A coal-fired power generation-heat pump integrated power generation system for energy level enhancement

Abstract

This invention discloses an integrated coal-fired power generation and heat pump power generation system for energy level enhancement and utilization, belonging to the technical field of the power industry. It includes a coal-fired power generation system and a heat pump power generation system. The coal-fired power generation system includes a boiler, a feedwater heat exchanger, and a steam turbine power generation unit. The heat pump power generation system includes a turbine generator set, an evaporator, a regenerator, a compressor, a condenser, a motor, a high-temperature heat storage device, and a low-temperature heat storage device. During energy storage, the lower-temperature steam from the coal-fired power generation system is used as the evaporative heat source for the heat pump power generation system. This allows for a smaller power loss while improving the coefficient of performance of the heat pump, thereby increasing the system's energy utilization efficiency. During discharge, the high-temperature heat storage device heats the feedwater at the economizer inlet, avoiding the water evaporation phase change process, reducing heat exchange losses in the working fluid, and simultaneously increasing the economizer inlet water temperature, reducing the average heat exchange temperature difference between flue gas and liquid water within the economizer, and improving the system's efficiency.

Description

Technical Field

[0001] This invention relates to the field of power industry technology, and in particular to a coal-fired power generation-heat pump integrated power generation system for energy level enhancement and utilization. Background Technology

[0002] With the rapid growth of installed capacity of renewable energy, the intermittency and volatility of renewable electricity pose a severe challenge to the stable operation of the power system. As a crucial baseload power source for the current power grid, coal-fired power plants urgently need improved power regulation flexibility to mitigate fluctuations in renewable energy generation. Against this backdrop, upgrading existing coal-fired units to enhance their peak-shaving capabilities has become an urgent need for the power industry.

[0003] Integrated Carnot batteries are a large-scale power storage technology based on the Carnot cycle principle, achieving efficient energy storage and release through an electro-thermal-electric cycle. A Carnot battery includes a heat conversion device, a high-temperature heat storage device, a low-temperature heat storage device, and a heat release device. Current flexible retrofitting technologies for coal-fired power plants, utilizing integrated Carnot batteries, offer advantages such as high energy efficiency, wide load regulation range, and strong scalability, and have received widespread attention in recent years. However, existing technologies primarily focus on utilizing turbine-side steam extraction heat storage: during periods of low electricity load, the unit needs deep peak shaving, storing some of the heat energy extracted from the turbine in the storage medium to reduce the unit's output power; during periods of high electricity load, the unit needs peak power generation, releasing the stored heat energy and returning it to the thermal system to increase the unit's output power. However, this traditional approach struggles to balance peak shaving capacity and energy utilization efficiency. Specifically, storing the sensible heat of the steam results in high energy utilization efficiency due to low heat exchange losses, but its peak shaving capacity is limited. If a combined steam sensible heat and latent heat storage method is further adopted, the peak-shaving capability can be significantly enhanced. However, there is a large irreversible loss in phase change heat transfer, and the energy utilization efficiency is significantly reduced.

[0004] Therefore, given the bottlenecks in existing coal-fired power plant peak-shaving technologies with integrated Carnot battery energy storage, there is an urgent need to develop an innovative system configuration based on existing integrated Carnot batteries that can significantly enhance the unit's peak-shaving capacity while ensuring high energy utilization efficiency. This is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems and provide a coal-fired power generation-heat pump integrated power generation system with enhanced thermal energy utilization. During the energy storage process, the lower-temperature steam in the coal-fired power generation system is used as the evaporation heat source for the heat pump power generation system. This can improve the coefficient of performance of the heat pump at the cost of less power loss, thereby improving the energy utilization efficiency of the system. During the discharge process, the high-temperature heat storage device is used to heat the feedwater at the economizer inlet. This not only avoids the water evaporation phase change process and reduces the heat loss of the working fluid, but also increases the inlet water temperature of the economizer, reduces the average heat exchange temperature difference between flue gas and liquid water in the economizer, and improves the overall efficiency of the entire system. This system can enhance the peak-shaving capacity of the unit while ensuring high energy utilization efficiency.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention discloses an integrated coal-fired power generation and heat pump power generation system for energy level enhancement and utilization, including a coal-fired power generation system and a heat pump power generation system; The coal-fired power generation system includes a boiler, a feedwater heat exchanger, and a steam turbine power generation device. The boiler includes a steam outlet, a steam return port, and an economizer feedwater inlet. The steam outlet is connected to the steam inlet of the steam turbine power generation device, the steam return port is connected to the steam outlet of the steam turbine power generation device, and the return water end of the steam turbine power generation device is connected to the economizer feedwater inlet through the first heat exchange passage of the feedwater heat exchanger. The heat pump power generation system includes a turbine generator set, an evaporator, a regenerator, a compressor, a condenser, a motor, a high-temperature heat storage device, and a low-temperature heat storage device. The inlet of the evaporator's heat source pipeline is connected to the steam outlet of the steam turbine generator set, and the outlet of the evaporator's heat source pipeline is connected to the water return end of the steam turbine generator set. The outlet of the evaporator's medium pipeline is connected to the inlet of the first heat exchange passage of the regenerator, and the outlet of the first heat exchange passage of the regenerator is connected to the inlet of the compressor. The outlet of the compressor is connected to the inlet of the medium pipeline of the condenser. The outlet of the medium pipeline is connected to the inlet of the second heat exchange passage of the regenerator, the outlet of the second heat exchange passage of the regenerator is connected to the inlet of the turbine generator set, and the outlet of the turbine generator set is connected to the inlet of the medium pipeline of the evaporator; the outlet of the cold source pipeline of the condenser is connected to the inlet of the high-temperature thermal storage device, the outlet of the high-temperature thermal storage device is connected to the inlet of the second heat exchange passage of the feedwater heat exchanger, the outlet of the second heat exchange passage of the feedwater heat exchanger is connected to the inlet of the low-temperature thermal storage device, and the outlet of the low-temperature thermal storage device is connected to the inlet of the cold source pipeline of the condenser.

