Method and device for improving economical efficiency of low-load steam turbine, electronic equipment and storage medium

Abstract

The invention relates to the technical field of thermal power plant steam turbines, in particular to a method and device for improving the economical efficiency of a low-load steam turbine, electronic equipment and a storage medium. And solar fluctuation is dynamically adjusted based on a heat storage system in the solar steam generation system, the wet steam running time of the low-pressure cylinder is shortened, meanwhile, the heat storage system is dynamically controlled, and the opening degree of a water supply valve and the flow of heat conduction oil are adjusted to adapt to load changes. According to the method, the coal consumption is reduced, the emission pollution is reduced, the energy utilization efficiency is improved, the deep peak regulation capacity is enhanced, and the low-load economy and the system stability are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbines in thermal power plants, and in particular to a method, a device, an electronic device and a storage medium for improving the economy of a low-load steam turbine. Background Art

[0002] With the rapid development of renewable energy installations and increasing demand for grid peak regulation, coal-fired units are increasingly shouldering the responsibility of deep peak regulation. However, under low-load conditions, the turbine's low-pressure cylinder (LPC) experiences significant increases in heat rate, a sharp decline in economic efficiency, and reduced safety due to reduced steam flow, increased humidity, and deteriorating flow in the last-stage blades. Existing solutions require significant investment to redesign the turbine itself. While CSP offers greater stability, the investment cost is prohibitive and difficult to scale. During periods of high solar irradiation, coal-fired units enter deep peak regulation, while CSP reaches high output, creating a temporally complementary relationship between the two. Both CSP and coal-fired units convert energy first into heat and then into electricity, sharing common conversion pathways and potentially overlapping in space. Therefore, an economic optimization solution is urgently needed that can both improve LP CC efficiency under low loads and achieve efficient spatial and temporal synergy between solar and coal-fired units. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a method, device, electronic equipment, and storage medium for improving the economy of a low-load steam turbine.

[0004] In a first aspect, an embodiment of the present invention provides a method for improving the economic efficiency of a low-load steam turbine. The method is applied to a coupled system, wherein the coupled system includes a solar steam generation system and a coal-fired unit, wherein the feedwater valve inlet of the solar steam generation system is connected to a bypass of a designated low-temperature heater in the coal-fired unit. The method comprises:

[0005] When the coal-fired unit enters deep peak-shaving operation, the solar steam generation system is turned on to generate superheated steam;

[0006] Dynamically control the heat storage system in the solar steam generation system based on solar radiation intensity and load changes of coal-fired units;

[0007] The superheated steam generated by the solar steam generation system is introduced into the pressure equalizing tank and mixed with the exhaust steam from the intermediate pressure cylinder of the coal-fired unit to adjust the mixed steam pressure and match the inlet pressure of the low pressure cylinder of the coal-fired unit;

[0008] According to the load changes of the coal-fired unit, the feed water valve opening and the thermal oil flow rate are adjusted to make the solar steam supplement amount adapt to the needs of the low-pressure cylinder and maintain the load of the low-pressure cylinder in the high-efficiency range.

[0009] In combination with the first aspect, the steps of dynamically controlling the heat storage system in the solar steam generation system based on the solar radiation intensity and the load change of the coal-fired unit include:

[0010] When solar radiation increases and the load of coal-fired units decreases, excess solar heat is converted into sensible heat or latent heat of the heat storage medium through the heat storage heat exchanger;

[0011] When solar radiation weakens and the load of the coal-fired unit recovers, the heat of the heat storage medium is released through the heat storage heat exchanger to maintain the temperature of the thermal oil.

[0012] In combination with the first aspect, the solar steam generation system further includes a concentrator, and the method includes:

[0013] Get the current solar radiation intensity;

[0014] If the current solar radiation intensity reaches a first preset threshold, the concentrating mirror is driven to concentrate light, and the heat transfer oil is driven to flow in the heat collection device, and the heat transfer oil is heated by concentrated heating;

[0015] When the current solar radiation intensity meets the heat loss, the circulation pump in the solar steam generation system is started to introduce all the heated thermal oil into the heat storage heat exchanger, and heat exchange is performed with the heat storage medium to store the heat in the high-temperature heat storage tank.

[0016] In combination with the first aspect, after the step of obtaining the current solar radiation intensity, the method further includes:

[0017] Calculate the solar radiation enhancement rate based on the current solar radiation intensity and the previous solar radiation intensity;

[0018] If the solar radiation enhancement rate for the first number of consecutive times is greater than the preset rate threshold, the rotation speed of the heat transfer fluid pump is increased to increase the heat collection amount of the heat collecting device, thereby increasing the heat storage amount of the high-temperature heat storage tank.

