CN116293625A - Control method, device, equipment and storage medium for converting dry state into wet state of thermal power generating unit - Google Patents
Control method, device, equipment and storage medium for converting dry state into wet state of thermal power generating unit Download PDFInfo
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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
- F22D5/00—Controlling water feed or water level; Automatic water feeding or water-level regulators
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Abstract
The invention discloses a control method, a device, equipment and a storage medium for converting a dry state into a wet state of a thermal power generating unit, wherein the method comprises the following steps: under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage, controlling fuel quantity according to the electric load of the thermal power unit, and throwing fuel into a boiler of the thermal power unit according to a preset slowing rate; when the electric load of the thermal power generating unit is in a preset electric load range and the liquid level of a water storage tank of the thermal power generating unit is greater than or equal to the first preset liquid level height, sending a command for opening an inlet electric door of a boiler recirculation pump and a command for opening an outlet electric door of the boiler recirculation pump; and sending a command for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height. The technical scheme provided by the invention can improve the stability of the supercritical (super) unit in the process of changing the dry state into the wet state to a certain extent.
Description
Technical Field
The invention relates to the technical field of thermal power generation, in particular to a control method, a device, equipment and a storage medium for converting a dry state into a wet state of a thermal power unit.
Background
The process of converting wet state of boiler to dry state in deep peak regulating process is one special stage, and the process is one of converting circular working medium flow and one-time forced flow, and the main steam pressure, steam temperature, overheat degree, water level, etc. of boiler may be changed. If the state is changed in a failure mode, unstable working conditions such as large change of the temperature of main steam, severe fluctuation of the liquid level of the water storage tank and the like can be caused, and the operation safety of the unit can be seriously affected. In the prior art, the boiler shutdown process still adopts a traditional manual mode, and is manually MFT (Main fuel trip) when 30% BMCR (Boiler maximum continue rate) is loaded and operated in a dry state, so that a unit is shutdown, the negative pressure fluctuation of a hearth is large in the traditional shutdown method, high-temperature flame and smoke are outward generated, even a fire disaster occurs, and the water wall tube stress change is large, and the water wall is pulled apart and even bursts.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a control method, a device, equipment and a storage medium for converting a dry state of a thermal power unit into a wet state, which can improve the stability of a supercritical (super) critical unit in the process of converting the dry state into the wet state to a certain extent.
The invention provides a control method for auxiliary machine fault load reduction, which comprises the following steps: under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage, controlling fuel quantity according to the electric load of the thermal power unit, and throwing fuel into a boiler of the thermal power unit according to a preset slowing rate; when the electric load of the thermal power generating unit is in a preset electric load range and the liquid level of a water storage tank of the thermal power generating unit is greater than or equal to the first preset liquid level height, sending a command for opening an inlet electric door of a boiler recirculation pump and a command for opening an outlet electric door of the boiler recirculation pump; and sending a command for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height.
In one embodiment, the control method for changing the dry state of the thermal power generating unit into the wet state further comprises the following steps: and sending a large oil gun input instruction of the boiler under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage.
In one embodiment, the control method for changing the dry state of the thermal power generating unit into the wet state further comprises the following steps: acquiring the electric load of the thermal power generating unit, the liquid level of a water storage tank, the control state of the temperature of a middle point and the operation mode of a boiler; transmitting an allowing signal for the dry-state to wet-state operation of the thermal power generating unit under the conditions that the electric load is smaller than a preset electric load, the liquid level of the water storage tank is smaller than a third preset liquid level height, the control state of the middle point temperature is in an automatic control state, and the boiler operation mode is in a dry-state operation; the permission signal is used for representing that the current thermal power generating unit enters a dry state to wet state operation stage.
In one embodiment, the control method for changing the dry state of the thermal power generating unit into the wet state further comprises the following steps: sending 361 valve opening instructions of the thermal power generating unit under the condition that the liquid level of the water storage tank reaches a second preset liquid level height; wherein the 361 valve opening command includes a preset opening of the 361 valve; monitoring the water flow speed of a 360 valve of the thermal power generating unit; and under the condition that the water flow speed reaches the preset flow speed, adjusting the state of the 361 valve of the thermal power generating unit to an automatic control state.
In one embodiment, the control method for changing the dry state of the thermal power generating unit into the wet state further comprises the following steps: if the difference between the opening of the 361 valve and the preset opening is larger than a preset threshold value, the state of the 361 valve of the thermal power generating unit is adjusted to be a manual control state; and/or if the difference value between the liquid level of the water storage tank and the liquid level of the preset water storage tank is greater than a preset threshold value, adjusting the state of the 361 valve of the thermal power generating unit to a manual control state.
