Methods, devices, equipment, storage media, and program products for starting and stopping coal-fired power units based on power microcomputers.

Abstract

This application relates to a method, apparatus, equipment, storage medium, and program product for starting and stopping a coal-fired power unit based on a power generator. The method includes: when the main turbine is shut down, controlling the boiler to continue operating by using steam generated by the boiler to drive the power generator; using the power generator to drive the feedwater pump to supply water to the boiler to maintain water circulation; using the extraction or exhaust steam from the power generator to heat the regenerative equipment in the feedwater pump to maintain the feedwater temperature; and upon receiving a main turbine start-up command and when the steam parameters generated by the boiler meet the preset main turbine start-up requirements, controlling the main turbine to start up and enter the grid-connected power generation process. This solution enables rapid start-up and shutdown of the unit, reduces start-up energy consumption, and enhances operational flexibility.

Description

Technical Field

[0001] This application relates to the field of thermal power unit technology, and in particular to a method, apparatus, computer equipment, computer-readable storage medium and computer program product for starting and stopping coal-fired power units based on a power microcomputer. Background Technology

[0002] As the proportion of renewable energy generation in the power grid continues to increase, the power system is placing higher demands on the peak-shaving capacity and response speed of thermal power units. As the mainstay of power supply, coal-fired power units frequently participate in deep peak shaving and rapid start-up and shutdown, which has become the norm.

[0003] Currently, existing coal-fired power units typically include a boiler, turbine, generator, and auxiliary systems. When starting or stopping a coal-fired power unit, pre-startup preparations are usually carried out first. Then, the water pump and turbine are started to run to fill the boiler with water, followed by boiler ignition. At this time, the high and low pressure bypasses are opened, and the steam generated by the boiler enters the condenser through the high and low pressure bypass desuperheating and pressure reduction. Subsequently, the high and low pressure bypass valves are gradually closed, and the steam generated by the boiler heats up and pressurizes until it meets the steam pressure and temperature requirements for starting the main unit.

[0004] When a coal-fired power unit is shut down, the boiler is also shut down and cooled, which means that restarting requires a lengthy process of re-ignition, heating up, and pressurizing from a cold (or warm) state. This process is not only time-consuming (usually several hours), resulting in a slow response to grid dispatch commands, but also consumes a large amount of fuel oil, plant power, and steam from adjacent units during startup and shutdown, causing significant energy waste. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, apparatus, computer equipment, computer-readable storage medium, and computer program product for starting and stopping coal-fired power units based on a small power unit that can effectively reduce energy consumption, in response to the above-mentioned technical problems.

[0006] In a first aspect, this application provides a start-up and shutdown method for a coal-fired power unit based on a power generator, wherein the coal-fired power unit includes a boiler, a main steam turbine, a power generator, a motor, and a feedwater pump, wherein the power generator is coaxially connected to the motor and the feedwater pump, and the method includes:

[0007] When the main steam turbine is shut down, the boiler is controlled to continue operating, and the steam generated by the boiler drives the power generator.

[0008] The power generator drives the water pump to supply water to the boiler in order to maintain the water circulation of the boiler;

[0009] The steam extracted or exhausted by the power generator is used to heat the regenerator in the water pump to maintain the water temperature.

[0010] Upon receiving the host start command and if the steam parameters generated by the boiler meet the preset host start-up requirements, the main steam turbine is controlled to start up and enter the grid-connected power generation process.

[0011] In one embodiment, the operation of the power generator driven by the steam generated by the boiler includes:

[0012] The main steam generated by the boiler is divided into two streams after being de-heated and de-pressurized via a bypass.

[0013] One stream of steam enters the reheater of the boiler, while the other stream of steam passes through the turbine inlet valve and enters the power generator to drive its rotation.

[0014] In one embodiment, the method further includes:

[0015] When the main steam turbine is shut down, the steam output from the reheater is controlled to be output through the heating valve;

[0016] The driving steam source for the power generator comes from the steam pipeline corresponding to the exhaust steam of the high-pressure cylinder of the main steam turbine or the steam pipeline after the bypass.

[0017] In one embodiment, the step of driving the feedwater pump to supply water to the boiler via the power generator includes:

[0018] Monitor the output power of the power generator and the load requirements of the water pump;

[0019] If the output power of the power generator is insufficient to drive the water pump, the motor is controlled to switch to electric motor mode to assist in driving the water pump.

[0020] When the output power of the power generator exceeds the load requirement of the water pump, the motor is controlled to switch to motor mode to generate electricity using the excess energy.

[0021] In one embodiment, the coal-fired power unit further includes a high-pressure heater, a deaerator, and a low-pressure heater; the heating of the regenerator in the feedwater pump by extracting or venting steam from the power generator includes:

[0022] The extracted steam from the power generator is introduced into the high-pressure heater and deaerator;

[0023] The exhaust steam from the aforementioned small power generator is introduced into the low-pressure heater;

[0024] The water supply temperature of the feed water pump is maintained within a preset temperature range through the coordinated operation of the high-pressure heater, the deaerator, and the low-pressure heater.