[0019] In combination with the first aspect, the method further includes:

[0020] If the coal-fired unit receives a load reduction instruction, it is triggered to enter a deep peak load regulation state;

[0021] When the load deviation of the coal-fired unit and the load of the coal-fired unit entering the deep peak load regulation condition is less than the threshold, the water supply valve and the branch valve are switched from the closed state to the open state, so that part of the thermal oil is diverted to the superheating section and the evaporation section, and at the same time, part of the water is introduced into the low-temperature heater bypass;

[0022] Gradually increase the opening and closing angles of the water supply valve and the branch valve until the heat collected by the heat collector is completely transferred to the accumulated water led out of the low-temperature heater bypass and passed into the low-pressure cylinder.

[0023] In combination with the first aspect, after the step of obtaining the current solar radiation intensity, the method further includes:

[0024] When the current solar radiation intensity is less than a second preset threshold, the concentrating mirror is driven to stop rotating, and the speed of the thermal fluid pump is gradually reduced to gradually stop the flow of the thermal oil in the heat collecting device;

[0025] At the same time, the circulation pump driving the high-temperature heat storage tank and the low-temperature heat storage tank is turned on to drive the heat storage cutoff to flow through the heat storage heat exchanger for heat exchange;

[0026] The second preset threshold is smaller than the first preset threshold.

[0027] In combination with the first aspect, after the step of calculating the solar radiation increase rate based on the current solar radiation intensity and the previous solar radiation intensity, the method further includes:

[0028] If the solar radiation enhancement rate for a second number of times in a row is less than the preset rate threshold, the rotation speed of the heat transfer fluid pump is reduced to reduce the amount of heat collected by the heat collecting device, thereby reducing the amount of heat stored in the high-temperature heat storage tank.

[0029] In a second aspect, the present application provides a device for improving the economic efficiency of a low-load steam turbine, comprising:

[0030] The generation module is used to open the water supply valve and thermal oil circuit of the solar steam generation system when the coal-fired unit enters deep peak-shaving operation, introduce water supply from the coal-fired unit's low-temperature heater bypass, and perform countercurrent heat exchange through the preheating section, evaporation section, and superheating section to generate superheated steam;

[0031] A control module for dynamically controlling the heat storage system in the solar steam generation system based on changes in solar radiation intensity and coal-fired unit load;

[0032] The mixing module is used to introduce the superheated steam generated by the solar steam generation system into the pressure equalizing tank, mix it with the exhaust steam from the intermediate pressure cylinder of the coal-fired unit, and adjust the pressure of the mixed steam through the pressure equalizing tank to match the inlet pressure of the low-pressure cylinder;

[0033] The adjustment module is used to adjust the feedwater valve opening and thermal oil flow according to the load changes of the unit, so that the solar steam supplement amount can adapt to the demand of the low-pressure cylinder and maintain the low-pressure cylinder load in the high-efficiency range.

[0034] In a third aspect, the present application provides an electronic device, which includes a memory and a processor. The memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the above method.

[0035] In a fourth aspect, the present application provides a readable storage medium, in which computer program instructions are stored. When the computer program instructions are read and executed by a processor, the above-mentioned method is executed.

[0036] The embodiments of the present invention bring the following beneficial effects: the present application provides a method, device, electronic equipment, and storage medium for improving the economy of a low-load steam turbine, the method being applied to a coupling system, the coupling system comprising a solar steam generation system and a coal-fired unit, the feedwater valve inlet of the solar steam generation system being connected to a bypass of a designated low-temperature heater in the coal-fired unit; the method comprising: when the coal-fired unit enters a deep peak-shaving operating condition, turning on the solar steam generation system to generate superheated steam; dynamically controlling the heat storage system in the solar steam generation system based on the solar radiation intensity and the load changes of the coal-fired unit; introducing the superheated steam generated by the solar steam generation system into a pressure equalizing tank, and mixing it with the exhaust steam of the intermediate-pressure cylinder in the coal-fired unit to adjust the mixed steam pressure and match the inlet pressure of the low-pressure cylinder in the coal-fired unit; adjusting the feedwater valve opening and the thermal oil flow rate according to the load changes of the coal-fired unit, so that the solar steam supplement amount adapts to the needs of the low-pressure cylinder, and maintains the load of the low-pressure cylinder in the high-efficiency range.

[0037] This method couples a solar steam generation system with a coal-fired unit, generating supplemental steam through the solar steam generation system to maintain the coal-fired unit's low-pressure cylinder in the high-efficiency range under low load. The solar steam generation system's heat storage system dynamically adjusts solar energy fluctuations to reduce the wet steam operation time of the low-pressure cylinder. Simultaneously, the heat storage system is dynamically controlled, adjusting the feedwater valve opening and thermal oil flow rate to adapt to load fluctuations. This method reduces coal consumption, lowers emissions, improves energy efficiency, enhances deep peak-shaving capabilities, and significantly improves low-load economy and system stability.

