Axial steam exhaust device of large photo-thermal steam turbine

Abstract

The invention discloses an axial steam exhaust device of a large photo-thermal steam turbine. The axial steam exhaust device comprises a steam exhaust device shell, a front expansion joint, a rear expansion joint, four sets of evenly-distributed pull rods, a hot well and a support system. A flange at the front end of the shell is connected with a turbine low-pressure exhaust hood, an air cooling island pipeline is welded to the rear end of the shell, expansion joints at the two ends are hinged through pull rods to form a self-balancing stress chain, air cooling island vacuum thrust is directly conducted to a turbine, and stress of fixing points of the shell is eliminated. The support system comprises an exhaust hood boss-groove dead point, a shell fixing support and a front end guide sliding support, and it is guaranteed that the whole system is free of stress expansion. The hot well is hung below the shell and internally provided with a membrane type nozzle, so that condensed water of the air cooling island is atomized and then makes contact with dead steam for heat regeneration and oxygen removal. The three-stage temperature and pressure reduction device outside the shell adapts to the start-stop working condition of the unit. According to the device, through mechanical self-balance, thermal expansion dredging and efficient heat and mass transfer, the problems of vacuum thrust harm, expansion control and drainage efficiency of an axial steam exhaust unit are solved, and the safety of the unit and the system circulation efficiency are improved.

Description

Technical Field

[0001] The present invention relates to an exhaust device, and in particular to a device for receiving axial exhaust of a direct air-cooled solar thermal steam turbine in the field of large-scale solar thermal power generation. Background Art

[0002] In the field of large-scale solar thermal power generation, the unit capacity is mostly in the range of 100 - 200 MW, and the diameter of the exhaust steam pipeline of the steam turbine reaches 4.5 - 6 m. The axial exhaust form is widely used because it reduces the steam flow friction loss and the exhaust resistance, but there are the following technical problems:

[0003] Vacuum thrust problem: When the steam turbine operates, it is subject to an axial thrust in the opposite direction of the exhaust direction (the magnitude is the product of the cross-sectional area S of the exhaust port and the internal and external pressure difference △P). If not controlled, it will pose a hazard to the safety of the unit.

[0004] Thermal expansion guidance: The steam turbine generates horizontal and vertical thermal displacements in the axial and radial directions. It is necessary to design a reasonable dead point and structure to absorb the expansion amount.

[0005] Drainage and deaeration efficiency: The traditional drainage method with a low-level water tank equipped with a drainage pump results in a large condensate subcooling degree, high oxygen content, and insufficient regenerative heating, reducing the system cycle efficiency.

[0006] The prior art has not effectively solved the above problems. There is an urgent need for an integrated device to achieve self-balancing of vacuum force, thermal expansion compensation, and efficient drainage and deaeration. Summary of the Invention

[0007] The present invention aims to overcome the above-mentioned disadvantages of the prior art and provides an axial exhaust device for a large-scale solar thermal steam turbine.

[0008] The technical solution adopted by the present invention is as follows:

[0009] An axial exhaust device for a large-scale solar thermal steam turbine includes a low-pressure exhaust cylinder of the steam turbine, an exhaust device housing, an air-cooled island exhaust pipeline, a hot well, and a support system. Front-end expansion joints and rear-end expansion joints are respectively arranged at both ends of the exhaust device housing, and the front and rear expansion joints are connected by multiple tie rods;

[0010] The axial centerlines of the exhaust device housing and the low-pressure exhaust cylinder of the steam turbine are collinear. The front end is connected to the exhaust cylinder by a flange, and the rear end is welded to the air-cooled island exhaust pipeline through a collar; the hot well is arranged below the housing;

[0011] The support system includes an exhaust cylinder dead point, a housing fixed dead point, and a front-end guiding sliding support. The exhaust cylinder dead point is arranged on the low-pressure exhaust cylinder of the steam turbine, the housing fixed dead point is fixedly arranged at one end of the exhaust device housing close to the air-cooled island exhaust pipeline, and the sliding support is slidably arranged at one end of the exhaust device housing close to the low-pressure exhaust cylinder of the steam turbine.

