Flue gas waste heat utilization system of aluminum oxide roasting furnace

Abstract

The invention relates to the technical field of roasting furnace flue gas waste heat recovery and provides an aluminum oxide roasting furnace flue gas waste heat utilization system which comprises a total heat exchanger, a plate heat exchanger and a circulating water supply system, the total heat exchanger comprises a heat exchange tank, a spraying assembly and a settling chamber, the spraying assembly and the settling chamber are arranged in the heat exchange tank, and the inner side wall of the heat exchange tank is coated with glass flakes; the bottom of the heat exchange tank communicates with a smoke inlet channel, and the top of the heat exchange tank communicates with a smoke exhaust channel. The plate heat exchanger comprises a heat exchanger body, a heat recovery calandria and a heat recovery inlet pipe which are communicated with one side of the heat exchanger body, and a heat utilization calandria and a heat utilization inlet pipe which are communicated with the other side of the heat exchanger body; and the circulating water supply system is communicated between the plate heat exchanger and the heat exchange tank body and is used for driving circulating water in the heat exchange tank body to flow to the spray header after passing through the plate heat exchanger. The overall recovery utilization rate of the flue gas waste heat is greatly increased.

Description

Technical Field

[0001] The present application relates to the technical field of recovery of waste heat from smoke from a roasting furnace, and in particular to a system for utilizing waste heat from smoke from an alumina roasting furnace. Background Art

[0002] Alumina roasting is the last step in alumina production. Roasting refers to the process of removing the attached water and crystal water of aluminum hydroxide under high temperature conditions and completing the partial γ-Al 2 O 3 To α-Al 2 O 3 The process of converting aluminum oxide into aluminum oxide suitable for electrolytic aluminum. Alumina roasting is a strong endothermic reaction, and the energy consumption accounts for 13% to 16% of the total energy consumption of the entire alumina production. The main heat expenditure of the roasting furnace is as follows: the proportion of sensible heat taken away by the product alumina is about 10.53%, the proportion of heat taken away by wet flue gas is about 59.79%, of which the proportion of heat taken away by dry flue gas is 10.76%, and the proportion of heat taken away by water vapor in the flue gas is as high as 47.03%. The temperature of the exhausted wet flue gas is about 150~180℃, the water content of the flue gas is about 40%, and the waste heat of the flue gas has great utilization value.

[0003] At present, most of the waste heat utilization of flue gas from alumina roasting furnaces only utilizes the sensible heat of flue gas, which is used to heat the seed liquor, provide heating or domestic water. The total amount of latent heat in flue gas is about 4.5 times the sensible heat (calculation conditions: flue gas temperature 150℃, moisture content 40%), which is much larger than the sensible heat. Considering that the water vapor in the flue gas needs to be reduced to below the dew point when condensing, but H is easily precipitated in the low temperature section. 2 SO 4 , HCl and other acidic condensates, causing corrosion and perforation of the heat exchanger.

[0004] In summary, there is an urgent need for a flue gas waste heat recovery system that is efficient, reliable and economical. Summary of the invention

[0005] In order to solve the above problems, the present application provides an alumina roasting furnace flue gas waste heat utilization system.

[0006] The present application provides a system for utilizing waste heat from flue gas of an alumina roasting furnace, which adopts the following technical solution: A system for utilizing waste heat from flue gas of an alumina roasting furnace, comprising: A total heat exchanger, comprising a heat exchange tank body, a spray assembly and a sedimentation chamber arranged in the heat exchange tank body, wherein the inner wall of the heat exchange tank body is coated with glass flakes; the spray assembly comprises a spray head and a water spray plate arranged below the spray head, wherein a plurality of water spray holes are provided on the water spray plate, and a plurality of water spray plates are arranged at intervals in the vertical direction, wherein the bottom of the heat exchange tank body is connected to a smoke inlet channel, and the top of the heat exchange tank body is connected to a smoke exhaust channel; The plate heat exchanger comprises a heat exchanger body, a heat recovery pipe and a heat recovery inlet pipe connected to one side of the heat exchanger body, and a heat utilization pipe and a heat utilization inlet pipe connected to the other side of the heat exchanger body; The circulating water supply system is connected between the plate heat exchanger and the heat exchange tank body, and is used to drive the circulating water in the heat exchange tank body to flow through the plate heat exchanger and then flow to the spray head.

