A waste incineration flue gas waste heat utilization phase change heat exchanger device

Abstract

This invention relates to the field of heat energy recovery equipment technology, and discloses a phase change heat exchanger for utilizing waste heat from waste incineration flue gas, comprising: an upper condensing chamber and a lower evaporating chamber; a steam drum is fixedly installed inside the upper condensing chamber, and a multi-valve linkage mechanism is configured at the top of the steam drum; a straight tube bundle is fixedly installed inside the lower evaporating chamber; the top of the straight tube bundle is connected to the bottom of the steam drum via a condensing downcomer, and the bottom is connected to the side of the steam drum via a steam riser, forming a closed-loop phase change circulation circuit. The circuit is filled with a binary mixed phase change working fluid, and also includes a temperature sensor, an intelligent control module, and a drain valve, with the drain valve electrically connected to the intelligent control module. This invention solves the problems of uneven wall temperature control, easy low-temperature corrosion, low heat transfer efficiency, poor gas-liquid separation effect, narrow operating condition range, insufficient recovery of water vapor condensation heat and "white smoke" emission, and the inability of a single phase change working fluid to adapt to cascade waste heat recovery in existing flue gas waste heat recovery equipment.

Description

Technical Field

[0001] This invention relates to the field of heat energy recovery equipment technology, and in particular to a phase change heat exchanger for utilizing waste heat from waste incineration flue gas. Background Technology

[0002] In the waste heat recovery process of flue gas in power plants, chemical plants, and heating systems, the efficient utilization of medium- and low-temperature flue gas waste heat is key to improving energy efficiency and reducing exhaust losses. Current technologies mainly employ heat pipe phase change heat exchangers and bare tube / finned tube economizers to perform this type of waste heat recovery. Among these, heat pipe phase change heat exchangers are widely used due to their phase change heat transfer characteristics. However, these devices employ a multi-heat pipe assembly design, and manufacturing variations can easily lead to uneven heat pipe wall temperature control. Local wall temperatures below the acid dew point can easily cause low-temperature corrosion, while excessively high wall temperatures reduce heat transfer efficiency. Furthermore, repair costs are high after a single heat pipe is damaged, making overall operation and maintenance difficult. Bare tube and finned tube economizers, on the other hand, suffer from low heat transfer efficiency and complex manufacturing processes. When lowering the exhaust temperature to improve waste heat recovery, they are highly susceptible to sulfuric acid dew point corrosion, severely shortening the equipment's lifespan.

[0003] Meanwhile, existing flue gas waste heat recovery equipment does not fully recover the condensation heat of water vapor in flue gas, resulting in significant "white smoke" emissions in some application scenarios, which does not meet environmental protection requirements. Furthermore, the internal gas-liquid separation of the equipment is poor, and bubbles generated by refrigerant vaporization easily accumulate in the pipeline, significantly reducing the effective heat exchange area. This leads to a narrow range of flue gas parameter conditions that the equipment can adapt to, making it difficult to cope with fluctuations in flue gas parameters from boilers with different loads and fuel types. In addition, traditional phase change heat exchangers mostly use a single phase change working fluid with a fixed phase change temperature range, which cannot adapt to the cascaded waste heat recovery characteristics of medium- and low-temperature flue gas, limiting heat exchange efficiency. Moreover, the pipeline structure design does not consider the flow characteristics of the working fluid, easily leading to problems such as bubble carryover and deterioration of thick liquid film heat transfer, further reducing the waste heat recovery effect. Summary of the Invention

[0004] The present invention aims to provide a phase change heat exchanger device for utilizing waste heat from waste incineration flue gas, in order to solve the problems of uneven wall temperature control, easy low-temperature corrosion, low heat transfer efficiency, poor gas-liquid separation effect, narrow range of applicable operating conditions, insufficient recovery of water vapor condensation heat and "white smoke" emission, and the inability of a single phase change working fluid to adapt to cascade waste heat recovery in existing flue gas waste heat recovery devices.