[0038] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purposes and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 A flow chart of a method for improving the economic efficiency of a low-load steam turbine provided by an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a device for improving the economic efficiency of a low-load steam turbine provided by an embodiment of the present invention;

[0043] Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of the structure of a solar steam generation system coupled with a coal-fired unit provided in an embodiment of the present invention.

[0045] Reference numerals:

[0046] 10-generation module, 20-control module, 30-mixing module, 40-adjustment module;

[0047] 130 - processor, 131 - memory, 132 - bus, 133 - communication interface. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0049] To facilitate understanding of this embodiment, the following is a brief introduction to the technical terms used in this application.

[0050] A coal-fired unit is a power generation system that uses coal as fuel, generating heat through combustion and converting it into electricity. Its main components include a boiler, a steam turbine, and a generator. Coal combustion in the boiler heats water into high-temperature, high-pressure steam. This high-temperature, high-pressure steam enters the turbine, rotating blades and converting thermal energy into mechanical energy. This mechanical energy is then transferred to the generator through a coupling, driving it to generate electricity, completing the conversion of mechanical energy into electrical energy.

[0051] A solar steam generation system uses solar energy to heat water to high temperature and pressure, thereby producing steam. Its main components include a solar collector, a heat transfer medium (such as thermal oil or molten salt), and a heat exchanger. The solar collector absorbs solar radiation and transfers heat to the heat transfer medium, which then transfers the heat absorbed by the collector to the steam generator. The heat transfer medium then transfers the heat to the water in the heat exchanger, evaporating the water into high-temperature, high-pressure steam for subsequent use.

[0052] After introducing the technical terms involved in this application, the application scenarios and design concepts of the embodiments of this application are briefly introduced.

[0053] With the rapid growth of renewable energy installed capacity and the increasing demand for peak-shaving capacity in the power grid, coal-fired units have gradually been assigned the task of deep peak-shaving. However, under low-load operating conditions, the heat rate of the low-pressure cylinder of the steam turbine increases significantly and its economic efficiency decreases significantly due to problems such as reduced steam flow, increased humidity, and deterioration of flow in the last-stage blades. Among the current solutions, redesigning the turbine body requires huge capital investment; and although solar thermal power generation has high stability, its investment cost is too high and it is difficult to achieve large-scale application. In addition, traditional solar-coal complementary systems mostly use a series heating method, which will lead to reduced boiler efficiency. Therefore, there is an urgent need for an optimization solution that can not only improve the efficiency of the low-pressure cylinder under low-load conditions, but also achieve efficient coordinated operation of solar energy and coal-fired units and have economic feasibility.

[0054] Based on this, the embodiments of the present application provide a method, device, electronic equipment, and storage medium for improving the economy of a low-load steam turbine.

[0055] Example 1

[0056] This application provides a method for improving the economy of low-load steam turbines, which is applied to coupling systems and combined with Figure 4 As shown, the coupled system includes a solar steam generation system and a coal-fired unit, wherein the feedwater valve inlet of the solar steam generation system is connected to the bypass of a designated low-temperature heater in the coal-fired unit; the solar steam generation system also includes a thermal oil circuit, a heat storage system, a heat collection device and a pressure equalizing tank; the coal-fired unit also includes a medium-pressure cylinder, a low-pressure cylinder, a deaerator, a low-temperature heater, a feedwater valve and a condenser; combined Figure 1 As shown, the method includes:

[0057] S110: When the coal-fired unit enters the deep peak regulation mode, the solar steam generation system is turned on to generate superheated steam.

[0058] S120 dynamically controls the heat storage system in the solar steam generation system based on the solar radiation intensity and the load changes of the coal-fired units.

[0059] S130, introduces the superheated steam generated by the solar steam generation system into the pressure equalizing tank and mixes it with the exhaust steam of the intermediate pressure cylinder in the coal-fired unit to adjust the mixed steam pressure and match the inlet pressure of the low pressure cylinder in the coal-fired unit.

[0060] S140, according to the load changes of the coal-fired unit, adjusts the feedwater valve opening and the thermal oil flow rate to make the solar steam supplement amount adapt to the needs of the low-pressure cylinder and maintain the load of the low-pressure cylinder in the high-efficiency range.

[0061] The present application provides a method for improving the economic efficiency of a low-load steam turbine, which is applied to a coupled system. The coupled system includes a solar steam generation system and a coal-fired unit. The feedwater valve inlet of the solar steam generation system is connected to the bypass of a designated low-temperature heater in the coal-fired unit. The solar steam generation system also includes a thermal oil circuit, which uses the solar steam generation system to generate superheated steam and mixes it with the exhaust steam of the intermediate pressure cylinder. After the pressure is adjusted by the pressure equalizing tank, the low-pressure cylinder load is supplemented. At the same time, the heat storage system (including Figure 4 The system can adjust the feedwater valve opening and thermal oil flow rate to adapt to load changes. This method reduces coal consumption, lowers emissions, improves energy efficiency, enhances deep peak load regulation capabilities, and significantly improves economic efficiency and system stability.