[0012] Furthermore, there are four groups of tie rods, which are evenly distributed around the shell at intervals of 90°. Both ends of each group of tie rods are hinged to the expansion joint through cylindrical pins.

[0013] Furthermore, a limit clamp is provided in the middle of the tie rod. One end of the clamp is welded to the shell to limit the axial displacement of the tie rod within a reasonable range.

[0014] Furthermore, the front expansion joint includes two groups, which are used to compensate for axial displacement and absorb radial vibration; the rear expansion joint is a single-layer bellows.

[0015] Furthermore, the dead point of the exhaust cylinder is a boss-groove fit structure. The boss is fixed to the bottom of the exhaust cylinder, and the groove is embedded in the foundation platform.

[0016] Furthermore, the sliding support includes an axial chute fixed to the foundation and a slider welded to the shell. When the shell expands thermally, the slider can slide axially in the axial chute along the axis of the shell and limit the radial displacement of the shell.

[0017] Furthermore, it includes a hot well skirt support and a spring support. The upper end of the spring support is connected to the skirt support, and the lower end is connected to a hot well. The hot well skirt support is connected to the shell, and there are at least two spring supports.

[0018] Furthermore, the hot well is provided with a hot well limit device along the outer facade of the steam turbine axis to ensure smooth thermal expansion of the exhaust steam device.

[0019] Furthermore, the hot well is provided with a return water nozzle assembly.

[0020] Furthermore, a three-stage desuperheating and pressure reducing device is provided on the outside of the shell.

[0021] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0022] Vacuum force self-balancing: Four groups of evenly distributed tie rods link the front and rear expansion joints, directly conducting the vacuum thrust of the air-cooled island to the exhaust cylinder of the steam turbine, eliminating the force on the fixed point of the shell, and avoiding the complex structure and burnout risk of the traditional thrust bearing.

[0023] Omnidirectional thermal expansion guidance: The front double expansion joints compensate for axial displacement and absorb radial vibration. The sliding support allows the shell to slide axially freely, and the boss-groove dead point limits the radial displacement, realizing stress-free thermal expansion of the entire system of the steam turbine - exhaust steam device - air-cooled island.

[0024] Efficient hydrophobic deaeration: The hot well is internally provided with a spiral nozzle, which atomizes the condensate and makes it fully contact with the exhaust steam, strengthening the effect of regenerative deaeration; the low-level layout shortens the hydrophobic path, reduces the degree of subcooling, and improves the quality of the condensate.

[0025] Vibration suppression: The stiffness matching of the expansion joint and the damping design of the sliding support attenuate the structural vibration caused by the exhaust steam pulsation, ensuring long-term operation stability.

[0026] Modular maintenance: The pull rod pin is hinged and the detachable clamp is designed to support the individual replacement of the expansion joint, avoiding overall disassembly and assembly; the spring support has elastic buffering to reduce the stress concentration of the hot well load-bearing.

[0027] Adaptation to special working conditions: The three-stage desuperheating device responds quickly to emergency exhaust steam, reduces the thermal shock of extreme working conditions on the equipment, and extends the service life of the core components. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the axial exhaust device of the present invention;

[0029] Figure 2 It is a schematic structural diagram of the sliding support of the present invention.

[0030] Figure 3 It is a schematic diagram of the support layout of the axial exhaust device.

[0031] Markings in the figure:

[0032] 1 - Front-end expansion joint, 2 - Pull rod, 3 - Exhaust device housing, 4 - Clamp, 5 - Rear-end expansion joint, 6 - Cylindrical pin, 7 - Fixed dead point, 8 - Hot well skirt, 9 - Spring support, 10 - Limiting device, 11 - Return water nozzle assembly, 12 - Hot well, 13 - Three-stage desuperheating and decompression device, 14 - Sliding support, 15 - Exhaust cylinder, 16 - Exhaust cylinder dead point, 17 - Slide block.

[0033] Specific Examples

[0034] The present invention will be described in detail below with reference to the drawings.

