Integrated phase change heat exchange device and heat exchange method for large-capacity thermal power generating unit

Abstract

The application provides an integrated phase change heat exchange device and heat exchange method for large-capacity thermal power generating units, and relates to the technical field of heat exchange devices. The device comprises mutually connected air inlet parts, multifunctional heat exchange parts, air outlet parts and water outlet parts. The air inlet parts comprise air inlets, first air inlet pipes and second air inlet pipes. The multifunctional heat exchange parts comprise phase change heat exchange systems and heat exchange power generation systems. The phase change heat exchange systems and the heat exchange power generation systems are both provided with water outlets and air outlets. The water outlets are in communication with the water outlet parts, and the air outlets are in communication with the air outlet parts. The phase change heat exchange systems comprise heat exchangers, first condensers and water storage devices which are connected by pipelines, and air release structures. The heat exchange power generation systems comprise second condensers, liquefaction cavities, backflow channels, power generation channels and evaporation channels which are sealed and communicated with each other. The device has the characteristics of good heat exchange effect, multiple functions and low use cost.

Description

Technical Field

[0001] This invention relates to the field of heat exchange device technology, and more specifically, to an integrated phase change heat exchange device and heat exchange method for large-capacity thermal power units. Background Technology

[0002] Integrated phase change heat exchanger systems offer numerous advantages and have significant potential for development and application in large-scale thermal power plants. In low-temperature waste heat recovery projects for large-capacity coal-fired units, phase change heat exchangers can significantly increase the minimum tube wall temperature, reduce or eliminate flue gas acid dew point corrosion, and greatly improve equipment safety. Utilizing the latent heat of vaporization in phase change for heat transfer greatly reduces the mass of the heat transfer medium. Simultaneously, the pressure difference generated by vaporization in the absorber section and condensation in the exothermic section enables automatic flow of the working fluid and zero-power operation, significantly reducing operating costs. Under the current national policy of energy conservation and emission reduction, this product has great prospects for widespread application.

[0003] In existing technologies, integrated phase change heat exchange devices have functional limitations, generally only used for heating water and cooling flue gas. Furthermore, the treatment of non-condensable gases, which affect the overall lifespan and maintenance costs of the device, is prohibitively expensive. Therefore, existing technologies require improvement. Summary of the Invention

[0004] The purpose of this invention is to provide an integrated phase change heat exchange device and heat exchange method for large-capacity thermal power units. It can address the shortcomings of existing technologies, provide solutions, and has the characteristics of good heat exchange effect, diverse functions, and low operating cost.

[0005] The embodiments of the present invention are implemented as follows:

[0006] In a first aspect, the present invention provides an integrated phase change heat exchange device for large-capacity thermal power units, comprising an air inlet, a multi-functional heat exchanger, an air outlet, and a water outlet connected to each other. The air inlet includes an air inlet, a first air inlet pipe, and a second air inlet pipe. The multi-functional heat exchanger includes a phase change heat exchange system and a heat exchange power generation system. One end of the first air inlet pipe is connected to the air inlet, and the other end is connected to the phase change heat exchange system. One end of the second air inlet pipe is connected to the air inlet, and the other end is connected to the heat exchange power generation system. Both the phase change heat exchange system and the heat exchange power generation system are provided with a water outlet and an air outlet. The water outlets are all connected to the water outlet, and the air outlets are all connected to the air outlet.

[0007] The phase change heat exchange system includes a heat exchanger, a first condenser, and a water storage tank connected to each other by pipes. The heat exchanger includes a heat exchange cavity and an evaporation section built into the heat exchange cavity. The two ends of the evaporation section are connected to the condenser and the water storage tank, respectively. The two ends of the heat exchange cavity are connected to the first air inlet and the air outlet, respectively. A venting structure for discharging non-condensable gases is provided above the water storage tank.

[0008] The heat exchange power generation system is a cabin-type structure, including a second condenser, a liquefaction chamber, a reflux channel, a power generation channel, and an evaporation channel that are sealed and connected to each other. The liquefaction chamber is also equipped with a venting structure for discharging non-condensable gases. The reflux channel, the power generation channel, and the evaporation channel are all equipped with heat exchange fluids. The evaporation channel is equipped with a heat exchange structure. The second condenser is built into the liquefaction chamber. The power generation channel is equipped with a water turbine.

[0009] In some embodiments of the present invention, a first air intake pipe is provided with a first electric valve, and a second air intake pipe is provided with a second electric valve. The first electric valve and the second electric valve are linked together, such that the total air intake volume of the first air intake pipe and the second air intake pipe is equal to the air intake volume of the air inlet.

[0010] In some embodiments of the present invention, the bottom of the second condenser is provided as an inclined surface, and the second condenser is disposed at the top of the entire heat exchange power generation system.

