Apparatus for optimizing and improving steam-driven feedwater pump and system thereof, and operation method of apparatus

Abstract

An apparatus for optimizing and improving a steam-driven feedwater pump and a system thereof, and an operation method of the apparatus. The apparatus comprises a deaerator (1), a first feedwater pump set, a unit drainage tank (22), a feedwater pump filter screen drainage manual valve (17), a steam pump booster pump filter screen drainage manual valve (15), a feedwater pump outlet electric valve (13), a deaerator outlet electric valve (10), a second feedwater pump set (9), a high-pressure heater system (8), a steam pump booster pump filter screen (2) and a feedwater pump filter screen (4). The first feedwater pump set comprises a steam pump booster pump (3), a steam-driven feedwater pump (5) and a feedwater pump steam turbine (6). According to the apparatus and the operation method thereof, the filter screens can be cleaned when the feedwater pump steam turbine is in a turning gear state, improving the operation safety of the system.

Description

A steam-driven water supply pump and its system optimization and improvement device and its operation method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on November 23, 2023, with application number 202311578539.0 and invention name “A pneumatic water supply pump and its system optimization and improvement device and its working method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the technical field of water supply systems in power plants, and relates to a pneumatic water supply pump, a device for optimizing and improving the system, and a working method thereof. Background Art

[0004] A power plant's feedwater system primarily consists of a deaerator, feedwater pumps, high-pressure heaters, filters, and valves. Its primary function is to increase the pressure of the main condensate from the deaerator through the feedwater pumps. After further heating through multi-stage high-pressure heaters to meet boiler feedwater requirements, the condensate is then transported to the boiler economizer inlet. The feedwater pumps are a crucial component of the feedwater system. Currently, most domestic power plants utilize a combination of a steam-driven feedwater pump and an electric feedwater pump.

[0005] A steam-driven feedwater pump system primarily consists of a steam-driven feedwater pump, a steam-driven pre-pump, a feedwater turbine, and a filter. Large thermal power generating units typically have two pre-pump filters: a primary filter and a backup filter. Small and medium-sized thermal power generating units only have one pre-pump filter. If the filter becomes clogged, the feedwater turbine must be shut down for cleaning. After the turbine is shut down, it must be immediately cranked, and the steam-driven feedwater pump must be fully filled with water during this operation. However, the water in the pipes must be drained before cleaning the filter, and the power plant's existing operating system cannot isolate the pre-pump filter from the steam-driven feedwater pump. Therefore, filter cleaning can only be performed after cranking has stopped. This significantly increases equipment maintenance time and costs, impacting the efficient operation of the unit. Therefore, it is necessary to optimize and improve the steam-driven feedwater pump system.

[0006] Summary of the Invention

[0007] The purpose of this application is to overcome the shortcomings of the above-mentioned prior art and provide a device and working method for optimizing and improving a pneumatic feedwater pump and its system. The device and its working method can clean the filter when the feedwater pump turbine is in the cranking state, thereby improving the safety of the system operation.

[0008] To achieve the above-mentioned objectives, the steam-driven feedwater pump and its system optimization and improvement device described in the present application include a deaerator, a first feedwater pump unit, a unit drainage tank, a feedwater pump filter screen drainage manual valve, a steam pump pre-pump filter screen drainage manual valve, a feedwater pump outlet electric valve, a deaerator outlet electric valve, a second feedwater pump unit, a high-pressure heater system, a steam pump pre-pump filter screen and a feedwater pump filter screen; the first feedwater pump unit includes a steam pump pre-pump, a steam-driven feedwater pump and a feedwater pump steam turbine;

[0009] The feedwater pump steam turbine is coaxially arranged with the steam-driven feedwater pump. The steam-driven feedwater pump and the steam pump pre-pump are connected via a reduction gearbox. The condensate outlet of the deaerator is connected to the inlet of the high-pressure heater system via the deaerator outlet electric valve, the steam pump pre-pump filter, the steam pump pre-pump, the feedwater pump filter, the steam-driven feedwater pump and the feedwater pump outlet electric valve in sequence. The condensate outlet of the deaerator is connected to the inlet of the high-pressure heater system via the second feedwater pump group.

