CN111023077A - Drainage system with external cooler for low-pressure heater and control method - Google Patents
Drainage system with external cooler for low-pressure heater and control method Download PDFInfo
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- CN111023077A CN111023077A CN201911336169.3A CN201911336169A CN111023077A CN 111023077 A CN111023077 A CN 111023077A CN 201911336169 A CN201911336169 A CN 201911336169A CN 111023077 A CN111023077 A CN 111023077A
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- pressure heater
- drainage
- stage
- low
- penultimate
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
- F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
- F22D1/32—Feed-water heaters, i.e. economisers or like preheaters arranged to be heated by steam, e.g. bled from turbines
Abstract
The invention discloses a drainage system of a low-pressure heater with an external cooler and a control method thereof, and the drainage system comprises a final-stage low-pressure heater, a penultimate-stage low-pressure heater, a drainage cooler and a condensing device, wherein a final-stage drainage pipeline is communicated with the lower part of the final-stage low-pressure heater, a penultimate-stage drainage pipeline is communicated with the lower part of the penultimate-stage low-pressure heater, the final-stage drainage pipeline and the penultimate-stage drainage pipeline are communicated with the drainage cooler through a communication pipeline, and a drainage regulating valve is communicated between the drainage cooler and the condensing device. The invention has the beneficial effects that: the scheme can regulate and control the drainage on line in real time in the whole process of starting, load rising, variable working condition and stopping of the unit, meets the control requirement of each associated device on drainage, and creates necessary conditions for safe, stable and efficient continuous operation of the unit.
Description
Technical Field
The invention relates to the technical field of power generation of steam turbines, in particular to a drainage system of a low-pressure heater with an external cooler and a control method.
Background
In order to improve the generating efficiency of a steam turbine generator unit, in the steam turbine regenerative systems of thermal power plants and nuclear power plants, a final-stage low-pressure heater and a next-final-stage low-pressure heater are mostly provided with built-in hydrophobic cooling sections or adopt external hydrophobic coolers so as to recover heat in extracted steam condensate as much as possible. Due to the limiting factors in the aspects of structure, operation safety, stability and the like, the adoption of the external drainage cooler gradually tends to improve the safety and stability of unit operation, and meanwhile, the smaller drainage end difference can be realized, and greater potential is provided for the economic efficiency of the unit.
However, in the actual engineering design, the drainage of the last two stages of low-pressure heaters is simultaneously connected to the heat recovery system of the same external drainage cooler, and no good solution is provided for the drainage water level control of each associated heater so as to ensure the safe, stable and efficient continuous operation of the system.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a drainage system of a low-pressure heater with an external cooler and a control method, which are used for reducing drainage end difference and improving the stability and the safety of the system when drainage of last two stages of low-pressure heaters is connected to the same external drainage cooler at the same time.
The invention is realized by the following technical scheme: a drainage system of a low-pressure heater with an external cooler and a control method thereof comprise a final-stage low-pressure heater, a penultimate-stage low-pressure heater, a drainage cooler and a condensing device, wherein a final-stage drainage pipeline is communicated with the lower part of the final-stage low-pressure heater, a penultimate-stage drainage pipeline is communicated with the lower part of the penultimate-stage low-pressure heater, the final-stage drainage pipeline and the penultimate-stage drainage pipeline are communicated with the drainage cooler through a communication pipeline, and a drainage regulating valve is communicated between the drainage cooler and the condensing device.
Further, in order to better realize the invention, the hydrophobic adjusting valve adopts a power control valve.
Further, in order to better realize the invention, a liquid level sensor is arranged in the final stage drainage pipeline or the final stage low-pressure heater.
Further, in order to better realize the invention, a liquid level sensor is arranged in the penultimate drainage pipeline.
Further, in order to better realize the invention, the final stage low-pressure heater and the next final stage low-pressure heater are arranged at a higher height than the hydrophobic cooler.