[0011] In some embodiments of the present invention, the return channel includes an inclined channel and a vertical channel that are connected to each other. The inclined channel has the same inclination angle as the inclined surface at the bottom of the second condenser, and the inclination angle is set to 30°-45°. The vertical channel is connected to the near end of the power generation channel.

[0012] In some embodiments of the present invention, the power generation channel is inclined, with the inclination angle also set to 30°-45°, and a pressure platform is provided at the far end of the power generation channel where it connects with the evaporation channel. A water pressure sensor is provided on the pressure platform. The evaporation channel is inclined, with the inclination angle being 15°-30° to the left or right of the vertical direction.

[0013] In some embodiments of the present invention, the heat exchange structure includes a lower connecting block, multiple heat exchange pipes and an upper connecting block connected to each other. The number of heat exchange pipes is set to 4-10, and the upper and lower ends of the heat exchange pipes are fixedly and sealed to the upper connecting block and the lower connecting block, respectively. A connecting plate is provided at the lower end of the upper connecting block, and the connecting plate is fixedly and sealed to the second condenser.

[0014] In some embodiments of the present invention, the reflux channel, the power generation channel, and the evaporation channel are interconnected; the second condenser, the reflux channel, the power generation channel, the evaporation channel, and the connecting plate together enclose a liquefaction chamber, the liquefaction chamber is vacuum-sealed, and the connecting plate is provided with a venting structure, a pressure sensor, and a vacuum maintenance port; the liquid level of the heat exchange fluid is lower than the top of the inclined channel and the top of the evaporation channel, and higher than the bottom of the inclined channel and the top of the vertical channel, and the distance between the liquid level and the bottom of the evaporation channel is not less than 50m; the heat exchange fluid is a saturated copper chloride solution.

[0015] In some embodiments of the present invention, the venting structure includes an exhaust pipe and a filter tank. The bottom of the exhaust pipe is inserted into and connected to the liquefaction chamber. A pressure valve or an electrically controlled valve is provided at the bottom and head of the exhaust pipe. Liquid water is provided inside the filter tank. The head of the exhaust pipe is immersed in the liquid water. An outlet is provided at the top of the filter tank, and a valve is provided at the outlet.

[0016] In some embodiments of the present invention, temperature sensors are provided in the air inlet, the first air inlet pipe, the second air inlet pipe, the air outlet, the water outlet, the water inlet, and the water outlet.

[0017] Secondly, the present invention also provides an integrated phase change heat transfer method for large-capacity thermal power units, which, utilizing the aforementioned integrated phase change heat transfer device, includes the following steps:

[0018] S1, the air intake receives the high-temperature gas discharged from the large thermal power plant. Depending on the actual needs, the high-temperature gas can be divided into three destinations: all of it enters the phase change heat exchange system, all of it enters the heat exchange power generation system, or part of it enters the phase change heat exchange system and part of it enters the heat exchange power generation system.

[0019] S2, after entering the phase change heat exchange system, the high-temperature gas enters the heat exchange chamber of the heat exchanger. At this time, the water in the filtrate tank is sent to the evaporation section of the heat exchanger. Due to the high-temperature heat exchange of the gas, the water in the evaporation section will be vaporized into water vapor and sent to the first condenser to liquefy into water. This part of the water flows back to the filtrate tank. At the same time, the high-temperature gas becomes low-temperature gas after passing through the heat exchange of the evaporation section and is sent to the outlet for the next stage of processing. In addition, cold water from the outside will be sent into the first condenser and become hot water after water vapor liquefaction heat exchange. It is then sent to the outlet for circulation or standby.

[0020] S3, when the gas enters the heat exchange power generation system, the high-temperature gas passes through the heat exchange pipes in the heat exchange structure. The heat exchange pipes are immersed in the heat exchange fluid. At this time, due to the high temperature heat exchange, the heat exchange fluid generates bubbles from the bottom. The bubbles rise in the evaporation channel until they rise above the liquid level and burst, becoming steam. After encountering the second condenser, they condense back into liquid and return to the return channel. In this process, due to the heat exchange generating bubbles, the bubbles rise and burst into steam. On the one hand, the increased pressure in the liquefaction chamber squeezes the heat exchange fluid in the return channel, causing it to flow into the evaporation channel. On the other hand, the formation and rising of bubbles also reduce the amount of heat exchange fluid in the evaporation channel. Gravity also causes the heat exchange fluid to flow towards the evaporation channel. Therefore, the power generation channel generates heat exchange fluid flow, which in turn drives the turbine to rotate and drives the external generator to generate electricity.

[0021] In S4, the second condenser also receives external cold water through the steam liquefaction heat exchange in the liquefaction chamber, turning it into hot water, which is then sent to the outlet for circulation or standby. The air outlet above the heat exchange structure is also connected to the air outlet section. The low-temperature flue gas after the high-temperature gas has undergone heat exchange treatment through the heat exchange structure is sent to the outside through the air outlet section for the next stage of treatment.

