CN111964028A - Thermal power generating unit high-quality working medium recycling system and working method - Google Patents
Thermal power generating unit high-quality working medium recycling system and working method Download PDFInfo
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- CN111964028A CN111964028A CN202010864942.XA CN202010864942A CN111964028A CN 111964028 A CN111964028 A CN 111964028A CN 202010864942 A CN202010864942 A CN 202010864942A CN 111964028 A CN111964028 A CN 111964028A
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- water
- saturated
- deaerator
- pressure
- thermal power
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- 238000004064 recycling Methods 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 title claims abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 123
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 70
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- 238000000605 extraction Methods 0.000 claims abstract description 4
- 230000002209 hydrophobic effect Effects 0.000 claims description 13
- 238000011084 recovery Methods 0.000 claims description 5
- 230000001105 regulatory effect Effects 0.000 claims description 4
- 125000004122 cyclic group Chemical group 0.000 claims description 2
- 238000004891 communication Methods 0.000 claims 1
- 238000011017 operating method Methods 0.000 claims 1
- 239000003245 coal Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B3/00—Other methods of steam generation; Steam boilers not provided for in other groups of this subclass
- F22B3/04—Other methods of steam generation; Steam boilers not provided for in other groups of this subclass by drop in pressure of high-pressure hot water within pressure- reducing chambers, e.g. in accumulators
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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 high-quality working medium recycling system and a working method of a thermal power generating unit. After the pressure of the saturated steam and the saturated water is reduced, the saturated steam is introduced into the steam side of a deaerator to replace four-section steam extraction to heat the condensed water; the saturated water is introduced into the water side of the deaerator, the condensed water is further heated, the heat is recovered to the maximum extent, when the high-energy water drainage amount is large, the low-pressure heater is stopped, more saturated steam and saturated water are used for heating the condensed water, the maximization of energy utilization is realized, and the operation economy of the unit under deep peak regulation and low load is greatly improved.
Description
Technical Field
The invention belongs to the technical field of operation of steam turbines, and particularly relates to a high-quality working medium recycling system and a working method of a thermal power generating unit.
Background
With the promotion of energy conservation and emission reduction and the development of new energy, the operation from deep peak regulation to low load of the thermal power generating unit becomes a normal state. When the unit is deeply peaked to 20% of rated load, the boiler is switched from dry state to wet state for operation, 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 is changed into superheated steam for further expansion to do work; the separated saturated water enters a water storage tank and is directly discharged into a drainage flash tank or a condenser through a water level overflow regulating valve (called as '361 valve' for short). Because the water separated by the steam-water separator is saturated water under the water supply pressure, the water belongs to high-energy hydrophobic water, if the water is not recycled, a large amount of heat loss is caused, and the operation economy is reduced.
Disclosure of Invention
The invention aims to overcome the defects and provides a high-quality working medium recycling system and a working method for a thermal power generating unit, which can recover high-energy drainage generated by a steam-water separator during wet operation of a boiler and improve the operation economy.
In order to achieve the purpose, the high-quality working medium recycling system of the thermal power generating unit comprises a water storage tank, wherein the water storage tank is connected with a flash tank, the flash tank is connected with a deaerator, the deaerator is connected with a low-pressure heater and a high-pressure heater, the steam side of saturated steam of the flash tank, which is introduced into the deaerator, is used for heating condensed water entering the deaerator, and the water side of the saturated water of the flash tank, which is introduced into the deaerator, is used for continuously heating the condensed water entering the deaerat.
A water feeding pump is arranged between the deaerator and the high-pressure heater.
A water level overflow regulating valve is arranged between the water storage tank and the flash tank.
A saturated steam pressure reducing valve is arranged on a saturated steam pipeline between the flash tank and the deaerator.
A saturated water pressure reducing valve is arranged on a saturated water pipeline between the flash tank and the deaerator.
The condensed water flows through the low pressure heater and the feed water flows through the high pressure heater.
And the drain water of the high-pressure heater is introduced into the condenser.
