System for improving variable load capacity of subcritical pure condensed coal generator set

Abstract

The invention discloses a system for improving the variable load capacity of a subcritical pure condensed coal generator set, an external heat source is introduced through a direct heating device for active energy supplementation, and closed-loop control over the heating process is achieved through a controller. The method not only can dynamically maintain the parameters of the heat accumulator during the unit load increasing period, but also can be applied to the usual preheating and parameter maintaining process. In the load rising period, when the internal temperature and pressure of the heat accumulator are reduced due to the fact that the heat accumulator outputs a high-parameter working medium, the system can be started in real time or enhance heating and dynamically compensate energy loss, and therefore it is guaranteed that the parameters of the working medium in the heat accumulator are always stabilized in the rated high-parameter state. Under the normal working condition of non-rising load, the working medium in the heat storage tank can be actively heated and maintained in a high-temperature saturation state, so that the working medium is always in the optimal working condition of supplying energy at any time, and the problem of natural parameter attenuation caused by heat dissipation or storage of a traditional heat storage tank is effectively avoided.

Description

Technical Field

[0001] This application relates to the field of ternary energy storage technology, and in particular to a system for improving the load-changing capacity of subcritical pure condensing coal power units. Background Technology

[0002] According to industry development reports, subcritical units account for a significant portion of my country's coal-fired power capacity, but their operating efficiency is relatively low, coal consumption is high, and their flexible peak-shaving capacity is particularly insufficient. Improving the operational flexibility of these units has become a key weakness in the industry's emission reduction efforts and an urgent national need. To address this challenge, the industry has proposed technical routes such as "ternary lithium battery energy supply," aiming to overcome the unit's own response limits through the synergy of multiple energy storage methods. This approach typically includes three units: lithium batteries (fast power response), high-parameter working fluid accumulators (fast thermal response), and high-quality energy storage pulverized coal silos (fast fuel response), in order to collaboratively solve the response mismatch problem of fast turbine and slow furnace.

[0003] As a key thermodynamic response unit in a ternary energy storage system, the high-parameter working fluid accumulator plays a crucial role in rapidly replenishing the system with a high-parameter working fluid during the initial load ramp-up phase, when the boiler's main steam parameters have not yet increased due to significant thermal inertia. This rapidly enhances the turbine's work capacity. However, existing high-parameter working fluid accumulators often employ simple tank designs, relying on the unit's high-load operation for their internal working fluid parameters. During load ramp-up, when the accumulator releases the stored high-parameter working fluid, its internal temperature and pressure drop rapidly due to energy release, making it difficult to maintain the rated high-parameter state for the required duration. This leads to a rapid decline in energy supply quality, failing to sustainably and effectively support the entire rapid load ramp-up process, becoming a critical bottleneck restricting further improvements in the unit's overall load change rate. Summary of the Invention

[0004] Based on the above problems, this application provides a system for improving the load-changing capacity of subcritical pure condensing coal power units.

[0005] The embodiments of this application disclose the following technical solutions: The first aspect of this application provides a system for improving the load-changing capacity of subcritical pure condensing coal power units, including: High-parameter working fluid accumulators are used to store working fluids. A direct heating device is connected to the high-parameter working fluid accumulator and is used to heat the working fluid in the high-parameter working fluid accumulator through an external heat source so that the parameters of the working fluid are maintained at the rated high-parameter state consistent with the working fluid parameters of the unit's rated load. The controller is used to control the start-up and shutdown of the direct heating device and the heating power to maintain the working fluid in a rated high parameter state.

[0006] In one possible implementation, the system further includes: The high-quality energy storage pulverized coal silo is used to store pre-ground pulverized coal and supply coal to the furnace; the control system is used to control the coal supply rate of the high-quality energy storage pulverized coal silo.

[0007] In one possible implementation, the controller is used to activate the direct heating device to heat the working fluid in the heat accumulator in response to a load increase command until the working fluid reaches the rated high parameter consistent with the rated load working fluid parameter of the unit.

