Light energy-electric energy-chemical energy coupling coal-fired unit system and operation method

Abstract

The invention provides a light energy-electric energy-chemical energy coupling coal-fired unit system and an operation system. The system comprises a coal-fired power generation subsystem, a photovoltaic-thermochemistry subsystem and a Kalina circulation subsystem. The coal-fired power generation subsystem is connected with the photovoltaic-thermochemistry subsystem, and the photovoltaic-thermochemistry subsystem is connected with the Kalina circulation subsystem; the coal-fired power generation subsystem is used for basic power generation and peak regulation of the whole system; the photovoltaic-thermochemistry subsystem is used for converting solar energy into electric energy through a photovoltaic device and driving a reversible thermochemistry device based on a calcium-based compound by using the electric energy, so that conversion and storage of electric energy-heat energy-chemical energy are realized; the Kalina circulation subsystem is used for waste heat utilization of thermal chemical reaction products. The heat storage / release temperature is matched with the coal-fired system through thermochemical reaction pressure regulation and control, dynamic regulation of the Kalina cycle working medium concentration is combined, the irreversible loss of heat transfer is remarkably reduced, and the comprehensive energy utilization efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of coal-fired power generation, energy storage technology and waste heat recovery technology, specifically relating to a coal-fired unit system and operation method that couples solar energy, electrical energy and chemical energy. Background Technology

[0002] With the continuous growth of demand for renewable energy consumption in new power systems, coal-fired power units urgently need to improve their deep peak-shaving capabilities and dynamic load response characteristics. Traditional solar-coal complementary technologies are limited by photovoltaic volatility, rigid coupling of solar thermal systems, thermal storage temperature ranges, and geographical conditions, making flexible peak-shaving and cross-period energy dispatch difficult. The rigid coupling between traditional solar thermal systems and coal-fired units lacks flexibility and cannot adapt to dynamic load changes. Existing thermal storage technologies have limited temperature ranges and are constrained by geographical conditions, making cross-period energy dispatch and efficient storage difficult. Coal-fired power units in new power systems need to improve their deep peak-shaving capabilities and rapid load response characteristics to support a high proportion of renewable energy integration. Traditional waste heat power generation systems (such as the Rankine cycle) have poor adaptability to wide-temperature-range heat sources, suffer from large irreversible heat transfer losses, and have low energy utilization efficiency.

[0003] To address the aforementioned issues, it is necessary to propose a rationally designed and effective coal-fired power unit system and operation method that couples solar energy, electrical energy, and chemical energy. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a coal-fired power unit system and operation method that couples light energy, electrical energy and chemical energy.

[0005] One aspect of the present invention provides a coal-fired power unit system that couples light energy, electrical energy, and chemical energy, including a coal-fired power generation system, a photovoltaic-thermochemical subsystem, and a Karina cycle subsystem;

[0006] The coal-fired power generation system is connected to the photovoltaic-thermochemical subsystem, and the photovoltaic-thermochemical subsystem is connected to the Karina cycle subsystem; wherein...

[0007] The coal-fired power generation system is used for basic power generation and peak shaving of the entire system.

[0008] The photovoltaic-thermochemical subsystem is used to convert solar energy into electrical energy through a photovoltaic device, and to use the electrical energy to drive a reversible thermochemical device based on calcium-based compounds, thereby realizing the conversion and storage of electrical energy, thermal energy and chemical energy.

[0009] The Karina cycle subsystem is used for the utilization of waste heat from thermochemical reaction products.

[0010] Optionally, the photovoltaic-thermochemical subsystem includes the photovoltaic device, the thermochemical device, and the heat exchanger device;

[0011] The photovoltaic device includes a photovoltaic-driven electric heater; the thermochemical device includes a dehydration reactor;

[0012] The coal-fired power generation system includes a filter and a low-pressure turbine cylinder connected to the filter;

[0013] The first inlet of the dehydration reactor is connected to the electric heater, and the first outlet of the dehydration reactor is connected to the steam injection port of the low-pressure cylinder of the steam turbine through the filter; wherein...

[0014] The electric heater drives the decomposition of calcium hydroxide in the dehydration reactor, realizing the conversion of electrical energy into thermal energy into chemical energy. The steam generated by the reaction is connected to the steam injection port of the low-pressure cylinder of the steam turbine through the filter.

