Thermal power generating unit peak regulation system and method based on cold and hot energy storage

Abstract

The invention relates to a thermal power generating unit peak shaving system and method based on cold and hot energy storage. The thermal power generating unit peak shaving system comprises a boiler, a steam turbine, a power generator, a condenser, a refrigerating machine, a cold storage tank, a heat storage tank and a low-pressure heater. Part of condensed water is pumped at an inlet of a condensed water pump, a condensed water cooling loop is newly built, and in the load valley period or the electricity price valley period, a refrigerator is driven by off-peak electricity to cool the part of condensed water, and the part of condensed water is stored in a large cold storage tank; heat generated in the working process of the refrigerating machine is stored through the heat storage tank; and in the load peak period or the electricity price peak period, low-temperature condensed water is injected into the condenser in an atomization spraying mode through the variable frequency pump set, and the vacuum degree of the condenser is improved. And meanwhile, heat in the heat storage tank is introduced into the low-pressure heater so as to increase the feed water temperature.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of power generation and power supply, and particularly relates to a thermal power unit peak shaving system and method based on cold and hot dual energy storage. BACKGROUND

[0002] To achieve the "double carbon" goal, the installed capacity of renewable energy represented by wind power and photovoltaic power has rapidly increased, but its inherent intermittency and volatility also directly challenges the stability of the power system. At the same time, under the macro background of energy structure transformation, the role of traditional thermal power is undergoing profound reconstruction: from the main power supply that used to bear the basic power supply, it is accelerating to become a supporting power supply that provides flexible adjustment capability to the system. However, the transformation practice faces a real dilemma.

[0003] As the utilization hours continue to decline and the load rate drops significantly, thermal power units frequently operate at low load conditions, leading to increased coal consumption, increased costs, and intensified equipment wear and tear, falling into a dilemma of "more power generation, more loss, and no power generation, loss of value". To break out of this dilemma, we must rely on technological innovation and mode upgrading, focusing on "energy storage + thermal power" cooperation, thermal energy cascade utilization and other paths to optimize unit operation mode and reshape value creation capability, so as to find the right positioning in the new power system and achieve sustainable development.

[0004] The existing energy storage scheme is generally a molten salt heat storage scheme, which is complex, involves high-temperature, anti-condensation and other special technologies, and has high investment, usually reaching tens of millions to hundreds of millions of yuan. The medium is high-temperature molten salt, which has the risk of burns, corrosion and solidification. The preheating is slow, the thermal inertia is large, it is suitable for long-term stable output, it needs to be directly coupled with the thermal system, the fault may affect the main machine, the operation and maintenance are highly professional, the cost is high, and it is used for "thermal decoupling" and other complex modifications, with a long investment recovery period.

[0005] The present application provides a thermal power unit peak shaving system and method based on cold and hot dual energy storage, which includes a boiler, a steam turbine, a generator, a condenser, a refrigerator, a cold storage tank, a heat storage tank and a low-pressure heater. A portion of the condensate water is extracted at the inlet of the condensate pump, a condensate water cooling loop is newly built, and during the low load valley or low electricity price period, the refrigerator is driven by low valley electricity to cool the condensate water, which is stored in a large cold storage tank. The heat generated during the operation of the refrigerator is stored in the heat storage tank. During the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the form of atomized spray through the frequency conversion pump group to improve the vacuum degree of the condenser. At the same time, the heat in the heat storage tank is introduced into the low-pressure heater to increase the temperature of the feed water. SUMMARY

[0006] The present application aims to provide a thermal power unit peak shaving system based on cold and hot dual energy storage to solve the existing dilemma of "more power generation, more loss, and no power generation, loss of value".

[0007] The technical scheme provided by the present application to solve its technical problems is as follows: A thermal power unit peak shaving system based on cold and hot dual energy storage, comprising a condenser, a boiler, a steam turbine and a generator, further comprising a cold storage tank, a refrigerator, a first heat exchanger, a heat storage tank and a second heat exchanger, the boiler generates high-temperature and high-pressure steam by heating with coal, gas, oil or electricity, the high-temperature and high-pressure steam drives the steam turbine to rotate, the steam turbine drives the generator to generate electricity when rotating, the high-temperature and high-pressure steam becomes exhaust steam after passing through the steam turbine and enters the condenser to condense into water, maintaining the vacuum degree in the condenser; During the valley of electricity consumption, part of the electricity generated by the generator drives the refrigerator to refrigerate, and the cold energy is stored in the cold storage tank, and the heat energy is stored in the heat storage tank through the first heat exchanger and the heat storage tank; During the peak of electricity consumption, the cold energy stored in the cold storage tank provides cold energy for the condenser, accelerating the speed of exhaust steam condensing into water in the condenser, further improving the vacuum degree in the condenser; the heat energy stored in the heat storage tank provides heat energy for the water flowing back to the boiler through the second heat exchanger, accelerating the vaporization speed and heating temperature of the water in the boiler, thereby improving the power generation of the generator during the peak of electricity consumption.

[0008] Preferably, by modeling the variable condition of the condenser, a heat transfer model is established to quantify the relationship between cooling load and vacuum degree, and the target is to improve the vacuum degree greater than 0.25kPa; A "steam turbine-condenser-cold and heat storage" coupling model is constructed to evaluate the influence of start-stop / regulation on the safety boundary of the generator; Performing exergy analysis and energy efficiency evaluation: calculate the exergy loss of the whole process of cold and heat storage from the "energy quality" angle, identify the bottleneck, and demonstrate the rationality of the technical route.

[0009] A thermal power unit peak shaving method based on cold and heat dual energy storage, characterized in that it comprises a condensate water recooling system coupled with cold storage of the thermal power unit and a boiler backflow water heating system with heat storage, and the overall architecture of the system is composed of five core parts, namely, a refrigeration device, a cold storage tank and a heat storage tank, a special variable frequency pump set, a spraying device and an intelligent control system; part of the condensate water is extracted at the inlet of the condensate water pump, a new condensate water cooling loop is established, and during the load low valley or electricity price low valley period, the condensate water is cooled by the refrigeration machine driven by the low valley electricity and stored in the large cold storage tank; a second heat exchanger is arranged on the outlet pipeline of the condensate water pump to build the heating structure of the condensate water backflow loop, and during the load low valley or electricity price low valley period, the heat generated by the refrigeration machine is stored in the large heat storage tank through the first heat exchanger, and the heat storage tank can heat the condensate water in the condensate water backflow loop through the second heat exchanger, so as to increase the temperature of the condensate water backflowing into the boiler; during the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the form of atomized spraying through the variable frequency pump set, the vacuum degree of the condenser is improved, and the condensate water backflowing into the boiler is heated through the second heat exchanger, so as to increase the power generation during the load peak or electricity price peak period.

[0010] The refrigeration machine, the cold storage tank, the pipeline and the corresponding pipeline for providing cold to the condenser and the pump constitute a condensate water recooling mechanism; the condensate water recooling mechanism is used for providing cold to the condenser, and the power generation of the generator is increased during the power peak or the power peak value.