[0022] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0023] Firstly, the heat exchange effect is excellent. This invention, through both a phase change heat exchange system and a heat exchange power generation system, can cool the large amounts of high-temperature flue gas generated during the coal-fired power generation process in large thermal power plants by exchanging heat with water or other heat exchange fluids. This ensures the flue gas meets the temperature requirements for the next processing stage, such as sending it to an electrostatic precipitator. Additionally, a condenser can be used to liquefy the steam generated during heat exchange for recycling, while simultaneously exchanging heat with cold water to raise its temperature, thus meeting the hot water needs of some plant areas.

[0024] Secondly, the heat exchange function is diverse. In addition to cooling high-temperature hot air and heating cold water, this invention also designs a heat exchange power generation system, which generates the flow and circulation of heat exchange fluid during the heat exchange process, thereby driving the rotation of the water turbine and then driving the generator to generate electricity.

[0025] Thirdly, the operating cost is low. This invention achieves flue gas cooling and cold water heating through heat exchange. The entire multi-functional heat exchange unit is designed in a sealed state, with almost no loss of heat exchange fluid, allowing for long-term cyclical use and reducing costs. In addition, the design of a heat exchange power generation system enables the generation of electricity, further offsetting operating costs. Finally, the design of a low-cost venting structure enables the timely discharge of non-condensable gases, ensuring heat exchange efficiency and reducing equipment operation and maintenance costs. Furthermore, when one part needs maintenance, it can be switched without shutting down, without affecting the normal operation of the entire heat exchange system, reducing maintenance losses and lowering operating costs. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall connection of an embodiment of the present invention;

[0028] Figure 2This is a schematic diagram of the phase change heat transfer system according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of a heat exchange power generation system according to an embodiment of the present invention;

[0030] Figure 4 This is a top view of the connecting plate according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the venting structure in an embodiment of the present invention.

[0032] Icons: 1-Inlet, 2-Multifunctional heat exchanger, 3-Outlet, 4-Water outlet, 5-Inlet, 6-First inlet pipe, 7-Second inlet pipe, 8-Phase change heat exchange system, 9-Heat exchange power generation system, 10-Heat exchanger, 11-First condenser, 12-Water storage tank, 13-Second condenser, 14-Liquefaction chamber, 15-Recirculation channel, 16-Power generation channel, 17-Evaporation channel, 18-Water turbine, 19-Heat exchange fluid, 20-Heat exchange structure, 21-First electric valve, 22-Second electric valve, 23-Inclined surface, 24-Inclined channel, 25-Vertical channel, 26-Connecting plate, 27-Pressure platform, 28-Pressure sensor, 29-Ventilation structure, 30-Pressure sensor, 31-Exhaust pipe, 32-Electric control valve, 33-Filter tank, 34-Vacuum maintenance port. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] Please refer to Figures 1-5 , specifically Figures 1-5 The figure shown is one embodiment of the present invention.

[0037] In a first aspect, this embodiment provides an integrated phase change heat exchange device for large-capacity thermal power units, including an air inlet 1, a multi-functional heat exchanger 2, an air outlet 3, and a water outlet 4 connected to each other. The air inlet 1 includes an air inlet 5, a first air inlet pipe 6, and a second air inlet pipe 7. The multi-functional heat exchanger 2 includes a phase change heat exchange system 8 and a heat exchange power generation system 9. One end of the first air inlet pipe 6 is connected to the air inlet 5, and the other end is connected to the phase change heat exchange system 8. One end of the second air inlet pipe 7 is connected to the air inlet 5, and the other end is connected to the heat exchange power generation system 9. Both the phase change heat exchange system 8 and the heat exchange power generation system 9 are provided with a water outlet and an air outlet. The water outlets are all connected to the water outlet 4, and the air outlets are all connected to the air outlet 3.

[0038] The phase change heat exchange system 8 includes a heat exchanger 10, a first condenser 11, and a water storage tank 12 connected to each other by pipes. The heat exchanger 10 includes a heat exchange cavity and an evaporation section built into the heat exchange cavity. The two ends of the evaporation section are connected to the condenser and the water storage tank 12, respectively. The two ends of the heat exchange cavity are connected to the first air inlet pipe 6 and the air outlet, respectively. An exhaust structure 29 for discharging non-condensable gases is provided above the water storage tank 12.

[0039] The heat exchange power generation system 9 has a cabin-type structure, including a second condenser 13, a liquefaction chamber 14, a return channel 15, a power generation channel 16, and an evaporation channel 17 that are sealed and connected to each other. The liquefaction chamber 14 is also provided with a venting structure 29 for discharging non-condensable gases. The return channel 15, the power generation channel 16, and the evaporation channel 17 are all equipped with heat exchange fluid 19. The evaporation channel 17 is equipped with a heat exchange structure 20. The second condenser 13 is built into the liquefaction chamber 14. The power generation channel 16 is equipped with a water turbine 18.

