Method and device for controlling process of converting dry state into wet state of once-through boiler

Abstract

The invention provides a once-through boiler dry-to-wet process control method and device, and relates to the technical field of automatic control. The method comprises the steps that if it is determined that dry-state-to-wet-state conversion of the once-through boiler meets a front control condition, preset batch water supply flow is periodically obtained, the water level of a water storage tank is monitored, and if it is determined that the water level of the water storage tank is larger than a boiler water pump starting allowable water level, a supercooled water electric valve is opened; starting a boiler water circulating pump, and opening a boiler water pump outlet electric shut-off valve and a boiler water pump outlet adjusting valve when a first preset duration is reached so as to control and continuously monitor the water level of the water storage tank; if it is determined that the water level of the water storage tank is in the stable state and the boiler water circulating pump operates normally, a prompt message indicating that dry-state-to-wet-state conversion of the once-through boiler is completed is generated so that it can be manually confirmed that dry-state-to-wet-state conversion of the once-through boiler is completed. The device executes the method. According to the method and device provided by the embodiment of the invention, it can be guaranteed that the process of converting the dry state into the wet state of the once-through boiler is smoothly carried out.

Description

Technical Field

[0001] The present invention relates to the field of automatic control technology, and in particular to a method and device for controlling a dry-state to wet-state process of a once-through boiler. Background Art

[0002] With the increasing proportion of renewable energy in the power grid, thermal power plants are generally facing the need for deep peak shaving. Currently, supercritical and ultra-supercritical units can generally achieve deep peak shaving at 30% BMCR. However, with the continued development of renewable energy, these units will also face the need for deep peak shaving at 20% BMCR or even 20% THA. To meet this demand for deep peak shaving at 20% BMCR or 20% THA, supercritical and ultra-supercritical boilers generally have two methods: dry deep shaving or wet deep shaving. Dry 20% BMCR or 20% THA often exceeds the boiler's hydrodynamically safe operating range, resulting in significantly increased waterwall temperature deviations. Wet 20% BMCR or 20% THA can be achieved by discharging some hot water or recovering it through a boiler water recirculation pump. This increased feedwater rate expands the boiler's hydrodynamically safe load range, but there is a need for automated switching, specifically, converting dry to wet operation for once-through boilers.

[0003] The existing technology achieves automated transition by changing the amount of coal, which actually causes changes in the power generation during the transition process. If the unit is put into coordinated control mode, it will cause changes in the main steam pressure, and then lead to changes in the boiler coal feed amount, forming a process of reducing coal-automatically adding coal-reducing coal-automatically adding coal, affecting the smooth progress of the transition process and prolonging the transition time. Summary of the Invention

[0004] In response to the problems in the prior art, an embodiment of the present invention provides a method and device for controlling the dry-state to wet-state process of a once-through boiler, which can at least partially solve the problems in the prior art.

[0005] In one aspect, the present invention provides a method for controlling a dry-to-wet state transition process of a once-through boiler, comprising:

[0006] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0007] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0008] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0009] Among them, it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, including:

[0010] Determining the load to be a dry minimum load; the water flow rate in the dry state of the dry minimum load is greater than the sum of the Bunsen flow rate and the margin;

[0011] Start the transition timer, open the electric valve behind the regulating valve, close the start-up system warm-up valve, close the boiler water pump warm-up valve, and open the boiler water pump recirculation valve;

[0012] Controlling the superheat degree at the outlet of the steam-water separator to a first preset temperature, switching the main steam pressure at the outlet of the steam-water separator to constant pressure control, and maintaining the load stable for a second preset time;

[0013] Release the automatic control of the superheat temperature at the steam-water separator outlet.

[0014] Wherein, the electric valve after opening the regulating valve comprises:

[0015] At the same time, open the electric valve behind the No. 1 361 regulating valve and the electric valve behind the No. 2 361 regulating valve.

[0016] The periodic acquisition of the preset batch water flow rate includes:

[0017] Determine the preset total feed water flow rate required to increase the dry state of the once-through boiler to the wet state, and determine the preset batch feed water flow rates for batch supply based on the preset total feed water flow rate;

[0018] The preset batch water supply flow is imported one by one in batches according to the preset time period until the preset total water supply flow is fully imported.

[0019] The method for controlling the dry-state to wet-state transition process of a once-through boiler further includes:

[0020] If it is determined that the boiler water circulation pump fails to start or does not exist, open the No. 1 361 regulating valve and the No. 2 361 regulating valve for automatic control to automatically inject water from the water storage tank into the atmospheric expansion tank;

[0021] Start a drain pump, and if monitoring determines that the water level in the water storage tank is stable, the water level in the atmospheric expansion tank is stable, and the drain pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct-current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct-current boiler has been completed.

