CN211287801U - Small machine steam inlet control device based on application of standby steam source - Google Patents
Small machine steam inlet control device based on application of standby steam source Download PDFInfo
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- CN211287801U CN211287801U CN201922268496.1U CN201922268496U CN211287801U CN 211287801 U CN211287801 U CN 211287801U CN 201922268496 U CN201922268496 U CN 201922268496U CN 211287801 U CN211287801 U CN 211287801U
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Abstract
The utility model relates to a little quick-witted admission controlling means based on use reserve vapour source, include: the system comprises a standby steam source, a steam inlet electric valve, a gas supply pressure adjusting valve, a four-pump and steam supply main pipe pressure measuring device, a small-machine quick closing valve, a small-machine adjusting valve, a small steam turbine, a water feeding pump and corresponding pipelines; the standby steam source is connected with the inlet of the steam inlet electric door through a pipeline; the outlet of the steam inlet electric door is connected with the air supply pressure adjusting door through a pipeline. The utility model has the advantages that: the utility model discloses can be applied to all kinds of large-scale thermal power generating units that have the steam-operated feedwater pump system. The utility model discloses can be under special and accident condition, if when taking place for pump RB, guarantee the vapour quality of supplying of steam-operated water supply system, maintain the water-feeding pump exert oneself normally, avoid the feedwater flow to hang down excessively, reach and guarantee unit safe operation, improve unit operational reliability's purpose.
Description
Technical Field
The utility model relates to a boiler water supply field especially includes little quick-witted admission controlling means based on use reserve vapour source.
Background
The steam-driven feed water pump is used as an important auxiliary machine of the thermal power generating unit, and plays a role in ensuring boiler feed water, and the normal operation of the steam-driven feed water pump has important significance on the safety of unit operation. The main function of the steam feed pump system is to pump water into the boiler for heat exchange, and finally generate superheated steam to drive the steam turbine to do work. The steam-driven feed water pump system generally comprises a steam source, a small quick closing valve, a small regulating valve, a small steam turbine, a feed water pump and related pipelines, and the overall structure of the steam-driven feed water pump system is shown in figure 1. The main working principle and the flow of the steam feed pump are as follows: the steam-driven water-feeding pump adopts the fourth-stage steam extraction of the steam turbine as a steam source, the steam enters the small steam turbine to do work through the small quick closing valve and the small regulating valve, the heat energy of the steam is converted into the rotary mechanical energy of the small steam turbine, and the water-feeding pump is further driven to rotate to supply water to the boiler. In the system, the small-turbine quick closing valve is mainly used for quickly cutting off steam inlet of the small turbine under the conditions of abnormality and accidents of the pump system, so that the safety of the system and equipment is ensured. The small machine regulating valve is used for regulating the rotating speed of the small machine, controlling the steam inlet flow of the small machine according to the instruction, further regulating the rotating speed and the output of the small machine, and achieving the purposes of controlling the water supply flow and meeting the water supply requirement of the boiler. And the steam is expanded in the small machine to do work and then is discharged to the condenser through the steam discharge pipeline.
At present, the steam source of the steam-driven water-feeding pump is mostly taken from the fourth section of the steam turbine for steam extraction, and the steam supply quantity and the main steam supply parameters can ensure the normal operation of the small steam turbine under normal conditions. However, when the unit generates the RB, especially when the pump generates the RB, the load is rapidly reduced, and the requirement for water supply output cannot be met only by adopting four-stage steam extraction, which may seriously threaten the operation safety of the water supply system. From the current grasped condition, when the feed pump RB occurs in the subcritical unit, the operation safety of a unit feed system is difficult to guarantee only by operating a single-side steam pump on the premise of not starting the electric feed pump, and the unit is very easy to stop. The main reason for this situation is the rapid decrease of the steam supply quality of the small steam turbine steam source under the RB condition. When RB occurs, the unit usually sends an instruction to directly shut down a plurality of powder making systems in order to ensure the operation safety of the unit, so that the combustion intensity in the hearth of the boiler is rapidly reduced. Along with the rapid weakening of combustion, the steam production and the unit load of a boiler are inevitably reduced, the throttle of a steam turbine in the RB process is also reduced, the key parameters such as the pressure, the temperature and the steam extraction quantity of the four-section steam extraction of the unit are continuously reduced in the RB process under the combined action of various factors, the energy quality and the steam supply quantity of the steam supply of the small steam turbine are rapidly reduced under the condition, and the normal water outlet and the boiler water supply flow of a steam-driven water supply pump are threatened finally, so that the operation safety of the unit is influenced. Therefore, the reduction of the steam extraction energy in the RB process is the main reason that the pumping force of the running water supply pump is limited and the running safety of a water supply system and a unit is influenced, and the reduction is also an important defect and a short board which threaten the safe running of the unit in the current steam-driven water supply system with single steam source for steam supply.