[0025] In one embodiment, controlling the main steam turbine to start includes:

[0026] During the main steam turbine's start-up and grid connection process, the high-pressure exhaust steam temperature is monitored;

[0027] By adjusting the steam flow rate entering the power generator, the reheat steam pressure is maintained at a preset low pressure value to control the high-temperature exhaust steam temperature from exceeding the limit.

[0028] When the reheat steam pressure decreases, causing insufficient driving force for the power generator, the motor is controlled to switch to electric motor mode.

[0029] Secondly, this application also provides a start-stop device for a coal-fired power unit based on a power generator, deployed in a coal-fired power unit, the coal-fired power unit including a boiler, a main steam turbine, a power generator, a motor, and a feedwater pump, wherein the power generator is coaxially connected to the motor and the feedwater pump, and the device includes:

[0030] The first drive module is used to control the boiler to continue operating when the main steam turbine is in a shutdown state, and to drive the power generator to run by the steam generated by the boiler.

[0031] The second drive module is used to drive the feedwater pump to supply water to the boiler through the power motor, so as to maintain the water circulation of the boiler;

[0032] The heating control module is used to heat the regenerator in the feedwater pump by extracting or venting steam from the power generator to maintain the feedwater temperature.

[0033] The start-up control module is used to control the main steam turbine to start up and enter the grid-connected power generation process when it receives the start-up command of the main unit and the steam parameters generated by the boiler meet the preset start-up requirements of the main unit.

[0034] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in any of the above embodiments of the coal-fired power unit start-up and shutdown method based on a power microcomputer.

[0035] Fourthly, this application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps in any of the above embodiments of the coal-fired power unit start-up and shutdown method based on a power microcomputer.

[0036] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps in any of the above embodiments of the coal-fired power unit start-up and shutdown method based on a power microcomputer.

[0037] The aforementioned start-up and shutdown methods, devices, computer equipment, storage media, and computer program products for coal-fired power units based on a power generator utilize boiler waste steam to drive the power generator to maintain feedwater pump circulation and regenerative heating during the main turbine shutdown period, keeping the boiler in hot standby mode. This effectively reduces the lengthy boiler raising and pipe warming process in traditional cold start-ups, thus significantly shortening the unit start-up time. Simultaneously, the power generator enables self-sufficiency in plant power, reducing dependence on external power sources and lowering start-up energy consumption. Furthermore, maintaining stable boiler water circulation and feedwater temperature not only improves the safety and reliability of the start-up process but also provides technical support for the unit's rapid response to grid peak-shaving demands, significantly enhancing the operational flexibility and regulation capabilities of the coal-fired power unit. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart illustrating a method for starting and stopping a coal-fired power unit based on a power generator in one embodiment.

[0040] Figure 2 This is a system architecture diagram of a coal-fired power unit operating normally based on a power microcomputer in one embodiment.

[0041] Figure 3 This is a flowchart illustrating the step of driving a feedwater pump to supply water to a boiler in one embodiment.

[0042] Figure 4 This is a flowchart illustrating the process of controlling the main steam turbine to start up in another embodiment;

[0043] Figure 5 This is a system architecture diagram of a coal-fired power unit based on a power microcomputer during the rapid start-up and shutdown operation phase in one embodiment.

[0044] Figure 6 This is a structural block diagram of a coal-fired power unit start-stop device based on a power microcomputer in one embodiment;

[0045] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0048] The current start-up and shutdown process of thermal power units faces multiple challenges in balancing efficiency, safety, and economy. On the one hand, traditional start-up and shutdown procedures are time-consuming and energy-intensive, and the unit's regulation capabilities are limited during start-up and shutdown, making it difficult to quickly respond to grid demands and affecting the stability of the entire power system. On the other hand, achieving rapid start-up and shutdown is key to improving unit flexibility, and its core lies in rapid temperature and pressure rise control technology. This technology aims to accelerate the rise in temperature and pressure of the boiler steam-water system by dynamically optimizing parameters such as fuel, feedwater, and air volume, while ensuring equipment safety, thereby shortening the time from startup to grid connection.

[0049] However, there is an inherent contradiction between "speed" and "safety." The core risk of rapid heating and pressurization lies in thermal stress. Thick-walled metal components of the unit, such as the steam drum and turbine cylinder, undergo intense "heating-cooling" cycles during start-up and shutdown. If the temperature changes too quickly, enormous thermal stress will be generated. For example, to prevent cracks or permanent deformation, the temperature difference between the upper and lower walls of the steam drum must typically be controlled within 50°C, and the temperature difference in the turbine cylinder must be controlled within 40°C. Frequent start-ups and shutdowns can lead to the accumulation of metal fatigue. If the number of start-ups and shutdowns exceeds 24 hours (e.g., 3 or more), it may exceed the fatigue limit of the material, causing serious safety risks.

[0050] Furthermore, start-up and shutdown processes are subject to both time and economic constraints. A subcritical unit typically requires 4 to 6 hours to go from a cold start to full load, and even a hot or warm start requires 2 to 4 hours, while the shutdown process itself takes 1 to 2 hours. This means that multiple start-ups and shutdowns within 24 hours are already nearing their time limit; forcibly increasing the number of starts and shutdowns would result in the next cycle starting before the previous one is completed, significantly increasing the risk. At the same time, each start-up and shutdown process itself consumes a lot of energy, and frequent operations will significantly increase power generation costs, weakening its economic viability as a peak-shaving method. Therefore, rapid start-up and shutdown of thermal power units must strike a delicate balance between equipment safety, time windows, and economic costs.

