CN115059907A - Method for rapidly cooling ultra-supercritical thermal power generating unit without stopping furnace - Google Patents
Method for rapidly cooling ultra-supercritical thermal power generating unit without stopping furnace Download PDFInfo
- Publication number
- CN115059907A CN115059907A CN202210514150.9A CN202210514150A CN115059907A CN 115059907 A CN115059907 A CN 115059907A CN 202210514150 A CN202210514150 A CN 202210514150A CN 115059907 A CN115059907 A CN 115059907A
- Authority
- CN
- China
- Prior art keywords
- load
- boiler
- pressure
- furnace
- reduced
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 71
- 238000001816 cooling Methods 0.000 title claims abstract description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000003245 coal Substances 0.000 claims abstract description 34
- 239000000446 fuel Substances 0.000 claims abstract description 30
- 230000009467 reduction Effects 0.000 claims abstract description 13
- 238000002485 combustion reaction Methods 0.000 claims abstract description 12
- 239000000843 powder Substances 0.000 claims abstract description 9
- 238000007599 discharging Methods 0.000 claims abstract description 8
- 230000003828 downregulation Effects 0.000 claims abstract description 4
- 238000010926 purge Methods 0.000 claims description 14
- 238000009423 ventilation Methods 0.000 claims description 13
- 238000010298 pulverizing process Methods 0.000 claims description 12
- 239000000779 smoke Substances 0.000 claims description 3
- 239000013589 supplement Substances 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 20
- 238000010438 heat treatment Methods 0.000 description 11
- 230000003247 decreasing effect Effects 0.000 description 5
- 230000000630 rising effect Effects 0.000 description 5
- 230000035882 stress Effects 0.000 description 5
- 238000007664 blowing Methods 0.000 description 4
- 230000018109 developmental process Effects 0.000 description 3
- 238000010248 power generation Methods 0.000 description 3
- 230000008439 repair process Effects 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000006837 decompression Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000008400 supply water Substances 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B35/00—Control systems for steam boilers
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Abstract
The invention discloses a method for rapidly cooling an ultra-supercritical thermal power generating unit without stopping a furnace, which comprises the following steps: according to the load down-regulation requirement of the unit, the combustion strength in the boiler is reduced; acquiring the load of the unit, sequentially starting an electric feed pump, a boiler circulating pump and a manual switch-on high-low side when the load of the unit is reduced to a preset value, and switching on a steam turbine after the load is continuously reduced in place; acquiring furnace pressure in real time, and maintaining the speed of pressure reduction and temperature reduction and reducing the furnace pressure to a preset value by stably reducing the fuel quantity and adjusting the high-low side opening degree; acquiring the condition of the running fuel quantity, if the powder preparation system is completely empty, putting an oil gun to provide fuel, and after the coal mill is completely emptied, withdrawing the oil gun, shutting down the high-low side and carrying out furnace closing; and after the pressure relief condition is met, discharging water under pressure in the boiler. The invention realizes the purpose of rapid cooling by stopping the machine without stopping the furnace and operating with deep sliding parameters, and solves the problems that the conventional furnace stopping cooling has long depressurization time, can not be overhauled and eliminated as soon as possible and meets the requirements of a power grid.
Description
Technical Field
The invention relates to the technical field of cooling of ultra-supercritical thermal power generating units, in particular to a non-shutdown rapid cooling method for an ultra-supercritical thermal power generating unit.
Background
With the continuous improvement of equipment level and power generation efficiency of new energy power equipment represented by wind power and photovoltaic power generation in China, new energy is rapidly developed. However, the new energy is obviously affected by weather on the aspect of power supply, has the characteristics of large fluctuation and uncertainty, a process is needed for development and construction of the new energy and innovation and development of a large-capacity energy storage technology matched with the new energy, and due to large economic quantity, high development speed and high energy utilization requirement in China, the thermal power generation still can bear the functions of basic energy supply, auxiliary peak regulation, bottom supporting and absorption and the like of the new energy in the whole society within a long time in the future. In addition, the problems of annual peak-valley difference and day-night peak-valley difference of power grid load become more and more serious, so that the requirements on the reliability and the flexibility of a coal-fired unit are higher and higher.
