A steam turbine throttling extraction steam regulation system and its working method

Abstract

This invention belongs to the field of steam turbines, specifically disclosing a steam turbine throttling extraction steam regulation system and its working method. The aim is to address the current limitation that only extraction steam regulation valve structures are suitable for reaction turbine units, thereby achieving adjustable steam extraction within the limited space of a reaction turbine. This invention incorporates a rotating baffle in the throttling extraction steam regulation system. A holding ring with a holding window and a rotating ring with a rotating window are fixed between the holding ring and the baffle ring by a cover ring. When external steam demand is required, the stroke of the hydraulic actuator is adjusted, controlling the connecting rod to move the rotating ring. A flow channel is formed between the holding ring window and the rotating ring window. By changing the flow area, the pressure is controlled, thus meeting the external steam demand of the unit. This invention is applicable to reaction turbines with a compact structure, occupies less axial space, and achieves stable industrial extraction steam pressure when the turbine operates under different conditions.

Description

Technical Field

[0001] This invention belongs to the field of steam turbines, and specifically relates to a steam turbine throttling extraction steam regulation system and its working method. Background Technology

[0002] In the field of industrial steam turbines, users often have a demand for industrial steam. Therefore, steam turbines need to be equipped with extraction steam regulating mechanisms to ensure the stability of industrial extraction steam pressure when the steam turbine is operating under different conditions. Existing extraction steam regulating mechanisms include impulse rotary diaphragms and extraction steam regulating valves. However, only the extraction steam regulating valve structure is suitable for reaction-type units.

[0003] With the widespread use of reaction-type flow passage structures, the original extraction steam regulating valve structure requires a large axial space, which reduces the space available for other flow passage structures within the same span, limiting the increase in flow passage stages and thus limiting the improvement of turbine cylinder efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a steam turbine throttling extraction regulating system and its operating method. This throttling extraction regulating system incorporates an adjustable window throttling rotating baffle to achieve adjustable steam extraction within the limited space of a reaction steam turbine, providing a new approach for the design of adjustable steam extraction in reaction steam turbines.

[0005] To achieve the objective of this invention, the technical solution adopted is as follows:

[0006] A steam turbine throttling extraction regulating system includes a rotating baffle, a connecting rod 5, an extraction chamber 6, a mixing chamber 7, a cylinder 8, and a hydraulic actuator 9; wherein the rotating baffle includes a holding ring 1, a rotating ring 2, a cover ring 3, a holding ring window 4, and a rotating ring window 10.

[0007] Among them, the holding ring 1 is a circular ring structure, and the holding ring 1 is provided with a holding ring window 4. The holding ring 1 and the holding ring window 4 are integrally formed. The holding ring window 4 is evenly distributed around the central axis of the holding ring 1, and the circumference of the holding ring 1 with the holding ring window 4 is convex.

[0008] Furthermore, the retaining ring 1 consists of upper and lower parts, which are connected by bolts.

[0009] Furthermore, the number of ring-holding windows 4 is 12 to 16, preferably 14.

[0010] Furthermore, the total area of ​​the ring-holding window 4 is 2 to 2.5 times the flow area of ​​the next stage stationary blade, preferably 2.2 times; to meet the flow capacity under maximum power conditions.

[0011] Furthermore, the height of the holding window 4 is 1.1 to 1.5 times the height of the next stage stationary blade, preferably 1.3 times; to ensure smooth flow and reduce pressure loss.

[0012] Among them, the rotating ring 2 is a circular ring structure, and the rotating ring 2 is provided with rotating ring windows 10, which are evenly distributed around the central axis of the rotating ring 2.

[0013] Furthermore, the rotating ring 2 has a protrusion with a hole.

[0014] Furthermore, the swivel ring 2 includes an upper half-ring arc segment and a lower half-ring arc segment, which are connected by bolts.

[0015] Furthermore, the holding window 4 and the rotating window 10 are the same size.

[0016] Furthermore, the number of holding windows 4 and rotating windows 10 are the same.