[0022] The method for controlling the dry-state to wet-state transition process of a once-through boiler further includes:

[0023] Start a drain pump through the active / standby switchover mode.

[0024] In one aspect, the present invention provides a dry-to-wet state process control device for a once-through boiler, comprising:

[0025] The first control unit is configured to periodically obtain a preset batch water flow rate and monitor the water level in the water storage tank if it is determined that the dry-state to wet-state transition of the once-through boiler satisfies the pre-control condition, and to open the subcooling water electric valve if it is determined that the water level in the water storage tank is greater than the boiler water pump start-up allowable water level;

[0026] The second control unit is used to start the boiler water circulation pump and open the electric shut-off valve and the boiler water pump outlet regulating valve at the first preset time to control and continuously monitor the water level of the water storage tank;

[0027] The third control unit is used to generate a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed if it is determined that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, so as to provide manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0028] In another aspect, an embodiment of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the following method is implemented:

[0029] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0030] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0031] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0032] An embodiment of the present invention provides a computer-readable storage medium, including:

[0033] The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0034] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0035] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0036] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0037] An embodiment of the present invention further provides a computer program product, comprising a computer program. When the computer program is executed by a processor, the computer program implements the following method:

[0038] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0039] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0040] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0041] The embodiments of the present invention provide a direct current boiler dry-to-wet state process control method and device. If it is determined that the direct current boiler dry-to-wet state conversion meets the pre-control conditions, the preset batch water flow rate is periodically obtained, and the water level of the water storage tank is monitored. If it is determined that the water level of the water storage tank is greater than the allowable water level for starting the boiler water pump, the supercooling water electric valve is opened; the boiler water circulation pump is started, and the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve are opened when the first preset time is reached to control and continuously monitor the water level of the water storage tank; if it is determined that the water level of the water storage tank is in a stable state and the boiler water circulation pump is operating normally, a prompt message indicating that the direct current boiler dry-to-wet state conversion has been completed is generated for manual confirmation that the direct current boiler dry-to-wet state conversion has been completed, which can ensure that the direct current boiler dry-to-wet state conversion process proceeds smoothly and reduces the time delay duration during the conversion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0043] Figure 1 This is a schematic diagram of a once-through boiler startup system provided by an embodiment of the present invention.

[0044] Figure 2 It is a flow chart of a method for controlling a dry-state to wet-state process of a direct-flow boiler provided in one embodiment of the present invention.

[0045] Figure 3 It is a structural diagram of a dry-state to wet-state process control device for a once-through boiler provided by one embodiment of the present invention.

[0046] Figure 4 A schematic diagram of the physical structure of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of this application can be combined with each other in any manner.

[0048] Explanation of related terms:

[0049] Wet state: The working medium water at the outlet of the water-cooled wall of the direct current boiler is in a water-containing state.

[0050] Dry state: The working medium water at the outlet of the water-cooled wall of the direct current boiler is in a superheated steam state. In practice, the superheat degree is generally required to be greater than 5°C.

[0051] Boiler water circulation pump: This pump is used to pump part or all of the liquid water at the water-cooled wall outlet of a once-through boiler in a wet state to the economizer inlet or water-cooled wall inlet.

[0052] like Figure 1 As shown, it is a schematic diagram of the direct current boiler starting system provided by an embodiment of the present invention. A direct current boiler refers to a boiler in which, under the pressure head of the feed water pump, the feed water undergoes three stages of heating, evaporation and superheating in the water-cooled wall at one time and is then converted into superheated steam with a certain pressure and temperature. No steam drum is required. This type of boiler is called a direct current boiler.

[0053] The once-through boiler starting system includes a feed water pump, a high-pressure heater, a main feed water electric valve, a feed water bypass regulating valve, a subcooled water electric valve, a boiler water circulation pump, a boiler water pump recirculation valve, a boiler water pump outlet flow meter, a boiler water pump outlet electric shut-off valve, a boiler water pump outlet regulating valve, a feed water flow meter, an economizer, a water-cooled wall, a boiler water pump warm-up valve, a starting system warm-up pipe valve, a steam-water separator, a water storage tank, a No. 1 361 regulating valve, a No. 1 361 regulating valve rear electric valve, a No. 2 361 regulating valve, a No. 2 361 regulating valve rear electric valve, an atmospheric expansion tank, a drain pump, and a drain flow meter, wherein:

[0054] The feed water pump is connected to the high-pressure heater, and the high-pressure heater is connected to the subcooled water electric valve and the main feed water electric valve respectively. The subcooled water electric valve is connected in parallel with a feed water bypass regulating valve. The subcooled water electric valve is connected to the boiler water circulation pump. The boiler water circulation pump is connected in parallel with a boiler water pump recirculation valve. The outlet end of the boiler water circulation pump is connected in sequence to the boiler water pump outlet flow meter, the boiler water pump outlet electric shut-off valve, and the boiler water pump outlet regulating valve. The outlet end of the boiler water pump outlet regulating valve is connected to the outlet end of the main feed water electric valve or the feed water bypass regulating valve and the feed water flow meter. The feed water flow meter is connected to the economizer. The economizer is connected to the water-cooled wall, the starting system warm-up pipe valve, and the boiler water pump warm-up valve respectively. The boiler water pump warm-up valve is connected to the outlet end of the boiler water circulation pump or the boiler water pump recirculation valve. The starting system warm-up pipe valve is connected to the first outlet end of the water storage tank.

[0055] The water-cooled wall is connected to the steam-water separator, the steam-water separator is connected to the inlet end of the water storage tank, the first outlet end of the water storage tank is connected in parallel with No. 361 regulating valve No. 1 and No. 361 regulating valve No. 2, the second outlet end of the water storage tank is connected to the inlet end of the boiler water circulation pump or the boiler water pump recirculation valve, No. 361 regulating valve No. 1 is connected to the electric valve after No. 361 regulating valve No. 1, the No. 361 regulating valve No. 2 is connected to the electric valve after No. 361 regulating valve No. 2, the electric valve after No. 361 regulating valve No. 1 and the electric valve after No. 361 regulating valve No. 2 are jointly connected to the inlet end of the atmospheric expansion tank, the outlet end of the atmospheric expansion tank is connected to two parallel drain pumps, and the outlet end of the drain pump is connected to the drain flowmeter.

[0056] The once-through boiler starting system is further described as follows:

[0057] The feed water pressurized by the feed water pump and heated by the high-pressure heater is mixed with the water flow at the outlet of the boiler water circulation pump, enters the economizer as feed water, and then enters the water-cooled wall. The total feed water flow is measured by the feed water flow meter.

[0058] The working medium heated by the economizer and the water wall enters the steam-water separator. In wet working conditions, the working medium entering the steam-water separator contains water, the liquid water flows to the water storage tank, and the steam flows to the superheater, etc. ( Figure 1 (Not shown) Liquid water entering the water storage tank can be pressurized by the boiler water circulation pump and returned to the economizer inlet, forming boiler water recirculation, increasing the inlet feedwater flow rate of the water-cooled wall. The heat of this boiler water also re-enters the water-cooled wall. The flow rate of this boiler water is measured by the boiler water pump outlet flowmeter.

[0059] The feed water entering the water storage tank can also enter the atmospheric expansion tank through the 361 valve, and then be discharged to the condenser through the drain pump ( Figure 1The heat of this liquid water is either carried away by the condenser or directly discharged, preventing heat recovery. The boiler water circulation pump has its own recirculation piping and a boiler water pump recirculation valve, a boiler water pump outlet flowmeter, an electric shutoff valve at the boiler water pump outlet, and a boiler water pump outlet regulating valve. The boiler water pump outlet regulating valve automatically controls the water level in the water storage tank.

[0060] When the boiler water circulating pump is shut down, the pump can be warmed up via valve 5 to ensure a suitable temperature for startup. The water inlet to the boiler water circulating pump requires a certain degree of subcooling to prevent impeller cavitation. Therefore, a stream of cold water from the feedwater line is mixed with saturated water from the water storage tank to reduce the temperature. This can be controlled by the opening of the cold water electric valve. The water storage tank also has an external discharge path. Water can be discharged to the atmospheric expansion tank via regulating valves 1 and 2, as well as the electric valves behind regulating valves 1 and 2. The automatic operation of valve 361 also controls the water level in the water storage tank.

[0061] When the water level in the atmospheric expansion tank is high, two drain pumps can be used to drain the liquid water to the condenser or wastewater disposal tank. During dry conditions, the start-up system warm-up valve can be opened to maintain the temperature of the pipeline from valve 361 to the water storage tank, keeping this section of the pipeline in standby mode at all times.

[0062] Figure 2 FIG. 1 is a flow chart of a method for controlling a dry-state to wet-state process of a once-through boiler according to an embodiment of the present invention. Figure 2 As shown, the embodiment of the present invention provides a dry-state to wet-state process control method for a once-through boiler, including:

[0063] Step S1: If it is determined that the dry-to-wet state conversion of the direct current boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level of the water storage tank is monitored. If it is determined that the water level of the water storage tank is greater than the allowable water level for starting the boiler water pump, the subcooling water electric valve is opened.

