A system and method for switching steam source of steam-driven feedwater pumps suitable for deep peak regulation

Abstract

The present invention discloses a system and method for switching the steam source of a steam-driven feedwater pump suitable for deep peak regulation, comprising a small machine low-pressure steam inlet pipeline, a small machine debugging steam pipeline, a small machine deep peak regulation steam pipeline, a steam inlet pipeline and a steam-driven feedwater pump; the outlet of the small machine low-pressure steam inlet pipeline, the outlet of the small machine debugging steam pipeline and the outlet of the small machine deep peak regulation steam pipeline are all connected with the inlet of the steam inlet pipeline, and the outlet of the steam inlet pipeline is connected with the inlet of the steam-driven feedwater pump. The system and method can realize the whole process control of the steam-driven feedwater pump from startup and commissioning, normal operation and deep peak regulation low load operation, and improve the operating stability and safety of the steam inlet system of the steam-driven feedwater pump.

Description

Technical Field

[0001] The invention belongs to the field of automatic control of steam-water systems in thermal power plants, and relates to a system and method for switching steam sources of steam-driven feedwater pumps suitable for deep peak regulation. Background Art

[0002] In order to absorb new energy power generation, more and more thermal power generating units are undergoing flexibility transformation. With the reduction of deep peak load of the units, many problems have also emerged. Under the deep peak load condition of the unit, the reduction of the four-stage steam extraction parameters cannot meet the minimum steam inlet parameter requirements of the steam-driven feedwater pump. In order to solve the operation problem of the steam-driven feedwater pump under the deep peak load condition of the unit and create conditions for further reduction of the unit load, it is necessary to propose a system and method to solve the system control problem of the steam-driven feedwater pump under the deep peak load condition. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a system and method for switching the steam source of a steam-driven feedwater pump that is suitable for deep peak regulation. The system and method can realize the whole process control of the steam-driven feedwater pump from startup and debugging, normal operation and deep peak regulation low-load operation, thereby improving the operating stability and safety of the steam inlet system of the steam-driven feedwater pump.

[0004] To achieve the above-mentioned purpose, the steam source switching system of the steam-driven feedwater pump adapted to deep peak regulation of the present invention comprises a small machine low-pressure steam inlet pipeline, a small machine debugging steam pipeline, a small machine deep peak regulation steam pipeline, a steam inlet pipeline and a steam-driven feedwater pump;

[0005] The outlet of the small unit low-pressure steam inlet pipeline, the outlet of the small unit debugging steam pipeline and the outlet of the small unit deep peak regulation steam pipeline are all connected to the inlet of the steam inlet pipeline, and the outlet of the steam inlet pipeline is connected to the inlet of the steam-driven feed water pump;

[0006] The small machine low-pressure steam inlet pipeline is provided with a second pressure gauge, a second thermometer, a second electric door and a first flow meter in sequence along the working medium flow direction;

[0007] A third pressure gauge, a third thermometer and a third electric door are sequentially arranged on the steam pipeline for small unit debugging along the working medium flow direction;

[0008] A fourth pressure gauge, a fourth thermometer, a fourth electric door, a first regulating valve and a second flow meter are sequentially arranged on the steam pipeline for deep peak regulation of the small unit along the flow direction of the working medium;

[0009] A first pressure gauge, a first thermometer and a first electric door are sequentially arranged on the steam inlet pipeline along the flow direction of the working medium.

[0010] The pipeline between the first flow meter and the second electric door is connected to the auxiliary steam header through the auxiliary steam header steam supply pipeline.

[0011] The pipeline between the first flow meter and the second electric door is connected to the deaerator through the deaerator steam supply pipeline.

[0012] A first pressure gauge, a first thermometer, a first electric door and a first fast-closing check valve are sequentially arranged on the steam inlet pipeline along the flow direction of the working medium.

[0013] A second pressure gauge, a second thermometer, a second fast-closing check valve, a second electric door, a first flow meter and a first check valve are sequentially arranged on the small machine low-pressure steam inlet pipeline along the working medium flow direction.

[0014] A fourth pressure gauge, a fourth thermometer, a fourth electric door, a first regulating valve, a second flow meter and a second check valve are sequentially arranged on the steam pipeline for deep peak regulation of the small unit along the flow direction of the working medium.

