Steam supply system for feed water pump turbine

Abstract

The present disclosure relates to a steam supply system of a feed water pump turbine, comprising a steam inlet collecting pipeline, a first steam supply pipeline, a first check valve, an auxiliary steam supply pipeline, an auxiliary steam check valve, a first electric control regulating valve, a first pressure sensor, a second pressure sensor and a controller. The first end of the steam inlet collecting pipeline is adapted to communicate with the steam inlet of the feed water pump turbine, the first end of the first steam supply pipeline is adapted to communicate with the main steam source of the thermal power plant, the second end of the first steam supply pipeline communicates with the second end of the steam inlet collecting pipeline, the first check valve is arranged on the first steam supply pipeline, the first end of the auxiliary steam supply pipeline is adapted to communicate with the auxiliary steam source of the thermal power plant, the second end of the auxiliary steam supply pipeline communicates with the second end of the steam inlet collecting pipeline, the auxiliary steam check valve is arranged on the auxiliary steam supply pipeline, the first electric control regulating valve is arranged on the auxiliary steam supply pipeline, and the controller is electrically connected with the first electric control regulating valve, the first pressure sensor and the second pressure sensor.

Description

Technical Field

[0001] This disclosure relates to the field of feedwater pump turbine technology, and more specifically, to a steam supply system for a feedwater pump turbine. Background Technology

[0002] In recent years, with the vigorous development of new energy sources such as wind, solar, and nuclear power, the proportion of new energy in the power structure of various provinces has increased dramatically. In addition, the rapid growth of electricity from other provinces has seriously squeezed out the power of thermal power plants under unified dispatch within the province, resulting in the need for frequent adjustment of the operating load of thermal power generating units. When thermal power generating units are operating at low load, a large amount of steam will be surplus. In order to reduce the waste of steam, most thermal power generating units in China have been modified to enable them to supply steam to other industries.

[0003] In related technologies, thermal power generating units typically have a main steam turbine (such as the N1000-28 / 600 / 620 type 1000MW ultra-supercritical condensing steam turbine) and a feedwater pump turbine (such as the SD(Z)91 / 84 / 10 type 41MW variable-speed condensing steam turbine driving the feedwater pump). The steam driving the feedwater pump turbine is taken from the main steam turbine. Because the steam supplied to other industries diverts the steam driving the thermal power generating unit, when the operating load of the thermal power generating unit increases, the steam consumption of the main steam turbine increases, leading to a decrease in the steam supplied to the feedwater pump turbine. This causes the feedwater pump turbine to malfunction, ultimately resulting in the shutdown of the thermal power generating unit. Summary of the Invention

[0004] The purpose of this disclosure is to provide a steam supply system for a feedwater pump turbine that can supply sufficient steam to the feedwater pump turbine when the operating load of a thermal power generating unit increases, thereby ensuring the normal operation of the feedwater pump turbine.

[0005] To achieve the above objectives, this disclosure provides a steam supply system for a feedwater pump turbine, comprising:

[0006] A steam inlet manifold, the first end of which is adapted to be connected to the steam inlet of the feedwater pump turbine;

[0007] The first steam supply pipeline has a first end adapted to be connected to the main steam source of the thermal power plant, and the second end of the first steam supply pipeline is connected to the second end of the steam inlet concentrator pipeline.

[0008] The first check valve is installed on the first steam supply pipeline;

[0009] An auxiliary steam supply pipeline, wherein the first end of the auxiliary steam supply pipeline is adapted to be connected to the auxiliary steam source of the thermal power plant, and the second end of the auxiliary steam supply pipeline is connected to the second end of the steam inlet collection pipeline;

[0010] Auxiliary steam check valve is installed on the auxiliary steam supply pipeline;

[0011] The first electrically controlled regulating valve is installed on the auxiliary steam supply pipeline;

[0012] The first pressure sensor is used to detect the pressure value P1 inside the steam inlet manifold;

[0013] The second pressure sensor is used to detect the pressure value P2 between the regulating stage of the feedwater pump turbine and the first stage blades of the feedwater pump turbine.

[0014] The controller is electrically connected to the first electronically controlled regulating valve, the first pressure sensor, and the second pressure sensor.

[0015] When P1 < S1 * P2, the controller controls the first electrically controlled regulating valve to gradually increase its opening, where S1 ≥ 1;

[0016] When P1 > S1*S2*P2, the controller controls the first electronically controlled regulating valve to gradually reduce its opening, where S2 > 1.

[0017] Optionally, the steam supply system of the feedwater pump turbine further includes:

[0018] The second steam supply pipeline has a first end adapted to be connected to the cold re-extraction steam source of the thermal power plant, and a second end connected to the second end of the steam inlet collection pipeline.

[0019] The second check valve is installed on the second steam supply pipeline;

[0020] The second electrically controlled regulating valve is installed on the second steam supply pipeline and is electrically connected to the controller.

