Waste heat recovery device capable of improving recovery efficiency of waste heat boiler

Abstract

A waste heat recovery device capable of improving the recovery efficiency of a waste heat boiler belongs to the technical field of industrial waste heat recovery equipment and is used for improving the heat recovery efficiency of the waste heat boiler. According to the technical scheme, a heat exchange water inlet pipe is installed in the center of the upper end face of a tank body, a heat exchange water outlet pipe is installed on the bottom face of the tank body, electromagnetic valves are installed on the heat exchange water inlet pipe and the heat exchange water outlet pipe respectively, and a flue gas inlet pipe and a flue gas outlet pipe are installed on the two opposite sides of the top face of the tank body respectively. The flue gas inlet pipe and the flue gas outlet pipe are respectively provided with an electromagnetic valve, the heat exchange pipe is placed in an inner cavity of the tank body, the gas inlet ends and the gas outlet ends of the flue gas inlet pipe and the flue gas outlet pipe are connected with the two ends of the heat exchange pipe, and the flue gas filter is installed outside the tank body. The heat exchange time of the high-temperature flue gas and the heat exchange water can be effectively controlled, so that the heat exchange water can fully absorb heat in the high-temperature flue gas, the heat energy utilization rate of the high-temperature flue gas is improved, and the purpose of effectively improving the waste heat recovery efficiency is achieved.

Description

Technical Field

[0001] This utility model relates to a time-limited recovery device for waste heat boilers that can improve the heat recovery efficiency of waste heat boilers, belonging to the technical field of industrial waste heat recovery equipment. Background Technology

[0002] Traditional waste heat boilers primarily utilize economizers for waste heat recovery. An economizer is an integral part of the boiler, installed within the boiler flue. It comprises numerous reciprocating heat exchange pipes, through which hot water circulates. Outside these pipes, high-temperature flue gas flows. As the flue gas passes through the pipes, heat exchange occurs, raising the temperature of the hot water and lowering the flue gas temperature. This reheated hot water then re-enters the boiler, increasing the boiler's feedwater temperature and thus achieving coal savings.

[0003] Traditional waste heat recovery systems are primarily designed and applied in industrial sectors that generate large amounts of waste heat, such as chemical, metallurgical, textile, and paper industries. For industrial enterprises or equipment with smaller waste heat generation, the economic benefits may be insignificant, or even nonexistent due to high equipment and maintenance costs, thus limiting their utilization of waste heat recovery. Furthermore, although waste heat recovery devices can recover some waste heat, their efficiency remains limited. A major reason for this is the short heat exchange time between high-temperature flue gas and heat exchange pipes in existing devices. A significant portion of the high-temperature flue gas is discharged before sufficient heat exchange, resulting in substantial energy waste, reduced efficiency, and potential environmental pollution. Therefore, to effectively improve waste heat recovery efficiency, measures must be taken to extend the heat exchange time between the high-temperature flue gas and the heat exchange water. This allows the heat exchange water to fully absorb the heat from the high-temperature flue gas before discharge, thereby increasing the thermal energy utilization rate of the flue gas and effectively improving waste heat recovery efficiency. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a waste heat recovery device that can improve the efficiency of waste heat boiler recovery. This waste heat recovery device can control the heat exchange time between high-temperature flue gas and hot water, so that the hot water can fully absorb the heat in the high-temperature flue gas and then discharge the high-temperature flue gas, thereby improving the thermal energy utilization rate of the high-temperature flue gas and achieving the purpose of effectively improving the waste heat recovery efficiency.

[0005] The technical solution to the above technical problem is:

[0006] A waste heat recovery device capable of improving the efficiency of waste heat boiler recovery includes a tank, support legs, a hot water inlet pipe, an inlet pipe solenoid valve, a hot water outlet pipe, an outlet pipe solenoid valve, a flue gas inlet pipe, an inlet pipe solenoid valve, a flue gas outlet pipe, an outlet pipe solenoid valve, heat exchange tubes, a flue gas temperature sensor, a hot water temperature sensor, and a flue gas filter. The tank is an upright cylindrical body. Support legs are installed at the lower end of the tank, with three support legs evenly distributed around the circumference of the tank. A hot water inlet pipe is installed at the center of the upper surface of the tank, and an inlet pipe solenoid valve is installed on the hot water inlet pipe. A hot water outlet pipe is installed on the bottom surface of the tank, and a heat exchange tube is installed on the hot water outlet pipe. The tank has an outlet solenoid valve, and flue gas inlet and outlet pipes are installed on opposite sides of the top surface of the tank. Inlet and outlet solenoid valves are installed on the flue gas inlet and outlet pipes, respectively. The heat exchange tube is placed in the inner cavity of the tank and is a spiral tube that rotates from top to bottom. The inlet and outlet ends of the flue gas inlet and outlet pipes extend into the tank and are connected to the two ends of the heat exchange tube. A flue gas temperature sensor is installed on the flue gas outlet pipe. A water exchange temperature sensor is installed on the inner side wall of the tank. The flue gas filter is placed outside the tank, and the flue gas outlet pipe of the tank is connected to the filter inlet pipe of the flue gas filter.

