Steam feed pump unit capable of exhausting steam quickly
By introducing a pneumatic shut-off valve and sensor detection system into the steam-driven feedwater pump system, steam in the deaerator is quickly discharged, solving the problem of steam backflow in the deaerator and ensuring the safe and stable operation of the generator set.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENHUA GUONENG ENERGY GRP
- Filing Date
- 2025-08-08
- Publication Date
- 2026-05-19
AI Technical Summary
When the generator set rapidly reduces load or the unit's RB (refrigerant booster) is activated, steam in the deaerator flows back to the steam source inlet of the small turbine, resulting in insufficient steam source to drive the steam-driven feedwater pump. This causes low feedwater flow, triggering boiler water cut-off protection or water hammer vibration in the small turbine, affecting the safe operation of the unit.
A system was designed that includes a steam-driven feedwater pump, a four-extraction steam supply header, an auxiliary steam header, a cold reheat steam supply header, a deaerator, and a controller. The system uses pneumatic shut-off valves and sensors to detect pressure and temperature, enabling rapid discharge of steam from the deaerator and preventing backflow of the working fluid.
It effectively prevents steam backflow in the deaerator, ensures normal operation of the unit, avoids abnormal shutdowns, and improves the safety and stability of the generator set.
Smart Images
Figure CN224260406U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of generator set technology, and in particular to a steam-driven feedwater pump unit that can quickly exhaust steam. Background Technology
[0002] Currently, most newly commissioned ultra-supercritical coal-fired power generating units in China use small steam turbines to drive their feedwater pumps. The small steam turbines are driven by high-temperature and high-pressure steam (the feedwater pump and the small steam turbine are collectively referred to as steam-driven feedwater pumps). The stable operation of the steam-driven feedwater pumps directly affects the safe operation of the generator units. The steam-driven feedwater pumps have high requirements for the high-temperature and high-pressure steam parameters of the driving steam source. The driving steam source for the steam-driven feedwater pumps is usually supplied by the fourth extraction steam and auxiliary steam. The fourth extraction steam and auxiliary steam also supply the working fluid (water) in the deaerator for thermal deoxygenation. Therefore, the deaerator is indirectly connected to the steam source pipe of the steam-driven feedwater pump. Under various circumstances, such as rapid load reduction of the generator set, activation of the generator's RB (Remote Control Unit) system, or load shedding due to power system issues, the pressure of the fourth extraction and auxiliary steam will drop rapidly, as will the pressure inside the deaerator. In this situation, the working fluid inside the deaerator will flash, and the saturated water, which was originally under high pressure, will rapidly boil due to the pressure drop, with some water evaporating into steam. Due to the heat storage capacity of the deaerator, the pressure drop inside it will lag, resulting in the pressure inside the deaerator being higher than the pressure of the fourth extraction. Therefore, this cold steam will flow back to the steam source inlet of the small turbine, causing insufficient power to drive the steam source of the steam-driven feedwater pump. This results in low feedwater flow, triggering the boiler water cut-off protection, or large water impact vibration and axial displacement of the small turbine, causing the steam-driven feedwater pump to trip protection, and low feedwater flow triggering the boiler water cut-off protection, ultimately leading to abnormal shutdown of the generator set.
[0003] Currently, the main method to prevent the working fluid in the deaerator from flowing back into the small steam turbine is to install a disc check valve on the steam supply pipeline connected to the deaerator. The disc check valve is a one-way valve. When the working fluid flows in the forward direction, it pushes open the valve disc, and when the working fluid flows in the reverse direction, it closes the valve disc, thus preventing backflow. However, the valve disc of the disc check valve is a thick metal plate. After the valve disc is closed, there will be a large gap at the joint surface, and high-pressure steam will flow through the gap. Moreover, during operation, the valve disc is in the high-temperature working fluid. The metal valve disc expands due to heat, which increases friction with the valve body. There is a jamming phenomenon when closing, resulting in poor backflow prevention effect of the disc check valve. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a steam-driven feedwater pump unit that can quickly discharge steam in the deaerator when flash evaporation occurs, so as to prevent backflow of the working fluid in the deaerator.