[0040] It can be concluded that the design of this invention enables the intake section 1 to receive high-temperature gas generated from combustion in a large thermal power plant after power generation; through the coordinated use of the first intake pipe 6 and the second intake pipe 7, this high-temperature gas can be diverted into three directions according to the actual needs of the power plant.

[0041] First, all heat is diverted into the phase change heat exchange system 8. Utilizing the liquid-vapor-liquid phase change of liquid water, the high-temperature gas is cooled, and simultaneously, the source cold water for the condenser is used for heating, ensuring full utilization of heat. This approach applies to two situations within the plant: Firstly, when the heat exchange power generation system 9 requires maintenance, all heat can be diverted into the phase change heat exchange system 8 without affecting the normal high-temperature flue gas cooling of the large thermal power unit or the normal operation of the entire large-cycle treatment system. Secondly, when the plant temporarily does not require additional electrical energy, all heat can be diverted into the phase change heat exchange system 8.

[0042] Secondly, all the gas enters the heat exchange and power generation system 9. This system not only cools the high-temperature flue gas but also heats the cold water. Furthermore, through its compartmentalized structural design, the heat exchange fluid 19 flows using rising steam and gravity, driving the turbine 18 to rotate and power the generator. The generated electricity can be processed and used within the plant or connected to the grid, increasing the value of heat exchange within the plant and reducing operating costs. This represents the majority of practical applications.

[0043] Third, a portion enters the phase change heat exchange system 8, and a portion enters the heat exchange power generation system 9. Similarly, at this time, the plant chooses based on the actual situation, such as when power output is limited, external power processing equipment needs maintenance and cannot be operated at full power, etc., this third option can be selected.

[0044] In summary, this approach enables the simultaneous use of multiple treatment methods for high-temperature flue gas from large generator sets, while also improving heat exchange value and reducing operating costs.

[0045] In one specific embodiment of the present invention, a first electric valve 21 is provided in the first air intake pipe 6, and a second electric valve 22 is provided in the second air intake pipe 7. The first electric valve 21 and the second electric valve 22 are linked together, such that the total air intake volume of the first air intake pipe 6 and the second air intake pipe 7 is equal to the air intake volume of the air intake port 5. This allows for electric control and selection of whether the air enters the phase change heat exchange system 8 or the heat exchange power generation system 9, freeing up manpower and enabling efficient operation.

[0046] In addition, in the specific implementation of this embodiment, the bottom of the second condenser 13 is set as an inclined surface 23, and the second condenser 13 is set at the top of the entire heat exchange power generation system 9. The inclined surface 23 of the second condenser 13 can increase the contact area of ​​the steam during the rising process, improve the heat exchange effect, increase the condensation effect, and improve the heating effect of the cold water in the condenser. The return channel 15 includes an inclined channel 24 and a vertical channel 25 that are connected to each other. The inclined channel 24 has the same inclination angle as the inclined surface 23 at the bottom of the second condenser 13. The inclination angle is set between 30° and 45°. If it is lower than 30 degrees, the downstream flow effect is not good. If it is higher than 45 degrees, the second condenser 13 will be made very tall, increasing the volume of the entire heat exchange power generation system 9 and reducing the direct contact area of ​​the rising steam. In this specific implementation, the solution adopts an angle of 30°.

[0047] It can be seen that the vertical channel 25 is connected to the near end of the power generation channel 16. When the steam reaches the liquefaction chamber 14, it exchanges heat with the second condenser 13, causing it to condense. It then flows down the inclined surface 23 into the inclined channel 24, and subsequently flows back into the vertical channel 25 due to gravity. The power generation channel 16 is inclined at an angle of 30°, and has a certain amount of gravity. This gravity, combined with the gravity of the heat exchange fluid 19 itself and the rising bubbles in the evaporation channel 17, causes the heat exchange fluid 19 to flow in the power generation channel 16. A pressure platform 27 is provided at the far end of the power generation channel 16 where it connects with the evaporation channel 17. A water pressure sensor is installed on the pressure platform 27. The evaporation channel 17 is inclined at an angle of 15° to the left of the vertical direction.

[0048] The pressure platform 27 is designed to facilitate the installation of the heat exchange structure 20 and to allow for the installation of the pressure sensor 28 to accurately measure the pressure at the bottom of the heat exchange fluid 19. The evaporation channel 17 is vertically offset 15° to the left to reduce the overall volume of the heat exchange power generation system 9, thereby reducing costs. It also increases the contact area between the heat exchange pipes of the heat exchange structure 20 and the heat exchange fluid 19, improving the heat exchange effect.

[0049] As shown in the figure, the heat exchange structure 20 includes a lower connecting block, multiple heat exchange pipes, and an upper connecting block (illustrated in the figure but not specifically marked). The upper and lower connecting blocks are used to fix the heat exchange pipes, achieving overall integrity and facilitating installation. There are eight heat exchange pipes, and both ends of each pipe are fixedly and sealed to the upper and lower connecting blocks, respectively. A connecting plate 26 is provided at the lower end of the upper connecting block, and the connecting plate 26 is fixedly and sealed to the second condenser 13. The connecting plate 26 is designed at the top of the entire chamber, serving as a sealing design for the upper end of the heat exchange power generation system 9.

