CN114659094A - Thermoelectric decoupling system and method based on boiler superheated steam shunting - Google Patents

Thermoelectric decoupling system and method based on boiler superheated steam shunting Download PDF

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Publication number
CN114659094A
CN114659094A CN202210433644.4A CN202210433644A CN114659094A CN 114659094 A CN114659094 A CN 114659094A CN 202210433644 A CN202210433644 A CN 202210433644A CN 114659094 A CN114659094 A CN 114659094A
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CN
China
Prior art keywords
superheater
steam
splitting
outlet
shunting
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Pending
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CN202210433644.4A
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Chinese (zh)
Inventor
王刚
邹洋
赵朋山
王心怡
韩志江
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Shanghai Boiler Works Co Ltd
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Shanghai Boiler Works Co Ltd
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Priority to CN202210433644.4A priority Critical patent/CN114659094A/en
Publication of CN114659094A publication Critical patent/CN114659094A/en
Pending legal-status Critical Current

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22GSUPERHEATING OF STEAM
    • F22G5/00Controlling superheat temperature
    • F22G5/12Controlling superheat temperature by attemperating the superheated steam, e.g. by injected water sprays
    • F22G5/123Water injection apparatus
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22GSUPERHEATING OF STEAM
    • F22G7/00Steam superheaters characterised by location, arrangement, or disposition

Abstract

The invention provides a thermoelectric decoupling system based on boiler superheated steam shunting, which relates to the field of boilers and comprises a water-cooled wall, a primary superheater, a secondary superheater and a tertiary superheater which are sequentially connected, wherein a primary water spray temperature reduction device is arranged between the outlet of the primary superheater and the inlet of the secondary superheater, a secondary water spray temperature reduction device is arranged between the outlet of the secondary superheater and the inlet of the tertiary superheater, and more than one shunting point for shunting steam is arranged on a connecting pipeline between the water-cooled wall and the tertiary superheater. The amount of steam entering a steam turbine is reduced through steam shunting, the generated energy is reduced, and the thermoelectric decoupling function of a thermal power generating unit is realized; the minimum output load can be reduced to below 15% on the premise of ensuring large-scale heat supply load, a proper shunting point can be selected according to the actual steam extraction and heat utilization requirements of users, and the grade of equipment materials such as shunting pipelines, valves and the like is reduced, so that the investment cost of the system is greatly reduced.