[0010] The drain outlet of the steam pump pre-pump filter is connected to the unit drain tank through the steam pump pre-pump filter manual drain valve, and the feed water pump filter is connected to the unit drain tank through the feed water pump filter manual drain valve; the condensate outlet of the deaerator is connected to the inlet of the steam-driven feed water pump through the feed water pipe, and a feed water electric valve is provided on the feed water pipe.

[0011] The outlet of the steam-driven feed water pump is connected to the inlet of the high-pressure heater system through the feed water pump outlet check valve and the feed water pump outlet electric valve in sequence.

[0012] A steam-driven water supply pump inlet pressure measuring point is provided at the inlet of the steam-driven water supply pump;

[0013] A steam-driven water supply pump outlet pressure measuring point is provided at the outlet of the steam-driven water supply pump;

[0014] The front and rear sides of the steam pump pre-pump filter are provided with steam pump pre-pump filter differential pressure measuring points;

[0015] Water pump filter differential pressure measuring points are set on the front and rear sides of the water pump filter.

[0016] The outlet of the pneumatic feed water pump and the pipeline of the feed water pump outlet check valve are connected to the external environment through the manual valve of the air exhaust pipeline.

[0017] The second water supply pump group is a steam-driven water supply pump or an electric water supply pump.

[0018] The inlet of the feedwater pump turbine is connected to the fourth stage steam extraction pipeline of the main engine in the steam extraction heat recovery system.

[0019] It also includes a condenser, and the exhaust port of the feedwater pump turbine is connected to the inlet of the condenser.

[0020] It also includes a control system. A float type liquid level switch, a float type liquid level switch and a control system are arranged at the highest position of the pipeline between the outlet of the pneumatic water supply pump and the water supply pump outlet check valve.

[0021] The operating method of the steam-driven water supply pump and the device for optimizing and improving the system thereof described in the present application comprises the following steps:

[0022] When the system operates normally, the deaerator outlet electric valve, feedwater pump inlet electric valve and feedwater pump outlet electric valve are opened, and the feedwater pump turbine drives the steam-driven feedwater pump and the steam pump pre-pump to operate, extracting condensate from the deaerator and sending it to the high-pressure heater system;

[0023] When the differential pressure of the front and rear sides of the steam pump pre-pump filter or the feed water pump filter is greater than 0.1MPa, the first feed water pump group is shut down and the second feed water pump group is put into operation. After the feed water pump turbine idling is completed and the cranking is started, first close the feed water pump inlet electric valve and the feed water pump outlet electric valve to isolate the steam-driven feed water pump and ensure that the steam-driven feed water pump is in a full water state. Then close the deaerator outlet electric valve, open the drain pipe angle valve, the feed water pump filter drain manual valve and the steam pump pre-pump filter drain manual valve to drain the water in the pipeline, then close the steam pump pre-pump filter drain manual valve and the feed water pump filter drain manual valve to clean the filter.

[0024] When the filter is being cleaned, the feedwater pump turbine is in the cranking state to ensure that the steam-driven feedwater pump is in a full water state.

[0025] This application has the following beneficial effects:

[0026] During specific operation of the pneumatic feed water pump and its system optimization and improvement device and its working method described in the present application, when the steam pump pre-pump filter or the feed water pump filter is blocked, that is, the differential pressure between the front and rear sides of the steam pump pre-pump filter or the feed water pump filter is greater than 0.1MPa, the first feed water pump group is shut down and the second feed water pump group is put into operation, the pneumatic feed water pump is effectively isolated, and the pneumatic feed water pump is in a full water state. Then, the steam pump pre-pump filter and the feed water pump filter are cleaned, and while cleaning the filter, the normal operation of the feed water pump turbine is guaranteed, thereby reducing maintenance costs and improving the safety of system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a schematic diagram of the structure of this application.