[0062] In this embodiment, the specific type of coal-fired unit is not limited, but generally the steam turbine is composed of high-pressure cylinder, medium-pressure cylinder and low-pressure cylinder. The unit can be a single reheat unit or a double reheat unit, combined with Figure 4 As shown, this embodiment takes the reheat unit as an example, and reheat steam is introduced. The heat storage medium used in the solar steam generation system is a binary or ternary nitrate mixture, which can meet the stable heat absorption and release process of 200-500℃.

[0063] Combine Figure 4 As shown, the thermal oil in the solar steam generation system flows sequentially through the hot section, evaporation section, and preheating section, while the feedwater flows through the preheating section, evaporation section, and superheating section, forming a thermal oil circuit, achieving countercurrent heat exchange. The feedwater valve inlet in the solar steam generation system is connected to the bypass of the designated low-temperature heater in the coal-fired unit. The pressure difference between this point and the low-pressure cylinder inlet is relatively low. This prevents excessive pressure when drawing water after the deaerator in actual use, which could lead to a large pressure difference after mixing with the exhaust steam from the intermediate-pressure cylinder and cause energy loss.

[0064] One-way valves are installed at the outlet of the equalizing tank in the solar steam generation system and at the exhaust point of the medium-pressure cylinder of the coal-fired unit into the low-pressure cylinder, allowing only steam to enter the low-pressure cylinder to avoid reverse flow of steam caused by pressure mismatch on both sides.

[0065] In this embodiment, before the solar steam generation system is started, the pressure of the thermal oil circuit is stabilized by the expansion tank so that the pressure at the input end of the thermal fluid pump is constant.

[0066] Specifically, step S110 includes: opening the water supply valve and thermal oil circuit of the solar steam generation system, introducing water supply from the low-temperature heater bypass of the coal-fired unit, and performing countercurrent heat exchange through the preheating section, evaporation section and superheating section.

[0067] In combination with the first aspect, step S120 includes:

[0068] S121, when solar radiation increases and the load of the coal-fired unit decreases, the excess solar heat is converted into sensible heat or latent heat of the heat storage medium through the heat storage heat exchanger for storage.

[0069] When solar irradiation increases, the heat generated by the solar steam generation system may exceed the current demand of the coal-fired unit. At the same time, if the coal-fired unit is in a deep peak-shaving condition (i.e., the load is low), the excess solar heat needs to be stored for subsequent use. The excess solar heat is converted into sensible heat or latent heat of the heat storage medium through a heat storage heat exchanger for storage. The heat storage medium (such as water or thermal oil) is directly heated to increase its temperature, and a phase change material (such as molten salt) is used to absorb heat and undergo a phase change (such as solid to liquid), thereby storing more energy. In this way, the waste of excess heat can be avoided and backup energy can be provided for subsequent low irradiation or high load conditions.

[0070] S122, when the solar radiation weakens and the load of the coal-fired unit recovers, the heat of the heat storage medium is released through the heat storage heat exchanger to maintain the temperature of the thermal oil.

[0071] When solar radiation weakens, the solar steam generation system's heat supply is insufficient. Meanwhile, if the coal-fired unit load increases, additional heat is required to maintain stable thermal oil temperature and low-pressure cylinder load. The heat storage medium is released through a thermal heat exchanger and transferred to the thermal oil circuit to maintain the oil temperature. The thermal storage medium releases sensible or latent heat, ensuring a stable oil temperature and thus the normal operation of the solar steam generation system. This provides a stable heat supply during periods of insufficient solar radiation, reduces the compensation load on the coal-fired units, and further reduces fuel consumption and emissions.

[0072] Combine Figure 4 As shown, the thermal storage system includes a high-temperature heat storage tank and a low-temperature contact heat tank. In this embodiment, by dynamically controlling the heat storage system's charging and discharging processes, this method effectively balances the conflict between solar energy fluctuations and coal-fired unit load variations, improving the system's flexibility, economy, and environmental performance. This not only reduces coal consumption but also improves overall energy efficiency.

[0073] The concentrators used in the solar steam generation system's heat collection device are parabolic trough or Fresnel concentrators, which heat the thermal oil to above 400°C before entering the superheating section for heat exchange. It's worth noting that tower or dish-type concentrators are not recommended because they have high concentration temperatures and don't meet the temperature matching principle. In this embodiment, the solar steam generation system is equipped with an automatic tracking system that tracks the sun's real-time position and adjusts the concentrator angle to improve concentration efficiency.

[0074] In combination with the first aspect, the solar steam generation system further includes a concentrator, and the method includes:

[0075] S210: Obtain current solar radiation intensity.