[0064] Step S2: Start the boiler water circulation pump, and open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve when the first preset time is reached to control and continuously monitor the water level in the water storage tank.

[0065] Step S3: If it is determined that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, a prompt message is generated indicating that the dry-state to wet-state conversion of the direct current boiler has been completed, so that manual confirmation of the completion of the dry-state to wet-state conversion of the direct current boiler is provided.

[0066] In step S1 above, if the device determines that the dry-to-wet transition of the once-through boiler meets the pre-control conditions, it periodically obtains the preset batch water flow rate and monitors the water level in the water storage tank. If the water level in the water storage tank exceeds the permissible level for the boiler water pump to start, it opens the subcooling water electric valve. The device can be a computer device that executes this method. The acquisition, storage, use, and processing of data in this technical solution comply with relevant regulations.

[0067] In step S2, the device starts the boiler water circulation pump and, after a first preset duration, opens the electric shutoff valve and regulating valve at the boiler water pump outlet to control and continuously monitor the water level in the water storage tank. The first preset duration can be set based on actual conditions and can be set to 10 seconds.

[0068] In the above step S3, if the device determines that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, it generates a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed, so as to provide manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0069] Determine whether the dry-to-wet transition of a once-through boiler meets the pre-control conditions, including:

[0070] The load is determined to be the minimum load in the dry state; the feed water flow in the dry state of the dry minimum load is greater than the sum of the native flow and the margin; the load is the power generation load of the unit. In the dry state, the power generation load of the unit can be reduced to the preset transition load. The preset transition load can be set independently according to actual conditions. Taking a 530MW unit as an example, the preset transition load can be selected as 150MW.

[0071] Bunsen flow rate: refers to the minimum safe flow rate to ensure good cooling of the water-cooled wall when the once-through boiler is running dry.

[0072] The margin can be set independently according to actual conditions and can be selected as 150t / h.

[0073] To start the boiler water circulation pump, you need to open the boiler water pump recirculation valve in advance, start the transition timer, open the electric valve after the regulating valve, close the starting system heating pipe valve, and close the boiler water pump heating pump valve.

[0074] The superheat at the separator outlet is controlled to a first preset temperature, the main steam pressure at the separator outlet is switched to constant pressure control, and the load is maintained stable for a second preset duration. The first preset temperature can be set based on actual conditions and can be set to 5°C. The second preset duration can be set based on actual conditions and can be set to 5 minutes. The main steam pressure at the separator outlet can be switched from sliding pressure control to constant pressure control.

[0075] The main differences between constant pressure control and sliding pressure control lie in their working principles, advantages and disadvantages, and applicable scenarios.

[0076] For working principle:

[0077] Constant pressure control: In constant pressure control mode, the boiler's coal feed automatically adjusts the main steam pressure to the set value. When the main steam pressure is lower than the set value, the boiler's coal feed automatically increases, increasing steam flow and raising pressure. When the main steam pressure is higher than the set value, the boiler's coal feed automatically decreases, reducing steam flow and lowering pressure.

[0078] Sliding pressure control: Under sliding pressure control mode, the boiler coal feed will automatically adjust the main steam pressure, but the main steam pressure changes with the unit load.

[0079] Regarding the pros and cons:

[0080] For the transition process given by the present invention, since the load remains unchanged, the pressure of the corresponding sliding pressure curve also remains unchanged. The effects of constant pressure control and sliding pressure control are both that the main steam pressure is a constant value. Therefore, directly selecting the constant pressure mode is a preferred option.

[0081] For applicable scenarios:

[0082] Constant pressure control: Applicable to situations where load changes are small, or where stable turbine output needs to be ensured.

[0083] Sliding pressure control: Applicable to situations with large load changes or when the turbine operation stability and efficiency need to be improved.

[0084] Release the automatic control of the superheat temperature at the outlet of the steam-water separator. Specifically, this may include switching the automatic control of the superheat temperature at the outlet of the steam-water separator to manual control, or semi-automatic control between manual control and automatic control.

[0085] The electric valve after opening the regulating valve comprises:

[0086] At the same time, open the electric valve behind the No. 1 361 regulating valve and the electric valve behind the No. 2 361 regulating valve.

