage method thereof, so as to achieve the performance of rapid start-up and rapid adjustment of the turbine.

[0004] The purpose of the present invention is achieved as follows: A supercritical carbon dioxide outer casing differential expansion decoupling structure turbine includes an installation casing and an outer volute. A main shaft is arranged in the installation casing, and a dry gas seal is provided between the installation casing and the main shaft. The outer volute is provided with a turbine air inlet, an intake high-pressure chamber, an exhaust passage, and a turbine exhaust port along the radial direction. The end of the main shaft is sequentially connected with a transmission shaft and a turbine disk. The main shaft is made of a material that is not resistant to high temperature, and the transmission shaft is made of a high-temperature resistant alloy material. The transmission shaft is used to withstand high temperature and transmit torque. Finally, the three parts of the main shaft, the transmission shaft, and the turbine disk are locked and fixed by a pull rod and a locking nut. A cooling casing and a support casing are sequentially arranged between the installation casing and the main shaft. The cooling casing and the support casing are both fixed on the installation casing. An insulating layer is installed on the non-flow passage surface of the support casing. The installation casing is provided with a cooling gas inlet and a cooling gas exhaust port. The cooling casing is provided with a cooling channel communicating with the cooling gas inlet and the cooling gas exhaust port. Low-temperature and high-pressure carbon dioxide gas is introduced from the cooling gas inlet into the cooling casing, and after cooling the installation casing and the cooling casing, it is discharged from the cooling gas exhaust port. The cooling casing and the insulating layer prevent the support casing from directly conducting heat to the installation casing to protect the components in contact with the installation casing. Inside the support housing, an intake air guide housing and a nozzle ring are installed in sequence from outside to inside. The nozzle ring is located on the intake side of the turbine disk. The flow channel side of the support housing and the intake air guide housing enclose an intake air flow channel, which is connected to the turbine intake port. The high-temperature and high-pressure carbon dioxide working medium that radially enters the turbine intake port forms an axial flow at the end of the intake air flow channel, and then flows out through the nozzle ring, pushing the turbine disk blades, thereby driving the main shaft to do work, and then exhausting from the turbine exhaust port.

[0005] Preferably, the installation housing is installed on the gearbox / high-speed generator, and the main shaft is the shaft extension section of the input shaft of the gearbox / the main shaft of the high-speed generator.

[0006] Preferably, a disk labyrinth seal is provided between the outer circumference of the turbine disk and the intake air guide housing.

[0007] Preferably, an exhaust air guide housing is installed on the support housing. The exhaust air guide housing is located on the exhaust side of the turbine disk. The exhaust air guide housing is used to guide the exhaust of the turbine disk into the exhaust air flow channel. A thrust balance cavity and a balance air flow channel are provided in the exhaust air guide housing. The thrust balance cavity is connected to the intake high-pressure chamber through the balance air flow channel. The balance air flow channel introduces the high-temperature and high-pressure carbon dioxide working medium from the intake high-pressure chamber, thereby balancing the axial force on the turbine disk.

[0008] Preferably, an exhaust air guide housing labyrinth seal is installed on the exhaust air guide housing through an exhaust air guide housing labyrinth seal pressing seat. The exhaust air guide housing labyrinth seal is used to reduce the leakage of the working medium in the thrust balance cavity.

[0009] Preferably, the main shaft and the transmission shaft cooperate to transmit torque through a triangular prism-shaped connection surface, and the transmission shaft and the turbine disk transmit torque through an end face tooth structure.

[0010] Preferably, a transmission shaft seal one and a transmission shaft seal two are installed on the support housing corresponding to both ends of the transmission shaft.

[0011] A method for using a turbine with a supercritical carbon dioxide outer casing differential expansion decoupling structure First, the high-temperature and high-pressure supercritical carbon dioxide working medium enters the intake high-pressure chamber from the turbine intake port, then reaches the nozzle ring through the intake air flow channel, and then is ejected from the nozzle ring to drive the turbine disk blades to drive the main shaft to do work. Finally, it is exhausted from the turbine exhaust port through the exhaust air flow channel to complete the work process; During the work process, since all components adjacent to the turbine disk are not installed on the outer casing, all thermal expansions of the outer casing will not affect the dynamic and static clearances of the turbine, realizing the decoupling of the differential expansion of the turbine outer casing.

[0012] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects: All components adjacent to the turbine disk of the present invention are not installed on the outer volute. Therefore, all thermal expansions of the outer volute will not affect the static and dynamic clearances of the turbine, fully achieving the decoupling of the differential expansion of the turbine housing, enabling the carbon dioxide turbine to achieve the performance of rapid startup and rapid adjustment. Description of the Drawings

[0013] Figure 1 It is a schematic structural diagram of a supercritical carbon dioxide turbine; Figure 2 It is a schematic diagram of the flow channel of a supercritical carbon dioxide turbine; Figure 3 It is a schematic diagram of the connection structure between the main shaft, the transmission shaft, and the turbine disk.