[0011] Preferably, the condenser is modeled by changing the working condition, a heat transfer model is established, the relationship between the cooling load and the vacuum degree is quantified, and the target vacuum degree is greater than 0.5 kPa; A "turbine-condenser-cold storage and heat storage" coupling model is constructed to evaluate the influence of start-stop / regulation on the safety boundary of the generator; Performing exergy analysis and energy efficiency evaluation: calculate the exergy loss of the whole cold storage process from the "energy quality" angle, identify the bottleneck, and demonstrate the rationality of the technical route.

[0012] Preferably, the condensate water pipeline, the shunt valve, the condensate water pump, the variable frequency pump two and the cold taking pipeline are further included. The exhaust steam of the condenser becomes condensate water, passes through the shunt valve, part of the condensate water can enter the boiler through the condensate water pipeline and the condensate water pump, and the other part of the condensate water can enter the cold storage tank through the cold taking pipeline and the variable frequency pump two to further reduce the temperature to become low-temperature condensate water with a temperature of 10-20℃, and the low-temperature condensate water can enter the condenser again through the condensate water feeding pipeline, so as to accelerate the speed of condensation of the exhaust steam into water, improve the vacuum degree of the condenser, and further improve the power generation of the thermal power unit peak shaving system based on cold and heat dual energy storage.

[0013] Preferably, the cold storage tank further reduces the temperature of the condensate water to 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃ and 19.5℃.

[0014] Preferably, the chiller provides heat to the first heat exchanger through the first exhaust pipe, and the first heat exchanger provides heat to the heat storage tank; the heat storage tank provides heat to the water flowing back to the boiler through the second heat exchanger, and a circulating water pump and a hot water pipeline are arranged between the heat storage tank and the second heat exchanger.

[0015] Preferably, the condensate water is taken by a variable frequency pump two, a shunt valve and a cold water pipeline; The return water design is realized by a condensate water pipeline; The water taking design and the return water design do not affect the safe operation of the steam turbine and the generator.

[0016] Preferably, it further comprises a variable frequency pump one and a cold storage pipeline, and the cold energy generated by the refrigerant driven by the variable frequency pump one is stored in the cold storage tank through the cold storage pipeline.

[0017] Preferably, the condenser is provided with an atomizer, and the low-temperature condensate water enters the condenser in the form of atomized spray through the atomizer.

[0018] Preferably, the cold storage tank is an open atmospheric steel tank, and a water distributor is arranged inside to realize temperature stratification, so as to ensure efficient storage and extraction of cold energy; the effective volume of the tank meets the cold release demand for more than 1 hour during the peak period; the tank wall of the cold storage tank is made of polyurethane foam insulation, and a floating top cover or a covering ball is arranged at the top to reduce evaporation loss and cold energy loss, so as to ensure that the temperature rise within 24 hours is not more than 1℃.

[0019] Preferably, the variable frequency pump two and the variable frequency pump one are configured in one active and one standby or two active and one standby mode, the single pump flow is determined according to the designed cold energy, and the head is calculated according to the system resistance. The water pump is equipped with a high-performance frequency converter to realize soft start and stop and accurate flow regulation.

[0020] Preferably, the cold storage tank adopts temperature stratification design; a water distributor structure is arranged in the cold storage tank; the water distributor structure is provided with a stable temperature gradient maintaining structure, the cold storage efficiency is >95%, and the 24h temperature rise is <1℃; The COP of the centrifuge part of the chiller is optimized under part load, and the valley electricity is efficiently stored; a complex pipe network hydraulic optimization model is established to optimize the pipe diameter / valve / connection point, avoid hydraulic imbalance, and ensure fault isolation; The overall intelligent control system adopts an intelligent prediction control strategy and algorithm optimization oriented to multi-objective optimization, and adopts a three-layer control architecture: day-ahead optimization (electricity price / weather / power generation plan) → real-time rolling (load fluctuation correction) → second-level closed loop (MPC pump / valve control); Cold and electricity price prediction: LSTM / Transformer predicts ambient temperature, unit load, electricity price, error <5%; Intelligent operation and fault diagnosis: data-driven early warning of chiller attenuation, pump vibration, and fouling; build operation knowledge base to improve availability.

[0021] Preferably, the condenser is provided with cold from the cold storage tank to accelerate the process of condensing the exhaust steam into water, and the vacuum degree of the condenser is increased by more than 0.25 kPa.

[0022] Preferably, the vacuum degree of the condenser is increased by more than 0.5 kPa.

[0023] A control system of a thermal power unit peak regulation system based on cold and heat dual energy storage, the overall architecture of the system is composed of five core parts: refrigeration devices, cold storage tanks, special frequency conversion pump sets, spraying devices, and intelligent control systems; part of the condensate water is extracted at the inlet of the condensate pump, a new condensate water cooling loop is built, and during the load low valley or electricity price low valley period, the low valley electricity drives the chiller to cool the part of the condensate water, and stores it in the large cold storage tank; during the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the form of atomized spraying through the frequency conversion pump set, the vacuum degree of the condenser is increased, and the power generation during the load peak or electricity price peak period is improved.

[0024] Preferably, the cold storage tank adopts temperature stratification design; a water distributor structure is arranged in the cold storage tank; the water distributor structure is provided with a stable temperature gradient layer maintaining structure, the cold storage efficiency is >95%, and the 24h temperature rise is <1℃; The COP of the centrifuge part of the chiller is optimized under partial load, and the valley electricity is efficiently stored; a complex pipe network hydraulic optimization model is established to optimize the pipe diameter / valve / connection point, avoid hydraulic imbalance, and ensure fault isolation; Preferably, the overall intelligent prediction control strategy and algorithm optimization are multi-objective optimization oriented, and a three-layer control architecture is adopted: day-ahead optimization (electricity price / weather / power generation plan) → real-time rolling (load fluctuation correction) → second-level closed loop (MPC pump / valve control); Cold and electricity price prediction: LSTM / Transformer predicts ambient temperature, unit load, electricity price, error <5%; Intelligent operation and fault diagnosis: data-driven early warning of chiller attenuation, pump vibration, and fouling; build operation knowledge base to improve availability.

[0025] The core control strategy of the system is fuzzy PID control based on constant temperature difference and demand prediction; the control target is to identify the cooling load change in real time, dynamically adjust the cold storage / cooling release working condition, avoid main cycle disturbance, and ensure system stability; The control system adopts a distributed control system or an intelligent control system based on PLC as a brain, and the hardware core includes a PLC controller, a frequency converter, a temperature sensor, a pressure sensor, a flow sensor, and an electric actuator, etc.; the sensors should be installed on the outlet of the refrigeration machine, the inlet and outlet of the cold storage tank, the water inlet branch pipe of the condenser, and the main water return pipe, to monitor the temperature, pressure, flow, and other parameters in real time; The system network architecture is divided into a device layer, a control layer, and a monitoring layer. The device layer is composed of a frequency converter, a sensor, and an actuator, responsible for data acquisition and instruction execution; the control layer receives signals from the device layer by PLC, executes the predetermined control logic, and outputs the frequency signal to control the water pump and the refrigeration machine; the monitoring layer is configured with a man-machine interface and a monitoring computer, located in the power plant control room, providing the operator with a system panoramic view and parameter setting interface, and can be connected to the main control system of the power plant to realize collaborative management.