[0087] The periodic acquisition of the preset batch water flow rate includes:

[0088] Determine the preset total feed water flow rate that needs to be increased when the direct current boiler switches from dry state to wet state, and determine the preset batch feed water flow rate for batch supply based on the preset total feed water flow rate; the current unit state can be used as the starting point of the switch, and then the flow rate at the boiler water pump outlet after the switch or the flow rate discharged by the 361 regulating valve can be used to give the preset total feed water flow rate ΔW that needs to be increased during the dry state to wet state process based on actual tests or theoretical methods.

[0089] Import the preset batch water flow rate one by one in batches according to the preset time period until all the preset total water flow rate is imported. The specific instructions are as follows:

[0090] Increase the water supply flow rate by (1 / N)×ΔW every 20 seconds, and complete the whole water supply process in N×20 seconds. Monitor the water level in the water storage tank. If it is determined that the water level in the water storage tank is greater than the allowable water level for starting the boiler water pump, open the subcooling water electric valve. The opening can be determined according to the debugging and can be selected as 40%. The purpose is to reduce the difference between the pump casing temperature and the inlet water temperature.

[0091] The once-through boiler dry-state to wet-state process control method further includes:

[0092] If it is determined that the boiler water circulation pump fails to start or does not exist, open the No. 1 361 regulating valve and the No. 2 361 regulating valve for automatic control to automatically inject water from the water storage tank into the atmospheric expansion tank;

[0093] Start a drain pump, and if the monitoring determines that the water level in the water storage tank is stable, the water level in the atmospheric expansion tank is stable, and the drain pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the once-through boiler has been completed is generated for manual confirmation. Figure 1 As shown, starting a drain pump can be Figure 1 If any one of the two drain pumps is in use, the other drain pump will be used as a backup.

[0094] The once-through boiler dry-state to wet-state process control method further includes:

[0095] Start a drain pump in the active / standby switching mode. Referring to the above description, if a drain pump fails, you can suspend the use of the drain pump and put the other drain pump into use.

[0096] The dry-to-wet-state process control method for a once-through boiler provided in an embodiment of the present invention is further described as follows:

[0097] 1. In dry state, reduce the generating load of the unit to the minimum load in dry state x1MW (for example: 530MW unit, x1 = 150MW). The feed water flow in dry state is greater than the Bensen flow + margin x2 (for example: x 2＝ 70t / h), the temperature deviation of adjacent water-cooled wall tubes can also be set to be less than 50℃, and the temperature deviation of tubes of the same type and plane (such as the outlet pipe of the front wall of the vertical water-cooled wall) can be less than 80℃. The specific values ​​are set independently according to the factory products of different boiler factories.

[0098] 2. Start the transition timing, open the electric valve behind the 361 regulating valve, close the start-up system warm-up pipe valve, close the boiler water pump warm-up pump valve, and open the boiler water pump recirculation valve.

[0099] 3. Control the superheat at the steam-water separator outlet to reduce to x3°C (for example: 5°C), switch the main steam pressure from sliding pressure control to constant pressure control, and maintain load stability for x4 minutes (for example: 5 minutes).

[0100] 4. Taking the current unit state as the starting point of the transition, based on the flow at the boiler water pump outlet or the flow discharged by the 361 valve after the transition, give the preset total feed water flow ΔW required to increase during the dry-state to wet-state transition process based on actual tests or theoretical methods.

[0101] 5. Release the automatic control of the superheat temperature at the outlet of the steam-water separator.

[0102] 6. Every x5 seconds, increase (1 / N)×ΔW, and complete in N×x5 seconds (for example: x5=20, N=5), and wait for the water level in the water storage tank to appear.

[0103] 7. If the water level in the water storage tank is greater than the water level allowed for the boiler water pump to start, open the subcooling water electric valve x6 (for example: the opening is 40%, which requires debugging, and its function is to reduce the difference between the pump casing temperature and the inlet water temperature).

[0104] 8. Start the boiler water circulation pump. After a preset time (e.g., 10 seconds), open the electric shutoff valve at the boiler water pump outlet. The boiler water pump outlet regulating valve automatically controls the water level in the water storage tank. If the boiler water pump fails to start, proceed to step 10. If the boiler water pump starts successfully, proceed to step 9.

[0105] 9. After confirming that the water level in the water storage tank is stable and the boiler water pump is operating normally, you can manually confirm the completion of the state change through the automatically generated prompt message indicating that the dry state change of the direct current boiler to the wet state has been completed (no further step will be taken).

[0106] 10.361 The regulating valve automatically controls the water level in the water storage tank, and the water storage tank discharges water into the atmospheric expansion tank.

[0107] 11. Put drain pump A into pre-selection and put drain pump B into standby, or put drain pump A into pre-selection and put drain pump B into standby.