[0005] To achieve the above objectives, the present invention provides the following method:

[0006] The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas provided by this invention is:

[0007] The device includes: an upper condensing chamber and a lower evaporating chamber;

[0008] The upper condenser chamber is equipped with a steam drum, and the top of the steam drum is equipped with a multi-valve linkage mechanism. The lower evaporator chamber is equipped with a straight tube bundle, the top of the straight tube bundle is connected to the bottom of the steam drum via a condenser downcomer, and the bottom of the straight tube bundle is connected to the side of the steam drum via a steam riser. The steam drum, the condenser downcomer, the straight tube bundle, and the steam riser together form a closed-loop phase change circulation loop. The closed-loop phase change circulation loop is filled with a binary mixed phase change working fluid. The straight tube bundle has a heat transfer enhancement structure. The equipment is also equipped with a temperature sensor and an intelligent control module. The intelligent control module is electrically connected to the temperature sensor and the multi-valve linkage mechanism, respectively. The bottom of the lower evaporator chamber is equipped with a drain valve that communicates with the interior. The drain valve is electrically connected to the intelligent control module.

[0009] Preferably, the multi-valve linkage mechanism is composed of a needle valve, a deflation ball valve, a water injection ball valve, and a hot water meter connected in series along the direction of medium flow. The hot water meter is electrically connected to the intelligent control module. The needle valve, the deflation ball valve, and the water injection ball valve are all electric valves and are electrically connected to the intelligent control module.

[0010] Preferably, the straight tube bundle is arranged in a staggered manner inside the lower evaporator chamber. The upper condenser chamber has a cold water inlet on the upper left and a hot water outlet on the upper right. Both the cold water inlet and the hot water outlet are connected to the interior of the steam drum. The steam drum forms an upper gas phase zone and a lower liquid phase zone in the upper condenser chamber.

[0011] Preferably, the straight tube bundle includes inclined annular ribs arranged around the outside of the straight tube, the angle between the inclined annular ribs and the vertical direction of the straight tube bundle is 30°-45°, and the inclined annular ribs increase the heat transfer area of ​​the straight tube bundle by more than 30% compared with the bare tube.

[0012] Preferably, the straight tube bundle further includes a diameter-grading heat exchange tube assembly and a vapor-liquid separation hood fixed inside the straight tube bundle. The diameter-grading heat exchange tube assembly increases the diameter of the corresponding section of the straight tube bundle in sequence according to the flow direction of the binary mixed phase change working fluid, from the subcooled state to the phase change state to the gaseous state. The vapor-liquid separation hood is fixedly connected inside the straight tube bundle through a connector, dividing the inside of the straight tube bundle into a central liquid phase flow region and a wall-annular gas phase gap region.

[0013] Preferably, the binary mixed phase change working fluid is a mixture of R134a and R245fa, and the mass ratio of R134a to R245fa is 0.4:0.6. The binary mixed phase change working fluid is suitable for heat exchange conditions with an evaporation temperature of 40-50℃ and a condensation temperature of 70-80℃, and is compatible with switching between any auxiliary cooling medium such as air, condensate, and heat transfer oil.

[0014] Preferably, the temperature sensor is installed at least on the metal heated wall surface of the straight tube bundle, at the flue gas inlet of the lower evaporation chamber, and at the flue gas outlet. The intelligent control module controls the valve opening of the multi-valve linkage mechanism according to the real-time feedback signal of the temperature sensor, so as to stabilize the minimum temperature of the metal heated wall surface of the straight tube bundle at 105℃±5℃.

[0015] Preferably, the intelligent control module controls the automatic opening of the venting ball valve during the equipment exhaust stage to discharge non-condensable gases in the closed-loop phase change circulation loop; during the heat exchange stage, it controls the opening degree of the needle valve and the water injection ball valve, and achieves precise control of the steam drum water intake through the flow monitoring of the hot water meter; during the equipment maintenance stage, it controls the periodic opening of the drain valve to discharge impurities deposited in the closed-loop phase change circulation loop.

[0016] Preferably, the equipment has a compact, integrated structure without assembled components. The lower left side of the lower evaporation chamber has a flue gas inlet, and the upper right side has a flue gas outlet. The equipment is directly compatible with the flue gas pipelines of power plant economizers, industrial kilns, and natural gas heating devices, reducing the flue gas exhaust temperature to 100-120℃.

[0017] The beneficial effects of this invention are as follows: 1. High waste heat recovery efficiency, energy saving and environmental protection: Through the stepped heat exchange characteristics of the binary mixed phase change working fluid and the heat transfer enhancement structure design, the recovery efficiency of flue gas sensible heat and water vapor condensation heat is greatly improved, the exhaust temperature can be reduced to 100-120℃, the waste heat utilization rate of the equipment is increased by more than 20% compared with the existing equipment, and the "white smoke elimination" effect of flue gas is achieved, solving the "white smoke" emission problem of traditional equipment and meeting the environmental protection emission requirements.

