Gas-fired boiler flue gas waste heat recovery device and method thereof

Abstract

The invention discloses a gas-fired boiler flue gas waste heat recovery device and method. The gas-fired boiler flue gas waste heat recovery device comprises a waste heat recovery assembly, and the waste heat recovery assembly comprises a recovery box, a communicating pipe, a driving motor, a transmission rod, a transmission gear, a rotating disc, a gear ring, a stirring plate and a mounting shaft; and a first heat exchange chamber, a second heat exchange chamber and a third heat exchange chamber are formed in the recycling box. Water in the first heat exchange chamber exchanges heat with high-temperature flue gas in the first heat exchange pipe, the temperature of a water source in the first heat exchange chamber rapidly rises, and then a water source in the second heat exchange chamber and a water source in the third heat exchange chamber exchange heat with the flue gas; by arranging the three heat exchange pipes and the three heat exchange chambers, circulation of a water source is achieved through the conveying pump, under the condition that a heat pump is not added, the waste heat recovery efficiency of smoke can be improved, by arranging the water source stirring mechanism, the water source can make full contact with the heat exchange pipes, and then the heat exchange effect of the heat exchange pipes is improved.

Description

Technical Field

[0001] The present invention relates to a waste heat recovery device and method thereof, specifically a waste heat recovery device and method for the flue gas of a gas boiler, belonging to the technical field of waste heat recovery of gas boilers. Background Art

[0002] When a gas boiler operates, high-temperature flue gas is generated because gas (such as natural gas, liquefied petroleum gas, etc.) is mixed with air in the burner of the boiler and then ignited, resulting in a violent combustion reaction. During the combustion process, the chemical energy in the gas is rapidly converted into heat energy, causing the temperature of the combustion products to rise sharply, forming high-temperature flue gas. These high-temperature flue gases contain carbon dioxide, water vapor, nitrogen, and small amounts of carbon monoxide, sulfur dioxide and other gases generated by combustion, and their temperature can usually reach several hundred degrees Celsius or even higher, and then are discharged from the boiler system through the chimney. These flue gases are usually directly discharged into the atmosphere, not only causing waste of energy, but also possibly causing thermal pollution to the environment. A waste heat recovery device can capture the heat in the flue gas and convert it into usable heat energy for heating domestic hot water, heating, preheating boiler feed water, etc., thereby improving energy utilization efficiency, reducing energy consumption and operating costs.

[0003] A waste heat recovery device can capture the heat in the flue gas and convert it into usable heat energy for heating domestic hot water, heating, preheating boiler feed water, etc., thereby improving energy utilization efficiency, reducing energy consumption and operating costs. The device mainly works based on the heat exchange principle. It usually includes one or more heat exchangers. When high-temperature flue gas passes through the heat exchanger, the heat is transferred through the wall of the heat exchanger to the medium on the other side, such as cold water or boiler feed water.

[0004] It is known that the Chinese authorized utility model (publication number: CN222503817U) discloses a deep waste heat recovery system for the flue gas of a gas boiler, which returns the low-temperature water flowing back from the heat supply terminal during the working process to the compression heat pump, preheats the low-temperature water through the compression heat pump and the sewage waste heat recovery device, and the preheated water then enters the gas boiler through the return valve group. After being preheated, the water enters the gas boiler to heat it. During the whole process, since the starting temperature of the water entering the gas boiler is preheated, the heating efficiency is significantly improved; During the process of flue gas waste heat recovery, although the effective preheating of low-temperature water is achieved through a compression heat pump, during the process of using the compression heat pump to preheat the low-temperature water, the overall energy consumption of the entire system increases. This is because the operation of the compression heat pump requires consuming additional electrical energy to drive the compressor to work. During the operation of the compressor, electrical energy is converted into mechanical energy, and then the heat transfer is realized. The consumption of this part of electrical energy is additional energy input. Although a certain amount of heat can be obtained from the low-temperature heat source through the action of the heat pump, considering the input electrical energy and the operating conditions of the entire system comprehensively, it ultimately leads to an increase in overall energy consumption. Therefore, a flue gas waste heat recovery device and method for a gas boiler are proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a flue gas waste heat recovery device and method for a gas boiler to solve one of the problems proposed in the above background technology.