[0007] Preferably, the high-temperature thermal storage device is a high-temperature molten salt tank, and the low-temperature thermal storage device is a low-temperature molten salt tank.

[0008] Preferably, the heat pump power generation system further includes a circulation pump, and the outlet of the cold source pipeline of the condenser is connected to the inlet of the high-temperature molten salt tank through the circulation pump.

[0009] Preferably, a first valve is provided between the inlet of the high-temperature molten salt tank and the circulating pump, and a second valve is provided between the outlet of the low-temperature molten salt tank and the condenser.

[0010] Preferably, the two ends of the compressor's power shaft are coaxially and fixedly connected to the motor shaft of the electric motor and the power shaft of the turbine generator set, respectively.

[0011] Preferably, the steam outlet includes a primary hot steam outlet and a reheat steam outlet; The steam turbine power generation unit includes a high-pressure cylinder, a low-pressure cylinder, an intermediate-pressure cylinder, a high-pressure heat exchanger group, an intermediate-pressure heat exchanger group, a low-pressure heat exchanger group, a generator, a condenser, and a return water pipeline; the high-pressure heat exchanger group includes a first high-pressure heat exchanger and a second high-pressure heat exchanger; the intermediate-pressure heat exchanger group includes a first intermediate-pressure heat exchanger and a second intermediate-pressure heat exchanger; the low-pressure heat exchanger group includes a first low-pressure heat exchanger and a second low-pressure heat exchanger. The primary hot steam outlet is connected to the steam inlet of the high-pressure cylinder, the first steam outlet of the high-pressure cylinder is connected to the inlet of the first heat exchange passage of the second high-pressure heat exchanger and the steam return port, and the second steam outlet of the high-pressure cylinder is connected to the inlet of the first heat exchange passage of the first high-pressure heat exchanger. The reheat steam outlet is connected to the steam inlet of the intermediate-pressure cylinder, the first steam outlet of the intermediate-pressure cylinder is connected to the inlet of the first heat exchange passage of the first intermediate-pressure heat exchanger, the second steam outlet of the intermediate-pressure cylinder is connected to the inlet of the first heat exchange passage of the second intermediate-pressure heat exchanger, the third steam outlet of the intermediate-pressure cylinder is connected to the inlet of the heat source pipeline of the evaporator and the inlet of the low-pressure cylinder respectively, and the outlet of the heat source pipeline inside the evaporator is connected to the return water pipeline of the steam power generation unit. The first steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the first low-pressure heat exchanger, the second steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger, and the third steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger through the condenser. The outlet of the first heat exchange passage of the first high-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the second high-pressure heat exchanger, and the outlet of the first heat exchange passage of the second high-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the first medium-pressure heat exchanger; the outlet of the first heat exchange passage of the second medium-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the first low-pressure heat exchanger, the outlet of the first heat exchange passage of the first low-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger, and the outlet of the first heat exchange passage of the second low-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the condenser. The outlet of the first heat exchange passage of the condenser is connected to the inlet of the second heat exchange passage of the second low-pressure heat exchanger, and the outlet of the second heat exchange passage of the second low-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the first low-pressure heat exchanger; the outlet of the second heat exchange passage of the first low-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the second medium-pressure heat exchanger; the outlet of the first medium-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the second high-pressure heat exchanger, and the outlet of the second heat exchange passage of the second high-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the first high-pressure heat exchanger; the outlet of the second heat exchange passage of the first high-pressure heat exchanger is connected to the inlet of the medium pipeline of the feedwater heat exchanger, and the outlet of the medium pipeline of the feedwater heat exchanger is connected to the return port.

[0012] Preferably, the outlet of the heat source pipeline of the evaporator is connected to the inlet of the second heat exchange passage of the second medium-pressure heat exchanger.

[0013] Preferably, the third steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the condenser, and the outlet of the first heat exchange passage of the condenser is connected to the inlet of the second low-pressure heat exchanger via a condensate pump; the outlet of the second low-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the condenser.

[0014] Preferably, the steam turbine power generation device further includes a deaerator and a feedwater pump; the fourth steam outlet of the intermediate pressure cylinder and the outlet of the first heat exchange passage of the first intermediate pressure heat exchanger are both connected to the inlet of the deaerator, the outlet of the second heat exchange passage of the second intermediate pressure heat exchanger is connected to the inlet of the deaerator, and the outlet of the deaerator is connected to the inlet of the second heat exchange passage of the first intermediate pressure heat exchanger through the feedwater pump.