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Embodiment 1

[0037] In this embodiment, as Figure 1 shown, a large-scale solar thermal steam turbine axial exhaust device includes a low-pressure exhaust cylinder of the steam turbine, an exhaust device housing, an air-cooled island exhaust pipe, a hot well and a support system. Front-end and rear-end expansion joints are respectively arranged at both ends of the exhaust device housing, and the front-end and rear-end expansion joints are connected by multiple pull rods;

[0038] The axial center line of the exhaust device housing is collinear with that of the low-pressure exhaust cylinder of the steam turbine. The front end is connected to the exhaust cylinder by a flange, and the rear end is welded to the air-cooled island exhaust pipe through a collar; the hot well is arranged below the housing;

[0039] The support system includes the dead center of the exhaust cylinder, the fixed dead center of the casing, and the front-end guiding sliding support. The dead center of the exhaust cylinder is arranged on the low-pressure exhaust cylinder of the steam turbine. The fixed dead center of the casing is fixedly arranged at one end of the exhaust device casing close to the exhaust pipe of the air-cooled island. The sliding support is slidably arranged at one end of the exhaust device casing close to the low-pressure exhaust cylinder of the steam turbine.

[0040] Specifically: The axial centerlines of the low-pressure exhaust cylinder of the steam turbine and the exhaust device casing are collinear. The front end of the casing is rigidly connected to the exhaust cylinder through a flange, and the rear end is welded to the exhaust pipe of the air-cooled island through a collar. Two groups of front-end expansion joints and one group of rear-end expansion joints are respectively arranged at both ends of the casing, and the two are connected by four groups of tie rods. A hot well is suspended directly below the casing. The support system includes the dead center of the exhaust cylinder, the fixed dead center of the casing, and the front-end guiding sliding support.

[0041] The dead center of the exhaust cylinder is fixed at the bottom of the exhaust cylinder, restricting its radial and axial degrees of freedom. The fixed dead center of the casing is welded to the rear end of the casing, serving as the fixed reference for the entire device. The sliding support is installed at the front end of the casing, allowing the casing to slide axially but restricting radial offset.

[0042] During the operation of the unit, the vacuum force of the air-cooled island is transmitted to the rear-end expansion joint through the exhaust pipe, and then conducted to the front-end expansion joint and the exhaust cylinder through the tie rods, forming a rigid force chain of "steam turbine - exhaust device - air-cooled island", so that the fixed dead center of the casing only bears its own weight, avoiding the direct action of the vacuum thrust on the support structure.

[0043] Through the "self-balancing of the force chain" design, the drawback of the need for an additional thrust bearing to bear the vacuum force in the traditional device is eliminated, improving the operating safety of the unit.

[0044] Furthermore, there are four groups of multiple tie rods, evenly distributed around the casing at intervals of 90°. Both ends of each group of tie rods are hinged to the expansion joint through cylindrical pins.

[0045] The four groups of tie rods are evenly distributed around the casing at intervals of 90°. Both ends of each group of tie rods are hinged to the flange ear plates of the front and rear expansion joints through cylindrical pins, forming a rotatable hinge support connection.

[0046] One end of the tie rod is hinged to the outer flange of the rear-end expansion joint, and the other end is hinged to the inner flange of the front-end expansion joint, forming a spatial force balance structure through symmetric arrangement.

[0047] When the axial vacuum thrust is generated in the air-cooled island, the four groups of tie rods are simultaneously tensioned, evenly transmitting the force to the exhaust cylinder, and using the symmetric layout to offset the radial component force, avoiding the skew of the casing. The hinged structure allows the tie rod to rotate slightly with the expansion joint, adapting to the angular change during the thermal expansion process.

[0048] The uniform distribution design enables the thrust to be dispersed and transmitted, avoiding local stress concentration. At the same time, the hinge support structure ensures the flexibility of force transmission and does not hinder the displacement compensation function of the expansion joint.

[0049] Furthermore, a limiting clamp is provided in the middle of the tie rod. One end of the clamp is welded to the housing to limit the axial displacement of the tie rod within a reasonable range.

[0050] A limiting clamp is sleeved on the middle of the tie rod. One end of the clamp is welded to the outer surface of the housing, and the other end holds the tie rod tightly through a bolt. A position corresponding to the tie rod is set with a diameter slightly smaller than the inner diameter of the clamp, allowing the tie rod to have a small axial movement clearance range within the clamp.