SUMMERY OF THE UTILITY MODEL
The utility model aims at overcoming the not enough among the prior art, provide the little quick-witted admission controlling means based on using reserve vapour source.
The small machine steam inlet control device based on the application standby steam source comprises: the system comprises a standby steam source, a steam inlet electric valve, a gas supply pressure adjusting valve, a four-pump and steam supply main pipe pressure measuring device, a small-machine quick closing valve, a small-machine adjusting valve, a small steam turbine, a water feeding pump and corresponding pipelines;
the standby steam source is connected with the inlet of the steam inlet electric door through a pipeline; the outlet of the steam inlet electric door is connected with the air supply pressure adjusting door through a pipeline; a pipeline between the four-pump and the inlet of the small quick closing valve is sequentially provided with a gas supply pressure adjusting door and a gas supply main pipe pressure measuring device in the sequence of the four-pump, the gas supply pressure adjusting door, the gas supply main pipe pressure measuring device and the small quick closing valve; the outlet of the small quick closing valve is connected with the inlet of the small adjusting valve through a pipeline; the outlet of the small turbine regulating valve is connected with the inlet of the small turbine through a pipeline; the small turbine is connected with a feed pump.
Preferably, the standby steam source is cold secondary steam or auxiliary steam taken from a unit, and can supply steam with stable quality and meeting the requirements of parameters.
Preferably, under the normal working condition, the steam inlet electric valve and the air supply pressure adjusting valve are both closed.
The utility model has the advantages that: the utility model discloses can be applied to all kinds of large-scale thermal power generating units that have the steam-operated feedwater pump system. The utility model discloses can be under special and accident condition, if when taking place for pump RB, guarantee the vapour quality of supplying of steam-operated water supply system, maintain the water-feeding pump exert oneself normally, avoid the feedwater flow to hang down excessively, reach and guarantee unit safe operation, improve unit operational reliability's purpose.
Drawings
FIG. 1 is a block diagram of a steam feed pump;
FIG. 2 is a block diagram of a small machine steam admission control device based on the application of a backup steam source;
FIG. 3 is a logic diagram of a backup steam source pressure regulator valve control;
FIG. 4 is a flow chart of the steam admission control of the small engine under the working condition of a feed pump RB.
Description of reference numerals: the system comprises a small machine air source 1, a small machine quick-closing valve 2, a small machine adjusting valve 3, a small steam turbine 4, a water feeding pump 5, a steam inlet electric valve 6, a gas supply pressure adjusting valve 7, a standby steam source 8, a four-pump 9 and a steam supply main pipe pressure measuring device 10.
Detailed Description
The present invention will be further described with reference to the following examples. The following description of the embodiments is merely provided to aid in understanding the invention. It should be noted that, for those skilled in the art, the present invention can be modified in several ways without departing from the principle of the present invention, and these modifications and modifications also fall into the protection scope of the claims of the present invention.
In order to improve the reliability of generating set operation, promote the security of unit operation under the RB operating mode, especially for the security of unit operation when pump RB single steam pump moves, the utility model provides a little quick-witted admission controlling means based on using reserve vapour source when the steam supply quality and the unable demand that satisfies of flow of main vapour source, utilizes reserve vapour source to supply, and the main parameter that maintains the steam supply is normal, guarantees exerting oneself of little machine and water supply system's normal operating, improves the security and the reliability of the whole operation of thermal power unit under the accident condition.