[0015] Preferably, the output shafts of the high-pressure cylinder, the intermediate-pressure cylinder, the low-pressure cylinder, and the generator are coaxially connected.

[0016] The present invention achieves the following technical effects compared to the prior art: In the energy-level enhancement and utilization coal-fired power generation-heat pump integrated power generation system of this invention, during the energy storage process, the lower-temperature steam in the coal-fired power generation system is used as the evaporation heat source for the heat pump power generation system. This allows the redundant electrical energy of the coal-fired power plant to drive the compressor to compress the circulating working fluid through an electric motor, and then transfer the heat energy to molten salt for energy storage through a condenser. This scheme can significantly improve the performance coefficient of the heat pump in the heat pump power generation system at the cost of relatively small power loss in the coal-fired power generation system, thereby improving the energy utilization efficiency of the system. During the discharge process, the high-temperature heat storage device is used to heat the higher-temperature feedwater at the economizer inlet, instead of heating the feedwater in the traditional system. The approach of using water to generate main steam and heat feedwater to replace extraction steam in high / low pressure heat exchangers not only avoids the phase change process of water evaporation and reduces heat loss in the system's working fluid, but also increases the inlet water temperature of the economizer, effectively reducing the average heat exchange temperature difference between flue gas and liquid water in the economizer, thereby significantly improving the overall efficiency of the entire system. This system uses heated feedwater to release heat, eliminating the need for high heat storage temperatures. This means the heat pump compressor outlet temperature does not need to reach a high level, which on the one hand improves the coefficient of performance of the heat pump, and on the other hand significantly reduces the manufacturing difficulty and processing cost of the compressor, improving the feasibility of the system's engineering applications. Attached Figure Description

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

[0018] Figure 1 This is a schematic diagram of the structure of the coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization in an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Coal-fired power generation system; 101. Boiler; 102. Feedwater heat exchanger; 103. High-pressure cylinder; 104. Intermediate-pressure cylinder; 105. Low-pressure cylinder; 106. Generator; 107. Deaerator; 108. Feedwater pump; 109. Condenser; 110. Condensate pump; 111. First high-pressure heat exchanger; 112. Second high-pressure heat exchanger; 113. First intermediate-pressure heat exchanger; 114. Second intermediate-pressure heat exchanger; 1 15. First low-pressure heat exchanger; 116. Second low-pressure heat exchanger; 117. Third valve; 118. Fourth valve; 2. Heat pump power generation system; 201. Evaporator; 202. Turbine generator set; 203. Regenerator; 204. Compressor; 205. Electric motor; 206. Condenser; 207. High-temperature molten salt tank; 208. Low-temperature molten salt tank; 209. Circulating pump; 210. First valve; 211. Second valve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments analyzed and obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide an integrated coal-fired power generation system with heat pump for enhanced energy utilization, in order to solve the problems existing in the prior art. During the energy storage process, the lower-temperature steam in the coal-fired power generation system is used as the evaporation heat source for the heat pump power generation system. This can improve the coefficient of performance of the heat pump at the cost of less power loss, thereby improving the energy utilization efficiency of the system. During the discharge process, the high-temperature heat storage device is used to heat the feedwater at the economizer inlet. This not only avoids the water evaporation phase change process and reduces the heat loss of the working fluid, but also increases the inlet water temperature of the economizer, reduces the average heat exchange temperature difference between flue gas and liquid water in the economizer, and improves the overall efficiency of the entire system.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Note: In this article, high temperature, medium temperature and low temperature are relative concepts among the three.

[0024] To achieve the above objectives, the present invention provides the following solution: like Figure 1 As shown, this embodiment provides a coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization. The system is divided into two main parts: coal-fired power generation system 1 and heat pump power generation system 2.

[0025] The coal-fired power generation system 1 includes a boiler 101, a feedwater heat exchanger 102, and a steam turbine power generation device. The boiler 101 includes a steam outlet, a steam return outlet, and an economizer feedwater inlet. Since the boiler 101 is existing technology, its working principle and structure will not be described in detail. The steam outlet of the boiler 101 is connected to the steam inlet of the steam turbine power generation device, allowing the steam generated by the boiler 101 to enter the device, where high-pressure steam is used to generate electricity. The steam return outlet of the boiler 101 is connected to the steam outlet of the steam turbine power generation device, recovering a portion of the steam after the steam turbine power generation device has performed its work. The feedwater inlet of the boiler 101 and the return outlet of the steam turbine power generation device are connected through the first heat exchange passage of the feedwater heat exchanger 102. The condensate formed from the steam in the steam turbine power generation device returns to the boiler 101 through the economizer feedwater inlet, serving as a steam source.