[0050] Those skilled in the art should know that the reflux channel 15, the power generation channel 16, and the evaporation channel 17 are interconnected; the second condenser 13, the reflux channel 15, the power generation channel 16, the evaporation channel 17, and the connecting plate 26 together form a liquefaction chamber 14, which is vacuum-sealed. The connecting plate 26 is equipped with a venting structure 29, a pressure sensor 30, and a vacuum maintenance port 34; the pressure sensor 30 measures the real-time pressure value in the liquefaction chamber 14 and transmits the data to an external display terminal for viewing and monitoring by personnel; the liquid level of the heat exchange fluid 19 is low. The top of the inclined channel 24 and the top of the evaporation channel 17 are higher than the bottom of the inclined channel 24 and the top of the vertical channel 25, and the distance between the liquid level and the bottom of the evaporation channel 17 is designed to be 58m. The most important reason for this setting is to prevent the heat exchange fluid 19 of the evaporation channel 17 and the return channel 15 from being connected in the liquid state. Combined with the design of the inclined channel 24 and the inclined surface 23 of the second condenser 13, the heat exchange fluid 19 of vapor liquefaction will not drip directly onto the evaporation channel 17, but can only drip into the return channel 15, thus avoiding affecting the flow of the heat exchange fluid 19.

[0051] The reason why heat exchange fluid 19 is set as a saturated copper chloride solution is that, compared with liquid water, under the same volume, height, and gravitational acceleration, its density is higher, approximately 1.8 times that of water, and its gravitational potential energy is also increased by 1.8 times. See the table below for details:

[0052] Classification density High liquid level gravitational acceleration water quality water 1000 58 9.8 1000 Saturated copper chloride 1800 58 9.8 1000

[0053] The density unit is kilograms per cubic meter, the liquid level is meters, the gravitational acceleration is meters per second squared, and the mass of water is grams. Therefore, using a saturated copper chloride solution can increase gravitational potential energy, thereby increasing the fluidity and energy carried by the heat exchange fluid 19.

[0054] In this specific implementation, the designed venting structure 29 includes an exhaust pipe 31 and a filter tank 33. The bottom of the exhaust pipe 31 is inserted into and connected to the liquefaction chamber 14. Both the bottom and head of the exhaust pipe 31 are equipped with electrically controlled valves 32. The filter tank 33 contains liquid water, and the head of the exhaust pipe 31 is immersed in the liquid water. The top of the filter tank 33 has an outlet equipped with a valve. When the valve is not open, the internal pressure of the entire venting structure 29 is pre-adjusted to match the pressure of the liquefaction chamber 14.

[0055] In practice, bubbles generated in the evaporation channel 17 rise into the liquefaction chamber 14 and burst, forming steam. During the condensation of the steam in the liquefaction chamber 14, some non-condensable gases may be generated, gradually increasing the pressure in the liquefaction chamber 14. When the pressure sensor 30 detects that the pressure has reached a certain threshold, it opens the electronically controlled valves 32 at the head and tail of the exhaust pipe 31. Since the valve at the top of the filter tank 33 is not open, the pressure in both the exhaust pipe 31 and the filter tank 33 is the same as the pressure in the liquefaction chamber 14 before the pressure increase. Therefore, due to the increase in non-condensable gases, non-condensable gases... The gas rises and is discharged into the liquid water in the filter tank 33, and then into the cavity above the liquid water. At this time, the electric control valves 32 at the head and tail of the exhaust pipe 31 are closed, and the valve at the top of the filter tank 33 is opened. Atmospheric pressure will rush into the filter tank 33, but since the electric control valve 32 at the tail of the exhaust pipe 31 is closed, liquid water will not flow back. After a period of time, the atmospheric pressure in the filter tank 33 is balanced, and the non-condensable gas is discharged normally. Subsequently, a vacuum is drawn again through the outlet so that the pressure above the filter tank 33 reaches the original pressure. Then the valve is closed, and the system waits for the next discharge of non-condensable gas.

[0056] For safety reasons, the valve above the filtrate tank 33 is designed to be two, one electrically controlled and one manually controlled.

[0057] In some embodiments of the present invention, temperature sensors are provided in the air inlet 5, the first air inlet pipe 6, the second air inlet pipe 7, the air outlet, the water outlet, the water inlet, and the water outlet section 4. These sensors enable real-time monitoring of the temperature of the incoming air, the outgoing air, the incoming water, and the outgoing water. They can also be connected to external human-machine interface devices to promptly alarm and notify personnel in case of abnormalities, and to pinpoint the specific location.