A drain control method for a low-pressure heater with an external cooler comprises the steps of starting a last-stage low-pressure heater and a penultimate-stage low-pressure heater to enable the last-stage low-pressure heater and the penultimate-stage low-pressure heater to respectively drain water and enable the drain water to enter the drain cooler through a communicating pipeline, forming a last-stage drain liquid level in a last-stage drain pipeline, forming a penultimate-stage drain liquid level in a penultimate-stage drain pipeline, gradually raising the last-stage drain liquid level or the penultimate-stage drain liquid level until one of the last-stage drain liquid level and the penultimate-stage drain liquid level reaches a set target liquid level, starting a drain regulating valve to enable the liquid level of the drain liquid level to be stabilized at the target liquid level, enabling the height difference between the drain liquid level of.
Further, in order to better realize the invention, before the final stage low-pressure heater and the next final stage low-pressure heater are started, the interior of the hydrophobic system can be vacuumized.
The beneficial effect that this scheme obtained is:
the scheme can regulate and control the drainage on line in real time in the whole process of starting, load rising, variable working condition and stopping of the unit, meets the requirements of each associated device on drainage control, and creates necessary conditions for safe, stable and efficient continuous operation of the unit.
Drawings
FIG. 1 is a schematic diagram of the structure of a hydrophobic system;
11-final-stage low-pressure heater, 111-final-stage drain pipeline, 12-penultimate-stage low-pressure heater, 121-penultimate-stage drain pipeline, 13-drain cooler, 131-communicating pipeline, 14-condensing equipment and 15-drain regulating valve.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
Example 1:
as shown in fig. 1, in this embodiment, a low-pressure heater drain system with an external cooler and a control method thereof include a final-stage low-pressure heater 11, a next-final-stage low-pressure heater 12, a drain cooler 13, and a condensing device 14, a final-stage drain pipeline 111 is communicated below the final-stage low-pressure heater 11, a next-final-stage drain pipeline 121 is communicated below the next-final-stage low-pressure heater 12, the final-stage drain pipeline 111 and the next-final-stage drain pipeline 121 are communicated with the drain cooler 13 through a communication pipeline 131, and a drain regulating valve 15 is communicated between the drain cooler 13 and the condensing device 14.
Before the unit is started, the interior of the system can be vacuumized, so that the interiors of the final-stage low-pressure heater 11, the next-final-stage low-pressure heater 12, the drain cooler 13 and the condensing equipment 14 are in a vacuum state, and the internal pressures of the final-stage low-pressure heater 11, the next-final-stage low-pressure heater 12, the drain cooler 13 and the condensing equipment 14 are the same.
When the unit is started and the load is increased, the internal pressure of the final-stage low-pressure heater 11 and the next final-stage low-pressure heater 12 is gradually increased, and the pressure in each device forms the following relationship: the penultimate low-pressure heater 12> the final-stage low-pressure heater 11> the condenser 14, and the pressure difference between the devices increases with the increase of the load.
At this time, the condensed drain water of the last stage low-pressure heater 11 is discharged into the drain cooler 13 through the last stage drain line 111, and the condensed drain water of the penultimate stage low-pressure heater 12 is discharged into the drain cooler 13 through the penultimate stage drain line 121.
With the trap valve 15 closed, the entire trap cooler 13 and trap line will be filled with trap water gradually.
Along with the accumulation of the drainage, the liquid level of the drainage can continuously rise until reaching the preset target liquid level, the drainage regulating valve 15 is opened and automatically regulated to maintain the drainage liquid level to be stable at the set height, and the whole system reaches a stable operation state.
The target liquid level may be set in the last low-pressure heater 11 or on the last drain line 111, or may be set in the next-to-last low-pressure heater 12 or the next-to-last drain line 121.
When the load of the unit changes, the pressure difference between the final-stage low-pressure heater 11 and the next-final-stage low-pressure heater 12 changes, at this time, the opening degree of the drain regulating valve 15 is automatically adjusted through the control system to maintain the height of the original regulating target liquid level unchanged, the height of the drain liquid level of the other low-pressure heater changes along with the change of the pressure difference in a controllable height range, and the height difference between the drain liquid level of the other low-pressure heater and the target liquid level depends on the pressure difference between the final-stage low-pressure heater 11 and the next-final-stage low-.