[0015] Optionally, the heat exchanger unit includes a feedwater preheater; the Karina circulation subsystem includes an evaporator; and the thermochemical unit further includes a calcium oxide storage tank.

[0016] The first inlet of the feedwater preheater is connected to the second outlet of the dewatering reactor, and the first outlet of the feedwater preheater is connected to the first inlet of the evaporator.

[0017] The inlet of the calcium oxide storage tank is connected to the first outlet of the evaporator; wherein,

[0018] The calcium oxide produced by the dehydration reactor is sent to the water preheater to release heat. The released calcium oxide is then sent to the evaporator to further release heat to drive the Karina cycle. After the heat is released again, the calcium oxide is sent to the calcium oxide storage tank for storage.

[0019] Optionally, the thermochemical apparatus further includes a hydration reactor and a calcium hydroxide storage tank; the coal-fired power generation system further includes a low-pressure turbine cylinder and a throttle valve;

[0020] The first outlet of the calcium oxide storage tank is connected to the first inlet of the hydration reactor.

[0021] The low-pressure cylinder of the steam turbine is connected to the second inlet of the hydration reactor via the throttle valve;

[0022] The first outlet of the evaporator is connected to the inlet of the calcium hydroxide storage tank, and the outlet of the calcium hydroxide storage tank is connected to the dehydration reactor.

[0023] Optionally, the coal-fired power generation system further includes a high-pressure heater, a boiler, and a high-pressure turbine cylinder;

[0024] The outlet and inlet of the feedwater preheater are respectively connected to the high-pressure heater and the boiler;

[0025] The inlet of the hydration reactor is connected to both the boiler and the high-pressure cylinder of the steam turbine.

[0026] Optionally, the dehydration reactor and the hydration reactor operate at atmospheric pressure in a temperature range of 490℃~540℃.

[0027] The temperature range of the calcium-based material after it flows out of the feedwater preheater and before it enters the evaporator is 260℃~310℃.

[0028] Optionally, the Karina cycle subsystem further includes a separator and a first regenerator;

[0029] The inlet of the separator is connected to the second outlet of the evaporator, the first outlet of the separator is connected to the first inlet of the first regenerator, and the first outlet of the first regenerator is connected to the second inlet of the evaporator.

[0030] Optionally, the Karina cycle subsystem further includes a turbine, a mixer, a pressure relief valve, and a second regenerator;

[0031] The turbine inlet is connected to the second outlet of the separator, and the turbine outlet is connected to the mixer;

[0032] The pressure relief valve is connected to the first regenerator and the mixer, respectively;

[0033] The first inlet of the second regenerator is connected to the outlet of the mixer, and the first outlet of the second regenerator is connected to the second inlet of the first regenerator.

[0034] Optionally, the Karina circulation subsystem also includes a pump and a condenser;

[0035] The inlet of the condenser is connected to the second outlet of the second regenerator, the outlet of the condenser is connected to the inlet of the pump, and the outlet of the pump is connected to the second inlet of the second regenerator.

[0036] Another aspect of the present invention provides an operation method for a coal-fired power unit system coupling solar energy, electrical energy, and chemical energy, for use in the aforementioned coal-fired power unit system coupling solar energy, electrical energy, and chemical energy; the operation method includes:

[0037] During periods of sufficient sunlight, the photovoltaic devices in the photovoltaic-thermochemical subsystem generate electricity, part of which is transmitted to the grid, and the remaining electricity drives the thermochemical reaction for heat storage. The coal-fired power generation system reduces its own load, and the Karina cycle subsystem realizes the utilization of sensible heat and waste heat from the thermochemical reaction products.

[0038] When sunlight is insufficient, the photovoltaic-thermochemical subsystem terminates photovoltaic power generation and performs thermochemical reactions to release heat, assisting the coal-fired unit to increase its load, making up for the photovoltaic shortfall, and maintaining a constant total output. The Karina cycle realizes the utilization of sensible heat and waste heat from the thermochemical reaction products.