[0014] Reference Numerals in the Drawings In the drawings, 1 is the mounting housing, 2 is the dry gas seal, 3 is the heat insulation layer, 4 is the support housing, 5 is the cooling housing, 6 is the intake guide housing, 7 is the exhaust guide housing, 8 is the outer volute, 9 is the exhaust guide housing serrated seal compression seat, 10 is the exhaust guide housing serrated seal, 11 is the lock nut, 12 is the tie rod, 13 is the disk serrated seal, 14 is the turbine disk, 15 is the nozzle ring, 16 is the transmission shaft seal II, 17 is the transmission shaft, 18 is the transmission shaft seal I, 19 is the main shaft, a1 is the turbine intake port, a2 is the intake high-pressure chamber, a3 is the intake flow channel, a4 is the exhaust flow channel, a5 is the turbine exhaust port, b1 is the cooling air inlet, b2 is the cooling air exhaust port, c1 is the balance air flow channel. Detailed Description of the Invention

[0015] A supercritical carbon dioxide turbine with a differential expansion decoupling structure of the housing includes a mounting housing 1, a dry gas seal 2, a heat insulation layer 3, a support housing 4, a cooling housing 5, an intake guide housing 6, an exhaust guide housing 7, an outer volute 8, an exhaust guide housing serrated seal compression seat 9, an exhaust guide housing serrated seal 10, a lock nut 11, a tie rod 12, a disk serrated seal 13, a turbine disk 14, a nozzle ring 15, a transmission shaft seal II 16, a transmission shaft 17, a transmission shaft seal I 18, and a main shaft 19.

[0016] Among them, the mounting housing 1 can be installed on the gearbox or on the housing of the high-speed generator, and the main shaft 19 is the input shaft of the gearbox or the main shaft extension section of the high-speed generator.

[0017] A dry gas seal 2 is installed on the mounting housing 1 between the mounting housing 1 and the turbine body.

[0018] The support housing 4 and the cooling housing 5 are installed on the mounting housing 1. An insulating layer 3 is installed on the non-flow channel surface of the support housing 4 to isolate the high temperature of the turbine body from being transferred to the low temperature section. In addition, low-temperature and high-pressure carbon dioxide gas is introduced from the cooling gas inlet b1 into the cooling housing 5, and after cooling the mounting housing 1, it is discharged from the cooling gas exhaust port b2 to ensure that the mounting housing 1 is always maintained below the safe temperature and prevent damage to components that are not resistant to high temperatures, such as the dry gas seal 2.

[0019] Since the main shaft 19 usually selects materials that are not resistant to high temperatures, a transmission shaft 17 is provided between the main shaft 19 and the turbine disk 14. The transmission shaft 17 is made of a superalloy material and is used to withstand high temperatures and transmit torque. Torque is transmitted between the main shaft 19 and the turbine disk 14 through the transmission shaft 17. The main shaft 19 and the transmission shaft 17 are connected by a torque transmission structure with a triangular prism-shaped surface, and the transmission shaft 17 and the turbine disk 114 transmit torque through an end face tooth structure. Finally, the three parts of the main shaft 19, the transmission shaft 17, and the turbine disk 14 are locked and fixed by a tie rod 12 and a locking nut 11.

[0020] A transmission shaft seal one 18 and a transmission shaft seal two 16 are installed on the support housing 4 to reduce the sealing gas entering the main flow channel from the dry gas seal 2.

[0021] The intake air guide housing 6 is installed on the support housing 4 and together with the flow channel side of the support housing 4 forms an intake air flow channel a3, allowing the high-temperature and high-pressure carbon dioxide working medium in the main flow channel to change from radial intake to axial flow, and then flowing out through the nozzle ring 15 installed on the support housing to push the blades of the turbine disk 14, thereby driving the main shaft 19 to do work.

[0022] A disk labyrinth seal 13 is provided at the outer circumference of the turbine disk 14 to reduce the leakage of the working medium and increase the turbine efficiency.

[0023] The exhaust gas guide housing 7 and the intake air guide housing 6 are installed on the support housing together. The exhaust gas guide housing 7 has two functions. One is to play the role of exhaust gas guiding, and the other is to form a thrust balance chamber d1 on the exhaust side of the turbine disk 14. High-pressure air is introduced from the intake high-pressure chamber a2 through the balance air flow channel c1 opened on the support ribs of the exhaust gas guide housing 7 to balance the axial force on the turbine disk 14.

[0024] The exhaust gas guide housing labyrinth seal 10 is installed on the exhaust gas guide housing by the exhaust gas guide housing labyrinth seal pressing seat 9 to reduce the leakage of the high-pressure working medium in the balance chamber d1.

[0025] Finally, the outer volute 8 is installed on the mounting housing 1 with high-temperature bolts and nuts.

[0026] Usage method: First, the high-temperature, high-pressure, supercritical carbon dioxide working fluid enters the intake high-pressure chamber a2 through the external turbine intake port a1, then reaches the nozzle ring 15 through the intake flow passage a3, and is then ejected from the nozzle ring 15 to drive the blades of the turbine disk 14 to drive the main shaft 19 to do work. Finally, it is discharged from the turbine exhaust port a5 through the exhaust flow passage a4 to complete the work process.