A working method of a thermal power generating unit high-quality working medium recycling system comprises the following steps:
step one, introducing high-energy hydrophobic water into a flash tank by a water storage tank to generate saturated steam and saturated water;
step two, the saturated steam of the flash tank is merged into the deaerator to provide operating pressure for the deaerator, and the saturated water of the flash tank is introduced into the water side of the deaerator to heat the condensed water in the deaerator;
and step three, feeding the heated condensed water into a high-pressure heater, and discharging the condensed water by the high-pressure heater for drainage.
And when the drainage pressure of the high-pressure heater is lower than the operating pressure of the deaerator, connecting the drainage of the high-pressure heater to the condenser.
Compared with the prior art, the invention adds a flash tank, and introduces the part of high-energy hydrophobic water into the flash tank to generate saturated steam and saturated water under certain pressure. After the pressure of the saturated steam and the saturated water is reduced, the saturated steam is introduced into the steam side of a deaerator to replace four-section steam extraction to heat the condensed water; the saturated water is introduced into the water side of the deaerator, the condensed water is further heated, the heat is recovered to the maximum extent, when the high-energy water drainage amount is large, the low-pressure heater is stopped, more saturated steam and saturated water are used for heating the condensed water, the maximization of energy utilization is realized, and the operation 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;
FIG. 2 is a graph of the heat balance of the high energy hydrophobic recovery in the examples;
the system comprises a flash tank 1, a flash tank 2, a water storage tank 3, a deaerator 4, a low-pressure heater 5, a high-pressure heater 6, a saturated steam pressure reducing valve 7, a saturated water pressure reducing valve 8, a condenser 9, a water level overflow regulating valve 10 and a water feeding pump.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
Referring to fig. 1, a thermal power generating unit high-quality working medium cyclic utilization system, including water storage tank 2, water storage tank 2 connects flash tank 1, be provided with water level overflow governing valve 9 between water storage tank 2 and flash tank 1, flash tank 1 connects oxygen-eliminating device 3, oxygen-eliminating device 3 connects low pressure feed water heater 4 and high pressure feed water heater 5, be provided with water feed pump 10 between oxygen-eliminating device 3 and high pressure feed water heater 5, the saturated steam of flash tank 1 lets in the vapour side of oxygen-eliminating device 3 and is used for heating the condensate that gets into oxygen-eliminating device 3, the saturated water of flash tank 1 lets in the water side of oxygen-eliminating device 3 and continues to heat the condensate that gets into oxygen-. The low-pressure heater 4 is connected with the deaerator 3, and condensed water of the low-pressure heater 4 is sent into the high-pressure heater 5 after being boosted by the deaerator 3 through the water feeding pump. The low pressure heater 4 is connected with condensed water, and the high pressure heater 5 is connected with feed water. The drain water of the high-pressure heater 5 is introduced into a condenser 8. A saturated steam pressure reducing valve 6 is arranged on a saturated steam pipeline between the flash tank 1 and the deaerator 3. A saturated water pressure reducing valve 7 is arranged on a saturated water pipeline between the flash tank 1 and the deaerator 3.
Referring to fig. 1, a working method of a high-quality working medium recycling system of a thermal power generating unit includes the following steps:
step one, introducing high-energy hydrophobic water into a flash tank 1 by a water storage tank 2 to generate saturated steam and saturated water;
step two, the saturated steam of the flash tank 1 is merged into the deaerator 3 to provide operating pressure for the deaerator 3, and the saturated water of the flash tank 1 is introduced into the water side of the deaerator 3 to heat the condensed water in the deaerator 3;
and step three, feeding the heated condensed water into a high-pressure heater 5, and discharging the condensed water by the high-pressure heater 5 for drainage.