[0021] When P1 < N1 * P2, the controller controls the second electronically controlled regulating valve to gradually increase its opening, where S1 > N1;

[0022] When P1 > N1*N2*P2, the controller controls the second electronically controlled regulating valve to gradually reduce its opening, where N2 > 1.

[0023] Optionally, the first electrically controlled regulating valve is configured to open or close at 0.2% to 0.4% of its maximum opening per second, and the opening adjustment range of the first electrically controlled regulating valve is set to 0% to 80% of its maximum opening; and / or,

[0024] The second electrically controlled regulating valve is set to open or close at 0.2% to 0.4% of its maximum opening per second, and the opening adjustment range of the second electrically controlled regulating valve is set to 0% to 80% of its maximum opening.

[0025] Optionally, S1 is set to 1.5 to 1.7; and / or,

[0026] The value of N1 is set to 1.3 to 1.45.

[0027] Optionally, S2 is set to 1.03 to 1.08; and / or,

[0028] The N2 is set to 1.03 to 1.08.

[0029] Optionally, the steam supply system of the feedwater pump turbine further includes an inlet steam switch valve, which is installed on the inlet steam collection pipeline;

[0030] When P1 ≤ 0.4 MPa, the controller controls the first electrically controlled regulating valve to gradually increase its opening.

[0031] Optionally, the steam supply system of the feedwater pump turbine further includes a first switching valve and a second switching valve;

[0032] The first switching valve is installed on the auxiliary steam supply pipeline and is located upstream of the first electrically controlled regulating valve;

[0033] The second switching valve is installed on the auxiliary steam supply pipeline and is located downstream of the first electrically controlled regulating valve.

[0034] Optionally, the steam supply system of the feedwater pump turbine also includes an auxiliary steam header and a third pressure sensor;

[0035] The auxiliary steam header is provided with a header steam inlet and a header steam outlet. The header steam inlet is adapted to be connected to the auxiliary steam source, and the header steam outlet is connected to the first end of the auxiliary steam supply pipeline.

[0036] The third pressure sensor is used to detect the pressure value P3 inside the auxiliary steam header;

[0037] When P1 < S1*P2 < P3, the controller controls the first electrically controlled regulating valve to gradually increase its opening.

[0038] When S1*S2*P2>P3, the controller controls the first electrically controlled regulating valve to gradually reduce its opening.

[0039] Optionally, the steam supply system of the feedwater pump turbine further includes a connecting pipe and a third electrically controlled regulating valve;

[0040] The first end of the connecting pipe is adapted to be connected to the cold re-extraction steam source of the thermal power plant, the second end of the connecting pipe is connected to the steam inlet of the header, and the third electrically controlled regulating valve is installed on the connecting pipe and electrically connected to the controller.

[0041] The main steam turbine of the thermal power plant has a maximum power generation load C0 and a current power generation load C1;

[0042] When C1≤0.8*C0 and P3<0.8MPa, the controller controls the third electrically controlled regulating valve to gradually increase its opening.

[0043] When C1≤0.8*C0 and P3>0.8MPa, the controller controls the third electrically controlled regulating valve to gradually reduce its opening.

[0044] When 0.8*C0<C1≤0.9*C0 and P3<0.95MPa, the controller controls the third electrically controlled regulating valve to gradually increase its opening.

[0045] When 0.8*C0<C1≤0.9*C0 and P3>0.95MPa, the controller controls the third electrically controlled regulating valve to gradually reduce its opening.

[0046] When 0.9*C0<C1≤1.0*C0 and P3<1.1MPa, the controller controls the third electrically controlled regulating valve to gradually increase its opening.

[0047] When 0.9*C0<C1≤1.0*C0 and P3>1.1MPa, the controller controls the third electrically controlled regulating valve to gradually reduce its opening.

[0048] Optionally, the steam supply system of the feedwater pump turbine further includes multiple automatic regulating valves connected in parallel. The inlet of each automatic regulating valve is connected to the first end of the steam inlet concentrator, the outlet of each automatic regulating valve is connected to the steam inlet of the feedwater pump turbine, and each automatic regulating valve is electrically connected to the controller.

[0049] The upper limit of the opening of each of the automatic regulating valves is set to 75% to 85% of its maximum opening.

[0050] Through the above technical solution, since the first end of the first steam supply pipeline is connected to the main steam source of the thermal power plant, and the second end of the first steam supply pipeline is connected to the second end of the steam inlet concentrator pipeline, and the first end of the steam inlet concentrator pipeline is used to connect to the steam inlet of the feedwater pump turbine, the feedwater pump turbine can obtain steam from the main steam source. Since the first end of the auxiliary steam supply pipeline can be connected to the auxiliary steam source of the thermal power plant, and the second end of the auxiliary steam supply pipeline is connected to the second end of the steam inlet concentrator pipeline, the feedwater pump turbine can also obtain steam from the auxiliary steam source. This increases the number of steam sources supplying steam to the feedwater pump turbine, thereby enabling the thermal power generating unit to ensure the normal operation of the feedwater pump turbine when operating at higher loads.