[0026] The heat pump power generation system 2 includes a turbine generator set 202, an evaporator 201, a regenerator 203, a compressor 204, a condenser 206, an electric motor 205, a high-temperature heat storage device (e.g., a high-temperature molten salt tank 207), and a low-temperature heat storage device (e.g., a low-temperature molten salt tank 208). The inlet of the heat source pipeline of the evaporator 201 is connected to the steam outlet of the steam turbine generator set, and the outlet of the heat source pipeline of the evaporator 201 is connected to the return water outlet of the steam turbine generator set. The outlet of the medium pipeline of the evaporator 201 is connected to the inlet of the first heat exchange passage of the regenerator 203, and the outlet of the first heat exchange passage of the regenerator 203 is connected to the inlet of the compressor 204. The outlet of the compressor 204 is connected to the inlet of the medium pipeline of the condenser 206, and the outlet of the medium pipeline of the condenser 206 is connected to the inlet of the second heat exchange passage of the regenerator 203. The outlet of the second heat exchange passage of the regenerator 203 is connected to the inlet of the turbine generator set 202, and the outlet of the turbine generator set 202 is connected to the inlet of the medium pipeline of the evaporator 201. The outlet of the cold source pipeline of the condenser 206 is connected to the inlet of the high-temperature thermal storage device, the outlet of the high-temperature thermal storage device is connected to the inlet of the second heat exchange passage of the feedwater heat exchanger 102, the outlet of the second heat exchange passage of the feedwater heat exchanger 102 is connected to the inlet of the low-temperature thermal storage device, and the outlet of the low-temperature thermal storage device is connected to the inlet of the cold source pipeline of the condenser 206. The high-temperature thermal storage device (e.g., high-temperature molten salt tank 207) and the low-temperature thermal storage device (e.g., low-temperature molten salt tank 208) form a Carnot battery energy storage function. This makes the coal-fired power generation-heat pump integrated power generation system with improved energy utilization a highly efficient integrated peak-shaving power generation system capable of achieving improved energy utilization of thermal battery-boiler-generator set.

[0027] Working principle: The power generation process of the coal-fired power generation system: Boiler 101 transmits high-temperature and high-pressure steam to the steam turbine power generation device through the steam outlet. The steam turbine power generation device uses this high-temperature and high-pressure steam to generate electricity. The high-temperature steam in the steam turbine power generation device flows back to boiler 101 through the steam return port of boiler 101. The medium-temperature steam flows into the evaporator 201 of the heat pump power generation system 2. The low-temperature steam finally becomes condensate and flows back to boiler 101 through the economizer feed port of boiler 101 to participate in the next cycle as a steam source. The power generation process of the heat pump power generation system: After the medium-temperature steam flows into the heat source pipeline of the evaporator 201, it exchanges heat with the circulating medium in the medium pipeline of the evaporator 201, heating the circulating medium. The heated circulating medium then flows into the first heat exchange passage of the regenerator 203, where it exchanges heat with the low-temperature medium in the second heat exchange passage of the regenerator 203 (the regenerator 203 should be installed or turned on based on the actual heat storage requirements and extraction steam temperature). This causes the circulating medium in the second heat exchange passage to heat up, while the medium in the first heat exchange passage cools down. The circulating medium flowing out of the first heat exchange pipeline of the regenerator 203 enters the compressor 204 for further processing. The medium is pressurized and then enters the medium pipeline of condenser 206 to exchange heat with the energy storage medium in the cold source pipeline of condenser 206. The energy storage medium in the medium pipeline cools down and the energy storage medium in the cold source pipeline heats up. Then, the circulating medium in the medium pipeline flows into the second heat exchange passage of regenerator 203 to exchange heat with the circulating medium in the first heat exchange passage of regenerator 203. The heated circulating medium in the second heat exchange passage of regenerator 203 enters the turbine generator set 202 to do work, so that the turbine generator set 202 generates electricity. After the work is completed, the circulating medium flows into the medium pipeline of evaporator 201 for the next power generation cycle. The heat storage and release process of a heat pump power generation system: During heat storage, the energy storage medium in the low-temperature heat storage device flows into the cold source pipeline of the condenser 206 and exchanges heat with the circulating medium in the medium pipeline. Then, the energy storage medium in the cold source pipeline of the condenser 206, after absorbing heat, is heated by the circulating medium in the medium pipeline and flows into the high-temperature heat storage device for heat storage. When releasing heat, the energy storage medium in the high-temperature heat storage device flows out and into the feedwater heat exchanger 102 to exchange heat with the return water (condensate) flowing back to the boiler 101 from the steam turbine power generation device. After being heated, the return water flows into the boiler 101 to increase the unit efficiency. Meanwhile, the energy storage medium is cooled and then replenished into the low-temperature heat storage device.

[0028] In one embodiment, the energy storage medium in the high-temperature thermal storage device and the low-temperature thermal storage device can be materials such as binary salt, ternary salt, and heat transfer oil.

[0029] In one embodiment, the medium flowing within the heat pump power generation system 2 can be a gas such as air, argon, nitrogen, helium, or carbon dioxide.

[0030] In one embodiment, the high-temperature thermal storage device uses a high-temperature molten salt tank 207, and the low-temperature thermal storage device uses a low-temperature molten salt tank 208. The energy storage function is achieved by absorbing and releasing heat through the molten salt in the high-temperature molten salt tank 207 and the low-temperature molten salt tank 208.

[0031] In one embodiment, the heat pump power generation system 2 further includes a circulation pump 209. The outlet of the cold source pipeline of the condenser 206 is connected to the inlet of the high-temperature molten salt tank 207 through the circulation pump 209. The flow of the circulation pump 209 drives the flow of the energy storage medium in the high-temperature molten salt tank 207 and the low-temperature molten salt tank 208. certainly The circulating pump 209 can also be installed between the low-temperature molten salt tank 208 and the condenser 206. The outlet of the low-temperature molten salt tank 208 is connected to the inlet of the cold source pipeline of the condenser 206 through the circulating pump 209.