[0076] S220, when the current solar radiation intensity reaches a first preset threshold, driving the concentrating mirror to concentrate light, and driving the heat transfer oil to flow in the heat collection device, so as to increase the temperature of the heat transfer oil through concentrated heating.

[0077] S230, after the current solar radiation intensity meets the heat loss, start the circulation pump in the solar steam generation system to introduce all the heated thermal oil into the heat storage heat exchanger, perform heat exchange with the heat storage medium, and store the heat in the high-temperature heat storage tank.

[0078] First, use radiation sensors or meteorological equipment to track the real-time position of the sun to obtain current solar irradiance data.

[0079] The first preset threshold is the minimum irradiance required to cover the heat loss of the thermal oil as it flows through the pipeline from the heat collector to the energy storage system. When the solar irradiance reaches the first preset threshold, indicating sufficient solar resources, the concentrators are activated to improve heat collection efficiency. At this point, the concentrators are rotated and angled to maximize solar radiation reception, focusing sunlight onto the thermal oil pipeline within the heat collector, heating the thermal oil. This significantly improves heat collection efficiency through concentrating technology, reducing energy losses and enhancing system economics.

[0080] When the current solar radiation intensity meets the heat loss requirement, indicating that the system has collected enough heat, the circulation pump can be activated for heat exchange and heat storage. At this time, the circulation pump in the solar steam generation system is activated to direct all the heated thermal oil to the thermal storage heat exchanger. In the thermal storage heat exchanger, the thermal oil exchanges heat with the heat storage medium (such as molten salt or thermal oil), and the heat is stored in the high-temperature heat storage tank.

[0081] In this embodiment, the drive assembly used to rotate the concentrating mirror is a common structure in the prior art and will not be described in detail here. In this application, by introducing the concentrating mirror and dynamically controlling its rotation, this method further improves solar energy collection efficiency. Furthermore, through the circulation pump and thermal storage heat exchanger, effective heat storage and release are achieved, thereby balancing the conflict between solar energy fluctuations and coal-fired unit load changes, improving the system's flexibility, cost-effectiveness, and environmental performance.

[0082] In combination with the first aspect, after step S210, the method further includes:

[0083] S211, calculating the solar radiation enhancement rate based on the current solar radiation intensity and the previous solar radiation intensity.

[0084] S212: If the solar radiation enhancement rates for the first number of consecutive times are all greater than the preset rate threshold, increase the rotation speed of the heat transfer fluid pump to increase the heat collection amount of the heat collection device, thereby increasing the heat storage amount of the high-temperature heat storage tank.

[0085] By monitoring the current solar irradiance and the change in the previous solar irradiance, the rate of increase in solar irradiance can be calculated. This data helps determine whether solar resources are sufficient and whether the operating status of coal-fired units needs to be adjusted.

[0086] If the solar radiation increase rate exceeds a preset rate threshold for a first number of consecutive times (e.g., three or five times), it indicates that the solar energy resource is rapidly increasing. In this case, the speed of the thermal fluid pump can be increased to increase the amount of heat collected by the thermal collector, thereby increasing the amount of heat stored in the high-temperature thermal storage tank and fully utilizing the solar energy resource.

[0087] In this application, by introducing the calculation of the solar radiation enhancement rate and the dynamic adjustment of the coal-fired unit load, this method further improves the intelligence level and energy utilization efficiency of the system. When solar energy resources are sufficient, first, by increasing the speed of the heat transfer fluid pump when the solar radiation intensity increases rapidly, the working efficiency of the heat collection device can be effectively enhanced, thereby capturing more solar energy and increasing the amount of heat collected; secondly, as the amount of heat collected increases, the high-temperature heat storage tank is able to store more heat, providing sufficient energy reserves for subsequent use, especially when solar radiation weakens or at night, to ensure the continuous and stable operation of the system; thirdly, this strategy reduces the system's dependence on traditional energy sources such as coal-fired units, which helps achieve energy conservation and emission reduction goals; finally, this method has strong adaptability and can flexibly adjust the working state of the heat transfer fluid pump according to changes in solar radiation intensity, ensuring the efficient operation of the system under different weather conditions.

[0088] In combination with the first aspect, the method further includes:

[0089] S150, if the coal-fired unit receives a load reduction instruction, it is triggered to enter a deep peak load regulation state;

[0090] S160: When the load deviation of the coal-fired unit and the load when the coal-fired unit enters the deep peak regulation condition is less than the threshold, the water supply valve and the branch valve are switched from the closed state to the open state, so that part of the heat transfer oil is diverted to the superheating section and the evaporation section, and at the same time, part of the water is introduced into the low-temperature heater bypass.

[0091] S214, gradually increase the opening and closing angles of the water supply valve and the branch valve until the heat collected by the heat collection device is completely transferred to the water supply led out of the low-temperature heater bypass and enters the low-pressure cylinder.