[0015] The method for switching the steam source of a steam-driven feedwater pump adapted to deep peak regulation of the present invention comprises the following steps:

[0016] 1) Set the minimum temperature value t of the steam inlet of the steam-driven feedwater pump zd And the minimum pressure value P zd , set the normal operating temperature value t yx And normal operating pressure value P yx , set the alarm temperature value t bj And alarm pressure value P bj ;

[0017] 2) When the unit is in the stage of commissioning the steam-driven feedwater pump, the actual temperature t3 of the commissioning steam detected by the third thermometer is greater than or equal to t zd And the pressure P3 detected by the third pressure gauge is greater than or equal to P zd When the actual temperature t1 of the steam inlet of the steam-driven feedwater pump detected by the first thermometer is greater than or equal to t zd The pressure P1 detected by the first pressure gauge is greater than or equal to P zd , then open the first electric door to debug the steam-driven feedwater pump. During the debugging process, the actual temperature t1 of the steam inlet of the steam-driven feedwater pump detected by the first thermometer and the pressure P1 detected by the first pressure gauge are respectively less than the set alarm temperature value t bj And alarm pressure value P bj When the actual temperature t2 of the small engine low-pressure steam detected by the second thermometer is greater than or equal to t zd The pressure P2 detected by the second pressure gauge is greater than or equal to P zd When , go to step 3);

[0018] 3) After the unit is started, when the actual temperature t2 of the small unit low-pressure steam detected by the second thermometer is greater than or equal to t tsThe pressure P2 detected by the second pressure gauge is greater than or equal to P ts When the second electric door is opened and the third electric door is closed to switch the steam source of the steam-driven feedwater pump, the actual temperature t1 of the steam inlet of the steam-driven feedwater pump detected by the first thermometer and the pressure P1 detected by the first pressure gauge are respectively less than or equal to the set alarm temperature value t bj And alarm pressure value P bj ; When the unit load decreases, the measured temperature t2 of the low-pressure steam used by the small unit detected by the second thermometer approaches t ts Or the pressure P2 detected by the second pressure gauge is close to P ts When the load needs to be further reduced, go to step 4);

[0019] 4) When the actual temperature t4 of the steam used for deep peak load regulation of the small unit detected by the fourth thermometer is greater than or equal to t zd And the pressure P4 detected by the fourth pressure gauge is greater than or equal to P zd When the fourth electric door is opened, the steam parameters for deep peak regulation of the small machine are adjusted through the first regulating valve.

[0020] In step 4), when the actual temperature t4 of the steam used for deep peak load regulation of the small machine detected by the fourth thermometer approaches t zd Or the pressure P4 detected by the fourth pressure gauge is close to P zd When the steam-driven water supply pump does not have the conditions to reduce the load again.

[0021] The present invention has the following beneficial effects:

[0022] The system and method for switching the steam source of a steam-driven feed water pump adapted to deep peak regulation described in the present invention, during specific operation, performs real-time detection and accurate calculation of the steam inlet parameters of each steam inlet branch of the steam-driven feed water pump, obtains the steam source selection most suitable for the operation of the steam-driven feed water pump under the current load, completes the steam-driven feed water pump's following of the operating conditions under different load conditions, realizes the whole process control of the steam-driven feed water pump from startup debugging, normal operation and deep peak regulation low load operation, and improves the operating stability and safety of the steam inlet system of the steam-driven feed water pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a system diagram of the present invention;

[0024] Among them, 1 is a steam-driven water supply pump, 2 is a first fast-closing check valve, 3 is a first electric door, 4 is a first thermometer, 5 is a first pressure gauge, 6 is a first check valve, 7 is a first flow meter, 8 is a deaerator steam supply pipeline, 9 is an auxiliary steam manifold steam supply pipeline, 10 is a second electric door, 11 is a second fast-closing check valve, 12 is a second thermometer, 13 is a second pressure gauge, 14 is a third electric door, 15 is a third thermometer, 16 is a third pressure gauge, 17 is a second check valve, 18 is a second flow meter, 19 is a first regulating valve, 20 is a fourth electric door, 21 is a fourth thermometer, and 22 is a fourth pressure gauge. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0026] The accompanying drawings show schematic diagrams of structures according to embodiments disclosed in the present invention. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0027] refer to Figure 1 The steam source switching system of the steam-driven feedwater pump adapted to deep peak regulation of the present invention comprises a small machine low-pressure steam inlet pipeline, a small machine debugging steam pipeline, a small machine deep peak regulation steam pipeline, a steam inlet pipeline and a steam-driven feedwater pump 1;