In one embodiment, the thermal power generating unit comprises a water storage tank liquid level signal quality judging module, and the control method for converting the dry state of the thermal power generating unit into the wet state further comprises the following steps: if the liquid level of the water storage tank is judged to be poor in signal quality by the liquid level signal judging module of the water storage tank, the state of a 361 valve of the thermal power generating unit is adjusted to be a manual control state; the signal judging module is used for judging that the signal quality of the liquid level signal of the water storage tank is poor under the condition that the signal quality of the liquid level signal of the water storage tank is smaller than or equal to a preset mass fraction.
In one embodiment, in the step of controlling the amount of fuel according to the electric load of the thermal power plant to a preset slow down rate and charging the fuel into the boiler of the thermal power plant, the method comprises: determining a target fuel amount of a boiler of the thermal power generating unit at the next moment according to the current fuel amount and the preset slowing rate; determining a target water supply amount required by the thermal power generating unit at the next moment according to the target fuel amount; and throwing fuel into a boiler of the thermal power generating unit according to the target fuel quantity, and supplying water to the thermal power generating unit according to the target water supply quantity.
In one embodiment, the control method for changing the dry state of the thermal power generating unit into the wet state further comprises the following steps: and controlling the opening of a steam turbine regulating door of the thermal power unit so that the main steam pressure of the thermal power unit is within a preset pressure range.
The invention further provides a control device for converting a dry state into a wet state of a thermal power unit, which comprises the following components: the fuel slowing-down input unit is used for controlling the fuel quantity according to the electric load of the thermal power unit and inputting the fuel into a boiler of the thermal power unit according to a preset slowing-down rate under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage; the first instruction sending unit is used for sending an instruction for opening an inlet electric door of the boiler recirculation pump and an instruction for opening an outlet electric door of the boiler recirculation pump when the electric load of the thermal power unit is in a preset electric load range and the liquid level of a water storage tank of the thermal power unit is greater than or equal to a first preset liquid level; and the second instruction sending unit is used for sending an instruction for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height.
When the boiler of the thermal power unit is in a state of running, the boiler fuel burning has larger hysteresis, the feeding of the boiler fuel is gently reduced, the inlet and outlet electric doors of the boiler recirculation pump are timely opened, the recirculation pump is started under the condition that the liquid level of the boiler boiling water storage tank reaches the preset liquid level height, the cooling flow of the boiler recirculation pump can be ensured, vaporization is prevented, and the main steam temperature, the main steam pressure and the unit output of the thermal power unit are prevented from greatly changing, so that the steady transition of the dry state to wet state process of the thermal power unit is avoided.
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The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and should not be construed as limiting the invention in any way, in which:
FIG. 1 is a schematic diagram showing steps of a method for controlling a dry state to a wet state of a thermal power generating unit according to an embodiment of the present disclosure;
FIG. 2 illustrates a schematic diagram of a once-through boiler start-up system in one embodiment of the present disclosure;
FIG. 3 shows a logic judgment diagram of steady burning of a large oil gun put into a boiler before a dry state is changed into a wet state in one embodiment of the present disclosure;
FIG. 4 is a logic judgment diagram showing the start of the furnace water circulation pump by opening the front and rear electric doors of the furnace water circulation pump during the transition of the R dry state to the wet state in one embodiment of the present disclosure;
FIG. 5 illustrates a logic diagram of automatic and manual control switching of 361 valves after opening 361 valves in one embodiment of the present disclosure
FIG. 6 is a schematic diagram of a control device for converting a dry state to a wet state of a thermal power plant according to an embodiment of the disclosure;
fig. 7 shows a schematic structural diagram of an electronic device in one embodiment of the present disclosure.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present disclosure, but not all embodiments. All other embodiments, which can be made by those skilled in the art without the inventive effort, based on the embodiments in this disclosure are intended to be within the scope of this disclosure.
In recent years, along with the continuous improvement of the proportion of renewable energy sources in the energy source structure of China, the capacity of the power grid for absorbing renewable energy sources is improved, but the contribution of renewable energy sources to the power grid peak shaving is limited, so that the importance of the coal generator set with good peak shaving capacity in the power grid peak shaving process is also more and more obvious. The coal motor is formed into the basic energy for power grid flexibility peak regulation under the double pressure of the power grid for absorbing a large amount of renewable energy and the surplus capacity of the coal motor group, and the difficult task of power grid peak regulation is born. At present, the peak regulation form of the coal-fired unit is continuously changed under the influence of larger peak-valley difference of the power grid load, and particularly, the ultra-basic peak regulation range of the coal-fired unit is normalized, so that the operation mode of deep peak regulation of the coal-fired unit is gradually formed.