[0092] When power consumption on the associated power grid surges, a load reduction instruction is sent to the coal-fired unit. This triggers a preset mechanism, controlling the coal-fired unit to enter deep peak-shaving conditions. At this point, the actual load of the coal-fired unit is obtained. When the deviation between the actual load of the coal-fired unit and the set load for deep peak-shaving conditions is less than a preset threshold, it indicates that the coal-fired unit has entered a stable deep peak-shaving state. At this point, the operating mode of the thermal oil and water supply systems can be switched to further optimize heat utilization. Specifically, the water supply valve and branch valve are switched from closed to open, partially diverting the thermal oil to the superheating and evaporation sections to ensure that the heat collected by the collector is fully utilized. At the same time, the low-temperature heater is bypassed to introduce some condensation water to prepare for subsequent heat transfer. By optimizing the operating mode of the thermal oil and water supply systems, energy losses are minimized and system efficiency is improved.

[0093] Subsequently, to ensure that the heat collected by the thermal collector is fully transferred to the feedwater from the low-temperature heater bypass and into the low-pressure cylinder, the opening and closing angles of the feedwater valve and branch valves are gradually adjusted until the heat collected by the thermal collector is fully transferred to the feedwater from the low-temperature heater bypass and smoothly enters the low-pressure cylinder. By dynamically adjusting the valve opening and closing angles, the heat transfer process is smooth and efficient, avoiding energy waste or system instability caused by excessive or insufficient valve opening and closing.

[0094] In this application, by switching the operating modes of the thermal oil and water supply systems when the load deviation of the coal-fired unit is less than a threshold and gradually adjusting the valve opening and closing angles, this method further improves heat utilization efficiency and system stability. This not only reduces coal consumption but also significantly improves the overall energy structure and system performance, achieving the coordinated optimization of coal and solar energy operation.

[0095] After step S210, the method further includes:

[0096] S2100, when the current solar radiation intensity is less than a second preset threshold, driving the concentrating mirror to stop rotating and gradually reducing the speed of the thermal fluid pump to gradually stop the flow of the thermal fluid in the heat collecting device;

[0097] At the same time, the circulation pump driving the high-temperature heat storage tank and the low-temperature heat storage tank is turned on to drive the heat storage cutoff to flow through the heat storage heat exchanger for heat exchange;

[0098] The second preset threshold is smaller than the first preset threshold.

[0099] In the present application, the second preset threshold is the minimum radiation intensity required to maintain heat loss of the heat transfer oil in the pipeline from the heat collection device to the energy storage system.

[0100] When the current solar radiation intensity is lower than the second preset threshold, it indicates that the solar energy resources are insufficient and the thermal oil cannot be effectively heated. At this time, it is necessary to stop the rotation of the concentrator and reduce the speed of the thermal fluid pump to reduce energy loss. At the same time, in order to make up for the heat gap caused by insufficient solar energy resources, it is necessary to use the stored heat in the heat storage tank to compensate. This application effectively responds to solar energy fluctuations by stopping the rotation of the concentrator, reducing the speed of the thermal fluid pump, and turning on the heat storage tank circulation pump for heat exchange when the solar radiation is insufficient. This not only reduces energy waste, but also improves the flexibility and reliability of the system, and further optimizes the synergistic operation effect of coal and solar energy.

[0101] In combination with the first aspect, after step S211, the method further includes:

[0102] S2111: If the solar radiation enhancement rate for a second number of times in a row is less than a preset rate threshold, reduce the rotation speed of the heat transfer fluid pump to reduce the amount of heat collected by the heat collecting device, thereby reducing the amount of heat stored in the high-temperature heat storage tank.

[0103] If the solar radiation increase rate is less than the preset threshold for a second consecutive time (e.g., three or five times), it indicates that the growth rate of solar energy resources has slowed or stopped. At this point, by reducing the speed of the thermal fluid pump, the heat collected by the collector and the heat stored in the high-temperature heat storage tank can be reduced. This adjustment not only avoids excessive energy consumption but also allows for the rational allocation and utilization of existing heat reserves when solar energy resources are insufficient, thereby improving the economy and stability of the entire system.

[0104] By introducing a mechanism to determine the rate of solar radiation increase after a second consecutive period and to increase the load of coal-fired units, the system's intelligence and stability are further enhanced. When solar resource growth slows or stops, the system proactively reduces heat collection and output to avoid unnecessary energy waste when solar radiation weakens. This enables refined solar energy management and further enhances the system's adaptability and operational efficiency.

[0105] In combination with the first aspect, the method further includes:

[0106] S150, when the irradiation is insufficient, close the thermal oil valves of the superheating section, evaporation section and preheating section, and start the circulation pumps of the high-temperature heat storage tank and the low-temperature heat storage tank to release the stored heat to heat the thermal oil.