[0008] In one possible implementation, the controller is used to adjust or maintain the power output of the direct heating device when the temperature and pressure parameters reach and remain at the rated high parameter threshold, so as to stabilize the parameters of the working fluid at a rated high parameter state consistent with the rated load working fluid parameters of the unit.

[0009] In one possible implementation, the controller is configured to activate or increase the power output of the direct heating device when the temperature parameter and / or pressure parameter is lower than the rated high parameter threshold, so as to raise the working fluid parameter to the rated high parameter threshold.

[0010] In one possible implementation, the controller is configured to activate a direct heating device in response to a heating command to heat the working fluid in the heat storage tank until the working fluid reaches the rated high parameter consistent with the rated load working fluid parameter of the unit, wherein the heating command is configured to instruct the heat storage tank to be heated to a high temperature saturation state.

[0011] In one possible implementation, the direct heating device is integrated into or thermally connected to the high-parameter working fluid accumulator.

[0012] In one possible implementation, the system further includes a monitoring unit connected to the controller for monitoring the temperature and pressure parameters of the working fluid in the high-parameter working fluid accumulator; The controller is used to control the start-up and shutdown of the direct heating device and the heating power based on the parameters of the working fluid in the high-parameter working fluid accumulator, and during the process of increasing the unit load or heating the heat storage tank to a high-temperature saturation state, so as to maintain the working fluid in a rated high-parameter state.

[0013] In one possible implementation, the direct heating module uses flue gas heating, that is, it uses the waste heat of flue gas generated by the subcritical pure coal condensing generator to heat the working medium in the high-parameter working medium accumulator.

[0014] In one possible implementation, the direct heating module uses electric heating, that is, it converts electrical energy into heat energy through an electric heating device to heat the working fluid in the high-parameter working fluid accumulator.

[0015] In one possible implementation, the high-parameter working fluid accumulator is also used to inject the working fluid in the rated high-parameter state into the main working fluid system of the unit through a composite pipeline during the unit's load increase process, so as to improve the energy level of the main working fluid system.

[0016] Compared with the prior art, this application has the following beneficial effects: This application introduces an external heat source for active energy replenishment through a direct heating device and utilizes a controller to achieve closed-loop control of the heating process. This allows the system to activate or enhance heating in real time during unit load increases, dynamically compensating for energy losses when the internal temperature and pressure of the heat accumulator drops due to the output of high-parameter working fluid. This ensures that the working fluid parameters within the heat accumulator remain stable at the rated high parameter state. The system is also applicable under normal operating conditions without load increases, actively heating and maintaining the working fluid in the heat storage tank at a high-temperature saturation state, ensuring it is always in optimal operating condition for energy supply. This effectively avoids the natural parameter decay problem caused by heat dissipation or storage in traditional heat storage tanks. Through a coordinated system consisting of a high-parameter working fluid heat accumulator, a direct heating device, and a controller, the traditional heat accumulator is transformed from a static, passive heat storage unit into a dynamic, active, constant-temperature energy supply unit. This proactive maintenance capability overcomes the fatal flaw of traditional solutions where energy quality degrades with output, enabling the accumulator to continuously provide stable, high-quality working fluid throughout the critical period of boiler response lag, thus truly supporting the unit's rapid and continuous load change process. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of energy flow provided for an embodiment of this application; Figure 2 A flowchart illustrating the collaborative workflow between a high-parameter working fluid accumulator and the steam-water system of a pure coal condensing power unit. Figure 3 A schematic diagram of a structure provided for an embodiment of this application; Figure 4 This is another structural schematic diagram provided for an embodiment of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] To facilitate understanding of the technical solutions provided in the embodiments of this application, the technical terms involved in the embodiments of this application will be explained below.

[0021] Ternary energy storage refers to three energy storage and supply methods: lithium battery storage for power, high-parameter working fluid tank storage for heat, and high-quality small powder storage for chemical energy.