In order to successfully finish the power-assisted national carbon peak and carbon neutralization targets, the national emission and modification commission and the energy bureau issue an embodiment of modification and upgrading of national coal electric motor sets in 2021, and clearly propose that the peak regulating capacity of the pure condensation working condition of a newly-built coal electric motor set and an active service set after the flexibility modification is required to reach 35% Pe, and the heat and power cogeneration heating set reaches 40% Pe. However, at present, most coal motor sets coordinate control strategies are designed and debugged under the working condition of more than 50% Pe, so that the requirements on deep peak shaving of the sets, particularly the super (super) critical sets, are difficult to meet, and the dry and wet states of the once-through boiler are converted into the difficulties of deep peak shaving. And certain areas are benefit of competing for the deep peak shaving of the unit, the feasibility of low-load stable combustion operation of the unit is researched, and the limit value of the deep peak shaving of the unit is continuously refreshed from 35% Pe to 25% Pe.
The process of converting wet state of boiler to dry state in deep peak regulating process is one special stage, and the process is one of converting circular working medium flow and one-time forced flow, and the main steam pressure, steam temperature, overheat degree, water level, etc. of boiler may be changed. If the state transition failure causes unstable working conditions such as large change of the temperature of main steam, severe fluctuation of the liquid level of a water storage tank and the like, the running safety of a unit can be seriously influenced, the invention designs a control strategy for converting the wet state of the deep peak regulation super (super) critical direct current boiler into the dry state, and various important parameters of the boiler state transition are stable in the practical engineering application, so that a good application effect is obtained.
Taking a certain 1000MW ultra-supercritical thermal power generating unit as an example, the steam-water system of the coal-fired unit is configured into two steam water supply pumps with 50% BMCR and one electric water supply pump with 30% BMCR, the main steam temperature is adjusted by adjusting the water-coal ratio and two-stage desuperheating water, and the reheat steam temperature is adjusted by adjusting the swing angle of a burner and the accident desuperheating water. The unit starting system is provided with a furnace water circulating pump, the furnace water circulating pump is connected in series with a main water supply pipeline, and inlet working media are respectively from a main water supply pipeline and a descending pipe. In the starting process of the unit, along with the increase of the load, the water supply flow is increased, the water supply proportion of the working medium at the inlet of the furnace water circulating pump is also gradually increased, and the net suction pressure head and the cooling flow of the circulating pump are always maintained.
Referring to fig. 1, a method for controlling a dry state to a wet state of a thermal power generating unit according to an embodiment of the present disclosure may include the following steps.
S110: under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage, controlling the fuel quantity according to the electric load of the thermal power unit, and throwing the fuel into a boiler of the thermal power unit according to a preset slowing rate.
In the embodiment, as the supercritical (supercritical) direct-current furnace has no obvious steam-water boundary, when the fuel water supply proportion is out of order, the running state of the boiler can be converted into a dry state and a wet state, and the load value and the steam parameter of the unit have no strict corresponding relation in the conversion process. For the supercritical once-through boiler, in order to ensure that the water cooling wall of the down tube of the boiler has enough cooling water quantity when the unit is in low load, the water cooling wall is not over-heated, the water supply flow of the water cooling wall is not lower than the lowest flow of the boiler, and meanwhile, the separation capacity of a starting separator of the boiler is also required to be considered, so that the main steam temperature is greatly reduced due to the water inlet of the superheater, and the dry-state to-wet-state process is usually carried out at 30%Pe of the unit load. When the thermal power generating unit is operated in a dry state to a wet state, the unit load value is 300 MW-265 MW, and main parameters such as unit load, steam pressure, water supply flow and the like are kept stable before the thermal power generating unit is operated in the wet state.
Referring to fig. 2, in the present embodiment, after the direct current boiler system is started, under normal working conditions, the water supply channel pipe goes back and forth, passes through the economizer (1) and the water-cooled wall (2) to the starting separators (3 and 4), and when in dry operation, the water supply to the starting separators (3 and 4) in the figure is main steam with high temperature and high pressure, and works through the superheaters (8 and 10) and the desuperheater (9) to the steam turbine (11); when the boiler runs in a dry state to a wet state, a boiler water circulating pump (6) is started when a liquid level of 5m is displayed in a water storage tank (5), meanwhile, a valve 361 (12) in the figure is slowly opened to 5% until the flow rate of a valve 360 (7) is 250t/h, and the valve of the valve 361 (12) is automatically regulated.