[0051] Furthermore, since the auxiliary steam supply pipeline is equipped with a first electrically controlled regulating valve, and the first pressure sensor can detect the pressure value P1 inside the steam inlet manifold, and the second pressure sensor can detect the pressure value P2 between the regulating stage of the feedwater pump turbine and the first stage blade of the feedwater pump turbine (the pressure at this point is the pressure when the steam is about to do work on the feedwater pump turbine), the operator can set a value greater than or equal to 1 for S1 based on the pressure loss of steam flowing from the steam inlet manifold to the regulating stage of the feedwater pump turbine and the first stage blade of the feedwater pump turbine. When the pressure between the regulating stage of the feedwater pump turbine and the first stage blade of the feedwater pump turbine is P2, the pressure P1 in the steam inlet manifold should not be less than S1*P2. Therefore, when P1 < S1*P2, it means that the current steam supply from the main steam source and auxiliary steam source to the feedwater pump turbine is insufficient. In this case, the controller can gradually increase the opening of the first electrically controlled regulating valve, thereby increasing the steam supply from the auxiliary steam source to the feedwater pump turbine and meeting the steam supply requirements for the normal operation of the feedwater pump turbine. Therefore, the steam supply system for the feedwater pump turbine provided in this application can supply sufficient steam to the feedwater pump turbine when the operating load of the thermal power generating unit increases, ensuring the normal operation of the feedwater pump turbine.

[0052] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0053] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0054] Figure 1 This is a schematic diagram of the steam supply system of a feedwater pump turbine provided in one embodiment of the present disclosure.

[0055] Explanation of reference numerals in the attached figures

[0056] 1-Feedwater pump turbine; 2-Main steam source; 3-Auxiliary steam source; 4-Cold re-extraction steam source; 10-Inlet steam collection pipeline; 11-Inlet steam switch valve; 12-Automatic regulating valve; 20-First steam supply pipeline; 21-First check valve; 30-Auxiliary steam supply pipeline; 31-Auxiliary steam check valve; 32-First electrically controlled regulating valve; 33-First switch valve; 34-Second switch valve; 41-First pressure sensor; 42-Second pressure sensor; 43-Third pressure sensor; 50-Second steam supply pipeline; 51-Second check valve; 52-Second electrically controlled regulating valve; 60-Auxiliary steam header; 61-Header steam inlet; 62-Header steam outlet; 70-Connecting pipe; 71-Third electrically controlled regulating valve. Detailed Implementation

[0057] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0058] In this disclosure, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally defined with respect to the orientation of the corresponding drawings and are used only for the convenience of describing this disclosure and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or a specific orientation construction and operation, and therefore should not be construed as a limitation of this disclosure. "Inner" and "outer" refer to the inside and outside of the outline of the corresponding component. In addition, the terms "first," "second," etc., are used to distinguish one element from another and do not have sequentiality or importance.

[0059] In the description of this disclosure, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "connect," "link," and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances. Furthermore, in the description of this disclosure, "*" represents a multiplication sign, such as S1*P2 representing the product of S1 and P2.

[0060] like Figure 1As shown, this disclosure provides a steam supply system for a feedwater pump turbine 1, including a steam inlet manifold 10, a first steam supply pipeline 20, a first check valve 21, an auxiliary steam supply pipeline 30, an auxiliary steam check valve 31, a first electrically controlled regulating valve 32, a first pressure sensor 41, a second pressure sensor 42, and a controller. The first end of the steam inlet manifold 10 is adapted to be connected to the steam inlet of the feedwater pump turbine 1. The first end of the first steam supply 20 is adapted to be connected to the main steam source 2 of the thermal power plant. The second end of the first steam supply 20 is connected to the second end of the steam inlet manifold 10. The first check valve 21 is installed on the first steam supply 20. The first end of the auxiliary steam supply 30 is adapted to be connected to the auxiliary steam source 3 of the thermal power plant. The second end of the auxiliary steam supply 30 is connected to the second end of the steam inlet manifold 10. The auxiliary steam check valve 31 is installed on the auxiliary steam supply 30. The first electrically controlled regulating valve 32 is installed on the auxiliary steam supply 30. The first pressure sensor 41 is used to detect the pressure value P1 inside the steam inlet manifold 10. The second pressure sensor 42 is used to detect the pressure value P2 between the regulating stage of the feedwater pump turbine 1 and the first stage blade of the feedwater pump turbine 1. The controller is electrically connected to the first electrically controlled regulating valve 32, the first pressure sensor 41, and the second pressure sensor 42. When P1 < S1*P2, the controller controls the first electrically controlled regulating valve 32 to gradually increase its opening, where S1 ≥ 1. When P1 > S1*S2*P2, the controller controls the first electrically controlled regulating valve 32 to gradually decrease its opening, where S2 > 1.