[0039] This invention relates to a coal-fired power unit system and its operation method that couples solar, electrical, and chemical energy. The system deeply couples a coal-fired power generation system, a photovoltaic-thermochemical subsystem, and a Karina cycle subsystem to construct an energy conversion architecture that features decoupled synergy between solar and coal, cross-period scheduling of chemical energy, and multi-stage waste heat recovery. The coal-fired power generation system achieves flexible output adjustment through steam injection and extraction; the photovoltaic-thermochemical subsystem employs calcium-based thermochemical thermal storage technology, using a fluidized bed reactor as its core to achieve efficient conversion and cross-temporal storage of solar, electrical, and chemical energy; the Karina cycle subsystem uses ammonia water as the working fluid, utilizing its non-azeotropic properties to achieve temperature glide matching and efficient recovery of the sensible heat of thermochemical reaction products. Through a dynamic operation strategy driven by sunlight conditions, the system achieves synergistic optimization of photovoltaic fluctuation mitigation, enhanced coal peak-shaving capacity, and deep utilization of waste heat under all operating conditions, significantly improving the overall energy efficiency and the economic benefits of solar-coal complementarity. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a coal-fired power unit system that couples light energy, electrical energy, and chemical energy according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic flowchart illustrating the operation method of a coal-fired power unit system that couples light energy, electrical energy, and chemical energy, according to another embodiment of the present invention. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] like Figure 1 As shown, one aspect of the present invention provides a coal-fired power unit system that couples light energy, electrical energy, and chemical energy, including a coal-fired power generation system, a photovoltaic-thermal chemical subsystem, and a Karina cycle subsystem.

[0044] The coal-fired power generation system is connected to the photovoltaic-thermochemical subsystem, and the photovoltaic-thermochemical subsystem is connected to the Karina cycle subsystem.

[0045] The coal-fired power generation system is used for basic power generation and peak shaving of the entire system.

[0046] The photovoltaic-thermochemical subsystem is used to convert solar energy into electrical energy through a photovoltaic device, and to use the electrical energy to drive a reversible thermochemical device based on calcium-based compounds, thereby realizing the conversion and storage of electrical energy, thermal energy and chemical energy.

[0047] The Karina cycle subsystem is used for the utilization of waste heat from thermochemical reaction products.

[0048] Specifically, when there is sufficient sunlight, some of the photovoltaic power is directly fed into the grid, and the remainder drives thermochemical reactions for heat storage, while the coal-fired power units reduce their load. The Karina cycle realizes the utilization of sensible and waste heat from the thermochemical reaction products. When there is insufficient sunlight, the heat released by the thermochemical reaction assists the coal-fired power units in increasing their load, making up for the photovoltaic shortfall and maintaining a constant total output. The Karina cycle realizes the utilization of sensible and waste heat from the thermochemical reaction products.

[0049] Thermochemical thermal energy storage technology converts solar energy into high-density chemical energy storage through reversible reactions. Its wide temperature range characteristics allow for dynamic matching with steam parameters in coal-fired systems, overcoming the spatiotemporal constraints of solar-coal synergy. Meanwhile, the Karina cycle, leveraging the temperature glide characteristics of its non-azeotropic working fluid, adaptively recovers the waste heat from the thermochemical reaction over a wide temperature range, compensating for the low efficiency of traditional waste heat power generation. The synergy of these two technologies provides a complete solution for solar-coal complementary systems, encompassing thermal energy storage, peak shaving, and waste heat recovery, offering the dual advantages of high-efficiency energy conversion and operational flexibility.

[0050] This invention relates to a coal-fired power unit system that couples solar, electrical, and chemical energy. Through deep coupling of a coal-fired power generation system, a photovoltaic-thermochemical subsystem, and a Karina cycle subsystem, it constructs an energy conversion architecture characterized by decoupled synergy between solar and coal, cross-period scheduling of chemical energy, and multi-stage waste heat recovery. The coal-fired power generation system achieves flexible output adjustment through steam injection and extraction; the photovoltaic-thermochemical subsystem employs calcium-based thermochemical thermal storage technology, using a fluidized bed reactor as its core to achieve efficient conversion and cross-temporal storage of solar, electrical, and chemical energy; the Karina cycle subsystem uses ammonia as the working fluid, leveraging its non-azeotropic properties to achieve temperature glide matching and efficient recovery of the sensible heat from thermochemical reaction products. Through a dynamic operation strategy driven by illumination conditions, it achieves synergistic optimization of photovoltaic fluctuation mitigation, enhanced coal peak-shaving capacity, and deep utilization of waste heat under all operating conditions, significantly improving the system's overall energy efficiency and the economic viability of solar-coal complementarity.