However, with the increase of the in-service time of the unit, the problem of equipment aging gradually appears, and in addition, frequent start-stop and deep peak shaving of the unit, corrosion, scaling, abrasion of the heating surface of the boiler, interaction of high temperature, high pressure and the like cause increasingly serious problems of stress fatigue of the heating surface and scale shedding, the problem of leakage of a water wall pipe is easy to occur, and once leakage of the water wall occurs, shutdown treatment is required.
At present, a boiler is designed to carry a basic load and participate in peak shaving, the boiler operates in a pure direct current mode within the load range of 30% to 100%, the boiler operates in a recirculation mode of a circulating pump below 30% of load, and a conventional boiler blowing-out cooling mode is that in the process of reducing the load of a unit, a coal bunker is gradually burnt out, the circulating pump of the boiler is started, and the boiler operates in a wet state. The load is reduced to be below 250MW, the high side and the low side are opened manually, and the side load of the steam turbine is reduced. When the electric load is not higher than 50MW, the steam turbine is opened. When the coal feeder runs empty, all fuels are cut off, the high and low sides are closed, and the pressure of a steam-water separator of the boiler is about 10 MPa. And (3) stopping the boiler after the boiler is purged, naturally releasing the pressure to 1.0MPa, discharging water under pressure, and cooling by natural ventilation and forced ventilation, wherein the water-cooled wall of the boiler has overhaul conditions.
In the traditional blowing-out cooling mode, because the cooling and pressure reduction time of a boiler is long, the boiler cannot be overhauled and eliminated as soon as possible so as to recover the hot standby and grid-connected operation of a unit and cannot meet the requirement of a power grid. Therefore, with the increasingly severe contradiction between the temporary repair shortage of the unit and the power utilization shortage, how to rapidly stop and cool the unit can be achieved, conditions are created for the first-aid repair of the unit, the temporary repair time of the unit is shortened, the load requirement of the power grid belt is responded in time, and the method becomes a new challenge for thermal power enterprises.
Disclosure of Invention
The invention aims to provide a method for rapidly cooling an ultra-supercritical thermal power generating unit without stopping a furnace, which solves the problems that the conventional furnace stopping cooling decompression time is long, the defect cannot be eliminated as soon as possible through overhauling, and the power grid requirement is met, and comprises the following steps:
according to the load down-regulation requirement of the unit, the combustion intensity in the boiler is reduced;
acquiring the load of the unit in real time, sequentially starting an electric feed pump, a boiler circulating pump and a manual switch-on high-low side when the load of the unit is reduced to a preset value, and switching off a steam turbine after the load is continuously reduced in place;
acquiring furnace pressure in real time, and maintaining the speed of pressure reduction and temperature reduction and reducing the furnace pressure to a preset value by stably reducing the fuel quantity and adjusting the high-low side opening degree;
acquiring the condition of the running fuel quantity in real time, if the pulverizing system is completely empty, putting an oil gun to provide fuel, and after the coal mill is completely emptied, withdrawing the oil gun, shutting down the high-low side and carrying out furnace closing;
and after the pressure relief condition is met, discharging water under pressure in the boiler.
In some embodiments of the present application, a particular method of operation is provided, the method steps comprising:
step S1, completing the switching operation of the public and auxiliary systems within a certain time;
step S2, when the load of the unit is reduced to the first load, the steam source of a steam-driven water-feeding pump is switched to an auxiliary steam connecting belt;
step S3, when the load of the unit is reduced to a second load, starting a boiler circulating pump, and operating in a wet state;
step S4, when the load of the unit is reduced to a third load, the height of the unit is manually increased, the fuel quantity is reduced, and the load of the unit is continuously reduced until the steam turbine is executed to open the brake;
step S5, maintaining the furnace side combustion, and gradually reducing the main steam pressure by reducing the high and low side pressure setting;
step S6, when the pressure of the main steam is reduced to be below 4MPa, the last powder making system is shut down, an oil gun is put into the last powder making system, after the coal mill is blown empty, the oil gun is withdrawn, the boiler MFT is started, and the high-low side is closed;
step S7, after the boiler is continuously purged, executing a furnace closing procedure of a wind and smoke system;
step S8, discharging water under pressure by the boiler when the pressure of the steam-water separator is reduced to 1 MPa;
and step S9, after the water discharge of the boiler is finished, the boiler carries out natural ventilation or starts a draught fan to carry out forced ventilation.
In some embodiments of the present application, in order to optimize the unit shutdown operation, the method is modified, in step S1, the time is 30 minutes, and the operations are switched from auxiliary steam supply, heat supply and system water supplement to external system supply.