[0006] The present invention is implemented by the following technical solutions: A flue gas waste heat recovery device for a gas boiler includes a waste heat recovery component. The waste heat recovery component includes a recovery tank, a connecting pipe, a driving motor, a transmission rod, a transmission gear, a turntable, a toothed ring, a stirring plate, and a mounting shaft. A first heat exchange chamber, a second heat exchange chamber, and a third heat exchange chamber are opened inside the recovery tank. A first heat exchange pipe, a second heat exchange pipe, and a third heat exchange pipe are respectively installed inside the first heat exchange chamber, the second heat exchange chamber, and the third heat exchange chamber. The two connecting pipes are respectively installed inside the second heat exchange chamber and the third heat exchange chamber. A delivery pump is installed on the connecting pipe. One end of the transmission rod is fixedly connected to the output shaft of the driving motor. The transmission gear is fixedly connected to the outer side wall of the transmission rod. The toothed ring is fixedly connected to the outer side wall of the turntable. The turntable is rotationally connected to the inside of the recovery tank through the mounting shaft. The stirring plate is installed on one side of the turntable.

[0007] As a further preference of this technical solution: The air outlet of the first heat exchange pipe is communicated with the air inlet of the second heat exchange pipe, and the air outlet of the second heat exchange pipe is communicated with the air inlet of the third heat exchange pipe.

[0008] As a further preference of this technical solution: One end of one connecting pipe is communicated with the first heat exchange chamber and the second heat exchange chamber respectively, and one end of the other connecting pipe is communicated with the second heat exchange chamber and the third heat exchange chamber respectively. The delivery pump is installed on the upper surface of the recovery tank.

[0009] As a further preference of this technical solution: Two turntables are symmetrically arranged outside the first heat exchange pipe, the second heat exchange pipe, and the third heat exchange pipe. The transmission rod is rotationally connected to the inside of the recovery tank. The driving motor is installed on one side of the recovery tank. The outer side wall of the toothed ring is meshed with the outer side wall of the transmission gear.

[0010] As a further preference of this technical solution: a water inlet pipe is installed on the upper surface of the recovery tank, the position of the water inlet pipe corresponds to the position of the third heat exchange chamber, a water outlet pipe is installed at the bottom of the front surface of the recovery tank, and the position of the water outlet pipe corresponds to the position of the first heat exchange chamber.

[0011] As a further preference of this technical solution: a filtering assembly is arranged outside the recovery tank, and the filtering assembly includes a smoke inlet pipe, a shunt pipe, an installation cover, a housing, a dust exhaust pipe, a connecting pipe, a filter cartridge, a rotating shaft, two scraping plates and a pushing blade; One end of the smoke inlet pipe is communicated with the top end of the housing, one end of the shunt pipe is communicated with the smoke inlet pipe, the other end of the shunt pipe is communicated with the installation cover, the installation cover is fixedly connected to the lower surface of the housing, the connecting pipe is installed on the outer side wall of the housing and communicated with the housing, the filter cartridge is installed inside the housing, the dust exhaust pipe is installed at the top end of the housing, the two scraping plates are symmetrically and fixedly connected to the outer side wall of the rotating shaft, the rotating shaft is rotatably connected to the inside of the housing, the pushing blade is fixedly connected to the bottom of the outer side wall of the rotating shaft, and electromagnetic valves are installed on the smoke inlet pipe, the shunt pipe, the dust exhaust pipe and the connecting pipe.

[0012] As a further preference of this technical solution: an air inlet hole is opened on the lower surface of the housing, and the installation cover is communicated with the housing through the air inlet hole.

[0013] As a further preference of this technical solution: the scraping plate is located inside the filter cartridge, the scraping plate is attached to the inner side wall of the filter cartridge, and the pushing blade is located inside the installation cover.

[0014] As a further preference of this technical solution: the end of the connecting pipe away from the housing is communicated with the air inlet of the first heat exchange pipe, and a smoke exhaust pipe is installed at the air outlet of the third heat exchange pipe.

[0015] A method for recovering the waste heat of the flue gas of a gas boiler includes the following steps: Pre-filtering of flue gas: The high-temperature flue gas of the gas boiler flows into the housing from the smoke inlet pipe. After the dust impurities in the flue gas are filtered by the filter cartridge, the flue gas flows into the first heat exchange pipe; Waste heat recovery: The water in the first heat exchange chamber exchanges heat with the high-temperature flue gas in the first heat exchange pipe, the temperature of the high-temperature flue gas decreases, and the temperature of the water source in the first heat exchange chamber increases; Primary preheating of the water source: The flue gas in the first heat exchange pipe flows into the second heat exchange pipe and exchanges heat with the water source in the second heat exchange chamber, and the water source in the second heat exchange chamber is preheated; Secondary preheating of the water source: The flue gas in the second heat exchange pipe flows into the third heat exchange pipe and exchanges heat with the water source in the third heat exchange chamber, and the water source in the third heat exchange chamber is preheated. At this time, the temperature of the water source in the first heat exchange chamber is the highest, and the temperature of the water source in the third heat exchange chamber is the lowest; Preheated water circulation: Under the transportation of the delivery pump and the connecting pipe, the preheated water in the third heat exchange chamber flows into the second heat exchange chamber, the preheated water in the second heat exchange chamber flows into the first heat exchange chamber, and the water source in the first heat exchange chamber is discharged from the water outlet pipe; Full heat exchange: The driving motor drives the transmission rod, and the transmission rod transmits power through the transmission gear and the gear ring. The stirring plate stirs the flow of the water source to accelerate heat exchange.