The main structure of the utility model is shown in figure 2. The control device comprises a standby steam source 8, a steam inlet electric valve 6, a gas supply pressure adjusting valve 7, a four-pump 9, a steam supply main pipe pressure measuring device 10, a small-machine quick closing valve 2, a small-machine adjusting valve 3, a small steam turbine 4, a water feeding pump 5 and corresponding pipelines; the standby steam source 8 can be selected from cold secondary steam, auxiliary steam and other steam sources with stable steam supply quality. The steam supply main pipe pressure measuring device 10 is positioned in front of the small engine quick-closing valve 2 and is used for monitoring the pressure of the small engine steam supply main pipe. When the unit normally operates, the small engine supplies steam through the four-pump 9, the small engine regulating valve 3 normally regulates the steam inlet flow of the small engine according to the rotating speed instruction, the water feeding pump 5 is driven to discharge water, and the water feeding requirement is met. When the water supply pump 5 pumps RB, the load of the main engine is reduced rapidly, the steam extraction amount of the fourth pump 9 is reduced, the steam supply pressure is reduced continuously, the output of the small engine is reduced finally, and the stability of the water supply flow is further influenced. At this time, the standby steam source 8 must be put into as soon as possible to ensure the normal output of the small machine (the rotating speed instruction here is the control instruction of the small machine, and the source of the small machine instruction is that the power grid dispatching sends an AGC instruction (automatic power generation control instruction) to the generator set, namely the power generation load instruction of the generator set, the load instruction generates a boiler instruction, the boiler instruction generates a fuel instruction, an air supply instruction and a water supply instruction, wherein the water supply instruction generates the rotating speed instruction of the small machine regulating valve).
When RB of the water supply pump 5 occurs, firstly, the steam inlet electric door 6 is directly opened through the interlocking logic, and the standby steam source 8 is put into a hot standby state. Along with the reduction of the load, when the pressure of the steam supply of the four-pump 9 is reduced to a certain degree, the air supply pressure adjusting valve 7 of the standby steam source 8 is gradually opened to adjust the pressure of the steam supply main pipe. The pressure setting value parameter of the air supply pressure adjusting door 7 is determined according to the steam inlet parameter requirement of the small machine. In order to prevent the small-sized adjusting door 3 from coupling and oscillating with the pressure adjustment of the steam inlet electric door 6, the pressure controller is provided with a certain dead zone. Therefore, the steam supply pressure of the small machine can be ensured to be always in a proper level, and the output of the steam-driven water supply pump under the accident condition is further ensured.
When the small machine trips or is in a non-steam pump RB working condition, in order to avoid the influence of the standby steam supply on the safety of the small machine, the steam inlet electric door 6 on the standby steam supply pipeline is closed in a linkage mode, and the valve position adjusting instruction of the regulating door is 0.
The control method of the small-sized machine steam inlet control device based on the application of the standby steam source has the flow chart shown in fig. 4, and includes but is not limited to the following steps:
1) additionally adding a set of spare steam source steam supply and adjusting device on a steam supply system of the original steam-driven water supply pump; the additionally added standby steam source steam supply and adjustment device comprises a standby steam source 8, a steam inlet electric valve 6, a steam supply pressure adjustment valve 7, a steam supply main pipe pressure measurement device 10 and corresponding pipelines;
2) under the normal working condition, the small machine is normally supplied with steam by using the four-pump 9;
3) when abnormal conditions occur, the water feeding pump 5 trips, the water feeding pump 5 triggers the RB working condition, the steam inlet electric door 6 is opened in a linkage mode, and the standby steam source 8 is put into a hot standby state;
4) the control system monitors the steam inlet pressure of the small steam turbine 4 in real time according to the measurement result of the steam supply main pipe pressure measurement device 10 to obtain a pressure measurement result;
5) when RB load reduction occurs, judging the change of the steam supply pressure of the four-pump 9 according to the pressure measurement result in the step 4), if the steam supply pressure of the four-pump 9 is reduced, the pressure of a steam supply main pipe is continuously reduced, gradually opening a gas supply pressure adjusting door 7 according to a pressure control algorithm, and adjusting the pressure of the steam supply main pipe according to the pressure measurement result in the step 4); the output of the small engine is maintained, and the water supply flow is ensured;
6) when the unit operates normally or the small unit trips, the steam inlet electric door 6 and the air supply pressure adjusting door 7 are closed through interlocking logic.