[0005] To solve the above-mentioned technical problems, this utility model provides a steam-driven feedwater pump unit capable of rapid steam exhaust, including a steam-driven feedwater pump, a four-extraction steam supply main pipe, an auxiliary steam header, a cold reheat steam supply main pipe, a deaerator, and a controller. The steam inlet of the steam-driven feedwater pump is connected to the steam inlet main pipe. The four-extraction steam supply main pipe is connected to the steam inlet main pipe, the first steam inlet of the deaerator, and the first steam inlet of the auxiliary steam header via four-extraction steam supply branch pipes. The cold reheat steam supply main pipe is connected to the steam inlet main pipe and the auxiliary steam header via cold reheat steam supply branch pipes. The second steam inlet of the auxiliary steam header is connected, the first steam supply port of the auxiliary steam header is connected to the main steam supply pipe through the first steam supply pipe, the second steam supply port of the auxiliary steam header is connected to the second steam inlet of the deaerator through the second steam supply pipe, the top of the deaerator is provided with a steam exhaust port, the steam exhaust port is connected to a main steam exhaust pipe, the main steam exhaust pipe is connected to multiple steam exhaust branch pipes, the steam exhaust branch pipes are provided with pneumatic shut-off valves, the multiple steam exhaust branch pipes are respectively connected to the steam exhaust outlet pipe, and the controller is electrically connected to the pneumatic shut-off valve.
[0006] As a preferred embodiment of this utility model, the unit further includes a first pressure sensor for detecting the pressure in the four-extraction steam supply header, a second pressure sensor for detecting the pressure in the deaerator, and a third pressure sensor for detecting the pressure in the steam inlet header. The first pressure sensor, the second pressure sensor, and the third pressure sensor are electrically connected to the controller.
[0007] As a preferred embodiment of this utility model, the unit further includes a first temperature sensor for detecting the temperature inside the steam inlet header, a second temperature sensor for detecting the temperature inside the four extraction steam supply header, a third temperature sensor for detecting the temperature inside the auxiliary steam header, and a fourth temperature sensor for detecting the temperature inside the cold reheat steam supply branch pipe connected to the steam inlet header. The first, second, third, and fourth temperature sensors are electrically connected to the controller.
[0008] As a preferred embodiment of this utility model, the first pressure sensor, the second pressure sensor, and the third pressure sensor are each provided with multiple detection points.
[0009] As a preferred embodiment of this utility model, the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor are each provided with multiple detection points.
[0010] As a preferred embodiment of this utility model, a manual shut-off valve is provided on the exhaust branch pipe.
[0011] As a preferred embodiment of this utility model, the exhaust branch pipe includes a first branch pipe, a second branch pipe, and a third branch pipe, wherein the diameter of the first branch pipe is larger than the diameter of the second branch pipe, and the diameter of the second branch pipe is larger than the diameter of the third branch pipe.
[0012] As a preferred embodiment of this utility model, the four-extraction steam supply branch pipe connected to the first steam inlet of the deaerator is provided with a first check valve and a first shut-off valve.
[0013] As a preferred embodiment of this utility model, the first steam supply pipe is provided with a second check valve and a second shut-off valve.
[0014] As a preferred embodiment of this utility model, the exhaust outlet pipe is connected to the hydrophobic expansion container.
[0015] This utility model provides a start-up feedwater pump unit capable of rapid steam venting. Compared with the prior art, its advantages are as follows: four extraction steam sources supply steam to the steam-driven feedwater pump, deaerator, and auxiliary steam header respectively through the four extraction steam supply header; a cold reheat steam source supplies steam to the steam-driven feedwater pump and auxiliary steam header respectively through the cold reheat steam supply header; and the auxiliary steam header supplies steam to the steam-driven feedwater pump and deaerator respectively. Under normal circumstances, the pneumatic shut-off valve is in the closed state. When the working fluid in the deaerator flashes, the controller controls the pneumatic shut-off valve to open, and the steam in the deaerator is discharged through the exhaust header and exhaust branch pipe, realizing rapid steam venting of the deaerator to reduce the pressure in the deaerator. This prevents the working fluid from flowing back due to the pressure in the deaerator exceeding the pressure of the four extraction steam sources and auxiliary steam header, ensuring the normal operation of the unit. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of this utility model;
[0017] Figure 2 This is a schematic diagram of the connection structure between the exhaust steam main pipe and the exhaust steam branch pipe of this utility model.