[0016] Advantages of the present invention: In the present invention, heat exchange is generated between the water in the first heat exchange chamber and the high-temperature flue gas in the first heat exchange tube. Since the temperature of the high-temperature flue gas is the highest at this time, the temperature of the water source in the first heat exchange chamber rises rapidly. Then, the water sources in the second heat exchange chamber and the third heat exchange chamber exchange heat with the flue gas. By using the delivery pump to transport the water source in the second heat exchange chamber to the first heat exchange chamber, the initial water temperature in the first heat exchange chamber can be increased. After heat exchange, the water temperature in the first heat exchange chamber can be higher, thereby effectively improving the recovery efficiency of the flue gas waste heat; Compared with the prior art, the present invention improves the recovery efficiency of the flue gas waste heat and reduces energy consumption without increasing the heat pump by setting three heat exchange tubes and three heat exchange chambers and realizing the circulation of the water source through the delivery pump. Moreover, by setting the water source stirring mechanism, the water source can be in full contact with the heat exchange tube, thereby improving the heat exchange effect of the heat exchange tube. Description of the drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a flue gas waste heat recovery device for a gas boiler according to the present invention; Figure 2 It is a schematic structural diagram of the waste heat recovery component of the present invention; Figure 3 It is a schematic structural diagram of the stirring plate of the present invention; Figure 4 It is a schematic connection diagram of three heat exchange tubes of the present invention; Figure 5 It is a schematic structural diagram of the recovery box of the present invention; Figure 6 It is a schematic structural diagram of the filtering component of the present invention; Figure 7 It is a schematic structural diagram of the pushing blade of the present invention; Figure 8 It is a schematic structural diagram of the outer shell of the present invention.

