CN111678119A - Boiler wet-state water recovery system under low load of coal-fired unit and working method - Google Patents
Boiler wet-state water recovery system under low load of coal-fired unit and working method Download PDFInfo
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- CN111678119A CN111678119A CN202010687328.0A CN202010687328A CN111678119A CN 111678119 A CN111678119 A CN 111678119A CN 202010687328 A CN202010687328 A CN 202010687328A CN 111678119 A CN111678119 A CN 111678119A
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- water
- deaerator
- wet
- coal
- low load
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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
- F22D1/50—Feed-water heaters, i.e. economisers or like preheaters incorporating thermal de-aeration of feed-water
Abstract
The invention discloses a boiler wet water recovery system under low load of a coal-fired unit and a working method thereof.
Description
Technical Field
The invention belongs to the field of energy conservation and emission reduction of a steam turbine, and particularly relates to a boiler wet-state water recovery system under low load of a coal-fired unit and a working method.
Background
With the implementation of energy conservation and emission reduction and the development of clean energy, the deep peak regulation to low-load operation of a coal-fired unit becomes a normal state. When the unit is deeply peaked to 20-30% of rated load, the boiler is changed from dry state to wet state to operate, and the steam-water separator is started. The steam separated by the boiler through the steam-water separator enters the superheater, absorbs the heat released by fuel combustion and turns into superheated steam for further expansion and work; the separated saturated water enters a water storage tank and is discharged into a drainage flash tank or a condenser through a water level overflow regulating valve (a 361 valve for short), and even into a sewage system. Because the water separated by the steam-water separator is saturated water under the water supply pressure, the water belongs to high-quality drainage, and if the water is directly discharged into a condenser or even a sewage system without being recycled, a large amount of mass and heat loss can be caused, and the operation economy of the unit is influenced.
Disclosure of Invention
The invention aims to overcome the defects and provides a boiler wet-state water recovery system and a working method under the low load of a coal-fired unit, which can recover high-quality hydrophobic water generated by a steam-water separator during the wet-state operation of a boiler and improve the operation economy.
In order to achieve the aim, the boiler wet-state water recovery system under the low load of the coal-fired unit comprises a water storage tank and a deaerator, wherein the deaerator is connected with a low-pressure heater and a high-pressure heater;
the water storage tank is used for supplying wet water;
the deaerator is used for heating the condensed water supplied by the low-pressure heater through the wet water and sending the condensed water into the high-pressure heater.
The water storage tank is connected with a condenser.
A first temperature and pressure reducer is arranged between the water storage tank and the condenser.
A water level overflow regulating valve is arranged below the water storage tank.
A second temperature and pressure reducing device is arranged in front of the deaerator.
A water feeding pump is arranged between the deaerator and the high-pressure heater.
A working method of a boiler wet-state water recovery system under low load of a coal-fired unit is characterized in that a low-pressure heater continuously supplies condensed water to a deaerator;
introducing wet water in the water storage tank into a water side inlet of the deaerator to heat condensed water entering the deaerator;
the condensed water heated by the deaerator is sent to a high-pressure heater to be used as feed water.
After the water storage tank is supplied to the deaerator, redundant wet water is discharged into the condenser.
The condensed water heated by the deaerator is sent into the high-pressure heater after being boosted by the water feeding pump.
Compared with the prior art, the invention introduces a part of boiler wet water in the water storage tank into the water side inlet of the deaerator to replace the original four-section steam extraction heating condensed water, recycles the quality and heat of the part of wet water, and can stop the low-pressure heater when the wet water is large, so as to heat the condensed water by using more wet water, realize the maximization of the quality and heat utilization and greatly improve the operation economy of the unit under the conditions of deep peak regulation and low load.
The method comprises the steps that wet water in a water storage tank is introduced into a water side inlet of a deaerator and used for heating condensed water entering the deaerator, the wet water in the water storage tank is introduced into the water side inlet of the deaerator and used for heating the condensed water entering the deaerator, and the condensed water heated by the deaerator is sent into a high-pressure heater to serve as feed water. The maximization of quality and heat utilization can be realized, and the running economy of the unit under deep peak regulation and low load is greatly improved.
Drawings
FIG. 1 is a block diagram of the system of the present invention;
wherein, 1, water storage tank, 2, oxygen-eliminating device, 3, low pressure feed water heater, 4, high pressure feed water heater, 5, condenser, 6, first temperature and pressure reduction ware, 7, water level overflow governing valve, 8, second temperature and pressure reduction ware, 9, feed water pump.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
Referring to fig. 1, the boiler wet water recovery system under the low load of the coal-fired unit comprises a water storage tank 1 and a deaerator 2, wherein the deaerator 2 is connected with a low-pressure heater 3 and a high-pressure heater 4, the water storage tank 1 is connected with the water side of the deaerator 2, the low-pressure heater 3 is connected with a condensate system, the high-pressure heater 4 is connected with a water supply system, and a water supply pump 9 is arranged between the deaerator 2 and the high-pressure heater 4; the water storage tank 1 is used for supplying wet water; the deaerator 2 is used for heating the condensed water supplied by the low pressure heater 3 by the wet water and sending the heated condensed water into the high pressure heater 4. A water level overflow regulating valve 7 is arranged below the water storage tank 1, and the water storage tank 1 is connected with a condenser 5. A first temperature and pressure reducer 6 is arranged between the water storage tank 1 and the condenser 5. A second temperature and pressure reducing device 8 is arranged in front of the deaerator 2.