[0028] Among them, 1 is the deaerator, 2 is the steam pump pre-pump filter, 3 is the steam pump pre-pump, 4 is the feed water pump filter, 5 is the steam-driven feed water pump, 6 is the feed water pump turbine, 7 is the reduction gear box, 8 is the high-pressure heater system, 9 is the second feed water pump group, 10 is the deaerator outlet electric valve, 11 is the feed water pump inlet electric valve, 12 is the feed water pump outlet check valve, 13 is the feed water pump outlet electric valve, 14 is the water supply electric valve, 15 is the steam pump pre-pump filter drain manual valve, 16 is the drain pipe angle valve, 17 is the feed water pump filter drain manual valve, 18 is the air exhaust pipe manual valve, 19 is the float type liquid level switch, 20 is the fourth stage steam extraction pipe of the main engine, 21 is the condenser, 22 is the unit drain tank, 23 is the external environment, 24 is the control system, P1 is the steam feed water pump inlet pressure measuring point, P2 is the steam feed water pump outlet pressure measuring point, P3 is the steam pump pre-pump filter differential pressure measuring point, and P4 is the feed water pump filter differential pressure measuring point. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments, and are not intended to limit the scope of disclosure of the present application. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of this application.

[0030] The accompanying drawings illustrate schematic diagrams of the structures of the embodiments disclosed herein. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0031] 1 , the steam-driven feedwater pump and its system optimization and improvement device described in this application includes a deaerator 1, a first feedwater pump group, a second feedwater pump group 9, a high-pressure heater system 8, a steam pump pre-pump filter 2, and a feedwater pump filter 4;

[0032] Among them, the first feed water pump group includes a steam pump pre-pump 3, a steam-driven feed water pump 5 and a feed water pump turbine 6. The feed water pump turbine 6 is arranged coaxially with the steam-driven feed water pump 5. The steam-driven feed water pump 5 and the steam pump pre-pump 3 are connected through a reduction gearbox 7.

[0033] The condensate outlet of the deaerator 1 is connected to the high-pressure heater system 8 in sequence through the deaerator outlet electric valve 10, the steam pump pre-pump filter 2, the steam pump pre-pump 3, the feed water pump filter 4 and the steam-driven feed water pump 5. The fourth-stage steam extraction pipeline 20 of the main engine in the steam extraction heat recovery system is connected to the inlet of the feed water pump turbine 6, and the exhaust port of the feed water pump turbine 6 is connected to the inlet of the condenser 21.

[0034] The outlet of the pneumatic feed water pump 5 is connected to the inlet of the high-pressure heater system 8 through the feed water pump outlet check valve 12 and the feed water pump outlet electric valve 13 in turn, and the condensate outlet of the deaerator 1 is connected to the inlet of the high-pressure heater system 8 through the second feed water pump group 9. A pneumatic feed water pump inlet pressure measuring point P1 is provided at the inlet of the pneumatic feed water pump 5, and a pneumatic feed water pump outlet pressure measuring point P2 is provided at the outlet of the pneumatic feed water pump 5. A steam pump pre-pump filter differential pressure measuring point P3 is provided on the front and rear sides of the steam pump pre-pump filter 2, and a feed water pump filter differential pressure measuring point P4 is provided on the front and rear sides of the feed water pump filter 4.

[0035] The drain outlet of the steam pump pre-pump filter 2 is connected to the unit drain tank 22 through the steam pump pre-pump filter drain manual valve 15, and the feed water pump filter 4 is connected to the unit drain tank 22 through the feed water pump filter drain manual valve 17;

[0036] The outlet of the pneumatic water pump 5 and the pipeline of the water pump outlet check valve 12 are connected to the external environment 23 through the air exhaust pipe manual valve 18. A float type liquid level switch 19 is provided at the highest position of the pipeline of the pneumatic water pump 5 and the water pump outlet check valve 12, and the float type liquid level switch 19 is connected to the control system 24.

[0037] The condensate outlet of the deaerator 1 is connected to the inlet of the steam-driven water supply pump 5 through a water supply pipe, and a water supply electric valve 14 is provided on the water supply pipe.

[0038] The second water supply pump group 9 is a steam-driven water supply pump or an electric water supply pump.