[0017] The holding window 4 and the rotating window 10 form a flow channel, and the rotation angle of the rotating window can be adjusted to be fully open or fully closed. By cooperating with the holding window 4 and the rotating window 10, the flow area is changed, thereby achieving the effect of controlling the pressure and meeting the external steam demand of the unit.

[0018] Furthermore, the positions of the holding window 4 and the rotating window 10 are in a one-to-one correspondence when they are fully open;

[0019] Furthermore, when the holding window 4 and the rotating window 10 are fully closed, at least 1° of window area is maintained to ensure the minimum flow through the last stage blades and ensure safe operation.

[0020] Furthermore, the contact area between the retaining ring 1 and the rotating ring 2 is under working conditions with stress lower than the allowable stress of the material, and the gap is 0.4mm~0.6mm, preferably 0.5mm, to ensure that the rotating ring does not get stuck and achieve a good sealing effect.

[0021] Furthermore, the contact surface between the holding ring 1 and the rotating ring 2 is strengthened through nitriding to ensure that the mechanism will not fail during long-term operation.

[0022] The cover ring 3 has an arc-shaped segmented structure. The cover ring 3 is bolted to the holding ring 1, fixing the rotating ring 2 between the holding ring 1 and the cover ring 3. This serves to limit the axial movement of the rotating ring while not hindering its circumferential rotation.

[0023] Furthermore, the gap between the rotating ring 2 and the cover ring 3 is 0.4mm~0.6mm, preferably 0.5mm.

[0024] The connecting rod 5 is positioned between the rotating ring 3 and the hydraulic motor 9, and is connected to the rotating ring 3 and the hydraulic motor 9 through a perforated protrusion on the rotating ring 2; this ensures the adjustment of the window area while taking into account the strength and fatigue of the connecting rod, so as to meet the requirements of long-term stable operation of the steam turbine under varying operating conditions.

[0025] Among them, the extraction chamber 6 is located in front of the rotating window 10; the mixing chamber 7 is located between the holding window 4 and the stationary vane;

[0026] Furthermore, the ratio of the cross-sectional area of ​​the mixing chamber 7 to the annular area of ​​the next stage stationary blade inlet is greater than 0.2; after the steam passes through the window, it needs to be fully mixed in the mixing chamber to ensure that the steam is uniform throughout the circumference when it enters the next stage stationary blade to do work.

[0027] Among them, the stationary blade is installed in the cylinder 8 through the retaining ring 1, and together with the rotor impeller, it forms the turbine flow passage.

[0028] The working method of the steam turbine throttling extraction regulating mechanism provided by the present invention:

[0029] (1) During installation, first adjust the swivel and connecting rod to the fully open position, and connect the hydraulic motor to stabilize it in that position;

[0030] (2) When the unit is started, the rotating window and the holding window are fully open. At this time, the window area meets the full flow capacity, and all the steam passes through the turbine to do work.

[0031] (3) When the unit needs steam outside, it enters the steam supply mode, adjusts the oil motor stroke, controls the connecting rod to drive the rotating ring to rotate, and adjusts the window area between the rotating ring window and the holding ring window; with the adjustment of the window area, the throttling effect is achieved, and the pressure of the extraction chamber gradually increases. When the extraction steam pressure is higher than the pressure value in the extraction steam header of the heating network, the external steam supply pipeline valve is opened to connect the heat load and adjust the extraction point pressure to the required pressure.

[0032] (4) When the operation of the steam supply mode is switched to the pure condensing mode, the rotating diaphragm will be opened gradually in sequence, the heat load will be gradually reduced, and after the rotating diaphragm is fully opened, the external steam supply pipeline valve will be closed, and the unit will switch to pure condensing mode operation.

[0033] The above technical solution has the following beneficial effects:

[0034] 1. This invention integrates the adjustable window structure and the holding ring into a single unit. By adjusting the window area, throttling control is achieved, thereby controlling the extraction steam pressure and meeting the external steam demand of the unit.

