A coal-fired power plant water-heat-chemical value-added system for a new power system and an intelligent flexible operation method thereof

Abstract

The application discloses a coal-fired power plant water-heat-chemical value-added system for a new power system and an intelligent flexible operation method thereof. The system comprises a coal-fired generator unit, a heat-steam-power coupling subsystem, a water-hydrogen-oxygen coupling subsystem and a carbon-chemical coupling subsystem integrated with the coal-fired generator unit, and is uniformly coordinated by an intelligent collaborative control unit. Solid particle storage flue gas waste heat can be used to quickly produce steam injection into a steam turbine to improve the frequency modulation response speed of the unit. Low-valley electricity is used to electrolyze hydrogen, and by-product oxygen is recycled. Hydrogen and captured carbon dioxide are used to synthesize green methanol to realize carbon resource utilization. Methanol synthesis reaction heat and electrolysis waste heat are recovered in stages. The operation method can intelligently switch and cooperate between fast frequency modulation, hydrogen production by electrolysis and methanol synthesis according to grid instructions and real-time electricity prices, so that the flexibility of the unit, resource utilization and comprehensive benefits are systematically improved.

Description

Technical Field

[0001] This invention belongs to the field of power plant water treatment technology, specifically relating to a water-heat-chemical value-added system for coal-fired power plants for new power systems and its intelligent and flexible operation method. Background Technology

[0002] In the process of building a new power system dominated by new energy sources, thermal power generation, especially coal-fired units, is undergoing a fundamental transformation from providing stable base load electricity to providing flexible regulation services. With the continuous increase in the installed capacity and power generation share of intermittent renewable energy sources such as wind power and photovoltaics, the demand for flexible resources in the power system is becoming increasingly urgent, requiring coal-fired units to have faster load response speeds, deeper peak-shaving capabilities, and better low-load operating economics. However, there is a profound contradiction between the traditional design and operation mode of coal-fired units and this new demand. Existing technological transformation solutions are mostly localized optimizations and fail to provide fundamental solutions from the perspective of system integration and material-energy synergy, mainly exhibiting the following three significant limitations:

[0003] First, in terms of speed and flexibility, the rapid adjustment capability of coal-fired power units is limited by their inherent large thermal inertia, and existing speed-up solutions suffer from low energy efficiency and poor integration. The mechanical and thermodynamic inertia of the boiler-turbine-generator system means that its traditional load change rate is usually only 1%-2% of the rated power per minute, making it difficult to respond to grid frequency regulation and ramp-up commands on a minute or even second-level basis. Although current attempts have been made to improve the adjustment speed by using technologies such as adding electric boilers and independent thermal storage tanks, these systems often have low coupling with the main unit's thermodynamic cycle. Energy needs to go through multiple "electric-to-heat" or "heat-to-heat" conversions, resulting in significant system efficiency losses. Furthermore, the generated steam is difficult to precisely match and quickly and seamlessly integrate with the original thermodynamic process of the turbine in terms of parameters (pressure, temperature), failing to fundamentally solve the core bottleneck of unit power response delay.

[0004] Secondly, in terms of operational economy and resource utilization, generating units face a dual dilemma of "decreased revenue" and "resource waste" during deep peak shaving, and the existing technological routes lack synergy. During periods of low grid load caused by the surge in renewable energy generation, coal-fired units often need to perform deep peak shaving to the minimum technical output to ensure grid balance. At this time, the on-grid electricity price is low or even negative, leading to a sharp deterioration in operational economy. At the same time, the units continue to generate a large amount of low-grade flue gas waste heat and high-quality demineralized water produced by the chemical water treatment plant even under low load conditions. These resources are largely wasted under traditional operating methods. In addition, carbon capture devices installed to fulfill low-carbon obligations have high operating energy consumption. If the carbon dioxide generated cannot be utilized as a resource, it becomes an additional operating cost burden, exacerbating the operating pressure on the power plant. Existing solutions, such as building independent hydrogen production stations to absorb surplus electricity, are usually disconnected from the power plant's existing water, heat, and carbon material flow systems, failing to achieve a closed-loop system of matter and energy. This results in low overall system energy efficiency, long project investment payback periods, and poor economic performance.

[0005] Third, regarding the safety of flexible operation, traditional control modes are ill-suited to the stringent requirements of new operating conditions. During periods of intense peak shaving and rapid load changes, the temperature, pressure, and flow parameters of the unit's water-steam system experience significant fluctuations. Traditional chemical dosing and water condition control methods, based on delayed feedback, are ill-suited to adapt to these dramatic load and condition fluctuations in real time and proactively. This can easily lead to excessive concentrations of corrosive media in thermal equipment or an increased risk of scaling, threatening the unit's long-term safe operating life and reliability.

[0006] In summary, the existing technological system is fragmented and has not yet provided a systematic solution to simultaneously overcome the three intertwined core challenges faced by coal-fired power units in new power systems: insufficient rapid response capability, poor economic efficiency and low resource utilization efficiency during off-peak hours, and increased safety risks under flexible operation. Therefore, there is an urgent need for an innovative integrated system and intelligent operation method that can deeply integrate energy and material flows, achieve cascaded utilization of thermal energy, diversified conversion of electrical energy, closed-loop carbon resource management, and ensure safe and stable operation throughout the entire process. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a water-heat-chemical value-added system for coal-fired power plants and its intelligent and flexible operation method for a new type of power system.

[0008] The specific technical solution is as follows:

[0009] A water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system includes the following components:

[0010] This system uses existing coal-fired power generating units as its core hub. Through a unique material and energy coupling pathway, it deeply integrates and innovates three major processes: sensible heat storage, water electrolysis for hydrogen production, and carbon dioxide hydrogenation for methanol synthesis, forming an intelligent integrated energy production island. The system specifically includes coal-fired power generating units, a heat-steam-power coupling subsystem, a water-hydrogen-oxygen coupling subsystem, a carbon-chemical coupling subsystem, and an intelligent collaborative control unit.

[0011] The coal-fired power generation unit includes a boiler, a steam turbine, a generator, a flue gas treatment module, a chemical water treatment module, a carbon dioxide capture device, and a boiler feedwater treatment module. This unit is the foundation of the system, providing electrical energy, thermal energy (flue gas waste heat), material resources (demineralized water, CO2), and receiving regulation commands.

[0012] The flue gas treatment module includes a denitrification reactor, a dust collector, and a desulfurization tower connected in sequence. The flue gas discharged from the boiler is treated by the flue gas treatment module before being discharged.

[0013] The chemical water treatment module includes a condensate treatment unit and a raw water treatment unit. The condensate treatment unit includes a condenser, a cooling tower, and a condensate polishing device. The water from the steam turbine is condensed by the condenser and then polished to serve as boiler feedwater. The raw water treatment unit includes a pretreatment device, a raw water heater, a pre-desalination device, and a deep desalination device. After coagulation and filtration in the pretreatment device, most of the raw water (river water, groundwater, seawater, etc.) enters the raw water heater for heating, while a small portion is heated by hydrogen production through water electrolysis. The heated warm raw water enters the pre-desalination device for ultrafiltration / reverse osmosis, and then enters the deep desalination device (ion exchange / EDI) to obtain demineralized water, which serves as the source of electrolyzed water and boiler feedwater.