Description

Thermoelectric decoupling system and method based on boiler superheated steam shunting
Technical Field
The invention belongs to the field of boilers, and particularly relates to a thermoelectric decoupling system and method based on boiler superheated steam shunting.
Background
The coal-fired power generation proportion is in a descending trend under the background of 'double carbon', the flexible peak regulation of the thermal power unit is normalized gradually, and meanwhile, the thermal power unit also needs to undertake the tasks of steam supply and heating in the heating period. Therefore, thermal power plants at present need to perform thermoelectric decoupling to meet the requirement of deep peak regulation. The thermoelectric decoupling can enlarge the output adjustment range of the unit and reduce the proportion of the generated energy and the calorific value in the cogeneration process.
The technology for realizing thermoelectric decoupling in the prior art mainly comprises a low-pressure cylinder cutting technology, a bypass steam heat supply technology, an electric boiler technology and a battery energy storage technology. The low-pressure cylinder cutting technology leads all the exhaust steam of the medium-pressure cylinder out through a steam extraction pipeline, only a small amount of cooling steam is reserved to enter the low-pressure cylinder, so that the low-pressure cylinder does not work, although the scheme can greatly reduce the power supply load of the unit, the total load of the unit is about 40 percent due to the high operation load of the medium-pressure cylinder, and deeper thermoelectric decoupling cannot be performed; the electric boiler technology utilizes the electric energy of the unit to generate heat energy, and has the problems of low efficiency and the like; the bypass steam heat supply technology utilizes a steam bypass system during the starting period of the unit, superheated steam is subjected to temperature reduction and pressure reduction and then is supplied with heat, the quality of the steam is reduced, the bypass system is designed under low load, the flow of the extracted steam is small, and the thermoelectric decoupling degree is insufficient; the battery energy storage technology has higher cost and potential safety hazard. Therefore, the optimization of the thermoelectric decoupling technology to realize the deeper peak regulation capability of the unit has important significance.
Disclosure of Invention
The invention aims to solve the technical problem of providing a thermoelectric decoupling system and a thermoelectric decoupling method based on boiler superheated steam shunting, and realizing the deep-adjusting capacity of a unit below 15% on the premise of ensuring the energy utilization efficiency and the steam quality of the unit.
In order to solve the technical problem, the invention provides a thermoelectric decoupling system based on boiler superheated steam shunting, which comprises a water wall, a primary superheater, a secondary superheater and a tertiary superheater which are sequentially connected, wherein a primary water spray attemperator is arranged between an outlet of the primary superheater and an inlet of the secondary superheater, a secondary water spray attemperator is arranged between an outlet of the secondary superheater and an inlet of the tertiary superheater, and more than one shunting point for shunting steam is arranged on a connecting pipeline between the water wall and the tertiary superheater.
Furthermore, a branch flow point is arranged on a connecting pipeline between the water wall and the tertiary superheater, and the branch flow point is positioned at an outlet of the water wall, an outlet of the primary superheater or an outlet of the secondary superheater.
Furthermore, two flow dividing points are arranged on a connecting pipeline between the water wall and the tertiary superheater, and the two flow dividing points are respectively positioned at an outlet of the water wall and an outlet of the primary superheater, an outlet of the water wall and an outlet of the secondary superheater or an outlet of the primary superheater and an outlet of the secondary superheater.
Furthermore, three shunting points are arranged on a connecting pipeline between the water wall and the tertiary superheater, and the three shunting points are respectively positioned at an outlet of the water wall, an outlet of the primary superheater and an outlet of the secondary superheater.
Furthermore, a flow regulating valve is arranged on the flow dividing pipeline connected with the flow dividing point.
Furthermore, a pressure relief valve is arranged on the flow dividing pipeline connected with the flow dividing point, and the pressure of the divided steam is adjusted through the pressure relief valve according to the requirements of users.
The method for thermoelectric decoupling by using the thermoelectric decoupling system based on boiler superheated steam shunting comprises the steps of carrying out steam shunting from shunting points when the number of the shunting points is one during thermoelectric decoupling, and selecting one shunting point from a plurality of shunting points to carry out steam shunting when the number of the shunting points is more than two.
Further, after the steam is split, the water spray attemperating device in front of the selected splitting point operates normally, and the water spray attemperating device behind the selected splitting point operates by increasing the water spray amount.
The heat that steam absorbed in the over heater is certain, if the import steam volume of over heater becomes low, then the temperature of export steam will be higher than former design value, because the material that the boiler was made all is according to the temperature everywhere, the suitable material of pressure selection, consequently in case take place the overtemperature, the material will take place to damage to the unable normal operating of boiler, consequently extract behind the steam, need carry out the water spray desuperheating before getting into the over heater, make the export temperature of over heater always within the safe value. In addition, because the steam temperature of the residual steam heated by the superheater is different due to different positions of extracted steam, in order to ensure that the temperature is always within a safe range, the water spraying amount of the water spraying temperature reducing device behind the flow dividing point needs to be controlled respectively, and the specific value of the water spraying amount is determined according to the characteristics that the extracted amount of the steam and the absorbed heat are constant.
During the non-peak-shaving period, the water spraying temperature reduction device is in a normal operation state, quantitative water is sprayed, the safe operation of the boiler is ensured, and related parameters are determined according to the design process of the boiler; during the peak regulation period, namely during the thermoelectric decoupling period, the water spraying amount of the water spraying temperature reduction device needs to be increased according to the designed steam extraction amount, the safe operation of the subsequent heating surfaces of all levels of the water spraying temperature reduction device is ensured, and potential safety hazards such as overtemperature and the like do not occur.
Further, during thermoelectric decoupling, the split steam flow at the split point does not exceed 50% of the pre-split steam flow.
Has the advantages that:
the invention provides a thermoelectric decoupling system based on boiler superheated steam shunting, which comprises a water wall, a primary superheater, a secondary superheater and a tertiary superheater which are sequentially connected, wherein a primary water spraying temperature reduction device is arranged between an outlet of the primary superheater and an inlet of the secondary superheater, a secondary water spraying temperature reduction device is arranged between an outlet of the secondary superheater and an inlet of the tertiary superheater, and more than one shunting point for shunting steam is arranged on a connecting pipeline between the water wall and the tertiary superheater. The amount of steam entering a steam turbine is reduced through steam shunting, the generated energy is reduced, and the thermoelectric decoupling function of the thermal power generating unit is realized; the heat energy of the steam is directly utilized, so that the conversion between energy forms, such as electric energy-heat energy conversion, is avoided, and the energy utilization efficiency of the unit is ensured; the technical scheme has no influence on the heat supply load of a boiler part, the output load can be reduced on the premise, the specific minimum output load is determined according to the minimum output load of the steam turbine, and the minimum output load of the steam turbine is about 15% under the general condition, so that the minimum output load of the unit can be reduced to below 15% on the premise of ensuring the large-scale heat supply load, a proper shunting point can be selected according to the actual steam extraction heat demand of a user, the grades of equipment materials such as shunting pipelines, valves and the like are reduced, and the investment cost of the system is greatly reduced.
The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.
Drawings
FIG. 1 is a thermoelectric decoupling system based on boiler superheated steam splitting;
reference numerals:
1. a water cooled wall; 2. a primary superheater; 3. a secondary superheater; 4. a tertiary superheater; 5. a first stage water spray desuperheating device; 6. a secondary water spray temperature reduction device; 7. a flow regulating valve; 8. a first tapping point; 9. a second tapping point; 10. a third tapping point.
Detailed Description
The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.
Example 1:
as shown in fig. 1, in a preferred embodiment, each design parameter of a certain 660MW ultra supercritical generator set is taken as a boundary condition, and a thermoelectric decoupling system based on boiler superheated steam splitting is provided, including a water wall 1, a primary superheater 2, a secondary superheater 3, a tertiary superheater 4, a primary water spray attemperating device 5, a secondary water spray attemperating device 6, and three splitting points, where the three splitting points are a first splitting point 8, a second splitting point 9, and a third splitting point 10, the first splitting point 8, the second splitting point 9, and the third splitting point 10 are respectively located at an outlet of the water wall 1, an outlet of the primary superheater 2, and an outlet of the secondary superheater 3, and flow regulating valves 7 are respectively disposed on splitting pipelines connected to the first splitting point 8, the second splitting point 9, and the third splitting point 10.
The first-stage water spraying temperature reducing device 5 is respectively connected with the outlet of the first-stage superheater 2 and the inlet of the second-stage superheater 3, and the second-stage water spraying temperature reducing device 6 is respectively connected with the outlet of the second-stage superheater 3 and the inlet of the third-stage superheater 4.
Boiler feed water becomes steam after passing through the water wall 1, and then becomes superheated steam at the outlet of the boiler after passing through the primary superheater 2, the secondary superheater 3 and the tertiary superheater 4.
The method for performing thermoelectric decoupling by using the thermoelectric decoupling system based on boiler superheated steam shunting comprises the following steps:
the boiler operates at the lowest load of 30 percent, the steam turbine operates at the lowest feasible load of about 15 percent, the mass flow, the temperature and the pressure of steam at the outlet of the water-cooled wall 1 are 565t/h, 392 ℃ and 10.29MPa respectively, 280t/h of steam is extracted from a first diversion point 8, and superheated steam of 3MPa, 320 ℃ and 280t/h can be provided for a user after pressure is released through a pressure release valve; the water spraying amount of the first-stage water spraying temperature reducing device 5 needs to be increased to 55t/h, and the water spraying amount of the second-stage water spraying temperature reducing device 6 needs to be increased to 20t/h, so that the safe operation of the system is ensured.
Example 2:
the thermoelectric decoupling system based on boiler superheated steam splitting provided in the embodiment is the same as the first embodiment, and the difference is that:
during the thermoelectric decoupling period, the boiler operates at the lowest load of 30 percent, the steam turbine operates at the lowest feasible load of about 15 percent, the mass flow, the temperature and the pressure of steam at the outlet of the primary superheater 2 are 565t/h, 420 ℃ and 10.29MPa respectively, 280t/h of steam is extracted from a second diversion point 9, and superheated steam of 3MPa, 360 ℃ and 280t/h can be provided for a user after heat exchange through the heat exchanger; the water spraying amount of the first-stage water spraying temperature reducing device 5 needs to be increased to 40t/h, and the water spraying amount of the second-stage water spraying temperature reducing device 6 needs to be increased to 20t/h, so that the safe operation of the system is ensured.
Example 3:
the thermoelectric decoupling system based on boiler superheated steam splitting provided in the embodiment is the same as the first embodiment, and the difference is that:
during the thermoelectric decoupling, the boiler operates at the lowest load of 30 percent, the steam turbine operates at the lowest feasible load of about 15 percent, the mass flow, the temperature and the pressure of steam at the outlet of the secondary superheater 3 are 565t/h, 566 ℃ and 10.29MPa respectively, 280t/h of steam is extracted from the third diversion point 10, and the superheated steam at 3MPa, 520 ℃ and 280t/h can be provided for a user after heat exchange through the heat exchanger; the first-stage water spraying temperature reduction device 5 operates normally, and the second-stage water spraying temperature reduction device 6 needs to increase the water spraying amount to 20t/h so as to ensure the safe operation of the system.
Therefore, the thermoelectric decoupling function of the thermal power generating unit can be realized, the minimum output load of the thermal power generating unit can be reduced to below 15% on the premise of ensuring large-scale heat supply load, a proper shunting point can be selected according to the actual steam extraction and heat utilization requirements of users, the grade of equipment materials such as shunting pipelines and valves is reduced, and the system investment cost is greatly reduced.
Finally, it should be noted that: the present invention is not limited to the above embodiments, and all equivalent structures or equivalent flow transformations which are made by using the contents of the specification and the drawings of the present invention, or which are directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (9)