[0022] Variable load capacity refers to the ability of a unit to respond to changes in load within a unit of time, i.e., the magnitude of load increase or decrease within a unit of time.

[0023] Subcritical units: These are units where the highest temperature and pressure of the working fluid are slightly lower than the critical temperature and pressure.

[0024] Condensing turbine: A condensing turbine is a steam turbine generator set that primarily generates electricity and does not utilize thermal energy.

[0025] To facilitate understanding of the technical solutions provided in the embodiments of this application, the background technology involved in the embodiments of this application will be described below.

[0026] As mentioned earlier, most high-parameter working fluid accumulators in existing technologies are used as passive thermal storage tanks, and their internal working fluid parameters depend on the energy stored by the unit during high-load operation. During actual load increases, once the working fluid is released, the temperature and pressure inside the accumulator drop rapidly due to energy output, making it impossible to maintain the rated high parameters continuously within the required time window. This leads to a continuous degradation in the quality of the output working fluid, making it difficult to provide stable and effective thermal support throughout the rapid and continuous load increase process, thus becoming a key bottleneck restricting further improvement in the overall load-changing capacity of the unit.

[0027] To address the aforementioned issues, this application embodiment employs direct heating methods such as pulverized coal heating, electric heating, or flue gas heating to actively heat the high-parameter working fluid accumulator. This effectively overcomes the inherent defects of existing accumulators where the working fluid parameters rapidly decay and cannot maintain a high-parameter state when releasing energy. Consequently, the accumulator can continuously output high-quality working fluid at rated operating parameters and combine it with the unit's main working fluid for energy supply. This allows for rapid and continuous enhancement of the energy and flow rate of the steam-water system while the boiler has not yet reached the target parameters due to thermal inertia, ultimately significantly improving the unit's rapid load change and peak-shaving response capabilities.

[0028] It should be noted that this application provides a system for enhancing the variable load capacity of subcritical pure condensing coal-fired power units. It can be applied to the field of ternary energy storage technology. The above is merely an example and does not limit the application area of ​​the system for enhancing the variable load capacity of subcritical pure condensing coal-fired power units provided in this application.

[0029] It should be noted that the application of the direct heating technology provided in this application embodiment is not limited to the dynamic energy replenishment during the unit's load increase period. It is also applicable to normal operating conditions when the unit is not under load increase, and is used to heat the working fluid in the heat storage tank and maintain it in a high-temperature saturated state.

[0030] During the unit's load increase process, this application is used to compensate in real time for the decrease in internal parameters of the heat accumulator caused by the output of the working fluid, ensuring a continuous and stable supply of high-parameter working fluid. When the unit is operating at rated load, under reduced load, or in standby mode, the system can automatically activate the heating function based on the monitored working fluid parameters to overcome heat loss caused by environmental heat dissipation and other factors, thereby actively heating the working fluid in the heat storage tank to and maintaining it at a saturated state with rated high parameters for an extended period. This all-weather parameter maintenance capability ensures that the heat accumulator is always in an optimal ready-to-use state, fundamentally improving the reliability and agility of the unit's peak-shaving response. Therefore, the direct heating technology of this application is a comprehensive solution covering the entire life cycle of the heat accumulator (including daily temperature maintenance and preheating and transient energy supply compensation), effectively expanding the functional boundaries and application value of traditional heat storage devices.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] The following embodiment illustrates the system provided in this application for enhancing the variable load capacity of subcritical pure condensing coal power units.