[0058] It should also be noted that those skilled in the art should know that the internal pressure of a vacuum space is much lower than the external standard atmospheric pressure (approximately 101 kPa). In this embodiment, the vacuum pressure inside the system is set to 2.02 kPa. The relationship between the boiling point (temperature at which bubbles are generated) and the depth of the entire heat exchange power generation system 9 in the copper chloride solution can be obtained from experimental data in the following table:

[0059] Boiling point ℃ Depth m System pressure Pa 60.5 0.09 20436 92 6.88 72685 100 10.11 116890 120 20.19 213687 141 38.56 389688 150 48.60 495472 158 58.08 589635 163 68.57 786136

[0060] It can be concluded that the vacuum pressure of the liquefaction chamber 14 is 2.02 kPa, while the surface boiling point of the heat exchange fluid 19 is 60°C and the boiling point at a depth of 58 meters (i.e., the bottom of the evaporation channel 17) is 158°C. The temperature of the high-temperature flue gas flowing through the heat exchange pipe in the heat exchange structure 20 is generally above 750°C, which is much higher than the boiling point of the heat exchange fluid 19. Therefore, the conditions for generating bubbles in the evaporation channel 17 can be achieved through heat exchange. The electrically controlled valves 32 at the bottom and top of the exhaust pipe 31 in the venting structure 29 are set to open at a threshold pressure of 2.02 * 105% = 2.121 kPa. Once this threshold is reached, the electrically controlled valves 32 at the bottom and top of the exhaust pipe 31 will open simultaneously (at which time the pressure in the exhaust pipe 31 and the filter tank 33 is also 2.02 kPa), thereby venting the non-condensable gas into the liquid water in the filter tank, and finally to the top of the liquid water. At this point, the electrically controlled valve 32 is closed, and the valve at the top of the filter tank 33 is opened to achieve discharge.

[0061] Secondly, the present invention also provides an integrated phase change heat transfer method for large-capacity thermal power units, which, utilizing the aforementioned integrated phase change heat transfer device, includes the following steps:

[0062] S1, the air intake 1 receives the high-temperature gas discharged from the large thermal power plant. The high-temperature gas can be divided into three destinations according to actual needs: all of it enters the phase change heat exchange system 8, all of it enters the heat exchange power generation system 9, or part of it enters the phase change heat exchange system 8 and part of it enters the heat exchange power generation system 9.

[0063] S2, after entering the phase change heat system 8, the high-temperature gas enters the heat exchange chamber of the heat exchanger 10. At this time, the water in the water tank is sent to the evaporation section of the heat exchanger 10. Due to the high-temperature heat exchange of the high-temperature gas, the water in the evaporation section will be vaporized into water vapor and sent to the first condenser 11 to liquefy into water. This part of the water flows back to the liquid storage tank. At the same time, the high-temperature gas becomes low-temperature gas after passing through the heat exchange of the evaporation section and is sent to the gas outlet for the next stage of processing. In addition, cold water from the outside will be sent into the first condenser 11 and become hot water after water vapor liquefaction heat exchange. It is then sent to the water outlet for circulation or standby.

[0064] S3, after entering the heat exchange power generation system 9, the high-temperature gas passes through the heat exchange pipe in the heat exchange structure 20. The heat exchange pipe is immersed in the heat exchange fluid 19. At this time, due to the high temperature heat exchange, the heat exchange fluid 19 generates bubbles from the bottom. The bubbles rise in the evaporation channel 17 until they rise above the liquid level and burst, becoming steam. After encountering the second condenser 13, they condense back into liquid and return to the return channel 15. In this process, due to the heat exchange generating bubbles, the bubbles rise and burst into steam. On the one hand, the pressure of the liquefaction chamber 14 increases, squeezing the heat exchange fluid 19 in the return channel 15 and causing it to flow into the evaporation channel 17. On the other hand, the formation of bubbles and their rise also reduce the amount of heat exchange fluid 19 in the evaporation channel 17. Gravity also causes the heat exchange fluid 19 to flow towards the evaporation channel 17. Therefore, the power generation channel 16 generates the flow of heat exchange fluid 19, which in turn drives the water turbine 18 to rotate and drives the external generator to generate electricity.

[0065] In S4, in S3, the second condenser 13 also receives external cold water through the steam liquefaction heat exchange in the liquefaction chamber 14, and turns it into hot water, which is then sent to the outlet for circulation or standby. The air outlet above the heat exchange structure 20 is also connected to the air outlet 3. The low-temperature flue gas after the high-temperature gas has undergone heat exchange treatment through the heat exchange structure 20 is sent to the outside through the air outlet 3 for the next stage of treatment.