[0007] By adopting the above technical solutions, the full heat heat exchanger can effectively absorb the sensible heat and latent heat in the flue gas, significantly improving the waste heat recovery efficiency. Coating the inner wall of the heat exchange tank with glass flakes can prevent dew point corrosion and extend the service life of the equipment. Among them, the high-efficiency nozzles in the full heat heat exchanger can evenly spray water into fine droplets, significantly increase the contact area with the flue gas, and improve the efficiency of the initial heat and mass transfer; the design of the water spray plate further promotes the deep interaction between the circulating water and the flue gas, and enhances the secondary heat and mass transfer effect. The high-temperature circulating water obtained after absorbing the heat of the flue gas exchanges the heat to the outside through the plate heat exchanger for reasonable utilization, reducing the overall energy consumption. Greatly reduce the heat loss of flue gas emissions, while avoiding the waste of water resources, and improve the environmental protection and economy of the alumina roasting process.

[0008] Optionally, the circulating water supply system includes a water outlet pipe, a water return pipe and a circulating pump, wherein one end of the water outlet pipe is connected to the bottom of the heat exchange tank body, and the other end is connected to the heat recovery inlet pipe; one end of the water return pipe is connected to the heat recovery drain pipe, and the other end is connected to the sprinkler head; the circulating pump is connected to the pipe section of the water outlet pipe, and is used to drive the circulating water in the water outlet pipe to move toward the heat recovery inlet pipe.

[0009] By adopting the above technical solution, the outlet pipe guides the high-temperature circulating water at the bottom of the heat exchange tank to the heat recovery inlet pipe of the plate heat exchanger. The circulating water after heat exchange in the plate heat exchanger returns to the sprinkler head through the return pipe and finally flows back into the heat exchange tank. This process not only ensures the effective transfer and utilization of flue gas waste heat, but also improves the energy efficiency of the system. The role of the circulation pump further ensures the circulation fluidity of the circulating water, ensures the stability and continuity of the heat exchange, and thus significantly improves the heat recovery effect of the entire system.

[0010] Optionally, it also includes a water replenishment component, which includes a water replenishment pipe and a water replenishment pump, one end of the water replenishment pipe is connected to the water outlet pipe; the water replenishment pump is connected to the pipe section of the water replenishment pipe, and is used to drive the circulating water in the water replenishment pipe to move toward the water outlet pipe.

[0011] By adopting the above technical solution, the stable operation of the circulating water supply system can be ensured. The addition of the water replenishment component enables the system to replenish water in time when the circulating water is consumed or lost, maintain the water balance of the system, and thus ensure that the spraying operation in the total heat exchanger is continuously and effectively carried out. Among them, the coordinated use of the water replenishment pipe and the water replenishment pump realizes the automatic water replenishment function, simplifies the operation process and reduces the labor maintenance cost.

[0012] Optionally, it also includes a water recoverer, which is connected to a recovery liquid pipe, and the recovery liquid pipe is connected to the sedimentation chamber; a recovery pump is arranged on the recovery liquid pipe, and the recovery pump is used to drive the circulating water in the sedimentation chamber to flow into the water recoverer.

[0013] By adopting the above technical solution, the water contained in the flue gas is condensed through the total heat exchanger. As time goes by, the amount of flue gas condensation gradually increases, but the heat power of the waste water recovered by the total heat exchanger is rated. Therefore, there will be excess condensed water, which enters the sedimentation chamber. The condensed water in the sedimentation chamber is transported to the water recovery device through a recovery pump, which realizes the effective recovery of water in the flue gas and avoids the waste of water resources. The recovered condensed water contains acidic components. After further treatment by the water recovery device, it can ensure that the water quality meets the standard, thereby reducing environmental pollution and improving the utilization rate of water resources.

[0014] Optionally, the smoke inlet channel is connected to a smoke exhaust branch pipe, the smoke exhaust branch pipe is connected to the smoke exhaust channel, and a first opening and closing valve is provided on the smoke exhaust branch pipe.

[0015] By adopting the above technical solution, flexible smoke diversion control can be achieved during the smoke treatment process. The smoke exhaust branch pipe and the first on-off valve on it are added, so that the operator can open or close the branch pipe according to the actual working conditions, thereby adjusting the smoke flow and pressure entering the total heat exchanger to ensure the stability and efficiency of the system operation. At the same time, in an emergency, the first on-off valve can be opened to quickly discharge excess smoke, thereby improving the safety performance of the system.