[0051] like Figure 1 As shown, in an exemplary embodiment, a start-up and shutdown method for a coal-fired power unit based on a power generator is provided. The coal-fired power unit includes a boiler, a main steam turbine, a power generator, a motor, and a feedwater pump, wherein the power generator is coaxially connected to the motor and the feedwater pump. Taking the application of this method to the controller of the coal-fired power unit as an example, the method includes the following steps 100 to 400. Wherein:

[0052] Step 100: When the main steam turbine is shut down, control the boiler to continue operating and drive the power generator through the steam generated by the boiler.

[0053] In this embodiment, the auxiliary power unit is a small steam turbine driven by steam. Its main function is to drive the feedwater pump and it can also generate electricity, serving as an auxiliary power unit for the main steam turbine. In this embodiment, the normal operation system diagram of the coal-fired power unit is as follows: Figure 2 As shown.

[0054] In practical applications, the controller of a coal-fired power unit monitors the main steam turbine's speed, power output, and operating status signals in real time using sensors. When the main steam turbine is shut down, the boiler and power generator continue operating. The controller confirms that the main steam turbine is shut down and has no load output. Subsequently, the controller continuously collects key parameters such as the boiler's furnace temperature, steam pressure, and steam flow rate to determine if the boiler still has a stable steam production capacity. If the boiler is confirmed to have a stable steam production capacity, based on the above data, the controller maintains the boiler's combustion system operation, adjusting the fuel supply and airflow ratio to ensure that steam parameters remain stable within the set range. Simultaneously, the controller opens the steam regulating valve leading to the power generator, guiding the steam generated by the boiler into the power generator to drive its rotation and perform work. During this process, the controller can also dynamically adjust the opening of the steam inlet valve based on the power generator's speed feedback signal, ensuring that the power generator operates stably within its rated or target speed range, achieving efficient energy utilization.

[0055] Step 200: The power motor drives the feedwater pump to supply water to the boiler in order to maintain the water circulation of the boiler.

[0056] The feedwater pump is a key auxiliary equipment used to pressurize feedwater and send it into the boiler, ensuring that the boiler receives a continuous water supply under high pressure.

[0057] In practical applications, the controller can collect real-time signals of the feedwater pump's inlet and outlet pressures, flow rate, and the motor's rotation speed. Besides maintaining boiler operation and using the steam generated by the boiler to drive the motor, the controller also uses the motor to drive the feedwater pump to supply water to the boiler. By comparing the actual feedwater flow rate with the setpoint corresponding to the boiler load demand, the controller calculates the deviation and outputs adjustment commands to control the opening of the motor's steam inlet regulating valve, thereby changing its output power and speed, and ultimately adjusting the feedwater pump's speed and output to ensure the feedwater flow rate remains stable within the target range. When a drop in boiler water level is detected, the controller automatically increases the steam intake of the motor, increases the feedwater pump speed, and increases the water supply; conversely, it decreases the steam intake and reduces the water supply.

[0058] Step 300: The regenerator in the feedwater pump is heated by the extraction or exhaust of steam from the power generator to maintain the feedwater temperature.

[0059] Regenerative equipment refers to heat exchange devices that use steam extracted or exhausted from a steam turbine to heat feedwater, such as low-pressure heaters and deaerators, to increase feedwater temperature and reduce boiler heat load.

[0060] After the controller drives the feedwater pump to supply water to the boiler via a power amplifier, it can collect the feedwater inlet temperature, outlet temperature, steam pressure, and flow rate signals of the regenerative heating system to determine whether the current feedwater temperature is lower than the set target value. If the temperature is insufficient, the controller initiates the regenerative heating process, controlling the opening of the power amplifier's extraction or exhaust valve to introduce steam after it has done work into the regenerative heating system. The steam exchanges heat with the feedwater in the heater, releasing latent heat before condensing and being discharged, thus heating the feedwater to the target temperature. The controller controls the amount of steam entering the regenerative heating system by adjusting the steam valve opening, ensuring the feedwater temperature remains stable within the set range. Simultaneously, the controller monitors the heater water level to reduce the risk of overfilling or dry burning.

[0061] Step 400: Upon receiving the main unit start command and if the steam parameters generated by the boiler meet the preset main unit start-up requirements, control the main steam turbine to start up and enter the grid-connected power generation process.

[0062] Main turbine startup refers to the process by which the main steam turbine starts from a standstill, drives the rotor to rotate by introducing steam, and gradually increases its speed to the rated speed. This is a crucial step in starting the unit. Grid-connected power generation refers to the entire process by which the main steam turbine, after reaching synchronous speed, connects to the power grid synchronously and begins to output electrical energy.