In the embodiment, the fuel quantity is slowly reduced, and when the boiler is in a transition state operation, the fuel reduction process is smoothly carried out due to the fact that the combustion of the boiler fuel has larger hysteresis, and under the condition that the coal quality is kept unchanged, the fuel can be reduced according to the fuel quantity of 4t/h corresponding to the 10MW load quantity. After the transition is completed, the fuel amount is reduced by about 20t/h according to the operation experience value.
In the embodiment, the air quantity can be correspondingly reduced through the air-coal ratio so as to reduce the heat load of the boiler, the load of the unit is continuously reduced, and the superheat degree is slowly reduced.
S120: and sending an instruction for opening the electric door of the inlet of the boiler recirculation pump and an instruction for opening the electric door of the outlet of the boiler recirculation pump under the condition that the electric load of the thermal power unit is in a preset electric load range and the liquid level of the water storage tank of the thermal power unit is greater than or equal to the first preset liquid level.
In the embodiment, the water supply main path is switched to the bypass operation in the process of changing the boiler operation of the thermal power generating unit from the dry state to the wet state or before the boiler operation of the thermal power generating unit is changed, and when the state is changed, the water supply bypass valve is switched to the automatic state, and the water supply amount is maintained at about 950 t/h. Therefore, when the thermal power unit is in a state of running (i.e. in a state of running in a dry state and a wet state), the inlet electric door of the boiler recirculation pump and the outlet electric door of the boiler recirculation pump of the thermal power unit are timely opened. Specifically, for example, when the electric load value of the thermal power unit is between 260MW and 302MW, the thermal power unit sends a dry state to wet state permission signal, and the liquid level of the water storage tank is greater than 0.5m, the thermal power unit is judged to be in a dry state to wet state operation transition region at the moment, then an instruction for opening an electric door at the inlet of the boiler recirculation pump and an instruction for opening an electric door at the outlet of the boiler recirculation pump are sent, and electric doors at the front and back of the boiler water circulation pump are opened.
S130: and sending a command for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height.
In this embodiment, when the electric load of the thermal power generating unit is within the preset charge range and the liquid level of the water storage tank reaches the second liquid level, a command to start the recirculation pump is sent. Specifically, for example, after the liquid level of the boiler water storage tank rises to the normal water level of 5-7 m, the recirculation pump is started, so that the cooling flow of the boiler recirculation pump is ensured in the process, vaporization is prevented, and the boiler water is recovered from the aspect of energy conservation, so that heat damage is reduced.
Referring to fig. 3, in the present embodiment, when the thermal power generating unit is running in a dry state to a wet state, and the electrical load of the thermal power generating unit is between 260MW and 302MW, and the liquid level of the water storage tank is greater than 0.5m, an instruction for opening the front and rear electric doors of the furnace water circulation pump is issued, and the front and rear electric doors of the furnace water circulation pump are opened. Meanwhile, under the condition that the thermal power generating unit is in dry state to wet state operation, and the electric load of the thermal power generating unit is between 260MW and 302MW, when the liquid level of the water storage tank reaches more than 5m, a command for starting the furnace water circulating pump is sent out.
In one embodiment, the method for controlling the dry state to the wet state of the thermal power generating unit can further comprise: and sending a large oil gun input instruction of the boiler under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage.
In the embodiment, the boiler combustion of the thermal power generating unit is stabilized by sending a large oil gun input instruction under the condition that the thermal power generating unit is detected to be about to enter a dry state to a wet state. If the load of the unit is reduced below the minimum stable combustion load, the number of the stable combustion guns is properly increased, and stable combustion in the hearth is maintained. The dry-wet state conversion of the boiler is a stable transition process, and whether the switching process is successful or not is judged by the superheat degree, the water level of the water storage tank, the pressure of main steam and the temperature of the main steam. And the great changes of the main steam temperature, the main steam pressure and the unit output are avoided in the switching process.
In one embodiment, the method for controlling the dry state to the wet state of the thermal power generating unit can further comprise: acquiring the electric load of the thermal power generating unit, the liquid level of a water storage tank, the control state of the temperature of a middle point and the operation mode of a boiler; transmitting an allowing signal for the dry-state to wet-state operation of the thermal power generating unit under the conditions that the electric load is smaller than a preset electric load, the liquid level of the water storage tank is smaller than a third preset liquid level height, the control state of the middle point temperature is in an automatic control state, and the boiler operation mode is in a dry-state operation; the permission signal is used for representing that the current thermal power generating unit enters a dry state to wet state operation stage.