[0016] Optionally, a heat absorbing tube is further provided in the heat exchange tank, and the heat absorbing tube is located below the spray assembly; The heat absorbing cylinder comprises a cylinder body and a heat absorbing channel arranged in the cylinder body. A plurality of heat absorbing channels are arranged at intervals around the axis of the cylinder body, and a plurality of heat absorbing fins are arranged in each of the heat absorbing channels.

[0017] By adopting the above technical solution, the setting of the heat absorption tube can further enhance the recovery efficiency of flue gas waste heat. The multiple heat absorption channels in the heat absorption tube increase the contact area between the flue gas and the heat exchange medium, and cooperate with the heat absorption fins in the heat absorption channel to make the heat transfer more sufficient. This design not only improves the absorption capacity of the sensible heat of the flue gas, but also effectively captures the latent heat of water vapor in the flue gas; when the water moves along the water spray plate and falls toward the bottom of the heat exchange tank, the water will pass through the heat absorption channel and absorb the heat on the heat exchange fins to achieve further heat absorption, thereby significantly improving the overall thermal energy utilization rate of the system.

[0018] Optionally, the heat absorbing cylinder is rotatably disposed in the heat exchange tank body, and a driving component for driving the cylinder body to rotate is disposed in the heat exchange tank body; The heat exchange tank is also provided with a backwashing assembly, which includes a flushing head and a plurality of cleaning nozzles connected to one end of the flushing head. The flushing head is located below one of the heat absorption channels, and the shape of the flushing head is adapted to the shape of the inner circle of the heat absorption channel. The flushing head is connected to a liquid supply pipe, and one end of the liquid supply pipe is located outside the heat exchange tank.

[0019] By adopting the above technical solution, the heat absorption cylinder is rotatably arranged in the heat exchange tank body, and rotates in conjunction with the driving component. On the one hand, it can make the flue gas in the heat absorption channel fully contact with the circulating water, improve the heat transfer efficiency and avoid local dust accumulation. On the other hand, it is convenient for the backwashing component to align each heat absorption channel in turn. The flushing head and cleaning nozzle in the backwashing component can effectively clean each heat absorption channel one by one, preventing blockage caused by dust accumulation after long-term use, thereby extending the service life of the equipment and maintaining stable waste heat recovery performance. The liquid supply pipe realizes the connection between the flushing head and the external liquid supply system.

[0020] Optionally, a sewage discharge joint is provided at one end of the heat absorbing tube away from the flushing head, the sewage discharge joint is arranged opposite to the flushing head, and the shape of the flushing head is also adapted to the shape of the inner circle of the heat absorbing channel; The sewage discharge joint is connected with a sewage discharge pipe, and one end of the sewage discharge pipe away from the sewage discharge joint is connected with the sedimentation chamber.

[0021] By adopting the above technical solution, a sewage connection is set at the end of the heat absorption tube away from the flushing head, and the sewage connection is opposite to the flushing head to ensure that the sewage in the flushing process can be discharged smoothly. At the same time, the sewage connection is connected to the sewage pipe, and the sewage pipe is finally connected to the sedimentation chamber to achieve effective collection and treatment of sewage and avoid secondary pollution. In addition, the design of the shape of the flushing head matching the shape of the inner circle of the heat absorption channel ensures the comprehensiveness and efficiency of the cleaning operation and improves the stable operation ability of the system.

[0022] Optionally, a rotating cylinder is coaxially fixed to one end of the heat absorption cylinder, and the driving assembly includes a driving source, a driven gear and a driving gear that mesh with each other, the driven gear is coaxially sleeved outside the rotating cylinder, and the driving source is used to drive the driving gear to rotate.

[0023] By adopting the above technical solution, the heat absorption tube can be rotated, so that different heat absorption channels in the heat absorption tube can be rotated to correspond to the flushing head and the sewage discharge joint, thereby realizing the cleaning of different heat exchange channels in the heat absorption tube; and when a certain heat exchange channel is cleaned under the action of the backwashing component, the remaining heat exchange channels can still participate in the normal heat exchange of the flue gas.

[0024] Optionally, the water recycler is connected to a recycling tank, and one end of the liquid supply pipe located outside the heat exchange tank body is connected to the recycling tank; The liquid supply pipe is also provided with a liquid supply pump, and the liquid supply pump is used to drive the circulating water in the recycling tank to flow into the liquid supply pipe.