[0033] The direct heating process design scheme based on a high-parameter working fluid accumulator provided in this application can be used for the load increase process of pure condensing coal-fired power units. The energy flow of a pure condensing coal-fired power unit is shown in the figure. Figure 1 This diagram illustrates the energy flow in an embodiment of this application. The pulverizing system provides chemical energy (from pulverized coal fuel), which is the initial energy source for the unit. The chemical energy from the pulverizing system is input into the boiler and converted into heat energy through combustion, providing the energy basis for subsequent work by the working fluid. The heat energy generated by the boiler is transferred to the steam-water system, enabling the working fluid (water / steam) within the system to acquire internal energy (manifested as parameters such as temperature and pressure). The internal energy of the working fluid in the steam-water system drives the turbine, converting the internal energy into mechanical energy. The mechanical energy of the turbine drives the generator, ultimately converting it into electrical energy output by the unit.

[0034] Figure 2 This diagram illustrates the collaborative workflow between a high-parameter working fluid accumulator and the steam-water system of a pure condensing coal-fired power unit. It characterizes the working fluid storage, parameter maintenance, and energy supply coordination logic of the accumulator under different unit operating conditions. The closed-loop design, encompassing heat storage, heating, and load regulation, provides crucial support for rapid load changes in the unit. The process centers on a high-parameter working fluid accumulator tank. Through pipeline connections to the unit's steam drum, superheater, and related valves and pumps, it achieves bidirectional flow regulation of the working fluid between the unit system and the accumulator tank. The accumulator tank consistently stores a high-parameter working fluid with parameters consistent with the unit's rated load, ensuring energy supply compatibility and effectiveness. The operating modes include the following: First, when the unit is at its rated power generation load, the working fluid in the steam drum that meets the rated parameter standards will be transported to the heat accumulator for storage through a pre-set pipeline. At this time, the temperature, pressure and other operating parameters of the working fluid in the heat accumulator are the rated operating parameters set by the system, thus completing the basic heat storage reserve.

[0035] Secondly, when the unit enters the load reduction phase, the heat accumulator switches to working fluid recovery mode. Through the coordinated control of valves and pumps, some of the working fluid inside the steam drum is introduced into the tank for storage, which quickly reduces the flow of working fluid entering the steam turbine, thereby achieving a rapid reduction in the generator's power output and improving the load reduction response efficiency.

[0036] To prevent the working fluid's parameters from decreasing due to heat dissipation or changes in operating conditions during storage, this application incorporates an active heating mechanism. This mechanism can flexibly heat the accumulator through various methods such as pulverized coal combustion, electric heating, and flue gas heating, ensuring the working fluid inside the tank maintains its rated high parameters and providing stable energy supply for subsequent load increases. When the unit receives a load increase command, the accumulator immediately activates its energy supply mode, rapidly delivering the high-parameter working fluid from the tank to the steam-water system. After combining with the unit's existing working fluid, this significantly improves the working fluid parameters and flow rate of the steam-water system. This combined working fluid, after being conditioned by the accumulator, enters the turbine, providing additional mechanical energy to the turbine. This directly drives the generator to generate additional electricity, rapidly increasing the unit's load and ultimately achieving the goal of rapid load change. This effectively solves the problem of delayed load change response caused by boiler thermal inertia in traditional units.

[0037] The core of this application's embodiment lies in directly heating the high-parameter working fluid accumulator through an external heat source, ensuring that the stored working fluid is always in its rated high-parameter state. The advantage of the high-parameter working fluid tank is that while its size and energy storage capacity are not large, it can meet the energy demands of a load increase when the unit requires it, especially when pulverized coal cannot be supplied quickly enough or the steam drum pressure and temperature cannot rise promptly. It rapidly adjusts the working fluid circulation state, effectively reducing the effects of boiler thermal inertia and shortening the steam-water system response time. Therefore, maintaining the high-parameter state of the high-parameter working fluid accumulator is crucial.

[0038] like Figure 3 As shown, Figure 3 This is a schematic diagram of a structure provided in an embodiment of the present application, wherein the direct heating device is integrated on the high-parameter working fluid accumulator or thermally connected to the high-parameter working fluid accumulator.