[0018] In the diagram, the following components are included: steam-driven feedwater pump 1; steam inlet main pipe 11; third pressure sensor 12; first temperature sensor 13; fourth extraction steam supply main pipe 2; fourth extraction steam supply branch pipe 21; first check valve 211; first shut-off valve 212; first pressure sensor 22; second temperature sensor 23; auxiliary steam header 3; first steam supply pipe 31; second steam supply pipe 32; second check valve 321; second shut-off valve 322; third temperature sensor 33; cold reheat steam supply main pipe 4; cold reheat steam supply branch pipe 41; fourth temperature sensor 42; deaerator 5; exhaust steam main pipe 51; exhaust steam branch pipe 52; first branch pipe 521; second branch pipe 522; third branch pipe 523; pneumatic shut-off valve 53; manual shut-off valve 54; exhaust steam outlet pipe 55; and second pressure sensor 56. Detailed Implementation
[0019] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.
[0020] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0021] like Figure 1 As shown in Figure 2, a preferred embodiment of this utility model of a steam-driven feedwater pump unit capable of rapid steam exhaust includes a steam-driven feedwater pump 1, a four-stage extraction steam supply main pipe 2, an auxiliary steam header 3, a cold reheat steam supply main pipe 4, a deaerator 5, and a controller (not shown in the figure). The steam inlet of the steam-driven feedwater pump 1 is connected to the steam inlet main pipe 11. The four-stage extraction (fourth stage extraction) steam source is connected to the steam inlet main pipe 11. The four-stage extraction steam supply main pipe 2 is connected to the steam inlet main pipe 11 through four-stage extraction steam supply branch pipes 21. Pipe 11, the first steam inlet of deaerator 5, and the first steam inlet of auxiliary steam header 3 are connected. Specifically, the four-extraction steam supply main pipe 2 is connected to three four-extraction steam supply branch pipes 21. The three four-extraction steam supply branch pipes 21 are connected one-to-one with the steam supply main pipe 11, the first steam inlet of deaerator 5, and the first steam inlet of auxiliary steam header 3. The cold reheat (cold reheat steam) steam source is connected to the cold reheat steam supply main pipe 4, and the cold reheat steam supply main pipe 4 is connected to the cold reheat steam supply branch pipes 41. The cold reheat steam supply main pipe 4 is connected to the steam inlet main pipe 11 and the second steam inlet of the auxiliary steam header 3. Specifically, the cold reheat steam supply main pipe 4 is connected to two cold reheat steam supply branch pipes 41. One cold reheat steam supply branch pipe 41 is connected to the steam inlet main pipe 11, and the other cold reheat steam supply branch pipe 41 is connected to the second steam inlet of the auxiliary steam header 3. The first steam supply port of the auxiliary steam header 3 is connected to the steam inlet main pipe 11 through the first steam supply pipe 31. The second steam supply port of the auxiliary steam header 3 is connected to the second steam inlet of the deaerator 5 through the second steam supply pipe 32. The top of the deaerator 5 is provided with a steam exhaust port, which is connected to a steam exhaust main pipe 51. The steam exhaust main pipe 51 is connected to multiple steam exhaust branch pipes 52, which are arranged in parallel. Each steam exhaust branch pipe 52 is provided with a pneumatic shut-off valve 53. The multiple steam exhaust branch pipes 52 are respectively connected to the steam exhaust outlet pipe 55. The controller is electrically connected to the pneumatic shut-off valve 53 and can control the opening and closing of the pneumatic shut-off valve 53.
[0022] The working principle of this embodiment is as follows: the four extraction steam sources supply steam to the steam-driven feedwater pump 1, deaerator 5 and auxiliary steam header 3 respectively through the four extraction steam supply header 2; the cold reheat steam source supplies steam to the steam-driven feedwater pump 1 and auxiliary steam header 3 respectively through the cold reheat steam supply header; and the auxiliary steam header 3 supplies steam to the steam-driven feedwater pump 1 and deaerator 5 respectively. Under normal circumstances, the pneumatic shut-off valve 53 is in the closed state. When the working fluid in the deaerator 5 flashes (when the pressure of the four extraction steam sources suddenly drops due to various situations such as rapid load reduction of the generator set, RB action of the unit, or load shedding caused by power system reasons), the controller controls the pneumatic shut-off valve 53 to open. The steam in the deaerator 5 is discharged through the exhaust header 51 and exhaust branch pipe 52, realizing rapid exhaust of the deaerator 5 to reduce the pressure in the deaerator 5, thereby preventing the working fluid from flowing back due to the pressure in the deaerator 5 being greater than the pressure of the four extraction steam sources and auxiliary steam header 3, and ensuring the normal operation of the unit.