[0014] The boiler feedwater treatment module includes a low-pressure heater, a deaerator, and a high-pressure heater. Some of the boiler feedwater directly enters the low-pressure collector for treatment before entering the deaerator and high-pressure heater. Some of the feedwater enters the carbonization coupling subsystem for heating before entering the deaerator and high-pressure heater. After heating, it is used as boiler feedwater and steam generator feedwater.

[0015] The core of the aforementioned heat-steam-power coupling subsystem is the storage of sensible heat from solid particles and rapid steam generation, which is deeply embedded in the unit's thermal system to solve the problem of rapid load changes. This unit consists of a solid particle sensible heat storage and release device and a steam generator, used to utilize waste heat from flue gas to store sensible heat and rapidly generate steam to inject into the turbine, thereby increasing the power generation capacity of the coal-fired generator unit.

[0016] The solid particle sensible heat storage and release device includes a flue gas-particle fluidized bed heat exchanger, a low-temperature particle storage tank (operating temperature 100℃), and a high-temperature particle storage tank (operating temperature 450℃).

[0017] The flue gas-particle fluidized bed heat exchanger has its flue gas side inlet connected to the flue between the economizer and the air preheater;

[0018] The low-temperature particle storage tank is connected to the particle inlet of the flue gas-particle fluidized bed heat exchanger, and the high-temperature particle storage tank is connected to the particle outlet of the flue gas-particle fluidized bed heat exchanger.

[0019] The steam generator is a downward moving bed type steam generator. Its particle inlet is connected to a high-temperature particle storage tank, its feedwater inlet is connected to the boiler feedwater treatment module, and its steam outlet is connected to the steam turbine through a pipeline.

[0020] The heat storage medium is made of high-alumina bauxite ceramic particles with a particle size of 0.5-1.0 mm and a bulk density of about 1800 kg / m³.

[0021] A certain proportion (approximately 3-5%) of flue gas is extracted from the flue gas duct (between the economizer and air preheater) at approximately 400-500°C and directly used to heat solid particles, achieving efficient recovery of flue gas waste heat. To achieve second-level steam generation response, this invention designs a downward moving bed steam generator, whose feedwater inlet is directly connected to the outlet header of the high-pressure heater of the power plant boiler, using feedwater at approximately 280°C. High-temperature particles flow slowly downwards under gravity, undergoing efficient counter-current heat transfer with the upward-flowing feedwater on the heat exchange tube wall, continuously and stably generating saturated steam or slightly superheated steam at 1.0-1.5 MPa for 60-90 seconds. The generated steam is collected through the steam header at the top of the generator, and after passing through an electric isolation valve and a pressure regulating valve, is injected into the connecting pipe between the intermediate-pressure cylinder and the low-pressure cylinder of the turbine or into the low-pressure cylinder inlet through a newly added pipeline. This immediate replenishment of steam directly increases the turbine's flow rate, thereby enabling a rapid and precise increase in the unit's power generation capacity before significant adjustments are made to the boiler's main combustion, thus solving the inherent response delay problem of coal-fired units.

[0022] The water-hydrogen-oxygen material circulation coupling subsystem is connected to the plant power module for power supply, the chemical water treatment module of the coal-fired generator set, the flue gas treatment module, and the boiler. It includes an electrolytic hydrogen production device and a second heat exchanger, which is used to electrolyze the water source treated by the chemical water treatment module to produce hydrogen and oxygen. The oxygen is recycled for enriched combustion in the boiler and / or flue gas desulfurization. The hydrogen is transported to the carbon-chemical coupling subsystem and used as the raw material gas for methanol synthesis. The waste heat of the electrolytic hydrogen production device is used to preheat the raw water through the second heat exchanger.

[0023] The core function of this system is to utilize inexpensive electricity during low-load periods to drive the electrolysis of water to produce hydrogen and oxygen, thereby achieving energy transfer and added value of material resources. This subsystem includes water, electrical, and gas circuits. In winter, under low-temperature conditions, to ensure the output and desalination rate of the pre-desalination system (ultrafiltration-reverse osmosis), a high-grade heat source (such as steam) is usually required to preheat the pretreated water via a heat exchanger. In this invention, the cold raw water produced from the raw water pretreatment is led out through an additional independent pipeline. The cold raw water is preheated using the low-temperature waste heat released by the water electrolysis hydrogen production unit, reaching a temperature of 30°C, and then directly transported to the raw water tank of the pre-desalination unit (ultrafiltration-reverse osmosis) for desalination. This design eliminates the need for independent water treatment facilities, reduces the consumption of high-grade heat sources, effectively utilizes low-temperature waste heat, and significantly reduces system operating costs.

[0024] The circuit connections reflect the system's responsiveness to the electricity market. The power input of the electrolysis hydrogen production unit is directly connected to the low-voltage side of the main transformer or to the busbars of the wind power and photovoltaic power generation systems within the plant via the plant's auxiliary power module. The intelligent collaborative control unit receives real-time electricity spot market price signals. When it determines that the current or predicted future period is a low-demand period and the electricity price is below a set threshold, it immediately issues an instruction. This instruction, on the one hand, appropriately reduces the generator load to the lower limit of technical tolerance, and on the other hand, starts and gradually increases the DC operating power of the electrolyzer, converting surplus electricity during off-peak hours—which would otherwise be difficult to connect to the grid or have poor economic viability—into the chemical energy of hydrogen.

[0025] The gas path completes the separation and resource utilization of the products. The high-purity hydrogen (>99.99%) generated on the cathode side of the electrolyzer is cooled, dried, and pressurized before entering a hydrogen storage tank array for buffer storage. Its downstream outlet is divided into two paths: one connects to the methanol synthesis unit as feed gas; the other can be connected to a planned hydrogen refueling station or external sales pipeline. In addition, the high-purity oxygen (>99.5%) generated simultaneously on the anode side of the electrolyzer is not discharged but is collected, pressurized, and then returned to the power plant's internal energy system through a dedicated pipeline. Specifically, one path of oxygen is led to the boiler primary air fan outlet duct, where it is mixed with combustion air at a certain ratio (usually not exceeding 3%, the specific ratio is determined by combustion optimization model calculation based on boiler combustion design and real-time operating conditions) through a precisely controlled mixing device to achieve oxygen-enriched combustion and improve boiler efficiency; the other path can be connected to the oxidation fan inlet of the flue gas desulfurization tower to enhance the oxidation rate of calcium sulfite in the desulfurization slurry, improve desulfurization efficiency, and reduce plant power consumption. Thus, this subsystem not only achieves low-cost conversion of electrical energy into hydrogen energy, but also uses the by-product oxygen as a process enhancer to feed back into the main system, forming a full-element cycle and synergistic effect of "water-hydrogen-oxygen".