[0026] The application relates to a thermal power unit peak regulation system based on cold and hot dual energy storage, wherein high-temperature and high-pressure steam generated by a boiler drives a steam turbine to rotate, drives a generator to generate power, and after passing through the steam turbine, the high-temperature and high-pressure steam becomes exhaust steam and enters a condenser to be condensed into water, so that the vacuum degree in the condenser is maintained; the power generated by the generator is partially used to drive a refrigeration machine to refrigerate, and the refrigeration capacity is stored in a cold storage tank, so that the power generation capacity of the generator during the power peak period is improved, and the power demand during the power peak period is met; the overall architecture of the control system is composed of five core parts, i.e., a refrigeration device, a cold storage tank, a special frequency conversion pump set, a spraying device and an intelligent control system; and the working process is as follows: part of the condensate water is extracted at the inlet of the condensate water pump, a new condensate water cooling loop is established, and during the load low valley or the electricity price low valley period, the refrigeration machine is driven by the low valley electricity to cool the part of the condensate water, and the condensate water is stored in the large cold storage tank; during the load peak or the electricity price peak period, the low-temperature condensate water is injected into the condenser in the atomizing spraying mode through the frequency conversion pump set, so that the vacuum degree of the condenser is improved, and the power generation capacity is improved.

[0027] The application relates to the technical field of thermal power generation, and relates to a peak regulation system and method for improving the operation efficiency of an air-cooled thermal power unit during a load peak period and in a high-temperature environment.

[0028] The air-cooled thermal power unit is widely used in coal-rich and water-short areas in China due to its water-saving advantage. However, the cooling efficiency of the air-cooling island of the air-cooled thermal power unit seriously depends on the ambient temperature and the wind speed. In summer high-temperature or windless weather, the heat dissipation capacity of the air-cooling island sharply decreases, the vacuum degree of the condenser deteriorates, the power generation efficiency of the unit is reduced, the output is limited, and the power supply capacity of the power grid during the peak load period in summer is seriously affected. Meanwhile, the unit is operated during the night load low valley period, the power generation load rate is low, and the peak regulation capacity of the unit is not fully utilized.

[0029] In the prior art, there are proposals to spray atomized water to the condenser to assist in cooling, but the water source is usually normal temperature water, the cooling effect is limited, and the time-space transfer of energy cannot be realized. Another proposal is to set up a large refrigeration station in the plant, but the direct operation energy consumption is high, and the economy is poor. At present, there is no comprehensive solution to convert electric energy during the load low period into cold energy and heat energy and store them respectively for simultaneously improving the condenser vacuum and reducing the steam extraction consumption during the peak period.

[0030] In view of the deficiencies of the prior art, the present application aims to provide a kind of air-cooled thermal power unit peak shaving system and method based on cold and hot dual energy storage. The system can store energy during the load low period, release energy during the load peak period, improve the output and efficiency of the unit from the "cold" and "hot" dimensions, realize the cascade utilization and time-space transfer of energy, and significantly enhance the peak shaving capacity and economy of the unit.

[0031] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: In the first aspect, an air-cooled thermal power unit peak shaving system based on cold and hot dual energy storage is provided, comprising an air cooling island and a steam turbine regenerative system, further comprising: 1. Cold energy storage and release circuit: Refrigeration unit: the evaporator side thereof is connected with a cold water storage tank through a pipeline, forming a refrigeration cycle.

[0032] Spraying device: arranged inside the steam space of the air-cooled condenser or in the inlet air deflector, connected with the cold water storage tank through a pipeline and a pump, and a control valve is arranged on the pipeline.

[0033] 2. Heat energy storage and utilization circuit: Heat storage device: used for storing waste heat discharged from the condenser side of the refrigeration unit, connected with the condenser side of the refrigeration unit through a first heat exchanger, forming a heat storage cycle.

[0034] Feedwater heating circuit: the heat storage device is connected with the low-pressure feedwater pipeline of the steam turbine regenerative system through a second heat exchanger, forming a feedwater heating cycle.

[0035] 3. Control system: connected with the refrigeration unit, pump, control valve, and load signal and environmental monitoring signal of the unit, used for controlling the start-stop and energy distribution of the whole system according to the preset strategy.

[0036] Preferably, the spray head of the spraying device is an atomizing spray head to ensure sufficient vaporization and efficient heat exchange of the cold water.

[0037] Preferably, the heat storage device is a normal-pressure hot water storage tank or a phase-change heat storage tank.

[0038] Preferably, the access point of the feedwater heating circuit is located on the pipeline between the condensate pump at the outlet of the condenser hotwell and the first low-pressure heater.

[0039] In a second aspect, a peak shaving method based on the above system is provided, comprising the following steps: Energy storage phase (low load period): Start the refrigeration unit, cool part of the condensate water from the condenser hotwell or outside to low-temperature cold water, and store it in the cold water storage tank.

[0040] At the same time, the waste heat discharged by the refrigeration unit is stored in the heat storage device through the first heat exchanger.

[0041] Energy release phase (high load period or high temperature period): Cold energy release: open the control valve and start the pump, atomize the low-temperature cold water in the cold water storage tank into the air-cooled condenser through the spraying device, directly absorb the exhaust heat, reduce the condenser back pressure, and improve the vacuum degree.

[0042] Heat energy release: transfer the heat stored in the heat storage device to the low-pressure feedwater of the steam turbine regenerative system through the second heat exchanger, increase the feedwater temperature, and thus reduce the consumption of corresponding low-pressure extraction steam, so that more steam is expanded in the steam turbine to do work.

[0043] Advantages of the present application Compared with the prior art, the present application has the following significant advantages: 1. Energy efficiency is doubled, and peak shaving is deep: the electric energy consumed during the low load period is converted into "cold energy" and "heat energy" at the same time, which are two high-value energy storage. At the same time, release during peak period, improve unit output from two core paths of improving vacuum and reducing extraction, realize the synergistic effect of "1+1>2", and deeply tap the peak shaving potential of the unit.

[0044] 2. Energy time-space transfer, outstanding economic benefits: perfect use of the peak and valley price difference of the power grid. Use electricity to store energy during the low night price valley period, and create excess income through over-generation during the high day price peak period, with high investment return rate.

[0045] 3. Strong environmental adaptability: completely overcome the world-wide problem of performance deterioration of air-cooled units in high-temperature and windless weather. The spraying cooling effect is almost not affected by the ambient temperature, providing reliable protection for safe and stable full-load operation of the unit in extreme weather.

[0046] 4. Energy cascade utilization, high system efficiency: innovatively recycles the condensing heat of the refrigeration machine which is usually discarded, and uses it for the thermal cycle of the power plant, realizing "eating dry and squeezing full", and greatly improving the comprehensive energy utilization efficiency of the whole plant.

[0047] During the low load period, the control system starts the refrigeration unit. A portion of the condensate water is drawn from the condenser hotwell and cooled to 10-15°C in the evaporator of the refrigeration unit 7, and then stored in the cold water storage tank. At the same time, the waste heat of about 45-50°C generated by the condenser of the refrigeration unit 7 is transferred to the water in the thermal storage device (such as a large insulated hot water tank) through the first heat exchanger (which can be a plate heat exchanger).