[0018] 2. Anti-corrosion and anti-dust accumulation, extending equipment life and reducing operation and maintenance costs: The multi-valve linkage mechanism realizes precise closed-loop control of metal wall temperature, avoiding low-temperature corrosion problems at the source. Combined with the self-cleaning characteristics of the 30°-45° inclined annular fins, it effectively reduces dust accumulation. The service life of the equipment is extended to more than 1.5 times that of traditional equipment, the frequency and cost of maintenance are reduced by 40%, and the difficulty of operation and maintenance is greatly reduced.

[0019] 3. Strong operational stability and wide range of adaptability: The integrated closed-loop phase change circulation structure of the upper condenser chamber and lower evaporator chamber solves the problem of uneven wall temperature in traditional heat pipe heat exchangers; the graded pipe diameter design and the setting of the gas-liquid separation hood significantly improve the gas-liquid separation effect of the equipment and avoid bubble accumulation and deterioration of thick liquid film heat transfer; combined with multi-parameter adaptive intelligent control, the equipment can stably cope with the flue gas parameter fluctuations of boilers with different loads and different fuel types, and is adaptable to a wide range of flue gas conditions.

[0020] 4. Compact structure, convenient processing, and easy to promote and apply: The overall structure of the equipment is compact, with no complex assembly parts and simple processing technology. It can be directly adapted and connected to the flue gas pipelines of existing power plant economizers, industrial kilns, and natural gas heating devices without the need for large-scale modification of the original equipment. It is applicable to multiple fields such as power plants, chemical industry, and heating, and has broad engineering promotion value.

[0021] 5. High material utilization and optimized equipment size: The pipe diameter classification design based on the working fluid flow characteristics improves the full tube rate of liquid phase heat transfer, reduces material waste while ensuring heat exchange effect, and optimizes the overall size of the equipment, saving installation space. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0023] Figure 1 A schematic diagram of a phase changer device for utilizing waste heat from waste incineration flue gas, provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of a straight tube bundle structure provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the internal piping structure of a steam drum provided in an embodiment of the present invention.

[0026] Reference numerals: 1-Upper condenser chamber, 2-Lower evaporator chamber, 3-Steam drum, 301-Baffle plate, 302-Heat exchange pipe, 303-Flow control device, 4-Multi-valve linkage mechanism, 401-Needle valve, 402-Ball valve for releasing steam, 403-Water ball valve for filling, 404-Hot water meter, 5-Straight pipe bundle, 501-Inclined annular fin, 502-Vacuum-liquid separation hood, 503-Connector, 6-Condensation downcomer, 7-Steam riser, 8-Drain valve, 9-Cold water inlet, 10-Hot water outlet, 11-Gas phase zone, 12-Liquid phase zone, 13-Flue gas inlet, 14-Flue gas outlet. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or end that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or ends.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the waste heat recovery process of flue gas in power plants, chemical plants, and heating systems, the efficient utilization of medium- and low-temperature flue gas waste heat is key to improving energy efficiency and reducing exhaust losses. Current technologies mainly employ heat pipe phase change heat exchangers and bare tube / finned tube economizers to perform this type of waste heat recovery. Among these, heat pipe phase change heat exchangers are widely used due to their phase change heat transfer characteristics. However, these devices employ a multi-heat pipe assembly design, and manufacturing variations can easily lead to uneven heat pipe wall temperature control. Local wall temperatures below the acid dew point can easily cause low-temperature corrosion, while excessively high wall temperatures reduce heat transfer efficiency. Furthermore, repair costs are high after a single heat pipe is damaged, making overall operation and maintenance difficult. Bare tube and finned tube economizers, on the other hand, suffer from low heat transfer efficiency and complex manufacturing processes. When lowering the exhaust temperature to improve waste heat recovery, they are highly susceptible to sulfuric acid dew point corrosion, severely shortening the equipment's lifespan.