Referring to fig. 4, in the present embodiment, by the thermal power unit load being less than 305MW, the water storage tank level being less than 1m, the intermediate point temperature being in an automatic control state, the boiler operating in a dry mode, these four condition phases determine that the boiler is about to start to turn, and then issue a large oil gun command for feeding the boiler through a control strategy.
In one embodiment, the method for controlling the dry state to the wet state of the thermal power generating unit can further comprise: sending 361 valve opening instructions of the thermal power generating unit under the condition that the liquid level of the water storage tank reaches a second preset liquid level height; wherein the 361 valve opening command includes a preset opening of the 361 valve; monitoring the water flow speed of a 360 valve of the thermal power generating unit; and under the condition that the water flow speed reaches the preset flow speed, adjusting the state of the 361 valve of the thermal power generating unit to an automatic control state.
In this embodiment, the opening of the 361 valve is slowly opened to the preset opening by the enhanced soft operator by determining that the liquid level of the water storage tank reaches the second preset liquid level. Under the condition that the flow rate of water flowing through a 360 valve of the thermal power generating unit reaches 250t/h, a 361 valve throwing automatic adjustment request is sent to the enhanced soft manual operator, and the 361 valve throwing automatic operation is carried out. Specifically, for example, it is determined that the liquid level of the water storage tank has reached more than 5m (the second preset liquid level height), the enhanced soft manual operator slowly opens the 361 valve to an opening degree of 5% (the preset opening degree of the 361 valve), it is determined that the flow rate of the water flow through the 360 valve has reached more than 250t/h, and then a request for automatic adjustment of the 361 valve is issued to the enhanced soft manual operator, and the 361 valve is put into operation automatically.
In one embodiment, the method for controlling the dry state to the wet state of the thermal power generating unit can further comprise: if the difference between the opening of the 361 valve and the preset opening is larger than a preset threshold value, the state of the 361 valve of the thermal power generating unit is adjusted to be a manual control state; and/or if the difference value between the liquid level of the water storage tank and the liquid level of the preset water storage tank is greater than a preset threshold value, adjusting the state of the 361 valve of the thermal power generating unit to a manual control state.
In the present embodiment, in some cases, the difference between the opening degree of the 361 valve and the opening degree of the valve in the 361 valve opening instruction exceeds a preset threshold due to the influence of factors such as an error of an operator or an uncontrolled system. Or under the condition that the difference value between the liquid level value of the water storage tank and the liquid level of the preset water storage tank exceeds the preset threshold value, the thermal power unit is prevented from being failed due to the water supply amount. In order to prevent the steam temperature of the superheater and the reheater from falling too quickly and properly closing the desuperheating water regulating valve, the boiler water supply flow rate should be kept in the transition process, the water supply flow rate is ensured not to be lower than a protection fixed value, the unit should not stop because of low water supply flow rate, and the control mode of 361 needs to be temporarily adjusted to a manual control mode.
Specifically, for example, please refer to fig. 5. After the liquid level PV value of the water storage tank is filtered in advance and in delay, the liquid level PV value is compared with the SP value of the liquid level of the water storage tank, the liquid level PV value is sent to an enhanced EPID control logic block for PID operation, an operating instruction is sent to a valve opening instruction of a boiler 361 through an enhanced soft manual logic block, the valve is endowed with a corresponding opening degree, meanwhile, the difference between the liquid level PV value of the water storage tank and the SP value is judged to be more than 2.5m, the difference between the valve opening degree feedback of the boiler 361 and the opening degree instruction is 15%, when any two conditions occur, the valve adjustment is automatically released, the valve 361 enters a manual adjustment mode, and the valve adjustment manual mode display is displayed.
In this embodiment, in the process of changing the dry state to the wet state, the start system of the boiler drains water to the condenser, so as to reduce the influence of the drain water on the vacuum of the condenser, and the opening of the 361 valve should be maintained during the wet state operation of the boiler, so as to avoid the influence of the excessive drain water on the vacuum of the condenser.
In one embodiment, the thermal power generating unit comprises a water storage tank liquid level signal quality judging module, and the control method for converting the dry state of the thermal power generating unit into the wet state of the thermal power generating unit can further comprise: if the liquid level of the water storage tank is judged to be poor in signal quality by the liquid level signal judging module of the water storage tank, the state of a 361 valve of the thermal power generating unit is adjusted to be a manual control state; the signal judging module is used for judging that the signal quality of the liquid level signal of the water storage tank is poor under the condition that the signal quality of the liquid level signal of the water storage tank is smaller than or equal to a preset mass fraction.