[0023] For example, the unit also includes a first pressure sensor 22 for detecting the pressure in the four-extraction steam supply header 2, a second pressure sensor 56 for detecting the pressure in the deaerator 5, and a third pressure sensor 12 for detecting the pressure in the inlet steam header 11. The first pressure sensor 22, the second pressure sensor 56, and the third pressure sensor 12 are electrically connected to the controller. The controller receives the detection value PA from the first pressure sensor 22, the detection value PB from the second sensor, and the detection value PC from the third sensor. That is, the controller can collect the pressure data of the four-extraction steam supply header 2 in real time. When the pressure values in the steam supply header 2, the deaerator 5, and the inlet steam header 11 differ from PA and PC respectively by a value greater than the set value (based on actual conditions), for example, when PB-PA>0.01Mpa and PB-PC>0.03Mpa, it is determined that the steam supply pressure has suddenly dropped. At this time, the controller controls the pneumatic exhaust valve to open to prevent the working fluid in the deaerator 5 from flowing back. When PB drops to a certain value (basically the same as PA and PC), the controller controls the pneumatic exhaust valves on multiple exhaust branch pipes 52 to close one by one to prevent the deaerator 5 from vibrating.
[0024] For example, this unit also includes a first temperature sensor 13 for detecting the temperature inside the steam inlet header 11, a second temperature sensor 23 for detecting the temperature inside the four-stage extraction steam supply header 2, a third temperature sensor 33 for detecting the temperature inside the auxiliary steam header 3, and a fourth temperature sensor 42 for detecting the temperature inside the cold reheat steam supply branch pipe 41 connected to the steam inlet header 11. The first temperature sensor 13, the second temperature sensor 23, the third temperature sensor 33, and the fourth temperature sensor 42 are electrically connected to the controller. The detection value of the first temperature sensor 13 is TA, and the second temperature sensor 23... The detection value of the first temperature sensor is TB, the detection value of the third temperature sensor 33 is TC, and the detection value of the fourth temperature sensor 42 is TD. The controller combines the collected temperature and pressure values to determine whether the steam supply pressure has suddenly dropped. For example, if PB-PA > 0.01Mpa, PB-PC > 0.03Mpa, and TB temperature is low (TB < 350℃) and TB drops rapidly (> 10℃ / min), then it is determined that the steam supply pressure has suddenly dropped, and the judgment result is more accurate. In addition, when the change rate of TA, TB, TC, and TD is large, the controller will issue an alarm to remind the staff to strengthen monitoring and ensure the safe operation of the unit.
[0025] For example, the first pressure sensor 22, the second pressure sensor 56, and the third pressure sensor 12 are each provided with multiple detection points, and the first temperature sensor 13, the second temperature sensor 23, the third temperature sensor 33, and the fourth temperature sensor 42 are each provided with multiple detection points. The average value of the values detected by multiple detection points is taken as the detection value, which is more accurate. For example, the first pressure sensor 22 is provided with three detection points, and the detection values of the three detection points are PA1, PA2, and PA3, respectively. At this time, the controller calculates the average value of PA1, PA2, and PA3 as PA.
[0026] For example, a manual shut-off valve 54 is provided on the exhaust branch pipe 52. Under normal circumstances, the manual shut-off valve 54 is in the open state, which is used to facilitate isolation when the corresponding pneumatic shut-off valve 53 fails.
[0027] For example, the exhaust branch pipe 52 includes a first branch pipe 521, a second branch pipe 522, and a third branch pipe 523. The diameter of the first branch pipe 521 is larger than the diameter of the second branch pipe 522, and the diameter of the second branch pipe 522 is larger than the diameter of the third branch pipe 523. That is, the exhaust flow rates of the first branch pipe 521, the second branch pipe 522, and the third branch pipe 523 are different. The controller can control the pneumatic exhaust valve on one or more of the first branch pipe 521, the second branch pipe 522, and the third branch pipe 523 to open according to the specific situation.