[0028] The outlet of the small unit low-pressure steam inlet pipeline, the outlet of the small unit debugging steam pipeline and the outlet of the small unit deep peak regulation steam pipeline are all connected with the inlet of the steam inlet pipeline, and the outlet of the steam inlet pipeline is connected with the inlet of the steam-driven feed water pump 1. The second pressure gauge 13, the second thermometer 12, the second fast-closing check valve 11, the second electric door 10, the first flow meter 7 and the first check valve 6 are sequentially arranged on the small unit low-pressure steam inlet pipeline along the working medium flow direction, wherein the pipeline between the first flow meter 7 and the second electric door 10 is connected to the auxiliary steam manifold through the auxiliary steam manifold steam supply pipeline 9, and the pipeline between the first flow meter 7 and the second electric door 10 is connected to the deaerator through the deaerator steam supply pipeline 8.

[0029] A third pressure gauge 16, a third thermometer 15 and a third electric door 14 are sequentially arranged on the steam pipeline for small machine debugging along the working medium flow direction;

[0030] A fourth pressure gauge 22, a fourth thermometer 21, a fourth electric door 20, a first regulating valve 19, a second flow meter 18 and a second check valve 17 are sequentially arranged on the steam pipeline for deep peak regulation of the small unit along the flow direction of the working medium;

[0031] A first pressure gauge 5, a first thermometer 4, a first electric door 3 and a first fast-closing check valve 2 are sequentially arranged on the steam inlet pipeline along the working medium flow direction;

[0032] The first check valve 6 and the second check valve 17 prevent the steam supply systems from being reversed.

[0033] The method for switching the steam source of a steam-driven feedwater pump adapted to deep peak regulation of the present invention comprises the following steps:

[0034] 1) Set the minimum temperature value t of the steam inlet of the steam-driven feedwater pump 1 zd And the minimum pressure value P zd , set the normal operating temperature value t yx And normal operating pressure value P yx , set the alarm temperature value t bj And alarm pressure value P bj ;

[0035] 2) When the unit is in the stage of not starting the steam-driven feedwater pump 1 for debugging, when the actual temperature t3 of the debugging steam detected by the third thermometer 15 is greater than or equal to t zd The pressure P3 detected by the third pressure gauge 16 is greater than or equal to P zd When the actual temperature t1 of the steam inlet of the steam-driven feedwater pump 1 detected by the first thermometer 4 is greater than or equal to t zd The pressure P1 detected by the first pressure gauge 5 is greater than or equal to P zd; then open the first electric door 3 to debug the steam-driven water supply pump 1. During the debugging process, the actual temperature t1 of the steam inlet of the steam-driven water supply pump 1 detected by the first thermometer 4 and the pressure P1 detected by the first pressure gauge 5 are respectively less than the set alarm temperature value t bj And alarm pressure value P bj When the small machine low pressure steam measured temperature t2 detected by the second thermometer 12 is greater than or equal to t zd The pressure P2 detected by the second pressure gauge 13 is greater than or equal to P zd When , go to step 3);

[0036] 3) After the unit is started, when the actual temperature t2 of the low-pressure steam used by the small unit detected by the second thermometer 12 is greater than or equal to t ts The pressure P2 detected by the second pressure gauge 13 is greater than or equal to P ts , then open the second electric door 10, close the third electric door 14 to switch the steam source of the steam-driven feedwater pump 1, wherein the actual measured temperature t1 of the steam inlet of the steam-driven feedwater pump 1 detected by the first thermometer 4 and the pressure P1 detected by the first pressure gauge 5 are respectively less than or equal to the set alarm temperature value t bj And alarm pressure value P bj ; When the unit decreases with load, the small unit low-pressure steam measured temperature t2 detected by the second thermometer 12 is close to t ts Or the pressure P2 detected by the second pressure gauge 13 is close to P ts When the load needs to be further reduced, go to step 4);

[0037] 4) When the actual temperature t4 of the steam used for deep peak load regulation of the small unit detected by the fourth thermometer 21 is greater than or equal to t zd The pressure P4 detected by the fourth pressure gauge 22 is greater than or equal to P zd When the fourth electric door 20 is opened, the steam parameters for deep peak load regulation of the small machine are adjusted through the first regulating valve 19. When the actual temperature t4 of the steam for deep peak load regulation of the small machine detected by the fourth thermometer 21 is close to t zd Or the pressure P4 detected by the fourth pressure gauge 22 is close to P zd When the steam-driven water supply pump 1 does not have the conditions for further load reduction, it is necessary to switch to the electric water supply pump for operation or shutdown.