[0039] The first type involves directly integrating the heating device into the high-parameter working fluid accumulator. This means the heating device is physically integrated with the accumulator, typically in a built-in or tightly attached design. Built-in integration involves placing the heating element (such as an electric heating rod, coil burner, or heat exchange tube) directly within the accumulator's internal cavity, immersing it in the working fluid or adhering it to the inner wall. Heat is directly transferred to the working fluid via conduction or radiation, resulting in minimal heat loss and rapid response. External wall integration involves tightly fixing or welding the heating component, such as a strip heater, jacketed combustion chamber, or heat exchange chamber welded to the outer wall, to the accumulator's outer surface. Heat is conducted to the internal working fluid through the wall; the structure is relatively independent but still part of the accumulator. This integration method emphasizes structural unity, offering advantages such as a short heat transfer path, high efficiency, compact system, and strong overall integrity. For example, the electric heating wire can be wound and encapsulated within the accumulator wall, or the miniature combustion chamber and the accumulator shell can be designed as a single pressure-bearing unit.

[0040] The second type involves direct thermal connection between the heating device and the high-parameter working fluid accumulator. This method refers to the heating device acting as an independent module, establishing an efficient heat transfer channel with the accumulator through a heat transfer medium or interface. Pipeline-type thermal connection involves the heating device (such as an independent combustion furnace, flue gas heat exchanger, or steam heater) generating a high-temperature medium (such as hot flue gas, high-temperature steam, or thermal oil). This medium is transported through pipelines to heat exchange units (such as coils or jackets) connected to the inside or outside of the accumulator, thereby heating the working fluid. Interface-type thermal connection involves the heating device and the accumulator directly contacting each other through a thermally conductive surface (such as a large-area heat-conducting plate with flange connections), achieving heat conduction across the equipment interface. This thermal connection method emphasizes functional coupling and modularity. Its advantages include the ability to independently arrange the heating device, ease of maintenance and replacement, and flexible selection of heat source types (e.g., the ability to remotely arrange combustion systems to isolate hazardous sources). Although both are separate structures, a specially designed heat transfer path ensures effective heat delivery.

[0041] Both methods serve the same core purpose: to achieve active, controllable, and direct heating of the working fluid within the high-parameter working fluid accumulator through an external heat source, thereby ensuring a continuous output of high-quality working fluid that meets rated parameter requirements during peak shaving, providing crucial energy support for rapid load changes. In actual system design, these two methods can be selected or combined based on specific engineering constraints (such as space layout, heat source type, maintenance requirements, etc.).

[0042] The entire process adapts to multiple scenarios, including rated load heat storage, load reduction heat recovery, active heating to stabilize parameters, and load increase energy supply, achieving efficient recycling of the working fluid. At the same time, relying on flexible heating methods and precise parameter matching, it provides stable and rapid energy support for the unit's load change process, making it a core component in the ternary energy storage system to improve the unit's peak-shaving flexibility.

[0043] The following example illustrates in detail the working principle of this system during rapid load increase. The example scenario assumes a pure condensing coal-fired power unit is currently operating at load X (e.g., 50% of rated power). According to grid dispatch instructions, it needs to be rapidly increased to the target load Y (e.g., 85% of rated power). To achieve this rapid load increase, the high-quality energy storage silo and high-parameter working fluid accumulator equipped in the system will operate collaboratively, addressing the response lag issues on the fuel and thermal sides respectively. The entire process can be divided into four sequentially connected stages. Through time relay and energy complementarity, the system ultimately achieves a smooth, rapid, and controllable load increase.

[0044] See Figure 4 , Figure 4This is another structural diagram provided for an embodiment of the present application. It shows the working logic of a high-parameter working fluid heat storage tank maintaining working fluid parameters through a direct heating device and being coupled with the unit's steam-water system. The high-parameter working fluid heat storage tank, as an energy storage unit, is connected to core equipment such as the unit's steam drum and superheater through pipelines to achieve bidirectional transport of the working fluid. The direct heating device is associated with the heat storage tank and is used to supplement the working fluid in the tank with heat to maintain its high parameters consistent with the unit's rated load. The main equipment of the unit includes a steam drum, furnace heat exchange equipment (including furnace walls and heating surfaces), superheater, economizer, air preheater, and steam turbine, constituting the energy conversion process of a conventional pulverized coal unit.