[0027] During this process, since all the components adjacent to the turbine disk 14 are not installed on the outer volute 8, all the thermal expansions of the outer volute 8 will not affect the static and dynamic clearances of the turbine, and the decoupling of the differential expansion of the outer casing of the turbine is completely realized, enabling the carbon dioxide turbine to achieve the performance of rapid startup and rapid adjustment.

[0028] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A supercritical carbon dioxide outer shell expansion differential decoupling structure turbine, comprising a mounting shell and an outer volute, wherein a main shaft is arranged in the mounting shell, a dry gas seal is arranged between the mounting shell and the main shaft, and a turbine air inlet, an air inlet high pressure chamber, an exhaust flow channel, and a turbine exhaust port are arranged radially on the outer volute, characterized in that: The ends of the main shaft are connected with the transmission shaft and the turbine disk in sequence. The main shaft is made of a material that is not resistant to high temperatures, while the transmission shaft is made of a high-temperature resistant alloy material. The transmission shaft is used to withstand high temperatures and transmit torque. The main shaft, the transmission shaft, and the turbine disk are connected in series by a tie rod. One end of the tie rod is matched with the main shaft thread, and the other end is locked and fixed by a locking nut. A cooling shell and a supporting shell are sequentially arranged between the mounting shell and the main shaft. The cooling shell and the supporting shell are both fixed on the mounting shell. A heat insulation layer is installed on the non-flow channel surface of the supporting shell. A cooling air inlet and a cooling air exhaust port are arranged on the mounting shell. A cooling channel is arranged on the cooling shell and is connected with the cooling air inlet and the cooling air exhaust port. Low-temperature and high-pressure carbon dioxide gas is introduced into the cooling shell from the cooling air inlet, and is discharged from the cooling air exhaust port after cooling the mounting shell and the cooling shell. The cooling shell and the heat insulation layer prevent the supporting shell from directly conducting heat to the mounting shell, so as to protect the components in contact with the mounting shell. An intake guide housing and a nozzle ring are installed inside the support housing from the outside to the inside. The nozzle ring is located on the intake side of the turbine disk. The flow channel side of the support housing and the intake guide housing form an intake flow channel. The intake flow channel is connected to the turbine inlet. The high-temperature and high-pressure carbon dioxide working fluid that radially enters the turbine inlet forms an axial flow at the end of the intake flow channel, and then flows out through the nozzle ring to push the turbine disk blades, thereby driving the main shaft to do work, and then discharged from the turbine exhaust port.

2. A supercritical carbon dioxide outer shell expansion differential decoupling structure turbine according to claim 1, characterized in that: The mounting housing is mounted on the gearbox / high-speed generator, and the main shaft is the shaft extension section of the input shaft of the gearbox / high-speed generator main shaft.

3. The supercritical carbon dioxide outer shell expansion differential decoupling structure turbine according to claim 1, characterized in that: A wheel disc sparse tooth seal is arranged between the outer circle of the turbine disc and the air intake guide housing.

4. The supercritical carbon dioxide outer shell expansion differential decoupling structure turbine according to claim 1, characterized in that: An exhaust guide shell is installed on the support shell. The exhaust guide shell is located on the exhaust side of the turbine disk. The exhaust guide shell is used to guide the exhaust of the turbine disk into the exhaust flow channel. A thrust balance chamber and a balance flow channel are provided in the exhaust guide shell. The thrust balance chamber is connected with the intake high-pressure chamber through the balance flow channel. The balance flow channel introduces high-temperature and high-pressure carbon dioxide working medium from the intake high-pressure chamber, thereby balancing the axial force on the turbine disk.

5. A supercritical carbon dioxide outer shell expansion differential decoupling structure turbine according to claim 4, characterized in that: An exhaust guide housing sparse-tooth seal is installed on the exhaust guide housing through an exhaust guide housing sparse-tooth seal compression seat, and the exhaust guide housing sparse-tooth seal is used to reduce the leakage of the working medium in the thrust balance cavity.

6. The supercritical carbon dioxide outer shell expansion differential decoupling structure turbine according to claim 1, characterized in that: The main shaft and the transmission shaft transmit torque through the triangular prism-shaped connecting surface, and the transmission shaft and the turbine disc transmit torque through the end face tooth structure.

7. The supercritical carbon dioxide outer shell expansion differential decoupling structure turbine according to claim 1, characterized in that: A transmission shaft seal 1 and a transmission shaft seal 2 are installed on the supporting shell at two ends corresponding to the transmission shaft.

8. A method for using the supercritical carbon dioxide shell expansion differential decoupling structure turbine according to claim 1, characterized in that: First, the high-temperature and high-pressure supercritical carbon dioxide working fluid enters the intake high-pressure chamber from the turbine intake port, then passes through the intake flow channel to reach the nozzle ring, and then is ejected from the nozzle ring to push the turbine disk blades to drive the main shaft to work, and finally is discharged from the turbine exhaust port through the exhaust flow channel to complete the work process; During the power generation process, since all components adjacent to the turbine disc are not installed on the outer volute, all thermal expansion of the outer volute will not affect the dynamic and static clearance of the turbine, thereby achieving decoupling of the expansion difference between the turbine and the outer casing.

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