Double-machine regenerative steam turbine unit

Abstract

The utility model discloses a double-unit regenerative turboset, and relates to the technical field of turbines. The problems that the irreversible loss is increased and the manufacturing cost is increased when a regenerative system extracts steam along with the increase of steam parameters in the prior art are solved. The system comprises a main steam turbine and a small steam turbine, the main steam turbine comprises an ultrahigh-pressure cylinder, a steam inlet of the small steam turbine is connected with a high-pressure steam guide pipe, an inlet of the high-pressure steam guide pipe is connected with a main steam adjusting valve, a steam inlet of the main steam adjusting valve is communicated with a steam outlet of the ultrahigh-pressure cylinder, and a steam outlet of the main steam adjusting valve is communicated with a steam outlet of the ultrahigh-pressure cylinder. The small steam turbine is used for driving the feed pump to operate, steam firstly enters the ultrahigh-pressure cylinder to do work, part of steam discharged from the ultrahigh-pressure cylinder is used for driving the small steam turbine and driving the feed pump to supply water to the boiler, and meanwhile extracted steam and exhausted steam of the small steam turbine serve as regenerative extracted steam and return to a regenerative system of the main steam turbine to heat condensed water and feed water. The steam temperature after acting of the small steam turbine is lower, loss can be reduced, and the overall heat efficiency of the unit is improved.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine technology, specifically to a dual-unit regenerative steam turbine. Background Technology

[0002] As steam parameters increase in conventional steam turbines, the superheat of the extracted steam in the regenerator system increases, and the temperature difference between the steam and water sides in the regenerator heater becomes larger. Due to the increased irreversible heat exchange losses, the benefits brought by the increase in steam parameters are weakened.

[0003] Meanwhile, the high steam temperature increases the manufacturing costs of pipes, valves, and heaters, resulting in poor economic benefits.

[0004] In summary, existing regenerative systems suffer from increased irreversible losses and rising manufacturing costs when extracting steam as steam parameters increase. Utility Model Content

[0005] The purpose of this invention is to address the problems of increased irreversible losses and rising manufacturing costs in existing regenerative steam systems when extracting steam as steam parameters increase. The invention provides a dual-unit regenerative steam turbine unit.

[0006] The technical solution of this utility model is: a dual-machine regenerative steam turbine unit, comprising: a main steam turbine, wherein the main steam turbine includes an ultra-high pressure cylinder;

[0007] A small steam turbine is provided, with a high-pressure steam pipe connected to its steam inlet. A main steam regulating valve is connected to the inlet of the high-pressure steam pipe. The steam inlet of the main steam regulating valve is connected to the exhaust port of the ultra-high pressure cylinder. The small steam turbine is used to drive the feedwater pump.

[0008] The extraction port and exhaust port of the small steam turbine are respectively connected to the regenerative system of the main steam turbine.

[0009] Furthermore, it also includes: a power generation device connected to the output end of the small steam turbine.

[0010] Furthermore, the main steam regulating valve has two valves symmetrically distributed on both sides of the cylinder of the small steam turbine.

[0011] Furthermore, when the main steam turbine is not started, the steam inlet of the small steam turbine is connected to the exhaust port of the auxiliary boiler through a switching device. After the main steam turbine is started, the steam inlet of the small steam turbine is connected to the exhaust port of the main steam turbine through a switching device.

[0012] Furthermore, the two main steam regulating valves are fixedly mounted on both sides of the cylinder by rigid brackets.

[0013] Furthermore, the small steam turbine includes a front bearing housing, a rear bearing housing, an outer cylinder, an inner cylinder, a first diaphragm sleeve, a second diaphragm sleeve, a third diaphragm sleeve, a fourth diaphragm sleeve, a front steam seal, a rear steam seal, a balance ring, a rotor, a diaphragm coupling, a thrust support combined bearing, a support bearing, a turning gear, a frame, stationary blades, and moving blades. The front bearing housing and the rear bearing housing are respectively fixedly installed on the frame. The main steam regulating valve is connected to the outer cylinder through a high-pressure steam pipe. The outer cylinder is supported by an upper cat claw and is connected to the front bearing housing and the rear bearing housing respectively through a vertical key.