[0045] The first stage is command triggering and rapid startup.

[0046] When a subcritical pure condensing coal power unit receives an instruction to increase its load from the current load X to the target load Y, the load increase process begins immediately. To overcome the enormous thermal inertia of the boiler system, the system first simultaneously activates two key actions. On one hand, the high-quality energy storage pulverized coal silo instantaneously injects pre-prepared fine coal powder into the boiler furnace, causing the fuel input rate to far exceed the conventional ramp-up curve in an instant, forcibly increasing the furnace heat load. On the other hand, the direct heating device (such as an electric heater or burner) of the high-parameter working fluid accumulator is activated, actively and rapidly heating the pre-stored working fluid inside, causing its temperature and pressure to quickly climb to the high-parameter state required for the unit's rated operation. The time from the issuance of the instruction to the working fluid in the accumulator reaching the target parameters constitutes the first stage of the entire rapid load increase chain, namely the energy preparation startup stage.

[0047] The second stage involves the rapid increase in load and the supply of energy from the heat storage device.

[0048] As the working fluid in the accumulator reaches a high-parameter state, the system enters the core power boost phase. At this time, although the small coal silo has begun rapid coal supply, the output of the unit's main coal mill system increases relatively slowly, and the total fuel supply is still catching up with the target value. To compensate for the lag in the rise of the boiler's main steam parameters, the high-parameter working fluid accumulator begins to continuously inject its high-parameter working fluid into the main steam-water system through a dedicated pipeline. This high-energy working fluid, after mixing with the currently low-parameter working fluid produced by the boiler, significantly improves the overall energy quality of the working fluid entering the turbine, enabling the turbine to immediately obtain additional power far exceeding the current boiler supply capacity. Therefore, the generator output power increases rapidly and linearly.

[0049] The period from the start of load ramp-up to when the generator's actual power reaches the target value Y is defined as the second stage, a critical stage for achieving rapid load response through external energy storage. At the end of this stage, the generator's actual power output has reached the target load Y. This stage covers the entire rapid ramp-up period from the start of load ramp-up to when the generator power reaches Y.

[0050] The third stage involves stabilizing power output and catching up with boiler parameters.

[0051] When the generator power reaches the target load Y first, the boiler, due to its enormous thermal inertia, still fails to reach the rated values ​​of heat output and flow rate of the working fluid that match the load Y. At this point, the system enters the power stabilization phase. The high-parameter working fluid accumulator continues to supply high-parameter working fluid to the main system to maintain the turbine inlet working fluid parameters at the rated level, thereby ensuring that the generator power remains stable at the target value Y and preventing a power drop due to boiler parameter fluctuations. Simultaneously, the high-quality pulverized coal storage silo continues to operate to compensate for the insufficient output of the main coal pulverizer system. The period from when the generator reaches the target load Y until the boiler output working fluid parameters finally catch up with the rated values ​​is designated as the third stage. This stage begins when the generator reaches Y and ends when the boiler output working fluid heat and flow rate reach the rated operating conditions matching Y. This stage resolves the power stabilization problem inherent in the "fast generator, slow boiler" issue.

[0052] The fourth stage is parameter balancing and power stabilization.

[0053] Finally, after continuous combustion and heat transfer, the boiler's working fluid parameters fully reached the rated operating conditions matching the target load Y. At this point, the rapid load increase was complete, and the system needed to smoothly switch back to the conventional steady-state operation mode. The high-parameter working fluid accumulator first stopped supplying working fluid, and its heating device switched to standby or heat preservation mode. Subsequently, the output of the conventional coal mill system increased to meet the load Y requirement, and the high-quality energy storage pulverized coal silo stopped supplying coal. The unit maintained stable operation at the target load Y entirely relying on its own boiler system. The accumulator can re-store heat at a suitable time later, preparing for the next peak shaving.