[0108] 12. After confirming that the water level in the water storage tank is stable, the water level in the atmospheric expansion tank is stable, and the drain pump is operating normally, the completion of the dry-to-wet state transition of the direct current boiler can be manually confirmed by an automatically generated prompt message indicating that the transition has been completed.

[0109] The embodiment of the present invention provides a direct current boiler dry-to-wet state process control method. If it is determined that the direct current boiler dry-to-wet state conversion meets the pre-control conditions, the preset batch water flow rate is periodically obtained, and the water level of the water storage tank is monitored. If it is determined that the water level of the water storage tank is greater than the allowable water level for starting the boiler water pump, the supercooling water electric valve is opened; the boiler water circulation pump is started, and the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve are opened when the first preset time is reached to control and continuously monitor the water level of the water storage tank; if it is determined that the water level of the water storage tank is in a stable state and the boiler water circulation pump is operating normally, a prompt message indicating that the direct current boiler dry-to-wet state conversion has been completed is generated for manual confirmation that the direct current boiler dry-to-wet state conversion has been completed, which can ensure that the direct current boiler dry-to-wet state conversion process proceeds smoothly and reduces the time delay duration during the conversion process.

[0110] Furthermore, it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, including:

[0111] The load is determined to be the dry minimum load; the dry water flow rate of the dry minimum load is greater than the sum of the Bensen flow rate and the margin; the description of the above embodiment can be referred to and will not be repeated.

[0112] Start the transition timing, open the electric valve after the regulating valve, close the starting system heating pipe valve, close the boiler water pump heating pump valve, and open the boiler water pump recirculation valve; refer to the description of the above embodiment and no further details will be given.

[0113] Control the superheat degree at the steam-water separator outlet to the first preset temperature, switch the main steam pressure at the steam-water separator outlet to constant pressure control, and keep the load stable for the second preset time; refer to the description of the above embodiment and no further details will be given.

[0114] The automatic control of the superheat temperature at the outlet of the steam-water separator is released.

[0115] Furthermore, the electric valve after opening the regulating valve comprises:

[0116] At the same time, open the electric valve behind the No. 1 361 regulating valve and the electric valve behind the No. 2 361 regulating valve. Please refer to the description of the above embodiment and do not repeat them here.

[0117] Furthermore, the periodic acquisition of the preset batch water flow rate includes:

[0118] Determine the preset total feed water flow required to increase the dry state of the direct current boiler to the wet state, and determine the preset batch feed water flow for batch supply based on the preset total feed water flow; refer to the description of the above embodiment and no further details will be given.

[0119] The preset batch water flow rate is introduced in batches one by one according to the preset time period until the preset total water flow rate is fully introduced.

[0120] Furthermore, the once-through boiler dry-state to wet-state process control method further includes:

[0121] If it is determined that the boiler water circulation pump has failed to start or does not exist, the No. 1 361 regulating valve and the No. 2 361 regulating valve are opened for automatic control to realize automatic injection of water from the water storage tank into the atmospheric expansion tank; please refer to the description of the above embodiment and will not repeat it here.

[0122] A drain pump is started. If monitoring determines that the water level in the water storage tank is stable, the water level in the atmospheric expansion tank is stable, and the drain pump is operating normally, a prompt message is generated indicating that the dry-to-wet transition of the once-through boiler has been completed, allowing manual confirmation of the completion of the dry-to-wet transition. This is explained in the above embodiment and will not be repeated here.

[0123] Furthermore, the once-through boiler dry-state to wet-state process control method further includes:

[0124] The method of starting a drain pump by switching between the active and standby modes can be referred to the description of the above embodiment and will not be repeated here.

[0125] Figure 3 FIG. 1 is a schematic diagram of a dry-to-wet-state process control device for a once-through boiler according to an embodiment of the present invention. Figure 3 As shown, the dry-state to wet-state process control device of a once-through boiler provided in an embodiment of the present invention includes a first control unit 301, a second control unit 302, and a third control unit 303, wherein:

[0126] The first control unit 301 is used to periodically obtain the preset batch water flow rate and monitor the water level in the water storage tank if it is determined that the dry-to-wet state conversion of the direct current boiler meets the pre-control conditions. If it is determined that the water level in the water storage tank is greater than the allowable water level for starting the boiler water pump, the subcooling water electric valve is opened; the second control unit 302 is used to start the boiler water circulation pump, and open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve when the first preset time is reached to control and continuously monitor the water level in the water storage tank; the third control unit 303 is used to generate a prompt message indicating that the dry-to-wet state conversion of the direct current boiler has been completed if it is determined that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, so as to provide manual confirmation that the dry-to-wet state conversion of the direct current boiler is completed.