[0063] In practical applications, the controller can receive start-up commands from the power grid dispatch system in real time and simultaneously collect parameters such as steam pressure, temperature, and flow rate at the boiler outlet to determine whether preset start-up conditions are met, such as steam pressure ≥ a set threshold, temperature fluctuation within ±5℃, and sufficient superheat. If the steam parameters generated by the boiler meet the preset start-up requirements, the controller sends opening commands to the main steam valve and regulating valve of the main turbine, controlling steam to enter the turbine and drive the rotor to start running. During the start-up process, the controller controls the valve opening according to a predetermined curve based on feedback signals from the speed sensor, achieving smooth speed increase and avoiding thermal shock and mechanical vibration. When the speed approaches synchronous speed, the controller activates the synchronizing device to adjust the generator frequency and phase to match the grid. At the moment of phase overlap, a closing command is issued to complete grid connection. Subsequently, the load is gradually increased, entering the normal power generation process.

[0064] The aforementioned start-up and shutdown method for coal-fired power units based on a power generator utilizes residual steam from the boiler to drive a power generator to maintain feedwater pump circulation and regenerative heating during the main turbine shutdown period, keeping the boiler in a hot standby state. This effectively reduces the lengthy boiler raising and pipe warming process in traditional cold start-ups, thus significantly shortening the unit start-up time. Simultaneously, the power generator enables self-sufficiency in plant power consumption, reducing dependence on external power sources and lowering start-up energy consumption. Furthermore, maintaining stable boiler water circulation and feedwater temperature not only enhances the safety and reliability of the start-up process but also provides technical support for the unit's rapid response to grid peak-shaving demands, significantly enhancing the operational flexibility and regulation capabilities of the coal-fired power unit.

[0065] In some exemplary embodiments, the operation of the power generator is driven by the steam generated by the boiler, including: dividing the main steam generated by the boiler into two paths after bypassing the temperature and pressure reduction; one path of steam enters the boiler's reheater, and the other path of steam enters the power generator through the turbine inlet valve to drive the power generator to rotate.

[0066] In practical applications, when the main steam turbine is shut down but the power generator is running, the controller activates the high-pressure bypass control logic, issuing a command to adjust the opening of the high-pressure bypass valve to introduce main steam into the bypass system. Simultaneously, the controller calculates the required water injection volume based on the allowable steam temperature limit at the reheater inlet, controlling the desuperheating water regulating valve to achieve online desuperheating and pressure reduction of the steam, ensuring that one stream of steam meets the reheater's safety heating requirements before entering the reheater. At the same time, the controller opens the turbine inlet valve leading to the power generator, introducing another stream of main steam into the power generator to perform work. Throughout this process, the controller continuously collects real-time data such as the power generator's speed, inlet steam pressure, and exhaust steam pressure, constructing a closed-loop feedback control system. If the speed is lower than the target value, the controller increases the turbine inlet valve opening to increase the steam intake; if the inlet steam pressure is too high, the valve is appropriately closed to prevent overpressure. Simultaneously, the system monitors the desuperheating water pressure and flow rate to ensure stable desuperheating effect and prevent wet steam from entering the reheater or power generator, causing water hammer or blade damage. The controller also determines whether the main steam flow of the boiler is sufficient and rationally allocates the steam ratio entering the reheater and the power generator to ensure stable boiler operation and efficient utilization of thermal energy.

[0067] In this embodiment, by setting up a high-pressure bypass and combining it with desuperheating and pressure reduction technology, the main steam generated by the boiler is rationally distributed to the reheater and the power generator. This allows the reheater to maintain hot operation and drive the power generator even when the main turbine is shut down. This effectively utilizes the boiler's waste heat, reduces energy waste, and improves the system's thermal efficiency and start-up flexibility.

[0068] In some exemplary embodiments, the method further includes controlling the output steam from the reheater to be output through a heating valve when the main turbine is shut down.

[0069] The power generator's driving steam source comes from the steam pipeline corresponding to the exhaust steam of the high-pressure cylinder of the main steam turbine or the steam pipeline after the bypass.

[0070] The steam pipeline corresponding to the high-pressure cylinder exhaust refers to the intermediate connecting pipeline that discharges the remaining steam energy after the high-pressure cylinder of the main steam turbine has completed part of the work and transports it to the reheater for temperature increase. Its steam parameters are between those of the main steam and the reheat steam.

[0071] In practical applications, when the main steam turbine is shut down, the controller first confirms that the main unit is not rotating and the steam inlet valves are fully closed, then initiates the thermal energy cascade utilization control logic. The controller collects the steam pressure, temperature, and flow signals at the reheater outlet to determine if they meet the requirements for external heating or process steam. If they do, the controller outputs a command to open the heating valves and adjusts the valve opening based on the flow demand signal from the heat user to stabilize the output steam, achieving an energy-efficient utilization mode of continuous heating during shutdown. Simultaneously, the controller enters the steam source selection and switching process for the power generator, reading the pressure and temperature sensor data in real time from the high-pressure cylinder exhaust pipeline and the steam pipeline after the high-pressure bypass, and combining this with the power generator's startup characteristic curve to determine which steam parameters are more suitable as the driving steam source. When the high-pressure cylinder exhaust parameters are stable and available, the controller prioritizes this path, issuing a command to open the corresponding pipeline's isolation valve and regulating valve to guide steam into the power generator; if the parameters of this path are insufficient or unavailable, it switches to the steam pipeline after the high-pressure bypass as a backup steam source. Throughout the process, the controller continuously monitors the speed, vibration, and steam inlet pressure of the auxiliary power unit, constructing a multivariable feedback control loop to ensure smooth and shock-free operation when switching between different steam sources. Furthermore, the system dynamically coordinates the distribution ratio between the heating steam supply and the steam consumption of the auxiliary power unit based on the boiler load and steam output, preventing boiler overpressure or insufficient steam, and achieving coordinated and optimized control of combined heat and power (CHP) and auxiliary equipment drive.