[0031] Meanwhile, existing flue gas waste heat recovery equipment does not fully recover the condensation heat of water vapor in flue gas, resulting in significant "white smoke" emissions in some application scenarios, which does not meet environmental protection requirements. Furthermore, the internal gas-liquid separation of the equipment is poor, and bubbles generated by refrigerant vaporization easily accumulate in the pipeline, significantly reducing the effective heat exchange area. This leads to a narrow range of flue gas parameter conditions that the equipment can adapt to, making it difficult to cope with fluctuations in flue gas parameters from boilers with different loads and fuel types. In addition, traditional phase change heat exchangers mostly use a single phase change working fluid with a fixed phase change temperature range, which cannot adapt to the cascaded waste heat recovery characteristics of medium- and low-temperature flue gas, limiting heat exchange efficiency. Moreover, the pipeline structure design does not consider the flow characteristics of the working fluid, easily leading to problems such as bubble carryover and deterioration of thick liquid film heat transfer, further reducing the waste heat recovery effect.

[0032] The present invention aims to provide a phase change heat exchanger device for utilizing waste heat from waste incineration flue gas, in order to solve the problems of uneven wall temperature control, easy low-temperature corrosion, low heat transfer efficiency, poor gas-liquid separation effect, narrow range of applicable operating conditions, insufficient recovery of water vapor condensation heat and "white smoke" emission, and the inability of a single phase change working fluid to adapt to cascade waste heat recovery in existing flue gas waste heat recovery devices.

[0033] Example 1

[0034] like Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of a phase changer device for utilizing waste heat from waste incineration flue gas, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the straight tube bundle 5 provided in an embodiment of the present invention. A specific embodiment of the present invention provides a phase change heat exchanger device for utilizing waste heat from waste incineration flue gas. The device includes:

[0035] Upper condensing chamber 1 and lower evaporating chamber 2; A steam drum 3 is fixedly installed inside the upper condensing chamber 1, and a multi-valve linkage mechanism 4 is configured at the top of the steam drum 3. The multi-valve linkage mechanism 4 consists of a needle valve 401, a deflation ball valve 402, a water injection ball valve 403, and a hot water meter 404 connected in series along the direction of medium flow. The hot water meter 404 is electrically connected to the intelligent control module. The needle valve 401, deflation ball valve 402, and water injection ball valve 403 are all electric valves and are electrically connected to the intelligent control module; Inside the lower evaporating chamber 2... A straight tube bundle 5 is fixedly installed in the upper evaporator 2. The top of the straight tubes in the straight tube bundle 5 is connected to the bottom of the steam drum 3 via a condenser downcomer 6, and the bottom of the straight tube bundle 5 is connected to the side of the steam drum 3 via a steam riser 7. The steam drum 3, condenser downcomer 6, straight tube bundle 5, and steam riser 7 together form a closed-loop phase change circulation loop. The closed-loop phase change circulation loop is filled with a binary mixed phase change working fluid. The straight tube bundle 5 is a heat transfer enhancement structure and is arranged in a staggered manner inside the lower evaporator 2 and the upper condenser 2. The upper left side of the condenser 1 has a cold water inlet 9 and a hot water outlet 10 on the upper right side. Both the cold water inlet 9 and the hot water outlet 10 are connected to the interior of the steam drum 3. The steam drum 3 forms an upper gas phase zone 11 and a lower liquid phase zone 12 in the upper condenser chamber 1. The straight tube bundle 5 includes inclined annular fins 501 arranged around the outside of the straight tubes. The angle between the inclined annular fins 501 and the vertical direction of the straight tube bundle 5 is 30°-45°. The inclined annular fins 501 increase the heat transfer area of ​​the straight tube bundle 5 compared to the bare tube. The diameter increases by more than 30%; the straight tube bundle 5 also includes a diameter-graded heat exchange tube assembly and a vapor-liquid separation hood 502 fixed inside the straight tube bundle 5. The diameter-graded heat exchange tube assembly increases the diameter of the corresponding section of the straight tube bundle 5 in the order of the supercooled state, phase change state and gaseous state of the binary mixed phase change working fluid along the flow direction of the binary mixed phase change working fluid; the binary mixed phase change working fluid is a mixture of R134a and R245fa, and the mass ratio of R134a to R245fa is 0.4:0.6. The binary mixed phase change working fluid is suitable for heat exchange conditions with an evaporation temperature of 40-50℃ and a condensation temperature of 70-80℃, and is compatible with switching between any auxiliary cooling medium such as air, condensate, and heat transfer oil. The vapor-liquid separation hood 502 is fixedly connected to the inside of the straight tube bundle 5 via a connector 503, dividing the inside of the straight tube bundle 5 into a central liquid phase flow zone and a wall-mounted annular gas phase gap zone. The equipment is also equipped with a temperature sensor and an intelligent control module. The intelligent control module is electrically connected to the temperature sensor and the multi-valve linkage mechanism 4, respectively. A drain valve 8 connected to the inside is fixed at the bottom of the lower evaporation chamber 2 and is electrically connected to the intelligent control module. Temperature sensors are installed at least on the metal heated wall surface of the straight tube bundle 5, at the flue gas inlet 13 of the lower evaporation chamber 2, and at the flue gas outlet 14. The intelligent control module controls the operation based on the real-time feedback signal from the temperature sensor. The valve opening of the multi-valve linkage mechanism 4 stabilizes the minimum temperature of the metal heated wall surface of the straight pipe bundle 5 at 105℃±5℃. During the equipment exhaust stage, the intelligent control module controls the automatic opening of the venting ball valve 402 to discharge non-condensable gases from the closed-loop phase change circulation loop. During the heat exchange stage, it controls the opening of the needle valve 401 and the water injection ball valve 403, achieving precise control of the water inlet of the steam drum 3 through flow monitoring by the hot water meter 404. During equipment maintenance, it controls the periodic opening of the drain valve 8 to discharge impurities deposited in the closed-loop phase change circulation loop. The equipment has a compact, integrated structure with no assembled components. The lower evaporator chamber 2 has a flue gas inlet 13 on the lower left and a flue gas outlet 14 on the upper right. The equipment is directly compatible with the flue gas pipelines of power plant economizers, industrial kilns, and natural gas heating devices, reducing the flue gas exhaust temperature to 100-120℃.