[0054] In one possible implementation, the core function of the controller is to implement precise and dynamic closed-loop control of the direct heating device based on the real-time state of the working fluid in the high-parameter working fluid accumulator and the unit's operating requirements, so as to ensure that the working fluid in the accumulator is always in the rated high-parameter state that can be supplied for output.

[0055] On the one hand, the controller can respond to load increase commands by activating or enhancing the direct heating device during rapid load increases in the unit. This dynamically compensates for the decrease in internal parameters of the heat accumulator caused by the output working fluid, ensuring continuous and stable energy supply quality. On the other hand, the controller can also respond to independent heating commands. These commands instruct the direct heating device to be activated to heat or maintain the working fluid in the heat accumulator during normal operating conditions (e.g., steady-state operation, standby, or load reduction) until the working fluid reaches and is maintained at the high-temperature saturation state corresponding to the unit's rated load. Thus, the application scenarios of direct heating technology are comprehensively expanded: it is not only used for real-time energy compensation during load increases but also actively maintains the parameter levels of the heat accumulator during daily operation, ensuring it remains in a rated high-parameter state ready for immediate operation. This significantly improves the reliability and agility of the entire system in peak-shaving response.

[0056] Its control logic mainly covers the following three typical operating conditions, which together constitute a complete monitoring-judgment-regulation control loop: First, under steady-state operation, when the monitoring unit indicates that the temperature and pressure parameters of the working fluid within the accumulator have reached and stabilized within the preset rated high parameter threshold range, the controller does not simply shut down the heating. Instead, it switches to a precise power regulation or maintenance mode. At this point, the controller aims to overcome the natural heat loss from the accumulator to the environment and offset any parameter drops that may be caused by minor leaks or thermal fluctuations. Therefore, it adjusts (e.g., reduces) or maintains a lower power output from the direct heating unit to dynamically balance heat input and loss, thereby keeping the working fluid parameters consistently at a high level consistent with the unit's rated load working fluid parameters over a long period. This ensures that the accumulator is always in a "ready" state.

[0057] Secondly, under parameter compensation conditions, when the monitoring unit detects that the temperature and / or pressure parameters of the working fluid are lower than the set rated high parameter threshold (e.g., during the initial energy storage phase, or due to a drop in internal parameters after the working fluid is output), the controller will immediately take remedy measures. Depending on the magnitude of the parameter deviation, it will activate the direct heating device that is currently off, or increase the power output of the heating device that is already in operation. By applying a stronger or restarted heat input, the working fluid parameters are actively and quickly raised back to the rated high parameter threshold. This mode ensures that the heat accumulator can rapidly recover to a usable high parameter level after consumption or in its initial state.

[0058] Finally, under the trigger condition, this control logic is directly linked to the unit's load increase action. When the system responds to the load increase command, regardless of the current parameters of the working fluid in the accumulator, the controller will immediately activate the direct heating device to heat the working fluid. Its control objective is a clearly defined time-limited requirement: within the window period required for the load increase process, continuous heating until the working fluid parameters are confirmed to reach the rated high parameter state. This provides a preliminary guarantee for the accumulator to output high-quality working fluid in a timely manner to support the rapid response of the steam-water system.

[0059] In summary, the control strategy provided in this application achieves full-condition coverage of the high-parameter working fluid accumulator, from steady-state maintenance to deficit compensation and command triggering. This demonstrates that the controller not only possesses simple on / off functions but also intelligently judges and dynamically adjusts power based on real-time parameters and external commands.

[0060] This application also provides corresponding equipment and computer storage media for implementing the system provided in this application for improving the variable load capacity of subcritical pure condensing coal power units.