[0072] In this embodiment, by using reheater output steam to provide external heat during the main turbine shutdown period, and flexibly selecting the steam pipeline after high-pressure cylinder exhaust or high-pressure bypass as the driving steam source for the auxiliary generator, the cascade utilization of thermal energy and independent steam supply for auxiliary machine drive are realized, thereby improving the energy utilization efficiency and operational flexibility of the unit during start-up and shutdown.

[0073] like Figure 3 As shown, in some exemplary embodiments, step 200 includes:

[0074] Step 210: Monitor the output power of the power generator and the load requirements of the water pump.

[0075] Step 220: If the output power of the small power unit is insufficient to drive the water pump, control the motor to switch to electric motor mode to assist in driving the water pump.

[0076] Step 230: When the output power of the small power generator is greater than the load demand of the water pump, control the motor to switch to motor mode and use the excess energy to generate electricity.

[0077] In this embodiment, the motor can be a dual-purpose generator / electric motor.

[0078] In practical applications, the controller can first acquire the current output power signal of the power generator in real time through a speed-power sensor installed at the output shaft end of the power generator, and simultaneously obtain the load demand data required for the operation of the feedwater pump. This data is calculated based on the boiler drum water level, feedwater flow setpoint, and pump inlet pressure. Subsequently, the controller compares the actual output power of the power generator with the real-time load demand of the feedwater pump to determine the power matching relationship between the two.

[0079] If the output power of the power generator is insufficient to drive the water pump (i.e., the power difference is negative and exceeds a set threshold), the controller immediately generates a drive command to switch the motor coaxially connected to the water pump or connected via a coupling device to motor mode. In this mode, the controller adjusts the frequency converter to supply power to the motor, generating auxiliary drive torque to drive the water pump together with the power generator, ensuring stable operation of the water supply system. Conversely, when the output power of the power generator exceeds the load demand of the water pump, the controller determines that the excess energy can be used for power generation and immediately issues a mode switching command to switch the motor control to motor mode. At this time, the excess mechanical energy output by the power generator drives the motor to rotate through the transmission system, and the controller adjusts the excitation system and grid connection device to transmit the generated electrical energy to the plant power system or the power grid. Throughout the process, the controller continuously monitors the motor's current, voltage, speed, and the operating status of the power generator, dynamically adjusting control parameters to ensure smooth and shock-free switching between the two modes and to reduce the occurrence of reverse power or overload phenomena. In other embodiments, the system also includes priority logic to prioritize drive reliability and automatically suppress power generation mode when the boiler water level is abnormal or the water demand changes abruptly, thereby ensuring unit safety.

[0080] In this embodiment, by real-time monitoring of the power matching relationship between the power generator and the feedwater pump, and by controlling the motor to flexibly switch between motor mode and motor mode, stable drive of the feedwater system and recovery of excess energy for power generation are achieved during the shutdown of the main steam turbine, thereby improving the energy utilization efficiency and operating economy of the auxiliary system.

[0081] In some exemplary embodiments, the coal-fired power unit further includes a high-pressure heater, a deaerator, and a low-pressure heater; heating the regenerator in the feedwater pump by extracting or venting steam from the power generator includes:

[0082] Steam extracted from the power generator is introduced into the high-pressure heater and deaerator, while exhaust steam from the power generator is introduced into the low-pressure heater. Through the coordinated operation of the high-pressure heater, deaerator, and low-pressure heater, the feedwater temperature of the feedwater pump is maintained within the preset temperature range.

[0083] During the operation of the coal-fired power unit, the controller first receives operating status signals from the power generator, including extraction steam pressure, temperature, and exhaust steam parameters. Combined with real-time data such as the current water levels of the high-pressure heater, deaerator, and low-pressure heater, and the inlet and outlet temperatures of the feedwater, the controller performs coordinated control of the regenerative system. Once the power generator is running stably, the controller automatically opens the corresponding extraction steam pipeline regulating valve based on whether its extraction steam parameters meet the heating requirements of the high-pressure heater and deaerator. This introduces medium-temperature, medium-pressure steam into the high-pressure heater to heat the high-pressure feedwater in stages. Simultaneously, another extraction steam path enters the deaerator, where it mixes thoroughly with the feedwater in the spray-filler layer, achieving thermal deaeration and temperature increase. The controller continuously monitors the water level and pressure in the deaerator tank and adjusts the extraction steam flow to maintain it within the set range. At the same time, the controller determines whether the residual pressure and heat of the power generator's exhaust steam are usable. If the exhaust steam pressure is higher than the required driving pressure of the low-pressure heater, the controller opens the valve to the low-pressure heater, introducing low-temperature steam to preheat the condensate or primary feedwater. Throughout the process, the controller collects the outlet water temperature, condensate temperature, and steam side pressure of each stage of the heater, and adjusts the opening of each steam valve through closed-loop control to ensure that the feed water temperature gradually increases and is maintained within the preset temperature range.