1. The utility model provides a thermoelectric decoupling system based on boiler superheated steam shunts which characterized in that, including water-cooling wall (1), one-level over heater (2), second grade over heater (3) and tertiary over heater (4) that connect gradually, the export of one-level over heater (2) with set up one-level water spray attemperator (5) between the entry of second grade over heater (3), the export of second grade over heater (3) with set up second grade water spray attemperator (6) between the entry of tertiary over heater (4), set up more than one on the connecting pipeline between water-cooling wall (1) and tertiary over heater (4) and be used for shunting the reposition of redundant personnel steam.
2. The decoupling system of claim 1, wherein a splitting point is provided on a connecting pipeline between the water wall (1) and the tertiary superheater (4), and the splitting point is located at an outlet of the water wall (1), an outlet of the primary superheater (2) or an outlet of the secondary superheater (3).
3. The boiler superheated steam flow splitting-based thermoelectric decoupling system as claimed in claim 1, wherein two flow splitting points are arranged on a connecting pipeline between the water wall (1) and the tertiary superheater (4), and are respectively positioned at an outlet of the water wall (1) and an outlet of the primary superheater (2), an outlet of the water wall (1) and an outlet of the secondary superheater (3), or an outlet of the primary superheater (2) and an outlet of the secondary superheater (3).
4. The boiler superheated steam flow splitting-based thermoelectric decoupling system as claimed in claim 1, wherein three flow splitting points are arranged on a connecting pipeline between the water wall (1) and the tertiary superheater (4), and the three flow splitting points are respectively positioned at an outlet of the water wall (1), an outlet of the primary superheater (2) and an outlet of the secondary superheater (3).
5. The system for decoupling the heat and the electricity based on the diversion of the superheated steam of the boiler as claimed in claim 1, wherein a flow regulating valve (7) is arranged on a branch pipeline connected with a diversion point.
6. A system for decoupling thermal and electrical coupling based on splitting of superheated steam in a boiler as claimed in claim 1 wherein a pressure relief valve is provided on the splitting line connected to the splitting point for pressure relief of the split steam.
7. The method for thermoelectric decoupling by using the thermoelectric decoupling system based on boiler superheated steam splitting as claimed in claim 1, wherein during the thermoelectric decoupling, when the number of splitting points is one, the steam splitting is performed from the splitting point, and when the number of splitting points is more than two, one splitting point is selected from a plurality of splitting points to perform the steam splitting.
8. A method of thermoelectric decoupling as in claim 7 wherein after steam splitting, the spray attemperation device before the selected split point operates normally and the spray attemperation device after the selected split point operates with increased spray.
9. The method of thermoelectric decoupling of claim 7 wherein during thermoelectric decoupling the split steam flow at the split point is no more than 50% of the pre-split steam flow.
CN202210433644.4A 2022-04-22 2022-04-22 Thermoelectric decoupling system and method based on boiler superheated steam shunting Pending CN114659094A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN206144613U (en) * 2016-09-05 2017-05-03 华能国际电力股份有限公司 Thermoelectric decoupling zero heating system of steam is taken out from power plant boiler
CN207815281U (en) * 2018-02-01 2018-09-04 叶妮娜 The asynchronous load depth peak regulation system of thermal power plant unit steam turbine boiler
WO2018233024A1 (en) * 2017-06-22 2018-12-27 赫普热力发展有限公司 Thermoelectric decoupling peak load regulating system
CN110145376A (en) * 2018-10-07 2019-08-20 联合瑞升(北京)科技有限公司 A kind of boiler and steam turbine decoupled system based on increasing steam turbine
CN217464397U (en) * 2022-04-22 2022-09-20 上海锅炉厂有限公司 Thermoelectric decoupling system based on boiler superheated steam reposition of redundant personnel

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN206144613U (en) * 2016-09-05 2017-05-03 华能国际电力股份有限公司 Thermoelectric decoupling zero heating system of steam is taken out from power plant boiler
WO2018233024A1 (en) * 2017-06-22 2018-12-27 赫普热力发展有限公司 Thermoelectric decoupling peak load regulating system
CN207815281U (en) * 2018-02-01 2018-09-04 叶妮娜 The asynchronous load depth peak regulation system of thermal power plant unit steam turbine boiler
CN110145376A (en) * 2018-10-07 2019-08-20 联合瑞升(北京)科技有限公司 A kind of boiler and steam turbine decoupled system based on increasing steam turbine
CN217464397U (en) * 2022-04-22 2022-09-20 上海锅炉厂有限公司 Thermoelectric decoupling system based on boiler superheated steam reposition of redundant personnel

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