[0014] The thrust support combined bearing is installed in the front bearing housing, the support bearing is installed in the rear bearing housing, the rotor is supported on the thrust support combined bearing and the support bearing, the moving blades are installed on the corresponding flow passage of the rotor, the front steam seal and the rear steam seal are respectively installed at the front and rear ends of the outer cylinder, the inner cylinder, the first diaphragm sleeve, the second diaphragm sleeve, the third diaphragm sleeve and the fourth diaphragm sleeve are all installed inside the outer cylinder, and the stationary blades are respectively installed on the inner cylinder, the first diaphragm sleeve, the second diaphragm sleeve, the third diaphragm sleeve and the fourth diaphragm sleeve;

[0015] The turning device is installed on the top of the rear bearing housing and connected to the rotor inside the rear bearing housing.

[0016] Furthermore, the absolute dead point is located on the front bearing housing.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The dual-unit regenerative steam turbine provided by this utility model first enters the ultra-high pressure cylinder to do work. The steam discharged from the ultra-high pressure cylinder is used to drive the small steam turbine, which drives the feedwater pump to supply water to the boiler. At the same time, the extraction and exhaust steam of the small steam turbine is used as regenerative extraction steam and returns to the regenerative system of the main steam turbine to heat the condensate and feedwater. The steam temperature after the small steam turbine does work is lower, which can reduce losses and improve the overall thermal efficiency of the unit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the small steam turbine of this utility model;

[0020] Figure 2 yes Figure 1 Top view;

[0021] Figure 3 yes Figure 1 A sectional view;

[0022] In the diagram: 1. Main steam regulating valve; 2. High-pressure steam pipe; 3. Front bearing housing; 4. Rear bearing housing; 5. Outer cylinder; 6. Inner cylinder; 7. First diaphragm sleeve; 8. Second diaphragm sleeve; 9. Third diaphragm sleeve; 10. Fourth diaphragm sleeve; 11. Front steam seal; 12. Rear steam seal; 13. Balance ring; 14. Rotor; 15. Diaphragm coupling; 16. Thrust support combined bearing; 17. Support bearing; 18. Turning gear; 19. Frame; 20. Stationary blade; 21. Moving blade. Detailed Implementation

[0023] Specific implementation method one: Combining Figure 1 , Figure 2 This embodiment describes a main steam turbine and a small steam turbine. The main steam turbine includes an ultra-high pressure cylinder. A high-pressure steam pipe 2 is connected to the steam inlet of the small steam turbine. A main steam regulating valve 1 is connected to the inlet of the high-pressure steam pipe 2. The steam inlet of the main steam regulating valve 1 is connected to the exhaust port of the ultra-high pressure cylinder. The small steam turbine is used to drive the feedwater pump. The extraction steam port and exhaust steam port of the small steam turbine are respectively connected to the regenerative system of the main steam turbine. In this embodiment, the small steam turbine is a back-extraction feedwater pump turbine. The extraction steam and exhaust steam of the small steam turbine are used as regenerative extraction steam and returned to the regenerative system of the main steam turbine.

[0024] In this embodiment of the dual-unit regenerative steam turbine, steam first enters the ultra-high pressure cylinder to do work. The steam discharged from the ultra-high pressure cylinder is used to drive the small steam turbine, which in turn drives the feedwater pump to supply water to the boiler. At the same time, the extraction and exhaust steam from the small steam turbine is used as regenerative extraction steam and returns to the regenerative system of the main steam turbine to heat the condensate and feedwater. The steam temperature after being done by the small steam turbine is lower, which can reduce losses and improve the overall thermal efficiency of the unit.

[0025] Specific Implementation Method Two: Combining Figure 1 , Figure 2 This embodiment differs from specific embodiment one in that it further includes a power generation device connected to the output end of the small steam turbine. The power generation device can be a variable frequency generator. During stable operation of the unit, the unit's output drives the feedwater pump, and the remaining power drives the variable frequency motor to generate electricity, thus fully utilizing steam to perform work and increasing power generation. Other components and connections are the same as in specific embodiment one.