In some embodiments of the present application, in order to ensure the stability of the furnace combustion during the furnace shutdown process, especially in the late furnace shutdown period, the method is improved, in step S2, when the unit load is reduced to 400MW, plasma is put into the boiler for stable combustion.
In some embodiments of the present application, to determine when to switch the water supply pump steam source to the auxiliary steam splicing zone, the method is modified in that in step S2, the first load is 380-.
In some embodiments of the present application, in order to determine the timing for starting the boiler circulation pump when the unit is in wet operation, the method is modified, and in step S3, the second load is 300-.
In some embodiments of the present application, in order to ensure that the turbine can meet the requirement of reducing the operation speed under the condition of preset parameters during the furnace shutdown process, the method is improved in step S4, when the load of the unit is reduced to 200MW, the reheater pressure is manually gradually opened to 1.5-2MPa, when the load of the generator is not higher than 50MW, the turbine is opened, the generator is connected to jump, and the amount of coal after opening is controlled to be not more than 90 t/h.
In some embodiments of the present application, in order to keep the depressurization process stable and ensure that the reheated steam pressure meets the requirement of subsequent blower purging, the method is improved, in step S5, two pulverizing systems are kept running, the coal quantity is gradually reduced to reduce the heat load of the boiler, the high-low side is kept in an automatic manner, the main steam pressure is gradually and stably reduced by reducing the set value of the high side pressure, and the set value of the low side is kept at 2.0 MPa.
In some embodiments of the present application, in order to determine the final shutdown time, the method is modified, in step S6, the main steam pressure is gradually decreased to below 4MPa, the total fuel amount is decreased to 25t/h, the shutdown procedure may be performed, all pulverizing systems are deactivated, the coal mill is emptied, the oil lance is withdrawn, the boiler MFT is turned off, and the high-low side is turned off.
In some embodiments of the application, in order to ensure that the purging time is sufficient, the method is improved in step S7, the induced draft fan is driven by the residual steam to purge the hearth, the purging time is 10 minutes, and the induced draft fan is stopped after the purging is finished.
In some embodiments of the present application, the method is modified to ensure the furnace-stuffiness to bring the boiler to a specified state, and in said step S8, the furnace-stuffiness time is 4-5 hours.
In some embodiments of the present application, in order to ensure sufficient ventilation of the boiler, the method is modified in that the natural ventilation time is 0 to 12 hours in the step S9.
The application discloses method for rapidly cooling ultra-supercritical thermal power generating unit without blowing out boiler, and by optimizing unit shutdown operation, load reducing time of the unit is shortened, and deep slip parameter blowing out operation enables boiler to be rapidly decompressed, and cooling time is shortened.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a flow chart illustrating the steps of a method for rapid cooling without shutdown in an embodiment of the present application;
FIG. 2 is a schematic illustration of a pressure control curve in the present application;
FIG. 3 is a schematic illustration of a main reheat steam temperature control curve in the present application;
FIG. 4 is a comparison graph of the blowing out time nodes in an embodiment of the present application;
FIG. 5 is a comparison of the time consumed during various phases of unit outage in an embodiment of the present application.
Detailed Description
The technical solution of the present invention is further illustrated by the accompanying drawings and examples.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
Along with the increase of the service time of the ultra-supercritical thermal power generating unit, the aging problem of equipment is gradually shown, and in addition, the problems of stress fatigue of a heating surface and oxide skin shedding are increasingly serious due to frequent start-stop and deep peak regulation of the unit, corrosion, scaling and abrasion of the heating surface of a boiler, interaction of high temperature, high pressure and the like, the problem of leakage of a water wall pipe is easy to occur, and once leakage of a water wall occurs, shutdown treatment is required. In the traditional blowing-out cooling mode, because the cooling and pressure reduction time of a boiler is long, the boiler cannot be overhauled and eliminated as soon as possible so as to recover the hot standby and grid-connected operation of a unit and cannot meet the requirement of a power grid.
The invention aims to provide a method for rapidly cooling an ultra-supercritical thermal power generating unit without stopping a furnace, which solves the problems that the conventional furnace stopping cooling decompression time is long, the defect cannot be eliminated as soon as possible through overhauling, and the power grid requirement is met, and comprises the following steps: the method comprises the following steps:
according to the load down-regulation requirement of the unit, the combustion strength in the boiler is reduced;
acquiring unit load in real time, and starting an electric pump for standby rotation and starting a high-low side in sequence when the unit load is reduced to a preset value;
acquiring the running condition of a coal pulverizing system in real time, if the coal burning quantity is reduced to a preset value, putting an oil gun into a boiler to provide fuel, and if the coal mill is blown empty, withdrawing the oil gun;
and acquiring the main steam pressure in real time, and closing the high-low side if the main steam pressure is reduced to a preset value and is stable.