[0025] By adopting the above technical solution, a liquid supply pump is added to drive the circulating water in the reuse tank to flow to the liquid supply pipe, ensuring that the backwash component obtains a stable supply of working medium, thereby improving the cleaning efficiency and reliability of the heat absorption tube; the introduction of the reuse tank enables the treated condensed water to be properly stored and reused, which not only reduces the demand for external water sources, but also reduces the amount of wastewater discharged, thereby improving the environmental performance of the entire system.

[0026] In summary, the present application includes at least one of the following beneficial effects: 1. The total heat exchanger in this application performs multiple heat and mass transfer exchanges with the flue gas through the spray assembly, which can absorb the sensible heat of the flue gas and the latent heat of water vapor at the same time, greatly improving the overall recovery rate of the flue gas waste heat; 2. The inner wall of the heat exchange tank in this application is coated with glass flakes, which effectively solves the dew point corrosion problem caused by flue gas condensation, prolongs the service life of the equipment and ensures stable operation of the system; 3. In this application, the heat exchange tank is provided with a sedimentation chamber to collect condensed water and recycle it after treatment, thereby achieving effective recovery of moisture in the flue gas, reducing water resource waste, and reducing environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall structure of a system for utilizing waste heat from flue gas in an alumina roasting furnace according to Example 1 of the present application; Figure 2 is a schematic cross-sectional structural diagram of the heat exchange tank body in Example 1 of the present application; Figure 3 This is a schematic diagram of the overall structure of a system for utilizing waste heat from flue gas in an alumina roasting furnace according to Example 2 of the present application; Figure 4 is a schematic cross-sectional structural diagram of a heat exchange tank in Example 2 of the present application; Figure 5 It is a schematic diagram of the structure of the heat absorbing tube in Example 2 of the present application; Figure 6 is a schematic cross-sectional structural diagram of the heat exchange tank body from another perspective in Example 2 of the present application; Explanation of reference numerals: 1. Total heat exchanger; 11. Heat exchange tank; 111. Sedimentation chamber; 112. Mounting ring groove; 12. Spray assembly; 121. Spray head; 122. Water spray plate; 1221. Water spray hole; 13. Smoke inlet channel; 131. Third opening and closing valve; 14. Smoke exhaust channel; 141. Second opening and closing valve; 15. Smoke exhaust branch pipe; 151. First opening and closing valve; 2. Plate heat exchanger; 21. Heat exchanger body; 22. Heat recovery pipe; 23. Heat recovery inlet pipe; 24. Heat utilization pipe; 25. Heat utilization inlet pipe; 3. Circulating water supply system; 31. Water outlet pipe ; 32. Return pipe; 33. Circulation pump; 4. Water replenishment assembly; 41. Water replenishment pipe; 42. Water replenishment pump; 5. Water recovery device; 51. Recovery liquid pipe; 6. Recovery pump; 7. Heat absorption cylinder; 71. Cylinder body; 711. Rotating cylinder; 72. Heat absorption channel; 73. Heat absorption fins; 74. Partition plate; 75. Drain pipe; 8. Drive assembly; 81. Driven gear; 82. Driving gear; 83. Drive source; 9. Backwash assembly; 91. Flushing head; 92. Cleaning nozzle; 93. Liquid supply pipe; 94. Drain connector; 95. Liquid supply pump; 96. Hose; 10. Reuse tank. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1-6 This application is described in further detail.

[0029] Embodiment 1: Embodiment 1 of the present application provides a system for utilizing waste heat from flue gas of an alumina roasting furnace.

[0030] Reference Figure 1 and Figure 2, a flue gas waste heat utilization system of an alumina roasting furnace, comprising a total heat exchanger 1, a plate heat exchanger 2 and a circulating water supply system 3; wherein the total heat exchanger 1 comprises a heat exchange tank body 11, a spray assembly 12 and a sedimentation chamber 111 arranged inside the heat exchange tank body 11. The bottom of the heat exchange tank body 11 is connected to a smoke inlet channel 13 to introduce the flue gas to be treated; the top of the heat exchange tank body 11 is connected to a smoke exhaust channel 14 to ensure smooth discharge of the flue gas after heat exchange. The smoke inlet channel 13 is connected to a smoke exhaust branch pipe 15, and one end of the smoke exhaust branch pipe 15 is connected to the smoke exhaust channel 14. A first opening and closing valve 151 is installed on the pipe section of the smoke exhaust branch pipe 15, a second opening and closing valve 141 is installed on the pipe section of the smoke exhaust channel 14, and a third opening and closing valve 131 is installed on the pipe section of the smoke inlet channel 13. In this embodiment, the first on-off valve 151 , the second on-off valve 141 , and the third on-off valve 131 are all electric blind plate valves.