In this embodiment, please refer to fig. 5. If the abnormal working condition occurs in the 361 valve adjusting process, and the quality of the measurement of the liquid level PV value of the water storage tank is judged to be bad, the 361 valve adjusting automation is also released, and the 361 valve enters a manual adjusting mode.
In one embodiment, in the step of controlling the amount of fuel according to the electric load of the thermal power plant to a preset slow down rate and charging the fuel into the boiler of the thermal power plant, the method may include: determining a target fuel amount of a boiler of the thermal power generating unit at the next moment according to the current fuel amount and the preset slowing rate; determining a target water supply amount required by the thermal power generating unit at the next moment according to the target fuel amount; and throwing fuel into a boiler of the thermal power generating unit according to the target fuel quantity, and supplying water to the thermal power generating unit according to the target water supply quantity.
In the embodiment, in the process of dry-state to wet-state operation of the thermal power generating unit, the water-cooled wall down tube and the back wall of the boiler may generate steam-water two-phase flow, and temperature deviation or temperature overrun of the down tube wall may be caused by uneven hydrodynamic force. In the process, the stability of fuel quantity and water supply quantity is maintained as much as possible, the operation time of the area is shortened as much as possible, the water-coal ratio is controlled to be 7.5-8, and the occurrence of dry-wet state alternating working conditions caused by large fluctuation of water supply flow and fuel quantity is avoided.
In one embodiment, the method for controlling the dry state to the wet state of the thermal power generating unit can further comprise: and controlling the opening of a steam turbine regulating door of the thermal power unit so that the main steam pressure of the thermal power unit is within a preset pressure range.
In the embodiment, the main steam pressure of the boiler of the thermal power unit is controlled to be maintained at about 10MPa in the transition process, and gradually decreases along with the decrease of the fuel quantity, and at the moment, the current main steam pressure can be maintained in a mode of properly closing a main machine valve through a control strategy, so that the main steam pressure is prevented from decreasing along with the decrease of the load of the unit. Meanwhile, the descending amplitude of the unit load value is not suitable to be too large, the correction effect of the unit load on the liquid level of the water storage tank is maintained, the main vapor pressure is reduced, the mode of closing the small regulating valve is realized in the original DEH logic, the control strategy design increases the speed limit of the descending of the load value, and the overlarge descending of the load is prevented.
In a specific embodiment, taking a 1000MW ultra-supercritical unit as an example, in the deep peak regulation process of the unit, the boiler is operated in a wet state from a dry state operation mode, the main process is that the load of the boiler is reduced to below 30% Pe, the main steam pressure is reduced to about 10MPa, the fuel amount is slowly reduced through a control strategy, the liquid level of a boiler water storage tank is increased, and the boiler is operated in a wet state.
When the unit load is reduced to 30% Pe in the process of changing the dry running of the boiler to the wet running, the boiler maintains 3 pulverizing systems to run, if the unit load is continuously reduced, one pulverizing system should be used for outputting less, the water supply flow is maintained at 950t/h, and a bottom layer large oil gun is added to stabilize the boiler to burn if necessary. In the process, the coal feeding amount of the pulverizing system is gradually reduced, the liquid level of the water storage tank is gradually increased, meanwhile, the 361 valve is slowly opened, and when the liquid level of the water storage tank reaches about 5m, the 361 valve is automatically thrown, and the current liquid level value of the water storage tank is maintained. It should be noted that in this process, if the unit load falls below the minimum steady burning load, the number of steady burning guns to be put into is increased appropriately to maintain steady burning in the furnace. The dry-wet state conversion of the boiler is a stable transition process, and whether the switching process is successful or not is judged by the superheat degree, the water level of the water storage tank, the pressure of main steam and the temperature of the main steam. And the great changes of the main steam temperature, the main steam pressure and the unit output are avoided in the switching process.
In addition, in the process of changing the dry state into the wet state, the starting system of the boiler drains water to the condenser, so that the influence of the drainage water on the vacuum of the condenser is reduced, and the opening of the 361 valve is maintained when the boiler is in wet state operation, so that the influence of the excessive drainage water on the vacuum of the condenser is avoided. When the conversion area operates, the water-cooled wall down pipe and the back wall of the boiler can generate steam-water two-phase flow, and the temperature deviation or the temperature overrun of the down pipe wall can be caused by uneven hydrodynamic force. In the process, the stability of fuel quantity and water supply quantity is maintained as much as possible, the operation time of the area is shortened as much as possible, the water-coal ratio is controlled to be 7.5-8, and the occurrence of dry-wet state alternating working conditions caused by large fluctuation of water supply flow and fuel quantity is avoided.