[0026] The core of the carbon-chemical coupling subsystem is to convert the product of the carbon dioxide capture unit and hydrogen produced by water electrolysis into green methanol through a catalytic synthesis process. This subsystem mainly consists of three functional units: feedstock gas supply and pretreatment, methanol synthesis reaction, and product separation and purification, integrated into the overall framework of the power plant through a specific process route and connection method. In the feedstock gas supply and pretreatment unit, liquid carbon dioxide from the power plant's low-partial-pressure carbon capture system first enters a carbon dioxide buffer storage tank located near the capture unit. After being vaporized by an electrically heated vaporizer, it enters the feedstock gas compressor section for initial pressurization. Simultaneously, hydrogen from the electrolysis hydrogen production unit, after drying and purification, is pressurized to a pressure matching that of the carbon dioxide through a hydrogen treatment unit. The two gas streams are initially mixed in a static mixer at a hydrogen-to-carbon molar ratio of approximately 2.8:1 to 3.0:1. Subsequently, the mixed gas enters a two-stage compression and purification system, typically installed in the water treatment workshop or a separate auxiliary equipment room. First, the pressure is increased to the 5.0–8.0 MPa required for methanol synthesis (medium-pressure method). Then, it passes sequentially through a fine desulfurization tank containing zinc oxide desulfurizer and activated carbon adsorbent to remove the total sulfur content to below 0.1 ppm, preventing subsequent catalyst poisoning. The purified syngas is then preheated to approximately 220°C after recovering heat from the reactor outlet in a syngas preheater.

[0027] Specifically, it includes a methanol synthesis reactor and a first heat exchanger. The hydrogen outlet of the electrolytic hydrogen production unit and the carbon dioxide capture unit outlet are respectively connected to the methanol synthesis reactor. The methanol synthesis reactor is connected to the first heat exchanger, and the first heat exchanger is connected to the boiler feedwater treatment module.

[0028] The methanol synthesis reactor is the core of this subsystem, employing a shell-and-tube isothermal reactor located on a steel-framed platform outside the boiler room. The reactor tubes are filled with a copper-based catalyst, composed of CuO / ZnO / Al₂O₃, with small amounts of additives added depending on the water quality. The shell side serves as the heating channel for boiler feedwater, coupled with the thermal system (feedwater at 90-110°C from the low-pressure heater outlet flows through the shell to absorb reaction heat, raising its temperature to 180-200°C before being injected into the deaerator). Preheated synthesis gas enters the catalyst bed from the top of the reactor, where a synthesis reaction occurs under pressure of 5.0-8.0 MPa, temperature of 220-250°C, and the action of the catalyst to produce methanol. The heat released by this strongly exothermic reaction is promptly removed by the boiler feedwater flowing outside the tubes, thus maintaining a stable bed temperature. This design ensures both reaction efficiency and simultaneous recovery of reaction heat. The reactor outlet gas is a mixture containing methanol, water vapor, unreacted hydrogen, and carbon dioxide.

[0029] The core of designing the above three subsystems lies in constructing a three-stage heat recovery network that is matched with the process depth and utilized in stages according to grade, realizing closed-loop optimization of heat flow and engineering improvement of unit flexibility.

[0030] The first-stage recovery (medium-high temperature flue gas waste heat storage, heat source temperature 400~500℃) is the energy foundation for this system's rapid peak-shaving capability. The specific implementation path is as follows: an exhaust port is opened on the side wall of the vertical flue between the boiler economizer outlet and the air preheater inlet (where the flue gas temperature is stable within the 400~500℃ range), and a pneumatic high-temperature flue gas regulating butterfly valve is installed. From this, a steel flue insulated with aluminosilicate refractory fiber is led out, connecting to a modularly designed flue gas-solid particle fluidized bed heat exchanger. This vertical fluidized bed heat exchanger has a wind-cap type air distribution plate at the bottom. Ceramic particles from the low-temperature particle storage tank (approximately 80~100℃) are continuously added from the top through a sealed rotary feed valve, where they are fully fluidized and mixed by the 400~500℃ hot flue gas fed from the bottom, achieving efficient heat exchange. After the particles are heated to the design target temperature of 400-450℃, they enter the medium-temperature particle storage tank (a vertical steel tank with a refractory lining, the capacity of which is designed according to peak-shaving requirements) through the overflow pipe at the bottom of the heat exchanger, completing the sensible heat storage. The flue gas, cooled to approximately 200-250℃, is then sent back to the original flue gas duct before the air preheater inlet by a high-temperature induced draft fan, ensuring that it does not affect subsequent environmental protection processes such as denitrification and dust removal. This stage of recovery converts the waste heat of the medium-temperature flue gas in the power plant into directly dispatchable solid thermal energy, which is key to achieving minute-level power response.

[0031] The second-stage recovery (direct reuse of heat from the intermediate-temperature chemical reaction, approximately 220-250℃) involves directly coupling the shell-and-tube isothermal reactor of the methanol synthesis unit with the power plant's feedwater thermal system. The methanol synthesis (exothermic reaction) reactor is used as an independent high-temperature feedwater heater, directly embedded and partially replacing the traditional turbine extraction and regenerative system. Specifically, a bypass stream is drawn from the feedwater pipeline located at the outlet of the #1 low-pressure heater (approximately 90-110℃). Controlled by a high-temperature booster pump and flow regulating valve, this bypass stream is fed into the bottom shell side of the methanol synthesis reactor as a cooling medium. As this feedwater flows through the reactor shell, it fully absorbs the constant-temperature heat (220-250℃) continuously released by the synthesis reaction within the tubes, raising its own temperature to 180-200℃. Subsequently, the heated high-temperature feedwater is not returned to the original low-pressure heater system but is directly injected into the downstream deaerator inlet feedwater header through an insulated pipeline. This connection method allows the heat of chemical reaction in methanol synthesis to directly and stably replace the heat source that originally required steam extraction from the turbine to drive the #2 and #3 low-pressure heaters. The direct benefit is that the steam extracted from the corresponding section of the turbine can be saved and used entirely for further expansion work, thereby directly increasing the net output power of the generator and simplifying the system process. To ensure the reliability and safety of this deep coupling, a three-way regulating valve group with intelligent water flow distribution is installed at the outlet of the #1 low-pressure heater, and a strict temperature-pressure interlock protection mechanism is established to ensure that the feedwater flow can instantly switch back to the original thermal system when the main chemical process is shut down.