[0031] Reference Figure 2 The inner wall of the heat exchange tank body 11 is also coated with a glass flake coating to prevent the acidic substances generated during the heat exchange process from penetrating into the surface of the metal substrate, thereby preventing the occurrence of electrochemical corrosion caused by long-term exposure to a corrosive environment. The spray assembly 12 specifically includes a spray head 121 located at the top of the heat exchange tank body 11 and a water spray plate 122 arranged below the spray head 121, and a plurality of water spray plates 122 are arranged at intervals below the spray head 121. In the present embodiment, each water spray plate 122 is made of a material with heat-resistant and wear-resistant properties, such as engineering plastics or alloy steel. In the present embodiment, the water spray plate 122 is specifically selected to be a semi-circular disc structure. A plurality of water spray holes 1221 are provided on each layer of the water spray plate 122, and the water spray holes 1221 on the water spray plate 122 are concentrated in the area of ​​the water spray plate 122 away from the arc-shaped side.

[0032] Reference Figure 2 Each layer of water spraying pans 122 is fixed to the heat exchange tank 11 by bolts or other means, and each layer of water spraying pans 122 maintains an appropriate spacing, so that water can flow through the small holes on each layer of water spraying pans 122 from top to bottom to form a continuous water flow curtain, thereby increasing the contact area and promoting a more efficient heat exchange process. The adjacent two layers of water spraying pans 122 are arranged in an up-and-down staggered manner, which further enhances the turbulence effect and improves the overall heat exchange performance.

[0033] Reference Figure 1 and Figure 2, the sedimentation chamber 111 is located below the spray assembly 12, and the sedimentation chamber 111 is connected to a recovery liquid pipe 51, one end of which is located outside the heat exchange tank 11 and connected to a water recovery device 5. The flue gas contains moisture, which is condensed after passing through the total heat exchanger 1. As time goes by, the amount of flue gas condensation gradually increases, but the heat power of the waste water recovered by the total heat exchanger 1 is rated. Therefore, there will be excess condensed water, and the condensed water enters the sedimentation chamber 111. The recovery pump 6 is connected to the pipe section of the recovery liquid pipe 51, and the recovery pump 6 can drive the circulating water in the sedimentation chamber 111 to move toward the water recovery device 5. After the condensed water enters the water recovery device 5, it is filtered and precipitated again. Because the water vapor in the flue gas condenses and reacts with sulfur trioxide in the flue gas, sulfuric acid is produced, which is acidic. Alkaline substances such as sodium carbonate are added to the water recovery device 5 to neutralize the acidity in the water. The pH value is detected online to reach the neutral water standard, so that the moisture in the flue gas is recovered and the waste of water resources is avoided.

[0034] Reference Figure 1 The plate heat exchanger 2 includes a heat exchanger body 21, and a heat recovery inlet pipe 23, a heat recovery exhaust pipe 22, a heat utilization inlet pipe 25 and a heat utilization exhaust pipe 24 connected to the heat exchanger body 21. Among them, the heat recovery inlet pipe 23 and the heat recovery exhaust pipe 22 are located on one side of the heat exchanger body 21, and the heat utilization inlet pipe 25 and the heat utilization exhaust pipe 24 are located on the other side of the heat exchanger body 21. Butterfly valves are installed on the pipe sections of the heat recovery inlet pipe 23, the heat recovery exhaust pipe 22, the heat utilization inlet pipe 25 and the heat utilization exhaust pipe 24. The plate heat exchanger 2 mainly receives the high-temperature circulating water transmitted from the total heat exchanger 1 and transfers the heat energy contained therein to other media.