Passing a certain amount of high-energy hydrophobic water through a flash tank (pressure P)0) The resulting saturated steam and saturated water flow are also constant. Assuming that the flow and specific enthalpy of high-energy hydrophobic are Q respectivelyssAnd hssThe pressure of saturated steam and saturated water is P0Then the specific enthalpy can be determined as hbhqAnd hbhsFlow rate Q of saturated steam and saturated waterbhqAnd QbhsCan be obtained by the following two formulas:
Qbhq+Qbhs＝Qss (1)
Qbhq×hbhq+Qbhs×hbhs＝Qss×hss (2)
after the invention is optimized, the steam inlet of the deaerator is changed from four-stage steam extraction into saturated steam which is generated by high-energy hydrophobic passing through the flash tank, the deaerator operates at constant pressure, and the operating pressure is the pressure P after the saturated steam is decompressed1. At the moment, the pressure of the high-pressure normal drainage No. 3 is lower than the operating pressure of the deaerator, the high-pressure normal drainage No. 3 cannot automatically flow to the deaerator step by step, the high-pressure normal drainage No. 3 is connected to the condenser, and saturated steam and saturated water which are flashed out by utilizing high-energy drainage are utilized as much as possible. In addition, when the high-energy hydrophobic amount is larger, the operation is stopped, the No. 5 low-pressure heater is used, more saturated steam and saturated water are used for heating condensed water, the maximization of energy utilization is realized, and the operation economy of the unit under the deep peak regulation and 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 20% of the rated load (70MW), 90t of high-energy drain water is separated from a boiler in a wet state, after the unit is transformed by the method, a 0.8MPa flash tank is introduced to generate 23t of saturated steam and 67t of saturated water, and the saturated steam and the saturated water are respectively introduced into a steam side inlet and a water side inlet of a deaerator after the saturated steam and the saturated water are decompressed to 0.5 MPa. The operating pressure of the deaerator is 0.5MPa, the No. 3 high-pressure normal drainage is connected into the condenser through the critical drainage pipeline, the No. 5 low-pressure normal drainage is stopped, and all saturated steam and saturated water are recycled by the unit.
The thermal equilibrium diagram of the unit after recovery of high energy hydrophobic modification at 20% of rated load was simulated by Ebsilon software, as shown in fig. 2. Calculated, when 90t of high-energy hydrophobic water is completely discharged into a condenser, the heat consumption rate of a unit is about 10068kJ/(kWh), and the reduced coal consumption rate is about 377.2 g/(kWh); after transformation and recovery, 90t of high-energy drainage enters a flash tank, generated saturated steam and saturated water are all introduced into a deaerator, 3 # high-pressure normal drainage is connected into the condenser, 5 # low-pressure normal drainage is stopped, the heat consumption rate of a unit is about 9350kJ/(kWh), the reduced coal consumption rate is about 350.3g/(kWh), and compared with the heat consumption rate when the water is discharged into the condenser and is not recycled, the heat consumption rate is reduced by 718kJ/(kWh), the coal consumption rate is reduced by 20g/(kWh), and the reduction range is about 7.13%. Therefore, the heat consumption rate and the coal consumption rate of the unit after the recovery high-energy hydrophobic modification are greatly reduced under the rated load of 20 percent, and the operation economy is greatly improved.
Claims (9)
1. The utility model provides a thermal power generating unit high-quality working medium cyclic utilization system, a serial communication port, including water storage tank (2), flash tank (1) is connected in water storage tank (2), oxygen-eliminating device (3) are connected in flash tank (1), low pressure feed water heater (4) and high pressure feed water heater (5) are connected in oxygen-eliminating device (3) to oxygen-eliminating device (3), the saturated steam of flash tank (1) lets in the vapour side of oxygen-eliminating device (3), a condensate water for heating gets into oxygen-eliminating device (3), the water side that the saturated water of flash tank (1) lets in oxygen-eliminating device (3) is used for continuing to heat the condensate water that gets into oxygen-eliminating.
2. The high-quality working medium recycling system of the thermal power generating unit according to claim 1, characterized in that a water feed pump (10) is arranged between the deaerator (3) and the high-pressure heater (5).
3. The high-quality working medium recycling system of the thermal power generating unit according to claim 1, characterized in that a water level overflow regulating valve (9) is arranged between the water storage tank (2) and the flash tank (1).