[0038] At the same time, the present invention sets the steam pressure and temperature of the steam-driven feedwater pump 1 as system calculation input parameters. When the unit load changes and the steam inlet parameters change, the steam source is switched in time to ensure the stable operation of the steam-driven feedwater pump 1.

[0039] The present invention introduces the steam flow of the steam-driven water supply pump 1 into the control system and adjusts the flow parameters through a regulating valve to meet the precise control of steam inlet under deep peak-shaving and low-load conditions.

[0040] The present invention performs real-time detection and accurate calculation of the steam inlet parameters of each steam inlet system of the steam-driven feed water pump 1, obtains the steam source selection that is most suitable for the operation of the steam-driven feed water pump 1 under the current load, completes the following of the steam-driven feed water pump 1 under different load conditions, and enables the steam-driven feed water pump 1 to operate safely and stably. At the same time, it also provides conditions for further deep peak regulation of the unit, ensuring long-term stable and safe operation of the unit under deep peak regulation conditions.

Claims

1. A steam source switching system for a steam-driven feedwater pump adapted for deep peak regulation, characterized in that: It includes a small machine low-pressure steam inlet pipeline, a small machine commissioning steam pipeline, a small machine deep peak regulation steam pipeline, a steam inlet pipeline and a steam-driven feed water pump (1); The outlet of the small unit low-pressure steam inlet pipeline, the outlet of the small unit debugging steam pipeline and the outlet of the small unit deep peak regulation steam pipeline are all connected to the inlet of the steam inlet pipeline, and the outlet of the steam inlet pipeline is connected to the inlet of the steam-driven feed water pump (1); A second pressure gauge (13), a second thermometer (12), a second electric door (10) and a first flow meter (7) are sequentially arranged on the small machine low-pressure steam inlet pipeline along the working medium flow direction; A third pressure gauge (16), a third thermometer (15) and a third electric door (14) are sequentially arranged on the steam pipeline for small machine debugging along the working medium flow direction; A fourth pressure gauge (22), a fourth thermometer (21), a fourth electric door (20), a first regulating valve (19) and a second flow meter (18) are sequentially arranged on the steam pipeline for deep peak regulation of the small unit along the flow direction of the working medium; A first pressure gauge (5), a first thermometer (4) and a first electric door (3) are sequentially arranged on the steam inlet pipeline along the working medium flow direction.

2. The system for switching steam source of a steam-driven feedwater pump adapted for deep peak regulation according to claim 1 is characterized in that: The pipeline between the first flow meter (7) and the second electric door (10) is connected to the auxiliary steam header through the auxiliary steam header steam supply pipeline (9).

3. The system for switching steam source of a steam-driven feedwater pump adapted for deep peak regulation according to claim 1 is characterized in that: The pipeline between the first flow meter (7) and the second electric door (10) is connected to the deaerator through the deaerator steam supply pipeline (8).

4. The system for switching steam source of a steam-driven feedwater pump adapted for deep peak regulation according to claim 1 is characterized in that: A first pressure gauge (5), a first thermometer (4), a first electric door (3) and a first fast-closing check valve (2) are sequentially arranged on the steam inlet pipeline along the working medium flow direction.

5. The system for switching steam source of steam-driven feedwater pumps adapted to deep peak load regulation according to claim 4 is characterized in that: A second pressure gauge (13), a second thermometer (12), a second fast-closing check valve (11), a second electric door (10), a first flow meter (7) and a first check valve (6) are sequentially arranged on the small machine low-pressure steam inlet pipeline along the working medium flow direction.

6. The system for switching steam source of a steam-driven feedwater pump adapted for deep peak regulation according to claim 5 is characterized in that: A fourth pressure gauge (22), a fourth thermometer (21), a fourth electric door (20), a first regulating valve (19), a second flow meter (18) and a second check valve (17) are sequentially arranged on the steam pipeline for deep peak regulation of the small unit along the flow direction of the working medium.

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