[0032] The third-stage recovery system (low-temperature waste heat upgrading and utilization, temperature approximately 40-60℃) targets the cooling waste heat from the proton exchange membrane electrolysis hydrogen production unit. The implementation involves installing a plate heat exchanger in parallel as a heat recovery unit within the closed-loop deionized water cooling circulation loop of the electrolyzer. The heated circulating cooling water from the electrolyzer (approximately 50-60℃) flows through this heat exchanger as the hot-side medium. On the cold side, the raw water inlet pipeline (at ambient temperature) used for demineralization in the chemical water treatment workshop is connected. Through heat exchange, the raw water is preheated by 10-15℃ to approximately 30℃ before entering the demineralization process (ultrafiltration-reverse osmosis-ion exchange / EDI). This design, through simple bypass heat exchange, significantly reduces the steam heating load of the water treatment workshop at a very low cost, achieving effective utilization of the waste heat at the very end of the system.

[0033] This three-stage thermal energy network, through precise thermodynamic design and process coupling, forms a model of "flue gas heat-driven energy storage, reaction heat reinjection for power generation, and waste heat preheating of raw materials," thereby improving the overall thermal utilization efficiency of the entire plant.

[0034] The core function of the aforementioned intelligent collaborative control unit is to integrate the previously independent hardware devices, such as coal-fired power generation, pellet thermal storage, electrolytic hydrogen production, and methanol synthesis, into a unified whole capable of proactively and collaboratively responding to external commands and market signals through unified data perception, intelligent decision-making, and precise execution. This unit adopts a three-layer logical architecture of "information-optimization-execution" to achieve closed-loop control across the entire chain, from global optimization to equipment actions.

[0035] At the information perception and fusion layer, the control unit collects and integrates four types of key data in real time through the industrial network. The first type is external commands, including automatic generation control commands and active power setpoints from the power grid dispatching agency. The second type is electricity market signals, including real-time node electricity prices in the electricity spot market. The third type is resource and material status, mainly the demineralized water storage in the water treatment plant, the liquid carbon dioxide storage tank level in the carbon capture unit, and the finished methanol storage tank level. The fourth type is the status parameters of the main unit and core equipment, including the real-time load, main steam parameters, and key metal temperatures of the steam turbine in the coal-fired power generation unit; the high / low temperature tank levels and temperatures in the solid particle thermal energy storage unit; the DC power, hydrogen production flow rate, and hydrogen storage tank pressure in the electrolysis hydrogen production unit; and the reactor bed temperature, system pressure, and circulating gas composition in the methanol synthesis unit.

[0036] The intelligent decision-making and optimization layer is the core logic processing center of the control unit. Its core responsibility is to rapidly analyze real-time integrated operating condition and market data based on the principle of "grid safety first, economy-driven," and make judgments on the selection of operating modes accordingly. The decision-making logic of this layer is a clear sequence of conditional judgments: First, the system continuously monitors and prioritizes responses to rapid frequency regulation or emergency load commands from the grid. Once such commands are detected, the system will immediately trigger the corresponding rapid power regulation process. In the absence of urgent grid demand, the system switches to a decision-making path centered on economy. At this point, the key to the decision lies in comparing the real-time electricity price with two internally dynamically calculated economic thresholds. Based on the real-time acquired market prices of hydrogen and methanol, and the real-time efficiency and cost parameters of each energy conversion unit, the system calculates the first economic threshold (T1) and the second economic threshold (T2) online. By comparing the relative levels of the real-time electricity price and these two thresholds, and combining key states such as the hydrogen storage tank level, this layer will automatically determine which economic operating mode the system should enter, thereby completing the mapping from complex data to a clear operating strategy.

[0037] At the instruction decomposition and execution layer, the high-level strategies output by the optimization layer are translated into specific, executable sets of device-level action instructions, which are then distributed through the distributed control system and programmable logic controller (PLC). For example, when executing the "thermal storage power regulation mode," the DCS will sequentially and in a chain-like manner trigger the following actions: adjust the opening of the rotary discharge valve at the bottom of the high-temperature granular storage tank to the target value, adjust the feedwater regulating valve of the steam generator to match the target steam flow rate, and finally control the pressure regulating valve on the steam injection pipeline to ensure that the steam is smoothly integrated into the turbine thermal system. When executing the "multi-energy cogeneration mode," the control unit will coordinate the generator set to reduce its output, while simultaneously sending a power setpoint to the rectifier power supply of the electrolysis hydrogen production unit and sending start / stop or load regulation instructions to the sequential control system of the methanol synthesis unit. The execution effects of all instructions are fed back in real time through the sensor network of the information layer, forming a complete control closed loop of "perception-decision-execution-re-perception," thereby ensuring that the entire composite system can operate stably, efficiently, and safely under various complex operating conditions, realizing the intelligent transformation from traditional single power generation to integrated flexible energy supply.

[0038] In summary, this system, through the coupling of material flow (water → hydrogen / oxygen → methanol; CO2 → methanol) and energy flow (electrical energy → chemical energy; waste heat from flue gas and heat of reaction → thermal energy → work), constructs an integrated system for the co-production and synergistic regulation of multiple energy sources including electricity, heat, hydrogen, and alcohol.

[0039] Intelligent and flexible operation methods for coal-fired power units in new power systems:

[0040] The operating method provided by this invention, based on the aforementioned "water-heat-chemical value-added system for coal-fired power plants," aims to fundamentally change the operating paradigm of traditional coal-fired units, transforming them into intelligent energy units capable of proactively responding to grid demands, flexibly adjusting output, and achieving multi-energy co-production. This method, through global scheduling by an intelligent collaborative control unit, intelligently judges, seamlessly switches, and coordinates between various optimized operating modes based on real-time grid dispatch instructions, electricity market signals, and internal equipment status. This systematically resolves the contradictions of insufficient rapid adjustment capability, poor economic efficiency during off-peak periods, and low overall energy utilization efficiency of the units.

[0041] I. Rapid Frequency Regulation and Load Ramp-up Operation Mode

[0042] This mode is designed to meet the urgent needs of new power systems for rapid frequency regulation and short-term power support. When the intelligent collaborative control unit receives a rapid load increase command from the grid dispatch system (e.g., a request to increase the rated load by 20% within 10 minutes), it immediately activates the "thermal storage and power regulation" strategy. While maintaining the basic stability of the boiler's main combustion conditions, the system prioritizes instructing the solid particle sensible heat storage and rapid steam generation units to initiate a rapid heat release program. Specifically, the control unit synchronously adjusts the opening of the rotary discharge valve at the bottom of the high-temperature particle storage tank and the feedwater regulating valve of the steam generator, enabling efficient heat exchange between the high-temperature particles and the low-temperature feedwater from the condensate system in the moving bed steam generator. This allows for a continuous and stable output of qualified steam at 1.0~1.5 MPa for 60 to 90 seconds. This steam is directly injected into the connecting pipe between the low-pressure cylinders of the turbine. This immediate supplementary steam flow is instantly converted into additional power generation output, enabling the unit to independently achieve a rapid and precise increase in power generation output before significant changes in the boiler's main steam parameters. This mode can effectively increase the net ramp rate of the unit to 2 to 3 times the traditional value. It is particularly suitable for smoothing the minute-level drastic fluctuations in wind power and photovoltaic power output, as well as coping with sudden increases in regional grid load, and significantly enhances the instantaneous power balance capability of the grid.