[0127] Specifically, the first control unit 301 in the device is used to periodically obtain the preset batch water flow rate and monitor the water level in the water storage tank if it is determined that the dry-to-wet state conversion of the direct current boiler meets the pre-control conditions. If it is determined that the water level in the water storage tank is greater than the allowable water level for starting the boiler water pump, the subcooling water electric valve is opened; the second control unit 302 is used to start the boiler water circulation pump, and open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve when the first preset time is reached to control and continuously monitor the water level in the water storage tank; the third control unit 303 is used to generate a prompt message indicating that the dry-to-wet state conversion of the direct current boiler has been completed if it is determined that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, so as to provide manual confirmation that the dry-to-wet state conversion of the direct current boiler is completed.

[0128] The dry-to-wet state process control device provided by the embodiment of the present invention periodically obtains the preset batch water flow rate and monitors the water level of the water storage tank if it is determined that the dry-to-wet state process of the direct current boiler meets the pre-control conditions. If it is determined that the water level of the water storage tank is greater than the allowable water level for starting the boiler water pump, the supercooling water electric valve is opened; the boiler water circulation pump is started, and the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve are opened when the first preset time is reached to control and continuously monitor the water level of the water storage tank; if it is determined that the water level of the water storage tank is in a stable state and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-to-wet state process of the direct current boiler has been completed is generated for manual confirmation that the dry-to-wet state process of the direct current boiler is completed, which can ensure that the dry-to-wet state process of the direct current boiler proceeds smoothly and reduce the time delay duration during the process.

[0129] Furthermore, the once-through boiler dry-state to wet-state process control device is specifically used for:

[0130] Determining the load to be a dry minimum load; the water flow rate in the dry state of the dry minimum load is greater than the sum of the Bunsen flow rate and the margin;

[0131] Start the transition timer, open the electric valve behind the regulating valve, close the start-up system warm-up valve, close the boiler water pump warm-up valve, and open the boiler water pump recirculation valve;

[0132] Controlling the superheat degree at the outlet of the steam-water separator to a first preset temperature, switching the main steam pressure at the outlet of the steam-water separator to constant pressure control, and maintaining the load stable for a second preset time;

[0133] Release the automatic control of the superheat temperature at the steam-water separator outlet.

[0134] Furthermore, the once-through boiler dry-state to wet-state process control device is specifically used for:

[0135] At the same time, open the electric valve behind the No. 1 361 regulating valve and the electric valve behind the No. 2 361 regulating valve.

[0136] Furthermore, the once-through boiler dry-state to wet-state process control device is specifically used for:

[0137] Determine the preset total feed water flow rate required to increase the dry state of the once-through boiler to the wet state, and determine the preset batch feed water flow rates for batch supply based on the preset total feed water flow rate;

[0138] The preset batch water supply flow is imported one by one in batches according to the preset time period until the preset total water supply flow is fully imported.

[0139] Furthermore, the once-through boiler dry-state to wet-state process control device is also used for:

[0140] If it is determined that the boiler water circulation pump fails to start or does not exist, open the No. 1 361 regulating valve and the No. 2 361 regulating valve for automatic control to automatically inject water from the water storage tank into the atmospheric expansion tank;

[0141] Start a drain pump, and if monitoring determines that the water level in the water storage tank is stable, the water level in the atmospheric expansion tank is stable, and the drain pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct-current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct-current boiler has been completed.

[0142] Furthermore, the once-through boiler dry-state to wet-state process control device is also used for:

[0143] Start a drain pump through the active / standby switchover mode.

[0144] The embodiment of the present invention provides an embodiment of a dry-to-wet state process control device for a direct current boiler, which can be specifically used to execute the processing flow of the above-mentioned method embodiments. Its functions are not described in detail here, and reference can be made to the detailed description of the above-mentioned method embodiments.

[0145] Figure 4 A schematic diagram of the physical structure of a computer device provided in an embodiment of the present invention is shown in FIG. Figure 4 As shown, the computer device includes: a memory 401, a processor 402, and a computer program stored in the memory 401 and executable on the processor 402. When the processor 402 executes the computer program, the following method is implemented:

[0146] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0147] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0148] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0149] This embodiment discloses a computer program product, which includes a computer program. When the computer program is executed by a processor, the following method is implemented:

[0150] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0151] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0152] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0153] This embodiment provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the following method is implemented:

[0154] If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened;

[0155] Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank;

[0156] If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

[0157] Compared with the technical solutions in the prior art, the embodiments of the present invention provide a method for controlling the process of direct current boilers from dry to wet states. If it is determined that the direct current boiler from dry to wet states meets the pre-control conditions, the preset batch water flow rate is periodically obtained, and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for starting the boiler water pump, the supercooling water electric valve is opened; the boiler water circulation pump is started, and the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve are opened when the first preset time is reached to control and continuously monitor the water level in the water storage tank. If it is determined that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, a prompt message indicating that the direct current boiler from dry to wet states has been completed is generated for manual confirmation that the direct current boiler from dry to wet states has been completed, which can ensure that the direct current boiler from dry to wet states proceeds smoothly and reduce the time delay during the transition process.