When the unit is unloaded until the unit is shut down, the pressure difference between the final-stage low-pressure heater 11 and the penultimate-stage low-pressure heater 12 is gradually reduced, the height difference of the drainage liquid level is also gradually reduced until the pressure difference disappears, the drainage liquid level is stabilized at the originally set target liquid level height, and the drainage regulating valve 15 is almost closed at the moment; when the unit is completely free of steam, the drain water is not discharged from the final-stage low-pressure heater 11 and the penultimate-stage low-pressure heater 12, the internal pressures of the final-stage low-pressure heater 11, the penultimate-stage low-pressure heater 12 and the condenser 14 are the same, and the drain regulating valve 15 is completely closed.
According to the scheme, a preset target liquid level is used as a reference standard, when the load of the unit changes, the pressure inside the final-stage low-pressure heater 11 and the pressure inside the secondary-stage low-pressure heater 12 change, the drainage flow of the two low-pressure heaters also change, so that the height position of the drainage liquid level deviates from an original set value, and at the moment, the drainage liquid level is regulated and controlled to be restored and maintained at an original set height value by controlling the opening degree of the drainage regulating valve 15. Due to the pressure balance principle of the communicating pipe, when the height of the drainage liquid level of the target low-pressure heater is stabilized at the set value, the height of the drainage liquid level of the other low-pressure heater is naturally formed according to the pressure difference between the two low-pressure heaters and is within a safe and controllable range, so that the safety and the stability of the system are improved.
Example 2:
on the basis of the above embodiments, in this embodiment, the drain control valve 15 is a power control valve, which is beneficial to realizing the function of remote automatic control. For example, a pneumatic, electric, or hydraulic control valve.
In this embodiment, a liquid level sensor is disposed in the final stage drain pipe 111 or the final stage low pressure heater 11.
In this embodiment, a liquid level sensor is disposed in the penultimate drain pipe 121 or the penultimate low-pressure heater 12.
The liquid level sensor can be used for monitoring the height change of the drainage liquid level of the last-stage low-pressure heater or the drainage liquid level of the penultimate low-pressure heater in real time, so that the liquid level sensor is connected with a control system, the change information of the liquid level can be conveniently and timely received and processed, and the safety performance of the system can be improved.
The last stage drain pipeline 111 and the second last stage drain pipeline 121 are arranged in a continuous slope releasing manner, and no ascending section is required; the final stage low pressure heater 11 and the penultimate stage low pressure heater 12 should be arranged at a height higher than the drain cooler 13. Thereby facilitating the normal operation of the system function.
In this embodiment, other undescribed contents are the same as those in the above embodiment, and thus are not described again.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (7)
1. The utility model provides a take low pressure heater drainage system of external cooler which characterized in that: the device comprises a final-stage low-pressure heater (11), a penultimate-stage low-pressure heater (12), a drainage cooler (13) and a condensing device (14), wherein a final-stage drainage pipeline (111) is communicated with the lower part of the final-stage low-pressure heater (11), a penultimate-stage drainage pipeline (121) is communicated with the lower part of the penultimate-stage low-pressure heater (12), the final-stage drainage pipeline (111) and the penultimate-stage drainage pipeline (121) are communicated with the drainage cooler (13) through a communicating pipeline (131), and a drainage regulating valve (15) is communicated between the drainage cooler (13) and the condensing device (14).
2. The drain system of claim 1, wherein the drain system comprises: the drain control valve (15) is a power control valve capable of receiving a control system signal.
3. The drain system of claim 1, wherein the drain system comprises: and a liquid level sensor is arranged in the final stage drainage pipeline (111) or the final stage low-pressure heater (11).
4. The drain system of claim 1, wherein the drain system comprises: and a liquid level sensor is arranged in the penultimate drainage pipeline (121) or the penultimate low-pressure heater (12).
5. The drainage control method for the low-pressure heater with the external cooler as claimed in claim 1, wherein: the arrangement height of the final stage low-pressure heater (11) and the next final stage low-pressure heater (12) is higher than that of the hydrophobic cooler (13).