[0043] II. Multi-energy co-production and dynamic optimization operation mode

[0044] This model aims to intelligently optimize the plant's energy flow and product structure based on dynamic changes in electricity market prices, maximizing overall operational economics. The intelligent collaborative control unit analyzes the spot electricity price curve in real time and compares it with the market prices of hydrogen and methanol. When the real-time electricity price drops to a preset first economic threshold (which comprehensively considers the marginal cost of power generation and the revenue from hydrogen production), the system automatically decides to enter a "multi-energy co-production" state. The control unit coordinates the generator units to reduce their output to the minimum safe technical output, while simultaneously directing surplus electricity to the proton exchange membrane electrolysis hydrogen production unit, increasing its DC operating power and converting low-priced electricity into high-purity hydrogen for storage, completing the conversion of electrical energy into chemical energy and its storage across time periods. Furthermore, when the electricity price falls to a lower second threshold (e.g., during deep load troughs at night or peak photovoltaic power generation during holidays), and the system assesses sufficient hydrogen reserves, the control unit will automatically trigger the start-up or load increase procedure of the carbon-chemical coupling subsystem, catalytically synthesizing the stored hydrogen with carbon dioxide captured by the power plant into green methanol. Through this dynamic, market-signal-based optimization of energy conversion paths, power plants can expand their single revenue structure from electricity supply into a diversified revenue system encompassing electricity supply revenue, frequency regulation ancillary service revenue, hydrogen sales revenue, and methanol product profits. This allows them to maintain good profitability stability and market competitiveness even during periods of low electricity prices due to high penetration of new energy sources.

[0045] The first economic threshold (T1) is the critical electricity price for starting electrolytic hydrogen production, and the suggested calculation formula is as follows:

[0046]

[0047] Current market price of hydrogen, unit: yuan / standard cubic meter (yuan / Nm³).

[0048] The overall hydrogen production efficiency of an electrolytic hydrogen production system represents the amount of hydrogen produced per kilowatt-hour (kWh) of electrical energy consumed, measured in Nm³ / kWh. This value is determined by the performance of the electrolyzer and is its main technical constant.

[0049] Non-electric operating costs corresponding to the unit electricity consumption in the hydrogen production process, including the cost of demineralized water consumption, equipment depreciation and amortization, and routine maintenance, converted to per kilowatt-hour of electricity, in yuan / kWh.

[0050] Plant power consumption rate and grid loss coefficient. Since electrolysis for hydrogen production consumes plant power, this energy can generate revenue if it is used to supply the grid. This coefficient is used to convert the grid electricity price into an equivalent value of the plant power consumption cost, and is usually taken as a small percentage (e.g., 0.02~0.05).

[0051] The second economic threshold (T2) is the critical electricity price for initiating methanol synthesis, and the suggested calculation formula is:

[0052]

[0053] Current methanol market price, unit: yuan / ton.

[0054] : Mass yield of methanol synthesized from hydrogen, unit: tons of methanol / ton of hydrogen. Determined by stoichiometry and catalytic efficiency.

[0055] This item represents the opportunity cost of the electrical energy consumed per unit of hydrogen production. The amount of electricity required to produce 1 standard cubic meter of hydrogen (kWh / Nm³) 3 ), The price of hydrogen is used here as a benchmark for the opportunity cost of generating electricity from hydrogen.

[0056] Internal cost or purchase price of carbon dioxide, unit: yuan / ton.

[0057] CO2 consumption ratio in methanol synthesis, unit: tons of CO2 / ton of methanol.

[0058] Non-raw material variable operating costs of the methanol synthesis unit, in yuan / ton of methanol (including catalyst consumption, additional water consumption, maintenance, etc.).

[0059] Hydrogen production power consumption corresponding to the hydrogen required to produce 1 ton of methanol, unit: kWh / ton of methanol.

[0060] Additional power consumption of the methanol synthesis process itself (such as compressors, circulating pumps, etc.), unit: kWh / ton of methanol.

[0061] III. Multi-mode intelligent collaboration and flexible coupling operation mechanism

[0062] The operating method of this invention is not limited to a single mode of mechanical execution. Its core advancement lies in a multi-mode intelligent collaborative and flexible coupling operating mechanism constructed through an intelligent collaborative control unit. This mechanism is based on a multi-objective real-time optimization model, with the goal of maximizing the overall plant revenue within the future prediction period. By continuously optimizing key variables such as the heat release power of the solid particle thermal storage unit, the hydrogen production power of PEM electrolysis, and the methanol synthesis load rate, the system achieves dynamic decision-making under complex operating conditions.

[0063] In actual operation, the various subsystems of the system do not operate in isolation, but rather in a highly flexible and coupled hybrid state. The intelligent collaborative control unit incorporates a hierarchical decision-making logic that prioritizes grid stability response above all else, followed by optimization of the comprehensive economic efficiency of multi-energy cogeneration, to handle complex operating conditions triggered by multiple concurrent boundary conditions.

[0064] First, under coordinated value-added operating conditions (such as when the grid's deep peak-shaving command coincides with a period of low electricity prices), the control unit triggers a "dual-effect value-added" strategy. The system not only operates the water-hydrogen-oxygen coupling subsystem at full load to absorb surplus electricity, but also links up the load of the carbon-chemical coupling subsystem to convert low-value electricity into high-value green methanol, thereby obtaining grid peak-shaving compensation and maximizing chemical output.

[0065] Second, in emergency situations involving conflict and competition (such as a conflict between a rapid frequency regulation load increase command and a period of high chemical production revenue), the control unit enforces "absolute safety priority." The system instantly treats the electrolysis hydrogen production load as an interruptible load and reduces it accordingly, while simultaneously starting the heat-steam-power coupling subsystem to achieve second-level steam injection into the turbine, ensuring that the unit's power ramp-up rate meets the grid's assessment requirements.

[0066] Third, under normal and stable operating conditions, the system maintains a flexible standby state. For example, when electricity prices are moderate but frequency regulation backup is required, the control unit instructs the solid particle thermal storage unit to maintain high-temperature thermal backup while maintaining low-load hydrogen production to optimize energy efficiency. Through this dynamic adjustment, the system achieves a globally optimal balance of the "electricity-heat-hydrogen-chemical" coupled system while ensuring equipment safety constraints.

[0067] The beneficial effects of this invention are as follows:

[0068] 1. Significantly improved frequency regulation and peak shaving response rate of coal-fired power units: Addressing the technical shortcomings of traditional coal-fired power units, such as high thermal inertia and sluggish load changes, this invention utilizes solid particles to absorb the waste heat of medium-temperature flue gas for sensible heat storage, coupled with a downward moving bed steam generator. This enables rapid steam generation and injection into the turbine within 60-90 seconds of receiving a command. This design decouples the strong correlation between boiler combustion status and turbine output, meeting the requirements of new power systems for second-level frequency regulation while avoiding mechanical fatigue damage to the boiler and turbine rotor caused by frequent load changes.