[0061] Through the above technical solution, since the first end of the first steam supply pipeline 20 is connected to the main steam source 2 of the thermal power plant, and the second end of the first steam supply pipeline 20 is connected to the second end of the steam inlet collection pipeline 10, and the first end of the steam inlet collection pipeline 10 is used to connect to the steam inlet of the feedwater pump turbine 1, the feedwater pump turbine 1 can obtain steam from the main steam source 2. Since the first end of the auxiliary steam supply pipeline 30 can be connected to the auxiliary steam source 3 of the thermal power plant, and the second end of the auxiliary steam supply pipeline 30 is connected to the second end of the steam inlet collection pipeline 10, the feedwater pump turbine 1 can also obtain steam from the auxiliary steam source 3. This increases the number of steam sources supplying steam to the feedwater pump turbine 1, thereby enabling the thermal power generating unit to ensure the normal operation of the feedwater pump turbine 1 when operating at higher loads.

[0062] Furthermore, since the auxiliary steam supply pipeline 30 is equipped with a first electrically controlled regulating valve 32, and the first pressure sensor 41 can detect the pressure value P1 inside the steam inlet manifold 10, and the second pressure sensor 42 can detect the pressure value P2 between the regulating stage of the feedwater pump turbine 1 and the first stage blade of the feedwater pump turbine 1 (the pressure at this point is the pressure when the steam is about to do work on the feedwater pump turbine 1), the operator can set a value greater than or equal to 1 for S1 based on the pressure loss of steam flowing from the steam inlet manifold 10 to the regulating stage of the feedwater pump turbine 1 and the first stage blade of the feedwater pump turbine 1. When the pressure between the regulating stage of the feedwater pump turbine 1 and the first stage blade of the feedwater pump turbine 1 is P2, the pressure P1 of the steam inlet manifold 10 should not be less than S1*P2. Therefore, when P1 < S1*P2, it means that the steam supplied to the feedwater pump turbine 1 by the main steam source 2 and the auxiliary steam source 3 is insufficient. At this time, the opening of the first electrically controlled regulating valve 32 can be gradually increased by the controller, so that the steam supplied to the feedwater pump turbine 1 by the auxiliary steam source 3 increases, thereby meeting the steam supply required for the normal operation of the feedwater pump turbine 1. Therefore, the steam supply system for the feedwater pump turbine 1 provided in this application can supply sufficient steam to the feedwater pump turbine 1 when the operating load of the thermal power generating unit increases, ensuring the normal operation of the feedwater pump turbine 1.

[0063] To prevent the auxiliary steam source 3 from supplying steam to the feedwater pump turbine 1 beyond the upper limit of steam required for the normal operation of the feedwater pump turbine 1, thus wasting steam, and to prevent the first electrically controlled regulating valve 32 from frequently operating, the designer can set an S2 value greater than 1. When P1 > S1*S2*P2, it means that the current auxiliary steam source 3 is supplying too much steam to the feedwater pump turbine 1. At this time, the controller can control the first electrically controlled regulating valve 32 to gradually reduce its opening, thereby reducing the amount of steam supplied by the auxiliary steam source 3 to the feedwater pump turbine 1, thus reducing steam waste and preventing the first electrically controlled regulating valve 32 from frequently operating, which is beneficial to reducing the wear and tear on the life of the first electrically controlled regulating valve 32.

[0064] Furthermore, when the steam pressure of the auxiliary steam source 3 is greater than the steam pressure of the main steam source 2, the first check valve 21 installed on the first steam supply line 20 can prevent the steam from the auxiliary steam supply line 30 from affecting the main steam source 2. Similarly, when the steam pressure of the auxiliary steam source 3 is less than the steam pressure of the main steam source 2, the auxiliary steam check valve 31 installed on the auxiliary steam supply line 30 can prevent the steam from the first steam supply line 20 from affecting the auxiliary steam source 3.

[0065] Optionally, the main steam turbine can be a 1000MW ultra-supercritical condensing steam turbine of type N1000-28 / 600 / 620, and the main steam source 2 can be a four-stage extraction steam source. The extraction point of the four-stage extraction steam source can be after the 8th stage blade of the intermediate pressure cylinder of the main steam turbine.

[0066] Optionally, the auxiliary steam source 3 may include steam extracted from the thermal power generating unit, or it may include other steam sources in the thermal power plant besides the thermal power generating unit. This disclosure does not limit this.