In some embodiments of the present application, a specific method of operation is provided, the method steps as described in fig. 1 comprising:
step S1, completing the switching operation of the public and auxiliary systems within a certain time;
step S2, when the load of the unit is reduced to the first load, the steam source of a steam-driven water-feeding pump is switched to an auxiliary steam connecting belt;
step S3, when the load of the unit is reduced to a second load, starting a boiler circulating pump, and operating in a wet state;
step S4, when the load of the unit is reduced to a third load, the high-low side is opened manually, the fuel quantity is reduced, and the load of the unit is reduced continuously until the steam turbine is opened;
step S5, maintaining the furnace side combustion, and gradually reducing the main steam pressure by reducing the high and low side pressure setting;
step S6, when the pressure of the main steam is reduced to be below 4MPa, the last powder making system is shut down, an oil gun is put into the last powder making system, after the coal mill is blown empty, the oil gun is withdrawn, the boiler MFT is started, and the high-low side is closed;
step S7, after the boiler is continuously purged, executing a furnace closing procedure of a wind and smoke system;
step S8, discharging water under pressure by the boiler when the pressure of the steam-water separator is reduced to 1 MPa;
and step S9, after the water discharge of the boiler is finished, the boiler carries out natural ventilation or starts a draught fan to carry out forced ventilation.
In some embodiments of the present application, in order to optimize the unit shutdown operation, the method is modified, in step S1, the time is 30 minutes, and the operations are switched from auxiliary steam supply, heat supply and system water supplement to external system supply.
In some embodiments of the present application, in order to ensure the stability of the furnace combustion during the furnace shutdown process, especially in the late furnace shutdown period, the method is improved, in step S2, when the unit load is reduced to 400MW, plasma is put into the boiler for stable combustion.
In some embodiments of the present application, to determine when to switch the water supply pump steam source to the auxiliary steam splicing zone, the method is modified in that in step S2, the first load is 380-.
In some embodiments of the present application, in order to determine the timing for starting the boiler circulation pump when the unit is in wet operation, the method is modified, and in step S3, the second load is 300-.
In some embodiments of the present application, in order to ensure that the turbine can meet the requirement of reducing the operation speed under the condition of preset parameters during the furnace shutdown process, the method is improved in step S4, when the load of the unit is reduced to 200MW, the reheater pressure is manually gradually opened to 1.5-2MPa, when the load of the generator is not higher than 50MW, the turbine is opened, the generator is connected to jump, and the amount of coal after opening is controlled to be not more than 90 t/h.
In some embodiments of the present application, in order to keep the depressurization process stable and ensure that the reheat steam pressure meets the requirement of subsequent blower purging, the method is improved, in step S5, two pulverizing systems are kept running, the coal quantity is gradually reduced to reduce the heat load of the boiler, the high-low side is kept in an automatic mode, the main steam pressure is gradually and stably reduced by reducing the set value of the high side pressure, and the set value of the low side is kept unchanged at 2.0 MPa.
In some embodiments of the present application, in order to determine the final shutdown time, the method is modified, in step S6, the main steam pressure is gradually decreased to below 4MPa, the total fuel amount is decreased to 25t/h, the shutdown procedure may be performed, all pulverizing systems are deactivated, the coal mill is emptied, the oil lance is withdrawn, the boiler MFT is turned off, and the high-low side is turned off.
In some embodiments of the application, in order to ensure that the purging time is sufficient, the method is improved in step S7, the induced draft fan is driven by the residual steam to purge the hearth, the purging time is 10 minutes, and the induced draft fan is stopped after the purging is finished.
In some embodiments of the present application, the method is modified to ensure the furnace-stuffiness to bring the boiler to a specified state, and in said step S8, the furnace-stuffiness time is 4-5 hours.
In some embodiments of the present application, in order to ensure sufficient ventilation of the boiler, the method is modified, and in the step S9, the time of natural ventilation is 0-12 hours.