[0019] In the figure: 101, waste heat recovery component; 11, recovery tank; 12, connecting pipe; 13, delivery pump; 14, drive motor; 15, first heat exchange chamber; 16, second heat exchange chamber; 17, third heat exchange chamber; 18, transmission rod; 19, transmission gear; 20, turntable; 21, gear ring; 22, stirring plate; 23, mounting shaft; 24, first heat exchange pipe; 25, second heat exchange pipe; 26, third heat exchange pipe; 27, water inlet pipe; 28, water outlet pipe; 29, smoke exhaust pipe; 301, filtration component; 31, smoke inlet pipe; 32, shunt pipe; 33, mounting cover; 34, outer shell; 35, dust exhaust pipe; 36, connecting pipe; 37, solenoid valve; 38, filter cartridge; 39, rotating shaft; 40, scraping plate; 41, pushing blade; 42, air inlet hole. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Embodiment Please refer to Figures 1 - 8 , the present invention provides a technical solution: a gas boiler flue gas waste heat recovery device, including a waste heat recovery component 101, and the waste heat recovery component 101 includes a recovery tank 11, a connecting pipe 12, a drive motor 14, a transmission rod 18, a transmission gear 19, a turntable 20, a gear ring 21, a stirring plate 22 and a mounting shaft 23; The inside of the recovery tank 11 is provided with a first heat exchange chamber 15, a second heat exchange chamber 16 and a third heat exchange chamber 17. The first heat exchange chamber 15, the second heat exchange chamber 16 and the third heat exchange chamber 17 are respectively installed with a first heat exchange pipe 24, a second heat exchange pipe 25 and a third heat exchange pipe 26. During the heat exchange process, the water in the first heat exchange chamber 15 exchanges heat with the high-temperature flue gas in the first heat exchange pipe 24. Since the temperature of the high-temperature flue gas is the highest at this time, the temperature of the water source in the first heat exchange chamber 15 rises rapidly. After the heat exchange, the temperature of the flue gas decreases, but there is still a large amount of waste heat. Then the flue gas in the first heat exchange pipe 24 flows into the second heat exchange pipe 25 and exchanges heat with the water source in the second heat exchange chamber 16. At this time, the temperature of the high-temperature flue gas decreases, and the water source in the second heat exchange chamber 16 is preheated. Then the flue gas in the second heat exchange pipe 25 flows into the third heat exchange pipe 26 and exchanges heat with the water source in the third heat exchange chamber 17. The water source in the third heat exchange chamber 17 is preheated, and the temperature of the flue gas drops to the lowest and can be directly discharged. At this time, among the three heat exchange chambers, the temperature of the water source in the first heat exchange chamber 15 is the highest, and the temperature of the water source in the third heat exchange chamber 17 is the lowest; through the cooperation of the three heat exchange chambers and the heat exchange pipes, three times of heat exchange of the flue gas can be realized, improving the recovery efficiency of the flue gas waste heat; Two connecting pipes 12 are respectively installed inside the second heat exchange chamber 16 and the third heat exchange chamber 17. A delivery pump 13 is installed on the connecting pipe 12. Both ends of one connecting pipe 12 are respectively communicated with the first heat exchange chamber 15 and the second heat exchange chamber 16, and both ends of the other connecting pipe 12 are respectively communicated with the second heat exchange chamber 16 and the third heat exchange chamber 17. The delivery pump 13 is installed on the upper surface of the recovery tank 11. Then, under the delivery of the delivery pump 13, the preheated water source in the third heat exchange chamber 17 flows into the second heat exchange chamber 16. Since the water source in the third heat exchange chamber 17 has been preheated, the initial temperature of the water source during heat exchange in the second heat exchange chamber 16 can be increased, thereby increasing the water temperature in the second heat exchange chamber 16. Similarly, by using the delivery pump 13 to deliver the water source in the second heat exchange chamber 16 to the first heat exchange chamber 15, the initial water temperature during heat exchange in the first heat exchange chamber 15 can be increased. After heat exchange, the water temperature in the first heat exchange chamber 15 can be made higher, thereby effectively improving the recovery efficiency of the waste heat of the flue gas; One end of the transmission rod 18 is fixedly connected to the output shaft of the drive motor 14. The transmission gear 19 is fixedly connected to the outer side wall of the transmission rod 18. The toothed ring 21 is fixedly connected to the outer side wall of the turntable 20. The turntable 20 is rotationally connected to the inside of the recovery tank 11 through the mounting shaft 23. The stirring plate 22 is installed on one side of the turntable 20. Two turntables 20 are symmetrically arranged outside the first heat exchange tube 24, the second heat exchange tube 25, and the third heat exchange tube 26. The transmission rod 18 is rotationally connected to the inside of the recovery tank 11. The drive motor 14 is installed on one side of the recovery tank 11. The outer side wall of the toothed ring 21 is meshed with the outer side wall of the transmission gear 19. By driving the transmission rod 18 to rotate through the drive motor 14, the transmission rod 18 drives the transmission gear 19, the transmission gear 19 drives the toothed ring 21 through the teeth, the toothed ring 21 drives the turntable 20 to rotate, and the turntable 20 drives the stirring plate 22. The stirring plate 22 stirs the water sources in the three heat exchange chambers respectively, so that the water source can be in full contact with the heat exchange tube to improve the heat exchange effect.

[0022] In this embodiment, specifically: the air outlet of the first heat exchange tube 24 is communicated with the air inlet of the second heat exchange tube 25, and the air outlet of the second heat exchange tube 25 is communicated with the air inlet of the third heat exchange tube 26, so as to ensure the circulation of the flue gas.

[0023] In this embodiment, specifically: a water inlet pipe 27 is installed on the upper surface of the recovery tank 11. The position of the water inlet pipe 27 corresponds to the position of the third heat exchange chamber 17. Cold water can be continuously injected into the third heat exchange chamber 17 through the water inlet pipe 27 to recover the waste heat of the flue gas; A water outlet pipe 28 is installed at the bottom of the front surface of the recovery tank 11. The position of the water outlet pipe 28 corresponds to the position of the first heat exchange chamber 15. The hot water in the first heat exchange chamber 15 can be discharged through the water outlet pipe 28.

[0024] In this embodiment, specifically, a filtering component 301 is arranged outside the recycling bin 11. The filtering component 301 is used to filter the impurity particles in the flue gas, so as to prevent the impurity particles from adhering to the inside of the heat exchange tube and affecting the heat exchange effect. During the operation of the gas boiler, various impurity particles will inevitably be mixed in the high-temperature flue gas. The sources of these impurity particles are relatively diverse. They may be carbon black particles generated by incomplete combustion of the gas, or dust particles entering the boiler with the air. If the impurity particles in the high-temperature flue gas are not effectively treated, when the flue gas flows in the heat exchange system, the impurity particles will move forward along with the flow direction of the flue gas and then flow into the heat exchange tube. Once the impurity particles enter the heat exchange tube, they will gradually accumulate on the inner wall of the heat exchange tube. Over time, more and more accumulated impurity particles will form a hindrance layer. This hindrance layer will seriously affect the heat exchange effect of the heat exchange tube, resulting in a significant reduction in the heat exchange efficiency.