[0035] Reference Figure 1 and Figure 2 , the circulating water supply system 3 is connected between the total heat exchanger 1 and the plate heat exchanger 2. The circulating water supply system 3 includes a water outlet pipe 31, a water return pipe 32 and a circulating pump 33. One end of the water return pipe 32 is arranged in the heat exchange tank body 11 along the top of the heat exchange tank body 11, and is connected to the sprinkler head 121, and the other end of the water return pipe 32 is connected to the heat recovery drain pipe 22. One end of the water outlet pipe 31 is connected to the bottom of the heat exchange tank body 11, and the other end is connected to the heat recovery inlet pipe 23; the circulating pump 33 is installed in the pipe section of the water outlet pipe 31 to maintain the necessary pressure to promote the circulation of water. In this embodiment, two circulating pumps 33 are connected in parallel in the pipe section of the water outlet pipe 31. In addition, a water replenishment component 4 is also provided, and the water replenishment component 4 includes a water replenishment pipe 41 and a water replenishment pump 42. One end of the water replenishment pipe 41 is connected to the water outlet pipe 31, so as to replenish the lost water when necessary to maintain the stable operation state of the system. The water supply pump 42 is connected to the pipe section of the water supply pipe 41. In this embodiment, two water supply pumps 42 are also connected in parallel in the pipe section of the water supply pipe 41. In actual use, only one circulation pump 33 and water supply pump 42 are used separately, and the redundant circulation pumps 33 and water supply pumps 42 are used as backup.

[0036] The implementation principle of the flue gas waste heat utilization system of an alumina roasting furnace in Example 1 of the present application is as follows: cooling water is pressurized by a circulating pump 33 and pumped into the top of the heat exchange tank body 11, and sprayed through the spray head 121 to form layered conical water droplets, which undergo the first heat and mass transfer exchange with the flue gas rising from the bottom of the heat exchange tank body 11. The circulating water then falls onto the step-by-step water spraying tray 122 provided on the equipment, and forms a columnar water flow through the water spraying holes 1221 on the water spraying tray 122 to undergo a secondary heat and mass transfer exchange with the high-temperature humid flue gas entering the equipment from the smoke inlet channel 13 at the bottom of the heat exchange tank body 11 to obtain high-temperature water, which then flows out of the heat exchange tank body 11 through the heat recovery drain pipe 22. The high-temperature water in the heat recovery drain pipe 22 is transported to the plate heat exchanger 2 via the circulating water supply system 3 for energy transfer, and is ultimately applied to fields such as preheating of desalted water in power plants to maximize the cascade utilization of energy.

[0037] Embodiment 2: Embodiment 2 of the present application provides a system for utilizing waste heat from flue gas of an alumina roasting furnace.

[0038] refer to Figure 3 and Figure 4 , the difference between Example 2 of the present application and Example 1 is that: On this basis, a heat absorbing tube 7 is added to further enhance the flue gas waste heat capture capability. The heat absorbing tube 7 is located below the spray assembly 12. Figure 4 and Figure 5 The heat absorbing tube 7 includes a cylinder 71, a sewage pipe 75 and a partition plate 74 are arranged in the cylinder 71, the sewage pipe 75 is coaxially arranged with the heat absorbing tube 7, the partition plate 74 is fixed between the outer wall of the sewage pipe 75 and the inner wall of the cylinder 71, and a plurality of partition plates 74 are arranged at intervals around the axis of the cylinder 71. The sewage pipe 75 and the plurality of partition plates 74 divide the interior of the cylinder 71 into a plurality of heat absorbing channels 72, and a plurality of heat absorbing fins 73 are fixed in each heat absorbing channel 72 to increase the specific surface area and facilitate faster and better heat absorption. The inner wall of the heat exchange tank 11 is formed with a mounting ring groove 112, and the heat absorbing tube 7 is clamped in the mounting ring groove 112 to realize the rotation connection of the heat absorbing tube 7 in the heat exchange tank 11.