[0084] In this embodiment, by introducing the extracted steam and exhaust steam from the power generator into the high-pressure heater, deaerator, and low-pressure heater respectively, the waste heat steam is utilized in stages, effectively maintaining the temperature stability of the feedwater system and improving the overall thermal energy utilization efficiency of the unit during the main turbine shutdown period.

[0085] like Figure 4 As shown, in some exemplary embodiments, controlling the main steam turbine to start includes:

[0086] Step 410: Monitor the high-pressure exhaust steam temperature during the main turbine start-up and grid connection process.

[0087] Step 420: By adjusting the steam flow rate entering the power generator, the reheat steam pressure is maintained at a preset low pressure value to control the high-pressure steam temperature from not exceeding the preset temperature.

[0088] Step 430: When the reheat steam pressure decreases and the driving force of the power generator is insufficient, control the motor to switch to electric motor mode.

[0089] During the main turbine's start-up and grid connection, the controller first collects the high-pressure exhaust steam temperature signal in real time through the temperature sensor at the high-pressure cylinder exhaust end and compares this data with the preset temperature safety limit. Simultaneously, the controller monitors the actual pressure value in the reheat steam pipeline to determine if it deviates from the set low-pressure target range. When the high-pressure exhaust steam temperature shows an upward trend or approaches the over-temperature threshold, the controller activates the pressure-temperature linkage control logic, calculates the required steam flow adjustment, and outputs a command to adjust the steam regulating valve opening of the power generator, increasing the steam inlet flow and thus consuming more reheat steam. This effectively suppresses the rise in reheat steam pressure, thereby controlling the high-pressure exhaust steam temperature to prevent it from exceeding the limit. Throughout this process, the controller continuously evaluates the operating status of the power generator and its driving capability for the feedwater pump. If the reheat steam pressure drops to a level that affects the normal output of the generator due to regulation, resulting in insufficient output power to meet the load requirements of the feedwater pump, the controller immediately determines that the driving force is insufficient and issues a mode switching command to switch the motor connected to the feedwater pump from generator mode or standby mode to motor mode. The motor is then powered by an external power source to drive the feedwater pump and ensure the stability of the boiler feedwater system.

[0090] In this embodiment, by monitoring the high-pressure exhaust steam temperature in real time during the main turbine's start-up and grid connection, and adjusting the steam flow of the power generator to maintain the reheat steam pressure at a preset low pressure value, the temperature rise during the start-up phase is effectively controlled, preventing the risk of overheating. At the same time, when the driving force is insufficient, the motor assistance is automatically activated, ensuring the continuous and stable operation of the feedwater system.

[0091] To provide a clearer explanation of the start-up and shutdown method for coal-fired power units based on a small power generator provided in this application, a specific embodiment is described below, which includes the following:

[0092] When the main steam turbine is shut down, the controller maintains boiler operation. The main steam generated by the boiler is desuperheated and depressurized via a high-pressure bypass and then divided into two streams. One stream enters the boiler's reheater, while the other stream passes through the turbine inlet valve and enters the power generator, driving its rotation. The controller then monitors the power generator's output power and the feedwater pump's load demand. The power generator drives the feedwater pump to supply water to the boiler to maintain water circulation. If the power generator's output power is insufficient to drive the feedwater pump, the controller switches the motor to electric motor mode for auxiliary drive. If the power generator's output power exceeds the feedwater pump's load demand, the controller switches the motor to generator mode to utilize excess energy for power generation. Simultaneously, the controller transmits the power... Steam extracted from the small turbine is introduced into the high-pressure heater and deaerator, while exhaust steam from the small power turbine is introduced into the low-pressure heater. Through the coordinated operation of the high-pressure heater, deaerator, and low-pressure heater, the feedwater temperature is maintained within a preset temperature range. Furthermore, during the main turbine's start-up and grid connection, the controller monitors the high-pressure exhaust steam temperature and adjusts the steam flow rate into the small power turbine to maintain the reheat steam pressure at a preset low pressure value, thus controlling the high-pressure exhaust steam temperature to not exceed the preset temperature. If the reheat steam pressure decreases, resulting in insufficient driving force for the small power turbine, the controller switches the motor to electric motor mode. Finally, upon receiving the main turbine start-up command and ensuring that the steam parameters generated by the boiler meet the preset main turbine start-up requirements, the controller starts the main turbine, initiating the grid-connected power generation process. In this embodiment, the rapid start-up and shutdown system diagram of the coal-fired power unit is shown below. Figure 5 As shown.