[0025] The filtering component 301 includes a smoke inlet pipe 31, a shunt pipe 32, a mounting cover 33, a housing 34, a dust discharge pipe 35, a connecting pipe 36, a filter cartridge 38, a rotating shaft 39, two scraping plates 40 and a pushing blade 41. One end of the smoke inlet pipe 31 is communicated with the top end of the housing 34. One end of the shunt pipe 32 is communicated with the smoke inlet pipe 31, and the other end of the shunt pipe 32 is communicated with the mounting cover 33. The mounting cover 33 is fixedly connected to the lower surface of the housing 34. The connecting pipe 36 is installed on the outer side wall of the housing 34 and is communicated with the housing 34. The filter cartridge 38 is installed inside the housing 34. The end of the connecting pipe 36 far from the housing 34 is communicated with the air inlet of the first heat exchange tube 24. During waste heat recovery, the flue gas of the gas boiler flows into the smoke inlet pipe 31, then flows into the housing 34 through the smoke inlet pipe 31, and the impurity particles in the flue gas are filtered by the filter cartridge 38. Then the high-temperature flue gas flows into the first heat exchange tube 24 through the connecting pipe 36. By filtering the impurity particles in the high-temperature flue gas of the gas boiler, it is possible to prevent the impurity particles from flowing into the heat exchange tube and accumulating to affect the heat exchange effect of the heat exchange tube. The dust discharge pipe 35 is installed at the top end of the housing 34. The two scraping plates 40 are symmetrically and fixedly connected to the outer side wall of the rotating shaft 39. The rotating shaft 39 is rotatably connected to the inside of the housing 34. The pushing blade 41 is fixedly connected to the bottom of the outer side wall of the rotating shaft 39. When the flue gas flows into the inside of the mounting cover 33, the flue gas drives the pushing blade 41 to rotate. The pushing blade 41 drives the rotating shaft 39 to rotate, and the rotating shaft 39 drives the scraping plates 40. The impurity particles filtered by the filter cartridge 38 can be cleaned by the scraping plates 40 and then discharged through the dust discharge pipe 35. Solenoid valves 37 are installed on the smoke inlet pipe 31, the shunt pipe 32, the dust exhaust pipe 35 and the connecting pipe 36. An air inlet hole 42 is formed in the lower surface of the housing 34. The mounting cover 33 communicates with the housing 34 through the air inlet hole 42. The scraping plate 40 is located inside the filter cartridge 38. The scraping plate 40 is attached to the inner side wall of the filter cartridge 38. The pushing blade 41 is located inside the mounting cover 33. After the filter assembly 301 operates for a period of time, the filter cartridge 38 needs to be cleaned to prevent the filter cartridge 38 from being blocked; When cleaning the filter cartridge 38, control the solenoid valve 37 on the smoke inlet pipe 31 to close, the solenoid valve 37 on the shunt pipe 32 to open, the solenoid valve 37 on the dust exhaust pipe 35 to open, and the solenoid valve 37 on the connecting pipe 36 to close; At this time, the flue gas flows into the mounting cover 33 through the shunt pipe 32, then flows into the housing 34 through the air inlet hole 42, and finally is discharged through the dust exhaust pipe 35. During this process, the flue gas drives the pushing blade 41 to rotate. The pushing blade 41 drives the rotating shaft 39 to rotate. The rotating shaft 39 drives the scraping plate 40. The impurities filtered on the inner wall of the filter cartridge 38 are cleaned by the scraping plate 40 and then discharged through the dust exhaust pipe 35 under the drive of the flue gas, thereby realizing the reverse blowing and scraping cleaning of the filter cartridge 38.