[0069] 2. Achieved efficient and comprehensive recovery and utilization of plant-wide thermal energy in a tiered manner: This invention constructs a tiered thermal energy utilization network matched to different temperature zones: the first stage recovers waste heat from flue gas at 400-500℃ for high-grade particle thermal storage; the second stage recovers heat from methanol synthesis at 220-250℃, which is directly used to heat boiler feedwater to replace part of the turbine extraction steam; the third stage recovers waste heat from water electrolysis for hydrogen production at 40-60℃ for preheating raw water. Through the deep coupling and quality-based energy utilization of the entire plant's energy flow, the overall energy utilization rate of the entire system can be increased by 10%-15%.

[0070] 3. This invention achieves resource utilization of carbon emissions and improves overall economic benefits: It establishes a fundamental coupling pathway between "water-hydrogen-oxygen" and "carbon-chemicals," utilizing green hydrogen produced through off-peak electrolysis and captured carbon dioxide to synthesize green methanol. This method not only effectively utilizes surplus electricity and reduces plant electricity costs, but also converts CO2, which would otherwise require energy-intensive storage, into high-value-added chemical products. Under typical low electricity price conditions, operating this multi-energy cogeneration mode can improve overall revenue by 30% to 50% compared to the traditional pure power generation mode.

[0071] 4. Improved operational flexibility and coordination of multi-energy coupling systems under complex operating conditions: Relying on an intelligent collaborative control unit with a built-in multi-condition concurrent decision-making mechanism, this system can flexibly switch between modes such as "frequency regulation and load ramping" and "multi-energy co-production and dynamic optimization" based on grid dispatch instructions and real-time price signals. Under the premise of ensuring the absolute priority of grid dispatch (such as deep peak shaving or rapid frequency regulation), the control unit dynamically adjusts the heat release rate of the thermal storage unit, the operating power of the electrolyzer, and the load of the synthesis tower, realizing global optimization under equipment safety constraints. Attached Figure Description

[0072] Figure 1 This is a schematic diagram of the system of the present invention;

[0073] Figure 2 This is the control logic diagram of the present invention. Detailed Implementation

[0074] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited thereto.

[0075] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments.

[0076] like Figure 1 As shown, a water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system includes:

[0077] Coal-fired power generation units are used to provide thermal energy, electrical energy and material resources, including boilers, steam turbines, generators, flue gas treatment modules, chemical water treatment modules, carbon dioxide capture devices and boiler feedwater treatment modules;

[0078] The heat-steam-power coupling subsystem is connected to the flue gas side and steam-water side of the coal-fired power generation unit. It includes a solid particle sensible heat storage and release device and a steam generator, which is used to store sensible heat using the waste heat of flue gas and can quickly generate steam to inject into the steam turbine to increase the power generation of the coal-fired power generation unit.

[0079] The solid particle sensible heat storage and release device includes a flue gas-particle fluidized bed heat exchanger, a low-temperature particle storage tank, and a high-temperature particle storage tank.

[0080] The flue gas-particle fluidized bed heat exchanger has its flue gas side inlet connected to the flue between the economizer and the air preheater;

[0081] The low-temperature particle storage tank is connected to the particle inlet of the flue gas-particle fluidized bed heat exchanger, and the high-temperature particle storage tank is connected to the particle outlet of the flue gas-particle fluidized bed heat exchanger.

[0082] The steam generator is a downward moving bed type steam generator. Its particle inlet is connected to a high-temperature particle storage tank, its feedwater inlet is connected to the boiler feedwater treatment module, and its steam outlet is connected to the steam turbine through a pipeline.

[0083] The water-hydrogen-oxygen coupling subsystem is connected to the plant power module for power supply, the chemical water treatment module of the coal-fired generator set, the flue gas treatment module and the boiler. It includes an electrolytic hydrogen production unit and a second heat exchanger. The water source treated by the chemical water treatment module is electrolyzed to produce hydrogen and oxygen. The oxygen is recycled for enriched combustion in the boiler and / or flue gas desulfurization. The hydrogen is transported to the carbon-coupling subsystem and used as the raw material gas for methanol synthesis. The waste heat of the electrolytic hydrogen production unit is used to preheat the raw water using the second heat exchanger.

[0084] The electrolytic hydrogen production unit of the water-hydrogen-oxygen coupling subsystem includes:

[0085] The proton exchange membrane electrolyzer has its power input connected to the plant power module for power supply, and its material inlet connected to the outlet of the chemical water treatment module.

[0086] The hydrogen processing unit connects the cathode of the proton exchange membrane electrolyzer to the hydrogen inlet of the methanol synthesis reactor, and is used to cool, dry, pressurize and store the produced hydrogen.

[0087] The oxygen recovery unit connects the anode of the proton exchange membrane electrolyzer to the flue gas treatment module and the boiler, and is used to collect and pressurize the produced oxygen.

[0088] The carbon-chemical coupling subsystem is used to catalytically synthesize methanol from hydrogen and captured carbon dioxide, and recover the heat of reaction for heating boiler feedwater. It includes a methanol synthesis reactor and a first heat exchanger. The hydrogen outlet of the electrolytic hydrogen production unit and the outlet of the carbon dioxide capture unit are respectively connected to the methanol synthesis reactor. The methanol synthesis reactor is connected to the first heat exchanger. The first heat exchanger is connected to the boiler feedwater treatment module.

[0089] The methanol synthesis reactor is a shell-and-tube isothermal methanol synthesis reactor. The tubes are filled with catalyst for methanol synthesis, and the shell serves as a heating channel for boiler feedwater. The boiler feedwater treatment module includes a low-pressure heater, a deaerator, and a high-pressure heater connected in sequence. Feedwater at 90-110°C at the outlet of the low-pressure heater flows through the shell to absorb the heat of reaction and is heated to 180-200°C before being injected into the deaerator.

[0090] like Figure 2 As shown, the intelligent collaborative control unit is communicatively connected to the coal-fired power generation unit, the heat-steam-power coupling subsystem, the water-hydrogen-oxygen coupling subsystem, and the carbon-chemical coupling subsystem, respectively. It is used to collaboratively control the operation of each subsystem according to the power grid dispatch instructions, power market signals, resource and market information, and equipment status parameters.

[0091] The intelligent collaborative control unit includes:

[0092] The information perception and fusion layer is used to collect real-time power grid dispatch instructions, power market signals, resource and market information, and equipment status parameters.

[0093] The decision and optimization layer is used to determine the system operation mode based on the collected information and according to the preset decision logic. The decision logic prioritizes responding to the grid emergency command, and when there is no emergency command, it compares the real-time electricity price with the dynamically calculated first economic threshold and second economic threshold, and selects to enter the fast frequency regulation mode, electrolysis hydrogen production mode or methanol synthesis mode.

[0094] The instruction decomposition and control layer is used to convert the operating mode into specific device-level control instructions and issue them for execution.