[0093] The above scheme achieves significant energy savings and efficiency improvements by optimizing energy utilization and equipment commissioning processes during unit startup. After boiler ignition, when the cold reheat steam pressure and temperature reach ~1MPa and ~300℃ and the steam quality is qualified, the steam source for the small turbine and auxiliary steam can be switched to the cold reheat (the pipeline of the cold section of the reheater) in advance. This saves fuel oil or steam consumption from adjacent units and reduces steam loss through the low-pressure bypass vent into the condenser. After the small turbine steam source is switched, the inlet steam regulating valve can be opened wider to reduce the power of the small generator in electric mode or even switch to power generation mode, recovering the energy lost in the original low-pressure bypass vent. At the same time, some high and low pressure heaters can be put into operation during the boiler ignition and blowdown stage to flush the steam side of the heaters in advance and improve the flushing effect of the water side, shortening the time for steam and water quality to meet the standards. Before grid connection, almost all heaters can be put into operation, and condensate can be recovered in advance, shortening the time from grid connection to full load operation. Furthermore, there is no need to design heating systems for adjacent units and boilers, further improving the start-up and shutdown speed.

[0094] During turbine start-up and shutdown, this solution effectively addresses the challenge of high-pressure exhaust steam temperature control. During main turbine startup and grid connection, maintaining a low reheat steam pressure is crucial to prevent high-pressure exhaust steam temperature from exceeding the limit. Traditional turbines rely on adjacent units or start-up / shutdown boilers for steam supply to the small turbine. However, with dual-unit reheating, even if the reheat steam pressure drops to 0.7 MPa or lower, the small generator can switch to electric mode to maintain stable turbine speed, significantly improving high-pressure exhaust steam temperature control. Furthermore, all heaters are put into operation before grid connection, raising the feedwater temperature to 150–170°C. Combined with measures such as a staged economizer, this meets the conditions for denitrification system activation, enabling full-load denitrification before grid connection. Conventional units, even with a No. 0 high-pressure heater, struggle to achieve this.

[0095] This solution also enhances the operational reliability and flexibility of units under deep-load conditions and contributes to the construction of new power systems. For units using steam pumps or electric pumps + steam pumps, there is no need to switch the small generator's steam source under deep-load conditions. Even if the reheat steam pressure drops rapidly, the small generator can maintain its speed by switching to electric mode, achieving seamless switching between steam pumps and electric pumps. This meets the demand for rapid load adjustment from 20% to 100%, avoiding the increased workload or the risk of tripping due to rapid load drops caused by switching steam sources. Simultaneously, this solution can improve the rapid start-up and shutdown capabilities of the Shagohuang supporting thermal power project and the new generation of coal-fired power plants, responding to the volatility of new energy sources and addressing the grid security risks brought about by randomness, thereby improving the capacity for new energy absorption. By increasing the absorption of new energy sources and reducing unit coal consumption, it reduces carbon consumption and carbon dioxide emissions, thus contributing to the construction of new power systems.

[0096] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0097] Based on the same inventive concept, this application also provides a power-based start-up and shutdown device for coal-fired power units, used to implement the aforementioned power-based start-up and shutdown method for coal-fired power units. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations in one or more power-based start-up and shutdown device embodiments provided below can be found in the limitations of the power-based start-up and shutdown method for coal-fired power units described above, and will not be repeated here.

[0098] In one exemplary embodiment, such as Figure 6 As shown, a start-stop device 600 for a coal-fired power unit based on a power generator is provided, deployed in a coal-fired power unit. The coal-fired power unit includes a boiler, a main steam turbine, a power generator, a motor, and a feedwater pump. The power generator is coaxially connected to the motor and the feedwater pump. The device includes: a first drive module 610, a second drive module 620, a heating control module 630, and a stroke control module 640, wherein:

[0099] The first drive module 610 is used to control the boiler to continue operating when the main steam turbine is shut down, and to drive the power generator through the steam generated by the boiler.

[0100] The second drive module 620 is used to drive the feedwater pump to supply water to the boiler via a power motor in order to maintain the water circulation of the boiler.

[0101] The heating control module 630 is used to heat the regenerating equipment in the feedwater pump by extracting or venting steam from the power generator in order to maintain the feedwater temperature.

[0102] The start-up control module 640 is used to control the main steam turbine to start up and enter the grid-connected power generation process when it receives the start-up command of the main unit and the steam parameters generated by the boiler meet the preset start-up requirements of the main unit.

[0103] In some embodiments, the first drive module 610 is further configured to divide the main steam generated by the boiler into two paths after bypassing the de-heating and de-pressure; one path of steam enters the boiler's reheater, and the other path of steam enters the power generator through the turbine inlet valve to drive the power generator to rotate.

[0104] In some embodiments, the apparatus further includes a steam control module for controlling the output steam from the reheater to be output through a heating valve when the main turbine is shut down; wherein the driving steam source for the power generator comes from the steam pipeline corresponding to the exhaust steam of the high-pressure cylinder of the main turbine or the steam pipeline after the bypass.

[0105] In one embodiment, the second drive module 620 is also used to monitor the output power of the power generator and the load demand of the water pump. When the output power of the power generator is insufficient to drive the water pump, the motor is controlled to switch to motor mode to assist in driving the water pump. When the output power of the power generator is greater than the load demand of the water pump, the motor is controlled to switch to motor mode to generate electricity using the excess energy.

[0106] In one embodiment, the heating control module 630 is used to introduce the extracted steam from the power generator into the high-pressure heater and the deaerator; to introduce the exhaust steam from the power generator into the low-pressure heater; and to maintain the feed water temperature of the feed water pump within a preset temperature range through the coordinated operation of the high-pressure heater, the deaerator and the low-pressure heater.