[0026] In this embodiment, specifically: an air flow sensor is installed on the connecting pipe 36 to monitor the flow rate of the flue gas, and then the monitoring data is sent to the control system in real time. The control system judges whether the filter cartridge 38 is blocked according to the flow rate algorithm in combination with the working state of the gas furnace and the flue gas flow rate; The flow rate algorithm includes the following steps: Initial data recording: When the gas boiler is operating normally and the filter cartridge 38 is in a normal state, the flue gas flow rate data for a period of time (such as one week) is continuously collected through the air flow sensor on the connecting pipe 36. These data are used as reference data, and the corresponding normal flue gas flow rate ranges under different working conditions (such as different gas supply amounts, different boiler loads) are recorded; at the same time, the working state parameters of the gas furnace at this time, such as gas flow rate, number of burners turned on, boiler pressure, etc., are recorded and a corresponding relationship is established with the flue gas flow rate data; Real-time data acquisition: During the operation of the boiler, the air flow sensor continuously collects the current flue gas flow rate data and synchronously obtains the current working state parameters of the gas furnace, such as the current gas flow rate, the working mode of the burner, etc.; Working condition matching: According to the working state parameters of the gas furnace obtained in real time, find the matching working condition in the previously recorded reference data. For example, if the current gas flow rate is a certain specific value and the number of burners turned on is a certain number, find the normal flue gas flow rate range under the same or similar working conditions in the reference data; Flow comparison: Compare the flue gas flow rate collected in real time with the normal flue gas flow rate range under the matching operating conditions to determine whether the real-time flow rate is within the normal range. If the real-time flow rate is within the normal range, it is considered that the filter cartridge 38 is not currently blocked, and real-time monitoring continues; Trend analysis: If the real-time flow rate is lower than the normal range, further analyze the change trend of the flow rate. Check the flue gas flow rate data in a recent period of time (such as the past 1 hour) to determine whether the flow rate shows a continuous downward trend; if the flow rate is only occasionally lower than the normal range, but the overall trend is stable, it may be caused by some temporary factors, such as a short-term fluctuation in gas supply, etc. At this time, it is not determined that the filter cartridge 38 is blocked; if the flow rate continues to decline and the decline amplitude exceeds a certain threshold (set according to the actual situation, such as 10% of the normal flow rate), it is initially judged that the filter cartridge 38 may be blocked.

[0027] In this embodiment, specifically: A smoke exhaust pipe 29 is installed at the air outlet of the third heat exchange pipe 26, and through the smoke exhaust pipe 29, the flue gas after heat exchange can be discharged from the third heat exchange pipe 26.

[0028] A method for recovering waste heat from the flue gas of a gas boiler includes the following steps: Pre-filtering of flue gas: The high-temperature flue gas of the gas boiler flows into the outer shell from the smoke inlet pipe. After the dust and impurities in the flue gas are filtered by the filter cartridge, the flue gas flows into the first heat exchange pipe; Waste heat recovery: The water in the first heat exchange chamber exchanges heat with the high-temperature flue gas in the first heat exchange pipe, the temperature of the high-temperature flue gas decreases, and the temperature of the water source in the first heat exchange chamber increases; Primary preheating of the water source: The flue gas in the first heat exchange pipe flows into the second heat exchange pipe and exchanges heat with the water source in the second heat exchange chamber, and the water source in the second heat exchange chamber is preheated; Secondary preheating of the water source: The flue gas in the second heat exchange pipe flows into the third heat exchange pipe and exchanges heat with the water source in the third heat exchange chamber, and the water source in the third heat exchange chamber is preheated. At this time, the temperature of the water source in the first heat exchange chamber is the highest, and the temperature of the water source in the third heat exchange chamber is the lowest; Preheated water circulation: Under the transportation of the transfer pump and the connecting pipe, the preheated water in the third heat exchange chamber flows into the second heat exchange chamber, the preheated water in the second heat exchange chamber flows into the first heat exchange chamber, and the water source in the first heat exchange chamber is discharged from the water outlet pipe; Full heat exchange: The driving motor drives the transmission rod, and the transmission rod transmits power through the transmission gear and the gear ring, and the stirring plate stirs the flow of the water source to accelerate heat exchange.