[0036] Example 2:

[0037] like Figure 1-3 As shown, Figure 1 A schematic diagram of a phase changer device for utilizing waste heat from waste incineration flue gas, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the straight tube bundle 5 structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the internal piping structure of the steam drum 3 provided in an embodiment of the present invention. A specific embodiment of the present invention provides a phase change heat exchanger device for utilizing waste incineration flue gas waste heat. The device includes:

[0038] The upper condenser chamber 1 and the lower evaporator chamber 2 are provided. A steam drum 3 is fixedly installed inside the upper condenser chamber 1. A multi-valve linkage mechanism 4 is configured at the top of the steam drum 3. The multi-valve linkage mechanism 4 consists of a needle valve 401, a deflation ball valve 402, a water injection ball valve 403, and a hot water meter 404 connected in series along the direction of medium flow. The hot water meter 404 is electrically connected to the intelligent control module. The needle valve 401, deflation ball valve 402, and water injection ball valve 403 are all electric valves and are electrically connected to the intelligent control module. A straight pipe bundle 5 is fixedly installed inside the lower evaporator chamber 2. The top of the straight pipe in the straight pipe bundle 5 is connected to the bottom of the steam drum 3 via a condenser downcomer 6. The bottom end is connected to the side of the steam drum 3 via the steam riser pipe 7. The steam drum 3, condenser downcomer 6, straight tube bundle 5, and steam riser pipe 7 together form a closed-loop phase change circulation loop. The closed-loop phase change circulation loop is filled with a binary mixed phase change working fluid. The straight tube bundle 5 is a heat transfer enhancement structure and is arranged in a staggered manner inside the lower evaporation chamber 2. The upper condenser chamber 1 has a cold water inlet 9 on the upper left and a hot water outlet 10 on the upper right. Both the cold water inlet 9 and the hot water outlet 10 are connected to the inside of the steam drum 3. The inside of the steam drum 3 consists of several heat exchange pipes 302. The heat exchange pipes 302 are fixedly connected to a device for slowing down the cooling process. The water flow in the heat exchange pipe 302 is guided by a flow guide plate 301 and a flow control device 303. The flow guide plate 301 is fixedly connected to the inner wall of the heat exchange pipe 302. Two flow guide plates 301 are arranged crosswise on the inner wall of the heat exchange pipe 302 as a group. A high-temperature resistant flow control device 303 is fixedly connected in the heat exchange pipe 302 between each group of flow guide plates 301. The flow control device 303 is a filter structure with several through holes. The steam drum 3 forms an upper gas phase zone 11 and a lower liquid phase zone 12 in the upper condensing chamber 1. The straight pipe bundle 5 includes inclined annular ribs 501 arranged around the outside of the straight pipe. The inclined annular ribs 501 are connected to the straight pipe. The included angle of the tube bundle 5 in the vertical direction is 30°-45°. The inclined annular fins 501 increase the heat transfer area of ​​the straight tube bundle 5 by more than 30% compared with the bare tube. The straight tube bundle 5 also includes a tube diameter graded heat exchange tube assembly and a vapor-liquid separation hood 502 fixed inside the straight tube bundle 5. The tube diameter graded heat exchange tube assembly increases the tube diameter of the corresponding section of the straight tube bundle 5 in the order of the supercooled state, phase change state and gaseous state of the binary mixed phase change working fluid along the flow direction of the binary mixed phase change working fluid. The binary mixed phase change working fluid is a mixture of R134a and R245fa, and the mass ratio of R134a to R245fa is 0.4:0.6. The binary mixed phase change working fluid is suitable for heat exchange conditions with an evaporation temperature of 40-50℃ and a condensation temperature of 70-80℃, and is compatible with switching between any auxiliary cooling medium such as air, condensate, and heat transfer oil. The vapor-liquid separation hood 502 is fixedly connected to the inside of the straight tube bundle 5 via a connector 503, dividing the inside of the straight tube bundle 5 into a central liquid phase flow zone and a wall-mounted annular gas phase gap zone. The equipment is also equipped with a temperature sensor and an intelligent control module. The intelligent control module is electrically connected to the temperature sensor and the multi-valve linkage mechanism 4, respectively. A drain valve 8 connected to the inside is fixed at the bottom of the lower evaporation chamber 2 and is electrically connected to the intelligent control module. Temperature sensors are installed at least