[0007] The aforementioned waste heat recovery device, which can improve the efficiency of waste heat boiler recovery, has its inlet water pipe solenoid valve, outlet water pipe solenoid valve, inlet air pipe solenoid valve, and outlet air pipe solenoid valve connected at both ends to the hot water exchange inlet pipe, hot water exchange outlet pipe, flue gas inlet pipe, and flue gas outlet pipe, respectively, via flanges.

[0008] The aforementioned waste heat recovery device, which can improve the efficiency of waste heat boiler recovery, comprises a flue gas filter consisting of a filter tank, a filter inlet pipe, a filter outlet pipe, a drain pipe, a manual valve, and a pressure gauge. The filter tank is cylindrical, and several sets of filter screens are installed inside the filter tank. A filter inlet pipe and a filter outlet pipe are installed on opposite sides of the filter tank, respectively. The filter inlet pipe is connected to the flue gas outlet pipe of the tank body, and the outlet of the filter outlet pipe is open. A drain pipe is installed on the bottom surface of the lower end of the filter tank, and a manual valve is installed at the drain outlet of the drain pipe. A pressure gauge is installed on the top of the filter tank.

[0009] The aforementioned waste heat recovery device, which improves the efficiency of waste heat boiler recovery, also includes a sludge scraping mechanism. This mechanism consists of a scraper seat, scrapers, a crossbar, a water wheel mounting column, and a water wheel. The scraper seat is a circular ring, and the scrapers are long plates. Multiple scrapers are evenly distributed around the circular ring of the scraper seat. The rear ends of the scrapers are vertically welded to the outer periphery of the circular ring of the scraper seat. The lower edges of the scraper plates slide vertically against the bottom surface of the tank. The inlet of the hot water outlet pipe, installed on the bottom surface of the tank, is located inside the tank. A bearing is fitted onto the inlet of the hot water outlet pipe. The lower edge of the inner hole of the scraper seat has an annular groove, which is fitted onto the bearing at the inlet of the hot water outlet pipe. The crossbar is fixed in the inner hole of the scraper seat. A water wheel mounting column is vertically welded to the lower surface of the center of the crossbar. A water wheel is fixedly connected to the lower end of the water wheel mounting column. The water wheel mounting column and the water wheel are located inside the inlet of the hot water outlet pipe.

[0010] The beneficial effects of this utility model are:

[0011] The tank body of this invention is connected to a hot water inlet pipe and a hot water outlet pipe at its upper and lower ends, respectively. The hot water enters the tank body through the hot water inlet pipe and exits through the hot water outlet pipe after heat exchange. A heat exchange tube is placed in the hot water inside the tank body, and its two ends are connected to a flue gas inlet pipe and a flue gas outlet pipe, respectively. High-temperature flue gas exchanges heat with the hot water inside the tank body through the heat exchange tube. A solenoid valve for the inlet pipe, a solenoid valve for the outlet pipe, a solenoid valve for the inlet pipe, and a solenoid valve for the outlet pipe are respectively installed in the hot water inlet pipe, the hot water outlet pipe, the flue gas inlet pipe, and the flue gas outlet pipe, controlling the hot water exchange and the high-temperature flue gas respectively. The residence time of flue gas in the tank and heat exchange tubes allows for sufficient heat exchange between the hot water and the high-temperature flue gas. Flue gas temperature sensors and hot water temperature sensors can monitor the temperature of the flue gas and the hot water respectively, providing a basis for the residence time of the flue gas and the hot water. The flue gas filter can filter and purify the flue gas discharged after heat exchange, preventing the discharged flue gas from polluting the environment. The water wheel of the sludge scraping mechanism can drive the scraper seat and scraper to rotate under the push of the discharged water from the hot water outlet pipe. The scraper can scrape off the dirt on the bottom of the tank, preventing dirt from accumulating on the bottom of the tank.