In the cold starting process of the once-through boiler, starting pressure and starting flow are established through an electric water feeding pump and a starting circulating pump so as to ensure cooling of all heating surfaces and stability of hydrodynamics in a water wall, and the pressure rising rate of main steam is controlled to be not more than 0.028MPa/min and the temperature rising rate is controlled to be not more than 1.25 ℃/min by adjusting the fuel quantity, the flow of the electric pump and the high side opening degree until the main steam pressure rises to 8.5MPa and the temperature rises to 380 ℃, so that the running of a steam turbine is completed. In the process, on the premise that the steam-water quality of the heating surface of the boiler meets the requirement, as long as enough working medium flows through the heating surface to cool the heating surface, the temperature of the metal wall is not more than the allowable temperature, and the temperature and the pressure rising rate of the main steam are controlled within the allowable range, the stress of the heating surface of the boiler and the scale falling amount can be effectively reduced, and the safety of the heating surface of the boiler is ensured.
Although the shutdown process only requires the Main steam pressure and temperature before the generator is disconnected in the boiler specification, the temperature drop and the pressure drop rate are limited, and the automatic protection measures for equipment during the operation of the boiler are generally taken by MFT (MFT, which is called Main Fuel Trip in the whole name and is the core content of boiler safety protection). For the boiler, whether the generator is disconnected or not, the stress requirement of the heating surface of the boiler can be met only by controlling the temperature drop and the pressure drop rate of the main steam, and the starting and stopping processes of the boiler are the pressure boosting and pressure reducing processes, so that the reverse process of the starting mode of the boiler can be adopted after the generator is disconnected, and the temperature drop and the pressure drop rate are controlled in a reasonable direction through the matching of reasonable fuel quantity, water supply quantity and bypass opening, so that the rapid pressure relief of the boiler is realized, the purpose of rapidly cooling the boiler is achieved, and the generator is feasible from the aspects of principle and equipment safety.
The main steam pressure and temperature are slowly reduced to achieve the purpose of quick cooling by adopting the principle of orderly reducing the fuel quantity and the water supply flow of the water supply pump and simulating the starting, temperature rising and pressure rising reverse operation of the boiler after the machine is shut down and the set is disconnected. As shown in fig. 2 and 3, the specific control process is as follows:
and (I) optimizing the shutdown operation of the unit, and shortening the time from load reduction to disconnection of the unit.
(1) And the related switching operation of the public and auxiliary systems (auxiliary steam, heat supply switching machine, auxiliary steam switching of a steam source of a steam pump) is completed within 30 minutes.
(2) In the shutdown process of the unit, the steam source of the steam-driven draught fan is not switched, and the unit is subjected to steam source connection again to complete the unit shutdown and the purging operation after the shutdown.
(3) The CCS mode (coordinated control system for realizing coordinated control load and pressure of a boiler and a steam turbine) reduces the load to 350MW, during the period, if pressure control needs to be carried out, the main steam pressure set value can be properly reduced through pressure setting offset, and the main steam pressure set value needs to be controlled not to be lower than 8.5MW before separation, so that the steam pump can normally discharge water. During the period, the air pump is withdrawn from the machine selection, and the electric pump is rotated for standby (the sum of the effective production capacity when the machine set synchronously operates under the current load requirement of the system).
(4) The load is reduced to 250MW by BID and the pressure set value is gradually reduced by the DEH side in a BI mode (DEH (digital electro-hydraulic control system of a steam turbine, and the control of the rotating speed, the load, the pressure and the like of a steam turbine generator unit) side-cutting local pressure. During the period, the wind, coal and water are automatically closed at the high and low sides. Note that the main and secondary steam temperatures need to be maintained as stable or slowly reduced as possible at this stage, and the load reduction stress margin is controlled to meet the requirement. The main steam pressure can be kept unchanged after the main steam pressure is reduced to 8.5MPa to 8.8MPa below 300MW, and the normal water outlet of the steam pump is ensured.
(5) During 300-250MW, the boiler water circulating pump (boiler water circulating pump) is started in time after the water level of the separator rises, the boiler water circulating pump is started to supply water manually, the unit enters wet operation, the water level of the separator is controlled through the pump, the circulating flow is adjusted through a BR valve (pressure reducing valve) to maintain stable water supply flow, and the discharge is reduced as much as possible. And (4) maintaining a high-low side closed state, stopping the first coal pulverizing system (the first coal pulverizing system comprises matched equipment such as a coal mill, a coal feeder and a coal powder pipe), and keeping the next two mills to run until the unit is disconnected.