[0035] 2. The present invention can effectively control the extraction steam pressure of the unit. Compared with the extraction steam regulating valve structure, the structure of the present invention greatly reduces the axial space occupied and reduces the difficulty of shaft system design. Therefore, it is particularly suitable for high-parameter, multi-stage, high-efficiency reaction steam turbines.

[0036] 3. By rationally designing the gaps between the rotating ring and the holding ring body and the cover ring, a better sealing effect is achieved while ensuring that the rotating ring does not jam. At the same time, the strength and fatigue of the rotating ring are considered to meet the long-term stable operation of the steam turbine under varying operating conditions.

[0037] 4. The rotating ring is limited by the upper and lower half-ring arc segments and the holding ring body. At the same time, the rotating ring is connected to the external hydraulic motor of the cylinder through the connecting rod. During operation, the hydraulic motor drives the connecting rod and the rotating ring to move, thereby changing the window area and achieving the throttling effect. This allows for adjustment of the steam extraction chamber pressure to meet the user's steam demand.

[0038] 5. The design of leaving at least 1° in the fully closed position allows the window to have a certain flow capacity, ensuring that the minimum flow rate through the last stage blades is guaranteed and the operation is safe by not fully closing the window.

[0039] 6. When starting the unit, the windows are fully open, allowing steam to flow through the entire flow path to prevent forced draft from the last-stage impeller, which could affect the safe operation of the unit. When the unit reaches a certain load, the hydraulic actuator drives the connecting rod to control the rotating ring, adjusting the window area. This increases the pressure in the extraction chamber before the window, raising it slightly above the heating network pressure, at which point the pipeline valves can be opened to supply steam to the users.

[0040] 7. The steam turbine throttling extraction regulating mechanism and its working method provided by the present invention are applicable to reaction flow, have a compact structure, occupy a small axial space, and, in conjunction with connecting rods and hydraulic actuators, achieve the stability of industrial extraction steam pressure when the steam turbine is running under different operating conditions by adjusting the window area of ​​the rotating diaphragm. Furthermore, the mechanism can be matched with various hydraulic control oil systems, has a wide range of applications, and is easy to use. Attached Figure Description

[0041] Figure 1 This is a structural diagram of a rotating partition.

[0042] Figure 2 A schematic diagram of the cross-section of the steam turbine throttling extraction regulating system;

[0043] Figure 3 This is a schematic diagram of the ring-holding structure;

[0044] Figure 4 This is a diagram showing the relative positions of the rotating ring and the holding ring when the rotating partition is fully closed.

[0045] In the diagram: 1-Holding ring, 2-Rotating ring, 3-Cover ring, 4-Window, 5-Connecting rod, 6-Extraction chamber, 7-Mixing chamber, 8-Cylinder, 9-Oil motor, 10-Rotating ring window. Detailed Implementation

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0047] Example 1

[0048] A steam turbine throttling extraction regulating system includes a rotating baffle, a connecting rod 5, an extraction chamber 6, a mixing chamber 7, a cylinder 8, and a hydraulic actuator 9; wherein the rotating baffle includes a holding ring 1, a rotating ring 2, a cover ring 3, a holding ring window 4, and a rotating ring window 10.

[0049] The retaining ring 1 has a circular structure and retaining ring windows 4. The retaining ring 1 and retaining ring windows 4 are integrally formed. The retaining ring windows 4 are evenly distributed around the central axis of the retaining ring 1. The circumference of the retaining ring 1 with retaining ring windows 4 is convex. The retaining ring 1 consists of upper and lower parts, which are connected by bolts. There are 14 retaining ring windows 4. The total area of ​​the retaining ring windows 4 is 2.2 times the flow area of ​​the next stage stationary blade. The height of the retaining ring windows 4 is 1.3 times the height of the next stage stationary blade.

[0050] The rotating ring 2 is a circular ring structure, and the rotating ring 2 is provided with rotating ring windows 10, which are evenly distributed around the central axis of the rotating ring 2. The rotating ring 2 includes an upper half-ring arc segment and a lower half-ring arc segment, which are connected by bolts. The holding ring window 4 and the rotating ring window 10 are the same size. The number of holding ring windows 4 and the rotating ring window 10 are the same.