[0051] The clamp is rigidly connected to the housing, forming a radial constraint on the tie rod to limit its excessive swing or deviation.

[0052] During normal operation, the tie rod moves axially slightly within the clearance allowed by the clamp to adapt to the displacement compensation of the expansion joint; when the unit starts or stops or the load changes suddenly, causing abnormal movement of the tie rod, the clamp limits its axial displacement within a safe range to prevent the expansion joint from being overstretched or compressed.

[0053] Through the limiting design, not only the force transmission function of the tie rod is ensured, but also the expansion joint is prevented from failing due to excessive displacement, improving the structural reliability.

[0054] Furthermore, the front-end expansion joint includes two groups, which are used to compensate for axial displacement and absorb radial vibration; the rear-end expansion joint is a single-layer bellows.

[0055] The front-end expansion joint is two groups of juxtaposed stainless steel bellows. Each group contains a multi-layer corrugated structure, which can compensate for axial displacement bidirectionally and absorb radial vibration; the rear-end expansion joint is a single-layer bellows with a lower stiffness, which is only used for axial displacement compensation.

[0056] The front-end expansion joint is directly connected to the exhaust cylinder flange, and the rear-end expansion joint is welded to the air-cooled island pipeline. The two are axially tightened through a tie rod.

[0057] When the steam turbine is running, the exhaust cylinder expands axially due to temperature rise (along the housing axis towards the air-cooled island direction). The front double expansion joint absorbs the displacement through corrugation deformation; at the same time, the radial displacement caused by the vibration of the unit is buffered by the flexible structure of the double expansion joint. The rear single-layer expansion joint balances the axial unbalanced displacement not fully absorbed by the front end, and realizes the overall thermal expansion coordination through the linkage of the tie rod.

[0058] The differential design enables the front-end expansion joint to take into account both "strong compensation" and "vibration resistance", and the rear-end expansion joint simplifies the structure and reduces costs, jointly realizing the all-directional thermal displacement guidance.

[0059] Furthermore, the dead point of the exhaust cylinder is a boss-groove fit structure, where the boss is fixed to the bottom of the exhaust cylinder and the groove is embedded in the foundation platform.

[0060] The dead point of the exhaust cylinder is a "boss-groove" fit structure. The boss is welded to the bottom of the exhaust cylinder, and the groove is pre-embedded in the foundation platform. The boss is embedded in the groove to form radial and axial limiting constraints.

[0061] The contact surface between the boss and the groove is a combination of a horizontal plane and a vertical plane, which restricts the degrees of freedom of the exhaust cylinder in the XY plane (radial direction) and the Z-axis (axial direction), and only allows a slight lift in the vertical direction (Z-axis) due to thermal expansion.

[0062] The dead point serves as the thermal expansion reference point for the entire unit, fixing the spatial position of the exhaust cylinder and forcing the thermal expansion displacement of the shell to occur only axially (in the direction of the air-cooled island). Through the cooperation of the front sliding support and the rear fixed dead point, the entire device is guided to expand in the designed direction, avoiding disordered displacement.

[0063] Defining the thermal expansion reference ensures the coordinated displacement of each component and prevents structural stress concentration caused by chaotic expansion directions.

[0064] Furthermore, the sliding support includes an axial chute fixed to the foundation and a slider welded to the shell. When the shell undergoes thermal expansion, the slider can slide axially in the axial chute and restricts the radial displacement of the shell.

[0065] Component setting: The sliding support includes an axial chute (extending along the axis of the shell) fixed to the foundation and a slider welded to the front end of the shell. The chute and the slider are in a T-shaped fit, and limit baffles are provided on both sides of the chute to restrict the radial movement of the slider.

[0066] The slider is inserted into the chute and is allowed to slide axially (along the axis of the shell), but its radial (perpendicular to the axis direction) displacement is restricted by the baffle.

[0067] When the shell expands towards the air-cooled island due to temperature rise, the slider slides freely in the chute, releasing the axial thermal stress; at the same time, the limit baffle prevents the shell from undergoing radial offset, ensuring that the expansion path is strictly along the axis direction, forming a "single-point fixation - single-point guidance" expansion system with the constraint of the exhaust cylinder dead point.