[0095] The controlled physical equipment layer, as the physical execution end of the intelligent collaborative control unit, is used to receive equipment-level control commands issued by the command decomposition and control layer, and drive each physical device to perform corresponding actions; by adjusting the operating status of the coal-fired power generation unit, the heat-steam-power coupling subsystem, the water-hydrogen-oxygen coupling subsystem and the carbon-chemical coupling subsystem, the system can switch and coordinate between multiple modes.

[0096] The first economic threshold is calculated based on the hydrogen market price, electrolysis hydrogen production efficiency, non-electric operating costs of hydrogen production, and plant power consumption rate. The second economic threshold is calculated based on the methanol market price, hydrogen production cost, carbon dioxide cost, methanol quality and yield, and power consumption of the synthesis process.

[0097] A method for intelligent and flexible operation based on the above system, executed by an intelligent collaborative control unit, includes the following modes:

[0098] Rapid frequency regulation and load ramping mode: When a rapid load increase command is received from the power grid, the control heat-steam-power coupling subsystem is started, and steam is quickly generated using the stored sensible heat and injected into the steam turbine, thereby rapidly improving the unit's power generation efficiency under the condition that the boiler combustion is basically stable.

[0099] Multi-energy cogeneration and dynamic optimization mode: When the real-time electricity price is lower than the first economic threshold, the output of the coal-fired power generation unit is reduced, and the electrolysis hydrogen production load of the water-hydrogen-oxygen coupling subsystem is started or increased to convert electrical energy into hydrogen for storage. When the real-time electricity price is lower than the second economic threshold and the hydrogen reserves are sufficient, the methanol synthesis load of the carbon-carbon coupling subsystem is further started or increased to convert hydrogen and carbon dioxide into methanol.

[0100] It also includes a multi-mode intelligent collaborative and flexible coupling operation mechanism: the intelligent collaborative control unit is based on a multi-objective real-time optimization model, and under the premise of meeting equipment safety constraints, dynamically and collaboratively controls the heat release power of solid particle thermal storage, the operating power of the electrolytic hydrogen production unit and the load rate of the methanol synthesis unit, so as to maximize the overall benefits of the system.

[0101] The intelligent collaborative control unit also dynamically adjusts the load distribution between electrolytic hydrogen production and methanol synthesis based on the remaining hydrogen and carbon dioxide levels and the market price of methanol.

[0102] The heat-steam-power coupling subsystem generates steam at 1.0 to 1.5 MPa within 60 to 90 seconds.

[0103] Example

[0104] This embodiment uses the retrofitting of a 600 MW subcritical coal-fired power generator unit as an example to illustrate the specific operation process of the water-heat-chemical value-added system. The system comprises three stages of heat recovery networks in terms of energy flow. The first-stage heat recovery network extracts medium-temperature flue gas at approximately 450°C from the boiler economizer outlet and introduces it into a gas-solid heat exchanger. There, it undergoes counter-current heat exchange with high-alumina bauxite ceramic particles with an average particle size of 1.0 mm, heating the particles to 420°C before storing them in a high-temperature heat storage tank. The second-stage heat recovery network connects the shell-side cooling loop of the shell-and-tube isothermal methanol synthesis reactor in parallel with the boiler's high-pressure feedwater pipeline. Utilizing the 240°C isothermal reaction heat generated during methanol synthesis, the high-pressure feedwater is preheated from 160°C to 210°C, thereby replacing part of the extracted steam from the turbine's high-pressure cylinder. The third-stage heat recovery network introduces the cooling water circulation loop of the proton exchange membrane electrolyzer into the chemical water treatment workshop, using the 50°C waste heat from electrolysis to preheat the raw water from 15°C to 35°C, thus reducing the steam consumption of the raw water heater.

[0105] During multi-mode intelligent collaborative operation, the system achieves smooth switching of operating conditions through the intelligent collaborative control unit. When the grid is in a deep peak-shaving period at night and during off-peak electricity price periods, such as when the grid dispatch requires the unit to reduce its rated load to 30%, i.e., 180 MW, the control unit determines that the system enters a coordinated operating condition. At this time, the boiler and generator actually maintain an operating condition of 230 MW, and the control unit increases the proton exchange membrane electrolyzer power to its full load of 50 MW, consuming this portion of plant power to reduce the unit's actual grid-connected power to 180 MW. Under this condition, the electrolyzer operates at rated load, producing a large amount of hydrogen, and the carbon-coupling subsystem simultaneously increases its load, consuming hydrogen and captured carbon dioxide to synthesize methanol. In this process, the heat from the methanol reaction replaces high-stage steam extraction and low-grade waste heat is recovered, allowing the unit's heat in the low-load range to be fully utilized.

[0106] When the unit is operating under the aforementioned deep peak-shaving conditions, if the grid experiences a sudden frequency drop and issues a frequency regulation command requiring the unit to increase its output by 30 MW within 2 minutes, the control unit determines that the system has entered a conflict game condition and executes a grid stability priority strategy. Within 2 seconds of receiving the command, the control unit rapidly reduces the operating power of the proton exchange membrane electrolyzer from 50 MW to 5 MW to maintain the equipment's minimum thermal standby, instantly releasing 45 MW of available capacity to the grid. Simultaneously, the control unit opens the flow regulating valve at the bottom of the downward moving bed steam generator. High-temperature particles at 420°C in the heat storage tank enter the heat exchange tube bundle area under gravity, exchanging heat with the feedwater in the tubes and generating superheated steam at 380°C and 3.5 MPa within 75 seconds. This superheated steam is directly injected into the intermediate-pressure cylinder of the turbine through the control valve to perform work.

[0107] The aforementioned system has achieved significant implementation results in actual operation. Regarding response speed, traditional coal-fired units adjust the load by regulating boiler coal feed and air volume, resulting in a response time typically of 3 to 5 minutes due to thermal inertia. This system, however, shortens the unit's power response time to 75 seconds through the coordinated action of cutting off the flexible load of the electrolyzer and releasing the granular thermal storage steam, meeting the requirements of the new power system for secondary frequency regulation. In terms of energy saving and consumption reduction, by using the heat of methanol synthesis reaction in a cascade manner to replace high-pressure steam extraction from the turbine, the steam flow rate for turbine operation is increased. Calculations show that this can reduce the unit's standard coal consumption for power generation by approximately 3.5 grams per kilowatt-hour under full-capacity operating conditions. Simultaneously, using waste heat from electrolysis to preheat raw water saves on auxiliary heating steam supply annually. In terms of economic benefits, utilizing off-peak electricity prices to produce hydrogen and synthesize high-value-added methanol offsets the operating costs of the carbon dioxide capture process, improving the overall economic benefits of the unit during low-load peak-shaving periods.