[0067] like Figure 1 As shown, the steam supply system of the feedwater pump turbine 1 may also include a second steam supply pipeline 50, a second check valve 51, and a second electrically controlled regulating valve 52. The first end of the second steam supply pipeline 50 is adapted to connect to the cold re-extraction steam source 4 of the thermal power plant, and the second end of the second steam supply pipeline 50 is connected to the second end of the steam inlet collection pipeline 10. The second check valve 51 is installed on the second steam supply pipeline 50, and the second electrically controlled regulating valve 52 is installed on the second steam supply pipeline 50 and electrically connected to the controller. When P1 < N1*P2, the controller controls the second electrically controlled regulating valve 52 to gradually increase its opening. To ensure that the cold re-extraction steam source 4 and the auxiliary steam source 3 can supply steam to the feedwater pump turbine 1 at different P1 values, the operator can set N1 to a value less than S1 according to actual needs. When P1 > N1*N2*P2, the controller controls the second electrically controlled regulating valve 52 to gradually decrease its opening, where N2 > 1.

[0068] Since the first end of the second steam supply pipeline 50 is connected to the cold re-extraction steam source 4 of the thermal power plant, and the second end of the second steam supply pipeline 50 is connected to the second end of the steam inlet collection pipeline 10, the feedwater pump turbine 1 can also obtain steam through the cold re-extraction steam source 4, thereby increasing the number of steam sources supplying steam to the feedwater pump turbine 1, and thus enabling the thermal power generating unit to ensure the normal operation of the feedwater pump turbine 1 when operating at higher loads.

[0069] Furthermore, since a second electrically controlled regulating valve 52 is installed on the second steam supply pipeline 50, and S1 > N1, when P1 < N1*P2, it means that the current main steam source 2 and auxiliary steam source 3 are not supplying enough steam to the feedwater pump turbine 1. At this time, the controller can control the second electrically controlled regulating valve 52 to gradually increase the opening, so that the steam supplied by the cold re-extraction steam source 4 to the feedwater pump turbine 1 increases, thereby meeting the steam supply required for the normal operation of the feedwater pump turbine 1.

[0070] To prevent the steam supplied by the cold re-extraction steam source 4 to the feedwater pump turbine 1 from exceeding the upper limit of steam required for the normal operation of the feedwater pump turbine 1, thus wasting steam, and to prevent the second electrically controlled regulating valve 52 from frequently operating, the designer can set N2 to a value greater than 1. When P1 > N1*N2*P2, it means that the current steam supplied by the cold re-extraction steam source 4 to the feedwater pump turbine 1 is too much. At this time, the controller can control the first electrically controlled regulating valve 32 to gradually reduce the opening, thereby reducing the steam supplied by the cold re-extraction steam source 4 to the feedwater pump turbine 1, thus reducing steam waste and preventing the second electrically controlled regulating valve 52 from frequently operating, which is beneficial to reducing the wear and tear on the life of the second electrically controlled regulating valve 52.

[0071] In addition, the second check valve 51 installed on the second steam supply line 50 can prevent the steam from the auxiliary steam supply line 30 and the steam from the first steam supply line 20 from affecting the cold re-extraction steam source 4.

[0072] Optionally, the extraction point of the cold re-extraction steam source 4 can be between the high-pressure exhaust port of the main steam turbine and the boiler reheater of the thermal power generating unit.

[0073] To make the steam supplied by the auxiliary steam source 3 to the feedwater pump turbine 1 more stable, the first electrically controlled regulating valve 32 can optionally be set to open or close at 0.2% to 0.4% of its maximum opening per second, which helps to reduce the impact of steam pressure changes on the feedwater pump turbine 1. The opening adjustment range of the first electrically controlled regulating valve 32 can be set to 0% to 80% of its maximum opening, so that the first electrically controlled regulating valve 32 can more sensitively control the steam supplied by the auxiliary steam source 3 to the feedwater pump turbine 1.

[0074] To make the steam supplied from the cold re-extraction steam source 4 to the feedwater pump turbine 1 more stable, the second electrically controlled regulating valve 52 can optionally be set to open or close at 0.2% to 0.4% of its maximum opening per second. This helps to reduce the impact of steam pressure changes on the feedwater pump turbine 1. The opening adjustment range of the second electrically controlled regulating valve 52 can be set to 0% to 80% of its maximum opening, so that the second electrically controlled regulating valve 52 can more sensitively control the steam supplied from the cold re-extraction steam source 4 to the feedwater pump turbine 1.

[0075] Staff can set S1 to any suitable value according to the actual situation. This disclosure does not limit this value. Optionally, S1 can be set to 1.5 to 1.7. Preferably, S1 can be set to 1.6.

[0076] In order to enable the cold re-extraction steam source 4 and the auxiliary steam source 3 to supply sufficient steam to the feedwater pump turbine 1 under different P1 values, N1 can optionally be set to 1.3 to 1.45, and preferably, N1 can be set to 1.4.

[0077] Staff can set S2 to any suitable value according to actual needs. This disclosure does not limit this value. Optionally, S2 can be set to 1.03 to 1.08. Preferably, S2 can be set to 1.05.

[0078] In addition, N2 can be set to any suitable value. Optionally, N2 can be set to 1.03 to 1.08, and preferably, N2 can be set to 1.05.