[0032] In one embodiment, a first valve 210 is provided between the inlet of the high-temperature molten salt tank 207 and the circulating pump 209, and a second valve 211 is provided between the outlet of the low-temperature molten salt tank 208 and the condenser 206. The first valve 210 and the second valve 211 can control the flow rate and start / stop of the energy storage medium.

[0033] In one embodiment, the two ends of the power shaft of compressor 204 are coaxially and fixedly connected to the motor shaft of motor 205 and the power shaft of turbine generator set 202, respectively. Alternatively, the three can be connected via a gearbox. During periods of low electricity demand, the power shaft of compressor 204, driven by turbine generator set 202 and motor 205, rotates to compress the circulating working fluid. In the process of outputting electrical energy from the coal-fired power plant (coal-fired power generation system 1), the steam thermal energy is converted into circulating working fluid thermal energy, and heat is exchanged with low-temperature molten salt from low-temperature molten salt tank 208 through condenser 206, achieving deep peak shaving for the coal-fired power plant (coal-fired power generation system 1).

[0034] In one embodiment, the steam outlet includes a primary steam outlet and a reheat steam outlet.

[0035] The steam turbine power generation unit includes a high-pressure cylinder 103, a low-pressure cylinder 105, a medium-pressure cylinder 104, a high-pressure heat exchanger group, a medium-pressure heat exchanger group, a low-pressure heat exchanger group, a generator 106, a condenser 109, and a return water pipeline.

[0036] The high-pressure heat exchanger assembly includes a first high-pressure heat exchanger 111 and a second high-pressure heat exchanger 112. The medium-pressure heat exchanger assembly includes a first medium-pressure heat exchanger 113 and a second medium-pressure heat exchanger 114; The low-pressure heat exchanger assembly includes a first low-pressure heat exchanger 115 and a second low-pressure heat exchanger 116.

[0037] The initial hot steam outlet is connected to the steam inlet of the high-pressure cylinder 103. The initial hot steam in the boiler 101 enters the high-pressure cylinder 103 to perform work. The first steam outlet of the high-pressure cylinder 103 is connected to the inlet of the first heat exchange passage of the second high-pressure heat exchanger 112 and the steam return port of the boiler 101. The second steam outlet of the high-pressure cylinder 103 is connected to the inlet of the first heat exchange passage of the first high-pressure heat exchanger 111. After the initial hot steam in the high-pressure cylinder 103 has completed its work, it returns to the boiler 101 and enters the first high-pressure heat exchanger 111 and the second high-pressure heat exchanger 112. Returning part of the initial hot steam to the boiler 101 for reheating is to reduce energy consumption. Specifically, after the steam generated in the boiler 101 enters the steam turbine power generation device to perform work, the pressure and temperature of the steam will drop significantly (for example, the steam drops from 24MPa and 566℃ to 3MPa-5MPa and 200℃-300℃). At this time, the steam still contains a large amount of unutilized heat energy. If the used steam is directly input into the return water pipeline, it will cause serious energy waste. Therefore, the steam used in the high-pressure cylinder 103 is returned to the boiler 101 for reheating. The steam temperature can rise to 566℃ or even higher (e.g., the secondary reheat steam temperature in a double reheat unit can reach 620℃), and the pressure will also return to the medium-pressure level (approximately 3MPa-5MPa), thus restoring its work capacity and continuing to drive the turbine rotation in the medium- and low-pressure cylinders 105, significantly improving the energy utilization rate of the steam. The steam temperature and pressure values ​​mentioned above are merely illustrative examples.

[0038] The reheat steam outlet is connected to the steam inlet of the intermediate-pressure cylinder 104. The preheated steam in the high-pressure cylinder 103 returns to the boiler 101 for secondary heating and then enters the intermediate-pressure cylinder 104 through the reheat steam outlet. The first steam outlet of the intermediate-pressure cylinder 104 is connected to the inlet of the first heat exchange passage of the first intermediate-pressure heat exchanger 113. The second steam outlet of the intermediate-pressure cylinder 104 is connected to the inlet of the first heat exchange passage of the second intermediate-pressure heat exchanger 114. The third steam outlet of the intermediate-pressure cylinder 104 is connected to the inlet of the heat source pipeline of the evaporator 201 and the inlet of the low-pressure cylinder 105, respectively. The outlet of the heat source pipeline in the evaporator 201 is connected to the return water pipeline of the steam power generation unit. The steam in the intermediate-pressure cylinder 104 enters the first intermediate-pressure heat exchanger 113, the second intermediate-pressure heat exchanger 114, the evaporator 201, and the low-pressure cylinder 105 for subsequent use of the reheat steam.

[0039] The first steam outlet of the low-pressure cylinder 105 is connected to the inlet of the first heat exchange passage of the first low-pressure heat exchanger 115, the second steam outlet of the low-pressure cylinder 105 is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger 116, and the third steam outlet of the low-pressure cylinder 105 is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger 116 via the condenser 109. The steam in the low-pressure cylinder 105 enters the first low-pressure heat exchanger 115, the second low-pressure heat exchanger 116, and the condenser 109, respectively. The steam serves the purpose of heat exchange, further utilizing the heat within the steam and reducing heat loss within the device.