[0048] During the high load period or high ambient temperature period, the control system first opens the pipeline valve leading to the spraying device, atomizes the 8-15°C cold water, and sprays it into the steam space of the air-cooled condenser to rapidly reduce the back pressure. At the same time, the circulating pump of the thermal storage device is started, and the stored hot water is used to heat the condensate water from the condensate pump through the second heat exchanger, thereby increasing the temperature of the condensate water and reducing the steam extraction amount from the low-pressure heater of the steam turbine, thereby increasing the power generation.

[0049] Preferably, the system includes an air-cooled island and a steam turbine regenerative system, and further includes a cold energy storage and release circuit including the refrigeration unit, the cold water storage tank, and a spraying device arranged in the air-cooled condenser, a thermal energy storage and utilization circuit including a thermal storage device for collecting the condensation heat of the refrigeration unit, and a feedwater heating circuit for introducing the heat in the thermal storage device into the steam turbine regenerative system.

[0050] Preferably, the thermal energy storage and utilization circuit includes a first heat exchanger connected between the condensation side of the refrigeration unit and the thermal storage device, and a second heat exchanger connected between the thermal storage device and the low-pressure feedwater pipeline of the steam turbine regenerative system.

[0051] Preferably, the access point of the feedwater heating circuit is located on the pipeline between the condensate pump at the outlet of the condenser hotwell and the first low-pressure heater.

[0052] Preferably, the spraying device is an atomizing nozzle arranged inside the steam space of the air-cooled condenser or in the inlet air flow guide cover of the air-cooled island.

[0053] Preferably, the thermal storage device is a normal-pressure hot water storage tank or a phase-change thermal storage tank.

[0054] A peak regulation method, comprising: During the low load period of the unit, starting the refrigeration unit to perform cold storage and heat storage; During the high load period or high ambient temperature period of the unit, the following operations are performed simultaneously: a) releasing cold energy: spraying the cold water in the cold water storage tank into the air-cooled condenser through the spraying device; b) releasing thermal energy: using the heat in the thermal storage device to heat the feedwater in the steam turbine regenerative system.

[0055] The beneficial effects of the present application include: The condensate water recooling system coupled with cold storage of a thermal power unit is composed of five core parts, i.e., a refrigeration device, a cold storage tank, a special variable frequency pump set, a spraying device and an intelligent control system. The working process is as follows: part of the condensate water is extracted at the inlet of the condensate pump, a new condensate water cooling circuit is established, and the condensate water is stored in the large cold storage tank by driving the refrigeration machine with off-peak electricity during the load valley or electricity price valley period; the low-temperature condensate water is injected into the condenser in the form of atomized spraying by the variable frequency pump set during the load peak or electricity price peak period, so as to improve the vacuum degree of the condenser.

[0056] A thermal power unit peak regulation system based on cold and heat dual energy storage includes a condenser, a boiler, a steam turbine and a generator, and further includes a cold storage tank and a refrigeration machine. The boiler generates high-temperature and high-pressure steam by heating with coal, gas, oil or electricity, the high-temperature and high-pressure steam drives the steam turbine to rotate, the steam turbine drives the generator to generate electricity when rotating, the high-temperature and high-pressure steam becomes exhaust steam after passing through the steam turbine and is condensed into water in the condenser to maintain the vacuum degree in the condenser. During the electricity valley, part of the electricity generated by the generator drives the refrigeration machine to refrigerate, and the cold energy is stored in the cold storage tank; during the electricity peak, the cold energy stored in the cold storage tank provides cold energy for the condenser to accelerate the speed of the exhaust steam being condensed into water in the condenser, further improve the vacuum degree in the condenser, and thus improve the power generation of the generator during the electricity peak. Or, during the electricity peak, the refrigeration machine also refrigerates, and the cold energy is stored in the cold storage tank, the cold energy stored in the cold storage tank provides cold energy for the condenser to accelerate the speed of the exhaust steam being condensed into water in the condenser, further improve the vacuum degree in the condenser, and thus improve the power generation of the generator during the electricity peak to meet the electricity demand during the electricity peak. BRIEF DESCRIPTION OF DRAWINGS

[0057] The application will be further described below with reference to the drawings.

[0058] Figure 1 is a structure schematic diagram of one embodiment of a thermal power unit peak regulation system based on cold and heat dual energy storage provided by the embodiments of the application.

[0059] Figure 2 is a structure schematic diagram of one embodiment of a thermal power unit peak regulation system based on cold and heat dual energy storage provided by the embodiments of the application.

[0060] Figure 3 is a structure schematic diagram of another embodiment of a thermal power unit peak regulation system based on cold and heat dual energy storage provided by the embodiments of the application.

[0061] IDENTIFICATION OF DRAWINGS: 11 - condenser; 12 - boiler; 13 - steam turbine; 14 - generator; 15 - cooling tower; 16 - circulating water pump; 17 - cooling pipeline; 2 - cold storage tank; 21 - variable frequency pump one; 22 - cold storage pipeline; 3 - refrigeration machine; 31 - first exhaust pipe; 41 - condensate water pipeline; 42 - condensate water pump; 43 - variable frequency pump two; 44 - cold taking pipeline; 45 condensate water feeding pipeline; 5 - flow divider; 7 - first heat exchanger; 8 - heat storage tank; 81 - circulating water pump; 82 - hot water pipeline; 9 - second heat exchanger. DETAILED DESCRIPTION

[0062] The technical solutions of the present application will be described below in conjunction with the accompanying drawings of the present application. Figures 1-3 It is obvious that the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of the present application.

[0063] A thermal power unit peak shaving system based on cold and hot dual energy storage, comprising a condenser 11, a boiler 12, a steam turbine 13 and a generator 14, further comprising a cold storage tank 2 and a refrigeration machine 3, the boiler 12 generates high-temperature and high-pressure steam by heating with coal, gas, oil or electricity, the high-temperature and high-pressure steam drives the steam turbine 13 to rotate, the steam turbine 13 drives the generator 14 to generate electricity when rotating, the high-temperature and high-pressure steam becomes exhaust steam after passing through the steam turbine 13 and is condensed into water in the condenser 11, and the vacuum degree in the condenser 11 is maintained; At the electricity valley, part of the electricity generated by the generator 14 drives the refrigeration machine 3 to refrigerate, and the cold energy is stored in the cold storage tank 2; at the electricity peak, the cold energy stored in the cold storage tank 2 provides cold energy for the condenser 11, accelerates the condensation speed of the exhaust steam in the condenser 11, further improves the vacuum degree in the condenser 11, and thus improves the electricity generation of the generator 14 at the electricity peak; Or, at the electricity peak, the refrigeration machine 3 also refrigerates, and the cold energy is stored in the cold storage tank 2, the cold energy stored in the cold storage tank 2 provides cold energy for the condenser 11, accelerates the condensation speed of the exhaust steam in the condenser 11, further improves the vacuum degree in the condenser 11, and thus improves the electricity generation of the generator 14 at the electricity peak.

[0064] In the embodiment, the refrigeration machine 3, the cold storage tank 2, the cold storage pipeline, and the corresponding pipeline and pump for providing cold energy for the condenser 11 constitute a condensate water refrigeration mechanism; the condensate water refrigeration mechanism is used for providing cold energy for the condenser 11, accelerating the condensation speed of the exhaust steam, improving the electricity generation power of the generator at the electricity peak or the electricity peak.