[0107] In one embodiment, the start-up control module 640 is used to monitor the high-pressure steam temperature during the start-up and grid connection of the main steam turbine; maintain the reheat steam pressure at a preset low pressure value by adjusting the steam flow rate entering the power generator, so as to control the high-pressure steam temperature not to exceed the preset temperature; and control the motor to switch to electric motor mode when the reheat steam pressure decreases and the driving force of the power generator is insufficient.

[0108] The modules in the aforementioned start-stop device for coal-fired power units based on a small power unit can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0109] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 7 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operating system and computer programs stored in the non-volatile storage media. The database stores data such as the operating status monitoring data of the coal-fired power unit and the output power of the power generator. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a coal-fired power unit start-up and shutdown method based on a power generator.

[0110] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0111] In one exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in any of the above embodiments of the coal-fired power unit start-up and shutdown method based on a power microcomputer.

[0112] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps in any of the above embodiments of the coal-fired power unit start-up and shutdown method based on a power microcomputer.

[0113] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in any of the above embodiments of the coal-fired power unit start-up and shutdown method based on a power microcomputer.

[0114] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0115] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0116] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0117] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for starting and stopping a coal-fired power unit based on a small power generator, characterized in that, The coal-fired power unit includes a boiler, a main steam turbine, a power generator, a motor, and a feedwater pump, wherein the power generator is coaxially connected to the motor and the feedwater pump, and the method includes: When the main steam turbine is shut down, the boiler is controlled to continue operating, and the steam generated by the boiler drives the power generator. The power generator drives the water pump to supply water to the boiler in order to maintain the water circulation of the boiler; The steam extracted or exhausted by the power generator is used to heat the regenerator in the water pump to maintain the water temperature. Upon receiving the host start command and if the steam parameters generated by the boiler meet the preset host start-up requirements, the main steam turbine is controlled to start up and enter the grid-connected power generation process.

2. The method for starting and stopping a coal-fired power unit based on a small power generator according to claim 1, characterized in that, The operation of the small electric motor driven by the steam generated by the boiler includes: The main steam generated by the boiler is divided into two streams after being de-heated and de-pressurized via a bypass. One stream of steam enters the reheater of the boiler, while the other stream of steam passes through the turbine inlet valve and enters the power generator to drive its rotation.

3. The method for starting and stopping a coal-fired power unit based on a small power generator according to claim 2, characterized in that, The method further includes: When the main steam turbine is shut down, the steam output from the reheater is controlled to be output through the heating valve; The driving steam source for the power generator comes from the steam pipeline corresponding to the exhaust steam of the high-pressure cylinder of the main steam turbine or the steam pipeline after the bypass.

4. The method for starting and stopping a coal-fired power unit based on a small power generator according to claim 1, characterized in that, The process of supplying water to the boiler by driving the feedwater pump through the power generator includes: Monitor the output power of the power generator and the load requirements of the water pump; If the output power of the power generator is insufficient to drive the water pump, the motor is controlled to switch to electric motor mode to assist in driving the water pump. When the output power of the power generator exceeds the load requirement of the water pump, the motor is controlled to switch to motor mode to generate electricity using the excess energy.

5. The method for starting and stopping a coal-fired power unit based on a small power generator according to any one of claims 1 to 4, characterized in that, The coal-fired power unit also includes a high-pressure heater, a deaerator, and a low-pressure heater; the heating of the regenerator in the feedwater pump by extracting or venting steam from the power generator includes: The extracted steam from the power generator is introduced into the high-pressure heater and deaerator; The exhaust steam from the aforementioned small power generator is introduced into the low-pressure heater; The water supply temperature of the feed water pump is maintained within a preset temperature range through the coordinated operation of the high-pressure heater, the deaerator, and the low-pressure heater.

6. The method for starting and stopping a coal-fired power unit based on a small power generator according to any one of claims 1 to 4, characterized in that, The control of the main steam turbine to start includes: During the main steam turbine's start-up and grid connection process, the high-pressure exhaust steam temperature is monitored; By adjusting the steam flow rate entering the power generator, the reheat steam pressure is maintained at a preset low pressure value to control the high-temperature exhaust steam temperature from exceeding the limit. When the reheat steam pressure decreases, causing insufficient driving force for the power generator, the motor is controlled to switch to electric motor mode.

7. A start-stop device for a coal-fired power unit based on a small power generator, characterized in that, Deployed in a coal-fired power unit, the coal-fired power unit includes a boiler, a main steam turbine, a power generator, a motor, and a feedwater pump, wherein the power generator is coaxially connected to the motor and the feedwater pump, and the device includes: The first drive module is used to control the boiler to continue operating when the main steam turbine is in a shutdown state, and to drive the power generator to run by the steam generated by the boiler. The second drive module is used to drive the feedwater pump to supply water to the boiler through the power motor, so as to maintain the water circulation of the boiler; The heating control module is used to heat the regenerator in the feedwater pump by extracting or venting steam from the power generator to maintain the feedwater temperature. The start-up control module is used to control the main steam turbine to start up and enter the grid-connected power generation process when it receives the start-up command of the main unit and the steam parameters generated by the boiler meet the preset start-up requirements of the main unit.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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