A working method of a boiler wet-state water recovery system of a coal-fired unit under low load comprises the following specific steps:
the low-pressure heater 3 continuously supplies condensed water to the deaerator 2; the wet water in the water storage tank 1 is introduced into a water side inlet of the deaerator 2 to heat the condensed water entering the deaerator 2, and redundant wet water is discharged into the condenser 5. The condensed water heated by the deaerator 2 is sent to the high-pressure heater 4 as feed water after being boosted by the feed water pump 9.
After the optimization of the invention, the steam extraction amount of the four-section steam inlet of the deaerator 2 is basically 0, and all the water is replaced by the heat of high-quality wet water in the water storage tank, the water flows through the second temperature and pressure reducing device 8 and then becomes the operating pressure of the deaerator 2, and enters the water side inlet of the deaerator 2 to heat the condensed water entering the deaerator; the wet water of the boiler which can not be absorbed by the deaerator in the water storage tank 1 is discharged into the condenser 5 after passing through the first temperature and pressure reducing device 6. In addition, when the wet water quantity of the boiler is larger, the low-pressure heater 3 is shut down to heat the condensed water by utilizing more high-quality wet water, so that the maximization of the utilization of the quality and the heat is realized, and the running economy of the unit under the deep peak regulation and the low load is greatly improved.
The rated load of a coal-fired steam turbine unit of a certain power plant is 350MW, when the unit is operated with deep peak regulation to 30% of rated load (105 MW), 80t of high-quality wet water (the pressure is 13.4MPa, the temperature is 333.3 ℃) is separated out by a boiler, and the water flows through a temperature and pressure reducer and is directly discharged into a condenser during actual operation. After the invention is transformed, about 40t of wet water is changed into the operating pressure of 0.29MPa of the deaerator through the temperature and pressure reducing device and is led into the water side inlet of the deaerator, and the heat provided by the four-section steam extraction is completely replaced.
The heat balance diagram of the unit after recovery of high-quality wet water under the rated load of 30% is simulated through Ebsilon software. According to calculation, when 80t of high-energy hydrophobic water is completely discharged into a condenser, the heat consumption rate of a unit is about 8860kJ/(kWh), and the reduced coal consumption rate is about 331.9 g/(kWh); after the recovery, about 40t of wet water of the boiler enters a deaerator, the low-pressure heater 3 is shut down, the heat consumption rate of a unit is about 8600kJ/(kWh), the reduced coal consumption rate is about 322.2g/(kWh), and compared with the heat consumption rate when the wet water is discharged into a condenser and is not recycled, the heat consumption rate is reduced by 260kJ/(kWh), the coal consumption rate is reduced by about 9.7g/(kWh), and the reduction range is about 2.92%. Therefore, the heat consumption rate and the coal consumption rate of the unit are greatly reduced under the rated load of 30 percent after the high-quality wet water is recovered and modified, and the operation economy is greatly improved.
Claims (9)
1. A boiler wet-state water recovery system under low load of a coal-fired unit is characterized by comprising a water storage tank (1) and a deaerator (2), wherein the deaerator (2) is connected with a low-pressure heater (3) and a high-pressure heater (4), the water storage tank (1) is connected with the water side of the deaerator (2), the low-pressure heater (3) is connected with a condensed water system, and the high-pressure heater (4) is connected with a water supply system;
the water storage tank (1) is used for supplying wet water;
the deaerator (2) is used for heating the condensed water supplied by the low-pressure heater (3) through wet water and sending the condensed water into the high-pressure heater (4).
2. The system for recovering the wet water of the boiler under the low load of the coal-fired unit according to the claim 1, characterized in that the water storage tank (1) is connected with a condenser (5).
3. The recovery system of wet water of a boiler under low load of a coal-fired unit according to claim 2, characterized in that a first temperature and pressure reducer (6) is arranged between the water storage tank (1) and the condenser (5).
4. The recovery system of wet water of a boiler under low load of a coal-fired unit according to claim 1, characterized in that a water level overflow regulating valve (7) is arranged under the water storage tank (1).
5. The recovery system of boiler wet water under low load of coal-fired unit according to claim 1, characterized in that a second temperature and pressure reducing device (8) is arranged in front of the deaerator (2).