on the metal heated wall surface of the straight tube bundle 5, at the flue gas inlet 13 of the lower evaporation chamber 2, and at the flue gas outlet 14. The intelligent control module controls the operation based on the real-time feedback signal from the temperature sensor. The valve opening of the multi-valve linkage mechanism 4 stabilizes the minimum temperature of the metal heated wall surface of the straight pipe bundle 5 at 105℃±5℃. During the equipment exhaust stage, the intelligent control module controls the automatic opening of the venting ball valve 402 to discharge non-condensable gases from the closed-loop phase change circulation loop. During the heat exchange stage, it controls the opening of the needle valve 401 and the water injection ball valve 403, achieving precise control of the water inlet of the steam drum 3 through flow monitoring by the hot water meter 404. During equipment maintenance, it controls the periodic opening of the drain valve 8 to discharge impurities deposited in the closed-loop phase change circulation loop. The equipment has a compact, integrated structure with no assembled components. The lower evaporator chamber 2 has a flue gas inlet 13 on the lower left and a flue gas outlet 14 on the upper right. The equipment is directly compatible with the flue gas pipelines of power plant economizers, industrial kilns, and natural gas heating devices, reducing the flue gas exhaust temperature to 100-120℃.

[0039] Implementation process: The flue gas inlet 13 of the equipment is directly connected to the flue gas pipeline of the power plant economizer, industrial kiln, and natural gas heating unit. Then, the flue gas outlet 14 is connected to the subsequent flue gas treatment pipeline. The flue gas passes through the inclined annular fins 501 in the straight tube bundle 5 in the lower evaporation chamber 2, which increases the heat transfer area of ​​the straight tube bundle 5 by more than 30% compared with the bare tube. A vapor-liquid separation hood 502 is installed inside the straight tube bundle 5. By artificially dividing the tubes, the liquid working fluid flows in the central area of ​​the straight tube bundle 5, and the gaseous working fluid concentrates in the annular gap on the straight tube wall to form a thin liquid film heat exchange, which overcomes the limitations of gravity and significantly improves condensation heat transfer. The coefficient is used to solve the problem of heat transfer deterioration caused by thick liquid film; the intelligent control module is electrically connected to the temperature sensor and the multi-valve linkage mechanism 4 respectively; a drain valve 8 connected to the interior is fixed at the bottom of the lower evaporation chamber 2, and the drain valve 8 is electrically connected to the intelligent control module; the temperature sensor is at least arranged on the metal heating wall surface of the straight tube bundle 5, at the flue gas inlet 13 and the flue gas outlet 14 of the lower evaporation chamber 2; the intelligent control module controls the valve opening of the multi-valve linkage mechanism 4 according to the real-time feedback signal of the temperature sensor to stabilize the minimum temperature of the metal heating wall surface of the straight tube bundle 5 at 105℃±5℃; the intelligent control module is designed to... During the exhaust phase, the control valve 402 automatically opens to discharge non-condensable gases from the closed-loop phase change circulation loop. During the heat exchange phase, the opening of the needle valve 401 and the water injection ball valve 403 are controlled, and the flow rate is precisely controlled via the hot water meter 404. During equipment maintenance, the drain valve 8 is periodically opened to discharge impurities deposited in the closed-loop phase change circulation loop. Cold water is introduced through the cold water inlet 9. The cold water is slowed down in the heat exchange pipes 302 of the steam drum 3 by cross-shaped guide plates 301, and then further slowed down by the flow control device 303. After multiple rounds of slowing down, the cold water... The water flow rate in the steam drum 3 is reduced to the slowest level; a closed-loop circulation phase change circuit is formed through the condensate downcomer 6 and the steam riser 7. After being heated by steam in the steam drum 3, the cold water is discharged from the hot water outlet 10. The multi-valve linkage mechanism 4, consisting of a needle valve 401, a deflation ball valve 402, a water injection ball valve 403, and a hot water meter 404 connected in series, monitors the flow rate through the hot water meter 404 to achieve precise control of the water inlet of the steam drum 3. This closed-loop control keeps the minimum temperature of the metal heated wall surface stable at around 105℃, which is higher than the acid dew point temperature to avoid low-temperature corrosion. This enables the utilization of waste heat from the waste incineration flue gas in the entire unit.