[0012] This invention has a simple structure and is easy to use. It can effectively control the heat exchange time between high-temperature flue gas and hot water, so that the hot water can fully absorb the heat in the high-temperature flue gas before the high-temperature flue gas is discharged. This improves the thermal energy utilization rate of the high-temperature flue gas, effectively improves the waste heat recovery efficiency, and avoids the pollution of the environment by the discharged flue gas. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model;

[0014] Figure 2 yes Figure 1A cross-sectional schematic diagram of the tank body;

[0015] Figure 3 This is a schematic diagram of the heat exchange tube structure;

[0016] Figure 4 This is a schematic diagram of the structure of a flue gas filter;

[0017] Figure 5 This is a schematic diagram showing the positions of the heat exchange tubes and the sludge scraping mechanism;

[0018] Figure 6 This is a schematic diagram showing the connection between the sludge scraping mechanism and the hot water outlet pipe;

[0019] Figure 7 This is an exploded view of the sludge scraping mechanism;

[0020] Figure 8 yes Figure 7 A bottom view.

[0021] The following are marked in the diagram: Tank body 1, Support leg 2, Hot water inlet pipe 3, Inlet pipe solenoid valve 4, Hot water outlet pipe 5, Outlet pipe solenoid valve 6, Flue gas inlet pipe 7, Inlet pipe solenoid valve 8, Flue gas outlet pipe 9, Outlet pipe solenoid valve 10, Flue gas temperature sensor 11, Heat exchange pipe 12, Hot water temperature sensor 13, Flange 14, Flue gas filter 15, Filter tank 16, Filter inlet pipe 17, Filter outlet pipe 18, Sewage pipe 19, Manual valve 20, Pressure gauge 21, Sludge scraping mechanism 22, Scraper seat 23, Scraper 24, Annular groove 25, Bearing 26, Cross rod 27, Water wheel mounting column 28, Water wheel 29. Detailed Implementation

[0022] This utility model consists of a tank body 1, supporting feet 2, hot water inlet pipe 3, inlet pipe solenoid valve 4, hot water outlet pipe 5, outlet pipe solenoid valve 6, flue gas inlet pipe 7, inlet pipe solenoid valve 8, flue gas outlet pipe 9, outlet pipe solenoid valve 10, flue gas temperature sensor 11, heat exchange pipe 12, hot water temperature sensor 13, flue gas filter 15, and sludge scraping mechanism 22.

[0023] Figure 1 , 2 As shown, the tank 1 is an upright cylindrical body, and support legs 2 are installed at the lower end of the tank 1. The three support legs 2 are evenly distributed around the circumference of the tank 1.

[0024] Figure 1 , 2 The display shows that a hot water inlet pipe 3 is installed at the center of the upper end face of tank 1, and a hot water outlet pipe 5 is installed on the bottom face of tank 1. Low-temperature hot water enters tank 1 through the hot water inlet pipe 3, its temperature is increased after heat exchange, and then high-temperature water is discharged from the hot water outlet pipe 5.

[0025] Figure 1 , 2 The display shows that an inlet solenoid valve 4 is installed on the hot water inlet pipe 3, and an outlet solenoid valve 6 is installed on the hot water outlet pipe 5. The two ends of the inlet solenoid valve 4 and the outlet solenoid valve 6 are connected to the hot water inlet pipe 3 and the hot water outlet pipe 5 respectively via flanges 14. The inlet solenoid valve 4 and the outlet solenoid valve 5 can adjust the flow rate and residence time of the hot water entering the tank 1 to control the temperature of the hot water. A hot water temperature sensor 13 is installed on the inner wall of the tank 1. The hot water temperature sensor 13 can monitor the temperature of the hot water inside the tank 1 and provide a basis for the residence time of the hot water in the tank 1, ensuring sufficient heat exchange between the hot water and the high-temperature flue gas.

[0026] Figure 1 , 2 As shown in Figure 3, a flue gas inlet pipe 7 and a flue gas outlet pipe 9 are respectively installed on opposite sides of the top surface of the tank 1. A heat exchange pipe 12 is placed inside the tank 1. The heat exchange pipe 12 is a spiral tube that rotates from top to bottom. The inlet and outlet ends of the flue gas inlet pipe 7 and the flue gas outlet pipe 9 extend into the tank 1 and connect to both ends of the heat exchange pipe 12. High-temperature flue gas enters the heat exchange pipe 12 through the flue gas inlet pipe 7. After heat exchange with the low-temperature water inside the tank 1, the temperature of the heat exchange pipe 12 is reduced, and then the low-temperature flue gas is discharged from the flue gas outlet pipe 9.