(6) After the water supply is switched manually, the load is reduced by BID coal reduction. The fuel can be switched manually under 250MW, if the fuel fluctuation is large, the fuel can be switched manually after the water supply is switched manually, and the load is reduced to 200MW by reducing the fuel quantity. During which the main steam pressure remains stable.
(7) And opening the load below 200MW, continuously reducing the fuel, ensuring that the load of the unit is reduced to be below 100MW, reducing the fuel amount to be 90t/h, reducing the load to be about 50MW, opening the steam turbine in time, and maintaining the operation of the boiler. If the steam turbine is opened quickly at a high side after the brake is opened, the high side opening degree is manually adjusted in time to maintain the pressure of the main steam stable, and if the water supply fluctuation is large in the period, the water is timely cut to the electric pump to discharge water, and the steam pump is withdrawn from operation.
And (II) stopping the furnace without stopping the furnace, and performing furnace stopping operation by using a deep sliding parameter.
The reverse operation of the starting of the unit, after the steam turbine is switched on, the main steam pressure is gradually reduced through the matching control of the bypass, the coal quantity and the water supply, and the water discharging time from the splitting of the unit to the boiler is obviously shortened. The control process is as follows:
(1) the operation of the two pulverizing systems is kept, the coal quantity is gradually reduced, the heat load of the boiler is reduced, and the main steam temperature is kept stable as much as possible.
(2) The high-low side pressure is kept in an automatic mode, and the main steam pressure is gradually reduced through a high side pressure set value. The low side set value is kept unchanged at 2.0MPa, and the stable operation condition of the steam-driven draught fan is ensured. The low bypass opening degree is controlled to be not less than 30%, the high bypass opening degree is properly maintained to be larger, and the pressure reduction rate is controlled to be not more than 0.08 MPa/min. The main steam pressure is controlled to slowly decrease through the high side, the circulating water quantity of a furnace water pump is increased along with the pressure decrease, and the slow decreasing rate of the main reheat steam temperature is controlled to be not more than 0.8 ℃/min.
(3) And in the process of reducing the heat load of the boiler, the feed water flow and the water level stability of the separator are controlled by the electric pump and the BR valve in time.
(4) The total air volume is controlled to be about 1800t/h by hand, the induced draft fan is automatic, and the negative pressure of the hearth is controlled to be stable.
(5) Gradually reducing the pressure of the main steam to be below 4MPa, reducing the total fuel quantity to be below 60t/h during the period, and stopping the second powder preparation system, and gradually reducing the total fuel quantity to be 25 t/h. And after the pressure of the main steam is reduced, manually maintaining the pressure of the reheated steam to be about 2MPa by using the lower side switch in time.
(6) Stopping the coal feeder A under 4MPa, throwing four oil guns, stopping the oil guns after the coal mill is purged, and performing MFT on the boiler.
(7) And (3) closing the lower side after MFT of the boiler, closing the high side after the main steam pressure is stable, driving the induced draft fan to sweep the hearth through the residual steam, and stopping conveying the induced draft fan after 10 minutes of sweeping is finished.
And (III) controlling the cooling and pressure reduction rate to prevent the water wall from being pulled and cracked due to outage.
(1) In the rapid shutdown process of the unit, the temperature drop rate of the main steam is controlled to be not more than 1 ℃/min and the pressure of the main steam is controlled to be not more than 0.08MPa/min strictly according to the design requirements of a boiler.
(2) During 300-250MW, the boiler water circulating pump is started in time after the water level of the separator rises, the unit enters wet operation, hydrodynamic force meets requirements when the unit is in low load, and the water supply temperature is increased by the boiler water circulating mode to reduce the cooling shrinkage speed of the water wall of the boiler.
(3) The fuel quantity of the boiler is reduced at a constant speed, the total coal quantity is adjusted in time in the shutdown process of the coal mill, and the coal quantity is prevented from being greatly disturbed.
The application discloses a method for rapidly cooling an ultra-supercritical thermal power generating unit without blowing out, the load reducing time of the unit is shortened by optimizing the shutdown operation of the unit, the boiler is rapidly decompressed by deep sliding parameter shutdown operation, and the purpose of rapid cooling is achieved.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the invention without departing from the spirit and scope of the invention.