[0039] Reference Figure 4 and Figure 6In order to facilitate daily cleaning and maintenance operations, a backwashing assembly 9 is specially equipped. The backwashing assembly 9 includes a flushing head 91, a cleaning nozzle 92 and a sewage connection 94. The flushing head 91 is located below the heat absorbing tube 7 and is fixed on the inner wall of the heat exchange tank body 11. The shape of the flushing head 91 is adapted to the cross section of the heat absorbing channel 72. The flushing head 91 is connected with a plurality of cleaning nozzles 92, and the cleaning nozzles 92 are arranged toward the heat absorbing channel 72. The shape of the sewage connection 94 is also adapted to the cross section of the heat absorbing channel 72. The sewage connection 94 is located at one end of the heat absorbing tube 7 away from the flushing head 91, and the sewage connection 94 is arranged opposite to the flushing head 91. The sewage connection 94 is specifically a trough structure, and the sewage connection 94 is also fixed on the inner wall of the heat exchange tank body 11; the sewage connection 94 is connected with a hose 96, and the hose 96 is inserted into the sewage pipe 75 at one end and communicates with the sewage pipe 75. The sedimentation chamber 111 is connected to a sewage pipe 75, and one end of the sewage pipe 75 is inserted into the sewage pipe 75 and communicated with the sewage pipe 75. The backwashing component 9 regularly clears and dredges the sediment inside the heat absorption channel 72 to restore the original function.

[0040] Reference Figure 6 , after the bottom of the sewage pipe 75 passes through the heat absorption cylinder 7, a rotating cylinder 711 is coaxially fixed thereto, and a driving assembly 8 is also provided in the heat exchange tank body 11. The driving assembly 8 includes a driving source 83, a driven gear 81 and a driving gear 82 that mesh with each other; the driven gear 81 is coaxially sleeved outside the rotating cylinder 711 and fixedly connected to the rotating cylinder 711. In this embodiment, the driving source 83 is specifically a driving motor, which is fixed in the heat exchange tank body 11, and the output shaft of the driving motor is coaxially fixed to the driving gear 82. By starting the driving motor, the rotating cylinder 711 can be driven to rotate, so that the different heat absorption channels 72 in the cylinder body 71 can all move to be opposite to the flushing head 91 and the sewage discharge joint 94.

[0041] Reference Figure 3 In this embodiment, a recycling tank 10 is further provided, and the recycling tank 10 is connected to the water recovery device 5 through a pipeline. The water treated in the water recovery device 5 that meets the standards can be discharged into the recycling tank 10 for collection. The recycling tank 10 is connected with a liquid supply pipe 93, one end of which penetrates into the heat exchange tank body 11 and is connected to the flushing head 91; the pipe section of the liquid supply pipe 93 is connected with a liquid supply pump 95 to drive the water in the recycling tank 10 to flow into the flushing head 91 to supply liquid to the backwashing component 9.

[0042] The implementation principle of the alumina roasting furnace flue gas waste heat utilization system in Example 2 of the present application is as follows: the newly added heat absorption tube 7 device greatly expands the effective interface area that directly interacts with the flue gas by means of the built-in densely arranged array of heat absorption fins 73, and the use of the backwash component 9 ensures the long-term stable and reliable operation performance of the system.

[0043] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A system for utilizing waste heat from flue gas of an alumina roasting furnace, characterized in that: include: A total heat exchanger (1) comprises a heat exchange tank body (11), a spray assembly (12) arranged in the heat exchange tank body (11), and a sedimentation chamber (111), wherein the inner wall of the heat exchange tank body (11) is coated with glass flakes; the spray assembly (12) comprises a spray head (121) and a water spray tray (122) arranged below the spray head (121), wherein the water spray tray (122) is provided with a plurality of water spray holes (1221), and the water spray tray (122) is provided with a plurality of holes at intervals in the vertical direction; the bottom of the heat exchange tank body (11) is connected to a smoke inlet channel (13), and the top of the heat exchange tank body (11) is connected to a smoke exhaust channel (14); The plate heat exchanger (2) comprises a heat exchanger body (21), a heat recovery drain pipe (22) and a heat recovery inlet pipe (23) connected to one side of the heat exchanger body (21), and a heat utilization drain pipe (24) and a heat utilization inlet pipe (25) connected to the other side of the heat exchanger body (21); A circulating water supply system (3) is connected between the plate heat exchanger (2) and the heat exchange tank body (11), and is used to drive the circulating water in the heat exchange tank body (11) to flow through the plate heat exchanger (2) and then to flow toward the spray head (121).

2. The alumina roasting furnace flue gas waste heat utilization system according to claim 1, characterized in that: The circulating water supply system (3) comprises a water outlet pipe (31), a water return pipe (32) and a circulating pump (33); one end of the water outlet pipe (31) is connected to the bottom of the heat exchange tank (11), and the other end is connected to the heat recovery inlet pipe (23); one end of the water return pipe (32) is connected to the heat recovery discharge pipe (22), and the other end is connected to the sprinkler head (121); the circulating pump (33) is connected to the pipe section of the water outlet pipe (31) and is used to drive the circulating water in the water outlet pipe (31) to move toward the heat recovery inlet pipe (23).