[0039] The operating method of the steam-driven water supply pump and the device for optimizing and improving the system thereof described in the present application comprises the following steps:

[0040] When the system is operating normally, the deaerator outlet electric valve 10, the feedwater pump inlet electric valve 11 and the feedwater pump outlet electric valve 13 are opened, and the fourth-stage extraction steam of the main engine enters the feedwater pump turbine 6 to perform work, thereby driving the steam-driven feedwater pump 5 and the steam pump pre-pump 3 to operate, extracting condensate from the deaerator 1 and sending it to the high-pressure heater system 8. During this process, the values ​​of the steam-driven feedwater pump inlet pressure measuring point P1, the steam-driven feedwater pump outlet pressure measuring point P2, the steam pump pre-pump filter differential pressure measuring point P3 and the feedwater pump filter differential pressure measuring point P4 are observed in real time to maintain normal operation of the system;

[0041] When the pressure difference between the front and rear sides of the steam pump pre-pump filter 2 or the feed water pump filter 4 is greater than 0.1MPa, resulting in fluctuations in the value of the steam feed water pump outlet pressure measuring point P2, it means that the steam pump pre-pump filter 2 or the feed water pump filter 4 has been seriously clogged, affecting the normal operation of the system. At this time, the first feed water pump group is shut down and the second feed water pump group 9 is put into operation. When the feed water pump turbine 6 is idle and the cranking is put into operation, first close the feed water pump inlet electric valve 11 and the feed water pump outlet electric valve 13 to isolate the steam feed water pump 5 and ensure that the steam feed water pump 5 is in a full water state, then close the deaerator outlet electric valve 10, open the drain pipe angle valve 16, the feed water pump filter drain manual valve 17 and the steam pump pre-pump filter drain manual valve 15 to drain the water in the pipeline, then close the steam pump pre-pump filter drain manual valve 15 and the feed water pump filter drain manual valve 17 to clean the filter;

[0042] When the filter is being cleaned, the feedwater pump turbine 6 is still in the cranking state to ensure that the steam-driven feedwater pump 5 is in a full water state, to avoid the possibility of dry grinding of the steam-driven feedwater pump 5, which may cause damage to the equipment. When the values ​​of the steam-driven feedwater pump inlet pressure measuring point P1 and the steam-driven feedwater pump outlet pressure measuring point P2 fluctuate, or the float-type liquid level switch 19 displays a closed feedback signal, it means that the steam-driven feedwater pump 5 is not in a full water state. At this time, open the water supply electric valve 14 and the air exhaust line manual valve 18. When the values ​​of the steam-driven feedwater pump inlet pressure measuring point P1 and the steam-driven feedwater pump outlet pressure measuring point P2 are stable, the float-type liquid level switch 19 displays an open feedback signal, and there is continuous water outflow from the air exhaust line, it means that the steam-driven feedwater pump 5 is in a full water state. Close the water supply electric valve 14 and the air exhaust line manual valve 18.

[0043] When it takes a long time to clean the filter, and when the cylinder temperature of the feedwater pump turbine 6 is less than 150°C, the cranking can be stopped. At this time, the steam-driven feedwater pump 5 does not need to be in a full water state all the time, and all valves in the system are in a closed state;

[0044] When the steam pump pre-pump filter 2 and the water supply pump filter 4 are cleaned and reinstalled, the steam-driven water supply pump 5 returns to normal and is in standby status.

[0045] This application is applicable to, but not limited to, thermal power generation units. The foregoing description illustrates the basic principles, main features, and advantages of this application. This application is not limited to the aforementioned embodiments; the aforementioned embodiments and description merely illustrate the principles of this application. This application is subject to various changes and improvements during actual design and construction, and all such changes and improvements fall within the scope of protection claimed in this application.