Step 5) the pressure control algorithm is shown in fig. 3, the pressure control algorithm takes the set value of the air supply pressure and the actual air supply pressure as two inputs, and the deviation between the actual air supply pressure and the set value of the air supply pressure is calculated; the down-link is provided with a dead zone function f (X), the down-link is provided with f (X) for increasing a control dead zone, f (X) is a custom broken line function, X is an input, Y is an output, each piece of large DCS control system software has the function, a plurality of end points are arranged in the function block, two end points independently form a section of linear function, each section of linear function is connected to serve as f (X) an integral function, for example, if two end points are set to be (X, Y) corresponding to (0,0) - (100 ), a function equation is Y ═ X. Setting two end points as (a, 0) - (100 ), wherein the function equation is that Y is 100 (x-a)/(100-a), a is a set dead zone, namely when the input is equal to or less than a, the output Y is 0, namely when the input is less than or equal to the set dead zone, the input deviation of the downstream PID regulator of f (x) is 0, and no operation is carried out; a switching function block is also arranged behind the downlink PID regulator, and is used for performing phase comparison between the RB signal of the water feed pump 5 and the running signal of the water feed pump 5 at the side, namely when both signals are met, the judgment condition is satisfied, and the output is TRUE which represents digital quantity '1'; the NO end of the switching block is input and is digital 0, the YES end of the switching block is output by a PID regulator, when the judgment condition is satisfied, the output of the switching block is YES end, otherwise, the output of the switching block is NO end, the logic in the figure means that under the condition that the RB signal of the water feeding pump 5 and the running signal of the water feeding pump 5 at the side are triggered simultaneously, the gas supply pressure regulating valve 7 adopts PID operation to control the regulating valve instruction, otherwise, the regulating valve instruction is 0, and the gas supply pressure regulating valve 7 is closed.
Claims (3)
1. A small machine steam inlet control device based on an application standby steam source is characterized by comprising: the system comprises a standby steam source (8), a steam inlet electric valve (6), a gas supply pressure adjusting valve (7), a four-pump (9), a steam supply main pipe pressure measuring device (10), a small-machine quick closing valve (2), a small-machine adjusting valve (3), a small steam turbine (4), a water feed pump (5) and corresponding pipelines;
the standby steam source (8) is connected with the inlet of the steam inlet electric door (6) through a pipeline; the outlet of the steam inlet electric door (6) is connected with the air supply pressure adjusting door (7) through a pipeline; a pipeline between the four-pump (9) and the inlet of the small engine quick-closing valve (2) is sequentially provided with an air supply pressure adjusting door (7) and a steam supply main pipe pressure measuring device (10) in the order of the four-pump (9), the air supply pressure adjusting door (7), the steam supply main pipe pressure measuring device (10) and the small engine quick-closing valve (2); the outlet of the small-machine quick-closing valve (2) is connected with the inlet of the small-machine regulating valve (3) through a pipeline; the outlet of the small turbine regulating valve (3) is connected with the inlet of the small turbine (4) through a pipeline; the small turbine (4) is connected with a water feeding pump (5).
2. The small-sized machine steam inlet control device based on the application of the standby steam source according to claim 1, characterized in that: the standby steam source (8) is taken from cold secondary steam or auxiliary steam of the unit.
3. The small-sized machine steam inlet control device based on the application of the standby steam source according to claim 1, characterized in that: under normal working conditions, the steam inlet electric door (6) and the air supply pressure adjusting door (7) are both closed.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922268496.1U CN211287801U (en) | 2019-12-17 | 2019-12-17 | Small machine steam inlet control device based on application of standby steam source |
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| CN201922268496.1U CN211287801U (en) | 2019-12-17 | 2019-12-17 | Small machine steam inlet control device based on application of standby steam source |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110985139A (en) * | 2019-12-17 | 2020-04-10 | 浙江浙能技术研究院有限公司 | Small machine steam admission control device and method based on application of standby steam source |
| CN112943387A (en) * | 2021-04-02 | 2021-06-11 | 浙江浙能兰溪发电有限责任公司 | Steam source control method and steam source control device |
-
2019
- 2019-12-17 CN CN201922268496.1U patent/CN211287801U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110985139A (en) * | 2019-12-17 | 2020-04-10 | 浙江浙能技术研究院有限公司 | Small machine steam admission control device and method based on application of standby steam source |
| CN112943387A (en) * | 2021-04-02 | 2021-06-11 | 浙江浙能兰溪发电有限责任公司 | Steam source control method and steam source control device |
| CN112943387B (en) * | 2021-04-02 | 2023-03-21 | 浙江浙能兰溪发电有限责任公司 | Steam source control method and steam source control device |
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