[0065] In the embodiment, by modeling the variable working condition of the condenser 11, a heat transfer model is established, the relationship between the cooling load and the vacuum degree is quantified, and the target is to improve the vacuum degree to be greater than 0.5 kPa. The heat transfer model can also be established by modeling the variable working condition of the condenser 11 according to the need, quantifying the relationship between the cooling load and the vacuum degree, and increasing the target vacuum degree greater than 0.25 kPa; The "turbine 13-condenser 11-cold storage" coupling model is constructed to evaluate the influence of starting and stopping / regulating on the safety boundary of the generator 14; The exergy analysis and energy efficiency evaluation are performed: the exergy loss of the whole cold storage process is calculated from the "energy quality" angle, the bottleneck is identified, and the rationality of the technical route is demonstrated.

[0066] In this embodiment, the cooling tower 15, the circulating water pump 16, and the cooling pipeline 17 are also included, the condenser 11 is provided with a cooling water heat exchange pipe and a waste steam passage, and the circulating water pump 16 drives the cooling water to circulate between the cooling tower 15, the cooling pipeline 17, and the cooling water heat exchange pipe to reduce the temperature of the waste steam in the waste steam passage.

[0067] The standby technical solution can also use air cooling instead of the cooling tower 15 to cool the condensing water, and the air cooling is realized by using an air cooling island.

[0068] In this embodiment, the condensate pipeline 41, the shunt valve 5, the condensate pump 42, the variable frequency pump two 43, and the cold water pipeline 44 are also included. The waste steam of the condenser 11 becomes condensate water after passing through the shunt valve 5, part of the condensate water can enter the boiler 12 through the condensate pipeline 41 and the condensate pump 42, and the other part of the condensate water can enter the cold storage tank 2 through the cold water pipeline 44 and the variable frequency pump two 43 to further reduce the temperature to become low-temperature condensate water of 10-20℃, and the low-temperature condensate water can enter the condenser 11 again through the condensate water pipeline 45 to accelerate the condensation speed of the waste steam into water, improve the vacuum degree of the condenser 11, and further improve the power generation of the thermal power unit peak shaving system based on the cold and heat dual energy storage.

[0069] In this embodiment, the refrigeration machine 3 provides heat for the first heat exchanger 7 through the first exhaust pipe 31, and the first heat exchanger 7 provides heat for the heat storage tank 8; the heat storage tank 8 provides heat for the water flowing back to the boiler 12 through the second heat exchanger 9, and the circulating water pump 81 and the hot water pipeline 82 are arranged between the heat storage tank 8 and the second heat exchanger 9.

[0070] In this embodiment, the condensate water taking design is realized by the variable frequency pump two 43, the shunt valve 5, and the cold water pipeline 44. The backwater design is realized by the condensate water pipeline 45; the condensate water taking design and the backwater design together constitute the corresponding pipeline and pump for providing cold energy for the condenser 11. The water taking design and the backwater design do not affect the safe operation of the turbine 13 and the generator 14.

[0071] In this embodiment, a variable frequency pump one 21 and a cold storage pipeline 22 are further included. The variable frequency pump one 21 drives the refrigerant to store the cold energy generated by the refrigeration machine 3 in the cold storage tank 2 through the cold storage pipeline 22. The variable frequency pump one 21 and the cold storage pipeline 22 constitute a part of the cold storage pipeline.

[0072] In this embodiment, an atomizer is arranged in the condenser 11, and the low-temperature condensed water enters the condenser 11 in the form of atomized spray through the atomizer.

[0073] In this embodiment, the cold storage tank 2 is an open atmospheric steel tank, and a water distributor is arranged inside to realize temperature stratification, so as to ensure efficient storage and extraction of cold energy. The effective volume of the tank meets the cold release requirement for more than 1 hour in the peak period. The tank wall of the cold storage tank 2 is made of polyurethane foam insulation, and a floating top cover or a covering ball is arranged on the top to reduce evaporation loss and cold energy loss, so as to ensure that the temperature rise is not more than 1 ℃ within 24 hours.

[0074] In this embodiment, the variable frequency pump two 43 and the variable frequency pump one 21 are configured in one active and one standby or two active and one standby. The single pump flow is determined according to the designed cold energy, and the head is calculated according to the system resistance. The pump is equipped with a high-performance frequency converter to realize soft start and stop and accurate flow regulation.

[0075] In this embodiment, the cold storage tank 2 adopts temperature stratification design; the water distributor structure is arranged in the cold storage tank 2; the water distributor structure is provided with a stable temperature gradient layer maintaining structure, and the cold storage efficiency is greater than 95%; the temperature rise is less than 1 ℃ within 24 hours; The centrifuge part of the refrigeration machine 3 is optimized in COP under part load, and the valley electricity is efficiently stored. A complex pipe network hydraulic optimization model is established to optimize the pipe diameter / valve / connection point, avoid hydraulic imbalance, and ensure fault isolation. The whole adopts an intelligent predictive control strategy and algorithm optimization oriented to multi-objective optimization, and adopts a three-layer control architecture: day-ahead optimization (electricity price / weather / power generation plan) → real-time rolling (load fluctuation correction) → second-level closed loop (MPC pump / valve control). Cold energy and electricity price prediction: LSTM / Transformer predicts environmental temperature, unit load and electricity price, with an error of less than 5%. Intelligent operation and maintenance and fault diagnosis: data-driven early warning of refrigeration machine attenuation, pump vibration and scaling; a maintenance knowledge base is constructed to improve the availability.

[0076] In this embodiment, the vacuum degree of the condenser 11 is increased by more than 0.5 kPa in the process of providing cold energy for the condenser 11 by the cold storage tank 2 to accelerate the condensation of the exhaust steam into water.

[0077] According to specific needs, the condenser 11 is provided with cold energy by the cold storage tank 2 to accelerate the process of condensing the exhaust steam into water, and the vacuum degree of the condenser 11 can also be controlled at 0.25 kPa, 0.35 kPa, 0.40 kPa, 0.55 kPa, 0.65 kPa, 0.70 kPa or 0.75 kPa as needed.

[0078] Summary of the technical solutions of the present application An intelligent control system of a thermal power unit peak regulation system based on cold and heat dual energy storage, containing a condensate water recold system coupled with cold storage of a thermal power unit, the overall architecture of the system is composed of five core parts of a refrigeration device, a cold storage tank, a special frequency conversion pump set, a spraying device and an intelligent control system; part of the condensate water is extracted at the inlet of the condensate pump, a new condensate water cooling loop is built, and during the load low valley or electricity price low valley period, the condensate water is cooled by a refrigeration machine driven by low valley electricity, and stored in a large cold storage tank; during the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the form of atomized spraying through the frequency conversion pump set, the vacuum degree of the condenser is improved, and the power generation during the load peak or electricity price peak period is improved.