[0068] The guiding design ensures the directionality of the shell expansion, avoids stress concentration at the pipe interface caused by radial swaying, and improves the connection reliability.

[0069] Furthermore, it includes a hot well skirt and spring supports. The upper end of the spring support is connected to the skirt, the lower end is connected to the hot well, and the hot well skirt is connected to the shell. There are at least two spring supports.

[0070] The top of the hot well is vertically welded to the bottom of the shell through the skirt. At least two spring supports are evenly distributed below the skirt. The upper end of the spring support is connected to the skirt, and the lower end is fixed to the foundation. The spring can be compressed and deformed to absorb the thermal displacement in the vertical direction.

[0071] The skirt support is a ring-shaped steel structure that transfers the weight of the hot well to the shell and the spring support; the elastic elements (such as helical springs) of the spring support provide flexible support, allowing the hot well to rise and fall slightly as the shell expands vertically due to heat.

[0072] When the shell expands vertically due to temperature rise, the spring support absorbs the relative displacement between the shell and the hot well through elastic deformation, avoiding stress concentration caused by rigid connection; at the same time, the pre-tightening force of the spring ensures the stable load-bearing of the hot well during normal operation and releases the gravity load during shutdown.

[0073] The flexible support design reduces the additional bending moment of the hot well on the shell, while ensuring the sealing of the drain pipe connection and avoiding water leakage problems caused by displacement differences.

[0074] Furthermore, a hot well limit device is provided along the outer facade of the steam turbine axis to ensure smooth thermal expansion of the exhaust steam device.

[0075] The hot well limit device is arranged on the outer facade of the hot well and consists of a guide rod fixed to the shell and a limit sleeve welded to the hot well. The guide rod is inserted into the limit sleeve, allowing relative sliding along the axial direction of the shell between the two, but restricting radial offset.

[0076] The guide rod is rigidly connected to the shell, and the limit sleeve is fixed to the hot well, forming a "rod - sleeve" sliding pair with a clearance of 2 - 3 mm.

[0077] When the shell expands axially, the hot well maintains relative sliding with the shell through the limit device. The guide rod restricts the radial displacement of the hot well, ensuring its synchronous axial movement with the shell and avoiding distortion or tearing of the pipeline interface caused by different expansion rates between the two.

[0078] The limit device ensures the expansion coordination between the shell and the hot well, prevents damage to the drain pipe due to displacement differences, and improves the system sealing performance.

[0079] Furthermore, a return water nozzle assembly is provided in the hot well.

[0080] The return water nozzle assembly is arranged above the interior of the hot well and includes multiple groups of low-pressure membrane nozzles. The nozzle inlets are connected to the condensate pipes of the air-cooled island, and the outlets spray obliquely upward to form a thin sheet of water film.

[0081] The nozzles are fixed to the inner wall of the hot well by flanges. The condensate is pumped through the pipes to the nozzles and directly contacts the exhaust steam of the steam turbine inside the shell (flowing into the space above the hot well from the top of the shell).

[0082] The low-temperature condensed water returned from the air-cooled island is atomized into a film through a nozzle and undergoes sufficient heat exchange with the high-temperature exhaust steam (about 45 °C). The latent heat released by the condensation of the exhaust steam heats the condensed water, and at the same time, the dissolved oxygen in the water is removed through gas-liquid contact; the drain water flows into the bottom of the hot well from the steam turbine body and pipelines. After flashing, the flash steam returns to the air-cooled island through the pipeline at the top of the shell, and the condensed water is pumped to the regenerative system.

[0083] The film-type contact increases the heat transfer area, enhances the effect of regenerative deaeration, eliminates the need for a traditional independent deaerator, shortens the drain water path, and improves the quality of the condensed water and the thermal efficiency of the system.

[0084] Furthermore, a three-stage desuperheating and pressure-reducing device is provided on the outer side of the shell.