[0051] For example, such as Figure 1 As shown, the coal-fired power generation system includes a boiler 101, a high-pressure cylinder 102 of a steam turbine, an intermediate-pressure cylinder 103 of a steam turbine, a low-pressure cylinder 104 of a steam turbine, a generator 105, a condenser 106, a condensate pump 107, a low-pressure heater 108, a deaerator 109, a feedwater pump 110, a high-pressure heater 111, a filter 112, and a throttle valve 113.

[0052] As shown in the figure, the photovoltaic-thermochemical subsystem includes a photovoltaic device, a thermochemical device, and a heat exchanger device. The photovoltaic device includes a photovoltaic-driven electric heater 202; the thermochemical device includes a dehydration reactor 201, a hydration reactor 204, a calcium oxide storage tank 205, and a calcium hydroxide storage tank 206; the heat exchanger device includes a feedwater preheater 203. The photovoltaic-thermochemical subsystem may employ a fluidized bed reactor.

[0053] The Karina subsystem includes power equipment, heat exchangers, and auxiliary equipment. The power equipment includes turbine 304 and pump 309. The heat exchangers include evaporator 301, condenser 308, first regenerator 302, and second regenerator 307. The auxiliary equipment includes separator 303, pressure relief valve 305, and mixer 306. The non-azeotropic working fluid used in the Karina subsystem is ammonia water.

[0054] The main steam outlet of boiler 101 is connected to the inlet of high-pressure cylinder 102 of turbine, the reheat steam outlet of boiler 101 is connected to the inlet of intermediate-pressure cylinder 103 of turbine, and the outlet of intermediate-pressure cylinder 103 is connected to the inlet of low-pressure cylinder 104 of turbine. Low-pressure cylinder 104 is equipped with a steam inlet; a dehydration reaction bed 201 is connected to the steam inlet via a filter 112. Low-pressure cylinder 104 is connected to generator 105. High-pressure cylinder 102, intermediate-pressure cylinder 103, and low-pressure cylinder 104 are connected via a drive shaft, jointly driving generator 105 to output electrical power. The outlet of low-pressure cylinder 104 is successively connected to low-pressure heater 108 via condenser 106 and condensate pump 107. Steam extracted from low-pressure cylinder 104 is transported to low-pressure heater 108, and the extraction pipeline is equipped with a branch line. The steam extracted from the low-pressure cylinder is connected to the hydration reactor 205 via the throttle valve 113, and the feedwater from the outlet of the low-pressure heater 108 is delivered to the deaerator 109. The steam extracted from the intermediate-pressure cylinder 103 of the turbine is successively delivered to the high-pressure heater 111 via the deaerator 109 and the feedwater pump 110. The steam extracted from the high-pressure cylinder 102 of the turbine is also delivered to the high-pressure heater 111. The high-pressure heater 111 is connected to the feedwater inlet of the boiler 101. The feedwater pipeline is equipped with a diversion point and a preheating feedwater junction point. The diverted feedwater is connected to the feedwater preheater 204 and then flows back to the preheating feedwater junction point. The outlet of the high-pressure cylinder 102 of the turbine is connected to the boiler 101. The cold reheat steam pipeline is equipped with a diversion point and a preheating reheat steam junction point. The diverted cold reheat steam is connected to the reheat steam preheater 203 and then flows back to the preheating reheat steam junction point.

[0055] For example, the first inlet of the dehydration reactor 201 is connected to the electric heater 202, and the first outlet of the dehydration reactor 201 is connected to the steam injection port of the low-pressure cylinder 105 of the steam turbine through the filter 112.

[0056] The electric heater 202 drives the decomposition of calcium hydroxide in the dehydration reactor 201, realizing the conversion of electrical energy to thermal energy to chemical energy. The water vapor generated by the reaction is connected to the steam injection port of the low-pressure cylinder 105 of the steam turbine through the filter 112.

[0057] For example, such as Figure 1 As shown, the first inlet of the water preheater 203 is connected to the second outlet of the dewatering reactor 201, and the first outlet of the water preheater 203 is connected to the first inlet of the evaporator 301; the inlet of the calcium oxide storage tank 205 is connected to the first outlet of the evaporator 301.