[0040] The outlet of the first heat exchange passage of the first high-pressure heat exchanger 111 is connected to the inlet of the first heat exchange passage of the second high-pressure heat exchanger 112. Steam that has completed heat exchange in the first high-pressure heat exchanger 111 enters the second high-pressure heat exchanger 112 for secondary utilization. Steam circulates within each heat exchanger layer and stage, increasing steam utilization. The outlet of the first heat exchange passage of the second high-pressure heat exchanger 112 is connected to the inlet of the first heat exchange passage of the first medium-pressure heat exchanger 113. The outlet of the first heat exchange passage of the second medium-pressure heat exchanger 114 is connected to the inlet of the first heat exchange passage of the first low-pressure heat exchanger 115. The outlet of the first heat exchange passage of the first low-pressure heat exchanger 115 is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger 116. The outlet of the first heat exchange passage of the second low-pressure heat exchanger 116 is connected to the inlet of the first heat exchange passage of the condenser 109. Finally, the steam arriving in the second low-pressure heat exchanger 116 enters the condenser 109 for heat exchange.

[0041] The outlet of the first heat exchange passage of condenser 109 is connected to the inlet of the second heat exchange passage of the second low-pressure heat exchanger 116. Steam entering condenser 109 from low-pressure cylinder 105 serves as the heat exchange medium. After transferring heat within condenser 109, the steam liquefies into water, which then enters the second heat exchange passage of the second low-pressure heat exchanger 116. At this point, the steam in the first heat exchange passage of the second low-pressure heat exchanger 116 exchanges heat with the water in the second heat exchange passage, causing the temperature of the steam in the first heat exchange passage to decrease and the temperature of the water in the second heat exchange passage to increase. The outlet of the second heat exchange passage of the second low-pressure heat exchanger 116 is connected to the inlet of the second heat exchange passage of the first low-pressure heat exchanger 115. The outlet of the second heat exchange passage of the first low-pressure heat exchanger 115 is connected to the inlet of the second heat exchange passage of the second intermediate-pressure heat exchanger 114. The outlet of the first intermediate-pressure heat exchanger 113 is connected to the inlet of the second heat exchange passage of the second high-pressure heat exchanger 112. The outlet of the second heat exchange passage of the second high-pressure heat exchanger 112 is connected to the inlet of the second heat exchange passage of the first high-pressure heat exchanger 111. The outlet of the second heat exchange passage of the first high-pressure heat exchanger 111 is connected to the inlet of the medium pipeline of the feedwater heat exchanger 102, and the outlet of the medium pipeline of the feedwater heat exchanger 102 is connected to the return port. The water in the second heat exchange passage of each heat exchanger flows sequentially and exchanges heat with the steam in the first heat exchange passage, causing the steam temperature to decrease and the water temperature to increase.

[0042] In one embodiment, steam from either the high-pressure cylinder 103 or the low-pressure cylinder 105 can enter the evaporator 201 of the heat pump power generation system 2; using only steam from the intermediate-pressure cylinder 104 to enter the evaporator 201 is not the only option. Furthermore, steam from the high-pressure cylinder 103, the intermediate-pressure cylinder 104, and the low-pressure cylinder 105 can all enter the evaporator 201 together, as long as the steam in the coal-fired power generation system 1 can meet the requirements of the heat pump power generation system 2.

[0043] In one embodiment, the outlet of the heat source pipeline of the evaporator 201 is connected to the inlet of the second heat exchange passage of the second medium-pressure heat exchanger 114, so that the steam used in the heat source pipeline of the evaporator 201 enters the steam power generation device, at which time the used steam has become liquid.

[0044] In one embodiment, the third steam outlet of the condenser 109 and the low-pressure cylinder 105 is connected to the inlet of the first heat exchange passage of the condenser 109, and the outlet of the first heat exchange passage of the condenser 109 is connected to the inlet of the second low-pressure heat exchanger 116 through the condensate pump 110.

[0045] The outlet of the second low-pressure heat exchanger 116 is connected to the inlet of the first heat exchange passage of the condenser 109. The steam undergoes heat exchange treatment through the condenser 109, allowing the heat of the steam to be used for other purposes. The steam in the condenser 109 is also converted into liquid water and enters the second heat exchange passage of the second low-pressure heat exchanger 116. That is, after the steam in the condenser 109 is in liquid state, it enters the return water pipeline and finally returns to the boiler 101.

[0046] In one embodiment, a third valve 117 is provided between the heat source pipeline of the evaporator 201 and the third steam outlet of the intermediate pressure cylinder 104, and a fourth valve 118 is provided between the outlet of the heat source pipeline of the evaporator 201 and the inlet of the second heat exchange passage of the second intermediate pressure heat exchanger 114.