[0061] The device includes a memory and a processor. The memory stores instructions or code, and the processor executes the instructions or code to enable the device to perform the system for improving the variable load capacity of subcritical pure condensing coal power units as described in any embodiment of this application.

[0062] The computer storage medium stores code. When the code is executed, the device running the code implements the system for improving the variable load capacity of subcritical pure condensing coal power units as described in any embodiment of this application.

[0063] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0064] It should be understood that in this application, "at least one" refers to one or more items, and "more" refers to two or more items. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one" of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0065] It should be understood that the terms center, longitudinal, transverse, up, down, front, back, left, right, vertical, horizontal, top, bottom, inside, outside, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0066] It should be noted that, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0067] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the statement "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for enhancing the variable load capacity of subcritical pure condensing coal power units, characterized in that, include: High-parameter working fluid accumulators are used to store working fluids. A direct heating device is connected to the high-parameter working fluid accumulator and is used to heat the working fluid in the high-parameter working fluid accumulator through an external heat source so that the parameters of the working fluid are maintained at the rated high-parameter state consistent with the working fluid parameters of the unit's rated load. The controller is used to control the start-up and shutdown of the direct heating device and the heating power to maintain the working fluid in a rated high parameter state.

2. The system according to claim 1, characterized in that, The system also includes: The high-quality energy storage pulverized coal silo is used to store pre-ground pulverized coal and supply coal to the furnace; the control system is used to control the coal supply rate of the high-quality energy storage pulverized coal silo.

3. The system according to claim 1, characterized in that, The controller is used to respond to a load increase command by activating the direct heating device to heat the working fluid in the heat accumulator until the working fluid reaches the rated high parameter consistent with the rated load working fluid parameter of the unit.

4. The system according to claim 1, characterized in that, The controller is used to adjust or maintain the power output of the direct heating device when the temperature and pressure parameters reach and are maintained at the rated high parameter threshold, so that the parameters of the working fluid are stabilized at the rated high parameter state consistent with the rated load working fluid parameters of the unit.

5. The system according to claim 1, characterized in that, The controller is used to activate or increase the power output of the direct heating device when the temperature parameter and / or pressure parameter is lower than the rated high parameter threshold, so as to raise the working fluid parameter to the rated high parameter threshold.

6. The system according to claim 1, characterized in that, The controller is used to respond to a heating command by activating a direct heating device to heat the working fluid in the heat storage tank until the working fluid reaches the rated high parameter consistent with the rated load working fluid parameter of the unit. The heating command is used to instruct the heat storage tank to be heated to a high temperature saturation state.

7. The system according to claim 1, characterized in that, The direct heating device is integrated into the high-parameter working fluid accumulator or is thermally connected to the high-parameter working fluid accumulator.

8. The system according to claim 1, characterized in that, The system also includes a monitoring unit connected to the controller, used to monitor the temperature and pressure parameters of the working fluid in the high-parameter working fluid accumulator; The controller is used to control the start-up and shutdown of the direct heating device and the heating power based on the parameters of the working fluid in the high-parameter working fluid accumulator, and during the process of increasing the unit load or heating the heat storage tank to a high-temperature saturation state, so as to maintain the working fluid in a rated high-parameter state.

9. The system according to claim 1, characterized in that, The direct heating module uses flue gas heating, which utilizes the waste heat from the flue gas generated by the subcritical pure coal condensing generator to heat the working fluid in the high-parameter working fluid accumulator.

10. The system according to claim 1, characterized in that, The direct heating module uses electric heating, which converts electrical energy into heat energy through an electric heating device to heat the working fluid in the high-parameter working fluid accumulator.

11. The system according to claim 1, characterized in that, The high-parameter working fluid accumulator is also used to inject the working fluid, which is in a rated high-parameter state, into the main working fluid system of the unit through a composite pipeline during the unit's load increase process, so as to improve the energy level of the main working fluid system.

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