[0158] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0159] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0160] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0161] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0162] Throughout this specification, reference to terms such as "one embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0163] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A control method for a dry-to-wet state transition process of a once-through boiler, characterized in that: include: If it is determined that the dry-to-wet state transition of the once-through boiler meets the pre-control conditions, the preset batch water flow rate is periodically obtained and the water level in the water storage tank is monitored. If it is determined that the water level in the water storage tank is greater than the allowable water level for the boiler water pump to start, the subcooling water electric valve is opened; Start the boiler water circulation pump, and when the first preset time is reached, open the boiler water pump outlet electric shut-off valve and the boiler water pump outlet regulating valve to control and continuously monitor the water level in the water storage tank; If it is determined that the water level in the water storage tank is stable and the boiler water circulation pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

2. The dry-to-wet state process control method for a once-through boiler according to claim 1 is characterized in that: Determine whether the dry-to-wet transition of a once-through boiler meets the pre-control conditions, including: Determining the load to be a dry minimum load; the water flow rate in the dry state of the dry minimum load is greater than the sum of the Bunsen flow rate and the margin; Start the transition timer, open the electric valve behind the regulating valve, close the start-up system warm-up valve, close the boiler water pump warm-up valve, and open the boiler water pump recirculation valve; Controlling the superheat degree at the outlet of the steam-water separator to a first preset temperature, switching the main steam pressure at the outlet of the steam-water separator to constant pressure control, and maintaining the load stable for a second preset time; Release the automatic control of the superheat temperature at the steam-water separator outlet.

3. The dry-to-wet state process control method for a once-through boiler according to claim 2, characterized in that: The electric valve after opening the regulating valve comprises: At the same time, open the electric valve behind the No. 1 361 regulating valve and the electric valve behind the No. 2 361 regulating valve.

4. The dry-to-wet state process control method for a once-through boiler according to claim 1, characterized in that: The periodic acquisition of the preset batch water flow rate includes: Determine the preset total feed water flow rate required to increase the dry state of the once-through boiler to the wet state, and determine the preset batch feed water flow rates for batch supply based on the preset total feed water flow rate; The preset batch water supply flow is imported one by one in batches according to the preset time period until the preset total water supply flow is fully imported.

5. The dry-state to wet-state process control method for a once-through boiler according to any one of claims 1 to 4, characterized in that: The once-through boiler dry-state to wet-state process control method further includes: If it is determined that the boiler water circulation pump fails to start or does not exist, open the No. 1 361 regulating valve and the No. 2 361 regulating valve for automatic control to automatically inject water from the water storage tank into the atmospheric expansion tank; Start a drain pump, and if monitoring determines that the water level in the water storage tank is stable, the water level in the atmospheric expansion tank is stable, and the drain pump is operating normally, a prompt message indicating that the dry-state to wet-state conversion of the direct-current boiler has been completed is generated for manual confirmation that the dry-state to wet-state conversion of the direct-current boiler has been completed.

6. The dry-to-wet state process control method for a once-through boiler according to claim 5, characterized in that: The once-through boiler dry-state to wet-state process control method further includes: Start a drain pump through the active / standby switchover mode.

7. A dry-to-wet process control device for a once-through boiler, characterized in that: include: The first control unit is configured to periodically obtain a preset batch water flow rate and monitor the water level in the water storage tank if it is determined that the dry-state to wet-state transition of the once-through boiler satisfies the pre-control condition, and to open the subcooling water electric valve if it is determined that the water level in the water storage tank is greater than the boiler water pump start-up allowable water level; The second control unit is used to start the boiler water circulation pump and open the electric shut-off valve and the boiler water pump outlet regulating valve at the first preset time to control and continuously monitor the water level of the water storage tank; The third control unit is used to generate a prompt message indicating that the dry-state to wet-state conversion of the direct current boiler has been completed if it is determined that the water level in the water storage tank is in a stable state and the boiler water circulation pump is operating normally, so as to provide manual confirmation that the dry-state to wet-state conversion of the direct current boiler has been completed.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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