[0058] The calcium oxide produced by the dehydration reactor 201 is transported to the water preheater 203 for heat release. The calcium oxide after heat release is transported to the evaporator 301 for further heat release to drive the Karina cycle. The calcium oxide after heat release is then transported to the calcium oxide storage tank 205 for storage.

[0059] For example, the first outlet of the calcium oxide storage tank 205 is connected to the first inlet of the hydration reactor 204; the low-pressure cylinder 104 of the steam turbine is connected to the second inlet of the hydration reactor 204 through the throttle valve 113; the first outlet of the evaporator 301 is connected to the inlet of the calcium hydroxide storage tank 206, and the outlet of the calcium hydroxide storage tank 206 is connected to the dehydration reactor 201.

[0060] Among them, the calcium oxide storage tank 205 is connected to the hydration reactor 204. The steam extracted from the low-pressure cylinder 104 of the steam turbine is connected to the hydration reactor 204 through the throttle valve 113. The cold reheat steam is connected to the hydration reactor 204 to absorb the heat of calcium oxide hydration reaction, and then flows back to the preheating reheat steam junction point. The calcium hydroxide produced by the reaction is connected to the feedwater preheater 203 to release heat, and then connected to the evaporator 301 to further release heat to drive the Karina cycle, and finally connected to the calcium hydroxide storage tank 206.

[0061] For example, such as Figure 1 As shown, the outlet and inlet of the feedwater preheater 203 are connected to the high-pressure heater 111 and the boiler 101, respectively; the inlet of the hydration reactor 204 is connected to the boiler 101 and the high-pressure cylinder 102 of the steam turbine, respectively.

[0062] The high-pressure heater 111 is connected to the feedwater inlet of the boiler 101. The feedwater pipeline is equipped with a diversion point and a preheating feedwater junction point. The diverted feedwater is connected to the feedwater preheater 203 and then flows back to the preheating feedwater junction point. The outlet of the turbine high-pressure cylinder 102 is connected to the boiler 101. The cold reheat steam pipeline is equipped with a diversion point and a preheating reheat steam junction point. The diverted cold reheat steam is connected to the feedwater preheater 203 and then flows back to the preheating reheat steam junction point.

[0063] For example, the dehydration reactor 201 and the hydration reactor 204 operate at atmospheric pressure in a temperature range of 490°C to 540°C; the temperature range of the calcium-based material after it flows out of the feed water preheater 203 and before it enters the evaporator 301 is 260°C to 310°C.

[0064] For example, such as Figure 1 As shown, the inlet of the separator 303 is connected to the second outlet of the evaporator 301, the first outlet of the separator 303 is connected to the first inlet of the first regenerator 302, and the first outlet of the first regenerator 302 is connected to the second inlet of the evaporator 301.

[0065] The inlet of turbine 304 is connected to the second outlet of separator 303, and the outlet of turbine 304 is connected to mixer 306; the pressure relief valve 305 is connected to the first regenerator 302 and mixer 306 respectively; the first inlet of the second regenerator 307 is connected to the outlet of mixer 306, and the first outlet of the second regenerator 307 is connected to the second inlet of the first regenerator 302.

[0066] The inlet of the condenser 308 is connected to the second outlet of the second regenerator 307, the outlet of the condenser 308 is connected to the inlet of the pump 309, and the outlet of the pump 309 is connected to the second inlet of the second regenerator 307.

[0067] Specifically, the Karina circulating working fluid absorbs heat from the thermochemical calcium-based material in the evaporator 301 to a gas-liquid mixed state, and then connects to the separator 303. The steam is connected to the turbine 304, the solution is connected to the first regenerator 302 and the pressure relief valve 305, and then they converge in the mixer 306. Subsequently, they are connected to the second regenerator 307 and the condenser 308, and finally enter the pump 309 to increase the pressure.

[0068] like Figure 2 As shown, another aspect of the present invention provides an operation method S100 for a coal-fired power unit system that couples solar energy, electrical energy, and chemical energy, for use in the aforementioned coal-fired power unit system that couples solar energy, electrical energy, and chemical energy; the specific structural features of this coal-fired power unit system that couples solar energy, electrical energy, and chemical energy have been described in detail above and will not be repeated here.