[0079] Preferably, the cold storage tank adopts temperature stratification design; a water distributor structure is arranged in the cold storage tank; the water distributor structure is provided with a stable temperature gradient layer maintaining structure, the cold storage efficiency is > 95%, and the 24h temperature rise is < 1℃; The centrifuge part of the refrigeration machine is optimized in COP under part load, and the valley electricity is efficiently stored; a complex pipe network hydraulic optimization model is established to optimize the pipe diameter / valve / connection point, avoid hydraulic imbalance, and ensure fault isolation; Preferably, the whole adopts an intelligent predictive control strategy and algorithm optimization oriented to multi-objective optimization, and adopts a three-layer control architecture: day-ahead optimization (electricity price / weather / power generation plan) → real-time rolling (load fluctuation correction) → second-level closed loop (MPC control pump / valve); Cold energy and electricity price prediction: LSTM / Transformer predicts environmental temperature, unit load and electricity price, with an error < 5%; Intelligent operation and maintenance and fault diagnosis: data-driven early warning of refrigeration machine attenuation, pump vibration and scaling; a maintenance knowledge base is built to improve the availability.

[0080] The core control strategy of the system is a fuzzy PID control based on constant temperature difference and demand prediction; the control target is to identify the cooling load change in real time, dynamically adjust the cold storage / cooling release condition, avoid main cycle disturbance and ensure system stability; The control system adopts a distributed control system or an intelligent control system based on PLC as a brain, and hardware cores include a PLC controller, a frequency converter, a temperature sensor, a pressure sensor, a flow sensor, and an electric actuator; the sensors are installed on the outlet of the refrigeration machine, the inlet and outlet of the cold storage tank, the inlet branch pipe of the condenser, and the main return water pipe, and real-time monitoring of temperature, pressure, flow, and other parameters is performed; The system network architecture is divided into a device layer, a control layer, and a monitoring layer. The device layer is composed of a frequency converter, a sensor, and an actuator, and is responsible for data acquisition and instruction execution; the control layer receives signals from the device layer by a PLC, executes a predetermined control logic, and outputs a frequency signal to control the water pump and the refrigeration machine; the monitoring layer is configured with a human-machine interface and a monitoring computer, is located in the power plant control room, provides a system panoramic view and a parameter setting interface for an operator, and can be connected to a main control system of the power plant to realize collaborative management.

[0081] The application relates to a thermal power unit peak regulation system based on cold and hot dual energy storage. A boiler generates high-temperature and high-pressure steam to drive a steam turbine to rotate, thereby driving a generator to generate power. The high-temperature and high-pressure steam becomes exhaust steam after passing through the steam turbine and enters a condenser to be condensed into water, thereby maintaining the vacuum degree in the condenser. The power generated by the generator is partially used to drive a refrigeration machine to refrigerate, and the refrigeration capacity is stored in a cold storage tank, thereby increasing the power generation capacity of the generator at the power peak and meeting the power demand at the power peak. The overall architecture of the control system is composed of five core parts, namely, a refrigeration device, a cold storage tank, a special variable frequency pump set, a spraying device, and an intelligent control system. The working process is as follows: part of the condensate water is extracted at the inlet of the condensate pump, a new condensate water cooling loop is established, the refrigeration machine is driven by low-valley electricity to cool the condensate water at the load low valley or electricity price low valley period, and the condensate water is stored in the large cold storage tank. At the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the atomizing spraying mode through the variable frequency pump set, the vacuum degree of the condenser is improved, and the power generation capacity is improved.

[0082] The scheme adds a refrigeration and cold storage system to the original generator set system, a pipeline for condensing water in the condenser is branched, and the cold storage system is used to provide cold energy to the condenser of the generator set to improve the condensing speed and thereby improve the power generation capacity and power generation speed. The overall architecture of the system is composed of five core parts, namely, a refrigeration device, a cold storage tank, a special variable frequency pump set, a spraying device, and an intelligent control system. The working process is as follows: part of the condensate water is extracted at the inlet of the condensate pump, a new condensate water cooling loop is established, the refrigeration machine is driven by low-valley electricity to cool the condensate water at the load low valley or electricity price low valley period, and the condensate water is stored in the large cold storage tank. At the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the atomizing spraying mode through the variable frequency pump set, the vacuum degree of the condenser is improved, and the power generation capacity is improved.

[0083] Key equipment is described as follows: Refrigeration device This scheme recommends using a voltage compression refrigeration machine, which has the advantages of mature technology, high refrigeration efficiency, and fast response speed, and is suitable for full-load operation during fixed valley electricity periods. The refrigeration capacity of a single refrigeration machine can be selected according to the unit capacity. The refrigeration machine should have a wide load adjustment capability (30%-100%) to adapt to the cold storage needs in different seasons and loads. The heat exchange medium is condensate water, and the system is provided with a perfect water treatment device to prevent fouling and corrosion. The overall COP design value of the refrigeration unit is not less than 4.0, and it can still maintain high operating efficiency at partial load.

[0084] Cold storage tank The cold storage tank is used to store low-temperature cooling water. This scheme recommends using an open-type atmospheric steel storage tank, which is internally provided with a water distributor to achieve temperature stratification and ensure efficient storage and extraction of cold energy. The effective volume of the storage tank should meet the 4-hour cold release requirement during peak periods. The tank wall should be insulated with polyurethane foam, and a floating top cover or a cover ball should be provided at the top to reduce evaporation loss and cold loss, ensuring that the temperature rise within 24 hours does not exceed 1°C.

[0085] Variable frequency pump set The variable frequency pump set adopts a one-to-one backup or two-to-one backup configuration. The single pump flow is determined according to the designed cold capacity, and the head is calculated according to the system resistance. The water pump is equipped with a high-performance frequency converter to realize soft start and stop and accurate flow regulation.

[0086] Spraying device The spraying device is a key component of the system, including a nozzle system, a distribution pipeline, a pressure regulating device, and a support structure. The nozzle is made of 316 stainless steel, with an atomizing angle of 90 degrees and a flow characteristic of solid cone spray. The nozzle arrangement density is 4-6 per m², uniformly distributed in the specified area of the condenser throat, ensuring that the spraying coverage rate reaches more than 85%. The system is provided with pressure regulating valves and flow meters to ensure balanced flow in each branch. The spraying system design pressure is 0.4-0.6 MPa, and the atomized particle size is controlled within the range of 100-300 μm, which ensures heat exchange effect and avoids erosion of the condenser tube bundle.

[0087] Control system The core control strategy of the system is fuzzy PID control based on constant temperature difference and demand prediction. The control objective is to identify cooling load changes in real time, dynamically adjust cold storage / cold release conditions, avoid main cycle disturbance, and ensure system stability.

[0088] The control system adopts a distributed control system or an intelligent control system based on PLC as the brain, and its hardware core includes PLC controllers, frequency converters, temperature sensors, pressure sensors, flow sensors, and electric actuators. The sensors are installed at the outlet of the refrigeration machine, the inlet and outlet of the cold storage tank, the condensate water inlet branch pipe, and the main return water pipeline to monitor temperature, pressure, flow, and other parameters in real time.

[0089] The system network architecture is divided into a device layer, a control layer, and a monitoring layer. The device layer is composed of frequency converters, sensors, and actuators, responsible for data acquisition and instruction execution. The control layer receives signals from the device layer through PLC, executes predetermined control logic, and outputs frequency signals to control the water pump and refrigeration machine. The monitoring layer is configured with a human-machine interface and a monitoring computer, located in the power plant control room, providing operators with a panoramic view of the system and parameter setting interfaces, and can be connected to the main control system of the power plant for collaborative management.