3. The alumina roasting furnace flue gas waste heat utilization system according to claim 2, characterized in that: It also comprises a water replenishment assembly (4), the water replenishment assembly (4) comprising a water replenishment pipe (41) and a water replenishment pump (42), one end of the water replenishment pipe (41) being in communication with the water outlet pipe (31); the water replenishment pump (42) being in communication with the pipe section of the water replenishment pipe (41) and being used for driving the circulating water in the water replenishment pipe (41) to move towards the water outlet pipe (31).

4. The alumina roasting furnace flue gas waste heat utilization system according to claim 1, characterized in that: It also comprises a water recovery device (5), the water recovery device (5) being connected to a recovery liquid pipe (51), the recovery liquid pipe (51) being connected to the sedimentation chamber (111); a recovery pump (6) is arranged on the recovery liquid pipe (51), the recovery pump (6) being used to drive the circulating water in the sedimentation chamber (111) to flow into the water recovery device (5).

5. The alumina roasting furnace flue gas waste heat utilization system according to claim 1, characterized in that: The smoke inlet channel (13) is connected to a smoke exhaust branch pipe (15), the smoke exhaust branch pipe (15) is connected to the smoke exhaust channel (14), and a first opening and closing valve (151) is provided on the smoke exhaust branch pipe (15).

6. The alumina roasting furnace flue gas waste heat utilization system according to claim 4, characterized in that: A heat absorbing tube (7) is also provided in the heat exchange tank body (11), and the heat absorbing tube (7) is located below the spray assembly (12); The heat absorbing cylinder (7) comprises a cylinder body (71) and a heat absorbing channel (72) arranged in the cylinder body (71), wherein a plurality of the heat absorbing channels (72) are arranged at intervals around the axis of the cylinder body (71), and each of the heat absorbing channels (72) is provided with a plurality of heat absorbing fins (73).

7. The alumina roasting furnace flue gas waste heat utilization system according to claim 6, characterized in that: The heat absorbing cylinder (7) is rotatably disposed in the heat exchange tank body (11), and a driving component (8) for driving the cylinder body (71) to rotate is disposed in the heat exchange tank body (11); A backwashing assembly (9) is also provided in the heat exchange tank body (11), the backwashing assembly (9) comprising a flushing head (91) and a plurality of cleaning nozzles (92) connected to one end of the flushing head (91), the flushing head (91) being located below one of the heat absorbing channels (72), and the shape of the flushing head (91) being adapted to the shape of the inner circle of the heat absorbing channel (72); The flushing head (91) is connected to a liquid supply pipe (93), and one end of the liquid supply pipe (93) is located outside the heat exchange tank body (11).

8. The alumina roasting furnace flue gas waste heat utilization system according to claim 7, characterized in that: A sewage discharge joint (94) is provided at one end of the heat absorbing tube (7) away from the flushing head (91); the sewage discharge joint (94) is arranged opposite to the flushing head (91); and the shape of the flushing head (91) is also adapted to the shape of the inner circle of the heat absorbing channel (72); The sewage discharge joint (94) is connected to a sewage discharge pipe (75), and one end of the sewage discharge pipe (75) away from the sewage discharge joint (94) is connected to the sedimentation chamber (111).

9. The alumina roasting furnace flue gas waste heat utilization system according to claim 7, characterized in that: A rotating cylinder (711) is coaxially fixed to one end of the heat absorbing cylinder (7), and the driving assembly (8) comprises a driving source (83), a driven gear (81) and a driving gear (82) that mesh with each other, the driven gear (81) being coaxially sleeved outside the rotating cylinder (711), and the driving source (83) being used to drive the driving gear (82) to rotate.

10. The alumina roasting furnace flue gas waste heat utilization system according to claim 7, characterized in that: The water recovery device (5) is connected to a recycling tank (10), and one end of the liquid supply pipe (93) located outside the heat exchange tank body (11) is connected to the recycling tank (10); The liquid supply pipe (93) is also provided with a liquid supply pump (95), and the liquid supply pump (95) is used to drive the circulating water in the recycling tank (10) to flow into the liquid supply pipe (93).

Images