[0069] The operation method S100 of the coal-fired power unit system coupled with solar energy, electrical energy, and chemical energy includes:

[0070] S110. During periods of sufficient sunlight, the photovoltaic device in the photovoltaic-thermochemical subsystem generates electricity. Part of the electricity is transmitted to the grid, and the remaining electricity drives the thermochemical reaction for heat storage. The coal-fired power generation system reduces its own load, and the Karina cycle subsystem realizes the utilization of the sensible heat and waste heat of the thermochemical reaction products.

[0071] Specifically, during periods of ample sunlight:

[0072] In the coal-fired power generation system, the steam injection port of the low-pressure cylinder 104 of the steam turbine is open, the steam extraction pipe diversion point of the low-pressure cylinder 104 of the steam turbine is closed, the filter 112 is working, and the throttle valve 113 is not working; in the photovoltaic-thermochemical subsystem, the hydration reaction bed 204 is not working, and all other photovoltaic devices, thermochemical devices, and heat exchanger devices are working normally; all devices in the Karina cycle subsystem are working normally.

[0073] The photovoltaic-driven electric heater 202 operates, heating the dehydration reactor 201. Calcium hydroxide particles from the calcium hydroxide storage tank 206 enter the dehydration reactor 201 and decompose. The gaseous product water passes through the filter 112 and enters the low-pressure cylinder 104 of the steam turbine. The solid product calcium oxide flows to the feedwater preheater 203, releasing heat to the feedwater. After absorbing heat, the feedwater returns to the preheated feedwater junction and enters the boiler 101. The calcium oxide flows through the evaporator 301, releasing heat, and then enters the calcium oxide storage tank 205. The ammonia-water mixture is pressurized by pump 309 to become a low-temperature, high-pressure saturated solution. The saturated solution is then sequentially passed through the second regenerator. After being heated by the first regenerator 302 and the first regenerator 307, the mixture enters the evaporator 301, which uses the sensible heat of the calcium-based material as a heat source, and is heated to a high-temperature and high-pressure gas-liquid mixture. Then it enters the separator 303 for separation. The rich ammonia vapor enters the turbine 304 to expand and do work, driving the generator to generate electricity. The lean ammonia solution serves as the heat source. The first regenerator 302 mixes the lean ammonia solution, which has been depressurized and cooled by the pressure relief valve 305, and the rich ammonia solution, which has been done by the turbine 304, through the mixer 306. The mixture then serves as the heat source and is introduced into the second regenerator 307. Finally, the ammonia-water mixture is condensed to a low temperature and low pressure through the condenser 308.

[0074] S120. When there is insufficient sunlight, the photovoltaic-thermochemical subsystem terminates photovoltaic power generation and performs thermochemical reaction to release heat to assist the coal-fired unit in increasing its load, making up for the photovoltaic shortfall, maintaining a constant total output, and the Karina cycle realizes the utilization of sensible heat and waste heat from the thermochemical reaction products.

[0075] Specifically, during periods of insufficient light:

[0076] In the coal-fired power generation system, the steam injection port of the low-pressure cylinder 104 of the steam turbine is closed, the steam extraction pipe diversion point of the low-pressure cylinder 104 of the steam turbine is open, the filter 112 is not working, and the throttle valve 113 is working; in the photovoltaic-thermochemical subsystem, the dehydration reaction bed 201 and the photovoltaic device are not working, except for the thermochemical device and the heat exchanger device, all of which are working normally; all devices in the Karina cycle subsystem are working normally.

[0077] Steam extracted from the low-pressure cylinder 104 of the steam turbine flows through throttle valve 113 into the hydration reactor 204. Calcium oxide particles from the calcium oxide storage tank 205 enter the hydration reactor 204 to undergo chemical reaction. The split cold reheat steam is fed into the hydration reactor 204 to absorb the heat of reaction, and then flows back to the preheating reheat steam junction point and enters the boiler 101. The solid product, calcium hydroxide, flows to the feedwater preheater 203 to release heat to the split feedwater. After absorbing heat, the feedwater flows back to the preheating feedwater junction point and enters the boiler 101. The calcium hydroxide flows through the evaporator 301 to release heat and then enters the calcium hydroxide storage tank 206. The ammonia-water mixture is pressurized by pump 309 to become a low-temperature, high-pressure saturated solution. The saturated solution is sequentially fed into the second regenerator 307 and the first regenerator 302 to raise its temperature. Then it enters the evaporator 301, which uses the sensible heat of the calcium-based material as a heat source, and is heated to a high-temperature and high-pressure gas-liquid mixture. After that, it enters the separator 303 for separation. The rich ammonia vapor enters the turbine 304 to expand and do work, driving the generator to generate electricity. The lean ammonia solution serves as the heat source in the first regenerator 302. The lean ammonia solution, which has been depressurized and cooled by the pressure relief valve 305, and the rich ammonia solution, which has been done by the turbine 304, are mixed in the mixer 306 and then fed into the second regenerator 307 as a heat source. Finally, the ammonia-water mixture is condensed to a low temperature and low pressure by the condenser 308.