[0090] Project innovation points 1. System integration innovation This project first integrates large-scale temperature stratified water storage technology into the condensate water system of a water-cooled thermal power unit in the form of direct spray heat exchange. Unlike traditional retrofit solutions, this system is not a simple "patch" but a new "cold-electricity" combined production system that operates in coordination with the main system. Through innovative condensate water extraction and return water design, the system achieves efficient storage and utilization of cold energy without affecting the safety of the main system, creating a new paradigm for energy time shifting using auxiliary systems of thermal power units.

[0091] 2. Control strategy innovation The system breaks through the simple control logic of traditional storage systems based on temperature settings and develops an intelligent predictive control system that integrates "cold energy demand prediction, power market signals, and plant-level economic optimization." This system transforms the storage device from a passive cooling device into an active "virtual energy asset" that can actively participate in plant economic dispatch and make intelligent decisions about the best operating mode, achieving a leap from "controlling temperature" to "managing energy."

[0092] 3. Cross-border innovation in technology application This project is not the invention of a single technology, but the cross-disciplinary and deep re-creation of the integration of mature building storage technology, industrial frequency conversion technology, and large container manufacturing technology with complex thermal power systems. In view of the special environment of thermal power plants (such as vibration, safety level, and operation cycle), a series of engineering problems such as large-flow hydraulic distribution, system safety isolation, and long-term reliability of equipment are solved, forming a storage technology solution specifically for thermal power scenarios.

[0093] Advantages compared with molten salt thermal storage: 1. Mature technology, high reliability Water storage uses conventional refrigerators, water pumps, cold storage tanks and spray devices, which are very mature general-purpose equipment in the industrial field, with low technical risk and stable operation; molten salt thermal storage system is complex, involving high-temperature molten salt pump, electric heating, anti-freezing, anti-corrosion and other special technologies and materials, with high operation and maintenance requirements and relatively large failure risk.

[0094] 2. Low initial investment cost Water storage has low estimated investment, and the cost of core equipment (such as water tank and refrigerator) is relatively controllable; the initial investment of molten salt thermal storage is high, usually hundreds of millions to hundreds of millions of yuan, which is several times higher than that of water storage.

[0095] 3. Obvious safety advantage Water storage medium is water, which is non-toxic, non-flammable and has no high pressure risk, and the system works at normal or low temperature, with very low safety risk; the medium of molten salt thermal storage is high-temperature molten salt (usually above 300°C), which has the risk of scalding, corrosion and freezing, and requires high insulation, monitoring and safety protection for the system.

[0096] 4. Fast system response and flexible operation Water storage responds quickly to temperature changes, and the refrigerator and pump group can be started and stopped quickly, which is very suitable for frequent and rapid peak shaving within a day (such as 4-6 hours); molten salt thermal storage has slow start-up and preheating, large thermal inertia, and is not suitable for frequent start-stop and rapid load change, but is more suitable for long-term and stable energy output.

[0097] 5. Completely isolated from the main unit, without affecting the safety of the main unit Water storage is coupled with the main system through an independent condensate water circuit and is an independent auxiliary system, which can be immediately removed from operation even if the storage system fails, without affecting the safety of the boiler, turbine and other main units. The system is provided with double isolation valves to ensure that the main unit will not be affected under any operating conditions. Molten salt thermal storage usually needs to be directly coupled with the thermal system (such as steam and feed water) of the unit, which is complex to modify, and may directly affect the normal operation of the main unit if the system fails.

[0098] 6. Simple operation and low cost Water storage operation and maintenance personnel are familiar with conventional water systems, and daily maintenance work is simple, with strong general-purpose spare parts; molten salt thermal storage requires special operation and maintenance knowledge and skills to deal with molten salt freezing, corrosion and pump valve sealing problems, with higher operation and maintenance cost and professional requirements.

[0099] 7. Suitable for "small investment, fast return" modification of existing thermal power units Water storage is very focused on the goal of taking advantage of the peak-valley electricity price difference to increase power generation during peak hours by reducing circulating water temperature to increase vacuum, which does not change the core thermal cycle and is a typical "marginal benefit" modification project with short investment recovery period; molten salt heat storage is usually used for more complex "thermal decoupling" or "deep peak shaving" modification involving deep integration of main units, complex system and long investment recovery period.

[0100] Project investment The project investment amount changes according to the target value Taking a 300 MW subcritical unit as an example 1. Design parameters Parameter Value Source / Explanation Unit Unit Unit Unit 38% Unit Unit 40°C Unit Unit Unit Unit Unit Unit Unit Unit 14°C Unit Unit 5 h Unit Unit 4 h Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Unit Project income (1) Electricity accounting Refrigerator power consumption: <3 MWh Variable frequency pump set power consumption: <1 MWh Due to the condenser vacuum increase, the unit generates more power: >7 MWh Therefore: there is electricity income.

[0101] The present application relates to a kind of based on cold and hot dual energy storage thermal power unit peak shaving system and method, including boiler, steam turbine, generator, condenser, refrigerator, cold storage tank and heat storage tank;During load low valley or electricity price low valley period, part of electricity generated by generator drives refrigerator refrigeration, and cold storage tank is stored cold, and the heat generated in the working process of refrigerator is stored by heat storage;The overall architecture of control system is composed of five core parts of refrigeration device, cold storage tank and heat storage tank, pump set, spraying device and intelligent control system;During load peak or electricity price peak period, part of condensate is extracted at condensate pump inlet, new condensate cooling circuit is built, and this part of condensate is cooled using cold storage tank, and the heat of heat storage tank is used to heat the condensate to be returned to boiler, and low-temperature condensate is injected into condenser in atomizing spray mode by variable frequency pump set, to improve the vacuum degree of condenser, thereby improving power generation power.

[0102] The above describes the technical solutions provided by the embodiments of the present application in detail, and the principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method and core idea of the present application. For those skilled in the art, according to the idea of the present application, the specific implementation mode and application range can be changed, and the present specification should not be understood as limiting the present application.

Claims

1. A thermal power unit peak shaving system based on cold and hot dual energy storage, comprising a condenser (11), a boiler (12), a steam turbine (13) and a generator (14), characterized in that, It also includes a cold storage tank (2), a refrigerator (3), a first heat exchanger (7), a heat storage tank (8) and a second heat exchanger (9), the boiler (12) is heated by coal, gas, oil or electricity to generate high-temperature and high-pressure steam, the high-temperature and high-pressure steam drives the steam turbine (13) to rotate, the steam turbine (13) drives the generator (14) to generate electricity when rotating, the high-temperature and high-pressure steam becomes exhaust steam after passing through the steam turbine (13) and enters the condenser (11) to be condensed into water, maintaining the vacuum degree in the condenser (11); When the electricity consumption is at the valley, part of the electricity generated by the generator (14) drives the refrigerator (3) to refrigerate, and the cold energy is stored through the cold storage tank (2) and the heat storage tank (8) through the first heat exchanger (7); When the electricity consumption is at the peak, the cold energy stored in the cold storage tank (2) provides cold energy for the condenser (11), accelerates the speed of the exhaust steam in the condenser (11) to condense into water, and further improves the vacuum degree in the condenser (11); the heat energy stored in the heat storage tank (8) provides heat energy for the water flowing back to the boiler (12) through the second heat exchanger (9), accelerates the vaporization speed and heating temperature of the water in the boiler (12), thereby improving the power generation of the generator (14) at the electricity consumption peak.