6. The recovery system of wet water of a boiler under low load of a coal-fired unit according to claim 1, characterized in that a feed water pump (9) is arranged between the deaerator (2) and the high-pressure heater (4).
7. The operating method of the boiler wet water recovery system under the low load of the coal-fired unit as claimed in claim 1, characterized in that the low-pressure heater (3) continuously supplies the deaerator (2) with condensed water;
wet water in the water storage tank (1) is introduced into a water side inlet of the deaerator (2) to heat condensed water entering the deaerator (2);
the condensed water heated by the deaerator (2) is sent to the high-pressure heater (4) to be used as feed water.
8. The working method of the boiler wet water recovery system under the low load of the coal-fired unit according to claim 7, characterized in that after the deaerator (2) is supplied to the water storage tank (1), the surplus wet water is discharged into the condenser (5).
9. The operating method of the boiler wet water recovery system under the low load of the coal-fired unit as claimed in claim 7, characterized in that the condensed water heated by the deaerator (2) is sent to the high-pressure heater (4) after being boosted by the feed pump (9).
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010687328.0A CN111678119A (en) | 2020-07-16 | 2020-07-16 | Boiler wet-state water recovery system under low load of coal-fired unit and working method |
| PCT/CN2020/128441 WO2022011903A1 (en) | 2020-07-16 | 2020-11-12 | Boiler wet water recovery system under low load of coal-fired unit and working method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010687328.0A CN111678119A (en) | 2020-07-16 | 2020-07-16 | Boiler wet-state water recovery system under low load of coal-fired unit and working method |
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| CN111678119A true CN111678119A (en) | 2020-09-18 |
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| CN202010687328.0A Pending CN111678119A (en) | 2020-07-16 | 2020-07-16 | Boiler wet-state water recovery system under low load of coal-fired unit and working method |
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| CN (1) | CN111678119A (en) |
| WO (1) | WO2022011903A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112303611A (en) * | 2020-10-30 | 2021-02-02 | 西安热工研究院有限公司 | Direct current furnace high energy water recovery system |
| CN113446649A (en) * | 2021-07-30 | 2021-09-28 | 西安热工研究院有限公司 | Logic control system and method for high-energy water inlet regulating valve in double control modes |
| WO2022011903A1 (en) * | 2020-07-16 | 2022-01-20 | 西安热工研究院有限公司 | Boiler wet water recovery system under low load of coal-fired unit and working method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114738732B (en) * | 2022-03-24 | 2024-04-05 | 青岛畅隆重型装备有限公司 | One-key start-stop system of high-voltage heater and control method thereof |
| CN115899666B (en) * | 2022-10-24 | 2023-12-26 | 华电电力科学研究院有限公司 | Boiler wet water cascade utilization system under deep peak shaving of supercritical coal-fired unit |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10169907A (en) * | 1996-12-06 | 1998-06-26 | Mitsubishi Heavy Ind Ltd | Boiler plant |
| JP2000257806A (en) * | 1999-03-08 | 2000-09-22 | Nippon Steel Corp | Drain recovery system for heat exchanger |
| CN107631288A (en) * | 2017-09-30 | 2018-01-26 | 北京姚魏环保技术有限公司 | A kind of method of fired power generating unit depth peak regulation and backheat energy-conservation |
| CN108870372B (en) * | 2018-06-29 | 2022-01-21 | 山东电力工程咨询院有限公司 | Direct current furnace drainage recovery system and method based on high-low pressure drainage flash tank |
| CN208967776U (en) * | 2018-07-18 | 2019-06-11 | 深能合和电力（河源）有限公司 | A kind of supercritical once-through boiler pipe-line system |
| CN111256192B (en) * | 2020-03-18 | 2024-02-23 | 青岛达能环保设备股份有限公司 | Comprehensive frequency modulation peak regulation system for coal-fired power plant |
| CN111678119A (en) * | 2020-07-16 | 2020-09-18 | 西安热工研究院有限公司 | Boiler wet-state water recovery system under low load of coal-fired unit and working method |
| CN111664435A (en) * | 2020-07-22 | 2020-09-15 | 西安热工研究院有限公司 | Drainage recovery system and method during boiler blowpipe period |
-
2020
- 2020-07-16 CN CN202010687328.0A patent/CN111678119A/en active Pending
- 2020-11-12 WO PCT/CN2020/128441 patent/WO2022011903A1/en active Application Filing
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022011903A1 (en) * | 2020-07-16 | 2022-01-20 | 西安热工研究院有限公司 | Boiler wet water recovery system under low load of coal-fired unit and working method |
| CN112303611A (en) * | 2020-10-30 | 2021-02-02 | 西安热工研究院有限公司 | Direct current furnace high energy water recovery system |
| CN113446649A (en) * | 2021-07-30 | 2021-09-28 | 西安热工研究院有限公司 | Logic control system and method for high-energy water inlet regulating valve in double control modes |
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| WO2022011903A1 (en) | 2022-01-20 |
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