[0029] Working principle or structural principle. When in use, the flue gas of the gas boiler flows into the smoke inlet pipe 31, and then flows into the outer shell 34 through the smoke inlet pipe 31. The filter cartridge 38 filters the impurity particles in the flue gas. Then the high-temperature flue gas flows into the first heat exchange pipe 24 through the connecting pipe 36. The water in the first heat exchange chamber 15 exchanges heat with the high-temperature flue gas in the first heat exchange pipe 24. Since the temperature of the high-temperature flue gas is the highest at this time, the temperature of the water source in the first heat exchange chamber 15 rises rapidly. After heat exchange, the temperature of the flue gas decreases, but there is still a large amount of waste heat. Then the flue gas in the first heat exchange pipe 24 flows into the second heat exchange pipe 25 and exchanges heat with the water source in the second heat exchange chamber 16. At this time, the temperature of the high-temperature flue gas decreases, and the water source in the second heat exchange chamber 16 is preheated. Then the flue gas in the second heat exchange pipe 25 flows into the third heat exchange pipe 26 and exchanges heat with the water source in the third heat exchange chamber 17. The water source in the third heat exchange chamber 17 is preheated, and the temperature of the flue gas drops to the lowest. Then, under the transportation of the transfer pump 13, the preheated water source in the third heat exchange chamber 17 flows into the second heat exchange chamber 16. Since the water source in the third heat exchange chamber 17 has been preheated, the initial temperature of the water source in the second heat exchange chamber 16 during heat exchange can be increased, so that the water temperature in the second heat exchange chamber 16 rises. Similarly, by using the transfer pump 13 to transport the water source in the second heat exchange chamber 16 to the first heat exchange chamber 15, the initial water temperature of the water source in the first heat exchange chamber 15 during heat exchange can be increased. After heat exchange, the water temperature in the first heat exchange chamber 15 can be higher, thus effectively improving the recovery efficiency of the flue gas waste heat. During the heat exchange process, the driving motor 14 drives the transmission rod 18 to rotate. The transmission rod 18 drives the transmission gear 19. The transmission gear 19 drives the toothed ring 21 through the teeth. The toothed ring 21 drives the turntable 20 to rotate. The turntable 20 drives the stirring plate 22. The stirring plate 22 stirs the water sources in the three heat exchange chambers respectively, so as to make the water source fully contact with the heat exchange pipe to improve the heat exchange effect; When the recovery device has been operating for a period of time, clean the filter cartridge 38: control the solenoid valve 37 on the smoke inlet pipe 31 to close, the solenoid valve 37 on the shunt pipe 32 to open, the solenoid valve 37 on the dust discharge pipe 35 to open, and the solenoid valve 37 on the connecting pipe 36 to close; At this time, the flue gas flows into the mounting cover 33 through the shunt pipe 32, then flows into the outer shell 34 through the air inlet hole 42, and finally is discharged through the dust discharge pipe 35. During this process, the flue gas drives the pushing blade 41 to rotate. The pushing blade 41 drives the rotating shaft 39 to rotate. The rotating shaft 39 drives the scraping plate 40. The scraping plate 40 cleans the impurity particles filtered on the inner wall of the filter cartridge 38, and then is discharged through the dust discharge pipe 35 under the drive of the flue gas, realizing the back-blowing and scraping cleaning of the filter cartridge 38; Compared with the prior art, the present invention improves the waste heat recovery efficiency of flue gas without increasing the heat pump by setting three heat exchange tubes and three heat exchange chambers and realizing the circulation of the water source through the delivery pump 13, reducing costs and energy consumption. Moreover, by setting up a water source agitation mechanism, the water source can be made to fully contact the heat exchange tubes, thereby improving the heat exchange effect of the heat exchange tubes.

[0030] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A gas boiler flue gas waste heat recovery device, characterized in that, It includes a waste heat recovery component (101), and the waste heat recovery component (101) includes a recovery tank (11), a connecting pipe (12), a driving motor (14), a transmission rod (18), a transmission gear (19), a turntable (20), a gear ring (21), a stirring plate (22) and a mounting shaft (23); A first heat exchange chamber (15), a second heat exchange chamber (16) and a third heat exchange chamber (17) are formed inside the recovery tank (11). A first heat exchange pipe (24), a second heat exchange pipe (25) and a third heat exchange pipe (26) are respectively installed inside the first heat exchange chamber (15), the second heat exchange chamber (16) and the third heat exchange chamber (17). The two connecting pipes (12) are respectively installed inside the second heat exchange chamber (16) and the third heat exchange chamber (17). A delivery pump (13) is installed on the connecting pipe (12). One end of the transmission rod (18) is fixedly connected to the output shaft of the driving motor (14). The transmission gear (19) is fixedly connected to the outer side wall of the transmission rod (18). The gear ring (21) is fixedly connected to the outer side wall of the turntable (20). The turntable (20) is rotatably connected to the inside of the recovery tank (11) through the mounting shaft (23). The stirring plate (22) is installed on one side of the turntable (20).

2. The gas boiler flue gas waste heat recovery device according to claim 1, wherein The air outlet of the first heat exchange pipe (24) is communicated with the air inlet of the second heat exchange pipe (25), and the air outlet of the second heat exchange pipe (25) is communicated with the air inlet of the third heat exchange pipe (26).

3. A gas boiler flue gas waste heat recovery device according to claim 2, characterized in that, Both ends of one connecting pipe (12) are respectively communicated with the first heat exchange chamber (15) and the second heat exchange chamber (16), and both ends of the other connecting pipe (12) are respectively communicated with the second heat exchange chamber (16) and the third heat exchange chamber (17). The delivery pump (13) is installed on the upper surface of the recovery tank (11).