Claims (12)
1. A method for rapidly cooling an ultra-supercritical thermal power generating unit without stopping a furnace is characterized by comprising the following steps:
according to the load down-regulation requirement of the unit, the combustion strength in the boiler is reduced;
acquiring the load of the unit in real time, sequentially starting an electric feed pump, a boiler circulating pump and a manual switch-on high-low side when the load of the unit is reduced to a preset value, and switching off a steam turbine after the load is continuously reduced in place;
acquiring furnace pressure in real time, and maintaining the speed of pressure reduction and temperature reduction and reducing the furnace pressure to a preset value by stably reducing the fuel quantity and adjusting the high-low side opening degree;
acquiring the condition of the running fuel quantity in real time, if the pulverizing system is completely empty, putting an oil gun to provide fuel, and after the coal mill is completely emptied, withdrawing the oil gun, shutting down the high-low side and carrying out furnace closing;
and after the pressure relief condition is met, discharging water under pressure in the boiler.
2. The method for rapidly cooling the ultra-supercritical thermal power generating unit without stopping the furnace according to claim 1, characterized by comprising the following steps of:
step S1, completing the switching operation of the public and auxiliary systems within a certain time;
step S2, when the load of the unit is reduced to the first load, the steam source of a steam-driven water-feeding pump is switched to an auxiliary steam connecting belt;
step S3, when the load of the unit is reduced to a second load, starting a boiler circulating pump, and operating in a wet state;
step S4, when the load of the unit is reduced to a third load, the height of the unit is manually increased, the fuel quantity is reduced, and the load of the unit is continuously reduced until the steam turbine is executed to open the brake;
step S5, maintaining the furnace side combustion, and gradually reducing the main steam pressure by reducing the high and low side pressure setting;
step S6, when the pressure of the main steam is reduced to be below 4MPa, the last powder making system is shut down, an oil gun is put into the last powder making system, after the coal mill is blown empty, the oil gun is withdrawn, the boiler MFT is started, and the high-low side is closed;
step S7, after the boiler is continuously purged, executing a furnace smoldering procedure of the air and smoke system;
step S8, discharging water under pressure by the boiler when the pressure of the steam-water separator is reduced to 1 MPa;
and step S9, after the water discharge of the boiler is finished, the boiler carries out natural ventilation or starts an induced draft fan for forced ventilation.
3. The method for rapidly cooling the ultra-supercritical thermal power generating unit without shutdown as claimed in claim 2, wherein in the step S1, the time is 30 minutes, and the operations of auxiliary steam supply, heat supply and system water supplement are switched to external system supply.
4. The method for rapidly cooling the ultra-supercritical fossil power plant without stopping the furnace according to claim 2, characterized in that in step S2, when the load of the plant is reduced to 400MW, plasma stable combustion is put into the boiler.
5. The method for rapidly cooling the ultra-supercritical thermal power generating unit without shutdown as claimed in claim 2, wherein in the step S2, the first load is 380-350 MW.
6. The method for rapidly cooling the ultra-supercritical thermal power generating unit without shutdown as claimed in claim 2, wherein the second load is 300-250MW in the step S3.
7. The method for rapidly cooling the ultra-supercritical thermal power generating unit without shutdown as claimed in claim 2, wherein in step S4, when the load of the unit is reduced to 200MW, the level of the unit is gradually increased manually, the pressure of the reheater is controlled to 1.5-2MPa, when the load of the generator is not higher than 50MW, the turbine is shut down, the generator is linked, and the amount of coal after the shut down is controlled to be not more than 90 t/h.
8. The method for rapidly cooling the ultra-supercritical thermal power generating unit without stopping the furnace as claimed in claim 2, wherein in the step S5, two pulverizing systems are kept running, the coal quantity is gradually reduced to reduce the heat load of the boiler, the high-low side is kept in an automatic mode, the main steam pressure is gradually reduced by reducing the set value of the high side pressure, and the set value of the low side is kept at 2.0 MPa.
9. The method for rapidly cooling the ultra-supercritical thermal power generating unit without shutdown as claimed in claim 8, wherein in step S6, the main steam pressure is gradually reduced to below 4MPa, the total fuel amount is reduced to 25t/h, all pulverizing systems are stopped, the coal mill is emptied, the oil lance is withdrawn, the boiler MFT is turned off, and the high side and the low side are closed.