Because the boiler transition process is a special working condition in the operation process, all main parameters can be changed, and if the water-coal ratio and the main steam pressure are controlled improperly, all main parameters such as the main steam pressure, the main steam temperature, the superheat degree and the like can be caused to fluctuate severely, so that the safe operation of the unit is affected. Aiming at the characteristics of dry-wet state conversion of the supercritical (supercritical) direct-current boiler, various risks possibly occurring in the conversion process are comprehensively considered, a wet-state-to-dry-state control strategy of the deep peak regulation supercritical (supercritical) thermal power unit is formulated, the whole process automation of dry-state-to-wet-state operation is realized, the operation intensity of operators is reduced, the automation level of the unit is improved, the process of converting the wet state of the boiler into the dry state operation is rapidly completed under the deep peak regulation working condition, and the working condition that main parameters are unstable due to improper adjustment in the conversion process is avoided.
Referring to fig. 6, an embodiment of the present disclosure further provides a control device for converting a dry state into a wet state of a thermal power generating unit, where the control device for converting a dry state into a wet state of a thermal power generating unit may include: the fuel slow down input unit, the first instruction sending unit and the second instruction sending unit.
And the fuel slowing-down input unit is used for controlling the fuel quantity to be input into a boiler of the thermal power unit according to a preset slowing rate according to the electric load of the thermal power unit under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage.
The first command sending unit is used for sending a command for opening an electric door at the inlet of the boiler recirculation pump and a command for opening an electric door at the outlet of the boiler recirculation pump when the electric load of the thermal power generating unit is in a preset charge range and the liquid level of the water storage tank of the thermal power generating unit is greater than or equal to a first preset liquid level.
And the second instruction sending unit is used for sending an instruction for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height.
Specific functions and effects realized by the control device for converting the dry state to the wet state of the auxiliary thermal power unit can be contrasted and explained with reference to other embodiments in the specification, and are not repeated here. All or part of each module in the control device for converting the dry state of the thermal power generating unit into the wet state can be realized by software, hardware and the combination thereof. The modules can be embedded in hardware or independent of a processor in the computer device, or can be stored in a memory in the computer device in a software mode, so that the processor can call and execute the operations corresponding to the modules.
Referring to fig. 7, an embodiment of the disclosure further provides an electronic device, where the electronic device includes a processor and a memory, and the memory is configured to store a computer program, and when the computer program is executed by the processor, the method for controlling the dry state to the wet state of the thermal power generating unit is implemented.
The processor may be a central processing unit (Central Processing Unit, CPU). The processor may also be any other general purpose processor, digital signal processor (Digital Signal Processor, DSP), application specific integrated circuit (Application Specific Integrated Circuit, ASIC), field programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof.
The memory, as a non-transitory computer readable storage medium, may be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as program instructions/modules, corresponding to the methods in embodiments of the present invention. The processor executes various functional applications of the processor and data processing, i.e., implements the methods of the method embodiments described above, by running non-transitory software programs, instructions, and modules stored in memory.
The memory may include a memory program area and a memory data area, wherein the memory program area may store an operating system, at least one application program required for a function; the storage data area may store data created by the processor, etc. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some implementations, the memory optionally includes memory remotely located relative to the processor, the remote memory being connectable to the processor through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The embodiment of the disclosure also provides a computer readable storage medium for storing a computer program, which when executed by a processor, implements the method for controlling the dry state to the wet state of the thermal power generating unit.
Those skilled in the art will appreciate that implementing all or part of the processes in the methods of the embodiments may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise processes of embodiments of the methods as described herein. Any reference to memory, storage, database, or other medium used in the implementations provided herein can include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, or the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory. By way of illustration, and not limitation, RAM can be in the form of a variety of forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), and the like.
It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The various embodiments of the present disclosure are described in a progressive manner. The different embodiments focus on describing different portions compared to other embodiments. Those skilled in the art will appreciate, after reading the present specification, that a plurality of embodiments of the present specification and a plurality of technical features disclosed in the embodiments may be combined in a plurality of ways, and for brevity of description, all of the possible combinations of the technical features in the embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, it should be considered as the scope described in the present specification.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.
The various embodiments in this specification are themselves focused on differing portions from other embodiments, and the various embodiments may be explained in cross-reference to one another. Any combination of the various embodiments in the present specification is encompassed by the disclosure of the present specification by a person of ordinary skill in the art based on general technical knowledge.
The foregoing is merely illustrative of the present invention and is not intended to limit the scope of the claims. Various modifications and changes may occur to those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which fall within the spirit and principles of the present invention are intended to be included within the scope of the claims.