[0027] Figure 1 , 2 The display shows that an inlet solenoid valve 8 and an outlet solenoid valve 10 are respectively installed on the flue gas inlet pipe 7 and the flue gas outlet pipe 9. The two ends of the inlet solenoid valve 8 and the outlet solenoid valve 10 are connected to the flue gas inlet pipe 7 and the flue gas outlet pipe 9 via flanges 14. The inlet solenoid valve 8 and the outlet solenoid valve 10 can adjust the flow rate and residence time of the heat exchange flue gas entering the heat exchange tube 12 to control the temperature of the heat exchange flue gas. A flue gas temperature sensor 11 is installed on the flue gas outlet pipe 9. The flue gas temperature sensor 11 can monitor the temperature of the heat exchange flue gas in the heat exchange tube 12, providing a basis for the residence time of the heat exchange flue gas in the heat exchange tube 12, ensuring that the heat exchange flue gas and the heat exchange water can fully exchange heat.

[0028] Figure 1 , 2 As shown, the flue gas filter 15 is placed outside the tank body 1, and the flue gas outlet pipe 9 of the tank body 1 is connected to the filter inlet pipe 17 of the flue gas filter 15. After heat exchange, the flue gas is discharged from the flue gas outlet pipe 9 of the tank body 1 and then enters the flue gas filter 15 for filtration before being discharged.

[0029] Figure 4The display shows that the flue gas filter 15 consists of a filter canister 16, a filter inlet pipe 17, a filter outlet pipe 18, a drain pipe 19, a manual valve 20, and a pressure gauge 21. The filter canister 16 is cylindrical, and its interior contains several sets of filter screens to filter the flue gas. The filter inlet pipe 17 and filter outlet pipe 18 are installed on opposite sides of the filter canister 16, respectively. The filter inlet pipe 17 is connected to the flue gas outlet pipe 9 of the canister 1, and the outlet of the filter outlet pipe 18 is open. A drain pipe 19 is installed on the bottom surface of the filter canister 16, and a manual valve 20 is installed at the drain outlet of the drain pipe 19. After dust accumulates in the filter canister 16, the manual valve 20 can be opened to remove the dust. A pressure gauge is installed on the top of the filter canister 16 to monitor the air pressure inside.

[0030] Figure 5 , 6 The display shows that there is a sludge scraping mechanism 22 below the heat exchange tube 12, which is rotatably connected to the inlet of the hot water outlet pipe 5 installed on the bottom surface of the tank 1.

[0031] Figure 7 , 8 The scraping mechanism 22 consists of a scraper seat 23, a scraper 24, a cross rod 27, a water wheel mounting column 28, and a water wheel 29. The scraper seat 23 is a ring, and the lower edge of the inner hole of the scraper seat 23 has an annular groove 25. A bearing 26 is fitted on the inlet of the hot water outlet pipe 5. The annular groove 25 of the scraper seat 23 is fitted on the bearing 26 at the inlet of the hot water outlet pipe 5, so the scraper seat 23 can rotate around the inlet of the hot water outlet pipe 5.

[0032] Figure 7 , 8 The scraper 24 is a long plate, with multiple scrapers 24 evenly distributed around the ring of the scraper seat 23. The rear ends of the scrapers 24 are vertically welded to the outer periphery of the ring of the scraper seat 23, and the lower edges of the scraper 24 slide vertically against the bottom surface of the tank 1. A cross rod 27 is fixed in the inner hole of the scraper seat 23. A water wheel mounting column 28 is vertically welded to the lower surface of the center of the cross rod 27. A water wheel 29 is fixedly connected to the lower end of the water wheel mounting column 28. The water wheel mounting column 28 and the water wheel 29 are located inside the inlet of the hot water outlet pipe 5. The water wheel 29 of the sludge scraping mechanism 22 can drive the scraper seat 23 and the scrapers 24 to rotate under the push of the discharged water from the hot water outlet pipe 5. The scrapers 24 can scrape off the dirt on the bottom surface of the tank 1, preventing dirt from accumulating on the bottom of the tank 1.