[0040] The beneficial effects of this invention are as follows: 1. High waste heat recovery efficiency, energy saving and environmental protection: Through the stepped heat exchange characteristics of the binary mixed phase change working fluid and the heat transfer enhancement structure design, the recovery efficiency of flue gas sensible heat and water vapor condensation heat is greatly improved, the exhaust temperature can be reduced to 100-120℃, the waste heat utilization rate of the equipment is increased by more than 20% compared with the existing equipment, and the "white smoke elimination" effect of flue gas is achieved, solving the "white smoke" emission problem of traditional equipment and meeting the environmental protection emission requirements.

[0041] 2. Anti-corrosion and anti-dust accumulation, extending equipment life and reducing operation and maintenance costs: The multi-valve linkage mechanism realizes precise closed-loop control of metal wall temperature, avoiding low-temperature corrosion problems at the source. Combined with the self-cleaning characteristics of the 30°-45° inclined annular fins, it effectively reduces dust accumulation. The service life of the equipment is extended to more than 1.5 times that of traditional equipment, the frequency and cost of maintenance are reduced by 40%, and the difficulty of operation and maintenance is greatly reduced.

[0042] 3. Strong operational stability and wide range of adaptability: The integrated closed-loop phase change circulation structure of the upper condenser chamber and lower evaporator chamber solves the problem of uneven wall temperature in traditional heat pipe heat exchangers; the graded pipe diameter design and the setting of the gas-liquid separation hood significantly improve the gas-liquid separation effect of the equipment and avoid bubble accumulation and deterioration of thick liquid film heat transfer; combined with multi-parameter adaptive intelligent control, the equipment can stably cope with the flue gas parameter fluctuations of boilers with different loads and different fuel types, and is adaptable to a wide range of flue gas conditions.

[0043] 4. Compact structure, convenient processing, and easy to promote and apply: The overall structure of the equipment is compact, with no complex assembly parts and simple processing technology. It can be directly adapted and connected to the flue gas pipelines of existing power plant economizers, industrial kilns, and natural gas heating devices without the need for large-scale modification of the original equipment. It is applicable to multiple fields such as power plants, chemical industry, and heating, and has broad engineering promotion value.

[0044] 5. High material utilization and optimized equipment size: The pipe diameter classification design based on the working fluid flow characteristics improves the full tube rate of liquid phase heat transfer, reduces material waste while ensuring heat exchange effect, and optimizes the overall size of the equipment, saving installation space.

[0045] The above descriptions are merely embodiments of the present invention. Commonly known technical solutions or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A phase change heat exchanger device for utilizing waste heat from waste incineration flue gas, characterized in that, The device includes: an upper condensing chamber (1) and a lower evaporating chamber (2); The upper condenser chamber (1) is equipped with a steam drum (3) inside. The top of the steam drum (3) is equipped with a multi-valve linkage mechanism (4). The lower evaporator chamber (2) is equipped with a straight pipe bundle (5) inside. The top of the straight pipe in the straight pipe bundle (5) is connected to the bottom of the steam drum (3) via a condenser downcomer (6). The bottom of the straight pipe bundle (5) is connected to the side of the steam drum (3) via a steam riser (7). The steam drum (3), the condenser downcomer (6), and the straight pipe bundle (5) are connected. The steam riser (7) together form a closed-loop phase change circulation loop; the closed-loop phase change circulation loop is filled with a binary mixed phase change working fluid, the straight tube bundle (5) is a heat transfer enhancement structure, the equipment is also equipped with a temperature sensor and an intelligent control module, the intelligent control module is electrically connected to the temperature sensor and the multi-valve linkage mechanism (4) respectively, and the bottom end of the lower evaporation chamber (2) is fixed with a drain valve (8) that communicates with the interior, the drain valve (8) is electrically connected to the intelligent control module.