4. A flue gas waste heat recovery device for a gas boiler according to claim 3, characterized in that Two turntables (20) are symmetrically arranged outside the first heat exchange pipe (24), the second heat exchange pipe (25) and the third heat exchange pipe (26). The transmission rod (18) is rotatably connected to the inside of the recovery tank (11). The driving motor (14) is installed on one side of the recovery tank (11). The outer side wall of the gear ring (21) is meshed with the outer side wall of the transmission gear (19).

5. A gas boiler flue gas waste heat recovery device according to claim 1, characterized in that, A water inlet pipe (27) is installed on the upper surface of the recovery tank (11), and the position of the water inlet pipe (27) corresponds to the position of the third heat exchange chamber (17). A water outlet pipe (28) is installed at the bottom of the front surface of the recovery tank (11), and the position of the water outlet pipe (28) corresponds to the position of the first heat exchange chamber (15).

6. A gas boiler flue gas waste heat recovery device according to claim 1, characterized in that, A filtering component (301) is arranged outside the recovery tank (11). The filtering component (301) includes a smoke inlet pipe (31), a shunt pipe (32), a mounting cover (33), a housing (34), a dust discharge pipe (35), a connecting pipe (36), a filter cartridge (38), a rotating shaft (39), two scraping plates (40) and a pushing blade (41); One end of the smoke inlet pipe (31) communicates with the top end of the outer shell (34). One end of the shunt pipe (32) communicates with the smoke inlet pipe (31). The other end of the shunt pipe (32) communicates with the mounting cover (33). The mounting cover (33) is fixedly connected to the lower surface of the outer shell (34). The connecting pipe (36) is installed on the outer side wall of the outer shell (34) and communicates with the outer shell (34). The filter cartridge (38) is installed inside the outer shell (34). The dust exhaust pipe (35) is installed at the top end of the outer shell (34). The two scraping plates (40) are symmetrically and fixedly connected to the outer side wall of the rotating shaft (39). The rotating shaft (39) is rotatably connected inside the outer shell (34). The pushing blade (41) is fixedly connected to the bottom of the outer side wall of the rotating shaft (39). Solenoid valves (37) are installed on the smoke inlet pipe (31), the shunt pipe (32), the dust exhaust pipe (35) and the connecting pipe (36).

7. The waste heat recovery device for the flue gas of a gas boiler according to claim 6, characterized in that, An air inlet hole (42) is provided on the lower surface of the outer shell (34). The mounting cover (33) communicates with the outer shell (34) through the air inlet hole (42).

8. The waste heat recovery device for the flue gas of a gas boiler according to claim 7, characterized in that, The scraping plate (40) is located inside the filter cartridge (38). The scraping plate (40) is attached to the inner side wall of the filter cartridge (38). The pushing blade (41) is located inside the mounting cover (33).

9. The gas boiler flue gas waste heat recovery device according to claim 8, characterized in that, One end of the connecting pipe (36) away from the outer shell (34) communicates with the air inlet of the first heat exchange pipe (24). A smoke exhaust pipe (29) is installed at the air outlet of the third heat exchange pipe (26).

10. A method for recovering waste heat from the flue gas of a gas boiler, which is applied to the waste heat recovery device for the flue gas of a gas boiler as described in any one of claims 1-9, characterized in that, Including the following steps: Pre-filtering of flue gas: The high-temperature flue gas of the gas boiler flows into the outer shell from the smoke inlet pipe. After the dust and impurities in the flue gas are filtered by the filter cartridge, the flue gas flows into the first heat exchange pipe; Waste heat recovery: The water in the first heat exchange chamber exchanges heat with the high-temperature flue gas in the first heat exchange pipe. The temperature of the high-temperature flue gas decreases, and the temperature of the water source in the first heat exchange chamber increases; Primary preheating of the water source: The flue gas in the first heat exchange pipe flows into the second heat exchange pipe and exchanges heat with the water source in the second heat exchange chamber. The water source in the second heat exchange chamber is preheated; Secondary preheating of the water source: The flue gas in the second heat exchange pipe flows into the third heat exchange pipe and exchanges heat with the water source in the third heat exchange chamber. The water source in the third heat exchange chamber is preheated. At this time, the temperature of the water source in the first heat exchange chamber is the highest, and the temperature of the water source in the third heat exchange chamber is the lowest; Preheated water circulation: Under the transportation of the delivery pump and the connecting pipe, the preheated water in the third heat exchange chamber flows into the second heat exchange chamber. The preheated water in the second heat exchange chamber flows into the first heat exchange chamber. The water source in the first heat exchange chamber is discharged from the water outlet pipe; Full heat exchange: The driving motor drives the transmission rod. The transmission rod transmits power through the transmission gear and the gear ring. The stirring plate stirs the flow of the water source to accelerate heat exchange.

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