[0066] In summary, this invention, through both the phase change heat exchange system 8 and the heat exchange power generation system 9, can cool the large amounts of high-temperature flue gas generated during the coal-fired power generation process in large thermal power plants by exchanging heat with water or heat exchange fluid 19, thus meeting the temperature requirements for the next processing stage, such as sending it to an electrostatic precipitator. Additionally, a condenser can be used to liquefy the steam generated during heat exchange for recycling, while simultaneously exchanging heat with cold water to raise its temperature, meeting the needs of some plant areas requiring hot water. Furthermore, besides cooling the high-temperature hot gas and raising the temperature of cold water, this invention also designs the heat exchange power generation system 9 so that the flow and circulation of the heat exchange fluid 19 during the heat exchange process drives the rotation of the turbine 18, which in turn drives the generator to generate electricity. Finally, this invention achieves flue gas cooling and cold water heating through heat exchange. The entire multi-functional heat exchange unit 2 is designed in a sealed state, with almost no loss of the heat exchange fluid 19, allowing for long-term cyclical use and reducing costs. Furthermore, the heat exchange power generation system 9 generates electricity, further offsetting operating costs. Finally, a low-cost venting structure 29 ensures timely discharge of non-condensable gases, guaranteeing heat exchange efficiency and reducing equipment maintenance costs. Additionally, when one component requires maintenance, it can be switched without shutting down the entire heat exchange system, minimizing maintenance losses, reducing operating costs, and extending service life.

[0067] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An integrated phase change heat transfer device for a large capacity thermal power unit, characterized in that, The application relates to a multifunctional heat exchange device, which comprises air inlet parts (1), multifunctional heat exchange parts (2), air outlet parts (3) and water outlet parts (4), the air inlet parts (1) comprise air inlets (5), first air inlet pipes (6) and second air inlet pipes (7), the multifunctional heat exchange parts (2) comprise phase change heat exchange systems (8) and heat exchange power generation systems (9), one end of the first air inlet pipe (6) is communicated with the air inlet (5), and the other end is communicated with the phase change heat exchange system (8), one end of the second air inlet pipe (7) is communicated with the air inlet (5), and the other end is communicated with the heat exchange power generation system (9), the phase change heat exchange system (8) and the heat exchange power generation system (9) are provided with water outlets and air outlets, the water outlets are communicated with the water outlet parts (4), and the air outlets are communicated with the air outlet parts (3). The phase change heat exchange system (8) comprises heat exchangers (10), first condensers (11) and water storage devices (12) which are connected through pipelines, the heat exchanger (10) comprises a heat exchange cavity and an evaporation section which is arranged in the heat exchange cavity, two ends of the evaporation section are communicated with the condenser and the water storage device (12) respectively, two ends of the heat exchange cavity are communicated with the air inlet (5) and the air outlet respectively, and a gas releasing structure (29) is arranged above the water storage device (12). The heat exchange power generation system (9) is in a cabin body type structure and comprises a second condenser (13) and a liquefaction cavity (14), a backflow channel (15), a power generation channel (16) and an evaporation channel (17) which are sealed and communicated with each other, the bottom of the second condenser (13) is provided with an inclined surface (23), the second condenser (13) is arranged at the top of the whole heat exchange power generation system (9), the backflow channel (15) comprises an inclined surface channel (24) and a vertical channel (25) which are communicated with each other, the inclined angle of the inclined surface channel (24) is consistent with that of the inclined surface (23) of the bottom of the second condenser (13), and the vertical channel (25) is communicated with the proximal end of the power generation channel (16), the power generation channel (16) is arranged in an inclined mode, the upper portion of the liquefaction cavity (14) is also provided with a gas releasing structure (29), the backflow channel (15), the power generation channel (16) and the evaporation channel (17) are all arranged with heat exchange fluids (19), the liquid level of the heat exchange fluids (19) is lower than the top end of the inclined surface channel (24) and the top end of the evaporation channel (17), higher than the bottom end of the inclined surface channel (24) and the top end of the vertical channel (25), the heat exchange fluids (19) are saturated copper chloride solutions, the evaporation channel (17) is arranged with a heat exchange structure (20), the second condenser (13) is arranged in the liquefaction cavity (14), and the power generation channel (16) is provided with a water turbine (18).

2. The integrated phase change heat transfer device for large capacity thermal power generating units according to claim 1, characterized in that, The first air inlet pipe (6) is provided with a first electric valve (21), the second air inlet pipe (7) is provided with a second electric valve (22), and the first electric valve (21) and the second electric valve (22) are arranged in linkage with each other, so that the total air inlet amount of the first air inlet pipe (6) and the second air inlet pipe (7) is equal to the air inlet amount of the air inlet (5).

3. The integrated phase change heat transfer device for large capacity thermal power generating units according to claim 2, characterized in that, The slope angle of the slope channel (24) and the slope (23) of the bottom of the second condenser (13) is set to 30-45°.

4. The integrated phase change heat transfer device for large capacity thermal power generating units according to claim 3, characterized in that, The slope angle of the power generation channel (16) is also set to 30-45°, and the distal end of the power generation channel (16) is provided with a pressure platform (27) at the communication position of the evaporation channel (17), the pressure platform (27) is provided with a water pressure sensor, and the evaporation channel (17) is inclined, and the inclination angle is 15-30° to the left or right of the vertical direction.