2. The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The multi-valve linkage mechanism (4) is composed of a needle valve (401), a deflation ball valve (402), a water injection ball valve (403), and a hot water meter (404) connected in series along the direction of medium flow. The hot water meter (404) is electrically connected to the intelligent control module. The needle valve (401), the deflation ball valve (402), and the water injection ball valve (403) are all electric valves and are electrically connected to the intelligent control module.

3. The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The straight tube bundle (5) is arranged in a staggered manner inside the lower evaporation chamber (2). The upper condensation chamber (1) has a cold water inlet (9) on the upper left and a hot water outlet (10) on the upper right. Both the cold water inlet (9) and the hot water outlet (10) are connected to the interior of the steam drum (3). The steam drum (3) forms an upper gas phase zone (11) and a lower liquid phase zone (12) in the upper condensation chamber (1).

4. The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The straight tube bundle (5) includes inclined annular ribs (501) arranged around the outside of the straight tube bundle (5). The angle between the inclined annular ribs (501) and the vertical direction of the straight tube bundle (5) is 30°-45°. The inclined annular ribs (501) increase the heat transfer area of ​​the straight tube bundle (5) by more than 30% compared with the bare tube.

5. The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The straight tube bundle (5) also includes a tube diameter graded heat exchange tube assembly and a vapor-liquid separation hood (502) fixed inside the straight tube bundle (5). The tube diameter graded heat exchange tube assembly increases the tube diameter of the corresponding section of the straight tube bundle (5) in the order of the supercooled state, phase change state and gas state of the binary mixed phase change working fluid along the flow direction of the fluid. The vapor-liquid separation hood (502) is fixedly connected inside the straight tube bundle (5) through a connector (503), dividing the inside of the straight tube bundle (5) into a central liquid phase flow zone and a wall annular gas phase gap zone.

6. The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The binary mixed phase change working fluid is a mixture of R134a and R245fa, with a mass ratio of R134a to R245fa of 0.4:0.

6. The binary mixed phase change working fluid is suitable for heat exchange conditions with an evaporation temperature of 40-50℃ and a condensation temperature of 70-80℃, and is compatible with switching between any auxiliary cooling medium, such as air, condensate, or heat transfer oil.

7. The phase change heat exchanger device for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The temperature sensor is installed at least on the metal heated wall surface of the straight tube bundle (5), at the flue gas inlet (13) and the flue gas outlet (14) of the lower evaporation chamber (2). The intelligent control module controls the valve opening of the multi-valve linkage mechanism (4) according to the real-time feedback signal of the temperature sensor, so as to stabilize the minimum temperature of the metal heated wall surface of the straight tube bundle (5) at 105℃±5℃.

8. A phase change heat exchanger for utilizing waste heat from waste incineration flue gas according to claim 7, characterized in that: The intelligent control module controls the automatic opening of the deflation ball valve (402) during the equipment exhaust stage to discharge non-condensable gases in the closed-loop phase change circulation loop; during the heat exchange stage, it controls the opening degree of the needle valve (401) and the water injection ball valve (403) and achieves precise control of the water intake of the steam drum (3) through the flow monitoring of the hot water meter (404); during the equipment maintenance stage, it controls the periodic opening of the drain valve (8) to discharge impurities deposited in the closed-loop phase change circulation loop.

9. A phase change heat exchanger for utilizing waste heat from waste incineration flue gas according to claim 1, characterized in that: The equipment is a compact integrated structure with no assembled parts. The lower evaporation chamber (2) has a flue gas inlet (13) on the lower left and a flue gas outlet (14) on the upper right. The equipment is directly adapted to the flue gas pipeline of the power plant economizer, industrial kiln, and natural gas heating device to reduce the flue gas exhaust temperature to 100-120℃.

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