[0079] Starting the water pump turbine 1 requires supplying steam at a preset pressure (the preset pressure may differ from the steam pressure required for normal operation of the water pump turbine 1). However, when the thermal power generator unit is shut down, the main steam source 2 cannot supply steam to the water pump turbine 1. To facilitate starting the water pump turbine 1, as one implementation method is... Figure 1 As shown, the steam supply system of the feedwater pump turbine 1 also includes a steam inlet switch valve 11. The steam inlet switch valve 11 is installed on the steam inlet manifold 10. When P1≤0.4MPa, the controller controls the first electrically controlled regulating valve 32 to gradually increase the opening.

[0080] When the water pump turbine 1 is started, the controller can activate the control logic of the first electrically controlled valve "when P1≤0.4MPa, the controller controls the first electrically controlled regulating valve 32 to gradually increase the opening" and deactivate the controller's control logic of the first electrically controlled valve and / or the second electrically controlled valve except for "when P1≤0.4MPa, the controller controls the first electrically controlled regulating valve 32 to gradually increase the opening". Then, the steam inlet switch valve 11 is opened, so that the auxiliary steam source 3 stably supplies steam at a preset pressure to the water pump turbine 1, which facilitates and speeds up the start-up of the water pump turbine 1.

[0081] To facilitate the maintenance of the first electrically controlled regulating valve 32, as one implementation method, such as Figure 1 As shown, the steam supply system of the feedwater pump turbine 1 also includes a first switching valve 33 and a second switching valve 34. The first switching valve 33 is installed on the auxiliary steam supply pipeline 30 and is located upstream of the first electrically controlled regulating valve 32. The second switching valve 34 is installed on the auxiliary steam supply pipeline 30 and is located downstream of the first electrically controlled regulating valve 32.

[0082] When the first electrically controlled valve needs to be repaired, the first switching valve 33 and the second switching valve 34 can be closed to block the flow of steam to the first electrically controlled regulating valve 32, thereby facilitating the maintenance or replacement of the first electrically controlled regulating valve 32 by the staff.

[0083] It should be noted that the upstream and downstream of the auxiliary steam supply pipeline 30 are defined by the direction of steam flow within the auxiliary steam supply pipeline 30.

[0084] To ensure a more stable steam supply from the auxiliary steam supply pipeline 30 to the feedwater pump turbine 1, as one implementation method, such as... Figure 1 As shown, the steam supply system of the feedwater pump turbine 1 may also include an auxiliary steam header 60 and a third pressure sensor 43. The auxiliary steam header 60 is provided with a header inlet 61 and a header outlet 62. The header inlet 61 is adapted to be connected to the auxiliary steam source 3, and the header outlet 62 is connected to the first end of the auxiliary steam supply pipeline 30. The third pressure sensor 43 is used to detect the pressure value P3 inside the auxiliary steam header 60. When P1 < S1*P2 < P3, the controller controls the first electrically controlled regulating valve 32 to gradually increase its opening. When S1*S2*P2 > P3, the controller controls the first electrically controlled regulating valve 32 to gradually decrease its opening.

[0085] Since the header inlet 61 can be connected to the auxiliary steam source 3, and the header outlet 62 is connected to the first end of the auxiliary steam supply pipeline 30, the steam from the auxiliary steam source 3 can be stabilized inside the auxiliary steam header 60 before being delivered to the water pump turbine 1, thereby making the steam supplied by the auxiliary steam supply pipeline 30 to the feedwater pump turbine 1 more stable.

[0086] Furthermore, when P1 < S1*P2 < P3, meaning the steam pressure P3 in the auxiliary steam header 60 is greater than the target pressure S1*P2 inside the steam inlet manifold 10, the controller can control the first electrically controlled regulating valve 32 to gradually increase its opening. Conversely, when S1*S2*P2 > P3, meaning the steam pressure P3 in the auxiliary steam header 60 is less than the target pressure S1*P2 inside the steam inlet manifold 10, the controller can control the first electrically controlled regulating valve 32 to gradually decrease its opening. This effectively reduces the number of times the first electrically controlled regulating valve 32 operates when the auxiliary steam header 60 does not meet the conditions for supplying steam to the feedwater pump turbine 1, thereby extending the service life of the first electrically controlled regulating valve 32.