Claims

1. A water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system, characterized in that, include: A coal-fired power generation unit includes a boiler, a steam turbine, a generator, a flue gas treatment module, a chemical water treatment module, a carbon dioxide capture device, and a boiler feedwater treatment module. The heat-steam-power coupling subsystem is connected to the flue gas side and steam-water side of the coal-fired generator set. It is used to store waste heat from the flue gas and quickly generate steam to inject into the steam turbine to improve the power generation of the coal-fired generator set. The water-hydrogen-oxygen coupling subsystem is connected to the plant power module, chemical water treatment module, flue gas treatment module and boiler. It includes an electrolysis hydrogen production device that electrolyzes water to produce hydrogen and oxygen, and uses the oxygen back for boiler enrichment combustion and / or flue gas desulfurization. The hydrogen is transported to the carbon-coupling subsystem and used as the feed gas for methanol synthesis. A carbon-chemical coupling subsystem for the catalytic synthesis of methanol from hydrogen and captured carbon dioxide, and for the recovery of reaction heat for heating boiler feedwater, including a methanol synthesis reactor; The intelligent collaborative control unit communicates with the coal-fired power generation unit and each subsystem to collaboratively control the operation of each subsystem.

2. The water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system as described in claim 1, characterized in that, The heat-steam-power coupling subsystem includes a solid particle sensible heat storage and release device and a steam generator. The solid particle sensible heat storage and release device includes a flue gas-particle fluidized bed heat exchanger, a low-temperature particle storage tank and a high-temperature particle storage tank. The flue gas-particle fluidized bed heat exchanger has its flue gas side inlet connected to the flue between the economizer and the air preheater; The low-temperature particle storage tank is connected to the particle inlet of the flue gas-particle fluidized bed heat exchanger, and the high-temperature particle storage tank is connected to the particle outlet of the flue gas-particle fluidized bed heat exchanger. The steam generator is a downward moving bed type steam generator. Its particle inlet is connected to a high-temperature particle storage tank, its feedwater inlet is connected to a boiler makeup water treatment module, and its steam outlet is connected to a steam turbine through a pipeline.

3. The water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system as described in claim 1, characterized in that, The electrolytic hydrogen production unit of the water-hydrogen-oxygen coupling subsystem includes: The proton exchange membrane electrolyzer has its power input connected to the plant power module for power supply, and its material inlet connected to the outlet of the chemical water treatment module. The hydrogen processing unit connects the cathode of the proton exchange membrane electrolyzer to the hydrogen inlet of the methanol synthesis reactor, and is used to cool, dry, pressurize and store the produced hydrogen. The oxygen recovery unit connects the anode of the proton exchange membrane electrolyzer to the flue gas treatment module and the boiler, and is used to collect and pressurize the produced oxygen. The water-hydrogen-oxygen coupling subsystem also includes a second heat exchanger, which is used to preheat the raw water by using the waste heat from the electrolysis hydrogen production unit.

4. The water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system as described in claim 1, characterized in that, The carbon-chemical coupling subsystem also includes a first heat exchanger. The hydrogen outlet of the electrolytic hydrogen production unit and the carbon dioxide capture unit outlet are respectively connected to the methanol synthesis reactor. The methanol synthesis reactor is connected to the first heat exchanger, which is connected to the boiler feedwater treatment module. The methanol synthesis reactor is a shell-and-tube isothermal methanol synthesis reactor. Its tubes are filled with catalyst for methanol synthesis, and its shell serves as a heating channel for boiler feedwater. The boiler feedwater treatment module includes a low-pressure heater, a deaerator, and a high-pressure heater connected in sequence. Feedwater at 90~110°C at the outlet of the low-pressure heater flows through the shell to absorb the heat of reaction and is heated to 180~200°C before being injected into the deaerator.

5. The water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system as described in claim 1, characterized in that, The intelligent collaborative control unit includes: The information perception and fusion layer is used to collect real-time power grid dispatch instructions, power market signals, resource and market information, and equipment status parameters. The decision and optimization layer is used to determine the system operation mode based on the collected information and according to the preset decision logic. The decision logic prioritizes responding to the grid emergency command, and when there is no emergency command, it compares the real-time electricity price with the dynamically calculated first economic threshold and second economic threshold, and selects to enter the fast frequency regulation mode, electrolysis hydrogen production mode or methanol synthesis mode. The instruction decomposition and control layer is used to convert the operating mode into specific device-level control instructions and issue them for execution. The controlled physical equipment layer, as the physical execution end of the intelligent collaborative control unit, is used to receive equipment-level control commands issued by the command decomposition and control layer, and drive each physical device to perform corresponding actions; by adjusting the operating status of the coal-fired power generation unit, the heat-steam-power coupling subsystem, the water-hydrogen-oxygen coupling subsystem and the carbon-chemical coupling subsystem, the system can switch and coordinate between multiple modes.

6. The water-heat-chemical value-added system for coal-fired power plants oriented towards a new type of power system as described in claim 5, characterized in that, The first economic threshold is calculated based on the hydrogen market price, electrolysis hydrogen production efficiency, non-electric operating costs of hydrogen production, and plant power consumption rate. The second economic threshold is calculated based on the methanol market price, hydrogen production cost, carbon dioxide cost, methanol quality and yield, and power consumption of the synthesis process.

7. A method for intelligent and flexible operation of the system based on any one of claims 1-6, characterized in that, The intelligent collaborative control unit executes the following modes: Rapid frequency regulation and load ramping mode: When a rapid load increase command is received from the power grid, the control heat-steam-power coupling subsystem is started, and steam is quickly generated using the stored sensible heat and injected into the steam turbine, thereby rapidly improving the unit's power generation efficiency under the condition that the boiler combustion is basically stable. Multi-energy cogeneration and dynamic optimization mode: When the real-time electricity price is lower than the first economic threshold, the output of the coal-fired power generation unit is reduced, and the electrolysis hydrogen production load of the water-hydrogen-oxygen coupling subsystem is started or increased to convert electrical energy into hydrogen for storage. When the real-time electricity price is lower than the second economic threshold and the hydrogen reserves are sufficient, the methanol synthesis load of the carbon-carbon coupling subsystem is further started or increased to convert hydrogen and carbon dioxide into methanol.

8. The operating method as described in claim 7, characterized in that, In the multi-energy co-production and dynamic optimization mode, the intelligent collaborative control unit also dynamically adjusts the load distribution of electrolytic hydrogen production and methanol synthesis based on the remaining hydrogen, carbon dioxide, and methanol market prices.

9. The operating method as described in claim 7, characterized in that, It also includes a multi-mode intelligent collaborative and flexible coupling operation mechanism: the intelligent collaborative control unit is based on a multi-objective real-time optimization model, and under the premise of meeting equipment safety constraints, dynamically and collaboratively controls the heat release power of solid particle thermal storage, the operating power of the electrolytic hydrogen production unit and the load rate of the methanol synthesis unit, so as to maximize the overall benefits of the system.

10. The operating method as described in claim 7, characterized in that, In the rapid frequency regulation and load ramping mode, the heat-steam-power coupling subsystem generates 1.0~1.5MPa of steam within 60~90 seconds.

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