[0033] The usage process of this utility model is as follows:

[0034] Low-temperature hot water enters the inner cavity of tank 1 through hot water inlet pipe 3 and inlet pipe solenoid valve 4. At the same time, high-temperature flue gas from the boiler enters the heat exchange tube 12 inside tank 1 through flue gas inlet pipe 7 and inlet pipe solenoid valve 8. This allows the high-temperature flue gas in heat exchange tube 12 to exchange heat with the low-temperature hot water in the inner cavity of tank 1, thereby heating the hot water. Simultaneously, the boiler can recover heat from the high-temperature flue gas generated during operation.

[0035] The hot water temperature sensor 13 can automatically detect the temperature of the hot water in the tank 1 and monitor whether the heat exchange rate meets the standard after heat exchange. Based on the temperature of the hot water provided by the hot water temperature sensor 13, the operator can control the opening and closing of the inlet solenoid valve 8 and the outlet solenoid valve 10, which can keep the high temperature flue gas inside the heat exchange tube 12 and heat the heat exchange tube 12, thereby improving the conversion rate of the device for heat exchange.

[0036] After the hot water in tank 1 reaches the heat exchange temperature, the hot water is drained, and then low-temperature hot water is injected into tank 1 to continue the heat exchange.

[0037] When hot water is discharged, the flow of water drives the water wheel 29 of the sludge scraping mechanism 22 to rotate. The water wheel 29 can drive the scraper seat 23 and scraper 24 to rotate. The scraper 24 can scrape off the dirt on the bottom surface of the tank 1 to prevent dirt from accumulating on the bottom surface of the tank 1.

[0038] The flue gas inlet temperature of the air preheater in an industrial furnace waste heat recovery system varies depending on the process heating furnace used, generally ranging from 200℃ to 400℃. This temperature range is based on the actual conditions of various industrial heating furnaces, and the specific value will vary depending on the specific type of heating furnace, fuel type, and operating conditions. The flue gas outlet temperature is generally between 70℃ and 140℃. The outlet temperature is designed to ensure that most of the waste heat in the flue gas is effectively recovered, while avoiding excessively low temperatures that could cause water vapor in the flue gas to condense, producing acidic condensate that corrodes the equipment. There is no fixed standard value for the inlet water temperature of the boiler preheater, as it is affected by various factors such as boiler type, operating conditions, and system design. However, generally speaking, the inlet water temperature of the boiler preheater is relatively low in order to absorb the waste heat in the flue gas. In some cases, such as when using the boiler preheater to heat a cleaning tank at a constant temperature, the inlet water temperature may be adjusted according to the specific needs of the cleaning tank. The outlet water temperature depends on the design efficiency of the preheater, the inlet water temperature, and the temperature difference between the flue gas inlet and outlet. Generally, the outlet water temperature of a boiler preheater is higher than the inlet water temperature. The specific value depends on the various factors mentioned above. In most cases, the temperature difference between the inlet and outlet water of the boiler preheater should be above 15℃ to ensure the preheating effect. However, the specific water temperature value needs to be determined based on the boiler model, capacity, and operating conditions.

[0039] A specific embodiment of this utility model is as follows:

[0040] The diameter of tank 1 is 600mm and the height is 1000mm, and the height of support leg 2 is 100mm;

[0041] The diameter of the hot water inlet pipe 3 is 100mm and the length is 800mm;

[0042] The diameter of the hot water outlet pipe 5 is 100mm and the length is 800mm;

[0043] The inlet solenoid valve 4 and the outlet solenoid valve 6 are both model Festo MS6-LR-1.

[0044] The diameter of the flue gas inlet pipe 7 is 200mm and the length is 1200mm;

[0045] The diameter of the flue gas outlet pipe 9 is 200mm and the length is 1200mm;

[0046] The model of the intake pipe solenoid valve 8 and the exhaust pipe solenoid valve 10 is BZCM-200F;

[0047] The flue gas temperature sensor 11 and the hot water temperature sensor 13 are both model SGM447.

[0048] The heat exchange tube 12 has a diameter of 600 mm and a height of 1200 mm, and the spiral tube has a diameter of 32 mm.

[0049] The filter tank 16 has a diameter of 300 mm and a height of 600 mm;

[0050] The outer diameter of the scraper seat 23 is 124 mm, the inner diameter is 114 mm, and the thickness is 10 mm.

[0051] The scraper 24 is 200mm long, 30mm wide, and 6mm thick.