[0028] For example, a first check valve 211 and a first shut-off valve 212 are provided on the four-extraction steam supply branch pipe 21 connected to the first steam inlet of the deaerator 5 to prevent the internal working fluid of the deaerator 5 from flowing back to the four-extraction steam supply main pipe 2 through the four-extraction steam supply branch pipe 21 when the pressure inside the deaerator 5 is higher than the pressure inside the four-extraction steam supply main pipe 2. A second check valve 321 and a second shut-off valve 322 are provided on the first steam supply pipe 31 to prevent the internal working fluid of the deaerator 5 from flowing back to the auxiliary steam supply main pipe 3 through the first steam supply branch pipe when the pressure inside the deaerator 5 is higher than the pressure inside the auxiliary steam header 3. In this embodiment, the first shut-off valve 212 and the second shut-off valve 322 are electric valves, and the first shut-off valve 212 and the second shut-off valve 322 are electrically connected to the controller so that the controller can open and close them.
[0029] For example, the exhaust outlet pipe 55 is connected to a hydrophobic expansion tank to collect and recover the discharged steam, thus avoiding resource loss.
[0030] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.
Claims
1. A steam-driven feedwater pump unit capable of rapid steam discharge, characterized in that: The system includes a steam-driven feedwater pump, a four-extraction steam supply main pipe, an auxiliary steam header, a cold reheat steam supply main pipe, a deaerator, and a controller. The steam inlet of the steam-driven feedwater pump is connected to the steam inlet main pipe. The four-extraction steam supply main pipe is connected to the steam inlet main pipe, the first steam inlet of the deaerator, and the first steam inlet of the auxiliary steam header via four-extraction steam supply branch pipes. The cold reheat steam supply main pipe is connected to the steam inlet main pipe and the second steam inlet of the auxiliary steam header via cold reheat steam supply branch pipes. The first steam inlet of the auxiliary steam header is connected to the steam inlet main pipe via a first steam supply pipe. The second steam inlet of the auxiliary steam header is connected to the second steam inlet of the deaerator via a second steam supply pipe. The top of the deaerator is equipped with a steam exhaust port, which is connected to a steam exhaust main pipe. The steam exhaust main pipe is connected to multiple steam exhaust branch pipes, each equipped with a pneumatic shut-off valve. The multiple steam exhaust branch pipes are respectively connected to a steam exhaust outlet pipe. The controller is electrically connected to the pneumatic shut-off valve.
2. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 1, characterized in that: It also includes a first pressure sensor for detecting the pressure in the four-extraction steam supply header, a second pressure sensor for detecting the pressure in the deaerator, and a third pressure sensor for detecting the pressure in the steam inlet header. The first pressure sensor, the second pressure sensor, and the third pressure sensor are electrically connected to the controller.
3. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 2, characterized in that: It also includes a first temperature sensor for detecting the temperature inside the steam inlet header, a second temperature sensor for detecting the temperature inside the four extraction steam supply header, a third temperature sensor for detecting the temperature inside the auxiliary steam header, and a fourth temperature sensor for detecting the temperature inside the cold reheat steam supply branch pipe connected to the steam inlet header. The first, second, third, and fourth temperature sensors are electrically connected to the controller.
4. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 2, characterized in that: The first pressure sensor, the second pressure sensor, and the third pressure sensor are each equipped with multiple detection points.
5. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 3, characterized in that: The first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor are each equipped with multiple detection points.
6. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 1, characterized in that: The exhaust branch pipe is equipped with a manual shut-off valve.
7. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 1, characterized in that: The exhaust branch pipe includes a first branch pipe, a second branch pipe, and a third branch pipe. The diameter of the first branch pipe is larger than the diameter of the second branch pipe, and the diameter of the second branch pipe is larger than the diameter of the third branch pipe.
8. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 1, characterized in that: The four-extraction steam supply branch pipe connected to the first steam inlet of the deaerator is equipped with a first check valve and a first shut-off valve.
9. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 1, characterized in that: The first steam supply pipe is equipped with a second check valve and a second shut-off valve.
10. The steam-driven feedwater pump unit capable of rapid steam discharge according to claim 1, characterized in that: The exhaust outlet pipe is connected to the hydrophobic expansion container.