[0107] S160, when there is excess radiation, the excess heat is stored in a high-temperature heat storage tank through a heat storage heat exchanger.

[0108] In this embodiment, when solar radiation is insufficient (such as at night or on cloudy days), the heat supply of the solar steam generation system may not be able to meet the needs of the coal-fired unit. In this case, an additional heat source is required to maintain the thermal oil temperature and low-pressure cylinder load stability. At this time, the thermal oil valves in the superheating section, evaporation section, and preheating section are closed, and the circulation pumps of the high-temperature heat storage tank and the low-temperature heat storage tank are started to release the stored heat. The heat in the high-temperature heat storage tank is transferred to the low-temperature heat storage tank through the circulation pump, while also heating the thermal oil circuit. In this way, a stable heat supplement is provided when solar radiation is insufficient, reducing the compensation load of the coal-fired unit, and further reducing fuel consumption and emission pollution.

[0109] When solar radiation is excessive (such as during midday on a sunny day), the heat generated by the solar steam generation system may exceed the current demand of the coal-fired units. In these cases, the excess heat needs to be stored for later use. This excess heat is then transferred to a high-temperature thermal storage tank via a thermal storage heat exchanger. The thermal storage heat exchanger then transfers heat from the thermal oil circuit to the thermal storage medium (such as molten salt or thermal oil) in the high-temperature thermal storage tank. This prevents excess heat from being wasted and provides backup energy for subsequent low-irradiance or high-load conditions.

[0110] In this embodiment, the dynamic control of the heat storage system's charge and discharge processes balances the conflict between solar energy fluctuations and coal-fired unit load variations, improving the system's flexibility, economy, and environmental performance. This not only reduces coal consumption but also improves overall energy efficiency.

[0111] In the second aspect, the present application provides a device for improving the economy of low-load steam turbines, combined with Figure 2 As shown, the device includes: a generating module 10 , a controlling module 20 , a mixing module 30 , and an adjusting module 40 .

[0112] The generation module is used to open the water supply valve and thermal oil circuit of the solar steam generation system when the coal-fired unit enters the deep peak-shaving operation mode, introduce water supply from the low-temperature heater bypass of the coal-fired unit, and perform countercurrent heat exchange through the preheating section, evaporation section and superheating section to generate superheated steam.

[0113] The control module is used to dynamically control the heat storage system in the solar steam generation system based on the solar radiation intensity and the load changes of the coal-fired unit.

[0114] The mixing module is used to introduce the superheated steam generated by the solar steam generation system into the equalizing tank and mix it with the exhaust steam from the intermediate pressure cylinder of the coal-fired unit. The pressure of the mixed steam is adjusted through the equalizing tank to match the inlet pressure of the low-pressure cylinder.

[0115] The adjustment module is used to adjust the feedwater valve opening and thermal oil flow according to the load changes of the unit, so that the solar steam supplement amount can adapt to the demand of the low-pressure cylinder and maintain the low-pressure cylinder load in the high-efficiency range.

[0116] In a third aspect, the present application provides an electronic device, Figure 3 As shown, the electronic device includes a memory 131 and a processor 130. The memory 131 is used to store computer programs, and the processor 130 runs the computer programs to enable the electronic device to perform the above method.

[0117] Further, combined with Figure 3 The electronic device shown further includes a bus 132 and a communication interface 133 , and the processor 130 , the communication interface 133 and the memory 131 are connected via the bus 132 .

[0118] The memory 131 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk storage. The communication connection between the system network element and at least one other network element is achieved through at least one communication interface 133 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used. The bus 132 may be an ISA bus, a PCI bus, or an EISA bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0119] The processor 130 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in the processor 130 or by software instructions. The processor 130 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of the present invention can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in memory 131, and processor 130 reads information in memory 131 and, in conjunction with its hardware, completes the steps of the method of the aforementioned embodiment.

[0120] In a fourth aspect, an embodiment of the present application provides a readable storage medium, in which computer program instructions are stored. When the computer program instructions are read and executed by a processor, the above-mentioned method is executed.

[0121] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems and devices can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0122] In addition, in the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0123] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0124] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0125] Finally, it should be noted that the above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for improving the economic efficiency of a low-load steam turbine, characterized in that: The method is applied to a coupled system comprising a solar steam generation system and a coal-fired unit, wherein a feedwater valve inlet in the solar steam generation system is connected to a bypass of a designated low-temperature heater in the coal-fired unit; the method comprises: When the coal-fired unit enters a deep peak-shaving operating condition, the solar steam generation system is turned on to generate superheated steam; Dynamically controlling the heat storage system in the solar steam generation system based on solar radiation intensity and load changes of the coal-fired unit; The superheated steam generated by the solar steam generation system is introduced into a pressure equalizing tank and mixed with the exhaust steam of the intermediate pressure cylinder in the coal-fired unit to adjust the mixed steam pressure and match the inlet pressure of the low pressure cylinder in the coal-fired unit; According to the load change of the coal-fired unit, the water supply valve opening and the thermal oil flow rate are adjusted to make the solar steam supplement amount adapt to the demand of the low-pressure cylinder and maintain the load of the low-pressure cylinder in the high-efficiency range.