2. The system for peak load regulation of a thermal power unit according to claim 1, characterized in that By modeling the condenser (11) under variable conditions, a heat transfer model is established to quantify the relationship between cooling load and vacuum degree, and the target is to improve the vacuum degree to more than 0.25kPa; A "steam turbine (13)-condenser (11)-cold storage and heat storage" coupling model is constructed to evaluate the influence of start-stop / regulation on the safety boundary of the generator (14); Performing exergy analysis and energy efficiency evaluation: calculate the exergy loss of the whole process of cold storage and heat storage from the "energy quality" angle, identify the bottleneck, and demonstrate the rationality of the technical route.

3. The system for peak load regulation of a thermal power unit according to claim 1, characterized in that, It also includes a condensate pipeline (41), a flow dividing valve (5), a condensate pump (42), a variable frequency pump two (43) and a cold taking pipeline (44); The exhaust steam of the condenser (11) becomes condensate water after passing through the flow dividing valve (5), part of the condensate water can enter the boiler (12) through the condensate pipeline (41) and the condensate pump (42), and the other part of the condensate water can enter the cold storage tank (2) through the cold taking pipeline (44) and the variable frequency pump two (43) to further reduce the temperature to become low-temperature condensate water of 10-20℃, and the low-temperature condensate water can enter the condenser (11) again through the condensate water pipeline (45) to accelerate the speed of the exhaust steam condensing into water, improve the vacuum degree of the condenser (11), and further improve the power generation of the thermal power unit peak regulation system based on cold and heat dual energy storage.

4. The system for peak load regulation of a thermal power unit according to claim 3, characterized in that, The refrigerator (3) provides heat for the first heat exchanger (7) through the first exhaust pipe (31), and the first heat exchanger (7) provides heat for the heat storage tank (8); The heat storage tank (8) provides heat for the water flowing back to the boiler (12) through the second heat exchanger (9), and a circulating water pump (81) and a hot water pipeline (82) are arranged between the heat storage tank (8) and the second heat exchanger (9).

5. The system for peak load regulation of a thermal power unit according to claim 4, characterized in that Further comprising a variable frequency pump one (21), a cold storage pipeline (22), the variable frequency pump one (21) drives the cold energy generated by the refrigeration machine (3) to be stored in the cold storage tank (2) through the cold storage pipeline (22); The condenser (11) is provided with an atomizer, and the low-temperature condensed water enters the condenser (11) in the form of atomized spray through the atomizer.

6. The system for peak load regulation of a thermal power unit according to claim 5, characterized in that The cold storage tank (2) is an open atmospheric steel storage tank, which is internally provided with a water distributor to realize temperature stratification, so as to ensure efficient storage and extraction of cold energy; The effective volume of the storage tank meets the cold release requirement for more than 1 hour in the peak period; The tank wall of the cold storage tank (2) is provided with polyurethane foam insulation, and a floating top cover or a covering ball is arranged at the top to reduce evaporation loss and cold energy loss, so that the temperature rise within 24 hours is not more than 1 DEG C.

7. The system for peak load regulation of a thermal power unit according to claim 6, characterized in that The variable frequency pump two (43) and the variable frequency pump one (21) are configured in one-to-one or two-to-one, the single pump flow is determined according to the designed cold energy, and the lift is calculated according to the system resistance. The water pump is provided with a high-performance frequency converter to realize soft start and stop and accurate flow regulation.

8. A method for peak shaving of a thermal power unit based on cold and hot dual energy storage, characterized in that, The system includes a condensate water recooling system coupled with a thermal storage of a thermal power unit and a boiler backflow water heating system, and the overall architecture of the system is composed of five core parts, i.e., a refrigeration device, a cold storage tank and a heat storage tank, a special variable frequency pump group, a spraying device and an intelligent control system; A part of the condensate water is extracted at the inlet of the condensate water pump, a new condensate water cooling loop is built, and in the load valley or electricity price valley period, the condensate water is cooled by the refrigeration machine driven by the valley electricity and stored in the large cold storage tank; A second heat exchanger is arranged at the outlet of the condensate water pump to build a heating structure of the condensate water backflow loop, and in the load valley or electricity price valley period, the heat generated by the refrigeration machine is stored in the large heat storage tank through the first heat exchanger, and the heat storage tank can heat the condensate water in the condensate water backflow loop through the second heat exchanger, so as to increase the temperature of the condensate water entering the boiler; In the load peak or electricity price peak period, the low-temperature condensate water is injected into the condenser in the form of atomized spray through the variable frequency pump group, the vacuum degree of the condenser is improved, and the condensate water backflowing into the boiler is heated through the second heat exchanger, so as to improve the power generation capacity in the load peak or electricity price peak period.

9. The method of claim 8, wherein, The cold storage tank (2) is designed with temperature stratification; The cold storage tank (2) is provided with a water distributor structure; The water distributor structure is provided with a stable temperature gradient maintaining structure, the cold storage efficiency is greater than 95%, and the temperature rise in 24 hours is less than 1 DEG C. The centrifugal machine of the refrigeration machine (3) is optimized in partial load COP, and the valley electricity is efficiently stored; A complex pipe network hydraulic optimization model is established to optimize the pipe diameter / valve / connection point, avoid hydraulic imbalance, and ensure fault isolation.

10. The thermal power unit peak shaving method of claim 9, which adopts an intelligent predictive control strategy and algorithm optimization for multi-objective optimization, and adopts a three-layer control architecture: day-ahead optimization (electricity price / weather / power generation plan)→real-time rolling (load fluctuation correction)→second-level closed loop (MPC pump / valve control); Cold energy and electricity price prediction: LSTM / Transformer predicts environmental temperature, unit load and electricity price with an error of less than 5%. Intelligent operation and fault diagnosis: data-driven early warning of chiller degradation, pump vibration, and fouling; build operation knowledge base to improve availability; The core control strategy of the system is fuzzy PID control based on temperature difference constant and demand prediction; the control objective is to identify cooling load changes in real time, dynamically adjust the charging / discharging conditions, avoid main cycle disturbance, and ensure system stability; The control system uses a distributed control system or an intelligent control system based on PLC as the brain, and the hardware core includes PLC controllers, frequency converters, temperature sensors, pressure sensors, flow sensors, and electric actuators; sensors should be installed at the chiller outlet, cold storage tank inlet and outlet, condenser inlet branch pipe, and main return water pipeline to monitor temperature, pressure, flow, and other parameters in real time; The system network architecture is divided into device layer, control layer, and monitoring layer. The device layer consists of frequency converters, sensors, and actuators, responsible for data acquisition and instruction execution; The control layer receives signals from the device layer through PLC, executes the predetermined control logic, and outputs frequency signals to control the water pump and chiller; the monitoring layer configures the human-machine interface and monitoring computer, located in the power plant control room, provides system panoramic view and parameter setting interface for operators, and can access the main control system of the power plant for collaborative management.

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