[0026] Specific implementation method three: Combining Figure 1 , Figure 2This embodiment differs from specific embodiment one in that the main steam regulating valve 1 has two valves symmetrically distributed on both sides of the cylinder of the small steam turbine. The two main steam regulating valves 1 not only allow for a larger steam intake, but also ensure that if one valve fails, the other can still guarantee the normal operation of the unit without requiring shutdown for maintenance, thus ensuring full utilization of steam. Other components and connections are the same as in specific embodiment one.

[0027] Specific implementation method four: Combination Figure 1 , Figure 2 This embodiment differs from Specific Embodiment Three in that, when the main steam turbine is not started, the steam inlet of the small steam turbine is connected to the exhaust port of the auxiliary boiler via a switching device. After the main steam turbine starts, the steam inlet of the small steam turbine is connected to the exhaust port of the main steam turbine via the switching device. The switching device can be a converter, and the exhaust steam from the auxiliary boiler can be preheated to adjust the small steam turbine to its optimal operating state. Other components and connections are the same as in Specific Embodiment Three.

[0028] Specific Implementation Method Five: Combining Figure 1 , Figure 2 This embodiment differs from Specific Embodiment Three in that the two main steam regulating valves 1 are fixedly mounted on both sides of the cylinder by rigid brackets. These rigid brackets have minimal elastic deformation, strictly limiting the axial and radial displacement and deflection of the main steam regulating valves 1. This ensures precise alignment of the flange and sealing surface of the main steam regulating valve 1 outlet with the cylinder inlet, preventing steam leakage or excessive pipeline stress due to misalignment. Other components and connections are the same as in Specific Embodiment Three.

[0029] Specific Implementation Method Six: Combination Figure 3This embodiment differs from specific embodiment one in that the small steam turbine includes a front bearing housing 3, a rear bearing housing 4, an outer cylinder 5, an inner cylinder 6, a first diaphragm sleeve 7, a second diaphragm sleeve 8, a third diaphragm sleeve 9, a fourth diaphragm sleeve 10, a front steam seal 11, a rear steam seal 12, a balance ring 13, a rotor 14, a diaphragm coupling 15, a thrust support combined bearing 16, a support bearing 17, a turning gear 18, a frame 19, stationary blades 20, and moving blades 21. The front bearing housing 3 and the rear bearing housing 4 are respectively fixedly mounted on the frame 19. The main steam regulating valve 1 is connected to the outer cylinder 5 through a high-pressure steam pipe 2. The outer cylinder 5 is supported by upper cat claws and connected to the front bearing housing 3 and the rear bearing housing 4 respectively through vertical keys. The thrust support combined bearing 16 is installed in the front bearing housing 3, and the support bearing 17 is installed in the rear bearing housing 4. The rotor 14 is supported on the thrust support. On the combined bearing 16 and the support bearing 17, the moving blades 21 are installed on the corresponding flow passage of the rotor 14. The front steam seal 11 and the rear steam seal 12 are respectively installed on the front and rear ends of the outer cylinder 5. The inner cylinder 6, the first diaphragm sleeve 7, the second diaphragm sleeve 8, the third diaphragm sleeve 9, and the fourth diaphragm sleeve 10 are all installed inside the outer cylinder 5. The stationary blades 20 are respectively installed on the inner cylinder 6, the first diaphragm sleeve 7, the second diaphragm sleeve 8, the third diaphragm sleeve 9, and the fourth diaphragm sleeve 10. The turning gear 18 is installed on the top of the rear bearing housing 4 and connected to the rotor 14 inside the rear bearing housing 4. A balance ring 13 is provided to balance the axial thrust generated by the reaction flow before the rotating diaphragm. The thrust generated by the pressure difference at both ends of the balance drum is balanced with the thrust generated by the reaction flow of the unit. When the main steam parameters change, the change in thrust at both ends of the balance drum cancels out the change in thrust at both ends of the reaction flow. Other components and connections are the same as any one of the specific embodiments one to five.