[0078] When there is sufficient sunlight, some of the photovoltaic power is directly fed into the grid, and the remainder drives thermochemical reactions for heat storage, reducing the load of coal-fired units. The Karina cycle realizes the utilization of sensible and waste heat from the thermochemical reaction products. When there is insufficient sunlight, the heat released by the thermochemical reaction assists the coal-fired units in increasing their load, making up for the photovoltaic shortfall and maintaining a constant total output. The Karina cycle realizes the utilization of sensible and waste heat from the thermochemical reaction products.

[0079] The temperature of the thermochemical reaction is controlled by the reaction pressure. The operating status of the unit can be matched in real time by adjusting the parameters of each component in the photovoltaic-thermochemical subsystem, and high-grade thermal energy can be safely and stably stored in the form of chemical energy.

[0080] The Karina cycle undergoes temperature slippage during evaporation, which effectively matches the temperature drop process of calcium-based material particles and significantly reduces irreversible heat transfer losses. It also has significant advantages in waste heat recovery and achieving efficient energy utilization by dynamically adjusting the ammonia concentration to match heat source fluctuations.

[0081] The present invention discloses a method for operating a coal-fired power unit system that couples solar energy, electrical energy, and chemical energy, dynamically adjusting according to sunlight conditions: When sunlight is sufficient, the photovoltaic power portion is connected to the grid, and the remainder drives the dehydration and heat storage of calcium hydroxide. The released steam is then fed into the low-pressure cylinder of the coal-fired power unit, while the Karina cycle recovers the sensible heat of calcium oxide for power generation. When sunlight is insufficient, the hydration of calcium oxide releases heat to heat the reheat steam and feedwater of the coal-fired power unit, and the auxiliary unit increases its load to compensate for the photovoltaic shortfall. The Karina cycle simultaneously recovers the sensible heat of calcium hydroxide. Through the complementary output of solar and coal power and the cross-time scheduling of chemical energy, flexible peak shaving of the coal-fired power unit, efficient photovoltaic absorption, and deep utilization of waste heat under all operating conditions are achieved. The present invention achieves matching of the heat storage / release temperature with the coal-fired system through thermochemical reaction pressure control, combined with dynamic adjustment of the working fluid concentration in the Karina cycle, significantly reducing irreversible heat transfer losses and improving overall energy utilization efficiency.

[0082] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A coal-fired power unit system coupling solar energy, electrical energy, and chemical energy, characterized in that, This includes a coal-fired power generation system, a photovoltaic-thermochemical subsystem, and a Karina cycle subsystem; The coal-fired power generation system is connected to the photovoltaic-thermochemical subsystem, and the photovoltaic-thermochemical subsystem is connected to the Karina cycle subsystem; wherein... The coal-fired power generation system is used for basic power generation and peak shaving of the entire system. The photovoltaic-thermochemical subsystem is used to convert solar energy into electrical energy through a photovoltaic device, and to use the electrical energy to drive a reversible thermochemical device based on calcium-based compounds, thereby realizing the conversion and storage of electrical energy, thermal energy and chemical energy. The Karina cycle subsystem is used for the utilization of waste heat from thermochemical reaction products.

2. The system according to claim 1, characterized in that, The photovoltaic-thermochemical subsystem includes the photovoltaic device, the thermochemical device, and the heat exchanger device; The photovoltaic device includes a photovoltaic-driven electric heater; the thermochemical device includes a dehydration reactor; The coal-fired power generation system includes a filter and a low-pressure turbine cylinder connected to the filter; The first inlet of the dehydration reactor is connected to the electric heater, and the first outlet of the dehydration reactor is connected to the steam injection port of the low-pressure cylinder of the steam turbine through the filter; wherein... The electric heater drives the decomposition of calcium hydroxide in the dehydration reactor, realizing the conversion of electrical energy to thermal energy to chemical energy. The water vapor generated by the reaction is connected to the steam injection port of the low-pressure cylinder of the steam turbine through the filter.