4. The high-quality working medium recycling system of the thermal power generating unit according to claim 1, characterized in that a saturated steam pressure reducing valve (6) is arranged on a saturated steam pipeline between the flash tank (1) and the deaerator (3).
5. The thermal power generating unit high-quality working medium recycling system is characterized in that a saturated water pressure reducing valve (7) is arranged on a saturated water pipeline between the flash tank (1) and the deaerator (3).
6. The thermal power generating unit high-quality working medium recycling system is characterized in that condensed water flows through the low-pressure heater (4) and feed water flows through the high-pressure heater (5).
7. The thermal power generating unit high-quality working medium recycling system is characterized in that drainage of the high-pressure heater (5) is introduced into the condenser (8).
8. The working method of the thermal power generating unit high-quality working medium recycling system is characterized by comprising the following steps of:
step one, introducing high-energy hydrophobic water into a flash tank (1) by a water storage tank (2) to generate saturated steam and saturated water;
step two, introducing saturated steam of the flash tank (1) into the deaerator (3) to replace the original four-stage steam extraction, heating the condensed water entering the deaerator (3), and introducing the saturated water of the flash tank (1) into the water side of the deaerator (3) to continue heating the condensed water entering the deaerator (3);
and step three, boosting the pressure of the heated condensed water by a water supply pump, and then sending the boosted condensed water into a high-pressure heater (5).
9. The operating method of the high-energy heat-mass recovery system of the thermal power plant according to claim 8, characterized in that when the drainage pressure of the high-pressure heater (5) is lower than the operating pressure of the deaerator, the drainage of the high-pressure heater (5) is connected to the condenser (8).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010864942.XA CN111964028A (en) | 2020-08-25 | 2020-08-25 | Thermal power generating unit high-quality working medium recycling system and working method |
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| CN202010864942.XA CN111964028A (en) | 2020-08-25 | 2020-08-25 | Thermal power generating unit high-quality working medium recycling system and working method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| CN113756890A (en) * | 2021-09-06 | 2021-12-07 | 西安热工研究院有限公司 | Bypass system optimization method for solving problem of unsmooth drainage of deep peak shaving operation heater |
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| CN102650424A (en) * | 2011-06-02 | 2012-08-29 | 章礼道 | Direct-current furnace starting system matched with middle-pressure flash tank and used for comprehensively recycling working medium and heat |
| CN104713074A (en) * | 2015-03-25 | 2015-06-17 | 西安热工研究院有限公司 | System and method for recycling once-through boiler start-up drained water through pressure flash vessel |
| CN208312353U (en) * | 2018-05-08 | 2019-01-01 | 中国能源建设集团科技发展有限公司 | A kind of hydrophobic heat recovery system of power plant steam turbine |
| CN111322602A (en) * | 2020-03-13 | 2020-06-23 | 山西大学 | Circulating fluidized bed boiler system and deep peak shaving method using same |
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2020
- 2020-08-25 CN CN202010864942.XA patent/CN111964028A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102175021A (en) * | 2011-01-27 | 2011-09-07 | 章礼道 | Pump-free direct current furnace starting system capable of recycling working medium and heat comprehensively |
| CN102650424A (en) * | 2011-06-02 | 2012-08-29 | 章礼道 | Direct-current furnace starting system matched with middle-pressure flash tank and used for comprehensively recycling working medium and heat |
| CN104713074A (en) * | 2015-03-25 | 2015-06-17 | 西安热工研究院有限公司 | System and method for recycling once-through boiler start-up drained water through pressure flash vessel |
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| CN111322602A (en) * | 2020-03-13 | 2020-06-23 | 山西大学 | Circulating fluidized bed boiler system and deep peak shaving method using same |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| CN113756890A (en) * | 2021-09-06 | 2021-12-07 | 西安热工研究院有限公司 | Bypass system optimization method for solving problem of unsmooth drainage of deep peak shaving operation heater |
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Application publication date: 20201120 |