Claims

1. A waste heat recovery device capable of improving the efficiency of waste heat boiler recovery, characterized in that: It includes a tank body (1), support legs (2), hot water inlet pipe (3), inlet pipe solenoid valve (4), hot water outlet pipe (5), outlet pipe solenoid valve (6), flue gas inlet pipe (7), inlet pipe solenoid valve (8), flue gas outlet pipe (9), outlet pipe solenoid valve (10), heat exchange pipe (12), flue gas temperature sensor (11), hot water temperature sensor (13), and flue gas filter (15). The tank body (1) is an upright cylindrical body. Support legs (2) are installed at the lower end of the tank body (1). The three support legs (2) are evenly distributed around the circumference of the tank body (1). The hot water inlet pipe (3) is installed on the upper end of the tank body (1). The inlet pipe solenoid valve (4) is installed on the hot water inlet pipe (3). The hot water outlet pipe (5) is installed on the bottom surface of the tank body (1). The outlet pipe solenoid valve (6) is installed on the hot water outlet pipe (5). (1) A flue gas inlet pipe (7) and a flue gas outlet pipe (9) are installed on opposite sides of the top surface. An inlet pipe solenoid valve (8) and an outlet pipe solenoid valve (10) are installed on the flue gas inlet pipe (7) and the flue gas outlet pipe (9) respectively. A heat exchange pipe (12) is placed in the inner cavity of the tank (1). The heat exchange pipe (12) is a spiral pipe that spirals from top to bottom. The inlet end and outlet end of the flue gas inlet pipe (7) and the flue gas outlet pipe (9) extend into the tank (1) and are connected to the two ends of the heat exchange pipe (12). A flue gas temperature sensor (11) is installed on the flue gas outlet pipe (9). A water exchange temperature sensor (13) is installed on the inner wall of the tank (1). A flue gas filter (15) is placed outside the tank (1). The flue gas outlet pipe (9) of the tank (1) is connected to the filter inlet pipe (17) of the flue gas filter (15). It also has a sludge scraping mechanism (22), which consists of a scraper seat (23), a scraper (24), a cross rod (27), a water wheel mounting column (28), and a water wheel (29). The scraper seat (23) is a ring, and the scraper (24) is a long plate. Multiple scrapers (24) are evenly distributed around the ring of the scraper seat (23). The rear ends of the multiple scrapers (24) are vertically welded to the outer periphery of the ring of the scraper seat (23). The lower edge of the plate surface of the multiple scrapers (24) slides vertically with the bottom surface of the tank. The inlet of the hot water outlet pipe (5) installed on the bottom surface of the tank is located inside the tank (1). A bearing (26) is fitted on the inlet of the hot water outlet pipe (5). The lower edge of the inner hole of the scraper seat (23) has an annular groove (25). The annular groove (25) of the scraper seat (23) is fitted on the bearing (26) of the inlet of the hot water outlet pipe (5). The cross rod (27) is fixed in the inner hole of the scraper seat (23). The lower surface of the center of the cross rod (27) is vertically welded with a water wheel mounting column (28). The lower end of the water wheel mounting column (28) is fixedly connected to a water wheel (29). The water wheel mounting column (28) and the water wheel (29) are located inside the inlet of the hot water outlet pipe (5).

2. The waste heat recovery device according to claim 1, which can improve the waste heat boiler recovery efficiency, is characterized in that: The two ends of the inlet pipe solenoid valve (4), outlet pipe solenoid valve (6), air inlet pipe solenoid valve (8), and air outlet pipe solenoid valve (10) are respectively connected to the hot water inlet pipe (3), hot water outlet pipe (5), flue gas inlet pipe (7), and flue gas outlet pipe (9) through flanges (14).

3. The waste heat recovery device according to claim 1, which can improve the waste heat boiler recovery efficiency, is characterized in that: The flue gas filter (15) consists of a filter tank (16), a filter inlet pipe (17), a filter outlet pipe (18), a drain pipe (19), a manual valve (20), and a pressure gauge (21). The filter tank (16) is a cylindrical body. Several sets of filter screens are installed inside the filter tank (16). The filter inlet pipe (17) and the filter outlet pipe (18) are installed on opposite sides of the filter tank (16). The filter inlet pipe (17) is connected to the flue gas outlet pipe (9) of the tank body (1). The outlet of the filter outlet pipe (18) is open. The drain pipe (19) is installed on the bottom surface of the lower end of the filter tank (16). The drain outlet of the drain pipe (19) is equipped with a manual valve (20). The pressure gauge (21) is installed on the top of the filter tank (16).

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