5. The integrated phase change heat transfer device for large capacity thermal power generating units according to claim 4, characterized in that, The heat exchange structure (20) comprises a lower connecting block, a plurality of heat exchange pipes and an upper connecting block connected with each other, the number of heat exchange pipes is set to 4-10, and the upper and lower ends of the heat exchange pipes are fixedly and sealingly connected with the upper connecting block and the lower connecting block respectively, and the lower end of the upper connecting block is provided with a connecting plate (26) which is fixedly and sealingly connected with the second condenser (13).

6. The integrated phase change heat transfer device for large capacity thermal power generating units according to claim 5, characterized in that, The backflow channel (15), the power generation channel (16) and the evaporation channel (17) are communicated with each other; the second condenser (13), the backflow channel (15), the power generation channel (16), the evaporation channel (17) and the connecting plate (26) jointly enclose a liquefaction cavity (14), the liquefaction cavity (14) is provided with a vacuum, the connecting plate (26) is provided with a gas discharge structure (29), a pressure sensor (30) and a vacuum maintenance opening (34); the liquid level of the heat exchange fluid (19) is not less than 50m from the bottom of the evaporation channel (17).

7. The integrated phase change heat transfer device for large capacity thermal power generating units according to any one of claims 1-6, characterized in that, The gas discharge structure (29) comprises an exhaust pipe (31) and a filtrate tank (33), the bottom of the exhaust pipe (31) is inserted into the liquefaction cavity (14) for communication, the bottom and the head of the exhaust pipe (31) are provided with pressure valves or electric control valves (32), the inside of the filtrate tank (33) is provided with liquid water, the head of the exhaust pipe (31) is immersed in the liquid water, the top of the filtrate tank (33) is provided with an outlet, and the outlet is provided with a valve.

8. The integrated phase change heat transfer device for large capacity thermal power generating units according to claim 1, characterized in that, The air inlet (5), the first air inlet pipe (6), the second air inlet pipe (7), the air outlet, the water outlet, the water inlet and the water outlet part (4) are all provided with temperature sensors.

9. An integrated phase change heat transfer method for large capacity thermal power generating units, using an integrated phase change heat transfer device for large capacity thermal power generating units according to any one of claims 1-8, characterized in that, The method comprises the following steps: S1, the air inlet part (1) receives high-temperature gas discharged from a large thermal power plant, and the high-temperature gas is divided into three directions according to actual needs, all of which enter the phase change heat exchange system (8), all of which enter the heat exchange power generation system (9), or part of which enters the phase change heat exchange system (8) and part of which enters the heat exchange power generation system (9); S2, when entering the phase change heat exchange system (8), the high-temperature gas enters the heat exchange cavity of the heat exchanger (10), at this time, the water in the water storage device (12) is sent to the evaporation section of the heat exchanger (10), at this time, due to the high-temperature heat exchange of the high-temperature gas, the water in the evaporation section is vaporized into water vapor, which is sent to the first condenser (11) to be liquefied into water, and the liquefied water is returned to the water storage device (12); at the same time, the high-temperature gas is changed into low-temperature gas through the heat exchange of the evaporation section, and is sent to the air outlet for the next stage of processing; in addition, the first condenser (11) will send in the cold water from the outside, which is changed into hot water through the heat exchange of the water vapor liquefaction, and is sent to the water outlet for circulation or standby; S3, when entering into the heat exchange power generation system (9), high temperature gas through the heat exchange structure (20) in the heat exchange pipeline, heat exchange pipeline is immersed in the heat exchange fluid (19), at this time the heat exchange fluid (19) due to high temperature heat exchange caused by the bubble from the bottom, bubble in the evaporation channel (17) will rise, until the liquid level surface break, become steam, after the second condenser (13), will be condensed into liquid back to the reflux channel (15); in this process, due to heat exchange produces bubble, bubble rises, break into steam, on the one hand, due to the pressure of the liquefaction cavity (14) increases, extrusion reflux channel (15) in the heat exchange fluid (19), make it flow to the evaporation channel (17), on the other hand, the formation of bubble and rising will also drive the evaporation channel (17) in the heat exchange fluid (19) to reduce, gravity reason also will make the heat exchange fluid (19) flow to the evaporation channel (17) direction, thus the power generation channel (16) produces heat exchange fluid (19) flow, further drive the water turbine (18) rotation, drive the external generator to generate electricity; S4, in S3, the second condenser (13) will also accept the outside cold water through the liquefaction cavity (14) in the steam liquefaction heat exchange, also become hot water, sent to the water outlet circulation or standby; the gas outlet above the heat exchange structure (20) is also communicated with the gas outlet (3), the low temperature flue gas after the heat exchange treatment of high temperature gas through the heat exchange structure (20) is sent to the outside through the gas outlet (3) for the next stage of processing.

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