[0051] The holding window 4 and the rotating window 10 form a flow channel, and the rotation angle of the rotating window can be adjusted to be fully open or fully closed; the holding window 4 and the rotating window 10 are in a one-to-one correspondence when fully open; and at least 1° of window area is retained when the holding window 4 and the rotating window 10 are fully closed.

[0052] The contact area between the retaining ring 1 and the rotating ring 2 is under working conditions with stress lower than the allowable stress of the material, and the gap is 0.5 mm. The contact surface between the retaining ring 1 and the rotating ring 2 is strengthened by nitriding.

[0053] The cover ring 3 has an arc-shaped segmented structure. The cover ring 3 is bolted to the holding ring 1, and the rotating ring 2 is fixed between the holding ring 1 and the cover ring 3. The gap between the rotating ring 2 and the cover ring 3 is 0.5mm.

[0054] The connecting rod 5 is positioned between the rotating ring 3 and the hydraulic motor 9, connecting the rotating ring 3 and the hydraulic motor 9;

[0055] The extraction chamber 6 is located in front of the rotating window 10;

[0056] The mixing chamber 7 is located between the holding window 4 and the stationary blade; the ratio of the cross-sectional area of ​​the mixing chamber 7 to the annular area of ​​the next stage stationary blade inlet is greater than 0.2;

[0057] The stationary blades are installed inside the cylinder 8 via the retaining ring 1, forming the turbine flow passage together with the rotor impeller.

[0058] Example 2

[0059] The working method of the steam turbine throttling extraction regulating mechanism provided by the present invention:

[0060] (1) During installation, first adjust the swivel and connecting rod to the fully open position, and connect the hydraulic motor to stabilize it in that position;

[0061] (2) When the unit is started, the rotating window and the holding window are fully open. At this time, the window area meets the full flow capacity, and all the steam passes through the turbine to do work.

[0062] (3) When the unit needs steam outside, it enters the steam supply mode, adjusts the oil motor stroke, controls the connecting rod to drive the rotating ring to rotate, and adjusts the window area between the rotating ring window and the holding ring window; with the adjustment of the window area, the throttling effect is achieved, and the pressure of the extraction chamber gradually increases. When the extraction steam pressure is higher than the pressure value in the extraction steam header of the heating network, the external steam supply pipeline valve is opened to connect the heat load and adjust the extraction point pressure to the required pressure.

[0063] (4) When the operation of the steam supply mode is switched to the pure condensing mode, the rotating diaphragm will be opened gradually in sequence, the heat load will be gradually reduced, and after the rotating diaphragm is fully opened, the external steam supply pipeline valve will be closed, and the unit will switch to pure condensing mode operation.

[0064] Example 3

[0065] An environmental protection power plant unit requires 40,000 kg / h of steam to be supplied externally, with a steam pressure of 1.5 MPa and a temperature of 230°C. The structure of this invention is designed to meet the user's needs.

[0066] The specific implementation plan is as follows:

[0067] Adjust the flow area between the rotating window and the holding window and the next stage stationary blade to 296.3 cm². 2 The designed window area is 716.3 cm². 2 The window area is 2.42 times the flow area of ​​the next stage stationary blade; the rotating baffle has 14 windows, evenly distributed around the entire ring, to meet the adjustment performance; the rotating baffle plate is made of ZG15Cr1Mo1 material and the rotating ring is made of Q345R material. Through finite element analysis, the maximum local contact pressure between the plate and the rotating ring window is calculated to be about 70MPa, and the average contact pressure is about 30MPa. The seal is good, and the mating surface will not undergo plastic deformation.