[0047] In one embodiment, the steam turbine power generation unit further includes a deaerator 107 and a feedwater pump 108; the fourth steam outlet of the intermediate pressure cylinder 104 and the outlet of the first heat exchange passage of the first intermediate pressure heat exchanger 113 are both connected to the inlet of the deaerator 107, the outlet of the second heat exchange passage of the second intermediate pressure heat exchanger 114 is connected to the inlet of the deaerator 107, and the outlet of the deaerator 107 is connected to the inlet of the second heat exchange passage of the first intermediate pressure heat exchanger 113 through the feedwater pump 108. Steam liquefied into water in condenser 109 enters deaerator 107 via second low-pressure heat exchanger 116, first low-pressure heat exchanger 115, and second medium-pressure heat exchanger 114. Steam from first high-pressure heat exchanger 111, second high-pressure heat exchanger 112, and first medium-pressure heat exchanger 113 also enter deaerator 107. Both the water and steam entering deaerator 107 undergo deoxygenation treatment, and the steam entering deaerator 107 is also liquefied into water. Finally, the deoxygenated water from deaerator 107 is pumped into first medium-pressure heat exchanger 114 via feedwater pump 108. In the second heat exchange passage of the second intermediate-pressure heat exchanger 114, the water in the second heat exchange passage passes through the second high-pressure heat exchanger 112 and the first high-pressure heat exchanger 111 and returns to the boiler 101 through the economizer feed port. During the return process, the steam entering the first heat exchange passage of the first high-pressure heat exchanger 111, the steam entering the first heat exchange passage of the second high-pressure heat exchanger 112, and the steam entering the first heat exchange passage of the first intermediate-pressure heat exchanger 113 all exchange heat with the water, thereby increasing the temperature of the water returning to the boiler 101 and indirectly increasing the unit's output power.

[0048] In one embodiment, the output shafts of the high-pressure cylinder 103, the intermediate-pressure cylinder 104, and the low-pressure cylinder 105 are coaxially connected to the input shaft of the generator 106. The coaxial connection enables the high-pressure cylinder 103, the intermediate-pressure cylinder 104, and the low-pressure cylinder 105 to synchronously drive the input shaft of the generator 106 to rotate, thereby increasing the power generation efficiency of the generator 106.

[0049] Operational methods for energy storage processes in integrated coal-fired power generation and heat pump systems with enhanced energy utilization: The third exhaust port of the intermediate-pressure cylinder 104 serves as the starting point for the system's energy storage cycle. At this time, the third valve 117 and the fourth valve 118 open, allowing some steam discharged from the third exhaust port of the intermediate-pressure cylinder 104 to enter the evaporator 201, activating the circulating medium of the heat pump power generation system 2. During the circulation process, the steam transforms into water and finally flows into the second heat exchange passage of the first low-pressure heat exchanger 115. The flow rate of steam entering the evaporator 201 is regulated by the third valve 117 and the fourth valve 118. The compressor 204, turbine, and motor 205 are linked by a gearbox or arranged coaxially. During periods of low electricity demand, the compressor 204, driven by both the turbine and motor 205, compresses the circulating medium, converting the electrical energy output from the coal-fired power plant into the heat energy of the circulating medium. This heat energy is then exchanged with the low-temperature molten salt from the low-temperature molten salt tank 208 via the condenser 206. The resulting high-temperature molten salt flows into the high-temperature molten salt tank 207 via the circulation pump 209, thus achieving the energy storage function.

[0050] Operating methods during the system's energy release process: The high-temperature molten salt tank 207 serves as the starting point for the energy release process. At this time, the first valve 210 and the second valve 211 are closed, and the high-temperature molten salt from the high-temperature molten salt tank 207 flows into the feedwater heat exchanger 102 to heat the water in the return water pipeline, thereby increasing the inlet water temperature of the economizer in the boiler 101. The low-temperature molten salt flowing out of the feedwater heat exchanger 102 flows into the low-temperature molten salt tank 208, thus realizing the energy release function.

[0051] Overall system features and advantages: Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A coal-fired power generation-heat pump integrated power generation system for energy level enhancement and utilization, characterized in that: Including coal-fired power generation systems and heat pump power generation systems; The coal-fired power generation system includes a boiler, a feedwater heat exchanger, and a steam turbine power generation device. The boiler includes a steam outlet, a steam return port, and an economizer feedwater inlet. The steam outlet is connected to the steam inlet of the steam turbine power generation device, the steam return port is connected to the steam outlet of the steam turbine power generation device, and the return water end of the steam turbine power generation device is connected to the economizer feedwater inlet through the first heat exchange passage of the feedwater heat exchanger. The heat pump power generation system includes a turbine generator set, an evaporator, a regenerator, a compressor, a condenser, a motor, a high-temperature heat storage device, and a low-temperature heat storage device. The inlet of the evaporator's heat source pipeline is connected to the steam outlet of the steam turbine generator set, and the outlet of the evaporator's heat source pipeline is connected to the water return end of the steam turbine generator set. The outlet of the evaporator's medium pipeline is connected to the inlet of the first heat exchange passage of the regenerator, and the outlet of the first heat exchange passage of the regenerator is connected to the inlet of the compressor. The outlet of the compressor is connected to the inlet of the medium pipeline of the condenser. The outlet of the medium pipeline is connected to the inlet of the second heat exchange passage of the regenerator, the outlet of the second heat exchange passage of the regenerator is connected to the inlet of the turbine generator set, and the outlet of the turbine generator set is connected to the inlet of the medium pipeline of the evaporator; the outlet of the cold source pipeline of the condenser is connected to the inlet of the high-temperature thermal storage device, the outlet of the high-temperature thermal storage device is connected to the inlet of the second heat exchange passage of the feedwater heat exchanger, the outlet of the second heat exchange passage of the feedwater heat exchanger is connected to the inlet of the low-temperature thermal storage device, and the outlet of the low-temperature thermal storage device is connected to the inlet of the cold source pipeline of the condenser.

2. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 1, characterized in that: The high-temperature thermal storage device uses a high-temperature molten salt tank, and the low-temperature thermal storage device uses a low-temperature molten salt tank.

3. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 2, characterized in that: The heat pump power generation system also includes a circulation pump, and the outlet of the condenser's cold source pipeline is connected to the inlet of the high-temperature molten salt tank through the circulation pump.

4. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 3, characterized in that: A first valve is provided between the inlet of the high-temperature molten salt tank and the circulating pump, and a second valve is provided between the outlet of the low-temperature molten salt tank and the condenser.

5. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 1, characterized in that: The two ends of the compressor's power shaft are coaxially and fixedly connected to the motor shaft of the electric motor and the power shaft of the turbine generator set, respectively.

6. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 1, characterized in that: The steam outlet includes a primary heat steam outlet and a reheat steam outlet; The steam turbine power generation unit includes a high-pressure cylinder, a low-pressure cylinder, an intermediate-pressure cylinder, a high-pressure heat exchanger group, an intermediate-pressure heat exchanger group, a low-pressure heat exchanger group, a generator, a condenser, and a return water pipeline; the high-pressure heat exchanger group includes a first high-pressure heat exchanger and a second high-pressure heat exchanger; the intermediate-pressure heat exchanger group includes a first intermediate-pressure heat exchanger and a second intermediate-pressure heat exchanger; the low-pressure heat exchanger group includes a first low-pressure heat exchanger and a second low-pressure heat exchanger. The primary hot steam outlet is connected to the steam inlet of the high-pressure cylinder, the first steam outlet of the high-pressure cylinder is connected to the inlet of the first heat exchange passage of the second high-pressure heat exchanger and the steam return port, and the second steam outlet of the high-pressure cylinder is connected to the inlet of the first heat exchange passage of the first high-pressure heat exchanger. The reheat steam outlet is connected to the steam inlet of the intermediate-pressure cylinder, the first steam outlet of the intermediate-pressure cylinder is connected to the inlet of the first heat exchange passage of the first intermediate-pressure heat exchanger, the second steam outlet of the intermediate-pressure cylinder is connected to the inlet of the first heat exchange passage of the second intermediate-pressure heat exchanger, the third steam outlet of the intermediate-pressure cylinder is connected to the inlet of the heat source pipeline of the evaporator and the inlet of the low-pressure cylinder respectively, and the outlet of the heat source pipeline inside the evaporator is connected to the return water pipeline of the steam power generation unit. The first steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the first low-pressure heat exchanger, the second steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger, and the third steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger through the condenser. The outlet of the first heat exchange passage of the first high-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the second high-pressure heat exchanger, and the outlet of the first heat exchange passage of the second high-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the first medium-pressure heat exchanger; the outlet of the first heat exchange passage of the second medium-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the first low-pressure heat exchanger, the outlet of the first heat exchange passage of the first low-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the second low-pressure heat exchanger, and the outlet of the first heat exchange passage of the second low-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the condenser. The outlet of the first heat exchange passage of the condenser is connected to the inlet of the second heat exchange passage of the second low-pressure heat exchanger, and the outlet of the second heat exchange passage of the second low-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the first low-pressure heat exchanger; the outlet of the second heat exchange passage of the first low-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the second medium-pressure heat exchanger; the outlet of the first medium-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the second high-pressure heat exchanger, and the outlet of the second heat exchange passage of the second high-pressure heat exchanger is connected to the inlet of the second heat exchange passage of the first high-pressure heat exchanger; the outlet of the second heat exchange passage of the first high-pressure heat exchanger is connected to the inlet of the medium pipeline of the feedwater heat exchanger, and the outlet of the medium pipeline of the feedwater heat exchanger is connected to the return port.

7. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 6, characterized in that: The outlet of the heat source pipeline of the evaporator is connected to the inlet of the second heat exchange passage of the second medium-pressure heat exchanger.

8. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 6, characterized in that: The third steam outlet of the low-pressure cylinder is connected to the inlet of the first heat exchange passage of the condenser, and the outlet of the first heat exchange passage of the condenser is connected to the inlet of the second low-pressure heat exchanger through a condensate pump; the outlet of the second low-pressure heat exchanger is connected to the inlet of the first heat exchange passage of the condenser.

9. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 6, characterized in that: The steam turbine power generation unit also includes a deaerator and a feedwater pump; the fourth steam outlet of the intermediate pressure cylinder and the outlet of the first heat exchange passage of the first intermediate pressure heat exchanger are both connected to the inlet of the deaerator, the outlet of the second heat exchange passage of the second intermediate pressure heat exchanger is connected to the inlet of the deaerator, and the outlet of the deaerator is connected to the inlet of the second heat exchange passage of the first intermediate pressure heat exchanger through the feedwater pump.

10. The coal-fired power generation-heat pump integrated power generation system for energy level enhancement utilization according to claim 6, characterized in that: The output shafts of the high-pressure cylinder, the intermediate-pressure cylinder, the low-pressure cylinder, and the input shaft of the generator are coaxially connected.

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