[0085] A three-stage desuperheating and pressure-reducing device is provided on the outer side of the shell, which are in turn a Venturi injection section (for preliminary pressure reduction), a porous throttling section (for refining the flow path and cooling), and a surface cooling section (for final cooling by spraying and atomizing). The inlet is connected to the emergency exhaust steam pipeline of the steam turbine, and the outlet is connected to the air-cooled island or the drain water system.

[0086] The device is integrally designed with the shell, the pipeline interface is welded to the side wall of the shell, and the internal flow path is connected to the exhaust steam space of the shell.

[0087] When the unit starts up, shuts down, or operates at low load, the high-temperature and high-pressure exhaust steam (such as 550 °C, 1.5 MPa) first accelerates and reduces pressure through the Venturi section, then cools down through the throttling of the perforated plate, and finally mixes with the atomized water in the surface cooling section, and is reduced to a temperature acceptable to the air-cooled island (about 120 °C, 0.1 MPa), avoiding thermal shock to the air-cooled island under extreme working conditions.

[0088] The three-stage treatment gradually reduces the temperature and pressure, quickly responds to changes in working conditions, protects the air-cooled island equipment, meets the requirements of frequent start-up and shutdown of the solar thermal power generation unit, and extends the service life of the core components.

[0089] The above are only the preferred embodiments of the invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A large-scale solar thermal steam turbine axial exhaust device, characterized in that: It comprises a steam turbine low-pressure exhaust cylinder (15), an exhaust device shell (3), an air-cooling island exhaust pipe, a hot water well (12) and a support system, wherein the exhaust device shell (3) is provided with a front expansion joint (1) and a rear expansion joint (5) at both ends, and the front and rear expansion joints are connected by a plurality of tie rods (2); The exhaust device shell (3) is colinear with the axial center line of the low-pressure exhaust cylinder (15) of the steam turbine, the front end is connected to the exhaust cylinder (15) via a flange, and the rear end is welded to the air-cooling island exhaust pipe via a connecting ring; the hot water well (12) is arranged below the shell (3); The support system comprises an exhaust cylinder dead point (16), a shell fixed dead point (7), and a front guide sliding support (14); the exhaust cylinder dead point (16) is arranged on a low-pressure exhaust cylinder (15) of a steam turbine; the shell fixed dead point (7) is fixedly arranged on an exhaust device shell (3) close to one end of an exhaust pipe of an air-cooled island; and the sliding support (14) is slidably arranged on an exhaust device shell (3) close to one end of a low-pressure exhaust cylinder (15) of a steam turbine.

2. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: The plurality of tie rods (2) are divided into four groups and are evenly distributed at intervals of 90 degrees on the periphery of the shell (3). Both ends of each group of tie rods (2) are hinged to the expansion joint via cylindrical pins (6).

3. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: A limiting clamp (4) is provided in the middle of the pull rod (2), and one end of the clamp (4) is welded to the housing (3) to limit the axial displacement of the pull rod (2) within a reasonable range.

4. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: The front end expansion joint (1) comprises two groups, which are used to compensate for axial displacement and absorb radial vibration; the rear end expansion joint (5) is a single-layer bellows.

5. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: The exhaust cylinder dead point (16) is a boss-groove matching structure, the boss is fixed to the bottom of the exhaust cylinder, and the groove is embedded in the base platform.

6. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: The sliding support (14) comprises an axial sliding groove fixed to a base and a sliding block (17) welded to the shell (3); when the shell (3) undergoes thermal expansion, the sliding block (17) can slide axially along the shell in the axial sliding groove and limit radial displacement of the shell.

7. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: It comprises a hot water well skirt (8) and a spring support (9), wherein the upper end of the spring support (9) is connected to the skirt (8) and the lower end is connected to the hot water well (12), the hot water well skirt (8) is connected to the shell (3), and the spring support (9) comprises at least two.

8. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: The hot water well (12) is provided with a hot water well limiting device (10) along the axial outer facade of the steam turbine to ensure smooth thermal expansion of the exhaust device.

9. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: The hot water well (12) is provided with a water return nozzle assembly (11).

10. According to the large-scale solar thermal steam turbine axial exhaust device described in claim 1, it is characterized by: A three-stage temperature and pressure reduction device (13) is arranged outside the shell (3).

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