[0068] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A steam turbine throttling extraction steam regulation system, characterized in that: It includes a rotating partition, a connecting rod (5), an extraction chamber (6), a mixing chamber (7), a cylinder (8), and a hydraulic motor (9); the rotating partition includes a holding ring (1), a rotating ring (2), a cover ring (3), a holding ring window (4), and a rotating ring window (10); The holding ring (1) is a circular ring structure. The holding ring (1) is provided with a holding ring window (4). The holding ring (1) and the holding ring window (4) are integrally formed. The holding ring window (4) is evenly distributed around the central axis of the holding ring (1). The ring of the holding ring (1) with the holding ring window (4) is convex. The rotating ring (2) is a circular ring structure. The rotating ring (2) is provided with a rotating ring window (10). The rotating ring window (10) is evenly distributed around the central axis of the rotating ring (2). The rotating ring (2) is provided with a protrusion with a hole. The holding window (4) and the rotating window (10) are the same size; the number of holding windows (4) and the rotating window (10) are the same; The cover ring (3) has an arc-shaped segmented structure. The cover ring (3) is bolted to the holding ring (1) to fix the rotating ring (2) between the holding ring (1) and the cover ring (3). The connecting rod (5) is disposed between the rotating ring (2) and the hydraulic motor (9), and the rotating ring (2) and the hydraulic motor (9) are connected by a perforated protrusion on the rotating ring (2). The total area of ​​the holding window (4) is 2 to 2.5 times the flow area of ​​the next stage stationary blade; The height of the holding window (4) is 1.1 to 1.5 times the height of the next level stationary blade; The holding window (4) and the rotating window (10) form a flow channel. The rotation angle of the rotating ring (2) can be adjusted to be fully open or fully closed. The holding window (4) and the rotating window (10) are in a one-to-one correspondence when fully open. When the holding window (4) and the rotating window (10) are fully closed, at least 1° of window area is retained. The extraction chamber (6) is located in front of the rotating window (10); the mixing chamber (7) is located between the holding window (4) and the stationary blade; the ratio of the cross-sectional area of ​​the mixing chamber (7) to the annular area of ​​the next stage stationary blade inlet is greater than 0.2; the stationary blade is installed in the cylinder (8) through the holding ring (1) and together with the rotor impeller, forms the turbine flow channel.

2. The steam turbine throttling extraction regulating system according to claim 1, characterized in that: The retaining ring (1) consists of two parts, upper and lower, which are connected by bolts.

3. The steam turbine throttling extraction regulating system according to claim 1, characterized in that: The number of ring-holding windows (4) is 12 to 16.

4. The steam turbine throttling and extraction regulating system according to claim 1, characterized in that: The contact area between the holding ring (1) and the rotating ring (2) is under working conditions with stress lower than the allowable stress of the material, and the gap between the holding ring (1) and the rotating ring (2) is 0.4mm~0.6mm; The contact surface between the holding ring (1) and the rotating ring (2) is strengthened by nitriding; the gap between the rotating ring (2) and the cover ring (3) is 0.4mm~0.6mm.

5. A method for operating a steam turbine throttling extraction regulating system as described in any one of claims 1-4, comprising the following steps: (1) During installation, first adjust the swivel and connecting rod to the fully open position, and connect the hydraulic motor to stabilize it in that position; (2) When the unit is started, the rotating window and the holding window are fully open. At this time, the window area meets the full flow capacity, and all the steam passes through the turbine to do work. (3) When the unit needs steam outside, it enters the steam supply mode, adjusts the oil motor stroke, controls the connecting rod to drive the rotating ring to rotate, and adjusts the window area between the rotating ring window and the holding ring window; with the adjustment of the window area, the throttling effect is achieved, and the pressure of the extraction chamber gradually increases. When the extraction steam pressure is higher than the pressure value in the extraction steam header of the heating network, the external steam supply pipeline valve is opened to connect the heat load and adjust the extraction point pressure to the required pressure. (4) When the operation of the steam supply mode is switched to the pure condensing mode, the rotating diaphragm will be opened gradually in sequence, the heat load will be gradually reduced, and after the rotating diaphragm is fully opened, the external steam supply pipeline valve will be closed, and the unit will switch to pure condensing mode operation.

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