2. The method according to claim 1, characterized in that The step of dynamically controlling the heat storage system in the solar steam generation system based on the solar radiation intensity and the load change of the coal-fired unit includes: When solar radiation increases and the load of the coal-fired unit decreases, excess solar heat is converted into sensible heat or latent heat of a heat storage medium through a heat storage heat exchanger for storage; When the solar radiation weakens and the load of the coal-fired unit recovers, the heat of the heat storage medium is released through the heat storage heat exchanger to maintain the temperature of the thermal oil.

3. The method according to claim 1, characterized in that The solar steam generation system further includes a concentrator, and the method includes: Get the current solar radiation intensity; If the current solar radiation intensity reaches a first preset threshold, the concentrating mirror is driven to concentrate light, and the heat transfer oil is driven to flow in the heat collection device, so that the heat transfer oil is heated by concentrated heating; After the current solar radiation intensity meets the heat dissipation loss, the circulation pump in the solar steam generation system is started to introduce all the heated thermal oil into the heat storage heat exchanger, perform heat exchange with the heat storage medium, and store the heat in the high-temperature heat storage tank.

4. The method according to claim 3, characterized in that After obtaining the current solar radiation intensity, the following steps are also included: Calculating a solar radiation increase rate based on the current solar radiation intensity and the previous solar radiation intensity; If the solar radiation enhancement rates for a first number of times in a row are all greater than a preset rate threshold, the rotation speed of the heat transfer fluid pump is increased to increase the amount of heat collected by the heat collecting device, thereby increasing the amount of heat stored in the high-temperature heat storage tank.

5. The method according to claim 4, characterized in that The method further comprises: If the coal-fired unit receives a load reduction instruction, it is triggered to enter a deep peak load regulation state; When the load deviation of the coal-fired unit and the load of the coal-fired unit entering the deep peak load regulation condition is less than a threshold value, the water supply valve and the branch valve are switched from a closed state to an open state, so that part of the thermal oil is diverted to the superheating section and the evaporation section, and at the same time, part of the water is introduced into the low-temperature heater bypass; Gradually increase the opening and closing angles of the water supply valve and the branch valve until the heat collected by the heat collection device is completely transferred to the accumulated water led out of the low-temperature heater bypass and then into the low-pressure cylinder.

6. The method according to claim 3, characterized in that After obtaining the current solar radiation intensity, the following steps are also included: If the current solar radiation intensity is less than a second preset threshold, the concentrating mirror is driven to stop rotating, and the speed of the thermal fluid pump is gradually reduced to gradually stop the flow of the thermal oil in the heat collecting device; At the same time, the circulation pump driving the high-temperature heat storage tank and the low-temperature heat storage tank is turned on to drive the heat storage cutoff to flow through the heat storage heat exchanger to perform heat exchange; The second preset threshold is smaller than the first preset threshold.

7. The method according to claim 4, characterized in that After the step of calculating the solar radiation increase rate based on the current solar radiation intensity and the previous solar radiation intensity, the method further includes: If the solar radiation enhancement rate is less than the preset rate threshold for a second number of times in a row, the rotation speed of the thermal fluid pump is reduced to reduce the amount of heat collected by the heat collecting device, thereby reducing the amount of heat stored in the high-temperature heat storage tank.

8. A device for improving the economic efficiency of a low-load steam turbine, characterized in that: The device is applied to a coupled system comprising a solar steam generation system and a coal-fired unit, wherein the feedwater valve inlet of the solar steam generation system is connected to a bypass of a designated low-temperature heater in the coal-fired unit; the device comprises: A generation module, configured to activate the solar steam generation system to generate superheated steam when the coal-fired unit enters a deep peak-shaving operating condition; a control module for dynamically controlling the heat storage system in the solar steam generation system based on solar radiation intensity and load changes of the coal-fired unit; A mixing module is used to introduce the superheated steam generated by the solar steam generation system into the pressure equalizing tank and mix it with the exhaust steam of the intermediate pressure cylinder in the coal-fired unit to adjust the mixed steam pressure and match the inlet pressure of the low pressure cylinder in the coal-fired unit; The adjustment module is used to adjust the water supply valve opening and the thermal oil flow rate according to the load change of the coal-fired unit, so that the solar steam supplement amount can adapt to the demand of the low-pressure cylinder and maintain the load of the low-pressure cylinder in the high-efficiency range.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to perform the method according to any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium stores computer program instructions, and when the computer program instructions are read and executed by a processor, the method according to any one of claims 1 to 7 is executed.

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