3. The system according to claim 2, characterized in that, The heat exchanger unit includes a feedwater preheater; the Karina circulation subsystem includes an evaporator; the thermochemical unit also includes a calcium oxide storage tank; The first inlet of the feedwater preheater is connected to the second outlet of the dewatering reactor, and the first outlet of the feedwater preheater is connected to the first inlet of the evaporator. The inlet of the calcium oxide storage tank is connected to the first outlet of the evaporator; wherein, The calcium oxide produced by the dehydration reactor is sent to the water preheater to release heat. The released calcium oxide is then sent to the evaporator to further release heat to drive the Karina cycle. After the heat is released again, the calcium oxide is sent to the calcium oxide storage tank for storage.

4. The system according to claim 3, characterized in that, The thermochemical apparatus also includes a hydration reactor and a calcium hydroxide storage tank; the coal-fired power generation system also includes a low-pressure turbine cylinder and a throttle valve. The first outlet of the calcium oxide storage tank is connected to the first inlet of the hydration reactor. The low-pressure cylinder of the steam turbine is connected to the second inlet of the hydration reactor via the throttle valve; The first outlet of the evaporator is connected to the inlet of the calcium hydroxide storage tank, and the outlet of the calcium hydroxide storage tank is connected to the dehydration reactor.

5. The system according to claim 4, characterized in that, The coal-fired power generation system also includes a high-pressure heater, a boiler, and a high-pressure cylinder for the steam turbine. The outlet and inlet of the feedwater preheater are respectively connected to the high-pressure heater and the boiler; The inlet of the hydration reactor is connected to both the boiler and the high-pressure cylinder of the steam turbine.

6. The system according to claim 4, characterized in that, The dehydration reactor and the hydration reactor operate at atmospheric pressure in a temperature range of 490℃~540℃. The temperature range of the calcium-based material after it flows out of the feedwater preheater and before it enters the evaporator is 260℃~310℃.

7. The system according to claim 4, characterized in that, The Karina cycle subsystem also includes a separator and a first regenerator; The inlet of the separator is connected to the second outlet of the evaporator, the first outlet of the separator is connected to the first inlet of the first regenerator, and the first outlet of the first regenerator is connected to the second inlet of the evaporator.

8. The system according to claim 7, characterized in that, The Karina cycle subsystem also includes a turbine, a mixer, a pressure relief valve, and a second regenerator; The turbine inlet is connected to the second outlet of the separator, and the turbine outlet is connected to the mixer; The pressure relief valve is connected to the first regenerator and the mixer, respectively; The first inlet of the second regenerator is connected to the outlet of the mixer, and the first outlet of the second regenerator is connected to the second inlet of the first regenerator.

9. The system according to claim 8, characterized in that, The Karina circulation subsystem also includes pumps and condensers; The inlet of the condenser is connected to the second outlet of the second regenerator, the outlet of the condenser is connected to the inlet of the pump, and the outlet of the pump is connected to the second inlet of the second regenerator.

10. A method for operating a coal-fired power unit system that couples solar energy, electrical energy, and chemical energy, characterized in that, The coal-fired power unit system for coupling solar energy, electrical energy, and chemical energy as described in any one of claims 1 to 9; the operating method includes: During periods of sufficient sunlight, the photovoltaic devices in the photovoltaic-thermochemical subsystem generate electricity, part of which is transmitted to the grid, and the remaining electricity drives the thermochemical reaction for heat storage. The coal-fired power generation system reduces its own load, and the Karina cycle subsystem realizes the utilization of sensible heat and waste heat from the thermochemical reaction products. When sunlight is insufficient, the photovoltaic-thermochemical subsystem terminates photovoltaic power generation and performs thermochemical reactions to release heat, assisting the coal-fired unit to increase its load, making up for the photovoltaic shortfall, and maintaining a constant total output. The Karina cycle realizes the utilization of sensible heat and waste heat from the thermochemical reaction products.

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