[0087] In this disclosure, optionally, such as Figure 1As shown, the steam supply system of the feedwater pump turbine 1 may also include a connecting pipe 70 and a third electrically controlled regulating valve 71. The first end of the connecting pipe 70 is adapted to be connected to the cold re-extraction steam source 4 of the thermal power plant, and the second end of the connecting pipe 70 is connected to the header steam inlet 61. The third electrically controlled regulating valve 71 is installed on the connecting pipe 70 and electrically connected to the controller. The main steam turbine of the thermal power plant has a maximum power generation load C0 and a current power generation load C1. When C1≤0.8*C0 and P3<0.8MPa, the controller controls the third electrically controlled regulating valve 71 to gradually increase the opening. When C1≤0.8*C0 and P3>0.8MPa, the controller controls the third electrically controlled regulating valve 71 to gradually increase the opening. The control valve 71 gradually decreases its opening. When 0.8*C0 < C1 ≤ 0.9*C0 and P3 < 0.95MPa, the controller controls the third electrically controlled control valve 71 to gradually increase its opening. When 0.8*C0 < C1 ≤ 0.9*C0 and P3 > 0.95MPa, the controller controls the third electrically controlled control valve 71 to gradually decrease its opening. When 0.9*C0 < C1 ≤ 1.0*C0 and P3 < 1.1MPa, the controller controls the third electrically controlled control valve 71 to gradually increase its opening. When 0.9*C0 < C1 ≤ 1.0*C0 and P3 > 1.1MPa, the controller controls the third electrically controlled control valve 71 to gradually decrease its opening.

[0088] Since the first end of the connecting pipe 70 can be connected to the cold re-extraction steam source 4 and the second end of the connecting pipe 70 can be connected to the steam inlet 61 of the header, the steam from the cold re-extraction steam source can be supplemented into the auxiliary steam header 60, thereby reducing the situation where the auxiliary steam header 60 is not sufficient to supply steam to the feedwater pump turbine 1.

[0089] Furthermore, through the third electrically controlled regulating valve 71 installed on the connecting pipe 70, the steam pressure in the auxiliary steam header 60 can be replenished to different values ​​under different power generation loads of the main steam turbine via the cold re-extraction steam source 4. That is, when C1≤0.8*C0, the cold re-extraction steam source 4 can replenish the steam pressure in the auxiliary steam header 60 to 0.8MPa; when 0.8*C0<C1≤0.9*C0, the cold re-extraction steam source 4 can replenish the steam pressure in the auxiliary steam header 60 to 0.95MPa; and when 0.9*C0<C1≤1.0*C0, the cold re-extraction steam source 4 can replenish the steam pressure in the auxiliary steam header 60 to 1.1MPa. This allows the auxiliary steam header 60 to supply steam to the feedwater pump turbine 1 under different power generation loads of the main steam turbine.

[0090] To improve the operational stability of the feedwater pump turbine 1, as one embodiment of this disclosure, such as... Figure 1As shown, the steam supply system of the feedwater pump turbine 1 may also include multiple automatic regulating valves 12 connected in parallel. The inlet of each automatic regulating valve 12 is connected to the first end of the steam inlet manifold 10, and the outlet of each automatic regulating valve 12 is connected to the steam inlet of the feedwater pump turbine 1. Each automatic regulating valve 12 is electrically connected to the controller. The upper limit of the opening of each automatic regulating valve 12 is set to 75% to 85% of its maximum opening.

[0091] Operators can set the control logic of multiple automatic regulating valves 12 appropriately to ensure that the steam pressure delivered from the steam inlet manifold 10 to the feedwater pump turbine 1 is stable within a suitable range, thereby improving the operational stability of the feedwater pump turbine 1.

[0092] In addition, the upper limit of the opening of each automatic regulating valve 12 is set to 75% to 85% of its own maximum opening, which can improve the regulating sensitivity of the automatic regulating valve 12 and also avoid the impact of vibration generated when the automatic regulating valve 12 is fully open on the surrounding pipelines and valves.

[0093] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0094] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0095] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A steam supply system for a feedwater pump turbine, characterized in that, include: A steam inlet manifold, the first end of which is adapted to be connected to the steam inlet of the feedwater pump turbine; The first steam supply pipeline has a first end adapted to be connected to the main steam source of the thermal power plant, and the second end of the first steam supply pipeline is connected to the second end of the steam inlet concentrator pipeline. The first check valve is installed on the first steam supply pipeline; An auxiliary steam supply pipeline, wherein the first end of the auxiliary steam supply pipeline is adapted to be connected to the auxiliary steam source of the thermal power plant, and the second end of the auxiliary steam supply pipeline is connected to the second end of the steam inlet collection pipeline; Auxiliary steam check valve is installed on the auxiliary steam supply pipeline; The first electrically controlled regulating valve is installed on the auxiliary steam supply pipeline; The first pressure sensor is used to detect the pressure value P1 inside the steam inlet manifold; The second pressure sensor is used to detect the pressure value P2 between the regulating stage of the feedwater pump turbine and the first stage blades of the feedwater pump turbine. The controller is electrically connected to the first electronically controlled regulating valve, the first pressure sensor, and the second pressure sensor. When P1 < S1 * P2, the controller controls the first electrically controlled regulating valve to gradually increase its opening, where S1 ≥ 1; When P1 > S1*S2*P2, the controller controls the first electronically controlled regulating valve to gradually reduce its opening, where S2 > 1.