10. The method for rapidly cooling the ultra-supercritical fossil power plant without shutdown of the furnace as claimed in claim 2, wherein in the step S7, the induced draft fan is driven by the residual steam to purge the furnace chamber, the purging time is 10 minutes, and the induced draft fan is stopped after the purging is finished.
11. The method for rapidly cooling the ultra-supercritical fossil power plant without shutdown as claimed in claim 2, wherein in the step S8, the furnace-closing time is 4-5 hours.
12. The method for rapidly cooling the ultra-supercritical thermal power generating unit without shutdown as claimed in claim 2, wherein in the step S9, the time of natural ventilation is 0-12 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210514150.9A CN115059907A (en) | 2022-05-11 | 2022-05-11 | Method for rapidly cooling ultra-supercritical thermal power generating unit without stopping furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210514150.9A CN115059907A (en) | 2022-05-11 | 2022-05-11 | Method for rapidly cooling ultra-supercritical thermal power generating unit without stopping furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115059907A true CN115059907A (en) | 2022-09-16 |
Family
ID=83198247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210514150.9A Pending CN115059907A (en) | 2022-05-11 | 2022-05-11 | Method for rapidly cooling ultra-supercritical thermal power generating unit without stopping furnace |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115059907A (en) |
-
2022
- 2022-05-11 CN CN202210514150.9A patent/CN115059907A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101825005B (en) | Method for controlling the operation of high-voltage bypass in thermal generator set | |
| CN111322602B (en) | Deep peak shaving method of circulating fluidized bed boiler system | |
| CN107120149B (en) | The method and system of newly-built supercritical unit is debugged using external activated vapor | |
| CN107631288A (en) | A kind of method of fired power generating unit depth peak regulation and backheat energy-conservation | |
| CN104235819A (en) | Control method for parallel operation of steam-driven induced draft fan and electric induced draft fan of thermal power generating unit | |
| CN107246286A (en) | A kind of single reheat steam turbine of parallel high voltage cylinder | |
| CN105511420A (en) | Automatic control method of thermal power generator plant | |
| CN112814752A (en) | Rapid starting system and method for thermal generator set in medium pressure cylinder starting mode | |
| CN111678113B (en) | Environment-friendly and energy-saving supercritical CFB unit slip-stopping method | |
| CN108063459B (en) | Control method for improving deep peak regulation capability of power plant | |
| CN110529209A (en) | A kind of the solar energy optical-thermal heat reservoir and method of cogeneration units depth peak regulation | |
| CN108844058B (en) | Economizer hot water recirculation system suitable for subcritical steam drum furnace generator set and working method thereof | |
| CN115478909A (en) | Low-temperature starting control method for air turbine | |
| CN113530625A (en) | Method for rapidly reducing load after single steam pump failure of supercritical (super) critical unit configuration | |
| CN115059907A (en) | Method for rapidly cooling ultra-supercritical thermal power generating unit without stopping furnace | |
| CN111473316A (en) | Dry-state to wet-state control method for ultra-supercritical unit with furnace water circulating pump | |
| CN115342337A (en) | Flexible peak regulation control method for realizing non-stop of blowing out of CFB unit | |
| CN115127094A (en) | Safe and rapid furnace shutdown cooling method for ultra-supercritical thermal power generating unit | |
| CN212054843U (en) | Automatic start-stop control system of gas-steam combined cycle unit | |
| CN109433398B (en) | Method for saving oil during starting of boiler residual powder in intermediate storage type powder making system | |
| CN111594816B (en) | Supercritical boiler starting method based on double-layer plasma design | |
| JP3670791B2 (en) | Steam supply method and apparatus for coke dry fire extinguishing equipment | |
| CN112564101B (en) | Control method for external electricity purchase in starting and stopping process of unit | |
| CN114811963B (en) | Fire pressing method for three-waste furnace | |
| CN111023086B (en) | Method for adapting subcritical circulating fluidized bed boiler to power grid deep peak shaving |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20240627 Address after: 317600 Damaiyu Street, Yuhuan City, Taizhou City, Zhejiang Province Applicant after: Huaneng (Zhejiang) Energy Development Co.,Ltd. Yuhuan branch Country or region after: China Applicant after: Huaneng (Zhejiang) Energy Development Co.,Ltd. Address before: No. 28, Bai'an ancient, Damaiyu street, Yuhuan City, Taizhou City, Zhejiang Province, 317600 Applicant before: Huaneng (Zhejiang) Energy Development Co.,Ltd. Yuhuan branch Country or region before: China |