Claims (11)
1. The method for controlling the dry state to the wet state of the thermal power generating unit is characterized by comprising the following steps of:
under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage, controlling fuel quantity according to the electric load of the thermal power unit, and throwing fuel into a boiler of the thermal power unit according to a preset slowing rate;
when the electric load of the thermal power generating unit is in a preset electric load range and the liquid level of a water storage tank of the thermal power generating unit is greater than or equal to the first preset liquid level height, sending a command for opening an inlet electric door of a boiler recirculation pump and a command for opening an outlet electric door of the boiler recirculation pump;
and sending a command for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height.
2. The method according to claim 1, wherein the method further comprises:
and sending a large oil gun input instruction of the boiler under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage.
3. The method according to claim 2, wherein the method further comprises:
acquiring the electric load of the thermal power generating unit, the liquid level of a water storage tank, the control state of the temperature of a middle point and the operation mode of a boiler;
transmitting an allowing signal for the dry-state to wet-state operation of the thermal power generating unit under the conditions that the electric load is smaller than a preset electric load, the liquid level of the water storage tank is smaller than a third preset liquid level height, the control state of the middle point temperature is in an automatic control state, and the boiler operation mode is in a dry-state operation; the permission signal is used for representing that the current thermal power generating unit enters a dry state to wet state operation stage.
4. The method according to claim 1, wherein the method further comprises:
sending 361 valve opening instructions of the thermal power generating unit under the condition that the liquid level of the water storage tank reaches a second preset liquid level height; wherein the 361 valve opening command includes a preset opening of the 361 valve;
monitoring the water flow speed of a 360 valve of the thermal power generating unit;
and under the condition that the water flow speed reaches the preset flow speed, adjusting the state of the 361 valve of the thermal power generating unit to an automatic control state.
5. The method according to claim 4, wherein the method further comprises:
if the difference between the opening of the 361 valve and the preset opening is larger than a preset threshold value, the state of the 361 valve of the thermal power generating unit is adjusted to be a manual control state;
and/or if the difference value between the liquid level of the water storage tank and the liquid level of the preset water storage tank is greater than a preset threshold value, adjusting the state of the 361 valve of the thermal power generating unit to a manual control state.
6. The method of claim 4, wherein the thermal power plant includes a tank level signal quality determination module, the method further comprising:
if the liquid level of the water storage tank is judged to be poor in signal quality by the liquid level signal judging module of the water storage tank, the state of a 361 valve of the thermal power generating unit is adjusted to be a manual control state; the signal judging module is used for judging that the signal quality of the liquid level signal of the water storage tank is poor under the condition that the signal quality of the liquid level signal of the water storage tank is smaller than or equal to a preset mass fraction.
7. The method according to claim 1, wherein in the step of controlling the amount of fuel to a preset rate of deceleration according to the electric load of the thermal power plant, the step of feeding fuel into the boiler of the thermal power plant comprises:
determining a target fuel amount of a boiler of the thermal power generating unit at the next moment according to the current fuel amount and the preset slowing rate;
determining a target water supply amount required by the thermal power generating unit at the next moment according to the target fuel amount;
and throwing fuel into a boiler of the thermal power generating unit according to the target fuel quantity, and supplying water to the thermal power generating unit according to the target water supply quantity.
8. The method according to claim 1, wherein the method further comprises:
and controlling the opening of a steam turbine regulating door of the thermal power unit so that the main steam pressure of the thermal power unit is within a preset pressure range.
9. The utility model provides a controlling means of thermal power generating unit dry state changes wet state which characterized in that, thermal power generating unit dry state changes wet state's controlling means includes:
the fuel slowing-down input unit is used for controlling the fuel quantity according to the electric load of the thermal power unit and inputting the fuel into a boiler of the thermal power unit according to a preset slowing-down rate under the condition that the thermal power unit is monitored to enter a dry state to wet state operation stage;
the first instruction sending unit is used for sending an instruction for opening an inlet electric door of the boiler recirculation pump and an instruction for opening an outlet electric door of the boiler recirculation pump when the electric load of the thermal power unit is in a preset electric load range and the liquid level of a water storage tank of the thermal power unit is greater than or equal to a first preset liquid level;
and the second instruction sending unit is used for sending an instruction for starting the recirculation pump under the condition that the liquid level of the water storage tank reaches a second preset liquid level height.
10. An electronic device, characterized in that the electronic device arrangement comprises a processor and a memory for storing a computer program which, when executed by the processor, implements the method according to any of claims 1 to 8.
11. A computer readable storage medium for storing a computer program which, when executed by a processor, implements the method of any one of claims 1 to 8.
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