2. The steam supply system for the feedwater pump turbine according to claim 1, characterized in that, The steam supply system of the feedwater pump turbine also includes: The second steam supply pipeline has a first end adapted to be connected to the cold re-extraction steam source of the thermal power plant, and a second end connected to the second end of the steam inlet collection pipeline. The second check valve is installed on the second steam supply pipeline; The second electrically controlled regulating valve is installed on the second steam supply pipeline and is electrically connected to the controller. When P1 < N1 * P2, the controller controls the second electronically controlled regulating valve to gradually increase its opening, where S1 > N1; When P1 > N1*N2*P2, the controller controls the second electronically controlled regulating valve to gradually reduce its opening, where N2 > 1.

3. The steam supply system for the feedwater pump turbine according to claim 2, characterized in that, The first electrically controlled regulating valve is configured to open or close at 0.2% to 0.4% of its maximum opening per second, and the opening adjustment range of the first electrically controlled regulating valve is set to 0% to 80% of its maximum opening; and / or, The second electrically controlled regulating valve is set to open or close at 0.2% to 0.4% of its maximum opening per second, and the opening adjustment range of the second electrically controlled regulating valve is set to 0% to 80% of its maximum opening.

4. The steam supply system for the feedwater pump turbine according to claim 2, characterized in that, The S1 is set to 1.5 to 1.7; and / or, The value of N1 is set to 1.3 to 1.

45.

5. The steam supply system for the feedwater pump turbine according to claim 2, characterized in that, The S2 is set to 1.03–1.08; and / or, The N2 is set to 1.03 to 1.

08.

6. The steam supply system for the feedwater pump turbine according to any one of claims 1-5, characterized in that, The steam supply system of the feedwater pump turbine also includes a steam inlet switch valve, which is installed on the steam inlet manifold. When P1 ≤ 0.4 MPa, the controller controls the first electrically controlled regulating valve to gradually increase its opening.

7. The steam supply system for the feedwater pump turbine according to any one of claims 1-5, characterized in that, The steam supply system of the feedwater pump turbine also includes a first switching valve and a second switching valve; The first switching valve is installed on the auxiliary steam supply pipeline and is located upstream of the first electrically controlled regulating valve; The second switching valve is installed on the auxiliary steam supply pipeline and is located downstream of the first electrically controlled regulating valve.

8. The steam supply system for the feedwater pump turbine according to any one of claims 1-5, characterized in that, The steam supply system of the feedwater pump turbine also includes an auxiliary steam header and a third pressure sensor; The auxiliary steam header is provided with a header steam inlet and a header steam outlet. The header steam inlet is adapted to be connected to the auxiliary steam source, and the header steam outlet is connected to the first end of the auxiliary steam supply pipeline. The third pressure sensor is used to detect the pressure value P3 inside the auxiliary steam header; When P1 < S1*P2 < P3, the controller controls the first electrically controlled regulating valve to gradually increase its opening. When S1*S2*P2>P3, the controller controls the first electrically controlled regulating valve to gradually reduce its opening.

9. The steam supply system for the feedwater pump turbine according to claim 8, characterized in that, The steam supply system of the feedwater pump turbine also includes a connecting pipe and a third electrically controlled regulating valve; The first end of the connecting pipe is adapted to be connected to the cold re-extraction steam source of the thermal power plant, the second end of the connecting pipe is connected to the steam inlet of the header, and the third electrically controlled regulating valve is installed on the connecting pipe and electrically connected to the controller. The main steam turbine of the thermal power plant has a maximum power generation load C0 and a current power generation load C1; When C1≤0.8*C0 and P3<0.8MPa, the controller controls the third electrically controlled regulating valve to gradually increase its opening. When C1≤0.8*C0 and P3>0.8MPa, the controller controls the third electrically controlled regulating valve to gradually reduce its opening. When 0.8*C0<C1≤0.9*C0 and P3<0.95MPa, the controller controls the third electrically controlled regulating valve to gradually increase its opening. When 0.8*C0<C1≤0.9*C0 and P3>0.95MPa, the controller controls the third electrically controlled regulating valve to gradually reduce its opening. When 0.9*C0<C1≤1.0*C0 and P3<1.1MPa, the controller controls the third electrically controlled regulating valve to gradually increase its opening. When 0.9*C0<C1≤1.0*C0 and P3>1.1MPa, the controller controls the third electrically controlled regulating valve to gradually reduce its opening.

10. The steam supply system for the feedwater pump turbine according to any one of claims 1-5, characterized in that, The steam supply system of the feedwater pump turbine also includes multiple automatic regulating valves connected in parallel. The inlet of each automatic regulating valve is connected to the first end of the steam inlet concentrator, the outlet of each automatic regulating valve is connected to the steam inlet of the feedwater pump turbine, and each automatic regulating valve is electrically connected to the controller. The upper limit of the opening of each of the automatic regulating valves is set to 75% to 85% of its maximum opening.

Images