Claims

1. A steam-driven water supply pump and a device for optimizing and improving its system, characterized in that: It comprises a deaerator (1), a first feedwater pump unit, a unit drainage tank (22), a feedwater pump filter screen drainage manual valve (17), a steam pump pre-pump filter screen drainage manual valve (15), a feedwater pump outlet electric valve (13), a deaerator outlet electric valve (10), a second feedwater pump unit (9), a high-pressure heater system (8), a steam pump pre-pump filter screen (2) and a feedwater pump filter screen (4); the first feedwater pump unit comprises a steam pump pre-pump (3), a steam-driven feedwater pump (5) and a feedwater pump steam turbine (6); The feedwater pump turbine (6) is coaxially arranged with the steam-driven feedwater pump (5); the steam-driven feedwater pump (5) is connected to the steam pump pre-pump (3) via a reduction gearbox (7); the condensate outlet of the deaerator (1) is connected to the inlet of the high-pressure heater system (8) via the deaerator outlet electric valve (10), the steam pump pre-pump filter (2), the steam pump pre-pump (3), the feedwater pump filter (4), the steam-driven feedwater pump (5) and the feedwater pump outlet electric valve (13); the condensate outlet of the deaerator (1) is connected to the inlet of the high-pressure heater system (8) via the second feedwater pump group (9); The drainage outlet of the steam pump pre-pump filter (2) is connected to the unit drainage groove (22) through the steam pump pre-pump filter drainage manual valve (15), and the feed water pump filter (4) is connected to the unit drainage groove (22) through the feed water pump filter drainage manual valve (17); the condensate outlet of the deaerator (1) is connected to the inlet of the steam-driven feed water pump (5) through a feed water pipeline, and a feed water electric valve (14) is provided on the feed water pipeline.

2. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: The outlet of the steam-driven water supply pump (5) is connected to the inlet of the high-pressure heater system (8) via the water supply pump outlet check valve (12) and the water supply pump outlet electric valve (13) in sequence.

3. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: A steam-driven water supply pump inlet pressure measuring point (P1) is provided at the inlet of the steam-driven water supply pump (5); A steam-driven water supply pump outlet pressure measuring point (P2) is provided at the outlet of the steam-driven water supply pump (5); Steam pump pre-pump filter screen differential pressure measuring points (P3) are arranged on the front and rear sides of the steam pump pre-pump filter screen (2).

4. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: Water feed pump filter screen differential pressure measuring points (P4) are arranged on the front and rear sides of the water feed pump filter screen (4).

5. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: The outlet of the steam-driven water supply pump (5) and the pipeline of the water supply pump outlet check valve (12) are connected to the external environment (23) through the air exhaust pipeline manual valve (18).

6. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: The second water supply pump group (9) is a steam-driven water supply pump or an electric water supply pump.

7. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: The inlet of the feedwater pump steam turbine (6) is connected to the fourth-stage steam extraction pipeline (20) of the main engine in the steam extraction heat recovery system.

8. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: It also includes a condenser (21), and the exhaust port of the feedwater pump turbine (6) is connected to the inlet of the condenser (21).

9. The steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: It also includes a control system (24), a float type liquid level switch (19) is arranged at the highest position of the pipeline between the outlet of the steam-driven water supply pump (5) and the water supply pump outlet check valve (12), and the float type liquid level switch (19) and the control system (24).

10. An operating method of the steam-driven water supply pump and the device for optimizing and improving the system thereof according to claim 1, characterized in that: The following steps are involved: When the system operates normally, the deaerator outlet electric valve (10), the feedwater pump inlet electric valve (11) and the feedwater pump outlet electric valve (13) are opened, and the feedwater pump turbine (6) drives the steam-driven feedwater pump (5) and the steam pump pre-pump (3) to operate, extracting condensate from the deaerator (1) and sending it to the high-pressure heater system (8); When the differential pressure between the front and rear sides of the steam pump pre-pump filter (2) or the feed water pump filter (4) is greater than 0.1 MPa, the first feed water pump group is stopped and the second feed water pump group (9) is put into operation. When the feed water pump turbine (6) is idled and the cranking is started, the feed water pump inlet electric valve (11) and the feed water pump outlet electric valve (13) are first closed to isolate the steam-driven feed water pump (5) and ensure that the steam-driven feed water pump (5) is in a full water state. Then, the deaerator outlet electric valve (10) is closed, and the drain pipe angle valve (16), the feed water pump filter drain manual valve (17) and the steam pump pre-pump filter drain manual valve (15) are opened to drain the water in the pipeline. Then, the steam pump pre-pump filter drain manual valve (15) and the feed water pump filter drain manual valve (17) are closed to clean the filter. When the filter screen is being cleaned, the feedwater pump steam turbine (6) is in a cranking state, ensuring that the steam-driven feedwater pump (5) is in a full water state.

Images