6. A drainage control method for a low-pressure heater with an external cooler is characterized by comprising the following steps: starting the final stage low-pressure heater (11) and the penultimate stage low-pressure heater (12) in the system of any one of claims 1 to 5, leading the final stage low-pressure heater (11) and the penultimate stage low-pressure heater (12) to respectively generate water drainage and lead the water drainage to enter the water drainage cooler (13) through the communication pipeline (131), forming a final stage water drainage liquid level in the final stage water drainage pipeline (111), forming a penultimate stage water drainage liquid level in the penultimate stage water drainage pipeline (121), leading the final stage water drainage liquid level or the penultimate stage water drainage liquid level to gradually rise until one of the final stage water drainage liquid level or the penultimate stage water drainage liquid level reaches a set target liquid level, opening the water drainage regulating valve (15) to lead the water drainage liquid level to be stabilized at the target liquid level, wherein the height difference between the water drainage liquid level of the final stage low-pressure heater (11) and the penultimate, and automatically varies with the pressure difference.
7. The drainage control method for the low-pressure heater with the external cooler as claimed in claim 6, characterized in that: before the final low-pressure heater (11) and the penultimate low-pressure heater (12) are activated, a vacuum can be drawn inside the system of claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911336169.3A CN111023077A (en) | 2019-12-23 | 2019-12-23 | Drainage system with external cooler for low-pressure heater and control method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911336169.3A CN111023077A (en) | 2019-12-23 | 2019-12-23 | Drainage system with external cooler for low-pressure heater and control method |
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| CN111023077A true CN111023077A (en) | 2020-04-17 |
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| CN201911336169.3A Pending CN111023077A (en) | 2019-12-23 | 2019-12-23 | Drainage system with external cooler for low-pressure heater and control method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112594676A (en) * | 2020-11-30 | 2021-04-02 | 磐石重工(青岛)股份有限公司 | Drainage liquid level measurement and control device for high-low pressure heater |
| CN114370307A (en) * | 2021-12-15 | 2022-04-19 | 东方电气集团东方汽轮机有限公司 | Drainage system and drainage method for high-pressure steam guide pipe of steam turbine |
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| CN101737310A (en) * | 2009-12-25 | 2010-06-16 | 东南大学 | Method for measuring and calculating pump efficiency based on soft flow measurement for drainage pump |
| CN103836608A (en) * | 2014-03-10 | 2014-06-04 | 中国电力工程顾问集团华东电力设计院 | Regenerative system of low-pressure drain water cooler |
| CN203797629U (en) * | 2014-03-10 | 2014-08-27 | 中国电力工程顾问集团华东电力设计院 | Low-pressure drain cooler regenerative system and generator set |
| CN205878122U (en) * | 2016-07-26 | 2017-01-11 | 中国大唐集团科学技术研究院有限公司华东分公司 | Condensate water cleaning system |
| CN208817456U (en) * | 2018-08-31 | 2019-05-03 | 中国电建集团河南省电力勘测设计院有限公司 | A kind of final stage low-pressure heater draining system of self-balancing water seal type |
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2019
- 2019-12-23 CN CN201911336169.3A patent/CN111023077A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101737310A (en) * | 2009-12-25 | 2010-06-16 | 东南大学 | Method for measuring and calculating pump efficiency based on soft flow measurement for drainage pump |
| CN103836608A (en) * | 2014-03-10 | 2014-06-04 | 中国电力工程顾问集团华东电力设计院 | Regenerative system of low-pressure drain water cooler |
| CN203797629U (en) * | 2014-03-10 | 2014-08-27 | 中国电力工程顾问集团华东电力设计院 | Low-pressure drain cooler regenerative system and generator set |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112594676A (en) * | 2020-11-30 | 2021-04-02 | 磐石重工(青岛)股份有限公司 | Drainage liquid level measurement and control device for high-low pressure heater |
| CN114370307A (en) * | 2021-12-15 | 2022-04-19 | 东方电气集团东方汽轮机有限公司 | Drainage system and drainage method for high-pressure steam guide pipe of steam turbine |
| CN114370307B (en) * | 2021-12-15 | 2023-07-14 | 东方电气集团东方汽轮机有限公司 | Steam turbine high-pressure steam guide pipe drainage system and drainage method |
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Application publication date: 20200417 |
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