[0030] Specific implementation method seven: Combining Figure 1 This embodiment differs from specific embodiment six in that the absolute dead point is set on the front bearing housing 3. After the turbine starts, the outer cylinder 5 expands along the turbine axis towards the rear bearing housing 4 with the front bearing housing 3 as the dead point. The rotor 14 expands towards the rear bearing housing 4 with the thrust-supported combined bearing 16 as the dead point, ensuring that the expansion directions of the rotor 14 and the outer cylinder 5 are consistent and minimizing the expansion difference. Other components and connections are the same as in specific embodiment six.

[0031] The content of this utility model is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the utility model.

Claims

1. A dual-unit regenerative steam turbine unit, characterized in that, include: The main steam turbine includes an ultra-high pressure cylinder; The small steam turbine has a high-pressure steam pipe (2) connected to its steam inlet. The main steam regulating valve (1) is connected to the inlet of the high-pressure steam pipe (2). The steam inlet of the main steam regulating valve (1) is connected to the exhaust port of the ultra-high pressure cylinder. The small steam turbine is used to drive the feedwater pump. The extraction port and exhaust port of the small steam turbine are respectively connected to the regenerative system of the main steam turbine.

2. The dual-unit regenerative steam turbine unit according to claim 1, characterized in that, Also includes: The power generation equipment is connected to the output end of the small steam turbine.

3. The dual-unit regenerative steam turbine unit according to claim 1, characterized in that, The main steam regulating valve (1) has two valves symmetrically distributed on both sides of the cylinder of the small steam turbine.

4. A dual-unit regenerative steam turbine unit according to claim 3, characterized in that, When the main steam turbine is not started, the steam inlet of the small steam turbine is connected to the exhaust port of the auxiliary boiler through a switching device. After the main steam turbine is started, the steam inlet of the small steam turbine is connected to the exhaust port of the main steam turbine through a switching device.

5. A dual-unit regenerative steam turbine unit according to claim 3, characterized in that, The two main steam regulating valves (1) are fixedly installed on both sides of the cylinder by rigid brackets.

6. A dual-unit regenerative steam turbine unit according to any one of claims 1-5, characterized in that, The small steam turbine includes a front bearing housing (3), a rear bearing housing (4), an outer cylinder (5), an inner cylinder (6), a first diaphragm sleeve (7), a second diaphragm sleeve (8), a third diaphragm sleeve (9), a fourth diaphragm sleeve (10), a front steam seal (11), a rear steam seal (12), a balance ring (13), a rotor (14), a diaphragm coupling (15), a thrust support combined bearing (16), a support bearing (17), a turning gear (18), a frame (19), stationary blades (20), and moving blades (21). The front bearing housing (3) and the rear bearing housing (4) are respectively fixedly installed on the frame (19). The main steam regulating valve (1) is connected to the outer cylinder (5) through a high-pressure steam pipe (2). The outer cylinder (5) is supported by upper cat claws and is connected to the front bearing housing (3) and the rear bearing housing (4) respectively through vertical keys. The thrust support combined bearing (16) is installed in the front bearing housing (3), the support bearing (17) is installed in the rear bearing housing (4), the rotor (14) is supported on the thrust support combined bearing (16) and the support bearing (17), the moving blade (21) is installed in the flow passage part corresponding to the rotor (14), the front steam seal (11) and the rear steam seal (12) are respectively installed at the front and rear ends of the outer cylinder (5), the inner cylinder (6), the first diaphragm sleeve (7), the second diaphragm sleeve (8), the third diaphragm sleeve (9) and the fourth diaphragm sleeve (10) are all installed inside the outer cylinder (5), and the stationary blade (20) is respectively installed on the inner cylinder (6), the first diaphragm sleeve (7), the second diaphragm sleeve (8), the third diaphragm sleeve (9) and the fourth diaphragm sleeve (10); The turning device (18) is installed on the top of the rear bearing housing (4) and is connected to the rotor (14) inside the rear bearing housing (4).

7. A dual-unit regenerative steam turbine unit according to claim 6, characterized in that, The absolute dead point is set on the front bearing housing (3).

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